Afzal, MU & Esselle, KP 2017, 'Steering the Beam of Medium-to-High Gain Antennas Using Near-Field Phase Transformation', IEEE Transactions on Antennas and Propagation, vol. 65, no. 4, pp. 1680-1690.
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A method to steer the beam of aperture-type antennas is presented in this paper. Beam steering is achieved by transforming phase of the antenna near field using a pair of totally passive metasurfaces, which are located just above and parallel to the antenna. They are rotated independently or synchronously around the antenna axis. A prototype, with a peak gain of 19.4 dBi, demonstrated experimentally that the beam of a resonant cavity antenna can be steered to any direction within a large conical region (with an apex angle of 102°), with less than 3-dB gain variation, by simply turning the two metasurfaces without moving the antenna at all. Measured gain variation within a 92° cone is only 1.9 dBi. Contrary to conventional mechanical steering methods, such as moving reflector antennas with multiaxis rotary joints, the 3-D volume occupied by this antenna system does not change during beam steering. This advantage, together with its low profile, makes it a strong contender for space-limited applications where beam steering with active devices is not desirable due to cost, nonlinear distortion, limited power handling, sensitivity to temperature variations, radio frequency losses, or associated heating. This beam steering method using near-field phase transformation can also be applied to other aperture-type antennas and arrays with medium-to-high gains.
Aguilera, RP, Acuna, P, Yu, Y, Konstantinou, G, Townsend, CD, Wu, B & Agelidis, VG 2017, 'Predictive Control of Cascaded H-Bridge Converters Under Unbalanced Power Generation', IEEE Transactions on Industrial Electronics, vol. 64, no. 1, pp. 4-13.
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© 1982-2012 IEEE.This work presents a predictive control strategy for grid-connected Cascaded H-Bridge (CHB) converters under unbalanced power generation among each converter phase. The proposed controller belongs to the Finite-Control-Set Model Predictive Control (FCS-MPC) family and is designed to extract unbalanced power from each CHB converter phase while providing balanced power to the grid. The key novelty of this strategy lies in the way the unbalanced power generation among the phases is explicitly considered into the optimal control problem. Power balance is achieved by enforcing the CHB converter to work with a suitable zero-sequence voltage component. The proposed predictive controller is directly formulated in the original abc-framework to account for the commonmode voltage. Simulation and experimental results are provided to verify the effectiveness of the proposed FCS-MPC strategy.
Aguilera, RP, Urrutia, G, Delgado, RA, Dolz, D & Aguero, JC 2017, 'Quadratic Model Predictive Control Including Input Cardinality Constraints', IEEE Transactions on Automatic Control, vol. 62, no. 6, pp. 3068-3075.
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© 2017 IEEE. This note addresses the problem of feedback control with a constrained number of active inputs. This problem is known as sparse control. Specifically, we describe a novel quadratic model predictive control strategy that guarantees sparsity by bounding directly the l0-norm of the control input vector at each control horizon instant. Besides this sparsity constraint, bounded constraints are also imposed on both control input and system state. Under this scenario, we provide sufficient conditions for guaranteeing practical stability of the closed-loop. We transform the combinatorial optimization problem into an equivalent optimization problem that does not consider relaxation in the cardinality constraints. The equivalent optimization problem can be solved utilizing standard nonlinear programming toolboxes that provides the input control sequence corresponding to the global optimum.
Ahmed, M, Wang, B, Gupta, B, Boeckl, JJ, Motta, N & Iacopi, F 2017, 'On-Silicon Supercapacitors with Enhanced Storage Performance', Journal of The Electrochemical Society, vol. 164, no. 4, pp. A638-A644.
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© 2017 The Electrochemical Society. All rights reserved. The expanding development of portable electronic devices and ubiquitous sensing systems has created a strong demand for efficient miniaturized energy storage units, with planar geometries and capable of being integrated on a silicon platform. Generally, the performance of thin-film storage devices, including using graphene, is dramatically limited by their low surface area for ionexchange. We had recently shown that a higher number of graphene layers does not translate into higher storage performance. Here we show a way to overcome this limitation and achieve a maximum accessible area for ion exchange. A repeated graphitization strategy using a nickel catalyst on epitaxial silicon carbide films on silicon yields few-layers graphenic nanocarbon electrodes with prominent edge defects, facilitating the intercalation between multiple graphenic sheets while maintaining overall a high electrode conductivity.
Alturki, R & Gay, V 2017, 'Usability Testing of Fitness Mobile Application : Case Study Aded Surat App', International Journal of Computer Science and Information Technology, vol. 9, no. 5, pp. 105-125.
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Amin, U, Hossain, MJ, Lu, J & Fernandez, E 2017, 'Performance analysis of an experimental smart building: Expectations and outcomes', Energy, vol. 135, pp. 740-753.
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Amiri, M, Tofigh, F, Ghafoorzadeh Yazdi, A & Abolhasan, M 2017, 'Exponential Antipodal Vivaldi Antenna With Exponential Dielectric Lens', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 1-1.
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Amjadipour, M, MacLeod, J, Lipton-Duffin, J, Iacopi, F & Motta, N 2017, 'Epitaxial graphene growth on FIB patterned 3C-SiC nanostructures on Si (111): reducing milling damage', Nanotechnology, vol. 28, no. 34, pp. 345602-345602.
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Epitaxial growth of graphene on SiC is a scalable procedure that does not require any further transfer step, making this an ideal platform for graphene nanostructure fabrication. Focused ion beam (FIB) is a very promising tool for exploring the reduction of the lateral dimension of graphene on SiC to the nanometre scale. However, exposure of graphene to the Ga+ beam causes significant surface damage through amorphisation and contamination, preventing epitaxial graphene growth. In this paper we demonstrate that combining a protective silicon layer with FIB patterning implemented prior to graphene growth can significantly reduce the damage associated with FIB milling. Using this approach, we successfully achieved graphene growth over 3C-SiC/Si FIB patterned nanostructures.
Antunes, N, Pipiras, V, Abry, P & Veitch, D 2017, 'Small and large scale behavior of moments of Poisson cluster processes', ESAIM: Probability and Statistics, vol. 21, pp. 369-393.
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Poisson cluster processes are special point processes that find use in modeling Internet traffic, neural spike trains, computer failure times and other real-life phenomena. The focus of this work is on the various moments and cumulants of Poisson cluster processes, and specifically on their behavior at small and large scales. Under suitable assumptions motivated by the multiscale behavior of Internet traffic, it is shown that all these various quantities satisfy scale free (scaling) relations at both small and large scales. Only some of these relations turn out to carry information about salient model parameters of interest, and consequently can be used in the inference of the scaling behavior of Poisson cluster processes. At large scales, the derived results complement those available in the literature on the distributional convergence of normalized Poisson cluster processes, and also bring forward a more practical interpretation of the so-called slow and fast growth regimes. Finally, the results are applied to a real data trace from Internet traffic.
Argha, A, Li, L & Su, SW 2017, 'Design ofH2(H∞)-based optimal structured and sparse static output feedback gains', Journal of the Franklin Institute, vol. 354, no. 10, pp. 4156-4178.
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© 2017 The Franklin Institute This paper is devoted to the problem of designing an H2 (H∞)-based optimal sparse static output feedback (SOF) controller for continuous linear time invariant systems. Incorporating an extra term for penalising the number of non-zero entries of the static output (state) feedback gain into the optimisation objective function, we propose an explicit scheme and an iterative process in order to identify the desired sparse structure of the feedback gain. In doing so, the so-called reweighted ℓ1-norm, which is known as a convex relaxation of the ℓ0-norm, is exploited to make a convex problem through an iterative process rather than the original NP-hard problem. This paper will also show that this problem reformulation allows us to incorporate additional constraints, such as regional pole placement constraints which provide more control over the satisfactory transient behavior and closed-loop pole location, into the designing problem. Then using the obtained structural constraints, we solve the structural H2 (H∞) SOF problem. Illustrative examples are presented to show the effectiveness of the proposed approaches.
Argha, A, Li, L & W. Su, S 2017, 'Sliding mode stabilisation of networked systems with consecutive data packet dropouts using only accessible information', International Journal of Systems Science, vol. 48, no. 6, pp. 1291-1300.
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© 2016 Informa UK Limited, trading as Taylor & Francis Group. This paper develops a novel stabilising sliding mode for systems involving uncertainties as well as measurement data packet dropouts. In contrast to the existing literature that designs the switching function by using unavailable system states, a novel linear sliding function is constructed by employing only the available communicated system states for the systems involving measurement packet losses. This also equips us with the possibility to build a novel switching component for discrete-time sliding mode control (DSMC) by using only available system states. Finally, using a numerical example, we evaluate the performance of the designed DSMC for networked systems.
Argha, A, Su, SW & Celler, BG 2017, 'Heart rate regulation during cycle-ergometer exercise via event-driven biofeedback', Medical & Biological Engineering & Computing, vol. 55, no. 3, pp. 483-492.
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© 2016, International Federation for Medical and Biological Engineering. This paper is devoted to the problem of regulating the heart rate response along a predetermined reference profile, for cycle-ergometer exercises designed for training or cardio-respiratory rehabilitation. The controller designed in this study is a non-conventional, non-model-based, proportional, integral and derivative (PID) controller. The PID controller commands can be transmitted as biofeedback auditory commands, which can be heard and interpreted by the exercising subject to increase or reduce exercise intensity. However, in such a case, for the purposes of effectively communicating to the exercising subject a change in the required exercise intensity, the timing of this feedback signal relative to the position of the pedals becomes critical. A feedback signal delivered when the pedals are not in a suitable position to efficiently exert force may be ineffective and this may, in turn, lead to the cognitive disengagement of the user from the feedback controller. This note examines a novel form of control system which has been expressly designed for this project. The system is called an “actuator-based event-driven control system”. The proposed control system was experimentally verified using 24 healthy male subjects who were randomly divided into two separate groups, along with cross-validation scheme. A statistical analysis was employed to test the generalisation of the PID tunes, derived based on the average transfer functions of the two groups, and it revealed that there were no significant differences between the mean values of root mean square of the tracking error of two groups (3.9 vs. 3.7 bpm, p= 0.65). Furthermore, the results of a second statistical hypothesis test showed that the proposed PID controller with novel synchronised biofeedback mechanism has better performance compared to a conventional PID controller with a fixed-rate biofeedback mechanism (Group 1: 3.9 vs...
Asheralieva, A & Miyanaga, Y 2017, 'Optimal Contract Design for Joint User Association and Intercell Interference Mitigation in Heterogeneous LTE-A Networks With Asymmetric Information', IEEE Transactions on Vehicular Technology, vol. 66, no. 6, pp. 5284-5300.
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Awwad, S & Piccardi, M 2017, 'Prototype-based budget maintenance for tracking in depth videos', Multimedia Tools and Applications, vol. 76, no. 20, pp. 21117-21132.
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© 2016 Springer Science+Business Media New YorkThe use of conventional video tracking based on color or gray-level videos often raises concerns about the privacy of the tracked targets. To alleviate this issue, this paper presents a novel tracker that operates solely from depth data. The proposed tracker is designed as an extension of the popular Struck algorithm which leverages the effective framework of structural SVM. The main contributions of our paper are: i) a dedicated depth feature based on local depth patterns, ii) a heuristic for handling view occlusions in depth frames, and iii) a technique for keeping the number of the support vectors within a given “budget” so as to limit computational costs. Experimental results over the challenging Princeton Tracking Benchmark (PTB) dataset report a remarkable accuracy compared to the original Struck tracker and other state-of-the-art trackers using depth and RGB data.
Baba, AA, Hashmi, RM & Esselle, KP 2017, 'Achieving a Large Gain-Bandwidth Product From a Compact Antenna', IEEE Transactions on Antennas and Propagation, vol. 65, no. 7, pp. 3437-3446.
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Belotti, Y, Huang, T, McKenna, S, Nabi, G & McGloin, D 2017, 'High-throughput, imaging based mechanical phenotyping of prostate cancer cells', Optics InfoBase Conference Papers, vol. Part F81-EQEC 2017.
Bluff, A & Johnston, A 2017, 'Creature:Interactions: A Social Mixed-Reality Playspace', Leonardo, vol. 50, no. 4, pp. 360-367.
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This paper discusses Creature:Interactions (2015), a large-scale mixed-reality artwork created by the authors that incorporates immersive 360° stereoscopic visuals, interactive technology, and live actor facilitation. The work uses physical simulations to promote an expressive full-bodied interaction as children explore the landscapes and creatures of Ethel C. Pedley’s ecologically focused children’s novel, Dot and the Kangaroo. The immersive visuals provide a social playspace for up to 90 people and have produced “phantom” sensations of temperature and touch in certain participants.
Bobba, SS & Agrawal, A 2017, 'Ultra-broad Mid-IR Supercontinuum Generation in Single, Bi and Tri Layer Graphene Nano-Plasmonic waveguides pumping at Low Input Peak Powers', Scientific Reports, vol. 7, no. 1.
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AbstractThis article presents four different plasmonic structures using Graphene which yielded an efficient plasmonic mode with low loss for Supercontinuum(SC) generation. At an operating wavelength of 1550 nm in these structures, we generated a multi-octave broadband SC spectrum ranging from 1.5 um–25 um at a low input peak power of 1 W. Due to pumping in the anomalous dispersion region with two Zero Dispersion Wavelengths (ZDWs) and the process of cross phase modulation with soliton fission, red-shifted dispersive waves were generated which led to large broadening from 1.5 um–25 um. Two other Supercontinua ranging from 1–10 um and 0.85–2.2 um also at low input peak powers of 2 W and 0.1 W respectively were generated. These three supercontinua are useful for applications in the fields of biomedical sensors, spectroscopy, fluorescence lifetime imaging and in the design of many other new optical devices. Furthermore, we have also discussed our results on behaviour of Graphene as a metal, even without the negative real value of dielectric constant.
Bożejko, W, Chaczko, Z, Uchroński, M & Wodecki, M 2017, 'Parallel patterns determination in solving cyclic flow shop problem with setups', Archives of Control Sciences, vol. 27, no. 2, pp. 183-195.
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AbstractThe subject of this work is the new idea of blocks for the cyclic flow shop problem with setup times, using multiple patterns with different sizes determined for each machine constituting optimal schedule of cities for the traveling salesman problem (TSP). We propose to take advantage of the Intel Xeon Phi parallel computing environment during so-called ’blocks’ determination basing on patterns, in effect significantly improving the quality of obtained results.
Cai, Y, Zhang, Y, Ding, C & Qian, Z 2017, 'A Wideband Multilayer Substrate Integrated Waveguide Cavity-Backed Slot Antenna Array', IEEE Transactions on Antennas and Propagation, vol. 65, no. 7, pp. 3465-3473.
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© 2017 IEEE. In this paper, a wideband 2 × 2 multilayer substrate integrated waveguide (SIW)-based cavity-backed slot array is proposed. The array element is constructed by stacking five layers of SIW cavity-backed slots and has a wide impedance bandwidth from 18 to 30 GHz. Two different feed networks based on probe coupling and slot coupling are introduced to maintain the wideband characteristic of the proposed element when employed in an array. Two 2 × 2 arrays fed by the proposed feed networks are designed, fabricated, and tested. The measured results show that both the arrays employing probe coupling and slot coupling feed networks have a wide impedance bandwidth over 30%. Within the obtained operation bands, good radiation performance is achieved. Moreover, advantages and disadvantages of the proposed two feed networks are discussed.
Chai, R, Ling, SH, San, PP, Naik, GR, Nguyen, TN, Tran, Y, Craig, A & Nguyen, HT 2017, 'Improving EEG-Based Driver Fatigue Classification Using Sparse-Deep Belief Networks', Frontiers in Neuroscience, vol. 11, no. 103, pp. 1-14.
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This paper presents an improvement of classification performance for electroencephalography (EEG)-based driver fatigue classification between fatigue and alert states with the data collected from 43 participants. The system employs autoregressive (AR) modeling as the features extraction algorithm, and sparse-deep belief networks (sparse-DBN) as the classification algorithm. Compared to other classifiers, sparse-DBN is a semi supervised learning method which combines unsupervised learning for modeling features in the pre-training layer and supervised learning for classification in the following layer. The sparsity in sparse-DBN is achieved with a regularization term that penalizes a deviation of the expected activation of hidden units from a fixed low-level prevents the network from overfitting and is able to learn low-level structures as well as high-level structures. For comparison, the artificial neural networks (ANN), Bayesian neural networks (BNN) and original deep belief networks (DBN) classifiers are used. The classification results show that using AR feature extractor and DBN classifiers, the classification performance achieves an improved classification performance with a of sensitivity of 90.8%, a specificity of 90.4%, an accuracy of 90.6% and an area under the receiver operating curve (AUROC) of 0.94 compared to ANN (sensitivity at 80.8%, specificity at 77.8%, accuracy at 79.3% with AUC-ROC of 0.83) and BNN classifiers (sensitivity at 84.3%, specificity at 83%, accuracy at 83.6% with AUROC of 0.87). Using the sparse-DBN classifier, the classification performance improved further with sensitivity of 93.9%, a specificity of 92.3% and an accuracy of 93.1% with AUROC of 0.96. Overall, the sparse-DBN classifier improved accuracy by 13.8%, 9.5% and 2.5% over ANN, BNN and DBN classifiers respectively.
Chai, R, Naik, GR, Ling, SH & Nguyen, HT 2017, 'Hybrid brain–computer interface for biomedical cyber-physical system application using wireless embedded EEG systems', BioMedical Engineering OnLine, vol. 16, no. 1, pp. 1-23.
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© 2017 The Author(s). Background: One of the key challenges of the biomedical cyber-physical system is to combine cognitive neuroscience with the integration of physical systems to assist people with disabilities. Electroencephalography (EEG) has been explored as a non-invasive method of providing assistive technology by using brain electrical signals. Methods: This paper presents a unique prototype of a hybrid brain computer interface (BCI) which senses a combination classification of mental task, steady state visual evoked potential (SSVEP) and eyes closed detection using only two EEG channels. In addition, a microcontroller based head-mounted battery-operated wireless EEG sensor combined with a separate embedded system is used to enhance portability, convenience and cost effectiveness. This experiment has been conducted with five healthy participants and five patients with tetraplegia. Results: Generally, the results show comparable classification accuracies between healthy subjects and tetraplegia patients. For the offline artificial neural network classification for the target group of patients with tetraplegia, the hybrid BCI system combines three mental tasks, three SSVEP frequencies and eyes closed, with average classification accuracy at 74% and average information transfer rate (ITR) of the system of 27 bits/min. For the real-time testing of the intentional signal on patients with tetraplegia, the average success rate of detection is 70% and the speed of detection varies from 2 to 4 s.
Chai, R, Naik, GR, Nguyen, TN, Ling, SH, Tran, Y, Craig, A & Nguyen, HT 2017, 'Driver Fatigue Classification With Independent Component by Entropy Rate Bound Minimization Analysis in an EEG-Based System', IEEE Journal of Biomedical and Health Informatics, vol. 21, no. 3, pp. 715-724.
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This paper presents a two-class electroencephalography (EEG)-based classification for classifying of driver fatigue (fatigue state vs. alert state) from 43 healthy participants. The system uses independent component by entropy rate bound minimization analysis (ERBM-ICA) for the source separation, autoregressive (AR) modeling for the features extraction and Bayesian neural network for the classification algorithm. The classification results demonstrate a sensitivity of 89.7%, a specificity of 86.8% and an accuracy of 88.2%. The combination of ERBM-ICA (source separator), AR (feature extractor) and Bayesian neural network (classifier) provides the best outcome with a p-value < 0.05 with the highest value of area under the receiver operating curve (AUC-ROC=0.93) against other methods such as power spectral density (PSD) as feature extractor (AUC-ROC=0.81). The results of this study suggest the method could be utilized effectively for a countermeasure device for driver fatigue identification and other adverse event applications.
Chen, G, Chen, L, Deng, Y, He, X, Wang, Y & Zhang, J 2017, 'Single coupled‐inductor dual output soft‐switching DC–DC converters with improvedcross‐regulation and reduced components', IET Power Electronics, vol. 10, no. 13, pp. 1665-1678.
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© The Institution of Engineering and Technology. Single inductor dual-output (SIDO) DC-DC converters are attractive in diverse applications such as renewable energy systems and electric vehicles, due to its favourable advantages of reduced magnetic core and high-power density. However, in conventional SIDO converters, severe cross-regulation problem is caused by the multiplex of inductor current, resulting in deteriorated dynamic performance. To alleviate the cross-regulation problem, a new family of dual-output DC-DC converters is proposed in this paper, which employs a coupled inductor to substitute the inductor in SIDO converters. The proposed converters can achieve improved dynamic performance while keeping the advantage of reduced magnetic core. Moreover, the number of semiconductor devices is also reduced in comparison with conventional SIDO converters, and soft-switching operation of switches is also achieved. Therefore, lower cost and higher power density are obtained. Topology derivation of proposed converters from conventional SIDO converters is firstly demonstrated in detail. After that, the operation principle, steady-state characteristics and small-signal model are provided. Finally, design example and experiment results are given to validate the merits of the proposed topology.
Chen, S-L, Qin, P-Y, Ding, C & Guo, YJ 2017, 'Cavity-Backed Proximity-Coupled Reconfigurable Microstrip Antenna With Agile Polarizations and Steerable Beams', IEEE Transactions on Antennas and Propagation, vol. 65, no. 10, pp. 5553-5558.
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© 1963-2012 IEEE. A major challenge for a combined reconfigurable antenna is to realize both polarization switching and beam steering independently in a compact antenna structure. A cavity-backed proximity-coupled reconfigurable microstrip antenna proposed in this communication provides an efficient solution. Beam lead p-i-n diodes DSM8100-000 are employed as switching elements to achieve reconfiguration. Three different linear polarizations (0°, 45°, and 90°) are realized by switching the diodes on a proximity-coupled feed network. For each polarization state, the main beam can be steered to three directions by using a reconfigurable parasitic-element network. The parasitic-element network is printed on the same plane of the radiating patch, thereby making the antenna compact. This antenna has nine different working modes, and for all the working modes, the reflection coefficients are below -10 dB with the measured realized gains ranging from 7.2 to 8.1 dBi.
Chen, S-L, Qin, P-Y, Guo, YJ, Liu, Y & You, P 2017, 'Generalized 2-D Numerical Pattern Synthesis Algorithm for Low Cross Polarization and Low Sidelobe Synthesis', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 2578-2581.
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© 2017 IEEE. Numerical pattern synthesis (NPS) algorithm based on adaptive array theory is an effective spatial power pattern synthesis method for antenna arrays. In this letter, instead of using the artificial interferences weighted on the total power pattern in the conventional NPS algorithm, a generalized two-dimensional (2-D) NPS algorithm is proposed in which two weighting functions are assigned to control the copolarization and cross-polarization patterns, respectively. The weighting functions are iteratively updated until both the sidelobe and cross-polarization levels reach their prescribed ones. Two numerical examples for synthesizing the patterns of a linearly polarized planar array and a circularly polarized cylindrical array are provided to validate effectiveness and advantages of the proposed generalized 2-D NPS algorithm.
Chen, S-L, Wei, F, Qin, P-Y, Guo, YJ & Chen, X 2017, 'A Multi-linear Polarization Reconfigurable Unidirectional Patch Antenna', IEEE Transactions on Antennas and Propagation, vol. 65, no. 8, pp. 4299-4304.
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© 1963-2012 IEEE. A novel multi-linear polarization (multi-LP) reconfigurable unidirectional circular patch antenna is proposed, which can switch among four LPs at every 45° rotation. The patch antenna is fed in the center and shorting posts are used to excite TM11 mode with LP. By controlling the connections between the four shorting posts and the ground plane using p-i-n diodes, four reconfigurable polarization states at φ =0°, φ =45 , φ =90 , or φ =135 can be realized. The size of this antenna is about 0.57λ × 0.57λ × 0.07λ at 2.45 GHz. It can be easily fabricated and has a simple biasing network. The measured overlapping impedance bandwidth for different polarizations under the condition S 11≤ -10 dB is from 2.33 to 2.50 GHz, which agrees well with the simulated one. Moreover, the antenna maintains stable radiation patterns and the measured realized gains range from 5.3 to 5.9 dBi.
Chen, X, Qin, P-Y, Guo, YJ & Fu, G 2017, 'Low-Profile and Wide-Beamwidth Dual-Polarized Distributed Microstrip Antenna', IEEE Access, vol. 5, pp. 2272-2280.
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© 2013 IEEE. A low-profile and wide-beamwidth dual-polarized distributed microstrip antenna is presented in this paper. Four isolated micro patches are proposed as the radiation components and are excited by a compact differential-fed network. The micro patches in two diagonals determine the operating frequency bands of the two polarizations, respectively. By increasing the distances between the micro patches, the beamwidth in E plane can be broadened. Shorting poles between the patches and the ground plane are used to achieve good impedance matching. Compact dual-polarized differential-fed networks are also studied and compared with achieve the best antenna performance. To validate the proposed method, a wide-beamwith dual-polarized distributed microstrip antenna, whose dual polarizations operate at 2 and 2.2 GHz, respectively, is manufactured and measured. The external dimensions of the antenna is 70mm × 10 mm (0.49λ × 0.07λ ). The experimental results agree well with the simulated ones. The 3dB beamwidths in E planes reach 116° and 115°, and the gains are 5.15 and 5.5 dB for two polarizations, respectively. Meanwhile, the cross polarizations are less than -26.2 and -27.8 dB. In addition, the impedance bandwidths of 9.2% and 9.9% for VSWR leq 2 are achieved, and the port isolation is greater than 25.4 dB in the bands.
Chen, Y, Yue, X, Xu, RYD & Fujita, H 2017, 'Region scalable active contour model with global constraint', Knowledge-Based Systems, vol. 120, pp. 57-73.
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© 2016Existing Active Contour methods suffer from the deficiencies of initialization sensitivity, slow convergence, and being insufficient in the presence of image noise and inhomogeneity. To address these problems, this paper proposes a region scalable active contour model with global constraint (RSGC). The energy function is formulated by incorporating local and global constraints. The local constraint is a region scalable fitting term that draws upon local region information under controllable scales. The global constraint is constructed through estimating the global intensity distribution of image content. Specifically, the global intensity distribution is approximated with a Gaussian Mixture Model (GMM) and estimated by Expectation Maximization (EM) algorithm as a prior. The segmentation process is implemented through optimizing the improved energy function. Comparing with two other representative models, i.e. region-scalable fitting model (RSF) and active contour model without edges (CV), the proposed RSGC model achieves more efficient, stable and precise results on most testing images under the joint actions of local and global constraints.
Cheng, H, Zhang, J, Wu, Q, An, P & Liu, Z 2017, 'Stereoscopic visual saliency prediction based on stereo contrast and stereo focus', EURASIP Journal on Image and Video Processing, vol. 2017, no. 1.
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© 2017, The Author(s). In this paper, we exploit two characteristics of stereoscopic vision: the pop-out effect and the comfort zone. We propose a visual saliency prediction model for stereoscopic images based on stereo contrast and stereo focus models. The stereo contrast model measures stereo saliency based on the color/depth contrast and the pop-out effect. The stereo focus model describes the degree of focus based on monocular focus and the comfort zone. After obtaining the values of the stereo contrast and stereo focus models in parallel, an enhancement based on clustering is performed on both values. We then apply a multi-scale fusion to form the respective maps of the two models. Last, we use a Bayesian integration scheme to integrate the two maps (the stereo contrast and stereo focus maps) into the stereo saliency map. Experimental results on two eye-tracking databases show that our proposed method outperforms the state-of-the-art saliency models.
Cheng, T & Lu, DDC 2017, 'Three-port converters with a flexible power flow for integrating pv and energy storage into a DC bus', Journal of Power Electronics, vol. 17, no. 6, pp. 1433-1444.
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A family of non-isolated DC-DC three-port converters (TPCs) that allows for a more flexible power flow among a renewable energy source, an energy storage device and a current-reversible DC bus is introduced. Most of the reported non-isolated topologies in this area consider only a power consuming load. However, for applications such as hybrid-electric vehicle braking systems and DC microgrids, the load power generating capability should also be considered. The proposed three-port family consists of one unidirectional port and two bi-directional ports. Hence, they are well-suited for photovoltaic (PV)-battery-DC bus systems from the power flow viewpoint. Three-port converters are derived by combining different commonly known power converters in an integrated manner while considering the voltage polarity, voltage levels among the ports and the overall voltage conversion ratio. The derived converter topologies are able to allow for seven different modes of operation among the sources and load. A three-port converter which integrates a boost converter with a buck converter is used as a design example. Extensions of these topologies by combining the soft-switching technique with the proposed design example are also presented. Experiment results are given to verify the proposed three-port converter family and its analysis.
Cheng, Z, Zhu, J, Li, Y & Sievert, J 2017, 'The 14th International Workshop on 1&2 Dimensional Magnetic Measurement and Testing 23–25 September 2016, Tianjin, China', International Journal of Applied Electromagnetics and Mechanics, vol. 55, pp. 1-1.
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Cooper, CS, Franklin, DR, Ros, M, Safaei, F & Abolhasan, M 2017, 'A Comparative Survey of VANET Clustering Techniques.', IEEE Commun. Surv. Tutorials, vol. 19, no. 1, pp. 657-681.
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A vehicular ad hoc network (VANET) is a mobile ad hoc network (MANET) in which network nodes are vehicles – most commonly road vehicles. VANETs present a unique range of challenges and opportunities for routing protocols due to the semi-organised nature of vehicular movements subject to the constraints of road geometry and rules, and the obstacles which limit physical connectivity in urban environments. In particular, the problems of routing protocol reliability and scalability across large urban VANETs are currently the subject of intense research. Clustering can be used to improve routing scalability and reliability in VANETs, as it results in the distributed formation of hierarchical network structures by grouping vehicles together based on correlated spatial distribution and relative velocity. In addition to the benefits to routing, these groups can serve as the foundation for accident or congestion detection, inforomation dissemination and entertainment applications. This paper explores the design choices made in the development of clustering algorithms targeted at VANETs. It presents a taxonomy of the techniques applied to solve the problems of cluster head election, cluster affiliation and cluster management, and identifies new directions and recent trends in the design of these algorithms. Additionally, methodologies for validating clustering performance are reviewed, and a key shortcoming – the lack of realistic vehicular channel modelling – is identified. The importance of a rigorous and standardised performance evaluation regime utilising realistic vehicular channel models is demonstrated.
Corsetti, S, Rabl, T, McGloin, D & Kiefer, J 2017, 'Intermediate phases during solid to liquid transitions in long-chain n-alkanes', Physical Chemistry Chemical Physics, vol. 19, no. 21, pp. 13941-13950.
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Temperature-dependent Raman spectra of tetradecane, pentadecane and hexadecane are collected and analysed to unveil the difference in the speed of their phase transitions while gaining information about their structural changes.
Cui, Q, Gu, Y, Ni, W & Liu, RP 2017, 'Effective Capacity of Licensed-Assisted Access in Unlicensed Spectrum for 5G: From Theory to Application', IEEE Journal on Selected Areas in Communications, vol. 35, no. 8, pp. 1754-1767.
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© 1983-2012 IEEE. License-assisted access (LAA) is a promising technology to offload dramatically increasing cellular traffic to unlicensed bands. Challenges arise from the provision of quality-of-service (QoS) and the quantification of capacity, due to the distributed and heterogeneous nature of LAA and legacy systems (such as Wi-Fi) coexisting in the bands. In this paper, we develop new theories of the effective capacity to measure LAA under statistical QoS requirements. A new four-state semi-Markovian model is developed to capture transmission collisions, random backoffs, and lossy wireless channels of LAA in distributed heterogeneous network environments. A closed-form expression for the effective capacity is derived to comprehensively analyze LAA. The four-state model is further abstracted to an insightful two-state equivalent which reveals the concavity of the effective capacity in terms of transmit rate. Validated by simulations, the concavity is exploited to maximize the effective capacity and effective energy efficiency of LAA, and provide significant improvements of 62.7% and 171.4%, respectively, over existing approaches. Our results are of practical value to holistic designs and deployments of LAA systems.
Cui, Q, Yuan, T & Ni, W 2017, 'Energy-Efficient Two-Way Relaying Under Non-ideal Power Amplifiers', IEEE Transactions on Vehicular Technology, vol. 66, no. 2, pp. 1257-1270.
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© 2016 IEEE. Energy efficiency (EE) is crucial to many batterypowered relay applications. Maximizing EE is challenging due to non-convex structures resulting from non-ideal power amplifiers (PAs) and non-negligible circuit power. We formulate such non-convex problems to maximize the EE of two-way relay systems, where the transmit power and duration of all participating nodes are jointly optimized. The intrinsic connection between the optimal transmit power and duration is established through our derived necessary conditions of the optimality. It enables us to reformulate the non-convex problems to problems with rigorously proved convexity in the vicinities of the optimal transmit duration and to solve the problems using simple convex search. Simulation results show that the EE gain of our approach is substantial, compared with the state of the art, when the traffic demand is low or unbalanced in the two link directions. The gain enlarges as the imbalance of traffic demand grows.
Cui, Q, Zhang, Y, Ni, W, Valkama, M & Jantti, R 2017, 'Energy Efficiency Maximization of Full-Duplex Two-Way Relay With Non-Ideal Power Amplifiers and Non-Negligible Circuit Power', IEEE Transactions on Wireless Communications, vol. 16, no. 9, pp. 6264-6278.
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© 2002-2012 IEEE. In this paper, we maximize the energy efficiency (EE) of full-duplex (FD) two-way relay (TWR) systems under non-ideal power amplifiers (PAs) and non-negligible transmission-dependent circuit power. We start with the case where only the relay operates full duplex and two timeslots are required for TWR. Then, we extend to the advanced case, where the relay and the two nodes all operate full duplex, and accomplish TWR in a single timeslot. In both cases, we establish the intrinsic connections between the optimal transmit powers and durations, based on which the original non-convex EE maximization can be convexified and optimally solved. Simulations show the superiority of FD-TWR in terms of EE, especially when traffic demand is high. The simulations also reveal that the maximum EE of FD-TWR is more sensitive to the PA efficiency, than it is to self-cancellation. The full FD design of FD-TWR is susceptible to traffic imbalance, while the design with only the relay operating in the FD mode exhibits strong tolerance.
Ding, C, Jones, B, Guo, YJ & Qin, P-Y 2017, 'Wideband Matching of Full-Wavelength Dipole With Reflector for Base Station', IEEE Transactions on Antennas and Propagation, vol. 65, no. 10, pp. 5571-5576.
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© 1963-2012 IEEE. This communication introduces a wideband hybrid feeding method for full-wavelength dipole antennas with a reflector. A full-wavelength dipole is designed to cover the band from 698 to 960 MHz for cellular base station applications. Its matching circuit consists of a triple-tuned circuit and a quasi-quarter-wavelength impedance transformer. The proposed matching circuit can provide balanced feeding as a balun and has a compact size. The working mechanism and a complete design scheme of the proposed matching circuit are elaborated. The matching circuit is designed and optimized using a circuit theory model and then physically realized using microstrip lines based on full-wave simulation. The measured reflection coefficient |S-{11}| is lesser than -14 dB across the entire band from 698 to 960 MHz, exhibiting a bandwidth of 32%. This is the first time that a wideband center-fed full-wavelength dipole is proposed.
Ding, C, Sun, H, Ziolkowski, RW & Guo, YJ 2017, 'Simplified Tightly-Coupled Cross-Dipole Arrangement for Base Station Applications', IEEE Access, vol. 5, pp. 27491-27503.
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© 2013 IEEE. The electromagnetic fundamentals that govern the performance characteristics of dual-polarized tightly coupled cross-dipoles that are widely used in cellular base station applications are investigated. The mutual coupling effects and their impact on standard performance indices are stressed. A model is developed that considers this type of cross-dipole as an array. Links between the physical dimensions of the components of these model and key radiation characteristics, including directivity, half-power-beam width, and cross polarization discrimination levels, are established. The model guides the introduction and optimization of a simplified cross-dipole structure that exhibits excellent performance. A prototype was fabricated, assembled, and tested. The measured results are in good agreement with their simulated values, validating the model, and its governing principles.
Dorrell, DG, Salah, A & Guo, Y 2017, 'The Detection and Suppression of Unbalanced Magnetic Pull in Wound Rotor Induction Motors Using Pole-Specific Search Coils and Auxiliary Windings', IEEE Transactions on Industry Applications, vol. 53, no. 3, pp. 2066-2076.
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© 2017 IEEE. This paper puts forward a concept for measuring rotor eccentricity in a wound rotor induction machine. The analysis is fully developed in the theory section, then an experimental rig is described and measurements are taken. These are compared with the calculated values. Pole-specific search windings are necessary in a wound rotor machine, because standard sideband current measurement techniques are only valid for cage induction machines. The search coils can also be used to suppress unbalanced magnetic pull.
Du, J, Pegrum, CM, Gao, X, Weily, AR, Zhang, T, Guo, YJ & Foley, CP 2017, 'Harmonic Mixing Using a HTS Step-Edge Josephson Junction at 0.6 THz Frequency', IEEE Transactions on Applied Superconductivity, vol. 27, no. 4, pp. 1-5.
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© 2002-2011 IEEE. A high-temperature superconducting (HTS) terahertz (THz) heterodyne mixer based on a thin-film antenna-coupled YBa 2 Cu 3 O 7- x step-edge Josephson junction is presented. The frequency down-conversion from 0.6 THz to an intermediate frequency (IF) of 2 GHz was achieved using high-order harmonic mixing of a local oscillator (LO), thus removing the need to use a second THz source as the LO pumping source. The DC and RF characteristics of the harmonic mixer as well as the relationship of the IF output power versus the harmonic number were experimentally studied and compared with simulated results. Most of our measurements were made at 40 K, but we also observed stable harmonic mixing at 77 K which we believe has not been reported previously in HTS junction mixers.
Du, J, Weily, AR, Gao, X, Zhang, T, Foley, CP & Guo, YJ 2017, 'HTS step-edge Josephson junction terahertz harmonic mixer', Superconductor Science and Technology, vol. 30, no. 2, pp. 024002-024002.
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© 2016 Federal Australian Crown copyright. A high-temperature superconducting (HTS) terahertz (THz) frequency down-converter or mixer based on a thin-film ring-slot antenna coupled YBa 2 Cu 3 O 7-x (YBCO)/MgO step-edge Josephson junction is reported. The frequency down-conversion was achieved using higher order harmonics of an applied lower frequency (19-40 GHz) local oscillator signal in the Josephson junction mixing with a THz signal of over 600 GHz, producing a 1-3 GHz intermediate frequency signal. Up to 31st order of harmonic mixing was obtained and the mixer operated stably at temperatures up to 77 K. The design details of the antenna, HTS Josephson junction mixer, the matching and isolation circuits, and the DC and RF performance evaluation are described in this paper.
Duan, N, Xu, W, Li, Y, Wang, S, Guo, Y & Zhu, J 2017, 'Comparison of Limiting Loop Model and Elemental Operator Model for Magnetic Hysteresis of Ferromagnetic Materials', IEEE Transactions on Magnetics, vol. 53, no. 11, pp. 1-4.
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© 2017 IEEE. This paper introduces a comparative study of two different hysteresis models, limiting loop model and elemental operator model. The former is regarded as a mathematical approach based on the traditional Preisach model. To circumvent the difficulty of determining the distribution function in the Preisach model, the data of the limiting hysteresis loop and a function transform on the Preisach diagram are employed. The latter is a physical method which adopts a vectorial elemental operator with biaxial anisotropy based on the magnetization mechanisms of the ferromagnetic material. These two models are analyzed and compared in terms of the underlying principle, numerical implementation, and calculation accuracy in this paper. To verify the introduced models, the magnetic properties of non-oriented silicon steel Lycore-140 and soft magnetic composite material Somaloy 500 under alternating excitations are measured and compared with simulated results, which show the validity and practicability of the models but with different calculation accuracy and speed.
Duan, N, Xu, W, Wang, S & Zhu, J 2017, 'Accuracy analysis of structure with nearby interfaces within XFEM', AIP Advances, vol. 7, no. 5, pp. 056011-056011.
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This paper presents the fundamental principle of the extended finite element method (XFEM) for electromagnetic field analysis. The accuracy analysis of structure with nearby interfaces within XFEM is presented. A numerical example applied to the parallel plate electrodes in 1-D static electric field is provided. Two types of meshing are used to analyse the accuracy of the meshing where the support of the enriched node are cut by more than one interface.
Duan, N, Xu, W, Wang, S, Zhu, J, Qu, R & Jia, S 2017, 'A Temperature-Dependent Hysteresis Model for Soft Ferrites', IEEE Transactions on Magnetics, vol. 53, no. 6, pp. 1-4.
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© 1965-2012 IEEE. This paper introduces a temperature-dependent hysteresis model based on a vectorial elemental operator with temperature-sensitive spontaneous magnetization and biaxial anisotropy for the soft ferrites. Detailed analysis of the temperature-dependent magnetic properties of one elemental operator has been presented thereafter. With the help of the proposed vector elemental operator and the 2-D Gaussian distribution function, the temperature-dependent magnetic hysteresis of soft ferrites can be simulated. This model is validated by the substantial agreement between the simulated and measured major hysteresis loops of a soft ferrite sample Siemens 4C65 at different temperatures with slight acceptable error.
Edwards, D, Cheng, M, Wong, IA, Zhang, J & Wu, Q 2017, 'Ambassadors of knowledge sharing', International Journal of Contemporary Hospitality Management, vol. 29, no. 2, pp. 690-708.
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PurposeThe aim of this study is to understand the knowledge-sharing structure and co-production of trip-related knowledge through online travel forums.Design/methodology/approachThe travel forum threads were collected from TripAdvisor’s Sydney travel forum for the period from 2010 to 2014, which contains 115,847 threads from 8,346 conversations. The data analytical technique was based on a novel methodological approach – visual analytics, including semantic pattern generation and network analysis.FindingsFindings indicate that the knowledge structure is created by community residents who camouflage as local experts and serve as ambassadors of a destination. The knowledge structure presents collective intelligence co-produced by community residents and tourists. Further findings reveal how these community residents associate with each other and form a knowledge repertoire with information covering various travel domain areas.Practical implicationsThe study offers valuable insights to help destination-management organizations and tour operators identify existing and emerging tourism issues to achieve a competitive destination advantage.Originality/valueThis study highlights the process of social media mediated travel knowledge co-production. It also discovers how community residents engage in reaching out to tourists by camouflaging as ordinary users.
Every, J, Li, L & Dorrell, DG 2017, 'Leveraging smart meter data for economic optimization of residential photovoltaics under existing tariff structures and incentive schemes', Applied Energy, vol. 201, pp. 158-173.
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© 2017 Elsevier Ltd The introduction of smart grid technologies and the impending removal of incentive schemes is likely to complicate the cost-effective selection and integration of residential PV systems in the future. With the widespread integration of smart meters, consumers can leverage the high temporal resolution of energy consumption data to optimize a PV system based on their individual circumstances. In this article, such an optimization strategy is developed to enable the optimal selection of size, tilt, azimuth and retail electricity plan for a residential PV system based on hourly consumption data. Hourly solar insolation and PV array generation models are presented as the principal components of the underlying objective function. A net present value analysis of the potential monetary savings is considered and set as the optimization objective. A particle swarm optimization algorithm is utilized, modified to include a penalty function in order to handle associated constraints. The optimization problem is applied to real-world Australian consumption data to establish the economic performance and characteristics of the optimized systems. For all customers assessed, an optimized PV system producing a positive economic benefit could be found. However not all investment options were found to be desirable with at most 77.5% of customers yielding an acceptable rate of return. For the customers assessed, the mean PV system size was found to be 2 kW less than the mean size of actual systems installed in the assessed locations during 2015 and 2016. Over-sizing of systems was found to significantly reduce the potential net benefit of residential PV from an investor's perspective. The results presented in this article highlight the necessity for economic performance optimization to be routinely implemented for small-scale residential PV under current regulatory and future smart grid operating environments.
Fan, X, Xu, RYD, Cao, L & Song, Y 2017, 'Learning Nonparametric Relational Models by Conjugately Incorporating Node Information in a Network', IEEE Transactions on Cybernetics, vol. 47, no. 3, pp. 589-599.
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© 2013 IEEE. Relational model learning is useful for numerous practical applications. Many algorithms have been proposed in recent years to tackle this important yet challenging problem. Existing algorithms utilize only binary directional link data to recover hidden network structures. However, there exists far richer and more meaningful information in other parts of a network which one can (and should) exploit. The attributes associated with each node, for instance, contain crucial information to help practitioners understand the underlying relationships in a network. For this reason, in this paper, we propose two models and their solutions, namely the node-information involved mixed-membership model and the node-information involved latent-feature model, in an effort to systematically incorporate additional node information. To effectively achieve this aim, node information is used to generate individual sticks of a stick-breaking process. In this way, not only can we avoid the need to prespecify the number of communities beforehand, the algorithm also encourages that nodes exhibiting similar information have a higher chance of assigning the same community membership. Substantial efforts have been made toward achieving the appropriateness and efficiency of these models, including the use of conjugate priors. We evaluate our framework and its inference algorithms using real-world data sets, which show the generality and effectiveness of our models in capturing implicit network structures.
Farrok, O, Islam, MR, Sheikh, MRI, Guo, YG & Zhu, JG 2017, 'Design and Analysis of a Novel Lightweight Translator Permanent Magnet Linear Generator for Oceanic Wave Energy Conversion', IEEE Transactions on Magnetics, vol. 53, no. 11, pp. 1-4.
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© 1965-2012 IEEE. At present, most of the linear generators contain a heavy translator for converting wave power from the ocean into electrical power. As the translator is connected to the buoy, the buoy dynamic performance is reduced by the large mass and, as a result, low velocity of the translator would degrade the electricity generation of the linear generator. This problem has been minimized by the new design in this paper, where the translator is clipped off at first and split into two separate portions to minimize its weight. The secondary stator is magnetically coupled with a special m-shaped main stator which is used to flow the necessary magnetic flux. The weight of the proposed translator is 21.82% lower than that of conventional one and 49.1% by using a recently available permanent magnet with higher specifications. The finite-element method is applied in ANSYS simulation environment for the analysis and comparison between the proposed and conventional designs. Different parameters of the conventional and the proposed linear generator have been discussed in this paper. The simulation results show that the proposed design can generate the same amount of electricity as the existing one with almost half of the translator size. According to the mathematical model, it is understood that the dynamics of the translator would be higher for its lower mass and vice versa. Therefore, minimizing the translator size would result in decrease of mass, which increases the dynamics of the buoy connected to the translator.
Fontugne, R, Abry, P, Fukuda, K, Veitch, D, Cho, K, Borgnat, P & Wendt, H 2017, 'Scaling in Internet Traffic: A 14 Year and 3 Day Longitudinal Study, With Multiscale Analyses and Random Projections', IEEE/ACM Transactions on Networking, vol. 25, no. 4, pp. 2152-2165.
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© 2017 IEEE. In the mid 1990s, it was shown that the statistics of aggregated time series from Internet traffic departed from those of traditional short range-dependent models, and were instead characterized by asymptotic self-similarity. Following this seminal contribution, over the years, many studies have investigated the existence and form of scaling in Internet traffic. This contribution first aims at presenting a methodology, combining multiscale analysis (wavelet and wavelet leaders) and random projections (or sketches), permitting a precise, efficient and robust characterization of scaling, which is capable of seeing through non-stationary anomalies. Second, we apply the methodology to a data set spanning an unusually long period: 14 years, from the MAWI traffic archive, thereby allowing an in-depth longitudinal analysis of the form, nature, and evolutions of scaling in Internet traffic, as well as network mechanisms producing them. We also study a separate three-day long trace to obtain complementary insight into intra-day behavior. We find that a biscaling (two ranges of independent scaling phenomena) regime is systematically observed: long-range dependence over the large scales, and multifractallike scaling over the fine scales. We quantify the actual scaling ranges precisely, verify to high accuracy the expected relationship between the long range dependent parameter and the heavy tail parameter of the flow size distribution, and relate fine scale multifractal scaling to typical IP packet inter-arrival and to round-trip time distributions.
Forouzesh, M, Siwakoti, YP, Gorji, SA, Blaabjerg, F & Lehman, B 2017, 'Step-Up DC–DC Converters: A Comprehensive Review of Voltage-Boosting Techniques, Topologies, and Applications', IEEE Transactions on Power Electronics, vol. 32, no. 12, pp. 9143-9178.
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© 1986-2012 IEEE. DC-DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which fundamental energy storing elements (inductors and capacitors) and/or transformers in conjunction with switch(es) and diode(s) are utilized in the circuit. These techniques include switched capacitor (charge pump), voltage multiplier, switched inductor/voltage lift, magnetic coupling, and multistage/-level, and each has its own merits and demerits depending on application, in terms of cost, complexity, power density, reliability, and efficiency. To meet the growing demand for such applications, new power converter topologies that use the above voltage-boosting techniques, as well as some active and passive components, are continuously being proposed. The permutations and combinations of the various voltage-boosting techniques with additional components in a circuit allow for numerous new topologies and configurations, which are often confusing and difficult to follow. Therefore, to present a clear picture on the general law and framework of the development of next-generation step-up dc-dc converters, this paper aims to comprehensively review and classify various step-up dc-dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc-dc converters are presented and summarized with comparative study of different voltage-boosting techniques.
Gadalla, BS, Schaltz, E, Siwakoti, Y & Blaabjerg, F 2017, 'Analysis of loss distribution of Conventional Boost, Z-source and Y-source Converters for wide power and voltage range', Transactions on Environment and Electrical Engineering, vol. 2, no. 1, pp. 1-1.
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Boost converters are needed in many applications which require the output voltage to be higher than the input voltage. Recently, boost type converters have been applied for industrial applications, and hence it has become an interesting topic of research. Many researchers proposed different impedance source converters with their unique advantages as having a high voltage gain in a small range of duty cycle ratio. However, the thermal behaviour of the semiconductor devices and passive elements in the impedance source converter is an important issue from a reliability point of view and it has not been investigated yet. Therefore, this paper presents a comparison between the conventional boost, the Z-source, and the Y-source converters based on a thermal evaluation of the semiconductors. In addition, the three topologies are also compared with respect to their efficiency. In this study the results show that the boost converter has higher efficiency than the Zsource and Y-source converter for these specific voltage gain of 2 and 4. The operational principle, mathematical derivations, simulation results and final comparisons are presented in this paper.
Gao, H, Wu, B, Xu, D, Aguilera, RP & Acuna, P 2017, 'Model Predictive Switching Pattern Control for Current-Source Converters With Space-Vector-Based Selective Harmonic Elimination', IEEE Transactions on Power Electronics, vol. 32, no. 8, pp. 6558-6569.
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© 2017 IEEE. This paper presents a model predictive switching pattern control (MPSPC) for a current-source converter (CSC), which achieves superb low-order harmonics elimination performance in steady state and improved transient responses. Based on a proposed space-vector-based selective harmonic elimination (SHE) method and prediction of load current at the next sampling instant, MPSPC prefers to following a precalculated SHE-pulse width modulation (PWM) pattern in steady state, and governing the CSC through a model predictive control (MPC) approach during transients. In comparison with existing schemes, the advantages of MPSPC are threefold: First, quantization error, introduced by a constant sampling frequency in MPC and degrading steady-state low-order harmonic elimination, is mitigated in the proposed scheme. Second, there is no weighting factor in the cost function, as used in existing schemes. Finally, MPSPC is totally realized based on one-step prediction, which simplifies the structure of the scheme. Both simulation and experimental results verify the steady state and dynamic performance of MPSPC with different SHE-PWM patterns.
Gao, H, Wu, B, Xu, DD, Pande, M & Aguilera, RP 2017, 'Model predictive control scheme with active damping function for current source rectifiers', IET Power Electronics, vol. 10, no. 7, pp. 717-725.
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© The Institution of Engineering and Technology. This study presents a model predictive control (MPC) with active damping function for current-source rectifiers (CSRs). Since optimal modulating vector selection process of MPC leads to spread harmonic distribution in pulse-width-modulated (PWM) waveform, inductor-capacitor (LC) resonance can be easily excited. Conventional MPC was designed without the consideration of active damping, since it is for low-power CSRs with large line resistors physically connected inside the circuit, whereas the proposed scheme achieves active damping function through a specially developed cost function, which realizes active damping function even for high-power CSRs with lightly damped LC circuit. In comparison with conventional MPC, the advantages of the proposed scheme are three-fold: first, the proposed scheme is totally based on MPC concept, without conventional linear controller used. Second, with the active damping term added in the developed cost function, active damping effect can be involved into MPC, which extends MPC to high-power CSRs with lightly damped LC circuit. Last but not least, the proposed scheme is realized in the dq-axis synchronous frame, which allows the use of simple low-pass filters instead of complex band-stop filters to obtain the damping current.
Gao, X, Du, J, Zhang, T & Guo, YJ 2017, 'Noise and conversion performance of a high-Tc superconducting Josephson junction mixer at 0.6 THz', Applied Physics Letters, vol. 111, no. 19, pp. 192603-192603.
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This letter presents both theoretical and experimental investigations on the noise and conversion performance of a high-Tc superconducting (HTS) step-edge Josephson-junction mixer at the frequency of 0.6 THz and operating temperatures of 20–40 K. Based on the Y-factor and U-factor methods, a double-sideband noise temperature of around 1000 K and a conversion gain of −3.5 dB were experimentally obtained at 20 K. At the temperature of 40 K, the measured mixer noise and conversion efficiency are around 2100 K and −10 dB, respectively. The experimental data are in good agreement with the numerical analysis results using the three-port model. A detailed performance comparison with other reported HTS terahertz mixers has confirmed the superior performance of our presented mixer device.
Gao, X, Du, J, Zhang, T, Jay Guo, Y & Foley, CP 2017, 'Experimental Investigation of a Broadband High-Temperature Superconducting Terahertz Mixer Operating at Temperatures Between 40 and 77 K', Journal of Infrared, Millimeter, and Terahertz Waves, vol. 38, no. 11, pp. 1357-1367.
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© 2017, Springer Science+Business Media, LLC. This paper presents a systematic investigation of a broadband thin-film antenna-coupled high-temperature superconducting (HTS) terahertz (THz) harmonic mixer at relatively high operating temperature from 40 to 77 K. The mixer device chip was fabricated using the CSIRO established step-edge YBa 2 Cu 3 O 7-x (YBCO) Josephson junction technology, packaged in a well-designed module and cooled in a temperature adjustable cryocooler. Detailed experimental characterizations were carried out for the broadband HTS mixer at both the 200 and 600 GHz bands in harmonic mixing mode. The DC current-voltage characteristics (IVCs), bias current condition, local oscillator (LO) power requirement, frequency response, as well as conversion efficiency under different bath temperatures were thoroughly investigated for demonstrating the frequency down-conversion performance.
Gao, X, Zhang, T, Du, J, Weily, AR, Guo, YJ & Foley, CP 2017, 'A wideband terahertz high-Tcsuperconducting Josephson-junction mixer: electromagnetic design, analysis and characterization', Superconductor Science and Technology, vol. 30, no. 9, pp. 095011-095011.
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© 2017 IOP Publishing Ltd. This paper presents a wideband terahertz (THz) mixer based on a thin-film antenna-coupled high-temperature superconducting (HTS) YBa 2 Cu 3 O 7-x (YBCO) step-edge Josephson junction. The HTS mixer enables the flexible harmonic mixing operation at multiple THz bands with the same microwave local oscillator (LO) source, and features very wide intermediate-frequency or instantaneous bandwidth. In order to optimize the frequency down-conversion performance of the mixer, systematic electromagnetic design and analysis have been carried out to improve the power coupling of THz radiation as well as wideband transmission of microwave signals. Experimental characterization of a fabricated device prototype has demonstrated that the mixer exhibits good performance at both the 200 GHz and 600 GHz bands. Detailed measurement results including the DC characteristics, LO pumping requirement, frequency response, mixing linearity and conversion gain are presented in this paper.
Golsorkhi, MS, Lu, DD-C & Guerrero, JM 2017, 'A GPS-Based Decentralized Control Method for Islanded Microgrids', IEEE Transactions on Power Electronics, vol. 32, no. 2, pp. 1615-1625.
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Golsorkhi, MS, Savaghebi, M, Lu, DD-C, Guerrero, JM & Vasquez, JC 2017, 'A GPS-Based Control Framework for Accurate Current Sharing and Power Quality Improvement in Microgrids', IEEE Transactions on Power Electronics, vol. 32, no. 7, pp. 5675-5687.
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© 1986-2012 IEEE.This paper proposes a novel hierarchical control strategy for improvement of load sharing and power quality in ac microgrids. This control framework is composed of a droop based controller at the primary level, and a combination of distributed power sharing and voltage conditioning schemes at the secondary level. The controllers in the primary level use GPS timing technology to synchronize the local reference angles. The voltage reference of each Distributed Generation (DG) is adjusted according to a voltage-current (V-I) droop characteristic to enable proper current and power sharing with a fast dynamic response. The droop coefficient, which acts as a virtual resistance is adaptively changed as a function of the peak current. This strategy not only simplifies the control design but also improves the current sharing accuracy at high loading conditions. The distributed power sharing scheme uses consensus protocol to ensure proportional sharing of average power. The voltage conditioning scheme produces compensation signals at fundamental and dominant harmonics to improve the voltage quality at a sensitive load bus. Experimental results are presented to validate the efficacy of the proposed method.
Golsorkhi, MS, Shafiee, Q, Lu, DD-C & Guerrero, JM 2017, 'A Distributed Control Framework for Integrated Photovoltaic-Battery-Based Islanded Microgrids', IEEE Transactions on Smart Grid, vol. 8, no. 6, pp. 2837-2848.
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This paper proposes a new cooperative control framework for coordination of energy storage units (ESUs), photovoltaic (PV) panels, and controllable load units in single-phase low voltage microgrids (MGs). The control objectives are defined and acted upon using a two level structure; primary and secondary control. Unlike conventional methods, a V-I droop mechanism is utilized in the primary control level. A distributed strategy is introduced for the secondary control level to regulate the MG voltage and manage state of charge (SoC) and power among the ESUs. The distributed secondary controllers are coordinated based on a leader-follower framework, where the leader restores the MG voltage to the rated value and the followers manage the sharing of power between the ESUs so as to balance the SoCs. Once the ESUs reach the minimum charge level, the information state increases above a positive critical value, at which point load control units perform load shedding. Similarly, fair PV curtailment is conducted in case the ESUs reach the maximum charge level. Experimental results are presented to demonstrate the efficacy of the proposed method.
Guan, Q, Cheng, J, Li, X, Ni, W & Wang, B 2017, 'Porous CoF2 Spheres Synthesized by a One‐Pot Solvothermal Method as High Capacity Cathode Materials for Lithium‐Ion Batteries', Chinese Journal of Chemistry, vol. 35, no. 1, pp. 48-54.
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AbstractUp to now, there are rare reports of CoF2 spheres used as high capacity cathode materials. Herein, porous CoF2 spheres were synthesized and studied as cathode materials for LIBs. The porous CoF2 spheres were synthesized by a facile one‐pot solvothermal method using a safe and inexpensive ammonium fluoride as the fluorine sources. The nature of the synthesis can avoid using corrosive fluorine sources and additional high‐temperature thermal treatment. The structure, morphologies and electrochemical performance of the samples obtained at different reaction times and solvothermal temperatures were investigated. The results show that the CoF2 spheres obtained at 200 °C for 20 h show better electrochemical performances, including a high initial discharge capacity, good capacity retention and high Coulombic efficiency. It can deliver a high initial discharge capacity of 537.8 mA•h•g−1 and keep 127.4 mA•h•g−1 after 30 cycles used as cathode materials for lithium‐ion batteries. The good electrochemical performances may be attributed to good crystallinity, porous structure and relatively intermediate sphere size.
Guo, B, Huang, Y, Peng, F, Guo, Y & Zhu, J 2017, 'Analytical Modeling of Manufacturing Imperfections in Double-Rotor Axial Flux PM Machines: Effects on Back EMF', IEEE Transactions on Magnetics, vol. 53, no. 6, pp. 1-5.
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© 1965-2012 IEEE. In this paper, a general analytical model is proposed to calculate the back electromotive forces of various manufacturing imperfections in the double-rotor axial flux permanent magnet machine. First, the axial and circumferential flux density in the air gap under healthy condition is developed by Maxwell's equations and Schwarz-Christoffel mapping. Second, the equations of air gap length and radii are introduced to calculate the flux density with manufacturing imperfections. The back EMFs of each case are calculated. For each case, finite-element (FE) method models are developed to validate the analytical model, and the results show that the analytical model predictions match well with the FE results. Finally, the analytical model is verified by experimental results.
Guo, D, Xu, J, Zhang, J, Xu, M, Cui, Y & He, X 2017, 'User relationship strength modeling for friend recommendation on Instagram', Neurocomputing, vol. 239, pp. 9-18.
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© 2017 Elsevier B.V. Social strength modeling in the social media community has attracted increasing research interest. Different from Flickr, which has been explored by many researchers, Instagram is more popular for mobile users and is conducive to likes and comments but seldom investigated. On Instagram, a user can post photos/videos, follow other users, comment and like other users’ posts. These actions generate diverse forms of data that result in multiple user relationship views. In this paper, we propose a new framework to discover the underlying social relationship strength. User relationship learning under multiple views and the relationship strength modeling are coupled into one process framework. In addition, given the learned relationship strength, a coarse-to-fine method is proposed for friend recommendation. Experiments on friend recommendations for Instagram are presented to show the effectiveness and efficiency of the proposed framework. As exhibited by our experimental results, it can obtain better performance over other related methods. Although our method has been proposed for Instagram, it can be easily extended to any other social media communities.
Habibkhah, S, Ghiyasi, M, Arasi, J & Li, L 2017, 'Parameters Identification of Industrial Induction Motor Using Manufacturer Data Sheet and Power Quality Analyzer', International Review of Automatic Control (IREACO), vol. 10, no. 4, pp. 341-341.
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© 2017 Praise Worthy Prize S.r.l. - All rights reserved. This paper intends to identify circuit parameters of an installed induction motor in an innovative way which is different from standard tests. In this paper, easily available motor manufacturer data is used by which rated output power, rated terminal voltage, full load efficiency, full load power factor, nominal speed, number of poles, and locked rotor current are provided. In order to estimate the parameters, nonlinear mathematical equations of motor are derived and iterative Gauss-Seidel method is used to solve them in MATLAB. Identified parameters are then transferred to MATLAB/Simulink model of the motor to simulate its performance during Star-Delta start. Validation of parameters is evaluated by comparing the result of Simulink with real-time measurement of an industrial Power Quality Analyzer.
Habibullah, M, Lu, DD, Xiao, D, Fletcher, JE & Rahman, MF 2017, 'Low complexity predictive torque control strategies for a three‐level inverter driven induction motor', IET Electric Power Applications, vol. 11, no. 5, pp. 776-783.
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© The Institution of Engineering and Technology. Iterative and complex prediction loop is a challenge for the implementation of finite-state predictive torque control (FS-PTC) of motor drive. The complexity is due to the complex torque calculations, number of available voltage vectors (which are called as prediction vectors), and weighting factor tuning for torque and flux errors in the cost function. One way to reduce the complexity is an equivalent reference stator flux vector calculation (RSFVC) from torque and flux references, which also solves the problem of weighting factor tuning. Along with a new stator flux based RSFVC technique, a reduced number of prediction vectors are proposed in this study to reduce the number of iteration of the prediction loop. The position of the stator flux and sign of the stator flux-error are considered to lessen the number of prediction vectors. Hence, the implementation challenges of FS-PTC algorithm are overcome. The performance of the proposed technique is investigated for two types of RSFVCs: one is based on the stator flux, and another one is based on the rotor flux. Experimental results verify that the proposed low complexity FS-PTC strategies retain the advantages of a conventional FS-PTC.
Habibullah, M, Lu, DD-C, Xiao, D & Rahman, MF 2017, 'Finite-State Predictive Torque Control of Induction Motor Supplied From a Three-Level NPC Voltage Source Inverter', IEEE Transactions on Power Electronics, vol. 32, no. 1, pp. 479-489.
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© 2016 IEEE. Finite-state predictive torque control (FS-PTC) of an induction motor (IM) drive has been widely investigated for two-level voltage source inverter recently. This control method suffers from high and variable switching frequencies in a wide range, due to the limited number of available voltage vectors of the power converter. In order to take advantage of multilevel inverter drives which offer the benefits of low harmonic distortion of the stator currents, torque ripple, and low switching frequency, this paper proposes the integration of the FS-PTC with a three-level neutral-point clamped (3L-NPC) inverter driven IM drive. The drawback inherited from the topology of 3L-NPC voltage source inverter (VSI), such as neutral-point voltage, is easily handled by treating it as a variable to the cost function. Similarly, apart from the inverter topology itself, the average switching frequency is reduced further, and is maintained almost constant over a wide speed range. The effectiveness of the proposed FS-PTC in terms of torque and flux responses, capacitor voltage balancing, and low average switching frequency is validated through experimental results.
Habibullah, M, Lu, DD-C, Xiao, D, Fletcher, JE & Rahman, MF 2017, 'Predictive Torque Control of Induction Motor Sensorless Drive Fed by a 3L-NPC Inverter', IEEE Transactions on Industrial Informatics, vol. 13, no. 1, pp. 60-70.
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© 2016 IEEE.A finite-state predictive torque control system for a speed-sensorless induction motor drive supplied from a threelevel neutral-point clamped inverter is proposed. For sensorless operation, the controller requires estimated speed and rotor/stator flux. In this study, the rotor speed and the rotor flux are estimated accurately by using an extended Kalman filter. Due to the large number of available voltage vectors, the control algorithm for a multi-level inverter-fed drive is computationally expensive. As a consequence, the controller requires longer execution time that yields worse torque, flux, and speed responses, especially at low-speed. In order to reduce the computational burden, a reduced number of voltage vectors for prediction and optimization in the control algorithm is proposed in this paper. The sign of the stator flux deviation and the position of the stator flux are predicted to lessen the number of voltage vectors tested. Experimental results illustrate that the proposed encoderless strategy can estimate the speed accurately over a wide speed range including field-weakening region while maintaining robustness and excellent torque and flux responses.
Habibullah, M, Lu, DD-C, Xiao, D, Osman, I & Rahman, MF 2017, 'Selected Prediction Vectors Based FS-PTC for 3L-NPC Inverter Fed Motor Drives', IEEE Transactions on Industry Applications, vol. 53, no. 4, pp. 3588-3597.
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© 1972-2012 IEEE. Computational burden is a major hurdle for practical implementation of finite-state predictive torque control (FS-PTC) of motor drive fed by a multilevel inverter. One of the reasons of computational complexity is that all voltage vectors are evaluated for prediction and actuation. This paper proposes a reduced number of voltage vectors for the prediction and actuation, which are called prediction vectors in FS-PTC. The performance is investigated for a three-level neutral-point clamped inverter fed motor drive in terms of torque and flux response, stator current total harmonic distortion, robustness, average switching frequency, and neutral-point voltage variation. The number of prediction vectors is reduced based on the position of stator flux and the deviation in stator flux from its reference. Experimental results confirm that the computational burden could be reduced by 38%, while the dynamic performance is comparable with the conventional all voltage vectors based FS-PTC.
Han, L, Ou, X, Du, J, Han, X & Guo, Y 2017, 'Study of Direct Coupling in Stator Dual Windings of a Brushless Doubly Fed Machine', IEEE Transactions on Energy Conversion, vol. 32, no. 3, pp. 974-982.
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© 1986-2012 IEEE. A brushless doubly fed machine (BDFM) usually contains two sets of independent three-phase symmetrical stator windings. Judgment of the direct electromagnetic coupling phenomenon between the two sets of stator windings is one of the most important prerequisites when safeguarding the excellent operation and control performances of the BDFM. However, because of the diversity among the stator winding structures, the generation mechanism and the existing criterion of direct coupling between the two sets of stator windings have not been fully revealed yet. This paper analyzes the mutually induced electromotive force (EMF) in the coils per pole per phase of a single stator winding that is induced by the rotating magnetic field of the other stator winding. Detailed studies of the effects of the winding structures on the mutually induced EMF and the circulating current are performed and the results are verified by finite element analysis and experimental studies of an existing BDFM prototype. The results show that the direct coupling between the two sets of stator windings is related to the combination of poles number, the number of parallel branches, the winding type, and the winding connection.
Hoang, DT, Niyato, D, Wang, P, Kim, DI & Han, Z 2017, 'Ambient Backscatter: A New Approach to Improve Network Performance for RF-Powered Cognitive Radio Networks', IEEE Transactions on Communications, vol. 65, no. 9, pp. 3659-3674.
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© 1972-2012 IEEE. This paper introduces a new solution to improve the performance for secondary systems in radio frequency (RF) powered cognitive radio networks (CRNs). In a conventional RF-powered CRN, the secondary system works based on the harvest-then-transmit protocol. That is, the secondary transmitter (ST) harvests energy from primary signals and then uses the harvested energy to transmit data to its secondary receiver (SR). However, with this protocol, the performance of the secondary system is much dependent on the amount of harvested energy as well as the primary channel activity, e.g., idle and busy periods. Recently, ambient backscatter communication has been introduced, which enables the ST to transmit data to the SR by backscattering ambient signals. Therefore, it is potential to be adopted in the RF-powered CRN. We investigate the performance of RF-powered CRNs with ambient backscatter communication over two scenarios, i.e., overlay and underlay CRNs. For each scenario, we formulate and solve the optimization problem to maximize the overall transmission rate of the secondary system. Numerical results show that by incorporating such two techniques, the performance of the secondary system can be improved significantly compared with the case when the ST performs either harvest-then-transmit or ambient backscatter technique.
Hoang, DT, Wang, P, Niyato, D & Hossain, E 2017, 'Charging and Discharging of Plug-In Electric Vehicles (PEVs) in Vehicle-to-Grid (V2G) Systems: A Cyber Insurance-Based Model', IEEE Access 2017, vol. 5, pp. 732-754.
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In addition to being environment-friendly, vehicle-to-grid (V2G) systems canhelp the plug-in electric vehicle (PEV) users in reducing their energy costsand can also help stabilizing energy demand in the power grid. In V2G systems,since the PEV users need to obtain system information (e.g., locations ofcharging/discharging stations, current load and supply of the power grid) toachieve the best charging and discharging performance, data communication playsa crucial role. However, since the PEV users are highly mobile, informationfrom V2G systems is not always available for many reasons, e.g., wireless linkfailures and cyber attacks. Therefore, in this paper, we introduce a novelconcept using cyber insurance to 'transfer' cyber risks, e.g., unavailableinformation, of a PEV user to a third party, e.g., a cyber insurance company.Under the insurance coverage, even without information about V2G systems, a PEVuser is always guaranteed the best price for charging/discharging. Inparticular, we formulate the optimal energy cost problem for the PEV user byadopting a Markov decision process framework. We then propose a learningalgorithm to help the PEV user make optimal decisions, e.g., to charge ordischarge and to buy or not to buy insurance, in an online fashion. Throughsimulations, we show that cyber insurance is an efficient solution not only indealing with cyber risks, but also in maximizing revenue of the PEV user.
Hoang, TM, Duong, TQ, Tuan, HD & Poor, HV 2017, 'Secure Massive MIMO Relaying Systems in a Poisson Field of Eavesdroppers', IEEE Transactions on Communications, vol. 65, no. 11, pp. 4857-4870.
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© 1972-2012 IEEE. A cooperative relay network operating in the presence of eavesdroppers, whose locations are distributed according to a homogeneous Poisson point process, is considered. The relay is equipped with a very large antenna array and can exploit maximal ratio combing in the uplink and maximal ratio transmission in the downlink. A realistic model in which the channel state information of every eavesdropper is not known is considered, as eavesdroppers tend to hide themselves in practice. The destination is thus in a much weaker position than all the eavesdroppers because it only receives the retransmitted signal from the relay. Under this setting, the security performance is investigated for two relaying protocols: amplify-and-forward and decode-and-forward. The secrecy outage probability, the connection outage probability, and the tradeoff between them, which is controlled by the source power allocation, are examined. Finally, suitable solutions for the source power (such that once the transmission occurs with high reliability, the secure risk is below a given threshold) are proposed for a tradeoff between security and reliability.
Hosoe, S, Tuan, HD & Nguyen, TN 2017, '2D Bilinear programming for robust PID/DD controller design', International Journal of Robust and Nonlinear Control, vol. 27, no. 3, pp. 461-482.
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© 2016 John Wiley & Sons, Ltd.A new design method of PID structured controllers to achieve robust performance is developed. Both robust stabilization and performance conditions are losslessly expressed by bilinear constraints in the proportional-double derivative variable (kP,kDD) and the integral-derivative variable (kI,kD). Therefore, the considered control design can be efficiently solved by alternating optimization between (kP,kDD) and (kI,kD), which is a 2D computationally tractable program. The proposed method works equally efficiently whenever even higher order differential or integral terms are included in PID control to improve its robustness and performance. Numerical examples are provided to show the viability of the proposed development.
Hossain, M, Pota, H, Issa, W & Hossain, M 2017, 'Overview of AC Microgrid Controls with Inverter-Interfaced Generations', Energies, vol. 10, no. 9, pp. 1300-1300.
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Hossain, MA, Pota, HR, Haruni, AMO & Hossain, MJ 2017, 'DC-link voltage regulation of inverters to enhance microgrid stability during network contingencies', Electric Power Systems Research, vol. 147, pp. 233-244.
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Hu, H, Zhao, J, Liu, X, Guo, Y & Zhu, J 2017, 'No-Load Magnetic Field and Cogging Force Calculation in Linear Permanent-Magnet Synchronous Machines With Semiclosed Slots', IEEE Transactions on Industrial Electronics, vol. 64, no. 7, pp. 5564-5575.
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© 2017 IEEE. This paper presents an improved analytical subdomain model for predicting the magnetic field in linear permanent magnet synchronous machines (LPMSMs) with semiclosed slots accounting for the finite length of primary iron core and secondary back-iron. The whole field domain is divided into eight subdomains and the magnetic field in each subdomain is solved by applying the variable separation method, adequate boundary conditions, and interface conditions. In this model, both the slot and end effects are considered. The thrust and normal forces are calculated by the Maxwell stress theory. The finite element analysis is carried out to validate the analytical model. Finally, an LPMSM prototype is manufactured and tested. The experimental results show that the developed analytical model has high accuracy for predicting the magnetic field and forces.
Hu, Y, Zhang, J, Li, P, Yu, D & Jiang, L 2017, 'Non-Uniform Aged Modules Reconfiguration for Large-Scale PV Array', IEEE Transactions on Device and Materials Reliability, vol. 17, no. 3, pp. 560-569.
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In the past decades, a large number of photovoltaic (PV) plants have been built. Due to the minor physical differences between PV cells and the influence of environmental factors such as rains, temperature, and humidity, the aging of a PV array is often distributed unevenly within each PV module. This non-uniform aging causes further decreased output power, which is often easily observed for large size PV arrays. Although the global maximum power point tracking (GMPPT) strategy can improve the output power, the GMPPT cannot exploit the maximal power generation potential from non-uniform aging PV arrays. In order to exploit further the power generation potential and extend the service time of non-uniform aging PV arrays, a novel PV array reconfiguration method is developed in this paper. The concept of cell unit is applied to investigate the aging phenomenon of PV modules, and each PV module is assumed to be composed of three submodules, while these three submodules within any single PV module might have different aging conditions and, thus, different power-output capacities. The challenge is how to rearrange the PV array under the cases where: 1) each PV module has non-uniformly aged cell units; 2) there are a large number of PV modules; and 3) the voltage working range is restricted. To solve these problems, a nonlinear integer programming problem is formulated to maximize the power output under the constraints of non-uniformly aging and voltage restrictions. A small size 7 x 10 PV array is simulated to illustrate the proposed method. Furthermore, medium size 20 x 10 and large size 125 x 20 PV arrays are employed to verify the feasibility of the proposed method. A 1.5 kW 2 x 4 real PV array under non-uniform aging conditions is presented and experimentally tested to confirm the proposed rearrangement method.
Hu, Y, Zheng, K, Wang, X & Yang, Y 2017, 'WORM-HUNTER: A Worm Guard System using Software-defined Networking', KSII Transactions on Internet and Information Systems, vol. 11, no. 1, pp. 484-510.
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Huang, J, Lin, W, Qiu, F, Jiang, C, Lei, D & Guo, YJ 2017, 'A Low Profile, Ultra-Lightweight, High Efficient Circularly-Polarized Antenna Array for Ku Band Satellite Applications', IEEE Access, vol. 5, pp. 18356-18365.
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© 2013 IEEE. A novel low-profile, ultra-lightweight, high-efficient circularly polarized (CP) planar patch antenna array is reported for Ku-band satellite TV reception applications. The basic radiating element of the antenna array is realized by a $2 \times 2$ corner-removed patch subarray. This $2 \times 2$ patch subarray is center-fed by a rectangular coupling aperture etched on the top surface of a substrate-integrated-waveguide cavity. A novel compact sequential rotation feeding technique is adopted to broaden the operating bandwidth without occupying additional area. The $2 \times 2$ CP subarray can be easily scaled up for large size antenna arrays due to its single layer feeding network and compact radiating elements. In addition, the patch radiators are printed on a thin layer of Polyimide film backed by a piece of supporting foam to minimize the entire weight. To verify the design concept, a 96-element ( $16 \times 6$ ) CP patch array was fabricated and tested. Measured results show that the operating bandwidth is 700 MHz from 11.55 to 12.25 GHz. The gain is stable across the operating bandwidth with a realized peak gain of 26.4 dBic. The height of the antenna is $0.05~\lambda {0}$ and the total weight is only 66.5 g. It serves as an excellent candidate for Ku-band satellite applications.
Huang, J, Qiu, F, Lin, W, Tang, Z, Lei, D, Yao, M, Chu, Q-X & Guo, YJ 2017, 'A New Compact and High Gain Circularly-Polarized Slot Antenna Array for Ku-Band Mobile Satellite TV Reception', IEEE Access, vol. 5, pp. 6707-6714.
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Huang, S, Zhang, J, Schonfeld, D, Wang, L & Hua, X-S 2017, 'Two-Stage Friend Recommendation Based on Network Alignment and Series Expansion of Probabilistic Topic Model', IEEE Transactions on Multimedia, vol. 19, no. 6, pp. 1314-1326.
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© 2017 IEEE. Precise friend recommendation is an important problem in social media. Although most social websites provide some kinds of auto friend searching functions, their accuracies are not satisfactory. In this paper, we propose a more precise auto friend recommendation method with two stages. In the first stage, by utilizing the information of the relationship between texts and users, as well as the friendship information between users, we align different social networks and choose some 'possible friends.' In the second stage, with the relationship between image features and users, we build a topic model to further refine the recommendation results. Because some traditional methods, such as variational inference and Gibbs sampling, have their limitations in dealing with our problem, we develop a novel method to find out the solution of the topic model based on series expansion. We conduct experiments on the Flickr dataset to show that the proposed algorithm recommends friends more precisely and faster than traditional methods.
Huang, X & Guo, YJ 2017, 'Radio Frequency Self-Interference Cancellation With Analog Least Mean-Square Loop', IEEE Transactions on Microwave Theory and Techniques, vol. 65, no. 9, pp. 3336-3350.
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© 1963-2012 IEEE. A multitap adaptive filter with analog least mean-square (ALMS) loop is proposed in this paper for effective and low complexity self-interference cancellation implemented as part of the radio frequency frontend in a full duplex transceiver. Comprehensive analyses of the ALMS loop's behaviors at both micro and macroscales are presented for a wireless communication system with single carrier signaling. It is revealed that there is always an irreducible residual interference due to the cyclostationary property of the transmitted signal. The interference suppression ratio (ISR) lower bound is derived accordingly, which can be used as a design rule for determining the ALMS loop parameter. Stationary analysis shows that the convergence speed and achievable ISR of the ALMS loop are determined by the loop gain and the autocorrelation function of the transmitted signal. The interference channel modeling error with the adaptive filter also accounts for part of the residual interference power. These theoretical findings are verified by simulation and experimental results.
Huang, Y, Guo, B, Guo, Y, Zhu, J, Hemeida, A & Sergeant, P 2017, 'Analytical modeling of axial flux PM machines with eccentricities', International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 4, pp. 757-777.
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Huangfu, Y, Wang, S, Di Rienzo, L & Zhu, J 2017, 'Radiated EMI Modeling and Performance Analysis of a PWM PMSM Drive System Based on Field-Circuit Coupled FEM', IEEE Transactions on Magnetics, vol. 53, no. 11, pp. 1-4.
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© 2017 IEEE. The radiated electromagnetic interference (EMI) behavior may have a negative impact on the machining accuracy of grinding machines. Therefore, this paper focuses on the radiated EMI generated by an ultra-precision pulsewidth modulation permanent-magnet synchronous motor (PMSM) drive system. The excitation for the radiated EMI model, the common-mode (CM) ground current at the output terminal of the converter, is obtained by simulating its conducted EMI model. The reasonable simplified FE models for the converter frame, the shielded power cable, and the motor frame are established. In addition, an equivalent circuit macro model of the CM impedance of the three-phase PMSM windings is obtained by using impedance measurements, the vector fitting method, and the fast residue perturbation method. Finally, the 3-D time harmonic field-circuit coupled finite-element method is employed to evaluate the radiated EMI.
Hussein, F & Piccardi, M 2017, 'V-JAUNE', ACM Transactions on Multimedia Computing, Communications, and Applications, vol. 13, no. 2, pp. 1-19.
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Video summarization and action recognition are two important areas of multimedia video analysis. While these two areas have been tackled separately to date, in this article, we present a latent structural SVM framework to recognize the action and derive the summary of a video in a joint, simultaneous fashion. Efficient inference is provided by a submodular score function that accounts for the action and summary jointly. In this article, we also define a novel measure to evaluate the quality of a predicted video summary against the annotations of multiple annotators. Quantitative and qualitative results over two challenging action datasets—the ACE and MSR DailyActivity3D datasets—show that the proposed joint approach leads to higher action recognition accuracy and equivalent or better summary quality than comparable approaches that perform these tasks separately.
Huynh, NV, Hoang, DT, Lu, X, Niyato, D, Wang, P & Kim, DI 2017, 'Ambient Backscatter Communications: A Contemporary Survey', IEEE Communications Surveys and Tutorials, vol. 20, no. 4, pp. 2889-2922.
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Recently, ambient backscatter communications has been introduced as acutting-edge technology which enables smart devices to communicate by utilizingambient radio frequency (RF) signals without requiring active RF transmission.This technology is especially effective in addressing communication and energyefficiency problems for low-power communications systems such as sensornetworks. It is expected to realize numerous Internet-of-Things (IoT)applications. Therefore, this paper aims to provide a contemporary andcomprehensive literature review on fundamentals, applications, challenges, andresearch efforts/progress of ambient backscatter communications. In particular,we first present fundamentals of backscatter communications and briefly reviewbistatic backscatter communications systems. Then, the general architecture,advantages, and solutions to address existing issues and limitations of ambientbackscatter communications systems are discussed. Additionally, emergingapplications of ambient backscatter communications are highlighted. Finally, weoutline some open issues and future research directions.
Imran Azim, M, Hossain, J & Pota, H 2017, 'Design of Droop-based Control for Power Management in Islanded RL-type Microgrids', International Journal of Emerging Electric Power Systems, vol. 18, no. 2.
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AbstractThis paper proposes a new type of generalized droop-based proportional power sharing scheme during load change for parallel inverter-interfaced islanded microgrids, which is an automatic strategy and is independent of any particular nature of transmission lines, i.e., resistive or inductive. Real and reactive powers are shared in proportion to the droop gains by implementing the voltage control law proposed in this paper; in which the inverter-interfaced voltage-sources are kept at equal reference values. The control gains are chosen based on eigenvalue analysis in a way that the system stability is ascertained. The performance of the designed controller is simulated under different microgrid structures such as load variation and various types of transmission lines; in which the results show superior dynamic performance in comparison to the conventional droop-based control strategy.
Islam, MR, Mahfuz-Ur-Rahman, AM, Islam, MM, Guo, YG & Zhu, JG 2017, 'Modular Medium-Voltage Grid-Connected Converter With Improved Switching Techniques for Solar Photovoltaic Systems', IEEE Transactions on Industrial Electronics, vol. 64, no. 11, pp. 8887-8896.
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© 1982-2012 IEEE. The high-frequency common magnetic-link made of amorphous material, as a replacement for common dc-link, has been gaining considerable interest for the development of solar photovoltaic medium-voltage converters. Even though the common magnetic-link can almost maintain identical voltages at the secondary terminals, the power conversion system loses its modularity. Moreover, the development of high-capacity high-frequency inverter and power limit of the common magnetic-link due to leakage inductance are the main challenging issues. In this regard, a new concept of identical modular magnetic-links is proposed for high-power transmission and isolation between the low and the high voltage sides. Third harmonic injected sixty degree bus clamping pulse width modulation and third harmonic injected thirty degree bus clamping pulse width modulation techniques are proposed which show better frequency spectra as well as reduced switching loss. In this paper, precise loss estimation method is used to calculate switching and conduction losses of a modular multilevel cascaded converter. To ensure the feasibility of the new concepts, a reduced size of 5 kVA rating, three-phase, five-level, 1.2 kV converter is designed with two 2.5 kVA identical high-frequency magnetic-links using Metglas magnetic alloy-based cores.
Jafari, M, Malekjamshidi, Z, Lei, G, Wang, T, Platt, G & Zhu, J 2017, 'Design and Implementation of an Amorphous High-Frequency Transformer Coupling Multiple Converters in a Smart Microgrid', IEEE Transactions on Industrial Electronics, vol. 64, no. 2, pp. 1028-1037.
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© 1982-2012 IEEE. Recent improvements in magnetic material characteristics and switching devices have generated a possibility to replace the electrical buses with high-frequency magnetic links in microgrids. Multiwinding transformers (MWTs) as magnetic links can effectively reduce the number of conversion stages of renewable energy system by adjusting turn ratio of windings according to the source voltage level. Other advantages are galvanic isolation, bidirectional power flow capability, and simultaneous power transfer between multiple ports. Despite the benefits, design, and characterization of MWTs are relatively complex due to their structural complexity and cross-coupling effects. This paper presents all stages of numerical design, prototyping, and characterization of an MWT for microgrid application. To design the transformer for certain value of parameters, the reluctance network method is employed. Due to the iterative nature of transformer design, it presented less computation time and reasonable accuracy. A prototype of designed transformer is implemented using amorphous magnetic materials. A set of experimental tests are conducted to measure the magnetic characteristics of the core and series coupling and open-circuit tests are applied to measure the transformer parameters. A comparison between the simulation and experimental test results under different loads within the medium-frequency range validated both design and modeling procedures.
Jan, M, Nanda, P, Usman, M & He, X 2017, 'PAWN: a payload‐based mutual authentication scheme for wireless sensor networks', Concurrency and Computation: Practice and Experience, vol. 29, no. 17, pp. e3986-e3986.
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SummaryWireless sensor networks (WSNs) consist of resource‐starving miniature sensor nodes deployed in a remote and hostile environment. These networks operate on small batteries for days, months, and even years depending on the requirements of monitored applications. The battery‐powered operation and inaccessible human terrains make it practically infeasible to recharge the nodes unless some energy‐scavenging techniques are used. These networks experience threats at various layers and, as such, are vulnerable to a wide range of attacks. The resource‐constrained nature of sensor nodes, inaccessible human terrains, and error‐prone communication links make it obligatory to design lightweight but robust and secured schemes for these networks. In view of these limitations, we aim to design an extremely lightweight payload‐based mutual authentication scheme for a cluster‐based hierarchical WSN. The proposed scheme, also known as payload‐based mutual authentication for WSNs, operates in 2 steps. First, an optimal percentage of cluster heads is elected, authenticated, and allowed to communicate with neighboring nodes. Second, each cluster head, in a role of server, authenticates the nearby nodes for cluster formation. We validate our proposed scheme using various simulation metrics that outperform the existing schemes.
Jauregi, I, Solar, H, Beriain, A, Zalbide, I, Jimenez, A, Galarraga, I & Berenguer, R 2017, 'UHF RFID Temperature Sensor Assisted With Body-Heat Dissipation Energy Harvesting', IEEE Sensors Journal, vol. 17, no. 5, pp. 1471-1478.
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Jia, Y, Liu, Y, Guo, YJ, Li, K & Gong, S 2017, 'A Dual-Patch Polarization Rotation Reflective Surface and Its Application to Ultra-Wideband RCS Reduction', IEEE Transactions on Antennas and Propagation, vol. 65, no. 6, pp. 3291-3295.
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© 2017 IEEE. An ultra-wideband polarization rotation reflective surface (PRRS) with a high polarization conversion ratio (PCR) is proposed, which can reflect a linearly polarized incident wave with 90° polarization rotation. The unit cell of the proposed PRRS consists of a square and L-shaped patches printed on a substrate, which is covered by a superstrate and backed by a metallic ground. The two patches are connected to the ground using two metallic vias, respectively. Compared with the previously reported PRRS, the polarization rotation bandwidth of the proposed PRRS is enhanced from 49% to 97% with a high PCR of 96%. The frequency responses within the operation frequency band are consistent under oblique incident waves. Furthermore, the designed PRRS is applied to the ultra-wideband radar cross-section (RCS) reduction by forming a checkerboard surface. A 10-dB RCS reduction is achieved over an ultrawideband of 98%. To validate the simulation results, a prototype of the checkerboard surface is fabricated and measured. A good agreement between the experimental and simulation results is obtained.
Kamal, MS & Nimmy, SF 2017, 'StrucBreak: A Computational Framework for Structural Break Detection in DNA Sequences', Interdisciplinary Sciences: Computational Life Sciences, vol. 9, no. 4, pp. 512-527.
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Kamal, MS, Chowdhury, L, Khan, MI, Ashour, AS, Tavares, JMRS & Dey, N 2017, 'Hidden Markov model and Chapman Kolmogrov for protein structures prediction from images', Computational Biology and Chemistry, vol. 68, pp. 231-244.
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Kamal, MS, Parvin, S, Ashour, AS, Shi, F & Dey, N 2017, 'De-Bruijn graph with MapReduce framework towards metagenomic data classification', International Journal of Information Technology, vol. 9, no. 1, pp. 59-75.
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Karmokar, DK, Guo, YJ, Qin, P-Y, Esselle, KP & Bird, TS 2017, 'Forward and Backward Beam-Scanning Tri-Band Leaky-Wave Antenna', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 1891-1894.
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© 2002-2011 IEEE. The main limitations of uniform half-width microstrip leaky-wave antennas (HW-MLWAs), namely a single operating band and only forward beam scanning, are overcome here with an HW-MLWA loaded with periodic L-shaped slots. The antenna exhibits tri-band operation, and the main beam can be steered in the forward direction in one band, and in the backward direction in the other two bands. Its size is halved with a shorting wall. The antenna was fabricated and tested to validate the concept, and the measured and simulated results agree very well. The measured matched (10-dB return loss) bandwidths of the prototype are 22.34% (5.05-6.32 GHz), 15.85% (8.77-10.28 GHz), and 11.21% (12.63-14.13 GHz) in the first, second, and third bands, respectively. The beam-scanning ranges of the prototyped antenna are 30° to 64°, -75° to -18°, and -19° to -4° when the frequency sweeps from 5 to 6 GHz, 8.85 to 10.5 GHz, and 13 to 14.25 GHz, respectively. The measured peak gains (within the scanning range) are 12.4, 14.3, and 14.7 dBi in the first, second, and third bands with variations of 2.5, 3.4, and 3.1 dB, respectively.
Keshavarz, R, Mohammadi, A & Abdipour, A 2017, 'A linearity improved quad-band amplifier based on E-CRLH transmission line', International Journal of Microwave and Wireless Technologies, vol. 9, no. 8, pp. 1603-1610.
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This paper outlines a new class of quad-band amplifier (QBA) realized using extended composite right- and left-handed coupled lines. The design procedure to reach the QB CLs with predefined frequency operations and characteristic impedance of their ports is clearly presented. Designed and fabricated QBA operation frequencies are$f_{b_{1}} = 2.9\,GHz$and${\rm \;} f_{b_2} = 4.3\,GHz$(output port B)${\bi \;} \; f_{f_1} = 3.8\,GHz\; $and$\; \; f_{f_2} = 5\,GHz\; $(output port C) and the proposed structure exhibits a matching (−10 dB) bandwidth of over 300 MHz in each operation frequency bands. In addition, the insertion loss is smaller than 1 dB. The length and the width of the proposed QBA are approximately 7.7 and 2.4 cm, respectively. To further demonstrate the idea, a QBA is successfully designed and fabricated. The simulated and measured results of the proposed QBA are presented to verify the proposed idea.
Khan, ZH, Kermany, AR, Öchsner, A & Iacopi, F 2017, 'Mechanical and electromechanical properties of graphene and their potential application in MEMS', Journal of Physics D: Applied Physics, vol. 50, no. 5, pp. 053003-053003.
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� 2017 IOP Publishing Ltd. Graphene-based micro-electromechanical systems (MEMS) are very promising candidates for next generation miniaturized, lightweight, and ultra-sensitive devices. In this review, we review the progress to date of the assessment of the mechanical, electromechanical, and thermomechanical properties of graphene for application in graphene-based MEMS. Graphene possesses a plethora of outstanding properties - such as a 1 TPa Young's modulus, exceptionally high 2D failure strength that stems from its sp 2 hybridization, and strong sigma bonding between carbon atoms. Such exceptional mechanical properties can enable, for example, graphene-based sound sources capable of generating sound beyond the audible range. The recently engineered piezoelectric properties of atomic force microscope tip-pressed graphene membranes or supported graphene on SiO 2 substrates, have paved the way in fabricating graphene-based nano-generators and actuators. On the other hand, graphene's piezoresistive properties have enabled miniaturized pressure and strain sensors. 2D graphene nano-mechanical resonators can potentially measure ultralow forces, charges and potentially detect single atomic masses. The exceptional tribology of graphene can play a significant role in achieving superlubricity. In addition, the highest reported thermal conductivity of graphene is amenable for use in chips and providing better performing MEMS, as heat is efficiently dissipated. On top of that, graphene membranes could be nano-perforated to realize specialized applications like DNA translocation and desalination. Finally, to ensure stability and reliability of the graphene-based MEMS, adhesion is an important mechanical property that should be considered. In general, graphene could be used as a structural material in resonators, sensors, actuators and nano-generators with better performance and sensitivity than conventional MEMS.
Kong, F, Sun, X, Guo, YJ & Zhu, H 2017, 'Queue-Aware Optimal Bandwidth Allocation in Heterogeneous Networks', IEEE Wireless Communications Letters, vol. 6, no. 6, pp. 730-733.
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© 2017 IEEE. This letter considers how to allocate the bandwidth to multiple radio access technologies (RATs) in heterogeneous networks. In contrast to previous studies where base stations (BSs) are assumed to be transmitting all the time, it is assumed that the incoming packets from users form a queue in each BS. A minimization problem of the network average power consumption and a maximization problem of the network signalto- interference ratio coverage are formulated, which are shown to be convex and concave with respect to the bandwidth allocation to each RAT, respectively. By using an approximation of the average traffic intensity, closed-form solutions are obtained for both problems.
Kovaleva, M, Bulger, D, Zeb, BA & Esselle, KP 2017, 'Cross-Entropy Method for Electromagnetic Optimization With Constraints and Mixed Variables', IEEE Transactions on Antennas and Propagation, vol. 65, no. 10, pp. 5532-5540.
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Lalbakhsh, A, Afzal, MU & Esselle, KP 2017, 'Multiobjective Particle Swarm Optimization to Design a Time-Delay Equalizer Metasurface for an Electromagnetic Band-Gap Resonator Antenna', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 912-915.
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This letter presents an efficient particle swarm optimization (PSO) algorithm developed to design a near-field time-delay equalizer metasurface (TDEM) for the purpose of improving directivity and radiation patterns of classical electromagnetic band-gap resonator antennas. Triple layers of conductive printed patterns in the metasurface were optimized by the PSO algorithm to systematically design the TDEM. Predicted and measured results show a significant improvement in antenna performance including 9.6 dB enhancement in antenna directivity, lower sidelobes, and higher gain. The measured directivity of the prototype is 21 dBi, and 3-dB bandwidth is 11.8%.
Le, NT & Hoang, DB 2017, 'Capability Maturity Model and Metrics Framework for Cyber Cloud Security', Scalable Computing: Practice and Experience, vol. 18, no. 4, pp. 277-290.
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Lee, D, van Dorp Schuitman, J, Cabrera, D, Qiu, X & Burnett, I 2017, 'Comparison of psychoacoustic-based reverberance parameters', The Journal of the Acoustical Society of America, vol. 142, no. 4, pp. 1832-1840.
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This study compared psychoacoustic reverberance parameters to each other, as well as to reverberation time (RT) and early decay time (EDT) under various acoustic conditions. The psychoacoustic parameters were loudness-based RT (TN), loudness-based EDT [EDTN; Lee, Cabrera, and Martens, J. Acoust. Soc. Am. 131, 1194–1205 (2012a)], and parameter for reverberance [PREV; van Dorp Schuitman, de Vries, and Lindau., J. Acoust. Soc. Am. 133, 1572–1585 (2013)]. For the comparisons, a wide range of sound pressure levels (SPLs) from 20 dB to 100 dB and RTs from 0.5 s to 5.0 s were evaluated, and two sets of subjective data from the previous studies were used for the cross-validation and comparison. Results of the comparisons show that the psychoacoustic reverberance parameters provided better matches to reverberance than RT and EDT; however, the performance of these psychoacoustic reverberance parameters varied with the SPL range, the type of audio sample, and the reverberation conditions. This study reveals that PREV is the most relevant for estimating a relative change in reverberance between samples when the SPL range is small, while EDTN is useful in estimating the absolute reverberance. This study also suggests the use of PREV and EDTN for speech and music samples, respectively.
Lei, G, Zhu, J, Guo, Y, Liu, C & Ma, B 2017, 'A Review of Design Optimization Methods for Electrical Machines', Energies, vol. 10, no. 12, pp. 1962-1962.
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© 2017 by the authors. Licensee MDPI, Basel, Switzerland. Electrical machines are the hearts of many appliances, industrial equipment and systems. In the context of global sustainability, they must fulfill various requirements, not only physically and technologically but also environmentally. Therefore, their design optimization process becomes more and more complex as more engineering disciplines/domains and constraints are involved, such as electromagnetics, structural mechanics and heat transfer. This paper aims to present a review of the design optimization methods for electrical machines, including design analysis methods and models, optimization models, algorithms and methods/strategies. Several efficient optimization methods/strategies are highlighted with comments, including surrogate-model based and multi-level optimization methods. In addition, two promising and challenging topics in both academic and industrial communities are discussed, and two novel optimization methods are introduced for advanced design optimization of electrical machines. First, a system-level design optimization method is introduced for the development of advanced electric drive systems. Second, a robust design optimization method based on the design for six-sigma technique is introduced for high-quality manufacturing of electrical machines in production. Meanwhile, a proposal is presented for the development of a robust design optimization service based on industrial big data and cloud computing services. Finally, five future directions are proposed, including smart design optimization method for future intelligent design and production of electrical machines.
Li, B, Chen, S, Sutton, GJ, Shi, Y & Liu, RP 2017, 'MAC Performance Analysis for Drive-Thru Internet Networks With Rayleigh Capture', IEEE Access, vol. 5, pp. 10649-10661.
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© 2013 IEEE. In practical radio transmissions, channel capture is a dominating factor that affects wireless network performance. The capture effect can occur in wireless network when packets arrive with different powers. Packets with high power can effectively swamp low power packets, such that they are received successfully, when otherwise a collision would have occurred. We present a vehicular network performance-prediction model for a Rayleigh capture channel in Drive-thru Internet scenario. The model incorporates the capture effect into a 2-D Markov chain modeling the high-node mobility and distributed coordination function broadcast scheme. The performance-prediction model unveils the impacts of mobility velocity and number of vehicles on the throughput in a Rayleigh capture channel. We use a vehicular traffic flow model to predict vehicular movement on road by aggregating all vehicles into a flow. Simulation results confirm that our performance-prediction model accurately predicts the performance of traveling vehicles with Rayleigh capture channel in the Drive-thru Internet scenario. We demonstrate that using our performance-prediction model, we can obtain optimal contention window value, by which the best system throughput can be reached without wasting contention time. This is also proved by Anastasi et al.
Li, B, Sutton, GJ, Hu, B, Liu, RP & Chen, S 2017, 'Modeling and QoS analysis of the IEEE 802.11p broadcast scheme in vehicular ad hoc networks', Journal of Communications and Networks, vol. 19, no. 2, pp. 169-179.
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© 2011 KICS. Quality of service (QoS) and queue management are critical issues for the broadcast scheme of IEEE 802.11p systems in vehicular ad hoc networks (VANETs). However, existing 1-dimensional (1-D) Markov chain models of 802.11p systems are unable to capture the complete QoS performance and queuing behavior due to the lack of an adequate finite buffer model. We present a 2-dimensional (2-D) Markov chain that integrates the broadcast scheme of the 802.11p system and the queuing process into one model. The extra dimension, which models the queue length, allows us to accurately capture the important QoS measures, delay and loss, plus throughput and queue length, for realistic 802.11p systems with finite buffer under finite load. We derive a simplified method to solve the steady state probabilities of the 2-D Markov chain. Our 2-D Markov chain model is the first finite buffer model defined and solved for the broadcast scheme of 802.11p systems. The 2-D model solutions are validated by extensive simulations. Our analyses reveal that the lack of binary exponential backoff and retransmission in the 802.11p system results in poor QoS performance during heavy traffic load, particularly for large VANETs. We demonstrate that our model provides traffic control guidelines to maintain good QoS performance for VANETs.
Li, B, Zhao, J, Liu, X, Guo, Y, Hu, H & Li, J 2017, 'Detent Force Reduction of an Arc-Linear Permanent-Magnet Synchronous Motor by Using Compensation Windings', IEEE Transactions on Industrial Electronics, vol. 64, no. 4, pp. 3001-3011.
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© 2016 IEEE. An arc-linear permanent-magnet synchronous machine (AL-PMSM) is a kind of servo machine used for a scanning system to meet the requirements of high positioning accuracy, high response performance, and wide scanning range. To reduce the detent force and increase the travel range of the AL-PMSM, a novel hybrid excited AL-PMSM with a normal armature winding and compensation windings is proposed and investigated. The compensation windings are installed on the end teeth of the primary side. The influence of a compensation direct current is analyzed by a finite element method (FEM). Based on the result of the analysis, a proper compensation current is proposed to reduce the detent force. The result after the compensation is simulated by the FEM. In addition, a combination of primary length optimization and current compensation is proposed, the proper formula for the compensation current is deduced, and the result calculated by the FEM is provided. To reduce the detent force of the travel end, a proper current is supplied into the compensation winding, the detent force during the both end of the travel range is much reduced, so the smooth travel range is increased. Finally, prototypes of AL-PMSM are manufactured and experiments are conducted to validate the proposed compensation method.
Li, H & Huang, X 2017, 'Multicast Systems With Fair Scheduling in Non-identically Distributed Fading Channels', IEEE Transactions on Vehicular Technology, vol. 66, no. 10, pp. 8835-8844.
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© 1967-2012 IEEE. Multicasting is emerging as an efficient method to deliver the same data to a group of users, thereby saving network resources. The fairness between different multicast groups is an important quality-of-service (QoS) indication, but it has not been given significant attention. In this paper, we propose a normalized signal-To-noise ratio (SNR)-based fair scheduling for multiple multicast groups in multicast systems. The system fairness and capacity are then analyzed and compared for both fair scheduling and greedy scheduling over independent but non-identically distributed (i.n.d.) fading channels. Closed-form expressions in terms of the system spectral efficiency, outage probability, system fairness, and average bit error rate (BER) are derived in an uncoded/coded M-Ary quadrature amplitude modulation based adaptive transmission multicast system over i.n.d. Rayleigh fading channels. Numerical results show that compared with greedy scheduling, fair scheduling achieves considerably high fairness at the cost of slight system capacity loss, regardless of the number of multicast groups. Our focus is on the physical layer without rate loss, but we also briefly discuss applications of the proposed scheduling in a cross-layer design subject to the loss rate QoS constraint.
Li, J, Deng, C, Da Xu, RY, Tao, D & Zhao, B 2017, 'Robust Object Tracking With Discrete Graph-Based Multiple Experts', IEEE Transactions on Image Processing, vol. 26, no. 6, pp. 2736-2750.
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© 1992-2012 IEEE. Variations of target appearances due to illumination changes, heavy occlusions, and target deformations are the major factors for tracking drift. In this paper, we show that the tracking drift can be effectively corrected by exploiting the relationship between the current tracker and its historical tracker snapshots. Here, a multi-expert framework is established by the current tracker and its historical trained tracker snapshots. The proposed scheme is formulated into a unified discrete graph optimization framework, whose nodes are modeled by the hypotheses of the multiple experts. Furthermore, an exact solution of the discrete graph exists giving the object state estimation at each time step. With the unary and binary compatibility graph scores defined properly, the proposed framework corrects the tracker drift via selecting the best expert hypothesis, which implicitly analyzes the recent performance of the multi-expert by only evaluating graph scores at the current frame. Three base trackers are integrated into the proposed framework to validate its effectiveness. We first integrate the online SVM on a budget algorithm into the framework with significant improvement. Then, the regression correlation filters with hand-crafted features and deep convolutional neural network features are introduced, respectively, to further boost the tracking performance. The proposed three trackers are extensively evaluated on three data sets: TB-50, TB-100, and VOT2015. The experimental results demonstrate the excellent performance of the proposed approaches against the state-of-the-art methods.
Li, K, Liu, Y, Jia, Y & Guo, YJ 2017, 'A Circularly Polarized High-Gain Antenna With Low RCS Over a Wideband Using Chessboard Polarization Conversion Metasurfaces', IEEE Transactions on Antennas and Propagation, vol. 65, no. 8, pp. 4288-4292.
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© 1963-2012 IEEE. A new approach for the gain enhancement and wideband radar cross section (RCS) reduction of an antenna based on the chessboard polarization conversion metasurfaces (CPCMs) is proposed. Compared with the previous low-RCS antennas, high gain and wideband low RCS of a circularly polarized (CP) antenna are achieved simultaneously. The proposed CPCM is the chessboard configuration of the polarization conversion metasurfaces (PCMs), which is made up of adjoining two-layer substrates with three metallic patterns. Low RCS is realized by 180° (±30°) reflection phase variations between two neighboring PCMs. Gain enhancement is achieved by employing a Fabry-Perot cavity, which is constructed by the PCM and the ground of the antenna. The antenna with CPCM operating at the X -band, excited by a sequentially rotated feeding network, is fabricated and measured. Simulated and measured results show that the left-hand CP gain of the antenna with CPCM is at least 3 dB higher than that of the reference antenna from 8.5 to 9.5 GHz and the monostatic RCS is effectively reduced from 6 to 14 GHz.
Li, W, Xu, KD, Tang, X, Yang, Y, Liu, Y & Liu, QH 2017, 'Substrate Integrated Waveguide Cavity-Backed Slot Array Antenna Using High-Order Radiation Modes for Dual-Band Applications in $K$ -Band', IEEE Transactions on Antennas and Propagation, vol. 65, no. 9, pp. 4556-4565.
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© 2017 IEEE. A novel compact dual-band cavity-backed substrate integrated waveguide (SIW) array antenna using high-order radiation modes has been proposed in this paper. The first high-order hybrid mode (superposition of TM310 and TM130) and the second high-order mode (TM320) of K-band in the SIW cavity are excited by an inductive window for dual-band application. The operation mechanism of high-order modes is analyzed and then verified through simulations by inserting metallic vias in different positions of the resonant SIW cavity. The designed subarray antenna has the advantages of high gain, high front-to-back ratio, and low cross-polarization level. To further validate the design idea, a dual-frequency band $2 \times 2$ array antenna has been fabricated and measured including reflection coefficients, realized gains, and radiation patterns. The measured results show that the 10-dB impedance bandwidths at resonant frequencies of 21 and 26 GHz are 800 MHz (3.7%) and 700 MHz (2.6%), and the realized gains at boresight direction are around 16 and 17.4 dBi, respectively. Moreover, the proposed array antenna also possesses both advantages of metallic cavity-backed antennas and planar patch antennas, such as low cost, easy fabrication with the printed circuit board technology, and integration with other planar circuits.
Li, X, Fang, L, Lu, Z, Zhang, J & Zhao, H 2017, 'A Line Flow Granular Computing Approach for Economic Dispatch With Line Constraints', IEEE Transactions on Power Systems, vol. 32, no. 6, pp. 4832-4842.
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Line flow calculation plays a critically important role to guarantee the stable operation of power system in economic dispatch (ED) problems with line constraints. This paper presents a line flow granular computing approach for power flow calculation to assist the investigation on ED with line constraints, where the hierarchy method is adopted to divide the power network into multiple layers to reduce computational complexity. Each layer contains granules for granular computing, and the layer network is reduced by Ward equivalent retaining the PV nodes and boundary nodes of tie lines to decrease the data dimension. Then, Newton-Raphson method is applied further to calculate the power line flows within the layer. This approach is tested on IEEE 39-bus and 118-bus systems. The testing results show that the granular computing approach can solve the line flow problem in 9.2 s for the IEEE 118-bus system, while the conventional AC method needs 44.56 s. The maximum relative error of the granular computing approach in line flow tests is only 0.43%, which is quite small and acceptable. Therefore, the case studies demonstrate that the proposed granular computing approach is correct, effective, and can ensure the accuracy and efficiency of power line flow calculation.
Li, X, Xu, W, Ye, C & Zhu, J 2017, 'Novel Hybrid-Flux-Path Moving-Iron Linear Oscillatory Machine With Magnets on Stator', IEEE Transactions on Magnetics, vol. 53, no. 11, pp. 1-5.
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Li, Y, Geng, X, Zhang, C, Yan, R & Zhu, J 2017, 'Improved 3-D Magnetic Properties Measurement of Silicon Steel Laminations Based on a Novel Sensing Structure', IEEE Transactions on Magnetics, vol. 53, no. 11, pp. 1-4.
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© 1965-2012 IEEE. The precise 3-D magnetic property measurement of the silicon steel is important to improve the efficiency and performance in electrical equipment, such as electrical machines and power transformers. An improved 3-D magnetic property measurement method of the silicon steel laminations is proposed by using a novel sensing structure with interconnecting multiple sensing coils covered on the surface of the cubic specimen. Based on the new coil structure with high precise coefficients from comprehensive calibration, the accurate relationship between B and H vectors is obtained and analyzed under alternating and 3-D rotating excitations with the feedback control method, especially when the laminated direction is considered. Consequently, the experimental data of magnetic properties with high precision can be obtained, which can provide important reference in designing and optimizing electrical equipment.
Li, Y, Wang, L, Yang, Q, Zhu, J & Zhang, C 2017, 'Comprehensive magnetic properties measurement of the laminated silicon steel by 3-D magnetic tester', International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. S1, pp. 177-191.
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© 2017 - IOS Press and the authors. All rights reserved. In this paper, a novel three-dimensional (3-D) magnetic tester with symmetrical orthogonal excitation structure and cubic field-metric sensing structure is designed and analyzed. Automatic measurement system, which includes feedback control method, harmonics compensation, and automatic data processing is developed for the 3-D magnetic tester. In order to improve the measurement precision, cross effects of the magnetic fields in three principal directions are concerned, and error mitigation methods which fit for different excitation models are proposed. Magnetic properties of typical grain-oriented (GO) and non-grain-oriented (NGO) laminated silicon steel specimens under alternating and rotating excitations are measured and analyzed by using the designed 3-D magnetic tester.
Liang, J, Su, S, Zhang, X, Li, L & Luo, Y 2017, 'A NONINVASIVE METHOD TO EVALUATE THE DEGREE OF UPPER AIRWAY STENOSIS', Biomedical Engineering: Applications, Basis and Communications, vol. 29, no. 05, pp. 1750035-1750035.
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Purpose: This paper presented a new approach to noninvasively evaluate the upper airway stenosis for obstructive sleep apnea syndrome (OSAS) patients. Methods: In the proposed method, thoracic and abdominal movements were selected to calculate the respiratory movement (RM) and to indicate the change of lung volume. Due to the cumulative effect of thermal sensor, the oronasal-thermistor signal (T_flow) is applied to estimate the air mass change in lung. Based on the mathematical relationship, the “RM–T_flow curves”, drawn by RM and T_flow, together with the correlation coefficients ([Formula: see text] were used to analyze the upper airway stenosis. Results: This method was verified through portable monitoring (PM) based experiments, and numerical analysis of the polysomnography (PSG) data from 20 OSAS patients and 15 non-OSAS controls. Our results indicate the [Formula: see text] values decrease with the narrowing of the upper airway. At each sleep stage, the [Formula: see text] mean values of OSAS subjects are significantly ([Formula: see text]) smaller than those of the controls. These facts demonstrate that the [Formula: see text] value can be used to quantify the upper airway stenosis and the analysis of “RM–T_flow curves” is an efficient way to assess upper airway condition associated with the breathing phase. Conclusions: As this method can be used in spontaneous sleep and home sleep testing, we believe it will benefit the popularity of the diagnosis and evaluation of OSAS.
Ling, SH, San, PP, Lam, HK & Nguyen, HT 2017, 'Hypoglycemia detection: multiple regression-based combinational neural logic approach', Soft Computing, vol. 21, no. 2, pp. 543-553.
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© 2015 Springer-Verlag Berlin Heidelberg Hypoglycemia is a common and serious side effect of type 1 diabetes. We measure physiological parameters continuously to provide detection of hypoglycemic episodes in type 1 diabetes mellitus patients using a multiple regression-based combinational neural logic approach. In this work, a neural logic network with multiple regression is applied to the development of non-invasive hypoglycemia monitoring system. It is an alarm system which measures the physiological parameters of electrocardiogram signal (heart rate and corrected QT interval) and determine the onset of hypoglycemia by the use of proposed hybrid neural logic approach. In this clinical application, a combinational neural logic network with multiple regression is systematically designed to hypoglycemia detection based on the characteristic of this application. To optimize the parameter of the hybrid combinational neural logic system, hybrid particle swarm optimization with wavelet mutation is applied to tuned the parameters of the system. To illustrate the effectiveness of the proposed method, hypoglycemia monitoring system which will be practically analyzed using real data sets collected from 15 children ((Formula presented.) years) with type 1 diabetes at the Department of Health, Government of Western Australia. With the use of proposed method, the best testing sensitivity of 79.07 % and specificity of 53.64 % were obtained.
Ling, Y, Li, C, Feng, K, Palmer, S, Appleton, PL, Lang, S, McGloin, D, Huang, Z & Nabi, G 2017, 'Second harmonic generation (SHG) imaging of cancer heterogeneity in ultrasound guided biopsies of prostate in men suspected with prostate cancer', Journal of Biophotonics, vol. 10, no. 6-7, pp. 911-918.
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Prostate cancer is a multifocal disease with characteristic heterogeneity and foci that can range from low grade indolent to aggressive disease. The latter is characterised by the well‐established histopathological Gleason grading system used in the current clinical care. Nevertheless, a large discrepancy exists on initial biopsy and after the final radical prostatectomy. Moreover, there is no reliable imaging modality to study these foci, in particular at the level of the cells and surrounding matrix. Extracellular matrix (ECM) remodelling is significant in cancer progression with collagen as the dominant structural component providing mechanical strength and flexibility of tissue. In this study, the collagen assembly in prostate tissue was investigated with second harmonic generation (SHG) microscopy: malignant foci demonstrated a reticular pattern, with a typical collagen pattern for each Gleason score. The orientation of collagen for each biopsy was computed by applying a ratio of the anisotropic and isotropic collagen fibres. This value was found to be distinct for each Gleason score. The findings suggest that this approach can not only be used to detect prostate cancer, but also can act as a potential biomarker for cancer aggressiveness.magnified image
Liu, C, Lei, G, Ma, B, Wang, Y, Guo, Y & Zhu, J 2017, 'Development of a New Low-Cost 3-D Flux Transverse Flux FSPMM With Soft Magnetic Composite Cores and Ferrite Magnets', IEEE Transactions on Magnetics, vol. 53, no. 11, pp. 1-5.
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© 1965-2012 IEEE. In this paper, a new 3-D flux transverse flux flux switching permanent magnet machine (3-DFTFFSPMM) is proposed. The cost of this machine is very low since both the soft magnetic composite (SMC) cores and ferrite magnets are very cheap, and the performance of this machine is good due to the special designed topology. For the qualitative analysis and initial design, the simplified power equation is developed to find the optimal design, and the 3-D finite-element method is applied for the quantitative analysis. Considering it is very difficult to obtain a special ferrite magnet in the current market, the 3-DFTFFSPMM for prototyping in the workshop is improved with a new design. For the prototyping, the SMC cores are made by using the manual die compacting technology. Last, the efficiency map of these two machines is obtained to judge the operational performance.
Liu, C, Lei, G, Wang, T, Guo, Y, Wang, Y & Zhu, J 2017, 'Comparative Study of Small Electrical Machines With Soft Magnetic Composite Cores', IEEE Transactions on Industrial Electronics, vol. 64, no. 2, pp. 1049-1060.
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© 1982-2012 IEEE. In this paper, various kinds of electrical machines with soft magnetic composite (SMC) cores are compared, based on the qualitative and quantitative comparison methods. In the first part, the performances of five typical electrical machines with SMC cores are qualitatively compared. Simplified power equations for transverse flux, axial flux, and radial flux electrical machines are deduced to show the main difference among them and key design points of each machine. In the second part, the outer rotor claw pole machine (CPM) and outer rotor transverse flux machine (TFM) are comprehensively compared in a quantitative way, based on the three-dimensional finite-element method. It shows that the power capability of the outer rotor CPM is much higher than that of the TFM. On the other hand, the outer rotor CPM has higher cogging torque and no-load losses than the TFM. Furthermore, the four outer rotor radial flux machines are optimized and compared with the outer rotor CPM. The calculated results of the outer rotor TFM are compared with the experiment results, showing that the analysis results match well with the experiment ones. Several useful and interesting conclusions have been obtained for the electrical machines with SMC cores.
Liu, C, Lu, J, Wang, Y, Lei, G, Zhu, J & Guo, Y 2017, 'Techniques for Reduction of the Cogging Torque in Claw Pole Machines with SMC Cores', Energies, vol. 10, no. 10, pp. 1541-1541.
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© 2017 MDPI AG. All Rights Reserved. As one of the main parasitic parameters in permanent magnet (PM) synchronous machines (PMSMs), cogging torque is the main component of the torque ripple, which has always been the handicap in the high-performance, low-speed drive systems. Over the last two decades, various methods have been proposed to decrease the cogging torque in both radial-flux and axial-flux PMSMs. Among these methods, stator slot skewing, stator tooth notching, PM skewing, PM shifting, and pole pairing are extensively investigated. However, little work has been done on reducing the cogging torque of the claw pole machine (CPM), whose cogging torque cannot be ignored. In this paper, the general methods that have been used to reduce the cogging torque in radial-flux and axial-flux PMSMs are developed and verified in a CPM with a soft magnetic composite (SMC) core. The 3-D finite element method (FEM) is used to calculate the cogging torque and PM flux linkage per turn. By comparing different cogging torque reduction technologies, it can be found that the magnet step skewing and unequal claw pole width are very suitable for CPM.
Liu, C, Wang, Y, Lei, G, Guo, Y & Zhu, J 2017, 'Design and analysis of a 3D-flux flux-switching permanent magnet machine with SMC cores and ferrite magnets', AIP Advances, vol. 7, no. 5, pp. 056632-056632.
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Since permanent magnets (PM) are stacked between the adjacent stator teeth and there are no windings or PMs on the rotor, flux-switching permanent magnet machine (FSPMM) owns the merits of good flux concentrating and robust rotor structure. Compared with the traditional PM machines, FSPMM can provide higher torque density and better thermal dissipation ability. Combined with the soft magnetic composite (SMC) material and ferrite magnets, this paper proposes a new 3D-flux FSPMM (3DFFSPMM). The topology and operation principle are introduced. It can be found that the designed new 3DFFSPMM has many merits over than the traditional FSPMM for it can utilize the advantages of SMC material. Moreover, the PM flux of this new motor can be regulated by using the mechanical method. 3D finite element method (FEM) is used to calculate the magnetic field and parameters of the motor, such as flux density, inductance, PM flux linkage and efficiency map. The demagnetization analysis of the ferrite magnet is also addressed to ensure the safety operation of the proposed motor.
Liu, C, Wang, Y, Lei, G, Guo, Y & Zhu, J 2017, 'Performance analysis of a new radial-axial flux machine with SMC cores and ferrite magnets', AIP Advances, vol. 7, no. 5, pp. 056603-056603.
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Soft magnetic composite (SMC) is a popular material in designing of new 3D flux electrical machines nowadays for it has the merits of isotropic magnetic characteristic, low eddy current loss and high design flexibility over the electric steel. The axial flux machine (AFM) with the extended stator tooth tip both in the radial and circumferential direction is a good example, which has been investigated in the last years. Based on the 3D flux AFM and radial flux machine, this paper proposes a new radial-axial flux machine (RAFM) with SMC cores and ferrite magnets, which has very high torque density though the low cost low magnetic energy ferrite magnet is utilized. Moreover, the cost of RAFM is quite low since the manufacturing cost can be reduced by using the SMC cores and the material cost will be decreased due to the adoption of the ferrite magnets. The 3D finite element method (FEM) is used to calculate the magnetic flux density distribution and electromagnetic parameters. For the core loss calculation, the rotational core loss computation method is used based on the experiment results from previous 3D magnetic tester.
Liu, W, Chen, X, Yang, J & Wu, Q 2017, 'Robust Color Guided Depth Map Restoration', IEEE Transactions on Image Processing, vol. 26, no. 1, pp. 315-327.
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© 1992-2012 IEEE. One of the most challenging issues in color guided depth map restoration is the inconsistency between color edges in guidance color images and depth discontinuities on depth maps. This makes the restored depth map suffer from texture copy artifacts and blurring depth discontinuities. To handle this problem, most state-of-the-art methods design complex guidance weight based on guidance color images and heuristically make use of the bicubic interpolation of the input depth map. In this paper, we show that using bicubic interpolated depth map can blur depth discontinuities when the upsampling factor is large and the input depth map contains large holes and heavy noise. In contrast, we propose a robust optimization framework for color guided depth map restoration. By adopting a robust penalty function to model the smoothness term of our model, we show that the proposed method is robust against the inconsistency between color edges and depth discontinuities even when we use simple guidance weight. To the best of our knowledge, we are the first to solve this problem with a principled mathematical formulation rather than previous heuristic weighting schemes. The proposed robust method performs well in suppressing texture copy artifacts. Moreover, it can better preserve sharp depth discontinuities than previous heuristic weighting schemes. Through comprehensive experiments on both simulated data and real data, we show promising performance of the proposed method.
Liu, W, Chen, X, Yang, J & Wu, Q 2017, 'Variable Bandwidth Weighting for Texture Copy Artifact Suppression in Guided Depth Upsampling', IEEE Transactions on Circuits and Systems for Video Technology, vol. 27, no. 10, pp. 2072-2085.
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© 2017 IEEE. In this paper, we mathematically analyze one of the most challenging issues in color image-guided depth upsampling: the texture copy artifacts. The optimal guidance weights denoted by balanced weights are proposed to best suppress texture copy artifacts. To both suppress texture copy artifacts and preserve depth discontinuities, a new general weighting scheme called variable bandwidth weighting is proposed. The variable bandwidth weighting scheme is able to adjust guidance weights according to the local depth smoothness. A new concept called relative smoothness is proposed for measuring the local depth smoothness. Given this quantitative smoothness measurement, the proposed weighting scheme can adaptively adjust the bandwidth for calculating the guidance weights in the existing methods. As we use the computationally efficient balanced weights instead of the guidance weights of a large bandwidth, the proposed method can speed up the upsampling process for about 2× ∼ 5× when compared with the original upsampling methods. Experimental results show the effectiveness and efficiency of the proposed method in suppressing texture copy artifacts, preserving the depth discontinuities and reducing the computational cost at the same time.
Liu, W, Luo, X, Zhang, J, Xue, R & Xu, RYD 2017, 'Semantic summary automatic generation in news event', Concurrency and Computation: Practice and Experience, vol. 29, no. 24, pp. e4287-e4287.
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SummaryHow to generate summary with more novel and rich semantics is a challenging issue in the area of multi‐document automatic summary. In this paper, a core semantics extraction model (CSEM) is proposed to improve the novel and rich semantics of multi‐document summary. Firstly, for improving the rich semantics, semantic units, which are a group of association relations of keywords, are used to express texts' semantics. Secondly, for improving the novel semantics, an attenuation function is introduced to adjust the importance of semantic units according to the appearing times that semantic units in the candidate of summary sentences. Thirdly, in order to maximize the novel and rich semantics of summary, the generating process of summary is converted into the optimization process on how to find a set of sentences with a higher importance. Finally, CSEM extracts the least number of sentences to cover the most core semantics in corpus as summary. Experimental results on the benchmark DUC 2004 show that our model outperforms the state‐of‐art approaches (eg, OCCAMS_V, JS‐Gen‐2) under official metric. Especially, the recall of our model in ROUGE‐1 is 40.684%, which is better than other approaches (eg, OCCAMS_V 38.497% and JS‐Gen‐2 36.739%).
Liu, X, He, Y, Zheng, X, Zhang, J & Zeng, G 2017, 'A new state-of-charge estimation method for electric vehicle lithium-ion batteries based on multiple input parameter fitting model', International Journal of Energy Research, vol. 41, no. 9, pp. 1265-1276.
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Copyright © 2017 John Wiley & Sons, Ltd. The estimation of state-of-charge (SOC) is crucial to determine the remaining capacity of the Lithium-Ion battery, and thus plays an important role in many electric vehicle control and energy storage management problems. The accuracy of the estimated SOC depends mostly on the accuracy of the battery model, which is mainly affected by factors like temperature, State of Health (SOH), and chemical reactions. Also many characteristic parameters of the battery cell, such as the output voltage, the internal resistance and so on, have close relations with SOC. Battery models are often identified by a large amount of experiments under different SOCs and temperatures. To resolve this difficulty and also improve modeling accuracy, a multiple input parameter fitting model of the Lithium-Ion battery and the factors that would affect the accuracy of the battery model are derived from the Nernst equation in this paper. Statistics theory is applied to obtain a more accurate battery model while using less measurement data. The relevant parameters can be calculated by data fitting through measurement on factors like continuously changing temperatures. From the obtained battery model, Extended Kalman Filter algorithm is applied to estimate the SOC. Finally, simulation and experimental results are given to illustrate the advantage of the proposed SOC estimation method. It is found that the proposed SOC estimation method always satisfies the precision requirement in the relevant Standards under different environmental temperatures. Particularly, the SOC estimation accuracy can be improved by 14% under low temperatures below 0 °C compared with existing methods. Copyright © 2017 John Wiley & Sons, Ltd.
Liu, X, Lv, J, Gao, C, Chen, Z, Guo, Y, Gao, Z & Tai, B 2017, 'A Novel Diode-Clamped Modular Multilevel Converter With Simplified Capacitor Voltage-Balancing Control', IEEE Transactions on Industrial Electronics, vol. 64, no. 11, pp. 8843-8854.
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© 1982-2012 IEEE. Multilevel converters have become very attractive for high-voltage-level power conversion in renewable power generation applications. The converter topology is an important issue in the studies of multilevel converter. Many multilevel topologies have been developed, but few of them are qualified with capacitor voltage self-balancing capability. This paper proposes a novel diode-clamped modular multilevel converter with simplified capacitor voltage-balancing control. In this topology, low-power rating diodes are used to clamp the capacitor voltages of the converter. Only the top submodule in each arm of the converter requires capacitor voltage control. Consequently, very few voltage sensors are needed for voltage control and the control computation burden is reduced greatly when the quantity of the submodules is high. A simple voltage-balancing control method with carrier phase-shifted modulation strategy is developed for this topology. Experiments based on a laboratory prototype were carried out and the results validated the capacitor-balancing performance of the proposed topology.
Liu, X, Sun, Y, He, Y, Zheng, X, Zeng, G & Zhang, J 2017, 'Battery Equalization by Fly-Back Transformers with Inductance, Capacitance and Diode Absorbing Circuits', Energies, vol. 10, no. 10, pp. 1482-1482.
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© 2017 by the authors. Battery equalization can increase batteries' life cycle, utilization, and reliability. Compared with battery equalization topologies based on resistance or energy storage components, the topologies based on transformers have the advantages of high balancing current and efficiency. However, the existence of switching losses will reduce the reliability and service life span of the equalization circuit. Aiming at resolving this problem, a new battery equalization topology by fly-back transformer with an absorbing circuit is proposed in this paper. Compared with other transformer-based topologies, it can decrease switching losses because the voltage/current spike is solved by the absorbing circuit which is composed of inductance, capacitance and diode (LCD), and it can also maintain a high balancing current of about 1.8 A and high efficiency of about 89%, while the balancing current and efficiency of other topologies were usually 1.725 A/1.5 A and 80%/80.4%. The working principle of the balancing topology and the process of soft switching are analyzed and calculated in the frequency domain. Due to the addition of the LCD absorbing circuit, soft switching can be realized to reduce the switching losses while the high equalization speed and efficiency are still maintained. The corresponding control strategy of the balancing topology is also proposed and the timely balancing is achieved. The theoretical analysis is verified by simulation and experimental results.
Lu, Z, He, L, Zhang, D, Zhao, B, Zhang, J & Zhao, H 2017, 'A Security Level Classification Method for Power Systems under N-1 Contingency', Energies, vol. 10, no. 12, pp. 2055-2055.
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Security assessment is crucial for the reliable and secure operation of power systems. This paper proposes a security level classification (SLC) method to analyze the security level of power systems both qualitatively and quantitatively. In this SLC method, security levels are graded according to a comprehensive safety index (CSI), which is defined by integrating the system margin index (SMI) and load entropy. The SMI depends on the operating load and the total supply capacity (TSC) under N-1 contingency, and the load entropy reflects the heterogeneity of load distribution calculated from entropy theory. In order to calculate the TSC under N-1 contingency considering both of the computational accuracy and speed, the TSC is converted into an extended conic quadratic programming (ECQP) model. In addition, the load boundary vector (LBV) model is established to obtain the capacity limit of each load bus, and thus detect potential risks of power systems. Finally, two modified practical power systems and the IEEE 118-bus test system are studied to validate the feasibility of the proposed SLC method.
Lu, Z, Qi, J, Zhang, J, He, L & Zhao, H 2017, 'Modelling dynamic demand response for plug‐in hybrid electric vehicles based on real‐time charging pricing', IET Generation, Transmission & Distribution, vol. 11, no. 1, pp. 228-235.
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Based on the benefits of real-time pricing both to individual users and the society as a whole, this study introduces a real-time charging price (RTCP) mechanism supported by an intelligent charging management module into plug-in hybrid electric vehicles (PHEVs) charging environment. The optimal RTCP is executed by a distributed algorithm using a utility model to maximise the whole charging system welfare. The willingness-to-charge parameter is derived to reflect the charging preferences of PHEV users and their different responses to the RTCP. Several scenarios are established to discuss the effect of both the RTCP and willingness-to-charge on charging load. The simulation results show that reasonable charging will be realised based on the optimal RTCP mechanism.
Luo, W, Li, J, Yang, J, Xu, W & Zhang, J 2017, 'Convolutional Sparse Autoencoders for Image Classification', IEEE Transactions on Neural Networks and Learning Systems, pp. 1-6.
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Luong, NC, Hoang, DT, Wang, P, Niyato, D & Han, Z 2017, 'Applications of Economic and Pricing Models for Wireless Network Security: A Survey', IEEE Communications Surveys & Tutorials, vol. 19, no. 4, pp. 2735-2767.
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© 1998-2012 IEEE. This paper provides a comprehensive literature review on applications of economic and pricing theory to security issues in wireless networks. Unlike wireline networks, the broadcast nature and the highly dynamic change of network environments pose a number of nontrivial challenges to security design in wireless networks. While the security issues have not been completely solved by traditional or system-based solutions, economic and pricing models recently were employed as one efficient solution to discourage attackers and prevent attacks to be performed. In this paper, we review economic and pricing approaches proposed to address major security issues in wireless networks including eavesdropping attack, denial-of-service (DoS) attack such as jamming and distributed DoS, and illegitimate behaviors of malicious users. Additionally, we discuss integrating economic and pricing models with cryptography methods to reduce information privacy leakage as well as to guarantee the confidentiality and integrity of information in wireless networks. Finally, we highlight important challenges, open issues and future research directions of applying economic and pricing models to wireless security issues.
Lyu, X, Ni, W, Tian, H, Liu, RP, Wang, X, Giannakis, GB & Paulraj, A 2017, 'Optimal Schedule of Mobile Edge Computing for Internet of Things Using Partial Information', IEEE Journal on Selected Areas in Communications, vol. 35, no. 11, pp. 2606-2615.
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© 1983-2012 IEEE. Mobile edge computing is of particular interest to Internet of Things (IoT), where inexpensive simple devices can get complex tasks offloaded to and processed at powerful infrastructure. Scheduling is challenging due to stochastic task arrivals and wireless channels, congested air interface, and more prominently, prohibitive feedbacks from thousands of devices. In this paper, we generate asymptotically optimal schedules tolerant to out-of-date network knowledge, thereby relieving stringent requirements on feedbacks. A perturbed Lyapunov function is designed to stochastically maximize a network utility balancing throughput and fairness. A knapsack problem is solved per slot for the optimal schedule, provided up-to-date knowledge on the data and energy backlogs of all devices. The knapsack problem is relaxed to accommodate out-of-date network states. Encapsulating the optimal schedule under up-to-date network knowledge, the solution under partial out-of-date knowledge preserves asymptotic optimality, and allows devices to self-nominate for feedback. Corroborated by simulations, our approach is able to dramatically reduce feedbacks at no cost of optimality. The number of devices that need to feed back is reduced to less than 60 out of a total of 5000 IoT devices.
Lyu, X, Tian, H, Ni, W, Liu, RP & Zhang, P 2017, 'Adaptive Centralized Clustering Framework for Software-Defined Ultra-Dense Wireless Networks', IEEE Transactions on Vehicular Technology, vol. 66, no. 9, pp. 8553-8557.
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© 2017 IEEE. This paper develops a new centralized clustering framework to mitigate strong intercell interference in a software-defined ultra-dense network, where the number of clusters can be adapting to network conditions. A directed interference graph is designed to capture the dominant interference resulting from user mobility. An asymptotically optimal Max-K-Cut method is proposed to partition the graph, achieving a ( $1-1/K$) approximation of the optimum in a polynomial time-complexity, where $K$ is the number of clusters. As a result, $K$ can be adaptively adjusted to leverage among the optimality loss, throughput, and complexity. Numerical results show that our adaptive centralized framework performs significantly better than other centralized or semidistributed clustering schemes in terms of throughput.
Mahamedi, B & Zhu, JG 2017, 'Double‐ended technique for distinguishing series faults from shunt faults on transmission lines using the sequential components of impedance', IET Generation, Transmission & Distribution, vol. 11, no. 6, pp. 1381-1388.
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© 2017 The Institution of Engineering and Technology. This study describes a new double-ended technique for distinguishing series faults from shunt faults. The proposed method is based on the sequential components of impedance. Using the local and remote positive-sequence voltage and the local positive-sequence current, a new value is introduced and utilised to distinguish series faults, mostly known as broken conductors, from shunt faults. As the proposed method utilises a double-ended technique, it will act when the necessary information of the remote end of the line is received. By detecting the broken conductor condition within a few power cycles, this method can trip the circuit breakers at both line ends before any conductor contacts the earth, and thus can avoid safety problems and damages to the electrical equipment. Moreover, it can also classify which type of broken conductor (one-phase or two-phase) condition has occurred. The excellent performance of the proposed method is demonstrated by extensive simulation studies with MATLAB/Simulink.
Mahmud, MA, Hossain, MJ, Pota, HR & Oo, AMT 2017, 'Robust Partial Feedback Linearizing Excitation Controller Design for Multimachine Power Systems', IEEE Transactions on Power Systems, vol. 32, no. 1, pp. 3-16.
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This paper presents a new robust nonlinear excitation controller design for synchronous generators in multimachine power systems to enhance the transient stability. The mismatches between the original power system model and formulated mathematical model are considered as uncertainties, which are modeled through the satisfaction of matching conditions. The exogenous noises appearing from measurements are incorporated with the power system model including the two-axis model of synchronous generators. The partial feedback linearization technique is used to design the controller which transforms the original nonlinear multimachine power system model into several reduced-order linear and autonomous subsystems. The desired control law is obtained for each subsystem and implemented in a decentralized manner provided that the dynamics of the autonomous subsystems have no effects on the overall stability of the system. The analysis related to the dynamics of noisy autonomous subsystems is also included and the proposed controller has the excellent capability to decouple these noises. Finally, the performance of the proposed control scheme is evaluated on an IEEE 39-bus benchmark power system following different types of large disturbances. The performance of the proposed controller is compared to that of a partial feedback linearizing controller, which is designed without robustness properties, to verify the effectiveness of the proposed control scheme.
Mao, X, Wang, Y, Liu, X & Guo, Y 2017, 'An adaptive weighted least square support vector regression for hysteresis in piezoelectric actuators', Sensors and Actuators A: Physical, vol. 263, pp. 423-429.
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© 2017 Elsevier B.V. To overcome the low positioning accuracy of piezoelectric actuators (PZAs) caused by the hysteresis nonlinearity, this paper proposes an adaptive weighted least squares support vector regression (AWLSSVR) to model the rate-dependent hysteresis of PZA. Firstly, the AWLSSVR hyperparameters are optimized by using particle swarm optimization. Then an adaptive weighting strategy is proposed to eliminate the effects of noises in the training dataset and reduce the sample size at the same time. Finally, the proposed approach is applied to predict the hysteresis of PZA. The results show that the proposed method is more accurate than other versions of least squares support vector regression for training samples with noises, and meanwhile reduces the sample size and speeds up calculation.
Matekovits, L, Huang, J, Peter, I & Esselle, KP 2017, 'Mutual Coupling Reduction Between Implanted Microstrip Antennas on a Cylindrical Bio-Metallic Ground Plane', IEEE Access, vol. 5, pp. 8804-8811.
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McGloin, D 2017, 'Droplet lasers: a review of current progress', Reports on Progress in Physics, vol. 80, no. 5, pp. 054402-054402.
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© 2017 IOP Publishing Ltd. It is perhaps surprising that something as fragile as a microscopic droplet could possibly form a laser. In this article we will review some of the underpinning physics as to how this might be possible, and then examine the state of the art in the field. The technology to create and manipulate droplets will be examined, as will the different classes of droplet lasers. We discuss the rapidly developing fields of droplet biolasers, liquid crystal laser droplets and explore how droplet lasers could give rise to new bio and chemical sensing and analysis. The challenges that droplet lasers face in becoming robust devices, either as sensors or as photonic components in the lab on chip devices, is assessed.
Mishra, N, Boeckl, JJ, Tadich, A, Jones, RT, Pigram, PJ, Edmonds, M, Fuhrer, MS, Nichols, BM & Iacopi, F 2017, 'Solid source growth of graphene with Ni–Cu catalysts: towards high qualityin situgraphene on silicon', Journal of Physics D: Applied Physics, vol. 50, no. 9, pp. 095302-095302.
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We obtain a monolayer graphene on epitaxial silicon carbide on silicon substrates via solid source growth mediated by a thin Ni-Cu alloy. Raman spectroscopy consistently shows an I D /I G band ratio as low as ∼0.2, indicating that the graphene obtained through this method is to-date the best quality monolayer grown on epitaxial silicon carbide films on silicon. We describe the key steps behind the graphene synthesis on the basis of extensive physical, chemical and morphological analyses. We conclude that (1) the oxidation, amorphisation and silicidation of the silicon carbide surface mediated by the Ni, (2) the liquid-phase epitaxial growth of graphene as well as (3) the self-limiting graphitization provided the molten Cu catalyst, are key characteristics of this novel synthesis method.
Mokgonyana, L, Zhang, J, Li, H & Hu, Y 2017, 'Optimal location and capacity planning for distributed generation with independent power production and self-generation', Applied Energy, vol. 188, pp. 140-150.
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� 2016 Elsevier Ltd This paper proposes a planning model for power distribution companies (DISCOs) to maximize profit. The model determines optimal network location and capacity for renewable energy source, which are categorized as independent power production (IPP) and self-generation (SG). IPP refers to generators owned by third-party investors and linked to a quota obligation mechanism. SG encompasses smaller generators, supported by feed-in tariffs, that produce energy for local consumption, exporting any surplus generation to the distribution network. The obtained optimal planning model is able to evaluate network capacity to maximize profit when the DISCO is obliged to provide network access to SG and IPP. Distinct parts of the objective function, owing to the definition of SG, are revenue erosion, recovery as well as the cost of excess energy. Together with the quota mechanism for IPP, the combination of all profit components creates a connection trade-off between IPP and SG for networks with limited capacity. The effectiveness of the model is tested on 33- and 69-bus test distribution systems and compared to standard models that maximize generation capacity with predefined capacity diffusion. Simulation results demonstrate the model outperforms the standard models in satisfying the following binding constraints: minimum IPP capacity and SG net energy. It is further revealed that integrating SG and IPP with the proposed model increases profit by up to 23.7%, adding an improvement of 8% over a feasible standard model.
Morshed, KM, Karmokar, DK & Esselle, KP 2017, 'Low profile single-layer U-slot loaded shorted-patch antenna for wireless communications', Microwave and Optical Technology Letters, vol. 59, no. 9, pp. 2224-2226.
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© 2017 Wiley Periodicals, Inc. A U-slot loaded single-layer compact shorted-patch antenna is presented for wireless communications in the 5.8 GHz band. The size of the prototyped antenna is only 30 mm × 30 mm, which is very small compared to single-layer antennas for the same frequency band. The measured −10 dB reflection coefficient bandwidth of the antenna is 140 MHz (5.67–5.81 GHz). The peak measured boresight gain and directivity of the antenna are 7.4 and 8 dBi, respectively, and their variation within the band is less than 1 dB. The measured 3-dB beamwidths of the antenna at 5.8 GHz are 79° and 69° in the E-plane and H-plane, respectively. An easy way to shift the antenna resonance frequency is also investigated.
Muhammad, KS, Baharom, R, Seroji, MN & Lu, DDC 2017, 'Totem-pole bridgeless boost PFC rectifier using series-parallel resonant network', Journal of Telecommunication, Electronic and Computer Engineering, vol. 9, no. 2-7, pp. 83-88.
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A new series-parallel resonant bridgeless boost (SPBBR) power factor correction (PFC) rectifier is proposed in this paper. It is based on a totem-pole bridgeless boost (TPBLB) configuration which allows bi-directional current to flow during resonance to provide soft-switching for all semiconductor devices. Therefore, no additional active switch is needed. The resonant is produced by a resonant network which is placed before the output capacitor. A detailed analysis of the converter operation and control is presented. Design considerations and parameter values determination are also given. Simulation results is used to verify the theoretical analysis of the SPBBR.
Nam, TM, Thanh, NH, Hieu, HT, Manh, NT, Huynh, NV & Tuan, HD 2017, 'Joint network embedding and server consolidation for energy–efficient dynamic data center virtualization', Computer Networks, vol. 125, pp. 76-89.
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© 2017 Elsevier B.V. Cloud computing has emerged in recent years as a promising paradigm that facilitates such new service models as Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). As the number of cloud service provider increases, there exists a demand to dynamically provision virtual data centers (VDC) on top of the infrastructure provider's physical data centers. This research addresses problems related to energy and resource efficiently embedding virtual data centers inside physical data centers under dynamic resource allocation conditions, in which VDCs continuously join and leave the system. Dynamic VDC embedding is challenging as it is an NP-hard problem that should meet multiple objectives. In this article, we propose heuristic joint VDC embedding – server consolidation approaches as one solution for that problem. Evaluation results show that the joint approach outperforms existing ones in terms of resource and energy efficiency and can keep system complexity acceptable.
Nasir, AA, Tuan, HD, Duong, TQ & Poor, HV 2017, 'Secrecy Rate Beamforming for Multicell Networks With Information and Energy Harvesting', IEEE Transactions on Signal Processing, vol. 65, no. 3, pp. 677-689.
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© 2016 IEEE. Considering a multicell network for the secure wireless information and power transfer, this paper studies the joint design of transmit beamformers at the base stations (BSs) and receive signal splitting ratios at the end users' equipment (UE). The primary concern in this work is the network internal security, where there may be a single multiantenna eavesdropper or there is a risk that any near user may accidentally eavesdrop on the received signal of any far user. The objective is to maximize the minimum secrecy user rate under BS transmit power and UE minimum harvested energy constraints. New path-following algorithms are proposed for computational solutions of these difficult nonconvex optimization problems. Each iteration involves one simple convex quadratic program. Numerical results confirm that the proposed algorithms converge quickly after few iterations having a low computational complexity.
Nasir, AA, Tuan, HD, Duong, TQ & Poor, HV 2017, 'Secure and Energy-Efficient Beamforming for Simultaneous Information and Energy Transfer', IEEE Transactions on Wireless Communications, vol. 16, no. 11, pp. 7523-7537.
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© 2017 IEEE. Some next-generation wireless networks will likely involve the energy-efficient transfer of information and energy over the same wireless channel. Moreover, densification of such networks will make the physical layer more vulnerable to cyber attacks by potential multi-antenna eavesdroppers. To address these issues, this paper considers transmit time-switching (TS) mode, in which energy and information signals are transmitted separately in time by the base station (BS). This protocol is not only easy to implement but also delivers the opportunity for multi-purpose beamforming, in which energy beamformers can be used to jam eavesdroppers during wireless power transfer. In the presence of imperfect channel estimation and multi-antenna eavesdroppers, the energy and information beamformers and the transmit TS ratio are jointly optimized to maximize the worst-case user secrecy rate subject to energy constrained users' harvested energy thresholds and a BS transmit power budget. New robust path-following algorithms, which involve one simple convex quadratic program at each iteration are proposed for computational solutions of this difficult optimization problem and also the problem of secure energy efficiency maximization. The latter adds further complexity due to additional optimization variables appearing in the denominator of the secrecy rate function. Numerical results confirm that the performance of the proposed computational solutions is robust against channel uncertainties.
Nasir, AA, Tuan, HD, Ngo, DT, Duong, TQ & Poor, HV 2017, 'Beamforming Design for Wireless Information and Power Transfer Systems: Receive Power-Splitting Versus Transmit Time-Switching', IEEE Transactions on Communications, vol. 65, no. 2, pp. 876-889.
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© 1972-2012 IEEE. Information and energy can be transferred over the same radio-frequency channel. In the power-splitting (PS) mode, they are simultaneously transmitted using the same signal by the base station (BS) and later separated at the user (UE)'s receiver by a power splitter. In the time-switching (TS) mode, they are either transmitted separately in time by the BS or received separately in time by the UE. In this paper, the BS transmit beamformers are jointly designed with either the receive PS ratios or the transmit TS ratios in a multicell network that implements wireless information and power transfer (WIPT). Imposing UE-harvested energy constraints, the design objectives include: 1) maximizing the minimum UE rate under the BS transmit power constraint, and 2) minimizing the maximum BS transmit power under the UE data rate constraint. New iterative algorithms of low computational complexity are proposed to efficiently solve the formulated difficult nonconvex optimization problems, where each iteration either solves one simple convex quadratic program or one simple second-order-cone-program. Simulation results show that these algorithms converge quickly after only a few iterations. Notably, the transmit TS-based WIPT system is not only more easily implemented but outperforms the receive PS-based WIPT system as it better exploits the beamforming design at the transmitter side.
Nghia, NT, Tuan, HD, Duong, TQ & Poor, HV 2017, 'MIMO Beamforming for Secure and Energy-Efficient Wireless Communication', IEEE Signal Processing Letters, vol. 24, no. 2, pp. 236-239.
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Considering a multiple-user multiple-input multiple-output (MIMO) channelwith an eavesdropper, this letter develops a beamformer design to optimize theenergy efficiency in terms of secrecy bits per Joule under secrecyquality-of-service constraints. This is a very difficult design problem with noavailable exact solution techniques. A path-following procedure, whichiteratively improves its feasible points by using a simple quadratic program ofmoderate dimension, is proposed. Under any fixed computational tolerance theprocedure terminates after finitely many iterations, yielding at least alocally optimal solution. Simulation results show the superior performance ofthe obtained algorithm over other existing methods.
Ngo, QH, Nguyen, NP, Nguyen, CN, Tran, TH & Ha, QP 2017, 'Fuzzy sliding mode control of an offshore container crane', Ocean Engineering, vol. 140, pp. 125-134.
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© 2017 A fuzzy sliding mode control strategy for offshore container cranes is investigated in this study. The offshore operations of loading and unloading containers are performed between a mega container ship, called the mother ship, and a smaller ship, called the mobile harbor (MH), which is equipped with a container crane. The MH is used to transfer the containers, in the open sea, and deliver them to a conventional stevedoring port, thereby minimizing the port congestion and also eliminating the need of expanding outwards. The control objective during the loading and unloading process is to keep the payload in a desired tolerance in harsh conditions of the MH motion. The proposed control strategy combines a fuzzy sliding mode control law and a prediction algorithm based on Kalman filtering for the MH roll angle. Here, the sliding surface is designed to incorporate the desired trolley trajectory while suppressing the sway motion of the payload. To improve the control performance, the discontinuous gain of the sliding control is adjusted with fuzzy logic tuning schemes with respect to the sliding function and its rate of change. Chattering is further reduced by a saturation function. Simulation and experimental results are provided to verify the effectiveness of the proposed control system for offshore container cranes.
Ngoc, PHA & Ha, Q 2017, 'On exponential stability of linear non-autonomous functional differential equations of neutral type', International Journal of Control, vol. 90, no. 3, pp. 438-446.
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© 2016 Informa UK Limited, trading as Taylor & Francis Group. General linear non-autonomous functional differential equations of neutral type are considered. A novel approach to exponential stability of neutral functional differential equations is presented. Consequently, explicit criteria are derived for exponential stability of linear non-autonomous functional differential equations of neutral type. A brief discussion to the obtained results and illustrative examples are given.
Nguyen, M, Kim, S, Tran, TT, Xu, Z-Q, Kianinia, M, Toth, M & Aharonovich, I 2017, 'Nanoassembly of quantum emitters in hexagonal boron nitride and gold nanospheres', Nanoscale, vol. 10, no. 5, pp. 2267-2274.
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Assembly of quantum nanophotonic systems with plasmonic resonators areimportant for fundamental studies of single photon sources as well as foron-chip information processing. In this work, we demonstrate controllablenanoassembly of gold nanospheres with ultra-bright quantum emitters in 2Dlayered hexagonal boron nitride (hBN). We utilize an atomic force microscope(AFM) tip to precisely position gold nanospheres to close proximity of thequantum emitters and observe the resulting emission enhancement andfluorescence lifetime reduction. A fluorescence enhancement of over 300% isachieved experimentally for quantum emitters in hBN, with a radiative quantumefficiency of up to 40% and a saturated count rate in excess of 5 millioncounts/s. Our results are promising for future employment of quantum emittersin hBN for integrated nanophotonic devices and plasmonic based nanosensors.
Nguyen, N-P, Ngo, HQ, Duong, TQ, Tuan, HD & da Costa, DB 2017, 'Full-Duplex Cyber-Weapon With Massive Arrays', IEEE Transactions on Communications, vol. 65, no. 12, pp. 5544-5558.
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© 2017 IEEE. In order to enhance secrecy performance of protecting scenarios, understanding the illegitimate side is crucial. In this paper, from the perspective of the illegitimate side, the security attack from a full-duplex cyber-weapon equipped with massive antenna arrays is considered. To evaluate the behavior of the proposed cyber-weapon, we develop a closed-form, a tight approximation, and asymptotic expressions of the achievable ergodic secrecy rate with taking into consideration imperfect channel estimation at the cyber-weapon. The results show that even under some disadvantage conditions, i.e., imperfect channel estimation and self-interference, the full-duplex massive array cyber-weapon can disable traditional physical layer protecting schemes, i.e., increasing the transmit power and the number of antennas at the legitimate transmitter. In addition, when a transmit power optimization scheme for maximizing the difference between the eavesdropping rate and the legitimate rate is applied at the full-duplex cyber-weapon, the malicious attack is even more dangerous. The results also reveal that when the legitimate side faces an advance adversary, it is essential to prevent important information in the training phases exposing to the illegitimate side.
Nguyen, V-D, Duong, TQ, Tuan, HD, Shin, O-S & Poor, HV 2017, 'Spectral and Energy Efficiencies in Full-Duplex Wireless Information and Power Transfer', IEEE Transactions on Communications, vol. 65, no. 5, pp. 2220-2233.
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© 2017 IEEE. A communication system is considered consisting of a full-duplex multiple-antenna base station (BS) and multiple single-antenna downlink users (DLUs) and single-antenna uplink users (ULUs), where the latter need to harvest energy for transmitting information to the BS. The communication is thus divided into two phases. In the first phase, the BS uses all available antennas for conveying information to DLUs and wireless energy to ULUs via information and energy beamforming, respectively. In the second phase, ULUs send their independent information to the BS using their harvested energy while the BS transmits the information to the DLUs. In both the phases, the communication is operated at the same time and over the same frequency band. The aim is to maximize the sum rate and energy efficiency under ULU achievable information throughput constraints by jointly optimizing beamforming and time allocation. The utility functions of interest are nonconcave and the involved constraints are nonconvex, so these problems are computationally troublesome. To address them, path-following algorithms are proposed to arrive at least at local optima. The proposed algorithms iteratively improve the objectives with convergence guaranteed. Simulation results demonstrate that they achieve rapid convergence and outperform conventional solutions.
Nguyen, V-D, Tuan, HD, Duong, TQ, Poor, HV & Shin, AO-S 2017, 'Precoder Design for Signal Superposition in MIMO-NOMA Multicell Networks', IEEE Journal on Selected Areas in Communications, vol. 35, no. 12, pp. 2681-2695.
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The throughput of users with poor channel conditions, such as those at a celledge, is a bottleneck in wireless systems. A major part of the power budgetmust be allocated to serve these users in guaranteeing their quality-of-service(QoS) requirement, hampering QoS for other users and thus compromising thesystem reliability. In nonorthogonal multiple access (NOMA), the messageintended for a user with a poor channel condition is decoded by itself and byanother user with a better channel condition. The message intended for thelatter is then successively decoded by itself after canceling the interferenceof the former. The overall information throughput is thus improved by thisparticular successive decoding and interference cancellation. This paper aimsto design linear precoders/beamformers for signal superposition at the basestations of NOMA multi-input multi-output multi-cellular systems to maximizethe overall sum throughput subject to the users' QoS requirements, which areimposed independently on the users' channel condition. This design problem isformulated as the maximization of a highly nonlinear and nonsmooth functionsubject to nonconvex constraints, which is very computationally challenging.Path-following algorithms for its solution, which invoke only a simple convexproblem of moderate dimension at each iteration are developed. Generating asequence of improved points, these algorithms converge at least to a localoptimum. Extensive numerical simulations are then provided to demonstrate theirmerit.
Nguyen, V-D, Tuan, HD, Duong, TQ, Shin, O-S & Poor, HV 2017, 'Joint Fractional Time Allocation and Beamforming for Downlink Multiuser MISO Systems', IEEE Communications Letters, vol. 21, no. 12, pp. 2650-2653.
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It is well-known that the traditional transmit beamforming at a base station(BS) to manage interference in serving multiple users is effective only whenthe number of users is less than the number of transmit antennas at the BS.Non-orthogonal multiple access (NOMA) can improve the throughput of users withpoorer channel conditions by compromising their own privacy because other userswith better channel conditions can decode the information of users in poorerchannel state. NOMA still prefers that the number of users is less than thenumber of antennas at the BS transmitter. This paper resolves such issues byallocating separate fractional time slots for serving the users with similarchannel conditions. This enables the BS to serve more users within the timeunit while the privacy of each user is preserved. The fractional times andbeamforming vectors are jointly optimized to maximize the system's throughput.An efficient path-following algorithm, which invokes a simple convex quadraticprogram at each iteration, is proposed for the solution of this challengingoptimization problem. Numerical results confirm its versatility.
Ni, W, Abolhasan, M, Hagelstein, B, Liu, RP & Wang, X 2017, 'A New Trellis Model for MAC Layer Cooperative Retransmission Protocols', IEEE Transactions on Vehicular Technology, vol. 66, no. 4, pp. 3448-3461.
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© 1967-2012 IEEE. Comparison studies on timer-based distributed cooperative retransmission protocols are challenging, given a variety of backoff techniques. We propose a new unified model, which can characterize a wide range of cooperative retransmission protocols. The key idea is a new trellis diagram that extrapolates the retransmission probabilities in each timeslot to the entire cooperative process. Following the trellis, performance metrics, such as success rate and collision intensity, can be derived in a structured manner. The new trellis model, coupled with Markov techniques, can be also extended to analyze the distributed binary exponential backoff processes of cooperative retransmissions. Confirmed by simulations, the proposed trellis model accurately reveals the impact of the relays' relative locations and density on different protocols. Our model also has the potential to be used as a management tool to adaptively configure protocol parameters.
Ni, W, He, J, Wang, H & Liu, T 2017, 'Association of Platelet Membrane Glycoprotein HPA-2a/b, GP VI T13254C, and GP IbαVNTR Polymorphisms with Risk of Coronary Artery Disease: A Meta-Analysis', BioMed Research International, vol. 2017, pp. 1-8.
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Background and Aims. Recently, controversial results have been reported regarding the association of the polymorphisms of platelet membrane glycoproteins (HPA-2a/b, GP VI T13254C, and GP IbαVNTR) with coronary artery disease (CAD). We performed this meta-analysis to further assess the polymorphisms of platelet membrane glycoproteins with a risk of CAD.Methods. A systematic electronic literature search was conducted in Embase, Cochrane Library, PubMed, and the Chinese Biomedical Literature Database (CBM). Analyses were performed using the Cochrane software package Review Manager 5.2 and Stata 12.0 software package.Results. Twenty-nine full-text articles were included in the meta-analysis. Based on random-effects meta-analysis, a significant association between the HPA-2a/b polymorphism and CAD was identified (allele model: odds ratio = 1.43, 95% confidence interval = 1.07–1.91; dominant genetic model: odds ratio = 1.57, 95% confidence interval = 1.08–2.28). Our study showed no association between the GP VI T13254C polymorphism and CAD in either a random-effects model or a fixed-effects model. Furthermore, there was no evidence to suggest that the GP IbαVNTR polymorphism was associated with CAD in any of the genetic analysis models.Conclusions. The HPA-2a/b polymorphism correlated significantly with a risk of CAD, and the HPA-2b allele and the HPA-2ab + HPA-2bb genotype may increase the risk of CAD. There was no evidence to suggest that polymorphisms of GP VI T13254C and GP IbαVNTR were associated with CAD.
Ni, W, Wu, W & Li, K 2017, 'A message efficient intersection control algorithm for intelligent transportation in smart cities', Future Generation Computer Systems, vol. 76, pp. 339-349.
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Ni, W, Ye, J, Guo, Y, Cheng, C, Lin, Z, Li, Y, Wang, H, Yu, Y, Li, Q, Huang, S, Shao, Z & Wang, C 2017, 'Decisive role of mixed‐valence structure in colossal dielectric constant of LaFeO3', Journal of the American Ceramic Society, vol. 100, no. 7, pp. 3042-3049.
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AbstractThe role of mixed‐valence structure in colossal dielectric constant (CDC) behavior has been investigated in LaFeO3 ceramics by tuning the ratio of Fe2+/Fe3+ through substituting Al for Fe. The ratio of Fe2+/Fe3+ is decreased gradually from 1.0 to 0.0 by increasing the concentration of Al3+. Two clear‐cut correlations have been found: (i) the relationship between the CDC behavior and the ratio of Fe2+/Fe3+ follows an exponential function and (ii) the activation energy of the polaron relaxation is proportional to , where is the intrinsic dielectric constant. These findings underscore the role of the mixed‐valence structure in CDC behavior and suggest that adjusting the mixed‐valence structure through doping/alloying can be a promising strategy to achieve superior CDC behavior in transition‐metal oxides.
Nicholson, AP, Irfansyah, AN, Jenkins, J, Hamilton, TJ & Lehmann, T 2017, 'A Statistical Design Approach Using Fixed and Variable Width Transconductors for Positive-Feedback Gain-Enhancement OTAs', IEEE Transactions on Very Large Scale Integration (VLSI) Systems, vol. 25, no. 6, pp. 1966-1977.
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© 2017 IEEE. The positive-feedback gain-enhancement operational transconductance amplifier (OTA) design is a promising architecture to scale into deep submicron CMOS. Ever smaller CMOS process nodes require analog circuit designs that can overcome the area-power-matching relation. We introduce a Nauta OTA with a split architecture consisting of fixed width and digitally programmable variable width transconductors utilizing the minimum grid-spacing of the CMOS process enabling an active mismatch cancelation technique. A variation-aware statistical design practice is introduced to analyze the sizing of transconductors, computing code-word solutions for statistically likely solutions, and estimating average maximum dc gain over the entire code-space of many simulated OTAs. Prototypes of a 8-bit differential OTA in 180-nm CMOS designed using the Nauta structure fixed width and digitally programmable variable width architecture achieves an average maximum dc gain of 60 dB, simulated unity gain frequency of 4.6 GHz, and a figure-of-merit of 1 GHz/mW.
Nimmy, SF, Kamal, MS, Hossain, MI, Dey, N, Ashour, AS & Shi, F 2017, 'Neural Skyline Filtering for Imbalance Features Classification', International Journal of Computational Intelligence and Applications, vol. 16, no. 03, pp. 1750019-1750019.
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In the current digitalized era, large datasets play a vital role in features extractions, information processing, knowledge mining and management. Sometimes, existing mining approaches are not sufficient to handle large volume of datasets. Biological data processing also suffers for the same issue. In the present work, a classification process is carried out on large volume of exons and introns from a set of raw data. The proposed work is designed into two parts as pre-processing and mapping-based classification. For pre-processing, three filtering techniques have been used. However, these traditional filtering techniques face difficulties for large datasets due to the long required time during large data processing as well as the large required memory size. In this regard, a mapping-based neural skyline filtering approach is designed. Randomized algorithm performed the mapping for large volume of datasets based on objective function. The objective function determines the randomized size of the datasets according to the homogeneity. Around 200 million DNA base pairs have been used for experimental analysis. Experimental result shows that mapping centric filtering outperforms other filtering techniques during large data processing.
Niyato, D, Hoang, DT, Wang, P & Han, Z 2017, 'Cyber Insurance for Plug-In Electric Vehicle Charging in Vehicle-to-Grid Systems', IEEE Network, vol. 31, no. 2, pp. 38-46.
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© 1986-2012 IEEE. V2G systems bring many benefits to power systems in stabilizing energy demand and supply fluctuations as well as to PEV users in reducing energy costs. To achieve the maximum efficiency of V2G systems, data communication plays an important role. However, it is subject to cyber attack and failure, which hinder the effectiveness of V2G systems. In this article, we introduce a novel concept of using cyber insurance to transfer cyber risk from a user to a third party in PEV charging. We first introduce V2G systems and briefly discuss the cyber risks. Additionally, the basic concepts of cyber insurance are presented. We then introduce the use of cyber insurance to remove the risk of paying high energy costs of PEV charging due to the unavailability of data communication. We show that the PEV user can achieve the maximum benefit in deciding to charge its PEV and to buy insurance.
Nuryani, NA, Harjito, B, Yahya, I, Solikhah, M, Chai, R & Lestari, A 2017, 'Atrial fibrillation detection using support vector machine and electrocardiographic descriptive statistics', International Journal of Biomedical Engineering and Technology, vol. 24, no. 3, pp. 225-225.
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This paper proposes a new technique for detecting atrial fibrillation (AF). The method employs electrocardiographic features and support vector machine (SVM). The features include descriptive statistics of electrocardiographic RR interval. The RR interval is the distance in time between two consecutive R-peaks of electrocardiogram. AF detections using SVM with different electrocardiographic features and different SVM free parameters are explored. Employing SVM with the optimal free parameters and all the proposed electrocardiographic features, we find an AF detection technique with a comparable performance. The best performance obtained by the technique is 98.47% and 97.84%, in terms of sensitivity and specificity.
Ovalle, A, Hably, A, Bacha, S, Ramos, G & Hossain, JM 2017, 'Escort Evolutionary Game Dynamics Approach for Integral Load Management of Electric Vehicle Fleets', IEEE Transactions on Industrial Electronics, vol. 64, no. 2, pp. 1358-1369.
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This paper proposes an application of an evolutionary game dynamics called the escort dynamics (ED) for the decentralized load management of plug-in electric vehicles (PEV). Different from earlier contributions, in the present approach, PEVs work together in a fair scheme in order to provide several ancillary services to the grid: Load shifting, active power balancing, and partial supply of reactive power demand on each phase of the distribution transformer. Meanwhile, batteries are guaranteed to be fully charged according to the constraints imposed by the owners. In the proposed formulation, chargers can be either three phase or single phase; however, in this paper, only three-phase chargers are considered. The key concepts behind ED, especially for escort functions, are provided at the beginning of this paper. Based on these concepts, the assumptions and analogies followed for the construction of the proposed approach are explained in detail, especially for the proposed definition of escort functions. A multipopulation scenario is proposed for the interaction of several PEVs using local ED routines. This interaction among populations follows another well-known evolutionary game dynamics called the best reply dynamics. Performance is evaluated using real data measured from a distribution transformer from the SOREA utility grid company in the region of Savoie, France.
Palmer, S, Litvinova, K, Dunaev, A, Yubo, J, McGloin, D & Nabi, G 2017, 'Optical redox ratio and endogenous porphyrins in the detection of urinary bladder cancer: A patient biopsy analysis', Journal of Biophotonics, vol. 10, no. 8, pp. 1062-1073.
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© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Bladder cancer is among the most common cancers in the UK and conventional detection techniques suffer from low sensitivity, low specificity, or both. Recent attempts to address the disparity have led to progress in the field of autofluorescence as a means to diagnose the disease with high efficiency, however there is still a lot not known about autofluorescence profiles in the disease. The multi-functional diagnostic system “LAKK-M” was used to assess autofluorescence profiles of healthy and cancerous bladder tissue to identify novel biomarkers of the disease. Statistically significant differences were observed in the optical redox ratio (a measure of tissue metabolic activity), the amplitude of endogenous porphyrins and the NADH/porphyrin ratio between tissue types. These findings could advance understanding of bladder cancer and aid in the development of new techniques for detection and surveillance. (Figure presented.).
Pham, TT, Leong, PHW, Robinson, PD, Gutzler, T, Jee, AS, King, GG & Thamrin, C 2017, 'Automated quality control of forced oscillation measurements: respiratory artifact detection with advanced feature extraction', Journal of Applied Physiology, vol. 123, no. 4, pp. 781-789.
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The forced oscillation technique (FOT) can provide unique and clinically relevant lung function information with little cooperation with subjects. However, FOT has higher variability than spirometry, possibly because strategies for quality control and reducing artifacts in FOT measurements have yet to be standardized or validated. Many quality control procedures rely on either simple statistical filters or subjective evaluation by a human operator. In this study, we propose an automated artifact removal approach based on the resistance against flow profile, applied to complete breaths. We report results obtained from data recorded from children and adults, with and without asthma. Our proposed method has 76% agreement with a human operator for the adult data set and 79% for the pediatric data set. Furthermore, we assessed the variability of respiratory resistance measured by FOT using within-session variation (wCV) and between-session variation (bCV). In the asthmatic adults test data set, our method was again similar to that of the manual operator for wCV (6.5 vs. 6.9%) and significantly improved bCV (8.2 vs. 8.9%). Our combined automated breath removal approach based on advanced feature extraction offers better or equivalent quality control of FOT measurements compared with an expert operator and computationally more intensive methods in terms of accuracy and reducing intrasubject variability. NEW & NOTEWORTHY The forced oscillation technique (FOT) is gaining wider acceptance for clinical testing; however, strategies for quality control are still highly variable and require a high level of subjectivity. We propose an automated, complete breath approach for removal of respiratory artifacts from FOT measurements, using feature extraction and an interquartile range filter. Our approach offers better or equivalent performance compared with an expert operator, in terms of accuracy and reducing intrasubject variability.
Pham, TT, Moore, ST, Lewis, SJG, Nguyen, DN, Dutkiewicz, E, Fuglevand, AJ, McEwan, AL & Leong, PHW 2017, 'Freezing of Gait Detection in Parkinson's Disease: A Subject-Independent Detector Using Anomaly Scores', IEEE Transactions on Biomedical Engineering, vol. 64, no. 11, pp. 2719-2728.
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© 2012 IEEE. Freezing of gait (FoG) is common in Parkinsonian gait and strongly relates to falls. Current clinical FoG assessments are patients' self-report diaries and experts' manual video analysis. Both are subjective and yield moderate reliability. Existing detection algorithms have been predominantly designed in subject-dependent settings. In this paper, we aim to develop an automated FoG detector for subject independent. After extracting highly relevant features, we apply anomaly detection techniques to detect FoG events. Specifically, feature selection is performed using correlation and clusterability metrics. From a list of 244 feature candidates, 36 candidates were selected using saliency and robustness criteria. We develop an anomaly score detector with adaptive thresholding to identify FoG events. Then, using accuracy metrics, we reduce the feature list to seven candidates. Our novel multichannel freezing index was the most selective across all window sizes, achieving sensitivity (specificity) of 96% (79%). On the other hand, freezing index from the vertical axis was the best choice for a single input, achieving sensitivity (specificity) of 94% (84%) for ankle and 89% (94%) for back sensors. Our subject-independent method is not only significantly more accurate than those previously reported, but also uses a much smaller window (e.g., 3 s versus 7.5 s) and/or lower tolerance (e.g., 0.4 s versus 2 s).
Pham, TT, Thamrin, C, Robinson, PD, McEwan, AL & Leong, PHW 2017, 'Respiratory Artefact Removal in Forced Oscillation Measurements: A Machine Learning Approach', IEEE Transactions on Biomedical Engineering, vol. 64, no. 8, pp. 1679-1687.
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Goal: Respiratory artefact removal for the
forced oscillation technique can be treated as an anomaly
detection problem. Manual removal is currently considered
the gold standard, but this approach is laborious and subjective.
Most existing automated techniques used simple
statistics and/or rejected anomalous data points. Unfortunately,
simple statistics are insensitive to numerous artefacts,
leading to low reproducibility of results. Furthermore,
rejecting anomalous data points causes an imbalance between
the inspiratory and expiratory contributions. Methods:
From a machine learning perspective, such methods
are unsupervised and can be considered simple feature extraction.
We hypothesize that supervised techniques can
be used to find improved features that are more discriminative
and more highly correlated with the desired output.
Features thus found are then used for anomaly detection
by applying quartile thresholding, which rejects complete
breaths if one of its features is out of range. The thresholds
are determined by both saliency and performance
metrics rather than qualitative assumptions as in previous
works. Results: Feature ranking indicates that our new landmark
features are among the highest scoring candidates
regardless of age across saliency criteria. F1-scores, receiver
operating characteristic, and variability of the mean
resistance metrics show that the proposed scheme outperforms
previous simple feature extraction approaches. Our
subject-independent detector, 1IQR-SU, demonstrated approval
rates of 80.6% for adults and 98% for children, higher
than existing methods. Conclusion: Our new features are
more relevant. Our removal is objective and comparable to
the manual method. Significance: This is a critical work to
automate forced oscillation technique quality control.
Phung, MD, Quach, CH, Dinh, TH & Ha, Q 2017, 'Enhanced discrete particle swarm optimization path planning for UAV vision-based surface inspection', Automation in Construction, vol. 81, pp. 25-33.
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© 2017 In built infrastructure monitoring, an efficient path planning algorithm is essential for robotic inspection of large surfaces using computer vision. In this work, we first formulate the inspection path planning problem as an extended travelling salesman problem (TSP) in which both the coverage and obstacle avoidance were taken into account. An enhanced discrete particle swarm optimization (DPSO) algorithm is then proposed to solve the TSP, with performance improvement by using deterministic initialization, random mutation, and edge exchange. Finally, we take advantage of parallel computing to implement the DPSO in a GPU-based framework so that the computation time can be significantly reduced while keeping the hardware requirement unchanged. To show the effectiveness of the proposed algorithm, experimental results are included for datasets obtained from UAV inspection of an office building and a bridge.
Puthal, D, Mohanty, SP, Nanda, P & Choppali, U 2017, 'Building Security Perimeters to Protect Network Systems Against Cyber Threats [Future Directions]', IEEE Consumer Electronics Magazine, vol. 6, no. 4, pp. 24-27.
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© 2012 IEEE. Due to the wide variety of devices used in computer network systems, cybersecurity plays a major role in securing and improving the performance of the network or system. Although cybersecurity has received a large amount of global interest in recent years, it remains an open research space. Current security solutions in network-based cyberspace provide an open door to attackers by communicating first before authentication, thereby leaving a black hole for an attacker to enter the system before authentication. This article provides an overview of cyberthreats, traditional security solutions, and the advanced security model to overcome current security drawbacks.
Qi, G & Zhang, J 2017, 'Energy cycle and bound of Qi chaotic system', Chaos, Solitons & Fractals, vol. 99, pp. 7-15.
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The Qi chaotic system is transformed into a Kolmogorov-type system, thereby facilitating the analysis of energy exchange in its different forms. Regarding four forms of energy, the vector field of this chaotic system is decomposed into four forms of torque: inertial, internal, dissipative, and external. The rate of change of the Casimir function is equal to the exchange power between the dissipative energy and the supplied energy. The exchange power governs the orbital behavior and the cycling of energy. With the rate of change of Casimir function, a general bound and least upper bound of the Qi chaotic attractor are proposed. A detailed analysis with illustrations is conducted to uncover insights, in particular, cycling among the different types of energy for this chaotic attractor and key factors producing the different types of dynamic modes.
Qi, J & Lu, DD-C 2017, 'A Preventive Approach for Solving Battery Imbalance Issue by Using a Bidirectional Multiple-Input Ćuk Converter Working in DCVM', IEEE Transactions on Industrial Electronics, vol. 64, no. 10, pp. 7780-7789.
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© 1982-2012 IEEE. State of charge (SoC) imbalance among batteries in a battery energy storage system (BESS) degrades the system performance and may lead to safety issue. A bidirectional multiple-input Ćuk converter for the BESS is proposed to prevent batteries from SoC imbalance issue. Compared to the traditional BESS, the battery balancing and voltage/current regulation subsystems are combined into one. As a result, the overall system complexity is significantly reduced. Moreover, the current flow of each battery is self-adjusted according to its terminal voltage. Therefore, the system does not require sophisticated control algorithm for battery balancing. Moreover, the proposed system has no energy dumping and energy transferring between batteries, which avoids unnecessary energy lose. Due to the nature of multiple-input converter structure, the proposed system can handle certain component failure. The proposed approach of designing the BESS has been investigated through simulation and validated experimentally.
Qiao, M, Xu, RYD, Bian, W & Tao, D 2017, 'Fast Sampling for Time-Varying Determinantal Point Processes', ACM Transactions on Knowledge Discovery from Data, vol. 11, no. 1, pp. 1-24.
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Determinantal Point Processes (DPPs) are stochastic models which assign each subset of a base dataset with a probability proportional to the subset’s degree of diversity. It has been shown that DPPs are particularly appropriate in data subset selection and summarization (e.g., news display, video summarizations). DPPs prefer diverse subsets while other conventional models cannot offer. However, DPPs inference algorithms have a polynomial time complexity which makes it difficult to handle large and time-varying datasets, especially when real-time processing is required. To address this limitation, we developed a fast sampling algorithm for DPPs which takes advantage of the nature of some time-varying data (e.g., news corpora updating, communication network evolving), where the data changes between time stamps are relatively small. The proposed algorithm is built upon the simplification of marginal density functions over successive time stamps and the sequential Monte Carlo (SMC) sampling technique. Evaluations on both a real-world news dataset and the Enron Corpus confirm the efficiency of the proposed algorithm.
Qin, C, Ni, W, Tian, H & Liu, RP 2017, 'Fronthaul Load Balancing in Energy Harvesting Powered Cloud Radio Access Networks', IEEE Access, vol. 5, pp. 7762-7775.
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© 2013 IEEE. Enhanced with wireless power transfer capability, cloud radio access network (C-RAN) enables energy-restrained mobile devices to function uninterruptedly. Beamforming of C-RAN has potential to improve the efficiency of wireless power transfer, in addition to transmission data rates. In this paper, we design the beamforming jointly for data transmission and energy transfer, under finite fronthaul capacity of C-RAN. A non-convex problem is formulated to balance the fronthaul requirements of different remote radio heads (RRHs). Norm approximations and relaxations are carried out to convexify the problem to second-order cone programming (SOCP). To improve the scalability of the design to large networks, we further decentralize the SOCP problem using the alternating direction multiplier method (ADMM). A series of reformulations and transformations are conducted, such that the resultant problem conforms to the state-of-The-Art ADMM solver and can be efficiently solved in real time. Simulation results show that the distributed algorithm can remarkably reduce the time complexity without compromising the fronthaul load balancing of its centralized counterpart. The proposed algorithms can also reduce the fronthaul bandwidth requirements by 25% to 50%, compared with the prior art.
Qin, C, Ni, W, Tian, H & Liu, RP 2017, 'Joint Rate Maximization of Downlink and Uplink in Multiuser MIMO SWIPT Systems', IEEE Access, vol. 5, pp. 3750-3762.
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© 2013 IEEE. Beamforming has the potential to improve the efficiency of simultaneous wireless information and power transfer (SWIPT) systems. Existing beamforming techniques have been focused on the downlink of SWIPT systems. In this paper, we optimize the beamformers and transmit duration to maximize the weighted sum rate of both the downlink and uplink in a multiuser multiple-input multiple-output (MIMO) SWIPT system. Specifically, we formulate and transform the problem into a weighted sum mean square error minimization, conduct difference of convex programming to decouple the downlink and uplink, and convert the problem to quadratic programming (QP), which can be solved iteratively in a centralized fashion. We also decentralize the QP problem using dual decompositions, and reduce the time-complexity without compromising the data rate. Moreover, our algorithms are extended to the case under imperfect channel state information. Confirmed by simulations, the proposed decentralization can dramatically reduce the time-complexity by orders of magnitude. The scalability of the proposed approach can be substantially enhanced to support medium to large networks.
Rabiul Islam, M, Xu, W, Guo, Y & Ma, K 2017, 'Solar Photovoltaic Power Plants', International Journal of Photoenergy, vol. 2017, pp. 1-2.
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Rafi, FHM, Hossain, MJ & Lu, J 2017, 'Improved Neutral Current Compensation With a Four-Leg PV Smart VSI in a LV Residential Network', IEEE Transactions on Power Delivery, vol. 32, no. 5, pp. 2291-2302.
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Raka, A, Naik, G & Chai, R 2017, 'Computational Algorithms Underlying the Time-Based Detection of Sudden Cardiac Arrest via Electrocardiographic Markers', Applied Sciences, vol. 7, no. 9, pp. 954-954.
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Early detection of sudden cardiac arrest (SCA) is critical to prevent serious repercussion such as irreversible neurological damage and death. Currently, the most effective method involves analyzing electrocardiogram (ECG) features obtained during ventricular fibrillation. In this study, data from 10 normal patients and 10 SCA patients obtained from Physiobank were used to statistically compare features, such as heart rate, R-R interval duration, and heart rate variability (HRV) features from which the HRV features were then selected for classification via linear discriminant analysis (LDA) and linear and fine Gaussian support vector machines (SVM) in order to determine the ideal time-frame in which SCA can be accurately detected. The best accuracy was obtained at 2 and 8 min prior to SCA onset across all three classifiers. However, accuracy rates of 75–80% were also obtained at time-frames as early as 50 and 40 min prior to SCA onset. These results are clinically important in the field of SCA, as early detection improves overall patient survival.
Rana, M, Li, L & Su, SW 2017, 'Distributed State Estimation Over Unreliable Communication Networks With an Application to Smart Grids', IEEE Transactions on Green Communications and Networking, vol. 1, no. 1, pp. 89-96.
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© 2017 IEEE. In contrast to the traditional centralized power system state estimation methods, this paper investigates the interconnected optimal filtering problem for distributed dynamic state estimation considering packet losses. Specifically, the power system incorporating microgrids is modeled as a state-space linear equation where sensors are deployed to obtain measurements. Basically, the sensing information is transmitted to the energy management system through a lossy communication network where measurements are lost. This can seriously deteriorate the system monitoring performance and even lose network stability. Second, as the system states are unavailable, so the estimation is essential to know the overall operating conditions of the electricity network. Availability of the system states provides designers with an accurate picture of the power network, so a suitable control strategy can be applied to avoid massive blackouts due to losing network stability. Particularly, the proposed estimator is based on the mean squared error between the actual state and its estimate. To obtain the distributed estimation, the optimal local and neighboring gains are computed to reach a consensus estimation after exchanging their information with the neighboring estimators. Then, the convergence of the developed algorithm is theoretically proved. Afterward, a distributed controller is designed based on the semidefinite programming approach. Simulation results demonstrate the accuracy of the developed approaches under the condition of missing measurements.
Rana, MM & Li, L 2017, 'Renewable microgrid state estimation using the Internet of Things communication network', 2017 19th International Conference on Advanced Communication Technology (ICACT), vol. 5, no. 3, pp. 823-829.
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Given the huge concerns all over the world regarding
carbon emissions from fossil fuels, energy crisis and
global warming, the renewable distributed energy resources
(DERs) are going to be integrated in electricity grids, which will
make the energy supply more reliable and decrease transmission
losses. Regrettably, one of the main practical defies in smart
grid planning, control and operation with DERs is the voltage
regulation at the distribution field level. This problem motivates
the deployment of sensors and actuators in electricity grids so
that the voltage regulation can be controlled at the desired level.
To do that the measurements from the renewable microgrid state
information is transmitted to an energy management center via
the internet of things (IoT) based communication network. In
other words, the proposed IoT communication infrastructure
provides an opportunity to address the voltage regulation challenge
by offering the two-way communication links for microgrid
state information collection and estimation. Based on this smart
grid communication infrastructure, we propose a Kalman filter
based state estimation method for voltage regulation of the
microgrid. Finally, the effectiveness of the Kalman filter based
state estimation method is illustrated using the linear state space
model of a microgrid incorporating DERs.
Rana, MM, Li, L & Su, S 2017, 'Design a distributed controller for microgrids', International Journal of Innovative Computing, Information and Control, vol. 13, no. 3, pp. 1055-1060.
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This paper addresses the problem of distributed energy management system (EMS) design considering network-induced delays. First of all, the distribution power network incorporating solar panels is modelled as a discrete-time linear state-space equation and its measurements/control information is obtained using a set of sensors and actuators. These electronic devices send the observation information to the EMS via un-reliable communication links. In order to stabilize the system, we propose discrete-time distributed static output feedback control strategies based on the linear matrix inequality and semi definite programming approaches. Using the Taylor series method, delays are integrated into the closed loop system so that the proposed controller runs with less energy resources and computation. Simulation results demonstrate that the proposed method is able to stabilize the system in a fairly short time.
Rana, MM, Li, L & Su, SW 2017, 'Controlling the renewable microgrid using semidefinite programming technique', International Journal of Electrical Power & Energy Systems, vol. 84, pp. 225-231.
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© 2016 Given the significant concerns regarding carbon emissions from fossil fuels, global warming and energy crisis, renewable distributed energy resources (DERs) are going to be integrated in smart grids, which will make the energy supply more reliable and decrease the costs and transmission losses. Unfortunately, one of the key technical challenges in power system planning, control and operation with DERs is the voltage regulation at the distribution level. This problem stimulates the deployment of smart sensors and actuators in smart grids so that the voltage can be stabilized. The observation from the microgrid incorporating DERs is transmitted to the control center via wireless communication systems. In other words, the proposed communication infrastructure provides an opportunity to address the voltage regulation challenge by offering the two-way communication links for microgrid state information collection, estimation and stabilization. Based on the communication infrastructure, we propose a least square based Kalman filter algorithm for state estimation and an optimal feedback control framework for stabilizing the microgrid states. Specifically, we propose to optimize the performance index by using semidefinite programming techniques in the context of smart grid applications. At the end, the efficacy of the developed approaches is demonstrated using a microgrid incorporating multiple DERs.
Rana, MM, Li, L & Su, SW 2017, 'Distributed State Estimation of Smart Grids with Packet Losses', Asian Journal of Control, vol. 19, no. 4, pp. 1306-1315.
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AbstractThis paper explores the problem of distributed state estimation including packet losses for the environment‐friendly renewable microgrid incorporating electricity generating circuits. The problem is becoming critical due to the global warming, increasing green house gas emissions, and practical infeasibility with computational burden of the large‐scale centralized power system monitoring. To address the impending problem, a novel distributed state estimation algorithm is derived in the context of smart grids. Specifically, after modelling the microgrid, this paper proposes a local state estimation algorithm considering packet losses. Then a novel optimal weighting factor calculation method for the global state estimation is proposed. Particularly, it can automatically adjust the optimal weighting factors for different sensor measurements based on the observation. Simulations results show that the desired state estimation accuracy is achieved.
Rufangura, P & Sabah, C 2017, 'Graphene-based wideband metamaterial absorber for solar cells application', Journal of Nanophotonics, vol. 11, no. 3, pp. 036008-036008.
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A wideband metamaterial (MTM) absorber based on a concentric ring resonator is discussed at visible frequencies. The proposed structure offers a wideband absorption response, where absorption of <70% is gained for the frequency ranging from 537.91 to 635.73 THz. The analysis is conducted on the components of the proposed structure to understand the origin of wideband absorption. Furthermore, a graphene monolayer sheet is integrated to the proposed MTM absorber to optimize its absorptivity, where the studies show enhancement of the absorptivity of the proposed structure up to 26% from its initial absorptivity. MTM absorbers of this kind have potential applications in solar cells.
Saadat, A, Ni, W & Vesilo, R 2017, 'Collaborative Spectrum Sharing Through Non-Collaborative Gaming for Next-Generation Small Cells', IEEE Access, vol. 5, pp. 10182-10192.
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© 2013 IEEE. Existing spectrum-sharing schemes either allow the secondary-network users (SUs) to utilize the spectrum when primary-network users (PUs) remain idle, or require the SUs to coordinate with the PUs, causing signaling overhead. In this paper, we propose a game-theoretic spectrum-sharing scheme, which enables the SUs and PUs to utilize the spectrum simultaneously, without compromising the quality of service (QoS) of the PUs and ensuring reduced signaling overhead. We formulate a multi-priority non-cooperative power-control game by considering a scenario where multiple small cell base stations belonging to either the primary network or secondary network utilize the available spectrum resources at the same time. The base stations are empowered to adjust their transmit powers in an automated manner based on measured interference, until their transmit powers are stabilized. As a key idea, a game parameter, dynamic price coefficient, is designed to give the primary network priority over the secondary network for accessing the spectrum. We determine appropriate bounds for the game parameters to ensure the existence and uniqueness of the Nash equilibrium of the proposed game. Furthermore, we propose a novel dual-mode solution to reduce the real-time signaling overhead between the networks, by minimizing the information exchange during the game required to reach an equilibrium point. Extensive simulation results are presented to prove the convergence of the game to a Nash equilibrium, along with a throughput performance analysis.
Saputra, YM & Yun, J-H 2017, 'E-MICE: Energy-Efficient Concurrent Exploitation of Multiple Wi-Fi Radios', IEEE Transactions on Mobile Computing, vol. 16, no. 7, pp. 1870-1880.
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© 2002-2012 IEEE. The concurrent use of multiple Wi-Fi radios in individual frequency channels is a solution readily available today to the increase of a mobile station's communication capacity, but at the expense of occasional performance deterioration (when the heterogeneity of capacity between interfaces gets severe) and additional power consumption. This paper proposes a mobile-side solution for the concurrent use of multiple radios in a performance-aware and energy-efficient manner, with which a mobile station activates and deactivates radio interfaces dynamically according to traffic demands and a predicted capacity gain. To this end, the proposed solution is composed of multiple prediction algorithms and a control algorithm. Prediction when activating an additional radio interface is relatively difficult since no information of the disabled interface's current status (and the corresponding frequency channel's) is available at the time of prediction. Our experiments show that, despite different types and used channels, different radio interfaces have a strong correlation of received signal strengths and used PHY rates between them. Based on this observation, the proposed solution learns a correlation pattern between interfaces whenever multiple interfaces are active and makes prediction of the coverage, expected PHY rate and capacity impact of an inactive interface based on the learned correlation with a currently active interface. The design of the prediction algorithms are based on a simple or machine-learning technique (SVM). The control algorithm then keeps monitoring the utilization of active interfaces and, if any of them has utilization over a threshold, checks if each inactive interface is within coverage and a valid rate range based on an active interface's received signal strength. Finally, an action of a configuration change (either activation, deactivation, or no change) selected based on the prediction of the resulting capacity is app...
Schell, AW, Takashima, H, Tran, TT, Aharonovich, I & Takeuchi, S 2017, 'Coupling Quantum Emitters in 2D Materials with Tapered Fibers', ACS Photonics, vol. 4, no. 4, pp. 761-767.
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© 2017 American Chemical Society. Realization of integrated photonic circuits on a single chip requires controlled manipulation and integration of solid-state quantum emitters with nanophotonic components. Previous works focused on emitters embedded in a three-dimensional crystal, such as nanodiamonds or quantum dots. In contrast, in this work we demonstrate coupling of a single emitter in a two-dimensional (2D) material, namely, hexagonal boron nitride, with a tapered optical fiber and find a collection efficiency of the system of 10%. Furthermore, due to the single dipole character of the emitter, we were able to analyze the angular emission pattern of the coupled system via back focal plane imaging. The good coupling efficiency to the tapered fiber even allows excitation and detection in a fully fiber coupled way, yielding a true integrated system. Our results provide evidence of the feasibility to efficiently integrate quantum emitters in 2D materials with photonic structures.
Setlhaolo, D, Sichilalu, S & Zhang, J 2017, 'Residential load management in an energy hub with heat pump water heater', Applied Energy, vol. 208, pp. 551-560.
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© 2017 Elsevier Ltd Today, as a consequence of the growing installation of efficient technologies, such as combined heat and power (CHP) as a co-generation, the integration of electricity through grid supply, Photovoltaic (PV) and energy storage systems as an integrated network is attracting a lot of attention in smart grid applications. To model the interaction among electricity and natural gas, the energy hub framework is adopted to determine a modelling procedure for such multi-carrier energy systems. This paper presents a residential energy hub model for a smart home as a modified framework of conventional energy hubs in a smart grid with consideration of heat pump water heater, coordination of sources and carbon emissions. Therefore, this study is twofold; the first part optimizes the operation of the combined CHP, Photovoltaic and storage system under dynamic pricing. Since residential load management plays a key role in realizing household demand response programs in a smart grid, performing optimal load management in the proposed residential energy hub model is also studied in this paper. To achieve this, the optimization problem is extended by considering modelling of a heat pump water heater. It is also found out that CO 2 signal could give customers an environmental motivation to shift or reduce loads during peak hours, as it would enable co-optimization of electricity consumption costs and carbon emissions reductions.
Sheng, Z, Tuan, HD, Duong, TQ & Poor, HV 2017, 'Joint Power Allocation and Beamforming for Energy-Efficient Two-Way Multi-Relay Communications', IEEE Transactions on Wireless Communications, vol. 16, no. 10, pp. 6660-6671.
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This paper considers the joint design of user power allocation and relaybeamforming in relaying communications, in which multiple pairs ofsingle-antenna users exchange information with each other via multiple-antennarelays in two time slots. All users transmit their signals to the relays in thefirst time slot while the relays broadcast the beamformed signals to all usersin the second time slot. The aim is to maximize the system's energy efficiency(EE) subject to quality-of-service (QoS) constraints in terms of exchangethroughput requirements. The QoS constraints are nonconvex with many nonlinearcross-terms, so finding a feasible point is already computationallychallenging. The sum throughput appears in the numerator while the totalconsumption power appears in the denominator of the EE objective function. Theformer is a nonconcave function and the latter is a nonconvex function, makingfractional programming useless for EE optimization. Nevertheless, efficientiterations of low complexity to obtain its optimized solutions are developed.The performances of the multiple-user and multiple-relay networks under variousscenarios are evaluated to show the merit of the paper development.
Sheng, Z, Tuan, HD, Nguyen, HH & Debbah, M 2017, 'Optimal Training Sequences for Large-Scale MIMO-OFDM Systems', IEEE Transactions on Signal Processing, vol. 65, no. 13, pp. 3329-3343.
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© 1991-2012 IEEE. This paper considers the optimal design of training sequences for channel estimation in large-scale multiple-input multiple-output orthogonal frequency-division multiplexing systems. The application scenario of interest is when the number of transmit antennas for the downlink (or the number of receive antennas for the uplink) is large, but not large enough to benefit the asymptotical optimality of using equipower training sequences (e.g., due to practical constraints on deployment costs, space, and antenna size). Under the criterion of minimizing the mean square error of the channel estimate, the optimal design of training sequences for such systems poses a truly large-scale optimization problem, to which existing optimization solvers are not applicable. We develop a fast convex programming (FCP) procedure to find its global optimal solution. In each iteration of the proposed FCP procedure, a solution is found in a scalable and closed form. The singularity and ill-conditionedness of the channel correlation matrices are also exploited to improve the computation efficiency. Furthermore, we also examine the design of reduced-length training sequences and develop a successive quadratic programming procedure to find the solutions. Intensive simulation results are provided to illustrate the performance of our methods.
Sheng, Z, Tuan, HD, Nguyen, HH & Fang, Y 2017, 'Pilot Optimization for Estimation of High-Mobility OFDM Channels', IEEE Transactions on Vehicular Technology, vol. 66, no. 10, pp. 8795-8806.
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© 2017 IEEE. Obtaining channel state information is very crucial for realizing high-performance high-rate wireless communications. For an orthogonal frequency-division multiplexing (OFDM) system operating in a high-mobility environment such as in high-speed trains, a sequence of pilot samples is inserted in each OFDM symbol to track the fast-varying channel responses. For such a high-mobility environment, the design of pilot sequence to minimize the mean squared error (MSE) of the channel estimate under a linear minimum mean squared error (LMMSE) estimator poses a difficult polynomial fractional optimization problem. In this paper, we develop a path-following optimization procedure, which improves the MSE in every iteration and quickly converges at least to its locally-optimal solution. Each iterative solution is given in a closed form with very low computational complexity. The developed path-following procedure can also be adapted to design pilot sequences for the least-square and maximum-likelihood estimators. Extensive simulation results demonstrate the effectiveness and superior performance of the proposed solutions and algorithms when compared to the state-of-The-Art algorithms in the literature.
Sheng, Z, Tuan, HD, Tam, HHM, Nguyen, HH & Fang, Y 2017, 'Energy-efficient precoding in multicell networks with full-duplex base stations', EURASIP Journal on Wireless Communications and Networking, vol. 2017, no. 1, pp. 1-13.
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© 2017, The Author(s). This paper considers multi-input multi-output (MIMO) multicell networks, where the base stations (BSs) are full-duplex transceivers, while uplink and downlink users are equipped with multiple antennas and operate in a half-duplex mode. The problem of interest is to design linear precoders for BSs and users to optimize the network’s energy efficiency. Given that the energy efficiency objective is not a ratio of concave and convex functions, the commonly used Dinkelbach-type algorithms are not applicable. We develop a low-complexity path-following algorithm that only invokes one simple convex quadratic program at each iteration, which converges at least to the local optimum. Numerical results demonstrate the performance advantage of our proposed algorithm in terms of energy efficiency.
Shi, S, Ni, W & Liu, RP 2017, 'Performance analysis of XOR two‐way relay with finite buffers and instant scheduling', IET Communications, vol. 11, no. 4, pp. 507-513.
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© The Institution of Engineering and Technology 2017. This study investigates the performance of practical wireless exclusive OR (XOR) two-way relay (TWR) system, in which finite buffer, lossy wireless channels and non-negligible signalling overhead are considered. Specifically, the authors develop a new analytical model to explicitly characterise the transmissions of both the end-nodes and the relay. The impact of scheduling on the throughput, queuing delay, power consumption and buffer overflow probability of XOR-TWR is evaluated. Validated by simulations, the model can precisely quantify the performance of XOR-TWR and adequately allocate the relay's buffer adapting to the wireless link qualities and signalling overhead.
Shi, Y, Tuan, HD & Apkarian, P 2017, 'Nonconvex spectral optimization algorithms for reduced‐order LPV‐LFT controllers', International Journal of Robust and Nonlinear Control, vol. 27, no. 18, pp. 4421-4442.
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SummaryA novel sequential semi‐definite programming method is developed for optimization subject to rank constraints on matrix‐valued nonlinear functions of matrix decision variables, which arise in reduced‐order linear parameter varying‐linear fractional transformational control synthesis. The global convergence of the method is easily proven without any step size control. An intensive simulation shows the clear advantage of the proposed method over the state‐of‐the‐art nonlinear matrix inequality solvers. Copyright © 2017 John Wiley & Sons, Ltd.
Shi, Y, Tuan, HD, Tuy, H & Su, S 2017, 'Global optimization for optimal power flow over transmission networks', Journal of Global Optimization, vol. 69, no. 3, pp. 745-760.
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© 2017, Springer Science+Business Media New York. The optimal power flow (OPF) problem for power transmission networks is an NP-hard optimization problem with nonlinear constraints on complex bus voltages. The existing nonlinear solvers may fail in yielding a feasible point. Semi-definite relaxation (SDR) could provide the global solution only when the matrix solution of the relaxed semi-definite program (SDP) is of rank-one, which does not hold in general. Otherwise, the point found by SDR is infeasible. High-order SDR has recently been used to find the global solution, which leads to explosive growth of the matrix variable dimension and semi-definite constraints. Consequently, it is suitable only for OPF over very small networks with a few buses. In this paper, we follow our previously developed nonsmooth optimization approach to address this difficult OPF problem, which is an iterative process to generate a sequence of improved points that converge to a global solution in many cases. Each iteration calls an SDP of moderate dimension. Simulations are provided to demonstrate the efficiency of our approach.
Simorangkir, RBVB, Yang, Y, Matekovits, L & Esselle, KP 2017, 'Dual-Band Dual-Mode Textile Antenna on PDMS Substrate for Body-Centric Communications', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 677-680.
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© 2017 IEEE. A dual-band antenna for off- and on-body communications in the 2.45- and 5.8-GHz Industrial, Scientific, and Medical bands is presented. The two radiation characteristics, i.e., patch-like radiation for the off-body link and monopole-like radiation for the on-body link, are achieved by utilizing inherently generated TM11 and TM02 modes of a circular patch antenna. A shorting pin and two arc-shaped slots are employed to tune both modes to the desired operating frequencies. This approach allows a realization of a dual-band dual-mode antenna with a very simple structure, i.e., a single radiator with a simple feed. A further advantage of the proposed antenna is its realization using a silver fabric integrated onto a flexible polydimethylsiloxane substrate that makes it more practical for wearable applications. An experimental investigation of the antenna performance has been carried out in free space and on a semisolid human muscle equivalent phantom, which shows a robust performance against the human body loading effect. When placed on the phantom, the measured bandwidths of 84 and 247 MHz in the 2.45- and 5.8-GHz bands, respectively, are achieved with the corresponding peak gains of 4.16 and 4.34 dBi, indicating a promising candidate for body-centric communications.
Siwakoti, YP & Blaabjerg, F 2017, 'Single Switch Nonisolated Ultra-Step-Up DC–DC Converter With an Integrated Coupled Inductor for High Boost Applications', IEEE Transactions on Power Electronics, vol. 32, no. 11, pp. 8544-8558.
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© 1986-2012 IEEE. This paper introduces a new single-switch nonisolated dc-dc converter with very high voltage gain and reduced semiconductor voltage stress. The converter utilizes an integrated autotransformer and a coupled inductor on the same core in order to achieve a very high voltage gain without using extreme duty cycle. Furthermore, a passive lossless clamp circuit recycles the leakage energy of the coupled magnetics and alleviates the voltage spikes across the main switch. This feature along with low stress on the switching device enables the designer to use a low voltage and low R DS-on MOSFET, which reduces cost, as well as conduction and turn on losses of the switch. The principle of operation, theoretical analysis, and comparison supported by some key simulation and experimental results of a 500 W prototype are presented.
Song, K, Konstantinou, G, Mingli, W, Acuna, P, Aguilera, RP & Agelidis, VG 2017, 'Windowed SHE-PWM of Interleaved Four-Quadrant Converters for Resonance Suppression in Traction Power Supply Systems', IEEE Transactions on Power Electronics, vol. 32, no. 10, pp. 7870-7881.
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© 1986-2012 IEEE. AC electric locomotives that use a number of interleaved four-quadrant converters generate high-frequency switching harmonics which may stimulate certain resonances in traction power supply systems (TPSSs). A windowed selective harmonic elimination pulse-width modulation (SHE-PWM) method is proposed to suppress such resonances. Owing to the windowed design and the precalculated solutions, the proposed method covers the wide potential resonant frequency range and addresses the resonant frequency variation while keeping the low switching frequency of the traction converters. The proposed windowed SHE-PWM is fully tested with a closed-loop controller in a simulation model with the TPSS and the ac electric locomotive. Comparative simulation results show that the windowed SHE-PWM is an effective alternative that overcomes the resonance suppression limitations of the conventional phase-shifted PWM (PS-PWM). The performance of proposed windowed SHE-PWM on an experimental equivalent resonant circuit is further evaluated and compared with PS-PWM. Both simulation and experimental results verify the effectiveness and feasibility of the proposed method.
Sun, H, Ding, C, Jones, B & Guo, YJ 2017, 'A Wideband Base Station Antenna Element With Stable Radiation Pattern and Reduced Beam Squint', IEEE Access, vol. 5, pp. 23022-23031.
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© 2017 IEEE. This paper presents the design procedure, optimization strategy, theoretical analysis, and experimental results of a wideband dual-polarized base station antenna element with superior performance. The proposed antenna element consists of four electric folded dipoles arranged in an octagon shape that are excited simultaneously for each polarization. It provides ±45° slant-polarized radiation that meets all the requirements for base station antenna elements, including stable radiation patterns, low cross polarization level, high port-to-port isolation, and excellent matching across the wide band. The problem of beam squint for beam-tilted arrays is discussed and it is found that the geometry of this element serves to reduce beam squint. Experimental results show that this element has a wide bandwidth of 46.4% from 1.69 to 2.71 GHz with ≥15-dB return loss and 9.8 ± 0.9-dBi gain. Across this wide band, the variations of the half-power-beamwidths of the two polarizations are all within 66.5° ± 5.5°, the port-to-port isolation is >28 dB, the cross-polarization discrimination is >25 dB, and most importantly, the beam squint is <4° with a maximum 10° down-tilt.
Sutton, GJ, Liu, RP & Guo, YJ 2017, 'Harmonising Coexistence of Machine Type Communications With Wi-Fi Data Traffic Under Frame-Based LBT', IEEE Transactions on Communications, vol. 65, no. 9, pp. 4000-4011.
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© 1972-2012 IEEE. The existence of relatively long LTE data blocks within the licensed-assisted access (LAA) framework results in bursty machine-type communications (MTC) packet arrivals, which cause system performance degradation and present new challenges in Markov modeling. We develop an embedded Markov chain to characterize the dynamic behavior of the contention arising from bursty MTC and Wi-Fi data traffic in the LAA framework. Our theoretical model reveals a high-contention phenomenon caused by the bursty MTC traffic, and quantifies the resulting performance degradation for both MTC and Wi-Fi data traffic. The Markov model is further developed to evaluate three potential solutions aiming to alleviate the contention. Our analysis shows that simply expanding the contention window, although successful in reducing congestion, may cause unacceptable MTC data loss. A TDMA scheme instead achieves better MTC packet delivery and overall throughput, but requires centralized coordination. We propose a distributed scheme that randomly spreads the MTC access processes through the available time period. Our model results, validated by simulations, demonstrate that the random spreading solution achieves a near TDMA performance, while preserving the distributed nature of the Wi-Fi protocol. It alleviates the MTC traffic contention and improves the overall throughput by up to 10%.
Tabassum, H, Hossain, E & Hossain, MJ 2017, 'Modeling and Analysis of Uplink Non-Orthogonal Multiple Access (NOMA) in Large-Scale Cellular Networks Using Poisson Cluster Processes', IEEE Transactions on Communications, vol. 65, no. 8, pp. 1-1.
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Using the theory of Poisson cluster process (PCP), this paper provides a framework to analyze multi-cell uplink non-orthogonal multiple access (NOMA) systems. Specifically, we characterize the rate coverage probability of an NOMA user who is at rank m (in terms of the distance from its serving base station) among all users in a cell and the mean rate coverage probability of all users in a cell. Since the signal-to-interference-plus-noise ratio of the m th user relies on efficient successive interference cancellation (SIC), we consider three scenarios, i.e., perfect SIC (in which the signals of m-1 interferers who are stronger than the m th user are decoded successfully), imperfect SIC (in which the signals of m-1 interferers who are stronger than the m th user may or may not be decoded successfully), and imperfect worst case SIC (in which the decoding of the signal of the m th user is always unsuccessful whenever the decoding of its relative m-1 stronger users is unsuccessful). To derive the rate coverage expressions, we first characterize the Laplace transforms of the intra-cluster interferences in closed-form considering various SIC scenarios. The Laplace transform of the inter-cluster interference is then characterized by exploiting distance distributions from geometric probability. The derived expressions are customized for an equivalent OMA system. Finally, numerical results are presented to validate the derived expressions. The worst case SIC assumption provides remarkable simplifications in the mathematical analysis and is found to be highly accurate for higher user target rate requirements. A comparison of Poisson point process-based and PCP-based modeling is also conducted.
Tam, HHM, Tuan, HD, Nasir, AA, Duong, TQ & Poor, HV 2017, 'MIMO Energy Harvesting in Full-Duplex Multi-User Networks', IEEE Transactions on Wireless Communications, vol. 16, no. 5, pp. 3282-3297.
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© 2002-2012 IEEE. This paper considers the efficient design of precoding matrices for sum throughput maximization under throughput quality of service (QoS) constraints and energy harvesting (EH) constraints for energy-constrained devices in a full-duplex (FD) multicell multi-user multiple-input-multiple-output network. Both time splitting (TS) and power splitting are considered to ensure practical EH and information decoding. These problems are quite complex due to non-concave objectives and nonconvex constraints. Especially, with TS, which is implementation-wise quite simple, the problem is even more challenging because the time splitting variable is not only coupled with the downlink throughput function but also coupled with the self-interference in the uplink throughput function. New path-following algorithms are developed for their solutions, which require only a single convex quadratic program for each iteration and ensure rapid convergence. Moreover, the FD EH maximization problem under throughput QoS constraints with TS is also considered. The performance of the proposed algorithms is compared with that of the modified problems assuming half-duplex systems. Finally, the merit of the proposed algorithms is demonstrated through extensive simulations.
TAM, HHM, TUAN, HD, NGO, DT & NGUYEN, HH 2017, 'Precoding Design for Han-Kobayashi's Signal Splitting in MIMO Interference Networks', IEICE Transactions on Communications, vol. E100.B, no. 6, pp. 1010-1016.
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© 2017 The Institute of Electronics, Information and Communication Engineers. For a multiuser multi-input multi-output (MU-MIMO) multicell network, the Han-Kobayashi strategy aims to improve the achievable rate region by splitting the data information intended to a serviced user (UE) into a common message and a private message. The common message is decodable by this UE and another UE from an adjacent cell so that the corresponding intercell interference is cancelled off. This work aims to design optimal precoders for both common and private messages to maximize the network sum-rate, which is a highly nonlinear and nonsmooth function in the precoder matrix variables. Existing approaches are unable to address this difficult problem. In this paper, we develop a successive convex quadratic programming algorithm that generates a sequence of improved points. We prove that the proposed algorithm converges to at least a local optimum of the considered problem. Numerical results confirm the advantages of our proposed algorithm over conventional coordinated precoding approaches where the intercell interference is treated as noise.
Tam, HHM, Tuan, HD, Ngo, DT, Duong, TQ & Poor, HV 2017, 'Joint Load Balancing and Interference Management for Small-Cell Heterogeneous Networks With Limited Backhaul Capacity', IEEE Transactions on Wireless Communications, vol. 16, no. 2, pp. 872-884.
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© 2016 IEEE. In this paper, new strategies are devised for joint load balancing and interference management in the downlink of a heterogeneous network, where small cells are densely deployed within the coverage area of a traditional macrocell. Unlike existing work, the limited backhaul capacity at each base station (BS) is taken into account. Here, users (UEs) cannot be offloaded to any arbitrary BS, but only to ones with sufficient backhaul capacity remaining. Jointly designed with traffic offload, transmit power allocation mitigates the intercell interference to further support the quality of service of each UE. The objective here is either: 1) to maximize the network sum rate subject to minimum throughput requirements at individual UEs, or 2) to maximize the minimum UE throughput. Both formulated problems belong to the difficult class of mixed-integer nonconvex optimization problems. The inherently binary BS-UE association variables are strongly coupled with the transmit power variables, making the problems even more challenging to solve. New iterative algorithms are developed based on an exact penalty method combined with successive convex programming, where the binary BS-UE association problem and the nonconvex power allocation problem are dealt with one at a time. At each iteration of the proposed algorithms, only two simple convex problems need to be solved at the same time scale. It is proven that the algorithms improve the objective functions at each iteration and converge eventually. Numerical results demonstrate the efficiency of the proposed algorithms in both traffic offloading and interference mitigation.
Tawfik, SA, Ali, S, Fronzi, M, Kianinia, M, Tran, TT, Stampfl, C, Aharonovich, I, Toth, M & Ford, MJ 2017, 'First principles investigation of quantum emission from hBN defects', Nanoscale, vol. 9, no. 36, pp. 13575-13582.
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Hexagonal boron nitride (hBN) has recently emerged as a fascinating platformfor room-temperature quantum photonics due to the discovery of robust visiblelight single-photon emitters. In order to utilize these emitters, it isnecessary to have a clear understanding of their atomic structure and theassociated excitation processes that give rise to this single photon emission.Here we perform density-functional theory (DFT) and constrained DFTcalculations for a range of hBN point defects in order to identify potentialemission candidates. By applying a number of criteria on the electronicstructure of the ground state and the atomic structure of the excited states ofthe considered defects, and then calculating the Huang-Rhys (HR) factor, wefind that the CBVN defect, in which a carbon atom substitutes a boron atom andthe opposite nitrogen atom is removed, is a potential emission source with a HRfactor of 1.66, in good agreement with the experimental HR factor. We calculatethe photoluminescence (PL) line shape for this defect and find that itreproduces a number of key features in the the experimental PL lineshape.
Teng, Q, Jin, Y, Li, S, Zhu, J & Guo, Y 2017, 'GFTSM-based Model Predictive Torque Control for PMSM Drive System With Single Phase Current Sensor', Zidonghua Xuebao/Acta Automatica Sinica, vol. 43, no. 9, pp. 1644-1655.
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A global fast terminal sliding mode (GFTSM)-based model predictive torque control (MPTC) strategy is developed for permanent magnet synchronous motor (PMSM) drive system with only one phase current sensor. Generally two phase-current sensors are indispensable for MPTC. In response to only one phase current sensor available and the change of stator resistance, a novel adaptive observer for estimating the remaining two phase currents and time-varying stator resistance is proposed to perform MPTC. Moreover, in view of the variation of system parameters and external disturbance, a new GFTSM-based speed regulator is synthesized to enhance the drive system robustness. In this paper, the GFTSM, based on sliding mode theory, employs the fast terminal sliding mode in both the reaching stage and the sliding stage. The resultant GFTSM-based MPTC PMSM drive system with single phase current sensor has excellent dynamical performance which is very close to the GFTSM-based MPTC PMSM drive system with two-phase current sensors. On the other hand, compared with proportional-integral (PI)-based and sliding mode (SM)-based MPTC PMSM drive systems, it possesses better dynamical response and stronger robustness as well as smaller total harmonic distortion (THD) index of three-phase stator currents in the presence of variation of load torque. The simulation results validate the feasibility and efiectiveness of the proposed scheme.
Tong, X, Ji, Y, Lin, J, Zhu, J, Sun, F, Zhong, Y, Yang, Y & Zhu, X 2017, 'Cooperative spectrum sensing based on a modified shuffled frog leaping algorithm in 5G network', Physical Communication, vol. 25, no. Part 2, pp. 438-444.
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© 2017 Elsevier B.V. The explosion of different types of wireless communications is leading to an impending spectrum famine. As a result, spectrum sensing has gained increasing interest from governments, industry and regulators. In this paper, a novel approach for cooperative spectrum sensing is proposed based on a modified shuffled frog leaping algorithm (SFLA). This approach is to fuse the perceived results of multiple nodes, and to improve the detection reliability. Simulations are used to compare the performance of the modified SFLA to the conventional one. The performance of the proposed cooperative spectrum sensing method based on the modified SFLA and that of the cooperative spectrum sensing method using modified deflection coefficient (MDC) are also compared. Results show that the proposed SFLA outperforms the traditional SFLA, and the proposed cooperative spectrum sensing method based on the modified SFLA gives higher miss detection probability than the MDC-based method, which validates the effectiveness of the modified SFLA-based cooperative sensing method.
Tong, X, Yang, Y, Zhong, Y, Zhu, X, Lin, J & Dutkiewicz, E 2017, 'Design of an On-Chip Highly Sensitive Misalignment Sensor in Silicon Technology', IEEE Sensors Journal, vol. 17, no. 5, pp. 1211-1212.
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© 2016 IEEE. Advanced micromachining technology has made magnificent progress for fabrication of non-planar circuits. Using this technology, circuits and systems can be implemented in a more cost-effective way. Unlike the conventional planar circuit, low-cost and highly sensitive misalignment sensor is required to detect imperfect placement of different micro-devices, which may be of the order of sub-micrometers. Currently, this is hardly to be achieved by using the existing approaches. In this letter, we present a novel sensor design approach utilizing the parasitic capacitance of an integrated coupled-line resonator for misalignment sensing. Due to vertical misalignment between two metal strips, the parasitic capacitance of the sensor varies, which results in a resonance shift from 53 to 68 GHz, while a reasonably strong transmission notch is still maintained. Taking advantage of this principle, misalignment can be effectively detected. To prove the concept, several devices are fabricated in a standard silicon technology. Three samples with the same structure are used to evaluate the reliability, while eight different structures are used to verify the concept. All results are extensively validated through both simulation and measurements.
Tran, TT, Choi, S, Scott, JA, Xu, Z, Zheng, C, Seniutinas, G, Bendavid, A, Fuhrer, MS, Toth, M & Aharonovich, I 2017, 'Room‐Temperature Single‐Photon Emission from Oxidized Tungsten Disulfide Multilayers', Advanced Optical Materials, vol. 5, no. 5, pp. 1600939-1600939.
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Robust quantum emitters fabricated by thermal oxidation of tungsten disulfide multilayers are reported. The emitters show robust, optically stable, linearly polarized luminescence at room temperature, can be modeled using a three‐level system, and exhibit moderate bunching. Overall, the results provide important insights into understanding of defect formation and quantum emitter activation in two‐dimensional materials.
Tran, TT, Kianinia, M, Bray, K, Kim, S, Xu, Z-Q, Gentle, A, Sontheimer, B, Bradac, C & Aharonovich, I 2017, 'Nanodiamonds with photostable, sub-gigahertz linewidths quantum emitters', APL Photonics, vol. 2, no. 11, pp. 116103-116103.
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Single photon emitters with narrow linewidths are highly sought after forapplications in quantum information processing and quantum communications. Inthis letter, we report on a bright, highly polarized near infrared singlephoton emitter embedded in diamond nanocrystals with a narrow, sub GHz opticallinewidths at 10K. The observed zero phonon line at ~ 780 nm is opticallystable under low power resonant excitation and blue shifts as the excitationpower increases. Our results highlight the prospect for using new near infraredcolor centers in nanodiamonds for quantum applications.
Tran, TT, Kianinia, M, Nguyen, M, Kim, S, Xu, Z-Q, Kubanek, A, Toth, M & Aharonovich, I 2017, 'Resonant Excitation of Quantum Emitters in Hexagonal Boron Nitride', ACS Photonics, vol. 5, no. 2, pp. 295-300.
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Quantum emitters in layered hexagonal boron nitride (hBN) have recentlyattracted a great attention as promising single photon sources. In this work,we demonstrate resonant excitation of a single defect center in hBN, one of themost important prerequisites for employment of optical sources in quantuminformation application. We observe spectral linewidths of hBN emitter narrowerthan 1 GHz while the emitter experiences spectral diffusion. Temporalphotoluminescence measurements reveals an average spectral diffusion time ofaround 100 ms. On-resonance photon antibunching measurement is also realized.Our results shed light on the potential use of quantum emitters from hBN innanophotonics and quantum information.
Tran, TT, Wang, D, Xu, Z-Q, Yang, A, Toth, M, Odom, TW & Aharonovich, I 2017, 'Deterministic Coupling of Quantum Emitters in 2D Materials to Plasmonic Nanocavity Arrays', Nano Letters, vol. 17, no. 4, pp. 2634-2639.
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© 2017 American Chemical Society. Quantum emitters in two-dimensional materials are promising candidates for studies of light-matter interaction and next generation, integrated on-chip quantum nanophotonics. However, the realization of integrated nanophotonic systems requires the coupling of emitters to optical cavities and resonators. In this work, we demonstrate hybrid systems in which quantum emitters in 2D hexagonal boron nitride (hBN) are deterministically coupled to high-quality plasmonic nanocavity arrays. The plasmonic nanoparticle arrays offer a high-quality, low-loss cavity in the same spectral range as the quantum emitters in hBN. The coupled emitters exhibit enhanced emission rates and reduced fluorescence lifetimes, consistent with Purcell enhancement in the weak coupling regime. Our results provide the foundation for a versatile approach for achieving scalable, integrated hybrid systems based on low-loss plasmonic nanoparticle arrays and 2D materials.
Tuan, HD, Ngo, DT & Tam, HHM 2017, 'Joint power allocation for MIMO-OFDM full-duplex relaying communications', EURASIP Journal on Wireless Communications and Networking, vol. 2017, no. 1, pp. 1-17.
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© 2017, The Author(s). In this paper, we address the problem of joint power allocation in a two-hop MIMO-OFDM network, where two full-duplex users communicate with each other via an amplify-and-forward relay. We consider a general model in which the full-duplex relay can forward the received message in either one-way or two-way mode. Our aim is to maximize the instantaneous end-to-end total throughput, subject to (i) the separate sum-power constraints at individual nodes or (ii) the joint sum-power constraint of the whole network. The formulated problems are large-scale nonconvex optimization problems, for which efficient and optimal solutions are currently not available. Using the successive convex approximation approach, we develop novel iterative algorithms of extremely low complexity which are especially suitable for large-scale computation. In each iteration, a simple closed-form solution is derived for the approximated convex program. The proposed algorithms guarantee to converge to at least a local optimum of the nonconvex problems. Numerical results verify that the devised solutions converge quickly, and that our optimal power allocation schemes significantly improve the throughput of MIMO-OFDM full-duplex one-way/two-way relaying over the conventional half-duplex relaying strategy.
Tuan, HD, Tam, HHM, Nguyen, HH, Duong, TQ & Poor, HV 2017, 'Superposition Signaling in Broadcast Interference Networks', IEEE Transactions on Communications, vol. 65, no. 11, pp. 4646-4656.
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© 1972-2012 IEEE. It is known that superposition signaling in Gaussian interference networks is capable of improving the achievable rate region. However, the problem of maximizing the rate gain offered by superposition signaling is computationally prohibitive, even in the simplest case of two-user single-input single-output interference networks. This paper examines superposition signaling for the general multiple-input multiple-output broadcast Gaussian interference networks. The problem of maximizing either the sum rate or the minimal user's rate under superposition signaling and dirty paper coding is solved by a computationally efficient path-following procedure, which requires only a convex quadratic program for each iteration but ensures convergence at least to a locally optimal solution. Numerical results demonstrate the substantial performance advantage of the proposed approach.
Tuyen Le, A, Tran, LC & Huang, X 2017, 'Cyclostationary Analysis of Analog Least Mean Square Loop for Self-Interference Cancellation in In-Band Full-Duplex Systems', IEEE Communications Letters, vol. 21, no. 12, pp. 2738-2741.
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© 2017 IEEE. Analog least mean square (ALMS) loop is a promising mechanism to suppress self-interference (SI) in an in-band full-duplex (IBFD) system. In this letter, a general solution for the weighting error function is derived to investigate the performance of the ALMS loop employed in any IBFD system. The solution is then applied to IBFD systems with single carrier and multicarrier signaling. Due to the cyclostationary property of the transmitted signal, the weighting error function in the multicarrier system varies more significantly than in the single carrier. Therefore, if the ALMS loop can perfectly mimic the SI channel, SI in the single carrier system can be suppressed to a much smaller level than that in the multi-carrier counterpart.
Unanue, IJ, Borzeshi, EZ & Piccardi, M 2017, 'Recurrent neural networks with specialized word embeddings for health-domain named-entity recognition', Journal of Biomedical Informatics, vol. 76, no. December 2017, pp. 102-109.
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Background. Previous state-of-the-art systems on Drug Name Recognition (DNR)and Clinical Concept Extraction (CCE) have focused on a combination of text'feature engineering' and conventional machine learning algorithms such asconditional random fields and support vector machines. However, developing goodfeatures is inherently heavily time-consuming. Conversely, more modern machinelearning approaches such as recurrent neural networks (RNNs) have provedcapable of automatically learning effective features from either randomassignments or automated word 'embeddings'. Objectives. (i) To create a highlyaccurate DNR and CCE system that avoids conventional, time-consuming featureengineering. (ii) To create richer, more specialized word embeddings by usinghealth domain datasets such as MIMIC-III. (iii) To evaluate our systems overthree contemporary datasets. Methods. Two deep learning methods, namely theBidirectional LSTM and the Bidirectional LSTM-CRF, are evaluated. A CRF modelis set as the baseline to compare the deep learning systems to a traditionalmachine learning approach. The same features are used for all the models.Results. We have obtained the best results with the Bidirectional LSTM-CRFmodel, which has outperformed all previously proposed systems. The specializedembeddings have helped to cover unusual words in DDI-DrugBank and DDI-MedLine,but not in the 2010 i2b2/VA IRB Revision dataset. Conclusion. We present astate-of-the-art system for DNR and CCE. Automated word embeddings has allowedus to avoid costly feature engineering and achieve higher accuracy.Nevertheless, the embeddings need to be retrained over datasets that areadequate for the domain, in order to adequately cover the domain-specificvocabulary.
Walsh, L, Bluff, A & Johnston, A 2017, 'Water, image, gesture and sound: composing and performing an interactive audiovisual work', Digital Creativity, vol. 28, no. 3, pp. 177-195.
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© 2017 Informa UK Limited, trading as Taylor & Francis Group. Performing and composing for interactive audiovisual system presents many challenges to the performer. Working with visual, sonic and gestural components requires new skills and new ways of thinking about performance. However, there are few studies that focus on performer experience with interactive systems. We present the work Blue Space for oboe and interactive audiovisual system, highlighting the evolving process of the collaborative development of the work. We consider how musical and technical demands interact in this process, and outline the challenges of performing with interactive systems. Using the development of Blue Space as a self-reflective case study, we examine the role of gestures in interactive audiovisual works and identify new modes of performance.
Wang, AY, Zhu, JG & Shang, YQ 2017, 'Optimization ofiron core design for permanent-magnet synchronous machines with three-segment Halbach magnet array', Dianji yu Kongzhi Xuebao/Electric Machines and Control, vol. 21, no. 4, pp. 37-43.
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Halbach magnet array and concentrated fractional-slot winding can enhance the output torque, and reduce the ripple torque of permanent magnet synchronous machines (PMSMs) to meet the demands of servo system for rapid response and high precision. However, the iron core needs to be redesigned. By the theory of Halbach, it established a PMSM model with three-segment Halbach magnet array, and analyzed the characteristics of air gap magnetic field to reduce the effects of the harmonic air-gap field and harmonic slot electromotive torque. The structural characteristics of the motor core were analyzed, and multiple critical dimensions for design variables were determined. A double layer optimization model was developed to maximize the electromagnetic torque and minimize the torque ripples. The finite element method was employed to calculate the magnetic field and the Taguchi method to simplify the design process. Finally, a multi-variable and multi-objective optimization process was implemented for design optimization of a servo motor with eight-poles and nine-slots.
Wang, C, Ni, W, Sun, X, Wang, L, Wang, C & Jin, K 2017, 'Relaxor‐like behaviors in Na1/2Bi1/2Cu3Ti4O12 ceramics', Journal of the American Ceramic Society, vol. 100, no. 5, pp. 2016-2023.
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AbstractDielectric properties of Na1/2Bi1/2Cu3Ti4O12 ceramics were evaluated over the temperature range 300‐720 K. Two relaxor‐like dielectric anomalies were found. The low‐temperature anomaly was confirmed to be an oxygen‐vacancy‐related relaxation process. It is a pseudo‐relaxor behavior caused by a bulk relaxation and a Maxwell‐Wagner relaxation. The high‐temperature one was evidenced to be an electric ferroelectric phase‐transition process resulting from the oxygen‐vacancy ordering.
Wang, H, Nguyen, DN, Dutkiewicz, E, Fang, G & Mueck, MD 2017, 'Negotiable Auction Based on Mixed Graph: A Novel Spectrum Sharing Framework', IEEE Transactions on Cognitive Communications and Networking, vol. 3, no. 3, pp. 390-403.
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© 2015 IEEE. Auction-based spectrum sharing is a promising solution to improve the spectrum utilization in 5G networks. Along with the spatial reuse, we observe that the ability to adjust the coverage of a spectrum bidder can provide room to itself for further negotiation while auctioning. In this paper, we propose a novel economic tool, size-negotiable auction mechanism (SNAM), which provides a hybrid solution between auction and negotiation for multi-buyers sharing spectrum chunks from a common database. Unlike existing auction-based spectrum sharing models, each bidder of the SNAM submits its bid for using the spectrum per unit space and a set of coverage ranges over which the bidder is willing to pay for the spectrum. The auctioneer then coordinates the interference areas (or coverage negotiation) to ensure no two winners interfere with each other while aiming to maximize the auction's total coverage area or revenue. In this scenario, the undirected graph used by existing auction mechanisms fails to model the interference among bidders. Instead, we construct a mixed interference graph and prove that SNAM's auctioning on the mixed graph is truthful and individually rational. Simulation results show that, compared with existing auction approaches, the proposed SNAM dramatically improves the spatial efficiency, hence leads to significantly higher seller revenue and buyer satisfaction under various setups. Thanks to its low complexity and low overhead, SNAM can target fine timescale trading (in minutes or hours) with a large number of bidders and requested coverages.
WANG, L, GUO, Y, ZHANG, Q & YUE, T 2017, 'Suggestion for aircraft flying qualities requirements of a short-range air combat mission', Chinese Journal of Aeronautics, vol. 30, no. 3, pp. 881-897.
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Wang, R, Thakur, CS, Cohen, G, Hamilton, TJ, Tapson, J & van Schaik, A 2017, 'Neuromorphic Hardware Architecture Using the Neural Engineering Framework for Pattern Recognition', IEEE Transactions on Biomedical Circuits and Systems, vol. 11, no. 3, pp. 574-584.
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© 2007-2012 IEEE. We present a hardware architecture that uses the neural engineering framework (NEF) to implement large-scale neural networks on field programmable gate arrays (FPGAS) for performing massively parallel real-time pattern recognition. NEF is a framework that is capable of synthesising large-scale cognitive systems from subnetworks and we have previously presented an FPGA implementation of the NEF that successfully performs nonlinear mathematical computations. That work was developed based on a compact digital neural core, which consists of 64 neurons that are instantiated by a single physical neuron using a time-multiplexing approach. We have now scaled this approach up to build a pattern recognition system by combining identical neural cores together. As a proof of concept, we have developed a handwritten digit recognition system using the MNIST database and achieved a recognition rate of 96.55%. The system is implemented on a state-of-the-art FPGA and can process 5.12 million digits per second. The architecture and hardware optimisations presented offer high-speed and resource-efficient means for performing high-speed, neuromorphic, and massively parallel pattern recognition and classification tasks.
Wang, T, Liu, C, Lei, G, Guo, Y & Zhu, J 2017, 'Model predictive direct torque control of permanent magnet synchronous motors with extended set of voltage space vectors', IET Electric Power Applications, vol. 11, no. 8, pp. 1376-1382.
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© The Institution of Engineering and Technology. The finite-control-set model predictive direct torque control (FCS-MPDTC) is a novel control scheme for permanent magnet synchronous motors (PMSMs). A key feature of FCS-MPDTC is that the eight possible voltage space vectors or switching combinations of the power converters are directly taken into account as the control input of the system. A cost function is used in FCS-MPDTC to evaluate each possible voltage space vector and the one with minimum cost is applied to the power converter. Due to the considerable torque and flux ripples, to improve the performance of FCS-MPDTC, this study presents an extended set of 20 modulated voltage space vectors with fixed duty ratio. For further improvement, a larger set size can be chosen, but this requires a larger computing power. To mitigate the computational burden caused by increased number of voltage space vectors, a pre-selective scheme is designed for the proposed FCS-MPDTC to filter out the impractical voltage vectors instead of evaluating all 20 voltage space vectors. The drive system efficiencies of conventional direct torque control, conventional FCS-MPDTC and proposed method are investigated. The theory and simulation are validated by experimental results on a PMSM prototype.
Wang, T, Liu, C, Xu, W, Lei, G, Jafari, M, Guo, Y & Zhu, J 2017, 'Fabrication and Experimental Analysis of an Axially Laminated Flux-Switching Permanent-Magnet Machine', IEEE Transactions on Industrial Electronics, vol. 64, no. 2, pp. 1081-1091.
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© 1982-2012 IEEE. The traditional flux-switching permanent-magnet machines (FSPMMs) with radial lamination have serious partial magnetic saturation for their nonlinear magnetic path, where the maximal flux density is usually more than 2.0 T occurring at the edges/tips of stator teeth or rotor poles. In this case, the core loss of FSPMMs becomes evident especially beyond the rated speed, which leads to decrease of output power, torque/power density, and efficiency. To overcome these problems, an axially laminated flux-switching permanent-magnet machine (ALFSPMM) with high grain-oriented silicon steel stator and rotor cores is proposed. The detailed fabrication procedures are presented in this paper. The theoretical characteristics of the ALFSPMM, such as back electromotive force, self-/mutual inductance, and cogging torque are calculated by the two-dimensional finite-element method (FEM). The influence of misalignment between the stator core and the rotor shaft (a common issue in motor manufacturing) is investigated by the FEM. Experimental measurements of the prototype machine are presented to validate the FEM calculation. In addition, a simple low-cost method to measure the cogging torque is also presented in this paper.
Wang, TQ, Li, H & Huang, X 2017, 'Diversity Combining for Layered Asymmetrically Clipped Optical OFDM Using Soft Successive Interference Cancellation', IEEE Communications Letters, vol. 21, no. 6, pp. 1309-1312.
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© 1997-2012 IEEE. In this letter, we present a novel diversity combining receiver for demodulating layered asymmetrically clipped optical orthogonal frequency division multiplexing. The receiver consists of a soft successive interference cancellation (SIC) module which cancels the inter-layer interference (ILI) using the minimum mean square error (MMSE) estimates of the information symbols, and a diversity combining module which extracts the diversity components from the clipping noise. We show that the soft SIC module alone can effectively suppress the ILI, leading to bit error rates (BERs) resembling those of a genie receiver which is free of error propagation. It is also shown that the diversity combining receiver which combines the MMSE estimates with their diversity components outperforms the genie receiver by up to 2 dB at the BER of 10-6.
Wang, X, Cheng, E, Burnett, IS, Huang, Y & Wlodkowic, D 2017, 'Automatic multiple zebrafish larvae tracking in unconstrained microscopic video conditions', Scientific Reports, vol. 7, no. 1, pp. 1-8.
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AbstractThe accurate tracking of zebrafish larvae movement is fundamental to research in many biomedical, pharmaceutical, and behavioral science applications. However, the locomotive characteristics of zebrafish larvae are significantly different from adult zebrafish, where existing adult zebrafish tracking systems cannot reliably track zebrafish larvae. Further, the far smaller size differentiation between larvae and the container render the detection of water impurities inevitable, which further affects the tracking of zebrafish larvae or require very strict video imaging conditions that typically result in unreliable tracking results for realistic experimental conditions. This paper investigates the adaptation of advanced computer vision segmentation techniques and multiple object tracking algorithms to develop an accurate, efficient and reliable multiple zebrafish larvae tracking system. The proposed system has been tested on a set of single and multiple adult and larvae zebrafish videos in a wide variety of (complex) video conditions, including shadowing, labels, water bubbles and background artifacts. Compared with existing state-of-the-art and commercial multiple organism tracking systems, the proposed system improves the tracking accuracy by up to 31.57% in unconstrained video imaging conditions. To facilitate the evaluation on zebrafish segmentation and tracking research, a dataset with annotated ground truth is also presented. The software is also publicly accessible.
Wong, S-W, Deng, F, Wu, Y-M, Lin, J-Y, Zhu, L, Chu, Q-X & Yang, Y 2017, 'Individually Frequency Tunable Dual- and Triple-band Filters in a Single Cavity', IEEE Access, vol. 5, pp. 11615-11625.
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© 2013 IEEE. This paper presents a new class of second-order individually and continuously tunable dual- and triple-band bandpass filters in a single metal cavity. Each passband is realized by two identical metal posts. These dual- and triple-band tunable filters are achieved by putting two or three identical sets of metal-post pair in a single metal cavity. Metal screws are co-designed as a part of the metal posts to control their insertion depth inside the cavity. In this way, the resonant frequencies can be continuously controlled and designed at the desired frequency bands. Moreover, the distance between the two metal posts in a post pair can be freely tuned. Thus, the external quality factor (Qe) and coupling coefficient (k) between the adjacent modes can be easily adjusted to meet the specified requirement in synthesis design. At the bottom of the cavity, some grooves are used to extend the tunable frequency range and make the resonant frequency linearly varied with the height of the metal post. The center frequency of each passband can be independently tuned with a frequency range of 0.8-3.2 GHz and tunable ratio of 4. Finally, the continuously tunable dual- and triple-band bandpass filters prototypes with second order response are designed and fabricated, of which each passband can be individually tuned with a large tuning range.
Wu, G, Liu, RP, Ni, W, Sutton, GJ & Xu, P 2017, 'Modeling Channel Switching and Contention Control in Vehicular Networks', IEEE Access, vol. 5, pp. 23102-23110.
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© 2017 IEEE. In vehicular networks, multi-channel operation standard IEEE 1609.4 is designed for vehicular communications across multiple channels. It has been revealed that such multi-channel operations may result in high contention in vehicular communications. However, existing analytical models are unable to capture the dynamic characteristic during channel switching. We develop a novel Markov model that takes into account the dynamic contention behavior during channel switching. In particular, our model reveals the high contention caused by the burst arrivals, which are the results of multi-channel operations. To combat such performance decline, we propose two solutions, a centralized equal-spaced algorithm and a distributed random-spaced algorithm. The key idea is to disperse the burst packet arrivals across the available timeframe in order to alleviate contention. Our model, validated by simulations, accurately characterizes the high contention caused by multi-channel operations. Our results demonstrate our proposed solutions can effectively mitigate packet collision, enhance reliability, and improve system throughput during the multi-channel operations.
Xiao, F, Dong, L, Li, L & Liao, X 2017, 'A Frequency-Fixed SOGI-Based PLL for Single-Phase Grid-Connected Converters', IEEE Transactions on Power Electronics, vol. 32, no. 3, pp. 1713-1719.
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© 1986-2012 IEEE. Second-order generalized integrator (SOGI) based phase-locked loops (PLLs) are widely used for grid synchronization in single-phase grid-connected power converters. Previously, the estimated frequency of the PLL stage is fed back to the front-end SOGI block to make SOGI-PLLs frequency-Adaptive, which increases the implementation complexity, and makes the tuning sensitive, thus reducing stability margins. Alternatively, a frequency-fixed SOGI-based PLL (briefly called FFSOGI-PLL) is proposed to ensure stability and simple implementation in this letter. It is commonly known that the in-phase and quadrature-phase signals generated by the frequency-fixed SOGI are of different amplitudes in the presence of frequency drifts, which causes second-harmonic ripples in the estimated parameters of the PLL loop. To deal with this issue, a simple yet effective method is developed in FFSOGI-PLL. The standard SOGI-PLL is first introduced, followed by the working principle and small-signal model of FFSOGI-PLL. The FFSOGI-PLL is then compared with the SOGI-PLL in terms of stability and transient performance. Finally, experimental results are presented to demonstrate the effectiveness of FFSOGI-PLL.
Xiao, F, Dong, L, Li, L & Liao, X 2017, 'A Novel Open-Loop Frequency Estimation Method for Single-Phase Grid Synchronization Under Distorted Conditions', IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 5, no. 3, pp. 1287-1297.
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© 2013 IEEE. In this paper, a new open-loop architecture with good dynamic performance and strong harmonic rejection capability is proposed for single-phase grid synchronization under distorted conditions. Different from previous single-phase grid synchronization algorithms based on the phase-locked loop technique, the proposed method is to estimate the frequency and phase angle of the grid voltage in an open-loop manner so that fast dynamic response and enhanced system stability can be achieved. First, an open-loop frequency estimation algorithm is introduced under ideal grid condition. Then, it is extended to distorted grid voltages through the combination of the developed frequency estimation unit and a prefiltering stage consisting of a second-order low-pass filter and a cascaded delayed signal cancellation (DSC) module. In addition, a transient process smoothing unit is designed to achieve smooth frequency transients in cases where the grid voltage experiences fast and large changes. The working principle of the new frequency estimation algorithm and the developed single-phase grid synchronization approach is given in detail, together with some simulation and experiment results for verifying their performance.
Xiao, F, Dong, L, Li, L & Liao, X 2017, 'Fast voltage detection method for grid‐tied renewable energy generation systems under distorted grid voltage conditions', IET Power Electronics, vol. 10, no. 12, pp. 1487-1493.
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© The Institution of Engineering and Technology. A fast voltage detection method to assist with the low-voltage ride-through operation of grid-tied renewable energy generation systems is proposed in this study. It is designed to detect every phase voltage, so that it can be applied in both three-phase and single-phase applications. The whole voltage detection approach consists of two stages, the pre-filtering stage and the voltage detection stage. In the pre-filtering stage, a cascaded delayed signal cancellation (CDSC) module and a low-pass filter are connected in series to filter low-order harmonics and high-frequency noises. For eliminating the low-order harmonics of interest, different types of CDSC methods are studied in detail. Subsequently, a new orthogonal signal generator is built to calculate the voltage amplitude in the voltage detection stage. Finally, the proposed voltage detection method is verified by experimental results.
Xu, W, Duan, N, Wang, S, Guo, Y & Zhu, J 2017, 'Modeling and Measurement of Magnetic Hysteresis of Soft Magnetic Composite Materials Under Different Magnetizations', IEEE Transactions on Industrial Electronics, vol. 64, no. 3, pp. 2459-2467.
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© 1982-2012 IEEE. The soft magnetic composite (SMC) materials and their application in electromagnetic devices have undergone significant development due to their unique advantages, such as low eddy-current loss, quasi-isotropy of mechanical and magnetic properties, low cost, and low material consumption during the production process. However, the magnetic properties of the SMC materials are very different from that of the laminated SiFe materials, which are particularly challenging for the design and application of electrical machines. This paper presents the modeling and measurement of magnetic properties of the SMC materials under both alternating and rotational magnetic excitations. Based on the underlying magnetization mechanisms, a vectorial elemental operator with biaxial anisotropy is introduced, and the concept of distribution function is utilized to describe the density of operators in the specimen. To verify this proposed model, the magnetic hysteresis of the SMC material is simulated and compared with the experimental results obtained by the three-dimensional magnetic property measurement system. The good agreement shows the validity and practicability of this vectorial elemental operator.
Xu, Y, Wu, C, Zheng, K, Wang, X, Niu, X & Lu, T 2017, 'Computing Adaptive Feature Weights with PSO to Improve Android Malware Detection', Security and Communication Networks, vol. 2017, pp. 1-14.
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Android malware detection is a complex and crucial issue. In this paper, we propose a malware detection model using a support vector machine (SVM) method based on feature weights that are computed by information gain (IG) and particle swarm optimization (PSO) algorithms. The IG weights are evaluated based on the relevance between features and class labels, and the PSO weights are adaptively calculated to result in the best fitness (the performance of the SVM classification model). Moreover, to overcome the defects of basic PSO, we propose a new adaptive inertia weight method called fitness-based and chaotic adaptive inertia weight-PSO (FCAIW-PSO) that improves on basic PSO and is based on the fitness and a chaotic term. The goal is to assign suitable weights to the features to ensure the best Android malware detection performance. The results of experiments indicate that the IG weights and PSO weights both improve the performance of SVM and that the performance of the PSO weights is better than that of the IG weights.
Xu, Z, Yan, J, Xu, RY & Mei, L 2017, 'Guest Editorial: Visual Multimedia Learning from Big Surveillance Data', Multimedia Tools and Applications, vol. 76, no. 13, pp. 14557-14557.
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Xu, Z-Q, Elbadawi, C, Tran, TT, Kianinia, M, Li, X, Liu, D, Hoffman, TB, Nguyen, M, Kim, S, Edgar, JH, Wu, X, Song, L, Ali, S, Ford, M, Toth, M & Aharonovich, I 2017, 'Single Photon Emission from Plasma Treated 2D Hexagonal Boron Nitride', Nanoscale, vol. 10, no. 17, pp. 7957-7965.
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Artificial atomic systems in solids are becoming increasingly importantbuilding blocks in quantum information processing and scalable quantumnanophotonic networks. Yet, synthesis of color centers that act as singlephoton emitters which are suitable for on-chip applications is still beyondreach. Here, we report a number of plasma and thermal annealing methods for thefabrication of emitters in tape-exfoliated hexagonal boron nitride (hBN)crystals. A two-step process comprised of Ar plasma etching and subsequentannealing in Ar is highly robust, and yields a seven-fold increase in theconcentration of emitters in hBN. The initial plasma etching step generatesemitters that suffer from blinking and bleaching, whereas the two-step processyields emitters that are photostable at room temperature and have an emissionenergy distribution that is red-shifted relative to that of pristine hBN. Ananalysis of emitters fabricated by a range of plasma and annealing treatments,combined with a theoretical investigation of point defects in hBN indicatesthat single photon emitters characterized by a high degree of photostabilityand emission wavelengths greater than ~700 nm are associated with defectcomplexes that contain oxygen. This is further confirmed by generating theemitters by annealing hBN in an oxidative atmosphere. Our findings advancepresent understanding of the structure of quantum emitter in hBN and enhancethe nanofabrication toolkit that is needed to realize integrated quantumnanophotonics based on 2D materials.
Xuan, J, Lu, J, Zhang, G, Xu, RYD & Luo, X 2017, 'A Bayesian nonparametric model for multi-label learning', Machine Learning, vol. 106, no. 11, pp. 1787-1815.
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© 2017, The Author(s). Multi-label learning has become a significant learning paradigm in the past few years due to its broad application scenarios and the ever-increasing number of techniques developed by researchers in this area. Among existing state-of-the-art works, generative statistical models are characterized by their good generalization ability and robustness on large number of labels through learning a low-dimensional label embedding. However, one issue of this branch of models is that the number of dimensions needs to be fixed in advance, which is difficult and inappropriate in many real-world settings. In this paper, we propose a Bayesian nonparametric model to resolve this issue. More specifically, we extend a Gamma-negative binomial process to three levels in order to capture the label-instance-feature structure. Furthermore, a mixing strategy for Gamma processes is designed to account for the multiple labels of an instance. The mixed process also leads to a difficulty in model inference, so an efficient Gibbs sampling inference algorithm is then developed to resolve this difficulty. Experiments on several real-world datasets show the performance of the proposed model on multi-label learning tasks, comparing with three state-of-the-art models from the literature.
Xuan, J, Lu, J, Zhang, G, Xu, RYD & Luo, X 2017, 'Bayesian Nonparametric Relational Topic Model through Dependent Gamma Processes', IEEE Transactions on Knowledge and Data Engineering, vol. 29, no. 7, pp. 1357-1369.
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© 2016 IEEE. Traditional relational topic models provide a successful way to discover the hidden topics from a document network. Many theoretical and practical tasks, such as dimensional reduction, document clustering, and link prediction, could benefit from this revealed knowledge. However, existing relational topic models are based on an assumption that the number of hidden topics is known a priori, which is impractical in many real-world applications. Therefore, in order to relax this assumption, we propose a nonparametric relational topic model using stochastic processes instead of fixed-dimensional probability distributions in this paper. Specifically, each document is assigned a Gamma process, which represents the topic interest of this document. Although this method provides an elegant solution, it brings additional challenges when mathematically modeling the inherent network structure of typical document network, i.e., two spatially closer documents tend to have more similar topics. Furthermore, we require that the topics are shared by all the documents. In order to resolve these challenges, we use a subsampling strategy to assign each document a different Gamma process from the global Gamma process, and the subsampling probabilities of documents are assigned with a Markov Random Field constraint that inherits the document network structure. Through the designed posterior inference algorithm, we can discover the hidden topics and its number simultaneously. Experimental results on both synthetic and real-world network datasets demonstrate the capabilities of learning the hidden topics and, more importantly, the number of topics.
Yang, J, Jin, X, Wu, X, Acuna, P, Aguilera, RP, Morstyn, T & Agelidis, VG 2017, 'Decentralised control method for DC microgrids with improved current sharing accuracy', IET Generation, Transmission & Distribution, vol. 11, no. 3, pp. 696-706.
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Yang, T, Yang, L, Guo, YJ & Yuan, J 2017, 'A Non-Orthogonal Multiple-Access Scheme Using Reliable Physical-Layer Network Coding and Cascade-Computation Decoding', IEEE Transactions on Wireless Communications, vol. 16, no. 3, pp. 1633-1645.
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© 2017 IEEE. This paper studies non-orthogonal transmission over a K -user fading multiple access channel. We propose a new reliable physical-layer network coding and cascade-computation decoding scheme. In the proposed scheme, K single-antenna users encode their messages by the same practical channel code and QAM modulation, and transmit simultaneously. The receiver chooses K linear coefficient vectors and computes the associated K layers of finite-field linear message combinations in a cascade manner. Finally, the K users' messages are recovered by solving the K linear equations. The proposed can be regarded as a generalized onion peeling. We study the optimal network coding coefficient vectors used in the cascade computation. Numerical results show the performance of the proposed approaches that of the iterative maximum a posteriori probability detection and decoding scheme, but without using receiver iteration. This results in considerable complexity reduction, processing delay, and easier implementation. Our proposed scheme significantly outperforms the iterative detection and decoding scheme with a single iteration, for example, by 1.7 dB for the two user case. The proposed scheme provides a competitive solution for non-orthogonal multiple access.
Yang, Y, Liu, H, Hou, ZJ, Zhu, X, Dutkiewicz, E & Xue, Q 2017, 'Compact On-Chip Bandpass Filter With Improved In-Band Flatness and Stopband Attenuation in 0.13- $\mu \text{m}$ (Bi)-CMOS Technology', IEEE Electron Device Letters, vol. 38, no. 10, pp. 1359-1362.
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© 1980-2012 IEEE. In this letter, an on-chip miniaturized bandpass filter (BPF) is presented, which is based on a grounded center-Tapped ring resonator (CTRR) with shunt capacitive loading. To analyze the principle of this design, a simple but effective equivalent circuit model is provided. Using this model, it is easy to show that the CTRR-based approach has a potential to generate two transmission poles within the passband. Compared with the conventional single-pole-based approach, this dual-pole design not only possesses a flexibility of controlling the passband width, but also has better flatness of insertion loss in the passband. In addition, this approach is able to significantly improve the stopband performance. To further demonstrate the feasibility of this approach in practice, the structure is implemented and fabricated in a commercial 0.13-μ (Bi)-CMOS SiGe technology. The measured results show that the BPF has a center frequency at 33 GHz with a bandwidth of 42.4%. The minimum insertion loss is 2.6 dB, while the stopband rejection is maintained to be better than 20 dB beyond 58 GHz. The chip, excluding the pads, is very compact at only 0.03 mm2 (0.11 × 0.28 mm2.
Yang, Y, Simorangkir, RBVB, Zhu, X, Esselle, K & Xue, Q 2017, 'A Novel Boresight and Conical Pattern Reconfigurable Antenna With the Diversity of 360° Polarization Scanning', IEEE Transactions on Antennas and Propagation, vol. 65, no. 11, pp. 5747-5756.
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© 1963-2012 IEEE. A novel design of boresight and conical pattern reconfigurable antenna with the capability of 360° polarization scanning is presented in this paper. At boresight mode, the antenna produces a continuously reconfigurable polarization over 360° in the azimuth plane, which provides adaptive-polarization reception between a transmitter and a receiver. The antenna is analyzed in terms of the electric field with an explanation of the generation of TM11 and TM02 resonant modes, which provides an innovative method of designing pattern reconfigurable antennas for the WLAN applications. The proposed method is validated by a good agreement between simulation and experimental results for an antenna designed to provide boresight and conical pattern switching at 2.4 GHz. The gain of 6.05 dBi and efficiency of 86.7% are measured in the boresight mode, corresponding to 4.39 dBi and 82.4% at conical mode.
Yang, Y, Zhu, X, Dutkiewicz, E & Xue, Q 2017, 'Design of a Miniaturized On-Chip Bandpass Filter Using Edge-Coupled Resonators for Millimeter-Wave Applications', IEEE Transactions on Electron Devices, vol. 64, no. 9, pp. 3822-3828.
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© 2017 IEEE. A unique miniaturization technique for on-chip passive device implemented in gallium arsenide (GaAs)-based technology is presented, which is based on edge-coupled cells (ECCs). The principle of an ECC is first studied by means of the equivalent LC circuits. Then, using the ECC as a baseline, a combination of different shorting-ground and tapping methods is fully investigated in terms of their impact on frequency responses. By directly shorting the specific edge-coupled fingers to the ground, an ECC can be converted into a resonator without increasing any physical size. To further demonstrate the feasibility of using this technique for miniaturized monolithic microwave integrated circuit design, an on-chip bandpass filter (BPF) is implemented and fabricated in a commercial 0.1-μ m GaAs technology. The measurement results show that the 3-dB bandwidth of the filter is from 21.2 to 26.5 GHz, while the insertion loss is less than 2.9 dB at 23 GHz. In addition, more than 30 dB of suppression is achieved from 0 to 15 GHz and from 44 to 54 GHz. The size of the BPF is only 640 × 280 μ m2, excluding the pads, which is equivalent to 0.17 × 0.08 λg2. (λg is the guided wavelength at 23.5 GHz.)
Ye, L, Argha, A, Celler, BG, Nguyen, HT & Su, SW 2017, 'Online auto-calibration of triaxial accelerometer with time-variant model structures', Sensors and Actuators A: Physical, vol. 266, pp. 294-307.
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© 2017 Elsevier B.V. In this paper, an online auto-calibration method for MicroElectroMechanical Systems (MEMS) triaxial accelerometer (TA) is proposed, which can simultaneously identify the time-dependent model structure and its parameters during the changes of the operating environment. Firstly, the model as well as its associated cost function is linearized by a new proposed linearization approach. Then, exploiting an online sparse recursive least square (SPARLS) estimation, the unknown parameters are identified. In particular, the online sparse recursive method is based on an L1-norm penalized expectation-maximum (EM) algorithm, which can amend the model automatically by penalizing the insignificant parameters to zero. Furthermore, this method can reduce computational complexity and be implemented in a low-cost Micro-Controller-Unit (MCU). Based on the numerical analysis, it can be concluded that the proposed recursive algorithm can calculate the unknown parameters reliably and accurately for most MEMS triaxial accelerometers available in the market. Additionally, this method is experimentally validated by comparing the output estimations before and after calibration under various scenarios, which further confirms its feasibility and effectiveness for online TA calibration.
Ye, L, Guo, Y & Su, SW 2017, 'An Efficient Autocalibration Method for Triaxial Accelerometer', IEEE Transactions on Instrumentation and Measurement, vol. 66, no. 9, pp. 2380-2390.
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© 1963-2012 IEEE. This paper investigates the autocalibration of microelectromechanical systems (MEMS) triaxial accelerometer (TA) based on experimental design (DoE). First, for a special 6-parameter second-degree model, a six-point experimental scheme is proposed, and its G-optimality has been proven based on optimal DoE. Then, a new linearization approach is introduced, by which the TA model for autocalibration can be simplified as the expected second-degree form so that the proposed optimal experimental scheme can be applied. To reliably estimate the model parameter, a convergence-guaranteed iterative algorithm is also proposed, which can significantly reduce the bias caused by linearization. Thereafter, the effectiveness and robustness of the proposed approach have been demonstrated by simulation. Finally, the proposed calibration method has been experimentally verified using two typical types of MEMS TA, and desired experimental results effectively demonstrate the efficiency and accuracy of the proposed calibration approach.
Yoshizawa, S & Miyanaga, Y 2017, 'W-04 NEXUS-the Next Generation e-Learning System-and FPGA Hardware Design Platform(International Session)', JSEE Annual Conference International Session Proceedings, vol. 2011, pp. 28-31.
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FPGA (Field Programmable Gate Array) is a widely known logic device which implements its internal circuit by programming. It has been mainly used in computer and LSI engineers as a prototype of LSI development. Currently, researchers who are in other fields keep their eyes on FPGA design and challenge to implement their sophisticated methods and applications into hardware. However, researchers who do have LSI design experiences must overcome barriers such as learning hardware knowledge and setup of FPGA design environments. Our developed platform named as 'NEXUS' (Next-generation EXtra University-education System) provides FPGA research and education environment by e-Learning system and remote controlled FPGA, which guarantees a smooth collaboration between interdisciplinary researchers on FPGAs. We present the NEXUS platform and report the interdisciplinary project of 'high-speed information search on FPGAs' as instances by utilization of this platform. In the project, we have studied the FPGA implementations in wireless communication and regular expression matching.
Yu, Y, Konstantinou, G, Townsend, CD, Aguilera, RP & Agelidis, VG 2017, 'Delta-Connected Cascaded H-Bridge Multilevel Converters for Large-Scale Photovoltaic Grid Integration', IEEE Transactions on Industrial Electronics, vol. 64, no. 11, pp. 8877-8886.
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© 1982-2012 IEEE. The cascaded H-bridge (CHB) converter is becoming a promising candidate for use in next generation large-scale photovoltaic (PV) power plants. However, solar power generation in the three converter phase-legs can be significantly unbalanced, especially in a large geographically-dispersed plant. The power imbalance between the three phases defines a limit for the injection of balanced three-phase currents to the grid. This paper quantifies the performance of, and experimentally confirms, the recently proposed delta-connected CHB converter for PV applications as an alternative configuration for large-scale PV power plants. The required voltage and current overrating for the converter is analytically developed and compared against the star-connected counterpart. It is shown that the delta-connected CHB converter extends the balancing capabilities of the star-connected CHB and can accommodate most imbalance cases with relatively small overrating. Experimental results from a laboratory prototype are provided to validate the operation of the delta-connected CHB converter under various power imbalance cases.
Zha, X, Ni, W, Zheng, K, Liu, RP & Niu, X 2017, 'Collaborative Authentication in Decentralized Dense Mobile Networks With Key Predistribution', IEEE Transactions on Information Forensics and Security, vol. 12, no. 10, pp. 2261-2275.
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© 2017 IEEE. Challenges of authentication in decentralized mobile networks arise from frequently changing topologies and unreliable contention-based transmissions. We propose a new protocol to speed up authentications, reduce communication costs, and support opportunistic routing under fast-changing topologies. Key pairs are predistributed across the network. Nodes that predistributed the same pair can instantly verify and route messages for each other in an opportunistic and cooperative fashion, combating fast-changing topologies. We also enable a node to increasingly combine unauthenticated messages and a new message for signature or message authentication code generation, while trying different keys on-the-fly. The messages can be verified altogether, once a key is matched. The communication overhead, thus, becomes independent of the number of keys tried. Closed-form expressions for authentication rate, delay, and throughput are derived through a new three-dimensional Markov model. Validated by simulations, analytical results corroborate the robustness of the proposed protocol against changing topologies, as well as the substantially improved resistance to collusion attacks, as compared with the state of the art.
Zhang, C, Li, Y, Li, J, Yang, Q & Zhu, J 2017, 'Measurement of Three-Dimensional Magnetic Properties With Feedback Control and Harmonic Compensation', IEEE Transactions on Industrial Electronics, vol. 64, no. 3, pp. 2476-2485.
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© 2016 IEEE. Three-dimensional (3-D) magnetic fluxes exist in rotating electric machines and T-joints of three-phase power transformers, and may cause local overheating in these devices. In this paper, 3-D magnetic properties of the core materials are measured by an improved 3-D magnetic property tester. First, the 3-D magnetization system is modeled by the voltage and flux linkage equations. Their parameters including the self and mutual inductances and nonlinear impedance are analyzed by the finite element analysis and measured by experiments. Second, a magnetic feedback method in the frequency domain is proposed to obtain the desired magnetization loci. Third, when the specimen is in deep magnetic saturation, the harmonics of magnetic flux density waveform would affect the shape of the corresponding magnetic field strength loci and the accuracy of loss computation. Thus, a waveform compensation method is proposed to eliminate the effects of harmonics. Fourth, the tensor effects of H coils are eliminated by averaging the results of clockwise and counterclockwise rotational experiments. Finally, the 3-D magnetic test system with feedback control, harmonics compensation, and automated data processing is developed. By using the 3-D magnetic tester, samples of nonoriented silicon sheet steel are measured with various excitation models and the results are more reliable than those obtained by experiments without feedback and harmonics compensation.
Zhang, C, Zhu, JG, Tong, WM & Han, XY 2017, 'Strength analysis and design of high speed interior permanent magnet rotor', Dianji yu Kongzhi Xuebao/Electric Machines and Control, vol. 21, no. 12, pp. 43-50.
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In order to solve the problem of high speed centrifugal force, the rotor strength is analyzed for the design of interior permanent magnet rotor. Based on the principle of rotor centrifugal force, the analytical formula of rotor strength was deduced. The correctness of analytical calculation was verified by finite element method. In order to improve the mechanical reliability of the rotor, the rotor segment structure was adopted. The extra magnetic rib can disperse the centrifugal force of rotor. Also, the effect of rib number and size on the strength and leakage performance was analyzed by finite element method. The design rules of the segmented rotor were summarized. Based on the analysis of rotor strength and electromagnetic, a high speed interior permanent magnet rotor with rated power of 15 kW and maximum speed of 30000 r/min was designed and tested. It provides references for the design of high speed interior permanent magnet rotor.
Zhang, G & Heusdens, R 2017, 'Distributed Optimization Using the Primal-Dual Method of Multipliers', IEEE Transactions on Signal and Information Processing over Networks, vol. 4, no. 1, pp. 173-187.
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In this paper, we propose the primal-dual method of multipliers (PDMM) fordistributed optimization over a graph. In particular, we optimize a sum ofconvex functions defined over a graph, where every edge in the graph carries alinear equality constraint. In designing the new algorithm, an augmentedprimal-dual Lagrangian function is constructed which smoothly captures thegraph topology. It is shown that a saddle point of the constructed functionprovides an optimal solution of the original problem. Further under both thesynchronous and asynchronous updating schemes, PDMM has the convergence rate ofO(1/K) (where K denotes the iteration index) for general closed, proper andconvex functions. Other properties of PDMM such as convergence speeds versusdifferent parameter- settings and resilience to transmission failure are alsoinvestigated through the experiments of distributed averaging.
Zhang, T, Cai, Z, Yang, Y, Bao, J & Wang, Y 2017, 'Compact tunable lowpass filter with sharp roll‐off and low insertion loss', Microwave and Optical Technology Letters, vol. 59, no. 10, pp. 2619-2623.
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AbstractA novel continuously tunable lowpass filter (LPF) with compact size, sharp roll‐off and low insertion loss is presented in this paper. The filter employs two varactor diodes, a pair of open‐ended coupled lines and a U‐shape step impedance line (SIL) with an open‐ended stub loaded at the center of the SIL to form a very compact layout. The odd‐ and even‐mode analysis and equivalent circuit model are demonstrated for estimation of the transmission characteristics. Tuning the DC voltage applied on the varactor diodes, the varactor capacitance accordingly changes leading to a varying cutoff frequency fc. The measured results show that the achieved 3‐dB fc tuning range is 60.6% (1.15–2.15 GHz). The measured insertion loss (IL) and roll‐off rate are 0.2‐0.4 dB and 50–73 dB/GHz, respectively. The overall size of the LPF is only 0.005λg2, which shows a competitive advantage comparing with the state‐of‐the‐art work.
Zhang, T, Gao, X, Wang, W, Du, J, Pegrum, C & Guo, YJ 2017, 'A 36 GHz HTS MMIC Josephson Mixer—Simulation and Measurement', IEEE Transactions on Applied Superconductivity, vol. 27, no. 4, pp. 1-5.
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© 2002-2011 IEEE. Modeling, simulation, and measurement of a compact 36 GHz high-temperature superconducting (HTS) monolithic Josephson junction mixer are presented in this paper. A full HTS microwave monolithic integrated circuit (MMIC) simulation was carried out for the circuit combining HTS passive devices and the Josephson junction. Optimal impedance matching and bias conditions were investigated, and the circuit layout was designed accordingly. The HTS circuit has a compact dimension of 5 × 4 × 0.3 mm 3 , including filters, resonators, and impedance matching circuits. The HTS MMIC mixer was fabricated and packaged with an LNA to realize a receiver front end with a total dimension of 28 × 25 × 15 mm 3 . Measurement result showed an overall conversion gain around 35 dB, with local oscillator driving power around -45 dBm at operating temperature of 40 K.
Zhang, T, Jia, W, He, X & Yang, J 2017, 'Discriminative Dictionary Learning With Motion Weber Local Descriptor for Violence Detection', IEEE Transactions on Circuits and Systems for Video Technology, vol. 27, no. 3, pp. 696-709.
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© 1991-2012 IEEE. Automatic violence detection from video is a hot topic for many video surveillance applications. However, there has been little success in developing an algorithm that can detect violence in surveillance videos with high performance. In this paper, following our recently proposed idea of motion Weber local descriptor (WLD), we make two major improvements and propose a more effective and efficient algorithm for detecting violence from motion images. First, we propose an improved WLD (IWLD) to better depict low-level image appearance information, and then extend the spatial descriptor IWLD by adding a temporal component to capture local motion information and hence form the motion IWLD. Second, we propose a modified sparse-representation-based classification model to both control the reconstruction error of coding coefficients and minimize the classification error. Based on the proposed sparse model, a class-specific dictionary containing dictionary atoms corresponding to the class labels is learned using class labels of training samples. With this learned dictionary, not only the representation residual but also the representation coefficients become discriminative. A classification scheme integrating the modified sparse model is developed to exploit such discriminative information. The experimental results on three benchmark data sets have demonstrated the superior performance of the proposed approach over the state of the arts.
Zhang, T, Jia, W, Yang, B, Yang, J, He, X & Zheng, Z 2017, 'MoWLD: a robust motion image descriptor for violence detection', Multimedia Tools and Applications, vol. 76, no. 1, pp. 1419-1438.
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© 2015, Springer Science+Business Media New York. Automatic violence detection from video is a hot topic for many video surveillance applications. However, there has been little success in designing an algorithm that can detect violence in surveillance videos with high performance. Existing methods typically apply the Bag-of-Words (BoW) model on local spatiotemporal descriptors. However, traditional spatiotemporal features are not discriminative enough, and also the BoW model roughly assigns each feature vector to only one visual word and therefore ignores the spatial relationships among the features. To tackle these problems, in this paper we propose a novel Motion Weber Local Descriptor (MoWLD) in the spirit of the well-known WLD and make it a powerful and robust descriptor for motion images. We extend the WLD spatial descriptions by adding a temporal component to the appearance descriptor, which implicitly captures local motion information as well as low-level image appear information. To eliminate redundant and irrelevant features, the non-parametric Kernel Density Estimation (KDE) is employed on the MoWLD descriptor. In order to obtain more discriminative features, we adopt the sparse coding and max pooling scheme to further process the selected MoWLDs. Experimental results on three benchmark datasets have demonstrated the superiority of the proposed approach over the state-of-the-arts.
Zhang, T, Pegrum, C, Du, J & Guo, YJ 2017, 'Simulation and measurement of a Ka-band HTS MMIC Josephson junction mixer', Superconductor Science and Technology, vol. 30, no. 1, pp. 015008-015008.
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© 2016 IOP Publishing Ltd. We report modeling and simulation results for a Ka band high-temperature superconducting (HTS) monolithic microwave integrated circuit (MMIC) Josephson junction mixer. A Verilog-A model of a Josephson junction is established and imported into the system simulator to realize a full HTS MMIC circuit simulation containing the HTS passive circuit models. Impedance matching optimization between the junction and passive devices is investigated. Junction DC I-V characteristics, current and local oscillator bias conditions and mixing performance are simulated and compared with the experimental results. Good agreement is obtained between the simulation and measurement results.
Zhang, Y, Li, P, Zhu, X, Su, SW, Guo, Q, Xu, P & Yao, D 2017, 'Extracting time-frequency feature of single-channel vastus medialis EMG signals for knee exercise pattern recognition', PLOS ONE, vol. 12, no. 7, pp. e0180526-e0180526.
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The EMG signal indicates the electrophysiological response to daily living of activities, particularly to lower-limb knee exercises. Literature reports have shown numerous benefits of the Wavelet analysis in EMG feature extraction for pattern recognition. However, its application to typical knee exercises when using only a single EMG channel is limited. In this study, three types of knee exercises, i.e., flexion of the leg up (standing), hip extension from a sitting position (sitting) and gait (walking) are investigated from 14 healthy untrained subjects, while EMG signals from the muscle group of vastus medialis and the goniometer on the knee joint of the detected leg are synchronously monitored and recorded. Four types of lower-limb motions including standing, sitting, stance phase of walking, and swing phase of walking, are segmented. The Wavelet Transform (WT) based Singular Value Decomposition (SVD) approach is proposed for the classification of four lower-limb motions using a single-channel EMG signal from the muscle group of vastus medialis. Based on lower-limb motions from all subjects, the combination of five-level wavelet decomposition and SVD is used to comprise the feature vector. The Support Vector Machine (SVM) is then configured to build a multiple-subject classifier for which the subject independent accuracy will be given across all subjects for the classification of four types of lower-limb motions. In order to effectively indicate the classification performance, EMG features from time-domain (e.g., Mean Absolute Value (MAV), Root-Mean-Square (RMS), integrated EMG (iEMG), Zero Crossing (ZC)) and frequency-domain (e.g., Mean Frequency (MNF) and Median Frequency (MDF)) are also used to classify lower-limb motions. The five-fold cross validation is performed and it repeats fifty times in order to acquire the robust subject independent accuracy. Results show that the proposed WT-based SVD approach has the classification accuracy of 91.85%±0.88% which...
Zhang, Y, Su, S, Savkin, A, Celler, B & Nguyen, H 2017, 'Multiloop Integral Controllability Analysis for Nonlinear Multiple-Input Single-Output Processes', Industrial & Engineering Chemistry Research, vol. 56, no. 28, pp. 8054-8065.
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© 2017 American Chemical Society. The decentralized integral controllability (DIC) for linear/nonlinear square processes implies the existence of stable decentralized controllers with integral actions capable of achieving offset-free control and detuning any subset of the control loops independently. However, the current version of the DIC cannot be directly applied to nonsquare processes specifically for multiple-input single-output (MISO) processes. This paper presents the new definition and theorem of multiloop integral controllability (MIC) to nonlinear MISO processes, and proposes the sufficient MIC conditions in order for such processes to guarantee decentralized unconditional stability under control loop failure as well as to achieve offset-free tracking performance. Two examples, the quadruple-tank system (model based) and the temperature control system, are modified as two-input single-output (TISO) plants and given to quantitatively interpret the effectiveness of the proposed MIC analysis where the desirable performance of both applications can be obtained.
Zhao, S, Cheng, E, Qiu, X, Burnett, I & Liu, JC-C 2017, 'Wind noise spectra in small Reynolds number turbulent flows', The Journal of the Acoustical Society of America, vol. 142, no. 5, pp. 3227-3233.
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Wind noise spectra caused by wind from fans in indoor environments have been found to be different from those measured in outdoor atmospheric conditions. Although many models have been developed to predict outdoor wind noise spectra under the assumption of large Reynolds number [Zhao, Cheng, Qiu, Burnett, and Liu (2016). J. Acoust. Soc. Am. 140, 4178–4182, and the references therein], they cannot be applied directly to the indoor situations because the Reynolds number of wind from fans in indoor environments is usually much smaller than that experienced in atmospheric turbulence. This paper proposes a pressure structure function model that combines the energy-containing and dissipation ranges so that the pressure spectrum for small Reynolds number turbulent flows can be calculated. The proposed pressure structure function model is validated with the experimental results in the literature, and then the obtained pressure spectrum is verified with the numerical simulation and experiment results. It is demonstrated that the pressure spectrum obtained from the proposed pressure structure function model can be utilized to estimate wind noise spectra caused by turbulent flows with small Reynolds numbers.
Zhao, S, Dabin, M, Cheng, E, Qiu, X, Burnett, I & Liu, JC-C 2017, 'On the wind noise reduction mechanism of porous microphone windscreens', The Journal of the Acoustical Society of America, vol. 142, no. 4, pp. 2454-2463.
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This paper investigates the wind noise reduction mechanism of porous microphone windscreens. The pressure fluctuations inside the porous windscreens with various viscous and inertial coefficients are studied with numerical simulations. The viscous and inertial coefficients represent the viscous forces resulting from the fluid–solid interaction along the surface of the pores and the inertial forces imposed on the fluid flow by the solid structure of the porous medium, respectively. Simulation results indicate that the wind noise reduction first increases and then decreases with both viscous and inertial coefficients after reaching a maximum. Experimental results conducted on five porous microphone windscreens with porosity from 20 to 60 pores per inch (PPI) show that the 40 PPI windscreen has the highest wind noise reduction performance, and this supports the simulation results. The existence of the optimal values for the viscous and inertial coefficients is explained qualitatively and it is shown that the design of the porous microphone windscreens should take into account both the turbulence suppression inside and the wake generation behind the windscreen to achieve optimal performance.
Zhao, Y, Di, H, Zhang, J, Lu, Y, Lv, F & Li, Y 2017, 'Region-based Mixture Models for human action recognition in low-resolution videos', Neurocomputing, vol. 247, pp. 1-15.
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© 2017 State-of-the-art performance in human action recognition is achieved by the use of dense trajectories which are extracted by optical flow algorithms. However, optical flow algorithms are far from perfect in low-resolution (LR) videos. In addition, the spatial and temporal layout of features is a powerful cue for action discrimination. While, most existing methods encode the layout by previously segmenting body parts which is not feasible in LR videos. Addressing the problems, we adopt the Layered Elastic Motion Tracking (LEMT) method to extract a set of long-term motion trajectories and a long-term common shape from each video sequence, where the extracted trajectories are much denser than those of sparse interest points (SIPs); then we present a hybrid feature representation to integrate both of the shape and motion features; and finally we propose a Region-based Mixture Model (RMM) to be utilized for action classification. The RMM encodes the spatial layout of features without any needs of body parts segmentation. Experimental results show that the approach is effective and, more importantly, the approach is more general for LR recognition tasks.
Zhi‐gang, L, Hao, Z, Hai‐feng, X, Jiang‐feng, Z, Xue‐ping, L & Xiao‐feng, S 2017, 'Robust DED based on bad scenario set considering wind, EV and battery switching station', IET Generation, Transmission & Distribution, vol. 11, no. 2, pp. 354-362.
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With the increasing penetration of wind power and electric vehicle (EV) into the power system, system operators face new challenges for system reliability and generation cost due to the intermittent of wind power. Furthermore, the randomly connected EVs at different time periods and locations add more uncertainty to the power system. In this study, uncertainties in wind power generation and EV charging load are modelled into the day-ahead dynamic economic dispatch (DED) problem, solution feasibility and robustness are discussed, and the bad scenario set is formulated for the day-ahead DED problem. In the obtained model, parameters can be used to adjust the positive bias or conservative bias, charging/discharging power of battery switch stations are also controlled to optimise the total cost of power system. To solve the optimisation problem, the multi-agent bacterial colony chemotaxis algorithm and a mutation strategy based on the cloud theory are developed. The simulation results show that the proposed method is effective, and battery switching station can help to reduce total cost by charging and discharging batteries.
Zhong, Y, Yang, Y, Zhu, X, Dutkiewicz, E, Shum, KM & Xue, Q 2017, 'An On-Chip Bandpass Filter Using a Broadside-Coupled Meander Line Resonator With a Defected-Ground Structure', IEEE Electron Device Letters, vol. 38, no. 5, pp. 626-629.
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© 2017 IEEE. An on-chip bandpass filter (BPF) is designed and fabricated in a 0.13-μm SiGe (Bi)-CMOS technology. This BPF consists of a broadside-coupled meander-line resonator (BCMLR) in conjunction with a defected-ground structure (DGS). By simply grounding a BCMLR, the resonator can be converted into a BPF. Further applying a DGS to this BPF, an additional transmission zero can be generated in the high-frequency band. To understand the fundamentals of this design, an $LC$-equivalent circuit is given for investigation of the transmission zeros and poles. The measured results show that the BPF has a center frequency at 33 GHz with a bandwidth of 18%. The minimum insertion loss is 2.6 dB, while the maximum stopband attenuation is 44 dB. The chip size, excluding the pads, is only 0.038 mm2 ( 0.126×0.3 mm2).
Zhong, Y, Yang, Y, Zhu, X, Dutkiewicz, E, Zhou, Z & Jiang, T 2017, 'Device-Free Sensing for Personnel Detection in a Foliage Environment', IEEE Geoscience and Remote Sensing Letters, vol. 14, no. 6, pp. 921-925.
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© 2017 IEEE. In this letter, the possibility of using device-free sensing (DFS) technology for personnel detection in a foliage environment is investigated. Although the conventional algorithm that based on statistical properties of the received-signal strength (RSS) for target detection at indoor or open-field environment has come a long way in recent years, it is still questionable if this algorithm is fully functional at outdoor with the changing atmosphere and ground conditions, such as a foliage environment. To answer this question, a variety of the measured data have been taken using different targets in a foliage environment. Applying these data along with support vector machine, the impact on detection accuracy due to different classification algorithms is studied. An algorithm that based on the extraction of the high-order cumulant (HOC) of the signals is presented, while the conventional RSS-based one is used as a benchmark. The measurement results show that the classification accuracy of the HOC-based algorithm is better than the RSS-based one by at least 17%. Moreover, to ensure the reliability of the HOC-based approach, the impact on classification accuracy due to different numbers of training samples and different values of signal-to-noise ratio is extensively verified using experimentally recorded samples. To the best of our knowledge, this is the first time that a DFS-based sensing approach is demonstrated to have a potential to distinguish between human and small-animal targets in a foliage environment.
Zhou, Y, Ni, W, Zheng, K, Liu, RP & Yang, Y 2017, 'Scalable Node-Centric Route Mutation for Defense of Large-Scale Software-Defined Networks', Security and Communication Networks, vol. 2017, pp. 1-13.
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Exploiting software-defined networking techniques, randomly and instantly mutating routes can disguise strategically important infrastructure and protect the integrity of data networks. Route mutation has been to date formulated as NP-complete constraint satisfaction problem where feasible sets of routes need to be generated with exponential computational complexities, limiting algorithmic scalability to large-scale networks. In this paper, we propose a novel node-centric route mutation method which interprets route mutation as a signature matching problem. We formulate the route mutation problem as a three-dimensional earth mover’s distance (EMD) model and solve it by using a binary branch and bound method. Considering the scalability, we further propose that a heuristic method yields significantly lower computational complexities with marginal loss of robustness against eavesdropping. Simulation results show that our proposed methods can effectively disguise key infrastructure by reducing the difference of historically accumulative traffic among different switches. With significantly reduced complexities, our algorithms are of particular interest to safeguard large-scale networks.
Zhu, G, Zhu, Y, Tong, W, Han, X & Zhu, J 2017, 'Thermal Analysis Techniques of Finite Formulation Method and the Application on Permanent Magnet Machines', Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering, vol. 37, pp. 152-161.
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The working performance of a permanent magnet synchronous machine (PMSM) is directly decided by the temperature rise distribution, thus making thermal analysis a key point in machine design. According to the fundamental principles of the finite formulation method (FFM) and the heat transfer theory, the implementation methods of the common boundary conditions in thermal analyses were presented. A FFM based high-precision model of the convective heat transfer boundary was established and illustrated in this paper. The temperature field of a 2D standard compute instance was analyzed by the original convective model and the modified one exhibited in this paper. Calculation Errors were discussed that confirmed the study. The 3-D temperature field distribution of a 2.1kW PMSM with an amorphous alloy (AA) core was analyzed by FFM and FEM with the same set of grids. Through the analyses between numerical results and the experimental ones, the superiority and the reliability of the FFM based thermal analysis techniques were confirmed. This paper has a reference value for the thermal analyses of PMSMs utilizing AA cores.
Zhu, G, Zhu, Y, Zhu, J, Tong, W & Han, X 2017, 'Thermal Analysis and Cooling System Design of a Permanent Magnet Traction Motor Using Computational Fluid Dynamics and Cell Method', Diangong Jishu Xuebao/Transactions of China Electrotechnical Society, vol. 32, no. 5, pp. 70-77.
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The rare earth permanent magnet synchronous machine(PMSM)has attracted extensive research attentions in the field of track transportation because of its superior characteristics of high efficiency and high power density.Because of its totally enclosed type mechanical structure, the load carrying capability is limited by the cooling system.This paper presents a design method of the auto circulating air-air cooling system for a permanent magnet traction motor with totally enclosed structure.Through an analysis of parameter sensitivities, the structural parameters of the cooling system are determined to maintain the temperature rise, maintenance demand, and cost within the acceptable engineering design limit.Finally, the finite formulation method(FFM)is used to analyze the 3-D thermal field distribution of the machine for determining the dimensions of the final structure.The results are verified by the 3-D computational fluid dynamics(CFD)analysis.
Zhu, HL, Chung, KL, Ding, C, Wei, G, Zhang, C & Guo, YJ 2017, 'Polarization-Rotated Waveguide Antennas for Base-Station Applications', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 1545-1548.
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© 2017 IEEE. A novel base-station antenna element is proposed. It consists of an artificial surface composed of parallel strips rotating in the polarization direction and a segment of a rectangular waveguide. The surface is designed on a single-sided substrate, which has the same area as the aperture of the waveguide. To achieve the polarization rotation, the parallel strips on the surface are rotated by 45° with respect to the orientation of the waveguide antenna. By adding the surface, the linear polarization direction of the rectangular waveguide antenna rotates by 45° to comply with the requirements of the cellular industry. To verify the simulation results, the proposed antenna was fabricated and measured. Results show that the antenna has an operating bandwidth from 698-960 MHz, where a stable radiation pattern is achieved.
Zhu, J, Zeng, JB & Guo, YG 2017, 'Investigation and Simulation on Magnetic Hysteresis Properties of Magnetorheological Fluid', IEEE Transactions on Industrial Electronics, vol. 64, no. 2, pp. 1611-1617.
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Magnetorheological fluid (MRF) materials are used in many devices as smart materials. However, the application of this material is limited to damper or vibration absorber because of the lack of understanding of its magnetic hysteresis properties. This paper systematically presents our recent investigation and simulation on the magnetic hysteresis properties of MRF materials. The measurement of its magnetic hysteresis property was accomplished by using a two-dimensional single sheet tester with an MRF sample container. An extended large-scale atomic/molecular massive parallel simulator, which is combined with the Stoner-Wohlfarth hysteresis model, was employed for simulating the magnetic hysteresis properties of MRF material. The measurement and simulation results are compared, analyzed, and discussed. The results will be useful for modeling of magnetic hysteresis properties of MRF materials.
Zhu, L, Tong, W, Han, X & Zhu, J 2017, 'Iron loss research of amorphous alloy motor by considering the influences of solidifying and annealing on stator core', COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36, no. 6, pp. 1612-1622.
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Purpose
The specific iron losses of amorphous alloy material are extremely low compared with silicon steel material. The iron losses of motors may reduce by replacing the silicon steel core with an amorphous alloy core. However, one drawback of amorphous alloy material is that the specific iron losses will increase a lot after the motor manufacturing process. This paper aims to study the influences of interlaminar insulator solidifying and annealing on amorphous alloy material. The iron losses of motors made of amorphous alloy and baseline silicon steel sheets are compared and discussed.
Design/methodology/approach
This paper opted for an exploratory study using the experimental analysis and loss separation methods. Two amorphous alloy cores are produced and tested. The iron losses of motors made of amorphous alloy and silicon steel sheets are calculated and compared based on the measured specific iron losses. Three wound amorphous alloy core samples are made and measured. The iron losses are separated and compared by considering the manufacturing influences.
Findings
This paper provides empirical insights about what change is brought in amorphous alloy material after manufacturing. The results have shown that, for amorphous alloy cores without the annealing process, the loss increase caused by solidifying is mainly the eddy current loss, while it is mainly the hysteresis loss component for annealed amorphous alloy cores.
Originality/value
This paper presents for the first time the measured results of manufactured amorphous alloy cores. This paper fulfils the need to manufacture amorphous al...
Zhu, L, Wang, R, Wang, Z & Yang, H 2017, 'TagCare: Using RFIDs to Monitor the Status of the Elderly Living Alone', IEEE Access, vol. 5, pp. 11364-11373.
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Zhu, L, Zhu, J, Tong, W & Han, X 2017, 'Analytical Calculation of Harmonic Losses of an Axial Flux Amorphous Motor Caused by PWM Inverter Supplying', Diangong Jishu Xuebao/Transactions of China Electrotechnical Society, vol. 32, no. 16, pp. 115-123.
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Amorphous alloys are considered as an appropriate core material for high-frequency motors because of their outstanding low power loss characteristics. When supplied by a PWM inverter, however, the harmonic losses of high-frequency motors will enormously increase. The key for designing and optimizing an amorphous alloy axial-flux permanent magnet motor is the fast and accurate calculation of harmonic losses during the original designing stage. In this paper, because of the large time consuming of three dimensional time step finite element analysis method, the present multilayer coupled model is further improved. An analytical method of air gap flux density is derived which can take high order carrier harmonics into account. The analytical methods of stator core losses and rotor eddy current losses are then deduced in consideration of the influence of eddy current reaction. The analytical calculation results of harmonic losses are compared with measured results and those obtained by the three dimensional FEA method. It is shown that the average calculation error of rotor losses is 9.69%, which means the improved analytical method features in high accuracy.
Zhu, L, Zhu, J, Tong, W & Han, X 2017, 'Analytical Method of No-Load Iron Losses of Axial Flux Amorphous Alloy Permanent Magnet Motor', Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering, vol. 37, no. 3, pp. 923-930.
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The core loss of axial flux permanent magnet motor will decrease a lot when the silicon steel core is replaced by the amorphous alloy core in consideration of the outstanding low power loss characteristics of amorphous alloy material, but the loss structure of amorphous alloy motor will be different from the silicon steel motor. The key for design and optimization an amorphous alloy axial flux permanent magnet motor is the fast and accurate calculation of no load iron losses during the original designing stage. In this paper, because of the large time consuming of three dimensional time step finite element analysis method, the present multilayer coupled model was further improved, the analytical methods of air gap flux density, stator core loss and permanent magnet eddy current loss were derived, and an analytical model of no load iron losses was then established. The analytical calculation results were compared with the results obtained by three dimensional FEA method, and it is shown that, the average calculation error of no load iron losses is 9.42%. The influences of slot width and air gap length to the no load losses were analyzed using the proposed analytical method, and the results show that, it is more effective to reduce the iron losses by narrowing the slot width.
Zhu, LF, Zhu, JG, Tong, WM & Han, XY 2017, 'Analysis of characteristics of power losses and efficiency of amorphous alloy permanent magnet motor', Dianji yu Kongzhi Xuebao/Electric Machines and Control, vol. 21, no. 7.
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In order to study the characteristics of power losses and efficiency of the permanent magnet motor when the silicon steel core is replaced by the amorphous alloy core, two permanent magnet motors are produced which have the same specifications. One core of the motors is made of silicon steel sheet and the other core of the motors is made of amorphous alloy material. The characteristics of power losses and efficiency of the two motors were measured at the same operating situation. Power losses were also analyzed at various load ratios by using finite element analysis. The results show that, the core loss of amorphous alloy motor is lower than that of the silicon steel motor when the load is light, and the efficiency of amorphous alloy motor is superior to silicon steel motor. But with the increase of load ratio, the core of amorphous alloy motor is poorly saturated, the waveform of MMF distorts a lot, and the losses caused by MMF harmonics are higher in amorphous alloy motor than that in the silicon steel motor, which leads to a reduction of superiority of efficiency with the increase of load ratio.
Zhu, R, Xu, W, Ye, C & Zhu, J 2017, 'Novel Heteropolar Radial Hybrid Magnetic Bearing With Low Rotor Core Loss', IEEE Transactions on Magnetics, vol. 53, no. 11, pp. 1-5.
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Zulfiqar, U, Tariq, W, Li, L & Liaquat, M 2017, 'A Passivity-Preserving Frequency-Weighted Model Order Reduction Technique', IEEE Transactions on Circuits and Systems II: Express Briefs, vol. 64, no. 11, pp. 1327-1331.
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© 2004-2012 IEEE. Frequency-weighted model order reduction techniques aim to yield a reduced order model whose output matches that of the original system in the emphasized frequency region. However, passivity of the original system is only known to be preserved in the single-sided weighted case. A frequency-weighted model order reduction technique is proposed, which guarantees the passive reduced models in the double-sided weighted case. A set of easily computable error bound expressions are also presented.
Abbasi, MH, Rajabi, A, Taki, M, Li, L, Zhang, J & Ghavidel, S 1970, 'Managing the cumulative distribution function of the profit: A producer risk management case', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia.
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© 2017 IEEE. This paper presents a new framework for risk consideration of participants in electricity markets. Current approaches add risk measures to stochastic problem formulation in order to control the variation of the profits (costs). However, in the proposed method, cumulative distribution function of profit is utilized and it is shaped based on the preferred risk levels of the producer (buyer). The features of this new method are compared with the current approaches based on a detailed case study performed on the problem of a producer participating in a three settlement market.
Abbasi, MH, Rajabi, A, Taki, M, Li, L, Zhang, J, Ghavidel, S & Ghadi, MJ 1970, 'Risk-constrained offering strategies for a price-maker demand response aggregator', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia.
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© 2017 IEEE. Offering strategy of a price-maker demand response aggregator (DRA) in a two-settlement market is presented in this paper. The aggregator minimizes its cost by offering energy and price bids in the day-ahead market and energy bids in the balancing market. On the other hand, DRA optimally manages the aggregated demands of a large number of electric vehicles and properly distributes them through the time. The problem is formulated as a stochastic mixed-integer nonlinear optimization problem. The risk of the problem is managed by conditional value-at-risk measure and finally, the proposed approach is numerically evaluated through a detailed case study.
Abeywickrama, HV, Jayawickrama, BA, He, Y & Dutkiewicz, E 1970, 'Algorithm for energy efficient inter-UAV collision avoidance', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, Australia, pp. 1-5.
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© 2017 IEEE. Unmanned Aerial Vehicles (UAV) are fast gaining popularity. Due to their many desired features, in the near future, UAVs will be an inevitable part of many fields. This increased use of UAVs, has given rise to the idea of multi-UAV systems, commonly known as UAV swarms, where a number of UAVs ranging from two to hundreds have to collaborate with each other and perform a common shared task or tasks. When sharing a common air space and flying in close proximity of each other, inter-UAV collision avoidance becomes an important factor in UAV swarms. Thus, for effective use of UAV swarms, it is essential to have an efficient inter-UAV collision avoidance mechanism. Although there are a number of suggested techniques, avoiding inter-UAV collisions while minimising the energy consumption of the UAV system is a challenge. In this paper, a Potential Field Method based algorithm to avoid collisions of a UAV system, considering the minimising of system energy usage, is suggested. We consider the energy consumption of a UAV system to depend on the distance travelled and the turns- A ngular changes, in trajectories. Our method reduces the angular changes in trajectories by an average of 36% and total travel distance by 6-8%. The total time taken to achieve targets is reduced by 3-14% depending on the scenario.
Abuhilaleh, M, Li, L, Begum, M & Zhu, J 1970, 'Power management and control strategy for hybrid AC/DC microgrids in autonomous operation mode', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia.
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© 2017 IEEE. The hybrid AC/DC microgrid structure is considered to be the future trend of power systems, due to the vital necessity of connecting more renewable energy sources and storage elements to supply modern AC and DC loads. This paper proposes a power sharing and control strategy for hybrid AC/DC microgrids using the droop control technique. A new structure of the hybrid microgrid is suggested by connecting different AC, and DC sub-grids by an interlinking converter. This can be symbolized by a bi-directional converter that acts as a rectifier when power flows from the AC sub-grid to the DC subgrid. And operates as an inverter when power flows from the DC subgrid to the AC one. The proposed structure and power management strategy also allow power flows between DC sides of the system through the AC subgrid as a common bus. Five scenarios of transferring power from one sub-grid to another are studied using. MATLAB/Simulink. The results indicate a high level of the system's felexibility in managing th power flow.
Afzal, MU & Esselle, KP 1970, 'Application of near-field phase transformation to steer the beam of high-gain antennas in two dimensions', 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, IEEE, San Diego, CA, pp. 1947-1948.
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Afzal, MU & Esselle, KP 1970, 'The use of near-field phase transformation to design a low-profile azimuthal beam scanning antenna system', 2017 International Conference on Electromagnetics in Advanced Applications (ICEAA), 2017 International Conference on Electromagnetics in Advanced Applications (ICEAA), IEEE, Verona, ITALY, pp. 750-753.
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Afzal, MU, Lalbakhsh, A & Esselle, KP 1970, 'Integration of sparse array feed and phase correction to design high gain resonant cavity antennas', 2017 Progress in Electromagnetics Research Symposium - Fall (PIERS - FALL), 2017 Progress in Electromagnetics Research Symposium - Fall (PIERS - FALL), IEEE, Singapore, SINGAPORE, pp. 2884-2887.
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Aghdam, MM, Aguilera, RP, Li, L & Zhu, J 1970, 'Fuzzy-based self-tuning model predictive direct power control of grid-connected multilevel converters', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia, pp. 1-6.
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© 2017 IEEE. This paper proposes a self-tuning model predictive direct power control (MPDPC) strategy for power flow control and power quality improvement in grid-connected power converters. At each sampling instant, a fuzzy logic controller is used to determine online the best weighting factor values for a given operating point. These values are then used to solve the multi-objective optimal control problem associated to the MPDPC. The optimal solution that minimizes the multi-objective cost function is chosen as the input (power switch state). The proposed method is examined through a case study and verified numerically via MAT LAB SIMULINK. A comparative study is conducted to demonstrate the effective performance of this approach. As a result of the proposed weighting factor online tuning, an improved performance in terms of total harmonic distortion and average switching frequency is attained when compared with fixed weighting factors.
Aghdam, MM, Li, L, Zhu, J, He, T & Zhang, J 1970, 'Time-delayed model predictive direct power control for vehicle to grid and grid to vehicle applications', IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, IEEE, Beijing, China, pp. 4662-4667.
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© 2017 IEEE. This paper presents a time-delayed model predictive control for power converters used in vehicle to grid and grid to vehicle systems. Finite-based model predictive control has proven to be an alternate digital control method for power converters. However, there are some real-time implementation issues, including specifically time delay, that have to be addressed in order to achieve the system reliability and stability as well as better performance. The proposed method compensates the delay time arising from measuring, calculating, and applying the optimal control sequence in the digital processor. In this way, the delay time is considered in the system input and optimal switching states are applied to the converter once they are available. The proposed method is studied through two benchmarks and verified numerically via MATLAB/Simulink.
Aguilera, RP, Acuna, P, Su, X, Lezana, P & McGrath, B 1970, 'Sequential Phase-Shifted Model Predictive Control for multicell power converters', 2017 IEEE Southern Power Electronics Conference (SPEC), 2017 IEEE Southern Power Electronics Conference (SPEC), IEEE, Chile.
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© 2017 IEEE. This paper proposes a sequential Phase-Shifted Model Predictive Control (PS-MPC) strategy for multicell power converters. The key novelty of this proposal lies in the way the predictive control strategy is formulated to fully exploit a phase-shifted pulse width modulation (PS-PWM) stage. Normally, when using a linear controller along with a standard PS-PWM stage, the modulator receives the same duty cycle for all the internal carriers. In contrast, by means of an appropriate choice of synchronized models for each carrier, the proposed predictive controller obtains independent optimal duty cycles for each carrier in a sequential manner. This allows one to formulate the optimal control problem to govern not only the output current but also the internal floating capacitor voltages, similarly to the finite-control-set MPC (FCS-MPC) case. As a result, the proposed sequential PS-MPC can attain a faster floating voltage balancing dynamic when compared to a standard PS-PWM implementation. Moreover, it generates a fixed-spectrum in the steady state with a constant commutation rate, which outperforms a standard FCS-MPC strategy. Simulation results of the proposed sequential PS-MPC strategy governing a single-phase four-level flying capacitor converter are presented to verify its dynamic and steady-state performance.
Ahmed, F, Chowdhury, MHM & Rahman, AMA 1970, 'A multiband MIMO antenna for future generation handset applications', 2017 International Conference on Electrical, Computer and Communication Engineering (ECCE), 2017 International Conference on Electrical, Computer and Communication Engineering (ECCE), IEEE, Coxs Bazar, BANGLADESH, pp. 91-94.
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Ahmed, F, Hasan, N & Chowdhury, MHM 1970, 'A compact low-profile ultra wideband antenna for biomedical applications', 2017 International Conference on Electrical, Computer and Communication Engineering (ECCE), 2017 International Conference on Electrical, Computer and Communication Engineering (ECCE), IEEE, Coxs Bazar, BANGLADESH, pp. 87-90.
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Ahmed, F, Hasan, N & Rahman, AMA 1970, 'A compact planar multiple-input multiple-output (MIMO) antenna for ultra-wideband applications', 2017 3rd International Conference on Electrical Information and Communication Technology (EICT), 2017 3rd International Conference on Electrical Information and Communication Technology (EICT), IEEE, Khulna, BANGLADESH.
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Akter, MP & Lu, DD-C 1970, 'Model Predictive Controlled Active NPC Inverter for Voltage Stress Balancing Among the Semiconductor Power Switches', IOP Conference Series: Earth and Environmental Science, International Conference on Sustainable Energy Engineering, IOP Conference Series: Earth and Environmental Science, IOP Publishing, Perth, Australia, pp. 012019-012019.
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© Published under licence by IOP Publishing Ltd. This paper presents a model predictive controlled three-level three-phase active neutral-point-clamped (ANPC) inverter for distributing the voltage stress among the semiconductor power switches as well as balancing the neutral-point voltage. The model predictive control (MPC) concept uses the discrete variables and effectively operates the ANPC inverter by avoiding any linear controller or modulation techniques. A 4.0 kW three-level three-phase ANPC inverter is developed in the MATLAB/Simulink environment to verify the effectiveness of the proposed MPC scheme. The results confirm that the proposed model predictive controlled ANPC inverter equally distributes the voltage across all the semiconductor power switches and provides lowest THD (0.99%) compared with the traditional NPC inverter. Moreover, the neutral-point voltage balancing is accurately maintained by the proposed MPC algorithm. Furthermore, this MPC concept shows the robustness capability against the parameter uncertainties of the system which is also analyzed by MATLAB/Simulink.
Akter, MP, Lu, DD-C & Jianguo Zhu 1970, 'Model predictive controlled three-level active-neutral-point-clamped inverter with improved computational speed and stability, and balanced DC-link voltages', 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia (IFEEC 2017 - ECCE Asia), 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia (IFEEC 2017 - ECCE Asia), IEEE, Kaohsiung, Taiwan, pp. 116-121.
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© 2017 IEEE. This paper proposes an advanced model predictive control for the three-level active-neutral-point-clamp (ANPC) inverter in order to improve the system performance with fast dynamic response and ensure the stability of the controller. The proposed scheme is Lyapunov function based voltage mode control which utilizes the discrete behavior of the converter considering the unavoidable quantization errors between the controller and the control actions selected from the finite control set of the ANPC inverter. A three-level three-phase ANPC inverter model is developed in MATLAB/Simulink environment to verify the effectiveness of the proposed MPC scheme. The simulation results confirm the computational speed improvements of the proposed MPC algorithm without compromising the performance such as total harmonic distortion (THD) of the three-level ANPC inverter. Moreover, the stability of the proposed technique is ensured by the nonlinear system model. Furthermore, the dc-link capacitor voltage balancing is also accurately maintained by the proposed controller at all times.
Aldebei, K, Farhood, H, Jia, W, Nanda, P & He, X 1970, 'Sequential and Unsupervised Document Authorial Clustering Based on Hidden Markov Model', 2017 IEEE Trustcom/BigDataSE/ICESS, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, Sydney, pp. 379-385.
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© 2017 IEEE. Document clustering groups documents of certain similar characteristics in one cluster. Document clustering has shown advantages on organization, retrieval, navigation and summarization of a huge amount of text documents on Internet. This paper presents a novel, unsupervised approach for clustering single-author documents into groups based on authorship. The key novelty is that we propose to extract contextual correlations to depict the writing style hidden among sentences of each document for clustering the documents. For this purpose, we build an Hidden Markov Model (HMM) for representing the relations of sequential sentences, and a two-level, unsupervised framework is constructed. Our proposed approach is evaluated on four benchmark datasets, widely used for document authorship analysis. A scientific paper is also used to demonstrate the performance of the approach on clustering short segments of a text into authorial components. Experimental results show that the proposed approach outperforms the state-of-the-art approaches.
Al-Doghman, F, Chaczko, Z & Jiang, J 1970, 'A Review of Aggregation Algorithms for the Internet of Things', 2017 25th International Conference on Systems Engineering (ICSEng), 2017 25th International Conference on Systems Engineering (ICSEng), IEEE, Piscataway, USA, pp. 480-487.
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© 2017 IEEE. The Internet of Things (IoT) epitomizes the upcoming eminent transition in the world’s economy and human lifestyle where people and various objects are correlated within networks. Data Aggregation is a technique which can be used to mitigate Big Data challenges within IoT. This paper provides an overview of various approaches for aggregation of data in IoT infrastructure. A new class of reliable Data Aggregation algorithm is discussed as well. This new class of algorithm uses a consensus based aggregation with fault tolerance methodology in Fog Computing. The new approach allows promoting adaptive behavior and more efficient delivery of the aggregation outcomes to the ascendant node(s). The proposed method is fault tolerant and deals with nodes reliability issues.
Alenazy, WM & Chaczko, Z 1970, 'ETAM towards ICT teaching and learning studio for interactive learning in Information and Communication Technology', 2017 16th International Conference on Information Technology Based Higher Education and Training (ITHET), 2017 16th International Conference on Information Technology Based Higher Education and Training (ITHET), IEEE, Ohrid, Macedonia, pp. 1-11.
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© 2017 IEEE. Recent advances in Information and Communication Technology (ICT) have stimulated the need for adaptation of new models of teaching and learning in educational institutions. Since the beginning, the use of technology in education has gained a lot of attention and has been applied to many areas in the academic domain. The introduction of ICT has motivated scholars to find out how various ICT tools could be deployed and efficiently used. Due to rapid changes in ICT, an extended TAM (ETAM) has been developed to highlight the demand for using advanced ICT tools in the education process. The idea is to support the acceptance of technology implementations by modifying the conventional model with the pre-acknowledgement of additional elements that reflect the state of art technological advances. These additional factors aim to increase the motivation acceptance levels by instructors and students alike towards ICT teaching and learning studio style.
Allahaim, FS, Liu, L & Kong, X 1970, 'A Risk-Based Cost Contingency Estimation Model for Infrastructure Projects', ICCREM 2016, International Conference on Construction and Real Estate Management 2016, American Society of Civil Engineers, pp. 1293-1303.
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© 2017 American Society of Civil Engineers. Cost overrun of infrastructure projects is widespread and represents significant financial risks to stakeholders. The cluster analysis on the data of 41 commonly cited causes identified four dimensions of causes: scope changes, market and regulatory uncertainty, inadequate planning and control, and unforeseen circumstances. Subsequently, these four dimensions were then used to develop a risk-based cost contingency estimation model (RBCCEM) to improve the accuracy of cost contingency estimation which was then validated using a bootstrapping approach. The accuracy of the cost estimation measures was used to compare RBCCEM with other methods, namely fixed cost contingency, reference class forecasting, and a hybrid method. The findings suggested that RBCCEM could be more accurate as the error decreased by 10%. As a result, RBCCEM produces contingency estimates that are more consistent and brings project costs closer to actual costs than alternative approaches, such as reference class forecasting (RCF).
Al-Manasia, M, Chaczko, Z & Ounzar, A 1970, 'AHRC: An Optimized Cache Associativity', Proceedings - 18th IEEE International Conference on High Performance Computing and Communications, 14th IEEE International Conference on Smart City and 2nd IEEE International Conference on Data Science and Systems, HPCC/SmartCity/DSS 2016, IEEE International Conference on High Performance Computing and Communications, IEEE, Sydney, NSW, Australia, pp. 811-817.
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Hardware resources require efficient scaling because the future of computing technology seems to be intensive multithreaded. One of the main challenges in the scalability of computers hardware is the hierarchy of the memory. Chip-multiprocessors (CMPs) rely on large and multi-level hierarchies of caches to reduce cost of resources and improve systems performance. These multi-level hierarchies are the ones, which also help to solve the issue of limited bandwidth and minimize the latency of the main memory. Almost half of the area of the chip and a large percentage of the system energy is used by caches. One of the main problems limiting the scalability of cache hierarchies is called cache associativity. Caches consume a lot of energy to implement associative lookups. This affects the performance of the system by reducing the efficiency of caches. This paper describes a new design of cache that we called - Adaptive Hashing and Replacement Cache (AHRC). This design has the ability of maintaining high associativity with an advanced method of replacement policy. AHRC can improve associativity and maintain the number of possible locations, where each block is kept as small as possible. Several workloads were simulated on a large-scale CMP with AHRC as the last-level cache. We propose an Adaptive Reuse Interval Prediction (ARIP) scheme for AHRC, which is superior to the NRU scheme that was described by Seznec. Results demonstrate that AHRC has better energy efficiency and higher performance as compared to conventional caches. Additionally, large caches that utilize AHRC are the most suitable in many core CMPs to provide a more significant improvement and scalability than the smaller caches. However, AHRC with a higher-level replacement may lead to loss of energy for workloads that are not sensitive to the policy governing the replacement process.
Al-Soeidat, MR, Lu, DD-C & Jianguo Zhu 1970, 'A more accurate analog voltage-based photovoltaic maximum power point tracking technique', 2017 8th International Renewable Energy Congress (IREC), 2017 8th International Renewable Energy Congress (IREC), IEEE, Amman, Jordan, pp. 1-5.
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© 2017 IEEE. In this paper, an analog voltage based maximum power point tracking (MPPT) algorithm for individual photovoltaic (PV) panel is proposed. The fixed voltage reference method is the simplest method for tracking, but it does not give good MPPT efficiency because the MPP voltage point changes at different solar insolation levels. A roughly linear slope is formed when connecting the MPP points measured from the highest isolation level to the lowest. Utilizing this characteristic, a bipolar junction transistor BJT is used to implement a variable voltage reference that improves the accuracy of the maximum power point voltage when the insolation changes. The proposed circuit is simple and easy to implement and it can easily track the maximum power point without the need of a digital controller or PID controller, so the cost and circuit complexity is reduced.
Alturki, R & Gay, V 1970, 'Usability Testing of Fitness Mobile Application : Methodology and Quantitative Results', Computer Science & Information Technology (CS & IT), 7th International Conference on Computer Science, Engineering & Applications, Academy & Industry Research Collaboration Center (AIRCC), Copenhagen, Denmark.
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Obesity is a major health problem around the world. Saudi Arabia is a nation where obesity is increasing at an alarming rate. Mobile apps could help obese individuals but they need to be usable and personalized to be adopted by those users. This paper aims at testing the usability of a fitness mobile app” Twazon”, an app in Arabic language. This paper presents an extensive literature review on the attributes that improve the usability of fitness apps. Then, it explains our methodology and our set up of a trial to test the usability of Twazon app that is popular in Saudi Arabia. The usability attributes tested are effectiveness, efficiency, satisfaction, memorability, errors, learnability and cognitive load. The trial is done in collaboration with participants from the Armed Forces Hospitals - Taif Region in Saudi Arabia. The results highlight that the app failed to meet with the usability attributes.
Antunes, N, Pipiras, V & Veitch, D 1970, 'Skampling for the Flow Duration Distribution', 2017 29th International Teletraffic Congress (ITC 29), 2017 29th International Teletraffic Congress (ITC 29), IEEE, Genoa, Italy, pp. 63-71.
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© 2017 ITC Press. This paper concerns the problem of estimating the Internet flow duration distribution from indirect measurements due to network constraints. The aim is to estimate the distribution from observing: the possible superpositions (collisions) of sampled flow durations, the flow arrivals-to-departures times without identification of sampled flows and the number of sampled flows in progress. For each type of data available, we present estimators of the flow duration distribution, formulating the problem in queueing system terms. We also propose data streaming algorithms using sampling and sketching (through counters) to obtain the considered partial information from flows. At the core of this skampling (i.e. sampling and sketching) approach is the ability to tune the flow sampling probability for 'optimal' flow load onto sketch entries (queues). Finally, we present numerical results comparing the different estimators of the flow duration distribution using two real Internet traces.
Argha, A, Li, L, Ha, Q, Su, SW & Nguyen, HT 1970, 'Strong stability based robust sliding mode control.', ASCC, Asian Control Conference, IEEE, Gold Coast, QLD, Australia, pp. 588-593.
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© 2017 IEEE. In this paper, a new method for designing the robust Discrete-time Sliding Mode Control (DSMC) is proposed. To this end, firstly, the regular form based sliding mode control is reviewed. Then, according to the notion of strong stability and using scaling matrices (similarity transformation), a new method for considering the stability of discrete-time systems in the presence of general uncertainty term (matched and unmatched) is developed. Above all, in this paper, a new method to design the robust sliding surface according to the notion of strong stability is proposed. This problem is studied for both cases which system is or is not 'strongly stabilizable under state-feedback'.
Argha, A, Li, L, Su, SW & Nguyen, H 1970, 'Sparse Observer-Based Sliding Mode Control For Networked Control Systems', IFAC-PapersOnLine, World Congress of the International Federation of Automatic Control, Elsevier BV, Toulouse, France, pp. 12997-13002.
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© 2017 This paper is devoted to the problem of designing a sparse distributed output feedback discrete-time sliding mode control (ODSMC) for the networked systems. A distributed structure is employed in the discrete-time sliding mode control framework by exploiting other sub-systems’ information to improve the performance of each local controller/observer so that it can widen the applicability region of the given scheme. As the first step, a stability condition is derived for the overall closed-loop system obtained from applying ODSMC to the underlying interconnected system, by assuming a given structure for the control/observer network. In the second step, we explore a methodology to obtain a sparse control/observer network structure with the least possible number of communication links that satisfies the stability condition given in the first step. The boundedness of the obtained overall closed-loop system is analyzed and a bound is derived for the augmented system state which includes the closed-loop system state and the switching function.
Argha, A, Ye, L, Cao, K, Su, SW & Celler, BG 1970, 'Real-time identification of heart rate responses via auxiliary-model-based damped RLS scheme', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Seogwipo, South Korea, pp. 1312-1315.
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This study was devoted to developing a new auxiliary-model-based damped recursive least squares (AMB-DRLS) by which the heart rate dynamics can be identified in a real-time manner. Unlike the current conventional schemes for heart rate dynamics modeling, the proposed scheme can simultaneously identify the HR response dynamics and compensate for the existing HR variability while it can also cope with the blowup phenomenon. The performance of the proposed AMB-DRLS scheme was experimentally verified using fifteen healthy male participants who performed treadmill trials following single-cycle square wave protocol. The obtained results revealed a significant difference in goodness-of-fit for the considered parameter estimation schemes. As a result, we conclude that the proposed AMB-DRLS method is able to identify the heart rate response dynamics in a real-time manner while preventing the blowup phenomenon.
Asari, A, Guo, Y & Zhu, J 1970, 'Magnetic properties measurement of soft magnetic composite material (SOMALOY 700) by using 3-D tester', AIP Conference Proceedings, INTERNATIONAL CONFERENCE ON APPLIED PHYSICS AND ENGINEERING (ICAPE2016): Proceedings of the 2nd International Conference on Applied Physics and Engineering, Author(s), Penang, Malaysia.
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© 2017 Author(s). Core losses of rotating electrical machine can be predicted by identifying the magnetic properties of the magnetic material. The magnetic properties should be properly measured since there are some variations of vector flux density in the rotating machine. In this paper, the SOMALOY 700 material has been measured under x, y and z- axes flux density penetration by using the 3-D tester. The calibrated sensing coils are used in detecting the flux densities which have been generated by the Labview software. The measured sensing voltages are used in obtaining the magnetic properties of the sample such as magnetic flux density B, magnetic field strength H, hysteresis loop which can be used to calculate the total core loss of the sample. The results of the measurement are analyzed by using the Mathcad software before being compared to another material.
Asari, AR, Guo, Y & Zhu, J 1970, 'Core loss measurement under elliptical loci of magnetic flux density', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. Nowadays, rotating machines are widely used in most industries. Because of that, magnetic properties of soft magnetic material are actively studied under 1-D and 2-D magnetic flux excitations in order to estimate the total core loss produced by the material during the magnetization. SOMALOY 700 material, a soft magnetic composite material, is considered in this paper. 2-D magnetic measurement has been conducted by controlling magnetic flux densities to be in ellipse shape by using LabVIEW software. The core loss has been computed by using MathCAD software. The performance of this material at some frequencies is compared by plotting the loss curves in the same graph.
Asari, AR, Guo, Y & Zhu, J 1970, 'Measurement of magnetic properties of soft magnetic composite material (SOMALOY 700) by using 3-D magnetic tester', 19th International Conference on Electrical Machines and Systems, ICEMS 2016, International Conference on Electrical Machines and Systems, IEEE, Chiba, Japan, pp. 1-5.
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Core loss for rotating electrical machine can be predicted by identifying the magnetic properties of the particular magnetic material. The magnetic properties should be properly measured since there are some variations of vector flux density in the rotating machine. In this paper, a kind of soft magnetic composite material, SOMALOY 700, has been measured under one axis flux density penetration by using a 3-D magnetic tester. The LabVIEW has been used to measure the induced voltages of B (magnetic flux density) and H (magnetic field strength) sensing coils. The voltages are used in obtaining the magnetic properties of the sample such as B, H, hysteresis loop and core loss by using the Mathcad software.
Attawibulkul, S, Kaewkamnerdpong, B & Miyanaga, Y 1970, 'Noisy speech training in MFCC-based speech recognition with noise suppression toward robot assisted autism therapy', 2017 10th Biomedical Engineering International Conference (BMEiCON), 2017 10th Biomedical Engineering International Conference (BMEiCON), IEEE.
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Azizivahed, A, Ghavidel, S, Ghadi, MJ, Li, L & Zhang, J 1970, 'A novel reliability oriented bi-objective unit commitment problem', 2017 Australasian Universities Power Engineering Conference (AUPEC), 2017 Australasian Universities Power Engineering Conference (AUPEC), IEEE, Melbourne, Australia, pp. 1-6.
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© 2017 IEEE. This paper presents a new solution to unit commitment for single-objective and multi-objective frameworks. In the first step, the total expected energy not supplied (TEENS) is proposed as a separate reliability objective function and at the next step, the multi-objective Pareto front strategy is implemented to simultaneously optimize the cost and reliability objective functions. Additionally, an integer based codification of initial solutions is added to reduce the dimension of ON/OFF status variables and also to eliminate the negative influence of penalty factor. The modified invasive weed optimization (MIWO) algorithm is also developed to optimally solve the proposed problem. The obtained solutions are compared with results in the literature which confirms the applicability and superiority of the proposed algorithm for a 10-unit system and 24-hour scheduling horizon.
Azizivahed, A, Ghavidel, S, Ghadi, MJ, Li, L & Zhang, J 1970, 'Multi-area economic emission dispatch considering load uncertainty', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia.
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© 2017 IEEE. Multi-area economic emission dispatch problem provides an optimal schedule for active power of generators and interchange active power between different areas by considering the operational limitations such as balance between generation and consumption, tie-line capacity limitation, generators output constraint, and transmission losses. In this paper, a hybrid method based on shuffled frog leaping algorithm (SFLA) and particle swarm optimization (PSO) is presented to achieve better solution. Furthermore, the stochastic nature of energy consumption is modeled as uncertainty source using scenario reduction technique to achieve the results which are closer to the real condition. The performance of the proposed approach is elaborated in two test systems with different scales including 10-generator with three-area and 40-generator with four-area. The obtained results are compared with those available in the literature to show the effectiveness of the proposed approach.
Azizivahed, A, Ghavidel, S, Ghadi, MJ, Li, L & Zhang, J 1970, 'New energy management approach in distribution systems considering energy storages', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia.
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© 2017 IEEE. This paper presents a new method for energy management in distribution networks in the presence of energy storage, solar photovoltaic (PV) systems and diesel generators. Achieving optimal charge and discharge pattern for batteries and optimal diesel generator output with minimal operation cost are the main goal of this paper. The innovation of this paper is to consider the network effect on the underlying method with operational limitations and power-flow constraints such as power loss, voltage and current limitation. The proposed problem is solved for 24-hour time horizon, and the modified imperialist competitive algorithm (ICA) is also developed using mutation strategy to optimally solve the problem. Finally, to show the good performance and supremacy of the proposed method, a 33-bus IEEE standard test system is applied.
Baba, AA, Hashmi, RM & Esselle, KP 1970, 'Investigation of large directivity bandwidth in multilayer resonant cavity antennas', 2017 11th European Conference on Antennas and Propagation (EUCAP), 2017 11th European Conference on Antennas and Propagation (EUCAP), IEEE, Paris, FRANCE, pp. 1139-1142.
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Baba, AA, Hashmi, RM, Esselle, KP & Weily, AR 1970, 'On the use of external MATLAB-based optimization with full-wave simulation to design resonant cavity antennas (Special session)', 2017 IEEE International Conference on Computational Electromagnetics (ICCEM), 2017 IEEE International Conference on Computational Electromagnetics (ICCEM), IEEE, pp. 333-335.
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© 2017 IEEE. In this paper, a method to combine MATLAB-based optimization with a 3D electromagnetic simulator is described. The work-flow is presented using five main files (.m,.text,.bas,.sig and.rd1), which are required to establish the connection between the two software systems. Speed constrained particle swarm optimization (SMPSO) algorithm was implemented in MATLAB, which utilized the transient 3D simulator of CST Microwave Studio to carry out iterative full-wave analyses during the optimization process. As a design example, this customized optimization method was then employed to maximize the directivity-bandwidth product (DBP) of a mono-slab resonant cavity antenna (RCA). This optimization yielded a compact RCA, with a peak directivity of 21dBi and an extremely large directivity-bandwdith of 56%. The DBP of this optimized RCA is around 6500 and its total area is only 5.6λ20.
Baba, AA, Hashmi, RM, Esselle, KP & Weily, AR 1970, 'Two-level optimization of a stepped dielectric superstrate to increase gain of a resonant cavity antenna', 2017 International Conference on Electromagnetics in Advanced Applications (ICEAA), 2017 International Conference on Electromagnetics in Advanced Applications (ICEAA), IEEE, Verona, ITALY, pp. 1131-1133.
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Basnet, S, Jayawickrama, BA, He, Y & Dutkiewicz, E 1970, 'Considering switching overhead for transmit power allocation for GAA in spectrum access system', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, QLD, Australia, pp. 1-5.
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© 2017 IEEE. To enable spectrum sharing the Federal Communication Commission (FCC) has proposed the Spectrum Access System (SAS). In SAS General Authorised Access (GAA) can opportunistically access any part of the 3.5 GHz band. In SAS prior information regarding the time usage of spectrum is not provided by Priority Access Licensee (PAL) and when PAL operation starts the GAA needs to ensure they do not cause interference above a predetermined threshold. In this work we propose a method for GAA Citizen Broadband Radio Service Devices (CBSDs) to switch to different channel considering the probability of spectrum utilisation of GAA. Switching overhead is the time delay when switching the channel from one to another. In our work we proposed the method to calculate switching overhead and maximised average sum capacity of GAA CBSDs considering switching overhead and Root Mean Square (RMS) interference at PAL protection area. Simulations result shows that average sum capacity of GAA CBSDs can be maximised using the proposed method.
Basnet, S, Jayawickrama, BA, He, Y, Dutkiewicz, E & Mueck, MD 1970, 'Opportunistic Access to PAL Channel for Multi-RAT GAA Transmission in Spectrum Access System', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, NSW, Australia, pp. 1-5.
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© 2017 IEEE. Spectrum Access System (SAS) is a three tier spectrum sharing framework proposed by the FCC. In this framework the aggregate interference of tier-3 General Authorised Access (GAA) users should be below a predetermined threshold anywhere within the tier-2 Priority Access Licensee (PAL) exclusion zone. GAA are expected to use a diverse range of Radio Access Technologies (RATs) with different levels of loading. We propose an optimal transmit power and probability of spectrum utilisation allocation scheme for GAA users that meets the average aggregate interference constraint within the GAA network. Most of the capacity maximisation studies consider the instantaneous aggregated interference from secondary users. In this paper we present an average aggregated interference method to optimise the capacity of GAA users in a single channel. Simulation results suggest that we can significantly increase the capacity of the channel by considering the probability spectrum utilisation of GAA users.
Bautista, MG, Zhu, F, Nguyen, DN & Dutkiewicz, E 1970, 'Double-Balanced Gilbert Mixer with Current Bleeding for RF Front-End Using 0.13µm SiGe BiCMOS Technology', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. This paper presents the design of a differential double-balanced Gilbert mixer in 0.13 um SiGe BiCMOS technology. A current-bleeding injection technique is adopted to increase the bias current at the driver stage without causing overvoltage headroom at the differential pair stage. This mechanism improves the performance in terms of conversion gain, linearity and noise figure. The proposed mixer achieves 10.7 dB conversion gain, 15 dB noise figure, -1.67 dBm 1-dB compression point, and 5 dBm IIP3. The designed double balanced Gilbert mixer with current bleeding is part of an integrated RF front-end for full duplex radio applications in the 2.4 GHz band and occupies an area of 0.1002 × 0.0748 mm2 excluding the pads.
Bautista, MG, Zhu, JB, Zhu, F, Yang, Y & Dutkiewicz, E 1970, 'Design of on-chip quadrature hybrid (3dB) branch-line couplers in 0.13-μm SiGe technology for millimetre-wave applications', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, QLD, Australia, pp. 1-5.
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© 2017 IEEE. In this paper, design of miniaturized on-chip quadrature hybrid branch-line coupler is investigated. The motivation of this work is to minimize the footprint of the designed coupler while maintaining high performance of the circuit in the mm-wave band spectrum. Three examples are implemented in a standard (Bi)-CMOS process for millimetre wave applications. Excluding the pads, the chip size of the conventional design is 0.35 mm2, and the proposed two other designs structures are 0.26 mm2 and 0.21 mm2, respectively, which indicates an area reduction by 13% and 30% respectively.
Begum, M, Abuhilaleh, M, Li, L & Zhu, J 1970, 'Distributed secondary voltage regulation for autonomous microgrid', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney.
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© 2017 IEEE. This research addresses the control problem of microgrids and presents a robust distributed secondary control system for voltage regulation of an islanded microgrid with droop-controlled and inverter-based distributed generators (DGs). A consensus-based distributed control approach is proposed to restore the voltage and frequency of the islanded microgrid to the reference values for all DGs within a very short time. The proposed method is flexible to system topology variations which AIDS the plug-and-play operation of microgrid. An autonomous micogrid test system consisting of four DGs is constructed in MATLAB using SimPowerSystem Toolbox to test the proposed design method, and the simulation results show the effectiveness of the proposed control strategy. The performance of the proposed controller is shown through several test case studies.
Begum, M, Li, L & Zhu, J 1970, 'Distributed control techniques for autonomous AC Microgrid-A brief review', 2017 IEEE Region 10 Humanitarian Technology Conference (R10-HTC), 2017 IEEE Region 10 Humanitarian Technology Conference (R10-HTC), IEEE, Dhaka, Bangladesh, pp. 357-362.
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© 2017 IEEE. Distributed generation (DG) is performing progressively significant part in modern power systems. The main objective of this research is to provide a brief review of distributed control structures used so far to control an autonomous AC microgrid system. The distributed control for both grid-connected and autonomous microgrid is current developments for their several advantages compared to conventional central control system comprising the system trustworthiness, lessening its sensitivity to failures, and removing the necessity for a central computing and communication unit. The complete control scheme is divided into three basic control levels, such as primary, secondary and tertiary control level and control structures are considered here for autonomous operation mode. Trends and different approaches used until now, in above control levels are distinctly stated for understanding a brief overview.
Beiranvand, A, Abuhilaleh, M & Li, L 1970, 'A novel method for optimizing distributed generation in distribution networks using the game theory', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney.
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© 2017 IEEE. In this paper, a novel method is presented to optimize distributed generation (DG) in distribution networks. The suggested method shows how DGs should change their sizes and places, if it is necessary, to improve the voltage profile and total power loss of distribution networks. For this purpose, game theory is applied to model the optimization problem. At the first step, an appropriate game based on the Nash equilibrium is suggested. Using the specific features of game theory, the procedure of decision making in the operator centers of distribution grids is considered. Then, the optimization problem is solved by finding Nash equilibrium point. To solve the Nash equilibrium, a specific kind of genetic algorithm (GA) called Nash GA is applied.
Belotti, Y, Conneely, M, Huang, T, McKenna, S, Nabi, G & McGloin, D 1970, 'Microfluidics-based, time-resolved mechanical phenotyping of cells using high-speed imaging', SPIE Proceedings, European Conferences on Biomedical Optics, SPIE, Munich, GERMANY.
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Belotti, Y, Huang, T, McKenna, S, Nabi, G & McGloin, D 1970, 'High-throughput, imaging based mechanical phenotyping of prostate cancer cells', 2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 2017 Conference on Lasers and Electro-Optics Europe (CLEO/Europe) & European Quantum Electronics Conference (EQEC), IEEE, Munich, GERMANY.
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Bluff, A & Johnston, A 1970, 'Storytelling with Interactive Physical Theatre', Proceedings of the 4th International Conference on Movement Computing, MOCO '17: 4th International Conference on Movement Computing, ACM, London, United Kingdom, pp. 1-8.
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© 2017 ACM. This paper examines the way movement based interactive visuals were used as a storytelling device in the physical theatre production of Creature: Dot and the Kangaroo. A number of performers and artists involved in the production were interviewed and their perceptions of the interactive technology have been contrasted against a similar study into abstract dance. The animated backgrounds and interactive animal graphics projected onto the stage were found to reduce the density of script by describing the location of action and spirit of the character, reducing the necessity for this to be spoken. Peak moments of the show were identified by those interviewed and a scene analysis revealed that the most successful scenes featured a more integrated storytelling where the interaction between performers and the digital projections portrayed a key narrative message.
Bonthu, RK, Pham, H, Aguilera, RP & Ha, QP 1970, 'Minimization of building energy cost by optimally managing PV and battery energy storage systems', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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The combination of residential photovoltaic (PV) panels and battery energy storage system (BESS) is a promising solution in a building's microgrid. This paper presents an optimal energy management system (EMS) to minimize the electricity bill of residential buildings. The objective is to achieve peak shaving and electrical energy cost minimization for the owner, making use of a dynamic energy pricing model. Due to variability of PV generation and limitations of BESS, the optimization method should account for the utilisation of PV power generation and the conversion losses of power electronics converters. To deal with non-linearities involved, a particle swarm optimization (PSO) algorithm has been developed for minimization of the cost function. Simulation results show that the PSO-based EMS can achieve, as compared to standard schedule for a 24 hour period, a significant saving of daily electricity cost, which prompts for a suitable on-line control strategy
Braun, R & Chaczko, Z 1970, 'Using Matlab modeling in cody to teach Teletraffic engineering', 2017 16th International Conference on Information Technology Based Higher Education and Training (ITHET), 2017 16th International Conference on Information Technology Based Higher Education and Training (ITHET), IEEE, pp. 1-5.
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© 2017 IEEE. Engineering students are having to model increasingly complex constructed environments at the same time that their traditional mathematical skills are decreasing[?]. New approaches to modeling are needed. We started with the premise that students find mathematical modeling of Teletraffic problems challenging, and that this can be replaced through modeling in a 'computational' environment such as Matlab. In this paper, we show how the Teletraffic Engineering part of a Network Management subject can be made more interesting and accessible. We plot the student satisfaction scores to show the effectiveness of the approach.
Brookes, W 1970, 'Transdisciplinary learning in technology degrees', 2017 16th International Conference on Information Technology Based Higher Education and Training (ITHET), 2017 16th International Conference on Information Technology Based Higher Education and Training (ITHET), IEEE, Ohrid, Macedonia.
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This paper outlines a new kind of degree that has technology at its core, but is transdisciplinary in nature. Rather than students learning knowledge in discrete disciplinary blocks, they are exposed to ideas and practices from a wide variety of disciplines, and use these to create new ways of working that are underpinned by capabilities in computational thinking, complex systems, data and reasoning.
Cai, Y, Zhang, Y, Ding, C, Qian, Z & Liu, J 1970, 'Design of multilayer SIW cavity-backed slot antenna array', 2017 11th European Conference on Antennas and Propagation (EUCAP), 2017 11th European Conference on Antennas and Propagation (EUCAP), IEEE, Paris, France, pp. 1189-1193.
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© 2017 Euraap. In this paper, a multilayer substrate integrated waveguide (SIW) cavity-backed slot antenna array with wideband performance is proposed. In order to broaden the operating bandwidth of SIW slot antenna, multilayer cavities with gradually decreased permittivity and expanded aperture sizes are loaded above the slot, which realizes a smooth transition between SIW slot and free space. A wideband feeding network employing slot coupling is designed to excite the array elements. Results indicate the proposed array operates with 28.4% bandwidth ranging from 22.4 to 29.8 GHz. Besides, stable broadside radiation patterns are obtained across the operating band.
Candra, H, Yuwono, M, Chai, R, Nguyen, HT & Su, S 1970, 'EEG emotion recognition using reduced channel wavelet entropy and average wavelet coefficient features with normal Mutual Information method', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Jeju Island, Korea, pp. 463-466.
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© 2017 IEEE. Recognizing emotion from EEG signals is a complicated task that requires complex features and a substantial number of EEG channels. Simple algorithms to analyse the feature and reduce the EEG channel number will give an indispensable advantages. Therefore, this study explores a combination of wavelet entropy and average wavelet coefficient (WEAVE) as a potential EEG-emotion feature to classify valence and arousal emotions with the advantage of the ability to identify the occurrence of a pattern while at the same time identify the shape of a pattern in EEG emotion signal. The complexity of the feature was reduced using the Normalized Mutual Information (NMI) method to obtain a reduced number of channels. Classification with the WEAVE feature achieved 76.8% accuracy for valence and 74.3% for arousal emotion, respectively. The analysis with NMI shows that the WEAVE feature has linear characteristics and offers possibilities to reduce the EEG channels to a certain number. Further analysis also reveals that detection of valence emotion with reduced EEG channels has a different combination of EEG channels compared to arousal emotion.
Chaczko, Z & Braun, R 1970, 'Learning data engineering: Creating IoT apps using the node-RED and the RPI technologies', 2017 16th International Conference on Information Technology Based Higher Education and Training (ITHET), 2017 16th International Conference on Information Technology Based Higher Education and Training (ITHET), IEEE, Ohrid, Macedonia.
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© 2017 IEEE. This paper demonstrates the suitability and the practicality of using the advanced open source tools such as the Raspberry Pi and the Node-RED for teaching and learning in the Internet of Things (IOT) subject within a newly created major of Data Engineering in the Faculty of Engineering and IT at University of Technology, Sydney. Understanding and practicing of the Internet of Things largely depend on the high availability of tools, their low cost, and ease of use that can accelerate learning processes. This paper demonstrates relatively uncomplicated practical lab exercises involving the Raspberry Pi hardware, firmware and the Node-RED programming environment that students can execute to stimulate their learning, understanding of the Internet of Things technology and acquire fundamental data engineering skills.
Chaczko, Z, Jiang, F & Ahmed, B 1970, 'Road Vehicle Alert System Using IOT', 2017 25th International Conference on Systems Engineering (ICSEng), 2017 25th International Conference on Systems Engineering (ICSEng), IEEE, Las Vegas, NV, USA, pp. 488-496.
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© 2017 IEEE. The consequence of road accidents that involves a motorcycle is far more fatal for the rider than the other drivers. Yet, there has not been an effective vehicle alert system that can eliminate these avoidable motorcycle accidents caused by other drivers where they fail to notice the motorcycles. One of the major flaws with the existing vehicle alert systems is that it should not treat motorcycles as same as other vehicles as they take much longer time to brake than a cars do. Therefore, this project aimed to find an effective method to identify motorcycles and alert the other drivers when motorcyclists are around them in 20-meter radius. After extensive literature review, the best method to solve the problem is to use road side infrastructure based Internet of Things (IOT) that divides the network into a set of clusters. In this method to identify a vehicle, it is identifying the driver and the rider from their smartphone application that beacons custom, unique Media Access Control (MAC) addresses via Bluetooth or Wi-Fi to the IOT probes. The probe differentiates the users, registers them when they arrive into the network, alerts the driver about motorcycles around them and removes them from the database when they move to other cluster. The whole scenario is simulated using the OMNET++ simulator and INET framework to demonstrate how the methodology works. If the concept is implemented in real-life, many valuable lives of motorists will be much safer on the road.
Chai, R, Naik, GR, Ling, SH, Tran, Y, Craig, A & Nguyen, HT 1970, 'Channels selection using independent component analysis and scalp map projection for EEG-based driver fatigue classification', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Jeju Island, Korea, pp. 1808-1811.
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This paper presents a classification of driver
fatigue with electroencephalography (EEG) channels selection
analysis. The system employs independent component analysis
(ICA) with scalp map back projection to select the dominant of
EEG channels. After channel selection, the features of the
selected EEG channels were extracted based on power spectral
density (PSD), and then classified using a Bayesian neural
network. The results of the ICA decomposition with the backprojected
scalp map and a threshold showed that the EEG
channels can be reduced from 32 channels into 16 dominants
channels involved in fatigue assessment as chosen channels,
which included AF3, F3, FC1, FC5, T7, CP5, P3, O1, P4, P8,
CP6, T8, FC2, F8, AF4, FP2. The result of fatigue vs. alert
classification of the selected 16 channels yielded a sensitivity of
76.8%, specificity of 74.3% and an accuracy of 75.5%. Also,
the classification results of the selected 16 channels are
comparable to those using the original 32 channels. So, the
selected 16 channels is preferable for ergonomics improvement
of EEG-based fatigue classification system.
Chehrazad, S, Aghdasi, HS, Shariati, N & Abolhasan, M 1970, 'Addressing coverage problem in wireless sensor networks based on evolutionary algorithms', 2017 23rd Asia-Pacific Conference on Communications (APCC), 2017 23rd Asia-Pacific Conference on Communications (APCC), IEEE, Perth, WA, Australia.
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Wireless Sensor Networks (WSNs) are the key part of Internet of Things, as they provide the physical interface between on-field information and backbone analytic engines. An important role of WSNs-when collecting vital information-is to provide a consistent and reliable coverage. To Achieve this, WSNs must implement a highly reliable and efficient coverage recovery algorithm. In this paper, we take a fresh new approach to coverage recovery based on evolutionary algorithms. We propose EMACB-SA, which introduces a new evolutionary algorithm that selects coverage sets using a fitness function that balances energy efficiency and redundancy. The proposed algorithm improves network's coverage and lifetime in areas with heterogeneous event rate in comparison to previous works and hence, it is suitable for using in disaster management.
Chen, S-L, Qin, P-Y & Guo, YJ 1970, 'Multi-linear polarization reconfigurable center-fed circular patch antenna with shorting posts', 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, IEEE, San Diego, CA, USA, pp. 2209-2210.
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© 2017 IEEE. In this paper, a novel multi-linear polarization reconfigurable antenna with shorting posts, which can achieve four linear polarizations (0°, 45°, 90°, 135°), has been proposed. By switching the diodes between two groups of shorting posts, four linear polarizations can be realized. The dimensions of the proposed antenna are about 0.56λ× 0.56λ×0.07λ at 2.4 GHz. The measured results agree well with the simulated ones.
Chen, S-L, Qin, P-Y, Guo, YJ, Liu, Y & You, P 1970, 'Array pattern synthesis using numerical pattern synthesis algorithm including mutual coupling', 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, IEEE, San Diego, CA, USA, pp. 2295-2296.
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© 2017 IEEE. In this paper, numerical pattern synthesis (NPS) algorithm integrated with seeded region growing (SRG) method is proposed to synthesize the array in the presence of mutual coupling. In order to obtain the mutual coupling between the array elements, active pattern technique is used to find active element patterns. A 4 × 8 microstrip antenna array is employed to validate the effectiveness of the proposed algorithm including mutual coupling.
Chen, S-L, Qin, P-Y, Guo, YJ, Liu, Y & You, P 1970, 'Array Pattern Synthesis Using Numerical Pattern Synthesis Algorithm Including Mutual Coupling', 2017 IEEE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION & USNC/URSI NATIONAL RADIO SCIENCE MEETING, International Symposium of IEEE-Antennas-and-Propagation-Society / USNC/URSI National Radio Science Meeting, IEEE, San Diego, CA, pp. 2291-2292.
Chen, W-H, Liu, G, Su, SW, Jiang, Q & Nguyen, HT 1970, 'A CHF detection method based on deep learning with RR intervals.', EMBC, 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, IEEE, Seogwipo, South Korea, pp. 3369-3372.
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© 2017 IEEE. There are extensive studies investigating congestive heart failure (CHF) detection based on heart rate variability. Although a high level of accuracy has been achieved, its robustness under different conditions is not guaranteed. To improve the robustness, we applied sparse auto-encoder-based deep learning algorithm in CHF detection with RR intervals. A total data size of 30,592 (5-min RR interval) was obtained from 72 healthy persons and 44 CHF patients. The deep learning algorithm first extracts unsupervised features using a sparse auto-encoder from raw RR intervals, then constructs a deep neural network model with various hidden nodes combinations. Results showed that the model achieved 72.41% accuracy. This demonstrated that RR intervals have potential in CHF detection but cannot fully reflect dynamic change in 24-h.
Chen, X, Ni, W, Chen, T, Collings, IB, Wang, X, Liu, RP & Giannakis, GB 1970, 'Distributed Stochastic Optimization of Network Function Virtualization', GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017 IEEE Global Communications Conference (GLOBECOM 2017), IEEE, Singapore, Singapore, pp. 1-6.
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© 2017 IEEE. Decoupling network services from underlying hardware, network function virtualization (NFV) is expected to significantly improve agility and reduce network cost. However, network services, sequences of network functions, need to be processed in specific orders at specific types of virtual machines (VMs), which couples decisions of VMs on processing or routing network services. Built on a new stochastic dual gradient method, our approach suppresses the couplings, minimizes the time-average cost of NFV, stabilizes queues at VMs, and reduces the backlogs of unprocessed services through online learning and adaptation. Asymptotically optimal decisions are instantly generated at individual VMs, with a cost-delay tradeoff [(ϵ)/√ϵ]. Numerical results show that the proposed method is able to reduce the time-average cost of NFV by 30% and reduce the queue length (or delay) by 83%, as compared to existing non-stochastic approaches.
Chen, X, Wang, X, Ni, W & Collings, IB 1970, 'Two-way energy trading and online planning for fifth-generation communications with renewables', 2017 23rd Asia-Pacific Conference on Communications (APCC), 2017 23rd Asia-Pacific Conference on Communications (APCC), IEEE, Perth, WA, Australia, pp. 552-557.
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© 2017 University of Western Australia. Future fifth-generation (5G) cellular networks, equipped with energy harvesting devices, are uniquely positioned to closely interoperate with smart grid. New interoperable functionalities are discussed in stochastic two-way energy trading and online planning to improve efficiency and productivity. Challenges lie in the unavailability of a-priori knowledge on future wireless channels, energy pricing and harvesting. Lyapunov optimization techniques are utilized to address the challenges and stochastically optimize energy trading and planning. Particularly, it is able to decouple the optimization of energy trading and planning during individual time slots, hence eliminating the need for joint optimization across a large number of slots.
Cheng, L, Acuna, P, Aguilera, RP, Jiang, J, Flecther, J & Baier, C 1970, 'Model predictive control for Energy Management of a hybrid energy storage system in Light Rail Vehicles', 2017 11th IEEE International Conference on Compatibility, Power Electronics and Power Engineering (CPE-POWERENG), 2017 11th IEEE International Conference on Compatibility, Power Electronics and Power Engineering (CPE-POWERENG), IEEE, pp. 683-688.
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© 2017 IEEE. A model predictive control (MPC) for an onboard hybrid energy storage system (HESS) in Light Rail Vehicles is proposed. The HESS uses batteries and supercapacitors (SCs). The main objective of the controller is to reduce the system losses while maintaining the supercapacitors state-of-charge (SOC) in a suitable range. To do this, a hierarchical control (Master/Slave) is proposed: a master energy management MPC controller which generates the battery current reference and an slave MPC algorithm controls the power switches of the converters. Additionally, the capability to constraint the battery current reference and battery current is achieved by both controllers respectively. Simulation results, carried out in MATLAB/Simulink, show that the SC SOC is maintained in a suitable range.
Cheng, P, Chen, Z, Zhang, JA, Li, Y & Vucetic, B 1970, 'Low-Complexity Precoding for Spatial Modulation', 2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), IEEE, Toronto, ON, Canada, pp. 1-5.
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© 2017 IEEE. In this paper, we investigate linear precoding for spatial modulation (SM) over multiple-input-multiple-output (MIMO) fading channels. With channel state information available at the transmitter, our focus is to maximize the minimum Euclidean distance among all candidates of SM symbols. We prove that the precoder design is a large-scale non-convex quadratically constrained quadratic program (QCQP) problem. However, the conventional methods, such as semi-definite relaxation and iterative concave-convex process, cannot tackle this challenging problem effectively or efficiently. To address this issue, we leverage augmented Lagrangian and dual ascent techniques, and transform the original large-scale non-convex QCQP problem into a sequence of subproblems. These subproblems can be solved in an iterative manner efficiently. Numerical results show that the proposed method can significantly improve the system error performance relative to the SM without precoding, and features extremely fast convergence rate with very low computational complexity.
Cheng, Q, Nguyen, DN, Dutkiewicz, E & Mueck, MD 1970, 'Preserving operational information in spectrum access system with dishonest users', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, QLD, Australia, pp. 1-6.
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© 2017 IEEE. Privacy has been regarded as one of the most critical issues in light of promoting the development of centralized spectrum management, hence attracting wide attention. However, researchers in the current literature are usually protecting users' privacy based on the assumption that all users are honest, which is reasonable but not practical. In this paper, we investigate the privacy issue among different tiers of users in the centralized spectrum access system (SAS), mainly focusing on honest Priority Access Licenses (PALs) and dishonest General Authorized Accesses (GAAs). To that end, we propose an authentication scheme to prevent GAAs from using other users' information by the aid of a public key cryptosystem. Moreover, we propose a 'punishment and forgiveness' scheme, which draws support from GAAs' reputation stores (RSs) and reputation histories (RHs), to encourage GAAs to engage in positive and true activities. Besides, we propose a privacy preservation scheme cooperating with the 'punishment and forgiveness' scheme (PS-PFS) in order to effectively mitigate the impact of dishonest users while fully preserving all users' privacy as well as successfully realizing spectrum sharing.
Chiu, C, Chaczko, Z & Yu, Z 1970, 'Assessment of a Multi-Agent RFID Platform for Industrial Logistic Operations', 5th Asia-Pacific Conference on Computer-Aided System Engineering, 5th Asia-Pacific Conference on Computer-Aided System Engineering, APCASE Foundation, Guilin, Guangxi, China.
Chub, A, Siwakoti, Y, Vinnikov, D & Blaabjerg, F 1970, 'Sheppard-Taylor isolated high boost DC-DC converter', 2017 IEEE Applied Power Electronics Conference and Exposition (APEC), 2017 IEEE Applied Power Electronics Conference and Exposition (APEC), IEEE, pp. 1695-1699.
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© 2017 IEEE. This paper presents a new galvanically isolated step-up dc-dc converter intended for low-power but high step-up applications. The proposed converter is capable of regulating output voltage within a wide range of the input voltage or load variations. In contrast to competitors, the converter can be implemented with fewer passive components. Soft-switching in semiconductors allows achieving high efficiency. In addition, the input side current is continuous. The operating principle and the design guidelines derived for the converter are presented. Theoretical results are supported with experimental results obtained using a 100 W prototype. The converter proposed can be used in photovoltaic module level power electronics applications, where a wide input voltage and load regulation range are highly demanded.
Cong, HP, Perry, S, Vu, TA & HoangVan, X 1970, 'Joint exploration model based light field image coding: A comparative study', 2017 4th NAFOSTED Conference on Information and Computer Science, 2017 4th NAFOSTED Conference on Information and Computer Science, IEEE, Hanoi, Vietnam, pp. 308-313.
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The recent light field imaging technology has been attracting a lot of interests due to its potential applications in a large number of areas including Virtual Reality, Augmented Reality (VR/AR), Teleconferencing, and E-learning. Light Field (LF) data is able to provide rich visual information such as scene rendering with changes in depth of field, viewpoint, and focal length. However, Light Field data usually associates to a critical problem — the massive data. Therefore, compressing LF data is one of the main challenges in LF research. In this context, we present in this paper a comparative study for compressing LF data with not only the widely used image/video coding standards, such as JPEG-2000, H.264/AVC, HEVC and Google/VP9 but also with the most recent image/video coding solution, the Joint Exploration Model. In addition, this paper also proposes a LF image coding flow, which can be used as a benchmark for future LF compression evaluation. Finally, the compression efficiency of these coding solutions is thoroughly compared throughout a rich set of test conditions.
Dang, DNM, Ngo, QT, Dang, HN, Vo, PL & Hong, CS 1970, 'Directional Multi-channel MAC for VANETs', Springer International Publishing, pp. 803-812.
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Dang, TD & Hoang, D 1970, 'A data protection model for fog computing', 2017 Second International Conference on Fog and Mobile Edge Computing (FMEC), 2017 Second International Conference on Fog and Mobile Edge Computing (FMEC), IEEE, Valencia, SPAIN, pp. 32-38.
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Davis, QT, Tanaka, T & McGloin, D 1970, 'Transport of intensity microscopy for distinguishing single and bundled microtubules', 2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), 2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), IEEE, Munich, Germany.
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Microtubules are filamentous protein polymers about 25 nm in diameter, ubiquitous in eukaryotes and providing key functionality in cellular biology. Although microtubules may span many microns in length, their slender width places them well below the diffraction limit. Unlabeled microtubules lack any meaningful absorption of a passing wavefront, and are therefore sub-resolution phase objects.
Ding, C, Jones, B, Sun, H, Qin, P-Y, Guo, YJ & Ji, L 1970, 'Wideband feeding method for full-wave dipole', 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, IEEE, San Diego, CA, USA, pp. 2131-2132.
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© 2017 IEEE. This paper introduces a wide-band feeding method for full-wave dipole antennas. A full-wave dipole is designed to cover the band from 698 MHz to 960 MHz for cellular base station applications. Its matching circuit consists of a laddertype filter design and a quasi-quarter-wavelength resistance transformer. The proposed matching circuit can provide balanced feeding as a balun and has a compact size. The matching circuit is designed and optimized using a circuit theory model and then physically realized using microstrip lines based on full-wave simulation. The simulated reflection coefficient |S11| is < -15 dB across the entire target band, exhibiting a bandwidth of 32%.
Dong, L, Niyato, D, Kim, DI & Hoang, DT 1970, 'A Joint Scheduling and Content Caching Scheme for Energy Harvesting Access Points with Multicast', GLOBECOM 2017 - 2017 IEEE Global Communications Conference, GLOBECOM 2017 - 2017 IEEE Global Communications Conference, IEEE, Singapore, Singapore, pp. 1-6.
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© 2017 IEEE. In this work, we investigate a system where users are served by an access point that is equipped with energy harvesting and caching mechanism. Focusing on the design of an efficient content delivery scheduling, we propose a joint scheduling and caching scheme. The scheduling problem is formulated as a Markov decision process and solved by an on-line learning algorithm. To deal with large state space, we apply the linear approximation method to the state-Action value functions, which significantly reduces the memory space for storing the function values. In addition, the preference learning is incorporated to speed up the convergence when dealing with the requests from users that have obvious content preferences. Simulation results confirm that the proposed scheme outperforms the baseline scheme in terms of convergence and system throughput, especially when the personal preference is concentrated to one or two contents.
Dutkiewicz, E, He, Y, Jayawickrama, BA & Abeywickrama, HV 1970, 'Radio environment maps generation and spectrum sensing testbed for spectrum sharing in 5G networks', 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Verona, ITALY, pp. 33-36.
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© 2017 IEEE. To deliver on the data rate and latency promises of 5G, more spectrum resources below 6 GHz are required. Therefore the regulators are now promoting spectrum sharing. Having access to realtime spatio-Temporal spectrum usage information enables efficient decision making and monitoring. This knowledge can be represented in Radio Environment Maps constructed through geolocation aware spectrum measurements. In this paper, we give an overview of the spectrum sharing concept and its emergence in 5G standardisation. We also present our research on spectrum sharing including methods for efficient and accurate generation of Radio Environment Maps and a practical radio spectrum measurements testbed.
Dutkiewicz, E, Jayawickrama, BA & He, Y 1970, 'Radio spectrum maps for emerging IoT and 5G networks: Applications to smart buildings', 2017 International Conference on Electrical Engineering and Computer Science (ICECOS), 2017 International Conference on Electrical Engineering and Computer Science (ICECOS), IEEE, Palembang, Indonesia, pp. 7-9.
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© 2017 IEEE. The high demand for wireless Internet including emerging Internet of Things (IoT) applications is putting extreme pressure on better utilisation of the available radio spectrum. The expected spectrum 'crunch' requires highly efficient radio resource management schemes with low complexity and high responsiveness to the changing network conditions. Spectrum sharing is regarded as an essential approach to regaining access to otherwise unused spectrum and it is considered an essential component in the development of IoT and 5G networks. Spectrum sharing can be conducted at different time scales. As the time scale of the operation of spectrum sharing decreases, the possibility for utilising more available spectrum holes increases. However, the shorter time scale brings with it challenges. Efficient decisions regarding the use of spectrum sharing require accurate knowledge of the spatial and temporal spectrum use in a geographical area of interest. This knowledge can be represented in Radio Spectrum Maps which need to be generated efficiently and accurately. In this paper we give an overview of the spectrum sharing concept for IoT and 5G networks. We also present our research on spectrum sharing to enable Smart Building IoT applications.
Eskandari, M & Li, L 1970, 'A novel small signal model of multi-bus microgrids for modeling interaction of droop controllers through the power network', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, pp. 1-6.
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© 2017 IEEE. Microgrid (MG) consists of distributed generation (DG) units, which supply MG loads via the power network. Droop-based control system has been proposed for power sharing implementation among DG units in MGs. The droop control performance is based on the power network variables, which makes it easy to implement. As the control system at the primary level, the droop controller plays a major role in secure operation of MGs in terms of stability concern. However, the lack of high band-width communication links, low X/R ratio of grid impedance and fast response power converters make the droop-based MGs exposed to instability. In this work, a suitable small signal model is developed to assess the droop control system performance and stability. In the proposed model, droop controllers' interaction through the transmission network is modeled appropriately. The proposed model reveals unstable regions which have not been discovered by the conventional parallel-based small signal models.
Esselle, KP 1970, 'Leaky-wave antennas: From niche applications to mass market', 2017 IEEE Radio and Antenna Days of the Indian Ocean (RADIO), 2017 IEEE Radio and Antenna Days of the Indian Ocean (RADIO), IEEE.
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Every, J, Li, L & Dorrell, DG 1970, 'Economic optimization of hybrid PV-battery systems using hourly satellite insolation and daily temperature data: A case study', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, pp. 1-6.
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© 2017 IEEE. This paper presents an economic optimization case study for a medium-scale hybrid PV-battery system. PV energy yield and battery operation models based on hourly satellite insolation and daily temperature data form the basis of an underlying objective function aiming to maximize the net present value of potential energy cost savings. Forecasted system prices and energy tariffs over a nine-year period are considered enabling the opportune year to invest and the characteristics of the corresponding optimal system to be determined.
Every, J, Li, L & Dorrell, DG 1970, 'Optimal selection of small-scale hybrid PV-battery systems to maximize economic benefit based on temporal load data', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 471-476.
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© 2017 IEEE. Continued advances in PV and battery energy storage technologies have made hybrid PV-battery systems an attractive prospect for residential energy consumers. However the process to select an appropriate system is complicated by the relatively high cost of batteries, a multitude of available retail electricity plans and the removal of PV installation incentive schemes. In this paper, an optimization strategy based on an individual customer's temporal load profile is established to maximize electricity cost savings through optimal selection of PV-battery system size, orientation and retail electricity plan. Quantum-behaved particle swarm optimization is applied as the underlying algorithm given its well-suited application to problems involving hybrid energy system specification. The optimization strategy is tested using real-world residential consumption data, current system pricing and available retail electricity plans to establish the efficacy of a hybrid PV-battery solution.
Fang, L, Li, H, David Huang, D & Huang, X 1970, 'A low cost interpolation based detection algorithm for medium-size massive MIMO-OFDM systems', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, Australia, pp. 1-5.
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© 2017 IEEE. The great potential of exploiting millimeter wave (mmwave) frequency spectrum for emerging fifth-generation (5G) wireless networks has motivated the study of massive multiple-input multiple-output (MIMO) for achieving high data rate. For medium-size massive MIMO with orthogonal frequency division multiplexing (OFDM) uplink systems, the minimum mean square error (MMSE) based soft-output detector is often used due to its better bit error rate (BER) performance compared to the matched filter detector. Although the multipath channel can be converted into a set of parallel flat-fading channels by using OFDM thus reducing the complexity of receiver design, the tone by tone (per subcarrier) detection methods based on the state-of-The-Art low complexity MMSE still incur considerably high computational complexity since the number of tones is typically very large. To reduce the complexity, the interpolation-based matrix inversion algorithms for small-size MIMO-OFDM systems have been proposed, which compute the matrix inversion by interpolating separately the adjoint and determinant. In this paper, we find that the (regularized) Gram matrix inversions have strong correlation between different subcarriers. By exploiting this strong correlation, we propose a linear interpolation based MMSE detection algorithm that directly interpolates the inverted MMSE matrices for a small number of subcarriers to obtain matrix inversions for all other subcarriers, thereby significantly reducing the number of matrix inversion required. Extensive simulations show that with small BER performance loss compared to the exact MMSE detector, the proposed algorithm can reduce the complexity to the level of the matched filter algorithm.
Farahmandian, S & Hoang, DB 1970, 'SDS<inf>2</inf>: A novel software-defined security service for protecting cloud computing infrastructure', 2017 IEEE 16th International Symposium on Network Computing and Applications (NCA), 2017 IEEE 16th International Symposium on Network Computing and Applications (NCA), IEEE, Cambridge, MA, USA, pp. 1-8.
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© 2017 IEEE. Software-Defined Infrastructure (SDI) is a resource sharing infrastructure that embraces the concept of separation of the network control plane from its data plane, and software realization of network functions from the underlying hardware appliances through the virtualization technology in emerging infrastructures such as Cloud, Network Function Virtualization (NFV), and Software-Defined Networking (SDN). Virtualization and virtualized infrastructures bring with them new challenges regarding security and virtual resources protection. Traditional security measures and endpoint security are no longer adequate due to invisible boundaries created among shared logical and virtual entities among numerous users. This paper introduces a software-defined security service (SDS2) for protecting cloud infrastructures. SDS2focuses on defining security concerns regarding physical and virtual boundaries of data, resources, tenants and detecting security breaches through violations of boundaries. Boundaries are defined by security policies and security violations by attackers are predicted, monitored, and detected when boundaries are crossed. This paper describes SDS2and presents its initial implementation. The paper provides examples of policy-defined boundaries and shows the effectiveness and feasibility of our design in detecting invisible security boundaries through simulation of a security control structure and agile, dynamic, and intelligent VSFs.
Farahmandian, S & Hoang, DB 1970, 'SDS2: A Novel Software-Defined Security Service for Protecting Cloud Computing Infrastructure', The 16th IEEE International Symposium on Network Computing and Applications17), The 16th IEEE International Symposium on Network Computing and Applications17), Cambridge, MA, USA.
Farhood, H, He, X, Jia, W, Blumenstein, M & Li, H 1970, 'Counting People Based on Linear, Weighted, and Local Random Forests', 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), IEEE, Sydney, pp. 1-7.
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© 2017 IEEE. Recently, many works have been published for counting people. However, when being applied to real-world train station videos, they have exposed many limitations due to problems such as low resolution, heavy occlusion, various density levels and perspective distortions. In this paper, following the recent trend of regression-based density estimation, we present a linear regression approach based on local Random Forests for counting either standing or moving people on station platforms. By dividing each frame into sub-windows and extracting features with ground truth densities as well as learned weights, we perform a linear transformation for counting people to overcome the perspective problems of the existing patch-based approaches. We present improvements against several recent baselines on the UCSD dataset and a dataset of CCTV videos taken from a train station. We also show improvements in speed compared with the state-of-the-art models based on detection and Deep Learning.
Farrok, O, Islam, MR, Sheikh, MRI, Guo, Y, Zhu, J & Lei, G 1970, 'A novel method to avoid degradation due to demagnetization of PM linear generators for oceanic wave energy extraction', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, AUSTRALIA.
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© 2017 IEEE. Demagnetization is one of the noticeable problems in almost every permanent magnet linear generator (PMLG) for oceanic wave energy conversion. To avoid the degradation of electrical power generation capability, a PMLG with a new feature of variable air gap length is proposed in this paper. To verify the effectiveness of the proposed method, a PMLG has been designed which is simulated for both the fixed and variable air gaps. The finite element analysis is performed for simulation for analysis of the PMLG with the conventional and the proposed methods by using the software package ANSYS/Ansoft. The voltage, current, power, magnetic flux density, and force components of the PMLG are analyzed and discussed. The simulation results show that the new method can effectively avoid the demagnetization problem.
Fernandez, E, Jamborsalamati, P, Hossain, MJ & Amin, U 1970, 'A communication-enhanced price-based control scheme for HVAC systems', 2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), 2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), IEEE, pp. 1-6.
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© 2017 IEEE. Real-time electricity pricing has been a key issue in Australia's national electricity markets. The average electricity bill paid by a consumer is influenced by the amount of energy consumption by different loads and their time of use. Certain loads such as dishwashers and pool pumps are deferrable while loads such as lighting and refrigeration are non-deferable. HVAC (heating, ventilation and air conditioning) systems contribute to a major part of the energy consumption of a building. This paper discusses the design of real-time energy pricing in a transactive environment where the key players will be the consumers. The designed real-time control scheme in this paper is to define the final thermostat set-point for each HVAC based on the bidding price. In addition, this paper proposes the communication architecture to implement the designed control scheme through two-way communication between HVACs, data aggregator and the central controller. The proposed architecture utilizes the Message Queue Telemetry Transport (MQTT) protocol which is the state-of-the-art lightweight messaging protocol for use on top of the TCP/IP protocol. From the analysis, it is evident that the proposed algorithm enables customers to reduce energy costs and increases energy efficiency.
Forouzesh, M, Shen, Y, Yari, K, Siwakoti, Y, Blaabjerg, F & Wang, H 1970, 'A new soft-switched high step-up DC-DC converter with dual coupled inductors', 2017 IEEE 12th International Conference on Power Electronics and Drive Systems (PEDS), 2017 IEEE 12th International Conference on Power Electronics and Drive Systems (PEDS), IEEE, Honolulu, HI, USA, pp. 863-868.
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© 2017 IEEE. This paper introduces a new efficient high step-up DC-DC converter with a shared input path and dual series coupled inductors at the output. This converter is suitable for high power applications due to its shared input current that puts low current stresses on the low voltage side switches. The proposed converter uses active clamp circuits with a shared clamp capacitor for main switches. In addition to the active clamp circuit, the leakage energy is recycled to the output by the act of an integrated regenerative snubber. Both active and passive switching devices operate with soft-switching performance i.e. Zero Voltage Switching (ZVS) and Zero Current Switching (ZCS). Principle of operation and mathematical derivation are presented and verified through simulation and experimental results of a 1kW prototype.
Gadalla, B, Schaltz, E, Siwakoti, Y & Blaabjerg, F 1970, 'Loss distribution and thermal behaviour of the Y-source converter for a wide power and voltage range', 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia (IFEEC 2017 - ECCE Asia), 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia (IFEEC 2017 - ECCE Asia), IEEE, Kaohsiung, Taiwan, pp. 878-883.
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© 2017 IEEE. The Y-source converter is one of the recent proposed impedance source converters. It has some advantages as having a high voltage gain between the input and output voltage sides using very small duty cycle ratios. For many applications, the input voltage needs to be boosted to higher output voltage, such as for fuel cell, battery electric vehicles and renewable energy applications. Understanding the loss distribution and thermal performance is very important in order to be able to design a reliable converter with longer lifetime. In this paper, the loss distribution of a Y-source converter for a wide voltage and power range is presented. The influence of the heat losses generated in the converter is also considered for different analysis. A simulation model is developed and verified experimentally rated at 300 W.
Gao, X, Du, J, Zhang, T & Guo, YJ 1970, 'Design of a monolithic-integrated circularly-polarized antenna-coupled high-T<inf>c</inf> superconducting terahertz harmonic mixer', 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Verona, ITALY, pp. 324-325.
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Gautam, S, Lu, DD-C, Lu, Y & Xiao, W 1970, 'Fast identification of active and reactive current component for single phase grid interconnection', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. Single phase grid connected converters in Photo-voltaic(PV) and Electric Vehicles(EV) are finding their application in reactive power support to grid. A power feedback is generally integrated in the control loop for this purpose. Fast and accurate calculation of active and reactive power of the converter is necessary for swift response of controller in regulating output power. This also prevents converter from being overloaded. This paper presents a fast and simple technique to measure the active and reactive power component utilizing wave-shape similarity of sine and cosine function. The performance of the proposed method is compared with dq transformation based approach. The discussions and simulations show superiority of the proposed method in dynamics and implementation.
Ghavidel, S, Azizivahed, A, Barani, M, Aghaei, J, Li, L & Zhang, J 1970, 'Static Var Compensator allocation considering transient stability, voltage profile and losses', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia, pp. 1-6.
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© 2017 IEEE. The purpose of this paper is to determine the optimal location, size and controller parameters of Static Var Compensator (SVC) to simultaneously improve static and dynamic objectives in a power system. Four goals are considered in this paper including transient stability, voltage profile, SVC investment cost and power loss reduction. Along with the SVC allocation for improving the system transient stability, an additional controller is used and adjusted to improve the SVC performance. Also, an estimated annual load profile including three load levels is utilized to accurately find the optimal location and capacity of SVC. By considering three load levels, the cost of power losses in the power system is decreased significantly. The combination of the active power loss cost and SVC investment cost is considered as a single objective to obtain an accurate and practical solution, while the improvement of transient stability and voltage profile of the system are considered as two separate objectives. The problem is therefore formulated as a multi-objective optimization problem, and Multi Objective Particle Swarm Optimization (MOPSO) algorithm is utilized to find the best solutions. The suggested technique is verified on a 10-generator 39-bus New England test system. The results of the nonlinear simulation indicate that the optimal sizing, location and controller parameters setting of SVC can improve significantly both static and dynamic performance of the system.
Ghavidel, S, Barani, M, Azizivahed, A, Ghadi, MJ, Li, L & Zhang, J 1970, 'Hybrid power plant offering strategy to deal with the stochastic nature and outage of wind generators', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia, pp. 1-6.
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© 2017 IEEE. The stochastic nature of wind power generators and their possible outage are crucial issues which make them difficult to participate in electricity markets. However, demand side as a decent balancing resource can be used to compensate the challenges of lack of supply-demand balance or state of outage for wind generators. This paper firstly models the outage of wind generators. Then an offering strategy with a three-stage stochastic programming is presented for a hybrid power plant which includes a wind power producer and a demand response provider. Three electricity markets are considered including day-ahead, adjustment and balancing market. The conditional value-at-risk is also added to the offering strategy to control the profit risk. The offering strategy is tested in a wind farm and electricity market located in Spain. The result shows that the hybrid power plant offering strategy can effectively assist with the balancing and outage problem of the wind power producer and increase the overall profit of the joint operation.
Ghavidel, S, Ghadi, MJ, Azizivahed, A, Barani, M, Aghaei, J, Li, L & Zhang, J 1970, 'Hybrid power plant bidding strategy including a commercial compressed air energy storage aggregator and a wind power producer', 2017 Australasian Universities Power Engineering Conference (AUPEC), 2017 Australasian Universities Power Engineering Conference (AUPEC), IEEE, Melbourne, AUSTRALIA, pp. 1-6.
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© 2017 IEEE. In this paper, a commercial compressed air energy storage (CAES) aggregator equipped with a simple cycle mode operation having the ability to work like a gas turbine is coordinated with a wind power aggregator (WPA) as a hybrid power plant to participate in electricity markets. In the proposed approach, the WPA uses the CAES to tackle its stochastic input and uncertainties related to different electricity market prices, and CAES can also use WPA to manage its charging/discharging and simple cycle modes more economically. A three-stage stochastic decision-making method is used to model the mentioned optimization problem which considers three electricity markets including day-ahead, intraday and balancing markets. The problem is formulated as a mixed integer linear programming which can be solved with available commercial solvers. Also, conditional value-at-risk is added to the problem to control the financial risk of the problem and offer different operation strategies for different financials risk levels. The proposed method can provide both bidding quantity and bidding curves to be submitted to the electricity markets which is tested on a realistic case study based on a wind farm and electricity market located in Spain. The results confirm that the proposed method can provide extra profit in joint operation, have more flexibility and reduce the financial risks.
Giampietro, C, Chaczko, Z, De La Villefromoy, M & Braun, R 1970, 'A new strategy for higher education and training: Peer support system for practical laboratories', 2017 16th International Conference on Information Technology Based Higher Education and Training (ITHET), 2017 16th International Conference on Information Technology Based Higher Education and Training (ITHET), IEEE, Ohrid, Macedonia, pp. 3-6.
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© 2017 IEEE. One of the many challenges facing practical student workshops is the proliferation of rapid prototyping and similar technologies. 3D printers have enabled students to take ideas and concepts further than ever before and sometimes to completion. The only limitations at this stage are the materials available for the manufacture of components and prototypes on 3D printers. Traditional manufacturing processes like fabrication and machining are still sometimes required to complete projects. This has seen a greater demand and workload for traditional machine shops and trades people. Some of the manufacturing work has to still be completed by skilled experienced trade's people but some of the simpler less complex machining and fabrication tasks could be easily completed by unskilled students with basic training and minimal supervision. We needed to come up with a system that provided students access to industrial fabrication and machining equipment in a safe and productive environment. The peer support system provides a framework enabling students with little or no machine operating skills to safely access industrial equipment with minimal staff, supervision and danger of injury. This paper is a justification of these concepts, interest, approaches, and practices of the peers support framework and philosophy.
Gordon, LC & Chaczko, Z 1970, 'Ontological Metamodel for Consistency of Data Heritage Preservation (DHP)', 2017 25th International Conference on Systems Engineering (ICSEng), 2017 25th International Conference on Systems Engineering (ICSEng), IEEE, Las Vegas, NV, USA, pp. 438-442.
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© 2017 IEEE. In this stage of Data Preservation the challenge is how to keep the attributes of the data and how to preserve the originality. It is like to keep the living part of the data. It is how the concepts of Heritage have sense. Heritage is the concrete data, it gives the interconnection to other aspects of the reality. Nowadays the physical value and the aspects of items complete the relevance of information. The relation between Preservation and Digital patterns of Heritage is well related because of the two aspects to consider: Accessibility and Context.
Gorji, SA, Mostaan, A, Ektesabi, M & Lu, D 1970, 'A novel bridgeless flyback power factor correction rectifier with single output winding and reduced components voltage stress', 2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe), 2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe), IEEE, Warsaw, Poland, pp. 1-9.
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© 2017 Assigned jointly to the European Power Electronics and Drives Association & the Institute of Electrical and Electronics Engineers (IEEE). In this paper, a novel bridgeless Flyback power factor correction rectifier is presented. Two active power switches, rather than the line-voltage diode bridge, are used to provide the bidirectional power flow. In comparison with the existing Flyback rectifiers, the proposed topology uses less number of transformer windings which simplifies the complexity of implementation in terms of magnetic utilization. Besides, the voltage stress on the output diodes and capacitors is reduced. After carrying out a detailed theoretical analysis, performance of the proposed converter was verified by simulations and experiments. The experimental tests on a 110 V to 48 V, 50W prototype reveal that an average efficiency at 90% and a high power factor can be achieved.
Gu, S, Lu, Y, Zhang, L & Zhang, J 1970, 'RGB-D Tracking Based on Kernelized Correlation Filter with Deep Features', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), International Conference on Neural Information ProcessingConference on Neural Information Processingtional Conference on Neural Information Processing, Springer International Publishing, Guangzhou, China, pp. 105-113.
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© 2017, Springer International Publishing AG. This paper proposes a new RGB-D tracker which is upon Kernelized Correlation Filter(KCF) with deep features. KCF is a high-speed target tracker. However, the HOG feature used in KCF shows some weaknesses, such as not robust to noise. Therefore, we consider using RGB-D deep features in KCF, which refer to deep features of RGB and depth images and the deep features contain abundant and discriminated information for tracking. The mixture of deep features highly improves the performance of the tracker. Besides, KCF is sensitive to scale variations while depth images benefit for handling this problem. According to the principle of similar triangle, the ratio of scale variation can be observed simply. Tested over Princeton RGB-D Tracking Benchmark, Our RGB-D tracker achieves the highest accuracy when no occlusion happens. Meanwhile, we keep the high-speed tracking even if deep features are calculated during tracking and the average speed is 10 FPS.
Guan, D, Ding, C & Guo, YJ 1970, 'A compact multi-beam antenna without beam forming network', ISAP 2016 - International Symposium on Antennas and Propagation, International Symposium on Antennas and Propagation (ISAP), IEEE, Okinawa, Japan, pp. 404-405.
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A novel approach to design a multi-beam array antenna without a beam forming network (BFN) is presented. The proposed antenna consists of 3×3 microstrip patches that are tightly coupled through microstrip lines. By exciting any one of these patches, the energy can be coupled to all the patches. Nine beams towards different directions are obtained by selecting different feeding ports. The resultant gain varies from 10 dBi to 11 dBi. The scanning ranges of the beams are ±24° and ±45° in the elevation and horizontal directions, respectively. The proposed antenna has a single-layered structure without complex feeding network, which significantly lowers its cost.
Gunawardane, K, Xie, S & Kularatna, N 1970, 'Back-to-back MOSFET switches to reduce the losses in SCALDO implementation', 2017 IEEE International Conference on Industrial Technology (ICIT), 2017 IEEE International Conference on Industrial Technology (ICIT), IEEE.
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Guo, J, Yuan, J & Zhang, JA 1970, 'Wireless Device-to-Device Caching Networks with Distributed MIMO and Hierarchical Cooperations', GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017 IEEE Global Communications Conference (GLOBECOM 2017), IEEE, Singapore, Singapore, pp. 1-6.
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© 2017 IEEE. In this paper, we propose a new caching scheme for a random wireless device-to-device (D2D) network of n nodes with local caches, where each node intends to download files from a prefixed library via D2D links. Our proposed caching delivery includes two stages, employing distributed MIMO and hierarchical cooperations respectively. The distributed MIMO is applied to the first stage between source nodes and neighbours of the destination node. The induced multiplexing gain and diversity gain increase the number of simultaneous transmissions, improving the throughput of the network. The hierarchical cooperations are applied to the second stage to facilitate the transmissions between the destination node and its neighbours. The two stages together exploit spatial degrees of freedom as well as spatial reuse. We develop an uncoded random caching placement strategy to serve this cooperative caching delivery. Analytical results show that the average aggregate throughput of the network scales almost linearly with n, with a vanishing outage probability.
Guo, K, Candra, H, Yu, H, Li, H, Nguyen, HT & Su, SW 1970, 'EEG-based emotion classification using innovative features and combined SVM and HMM classifier', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Jeju Island, Korea, pp. 489-492.
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Emotion classification is one of the state-of-theart
topics in biomedical signal research, and yet a significant
portion remains unknown. This paper offers a novel approach
with a combined classifier to recognise human emotion states
based on electroencephalogram (EEG) signal. The objective is
to achieve high accuracy using the combined classifier designed,
which categorises the extracted features calculated from time
domain features and Discrete Wavelet Transform (DWT). Two
innovative designs are involved in this project: a novel variable
is established as a new feature and a combined SVM and
HMM classifier is developed. The result shows that the joined
features raise the accuracy by 5% on valence axis and 1.5% on
arousal axis. The combined classifier can improve the accuracy
by 3% comparing with SVM classifier. One of the important
applications for high accuracy emotion classification system is
offering a powerful tool for psychologists to diagnose emotion
related mental diseases and the system developed in this project
has the potential to serve such purpose.
Guo, YJ & Qin, P-Y 1970, 'Single-layer reflectarrays — Past, present and future', 2017 11th European Conference on Antennas and Propagation (EUCAP), 2017 11th European Conference on Antennas and Propagation (EUCAP), IEEE, Paris, France, France, pp. 92-94.
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© 2017 IEEE. This paper presents an overview of the advances in single layer reflectarrays. In particular, it reports the progress in wideband reflectarrays and reconfigurable reflectarrays.
Ha, TV & Hoang, DB 1970, 'An assistive healthcare platform for both social and service networking for engaging elderly people', 2017 23rd Asia-Pacific Conference on Communications (APCC), 2017 23rd Asia-Pacific Conference on Communications (APCC), IEEE, Perth, Australia, pp. 1-6.
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Most countries around the globe are facing the same issue - an aging population. As an individual move from their working life to a retirement life, multiple socio-economic issues can occur as their social life has also significantly changed. This shift often affects an individual's mental health and well-being. As a result, the aging population requires a solution that does reduce not only its impact on the government but also harvests its contribution to the society. Existing solutions are based on utilizing online platforms such as social network or service network as a medium to reduce social isolation and improve the mental health of elderly people. However, these solutions fail on two accounts: 1) they fail to see older people as active contributors and 2) older people do not see the needs or benefits of using them. This paper proposes a solution that addresses those two issues by engaging people actively and collaboratively as contributors of services and/or receivers of social benefits through an assistive platform that integrates a service network with a social network. This model combines the advantages of both platforms, offers many opportunities for seniors to not only utilize their skills and knowledge to exchange benefits with other users but also expand their social life. The proposed model can be used as a mean to engage older adults to the community, making them become more active, improve their mental well-being and subsequently reduce the cost of health services to the society.
Haider, N, Dutkiewicz, E, Nguyen, DN, Mueck, M & Srikanteswarae, S 1970, 'The Impact on Full Duplex D2D Communication of Different LTE Transmission Techniques', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. To augment capacity of spectrum limited cellular systems, 3GPP proposed Licensed Assisted Access (LAA-LTE) while efforts are underway to standardize the standalone MulteFire (a small cell standalone version of LTE). LAA is expected to boost capacity of LTE via unlicensed spectrum (5GHz). On the other hand, recent advances in Self Interference Suppression (SIS) techniques allow radios to transmit and receive simultaneously on the same channel (i.e., in-band Full-Duplex, FD). As part of future wireless networks, Device-to-device (D2D) communications would find its great potential through this FD capability. However, due to high induced aggregate interference from FD and its impact on medium access probability, the rigorous and critical analysis is needed to find an optimum trade-off between performance efficiency and overheads. Using stochastic geometry and the random graph theory, in this article, we analyze the impact of different LTE network paradigms with HD/FD D2D devices. Moreover, the impact of state- of-the-art coexistence techniques (discontinuous transmission and listen-before-talk) recommended for LTE in unlicensed spectrum over HD/FD D2D network is also discussed. The analysis is supported with extensive simulation results that reveal insights of the coexistence mechanism efficiency employed by LTE, the impact of SIS and the cost of FD operation in D2D.
Hashmi, RM & Esselle, KP 1970, 'Aperture field transformation in resonant cavity antennas by transverse permittivity gradient superstrates', 2017 XXXIInd General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS), 2017 XXXIInd General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS), IEEE, pp. 1-3.
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© 2017 URSI. Single-feed resonant cavity antennas (RCAs) with transverse permittivity gradient (TPG) superstrates exhibit very wideband directivity enhancement. In this paper, we study the transformation of transverse electric field that is achieved by the TPG superstrate. This provides physical insight into the operating principle of such RCAs. Two fictitious apertures are used to record and compare the phase of the field within the cavity of the RCA as well as above its TPG superstrate. It is found that the TPG superstrate significantly reduces the phase variation of the aperture field over most of the operating bandwidth, thus resulting in wideband directive characteristics. Numerical results as well as measurements are presented showing wideband antenna performance with a peak directivity exceeding 16 dBi.
He, T, Zhu, J, Dah-Chuan Lu, D, Zheng, L, Aghdam, MM & Zhang, J 1970, 'Comparison study of electric vehicles charging stations with AC and DC buses for bidirectional power flow in smart car parks', IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, IEEE, Beijing, China, pp. 4609-4614.
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© 2017 IEEE. This paper presents a comparison study of AC bus and DC bus topologies for electric vehicle (EV) battery chargers in smart car parks. The two charger systems are compared from two aspects: the features from the user side and the power quality on the grid side. Considering the system reliability, cost, size and conversion stage, the pros and cons of AC and DC buses systems are introduced and summarized. To compare the electric parameters of the power quality, model predictive control (MPC) algorithm is proposed and applied to operate in grid-to-vehicle (G2V), vehicle-to-grid (V2G), vehicle-for-grid (V4G) modes. An cost function is designed in MPC to track the active and reactive powers references provided by the main grid. The controllers for AC and DC buses to determine the the active and reactive powers relationships among the grid, charging stations and the storage system are designed, respectively. In terms of power ripple, total harmonic distortion (THD) and execute time, comparative simulations of the two topologies are performed under the proposed operations in Matlab/Simulink. The obtained results show that both the two system structures can operate effectively and the commands from the grid and EVs customers can be satisfied. Fast dynamic performance and good steady-state response are achieved in two systems. However, the power ripple, THD, and the execute time obtained from DC bus topology are much lower compared with the AC bus system.
He, X, Mohapatra, P, Sandhu, R, Guo, S, Di, MB, Lu, J, Mosse, D & Pasricha, S 1970, 'Message from the IEEE TrustCom / BigDataSE / ICESS 2017 General Chairs', 2017 IEEE Trustcom/BigDataSE/ICESS, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, p. xvi.
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Hoang, D & Dang, TD 1970, 'FBRC: Optimization of task Scheduling in Fog-Based Region and Cloud', 2017 IEEE Trustcom/BigDataSE/ICESS, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, Sydney, NSW, Australia, pp. 1109-1114.
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© 2017 IEEE. Fog computing preserves benefits of cloud computing and is strategically positioned to address effectively many local and performance issues because its resources and specific services are virtualized and located at the edge of the customer premises. Resource management is a critical issue affecting system performance significantly. Due to the complex distribution and high mobility of fog devices, computation resources still experience high latencies in fog's large coverage area. This paper considers a Fog-based Region and Cloud (FBRC) in which requests are locally handled not just by a region but multiple regions when additional resources are needed. An efficient task scheduling mechanism is thus essential to minimize the completion time of tasks and improve user experiences. To this end, two issues are investigated in the paper: 1) designing a fog-based region architecture to provide nearby computing resources; 2) investigating efficient scheduling algorithms to distribute tasks among regions and remote clouds. To deal with the complexity of scheduling tasks, a heuristic-based algorithm is proposed based on our formulation and validated by extensive simulations.
Hoang, DT, Niyato, D & Wang, P 1970, 'Optimal Cost-Based Cyber Insurance Policy Management for Mobile Services', 2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), IEEE, Toronto, ON, Canada, pp. 1-5.
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© 2017 IEEE. This paper introduces a cyber insurance policy management for the mobile networks in which if a mobile user agrees to purchase an insurance policy from an insurer, the loss of the mobile user, i.e., the insured, will be covered by the insurance policy when the risks happen. To protect mobile users from cyber attacks, the insurer can deploy security protection solutions, e.g., anti-virus software or personal firewall, to the insureds, thereby reducing the risks for mobile users. However, when the solutions are deployed, they will incur a certain cost to the insurer. Therefore, we propose a stochastic optimization based on the reserve state of the insurer and the number of active mobile users to determine whether the protection solutions should be deployed or not to maximize the revenue for the insurer. The performance evaluation reveals that the optimal policy can achieve significantly higher revenue than those of baseline schemes for the insurer. Alternatively, the coalitional game is studied to share the reward among the insurers, and we show that the insurers can gain higher individual rewards through the cooperation.
Hoang, DT, Niyato, D, Wang, P & Kim, DI 1970, 'Optimal time sharing in RF-powered backscatter cognitive radio networks', 2017 IEEE International Conference on Communications (ICC), ICC 2017 - 2017 IEEE International Conference on Communications, IEEE, Paris, France.
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© 2017 IEEE. In this paper, we propose a novel network model for RF-powered cognitive radio networks and ambient backscatter communications. In the network under consideration, each secondary transmitter is able to backscatter primary signals to the gateway for data transfer or to harvest energy from the primary signals and then use that energy to transmit data to the gateway. To maximize overall network throughput of the network, we formulate an optimization problem with the aim of finding not only an optimal tradeoff between data backscattering time and energy harvesting time, but also time sharing among multiple secondary transmitters. Through the numerical results, we demonstrate that the solution of the optimization problem always achieves the best performance compared with two other baseline schemes.
Hoang, DT, Niyato, D, Wang, P, Domenico, AD & Strinati, EC 1970, 'Optimal Cross Slice Orchestration for 5G Mobile Services', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Chicago, IL, USA, USA.
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5G mobile networks encompass the capabilities of hosting a variety ofservices such as mobile social networks, multimedia delivery, healthcare,transportation, and public safety. Therefore, the major challenge in designingthe 5G networks is how to support different types of users and applicationswith different quality-of-service requirements under a single physical networkinfrastructure. Recently, network slicing has been introduced as a promisingsolution to address this challenge. Network slicing allows programmable networkinstances which match the service requirements by using network virtualizationtechnologies. However, how to efficiently allocate resources across networkslices has not been well studied in the literature. Therefore, in this paper,we first introduce a model for orchestrating network slices based on theservice requirements and available resources. Then, we propose a Markovdecision process framework to formulate and determine the optimal policy thatmanages cross-slice admission control and resource allocation for the 5Gnetworks. Through simulation results, we show that the proposed framework andsolution are efficient not only in providing slice-as-a-service based on theservice requirements, but also in maximizing the provider's revenue.
Hoang, DT, Niyato, D, Wang, P, Kim, DI & Le, LB 1970, 'Overlay RF-powered backscatter cognitive radio networks: A game theoretic approach', 2017 IEEE International Conference on Communications (ICC), ICC 2017 - 2017 IEEE International Conference on Communications, IEEE, Paris, France.
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© 2017 IEEE. In this paper, we study an overlay RF-powered cognitive radio network with ambient backscatter communications. In the network, when the channel is occupied, the secondary transmitter (ST) can perform either energy harvesting or data transmission using ambient backscattering technique to a gateway. We consider the case that the gateway charges the ST a certain price if the ST transmits information. This leads to questions of how to determine the best price for the gateway and how to find the optimal backscatter time. To address this problem, we propose a Stackelberg game in which the gateway is the leader adapting the price to maximize its profit in the first stage. Meanwhile, the ST chooses its backscatter time to maximize its utility in the second stage. To analyze the game, we apply the backward induction technique. We show that the game always has a unique subgame perfect Nash equilibrium. Additionally, our results provide insights on the impact of the competition on the players' profit and utility.
Hoang, DT, Niyato, D, Wang, P, Wang, SS, Nguyen, D & Dutkiewicz, E 1970, 'A Stochastic Programming Approach for Risk Management in Mobile Cloud Computing', IEEE Wireless Communications and Networking Conference, WCNC, IEEE Wireless Communications and Networking Conference, IEEE, Barcelona, Spain, pp. 1-6.
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The development of mobile cloud computing has brought many benefits to mobileusers as well as cloud service providers. However, mobile cloud computing isfacing some challenges, especially security-related problems due to the growingnumber of cyberattacks which can cause serious losses. In this paper, wepropose a dynamic framework together with advanced risk management strategiesto minimize losses caused by cyberattacks to a cloud service provider. Inparticular, this framework allows the cloud service provider to selectappropriate security solutions, e.g., security software/hardware implementationand insurance policies, to deal with different types of attacks. Furthermore,the stochastic programming approach is adopted to minimize the expected totalloss for the cloud service provider under its financial capability anduncertainty of attacks and their potential losses. Through numericalevaluation, we show that our approach is an effective tool in not only dealingwith cyberattacks under uncertainty, but also minimizing the total loss for thecloud service provider given its available budget.
Hoang, TM, Tuan, HD & Duong, TQ 1970, 'Secure Massive MIMO Amplify-and-Forward Relaying Networks in Poisson Field', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, NSW, Australia, pp. 1-5.
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© 2017 IEEE. We consider a cooperative relay network in the presence of many eavesdroppers whose locations are distributed according to a homogeneous Poisson point process. The relay, which operates in amplify-and-forward protocol, has very large transmit and receive antenna arrays, while other nodes are equipped with a single antenna. We assume that the relay exploits maximum ratio combing (MRC) in the uplink and maximum ration transmission in the downlink, while all eavesdroppers are able to exploit MRC to maximize the received signals. In addition, there is no perfect channel state information of any eavesdroppers since all eavesdroppers in practice tend to hide from the legitimate users. Furthermore, we suppose that there are direct links between source and eavesdroppers, while a direct link between source and destination does not exist. Under such assumptions, which are totally biased towards eavesdroppers, we examine the security performance of the proposed system throughout secrecy outage probability and connection outage probability.
Hou, ZJ, Xue, Q, Yang, Y, Zhu, X & Dutkiewicz, E 1970, 'Miniaturized millimeter-wave on-chip bandpass filter design in 0.13-μm SiGe BiCMOS technology', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, QLD, Australia, pp. 1-5.
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© 2017 IEEE. The full potential of active device in current Si-based technology has almost reached its limit. However, the passive devices that are integrated with transistors in the same technology have yet been fully explored. Improving the quality of on-chip passive devices is not only beneficial for energy efficiency, but also has significant meaning in cost reduction for a system-on-chip (SoC) solution while the passive circuits are miniaturized. A review of on-chip circuit miniaturization techniques for bandpass filter (BPF) design is demonstrated in this paper. Although the recently presented broadside-coupled meander line resonator (BCMLR) is very compact, the stopband attenuation is quite limited. To solve this issue, a ring-based structure is studied in this work. Using this approach, the size of the proposed millimeter-wave on-chip BPF can be significantly reduced due to the multi-mode characteristics of the proposed resonators, of which the equivalent circuits can be effectively modeled through the accurately extracted lumped components values. Our works exhibit excellent performance comparing with the state-of-the-art designs.
Hou, ZJ, Yang, Y, Zhu, X, Liao, S, Man, SK & Xue, Q 1970, 'A 320 GHz on-chip slot antenna array using CBCPW feeding network in 0.13-μm SiGe technology', 2017 IEEE MTT-S International Microwave Symposium (IMS), 2017 IEEE/MTT-S International Microwave Symposium - IMS 2017, IEEE, Honolulu, Hawaii, pp. 843-846.
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© 2017 IEEE. A 320 GHz on-chip 2 × 2 antenna array employing a compact feeding network is presented in this paper. The feeding network is designed based on the conducted-back coplanar waveguide (CBCPW) transmission line with a compact size, which has the full shielding performance providing good isolation from circuits around or below the CBCPW transmission lines. The proposed on-chip feeding network and antenna array are fabricated using standard 0.13-μm SiGe process. The antenna array is measured using a specially designed backside radiation measurement system. The simulated and measured results show that the backside radiation on-chip antenna array has a measured peak gain of 7.9 dBi at 320 GHz.
Hu, D, Xu, W, Dian, R, Liu, Y & Zhu, J 1970, 'Dynamic loss minimization control of linear induction machine', 2017 IEEE Energy Conversion Congress and Exposition (ECCE), 2017 IEEE Energy Conversion Congress and Exposition (ECCE), IEEE, Cincinnati, OH, USA, pp. 3598-3603.
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© 2017 IEEE. The linear induction machine (LIM) suffers heavily from low efficiency due to its large air-gap length, the influence of end-effects, and the partial load conditions. Several loss minimization control (LMC) techniques have been developed for LIM to adjust the flux to an optimal level to reduce the losses in the steady state. However, these methods are not applicable during dynamic process, since it requires much more complex modeling that leads to heavy computational burden due to the change of thrust in dynamic operation. In this paper, to solve the aforementioned problem, a novel LIM dynamic loss model is derived based on the full analysis of copper and core losses. A simple solution for online estimation of the optimal flux in dynamic operation and a practical dynamic LMC scheme are proposed to minimize the losses. Simulations and experiments are fully performed on a 3 kW LIM prototype, and demonstrate the effectiveness of the proposed method in loss minimization and energy saving during the dynamic process.
Hu, D, Xu, W, Lei, G & Zhu, J 1970, 'Design and control optimization of linear induction motor drive for efficiency improvement', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. Linear induction motor (LIM) drive suffers heavily from low efficiency due to its large air-gap length, the end-effects, and the partial load working conditions. Therefore, an optimization method is proposed in this paper to improve the LIM drive operating efficiency from both design and control levels. First, the genetic algorithm (GA) is applied to design optimization of LIM to attain higher efficiency and power factor. Second, a novel loss model for LIM drive is proposed to analyze both LIM loss and inverter loss. Third, efficiency optimization control (EOC) scheme based on the loss model is put forward to improve the LIM drive working efficiency. Simulations and experimental results validate the effectiveness of the proposed method in efficiency improvement of LIM drive under various operation conditions.
Hussein, F & Piccardi, M 1970, 'Minimum-Risk Structured Learning of Video Summarization', 2017 IEEE International Symposium on Multimedia (ISM), 2017 IEEE International Symposium on Multimedia (ISM), IEEE, Taichung, Taiwan.
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Video summarization is an important multimedia task for applications such as video indexing and retrieval, video surveillance, human-computer interaction and video "storyboarding". In this paper, we present a new approach for automatic summarization of video collections that leverages a structured minimum-risk classifier and efficient submodular inference. To test the accuracy of the predicted summaries we utilize a recently-proposed measure (V-JAUNE) that considers both the content and frame order of the original video. Qualitative and quantitative tests over two action video datasets - the ACE and the MSR DailyActivity3D datasets - show that the proposed approach delivers more accurate summaries than the compared minimum-risk and syntactic approaches.
Islam, M, Nadarajah, M & Hossain, J 1970, 'Dynamic behavior of transformerless PV system on the short-term voltage stability of distribution network', 2017 IEEE Power & Energy Society General Meeting, 2017 IEEE Power & Energy Society General Meeting (PESGM), IEEE, Chicago, IL.
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Islam, MZ, Yasmin Koli, MN & Esselle, KP 1970, 'Design and Improvement of Pattern Quality in Circularly Polarised Slot Array Antenna for Direct Broadcast Satellite Applications', 2017 2nd International Conference on Electrical & Electronic Engineering (ICEEE), 2017 2nd International Conference on Electrical & Electronic Engineering (ICEEE), IEEE, pp. 1-4.
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© 2017 IEEE. A circularly polarised radial line slot array antenna (CP-RLSA) is proposed in this paper for direct broadcast satellite applications. A new design suggestion has been introduced and investigated in this study to improve the performance and pattern quality of the antenna. The antenna is composed of spiral rings on the top plate and made with several thousand of slot pairs. The antenna supports waveguide like structure which is composed of air cavity and dielectric materials. An antenna prototype operating at 20 GHz was designed and simulated. The experimental measurements and simulation results show that the antenna has successfully satisfied the required technical specification. The antenna has achieved a maximum gain of 32.2 dBic at 19.4 GHz. The CP-RLSA antenna has demonstrated an radiation efficiency of 95.3% and a total efficiency of 90.3% at 20 GHz. The antenna has also fulfilled the condition of circular polarisation, i.e. axial ratio is below 3-dB level with appropriate radiation patterns. At the operating frequency 20 GHz, the antenna has achieved a gain of 28.1 dBic with side lobe level as low as-14.4 dB.
Ismaiel, B, Abolhasan, M, Smith, DB, Ni, W & Franklin, DR 1970, 'A Survey and Comparison of Device-to-Device Architecture Using LTE Unlicensed Band.', VTC Spring, IEEE Vehicular Technology Conference, IEEE, Sydney, NSW, Australia, pp. 1-5.
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© 2017 IEEE. Due to the rapid increase in data traffic, one of the solutions provided by mobile operators is to operate Long Term Evolution (LTE) in the unlicensed 5GHz band, as the licensed spectrum is becoming scarce. Mobile operators can expand their network capacity by operating LTE in the unlicensed band at lower cost when compared with using other licensed bands. Device to Device (D2D) communication, proven to be another effective way to enhance the capacity of a network, enables direct data exchange of localized traffic of users in proximity. Applying D2D communication to LTE unlicensed 5GHz band will further improve the network performance and user experience. In this article, we will discuss the new type of solutions that have been proposed for LTE operating in an unlicensed 5GHz band that includes; LTE-Unlicensed (LTE-U), LTE-License Assisted Access (LTE-LAA), LTE WiFi Link Aggregation (LWA), and MuLTEfire. We will discuss the important features along with their advantages and disadvantages and compare these technologies as well. We simulate LTE-LAA, LWA and MuLTEfire technologies in the presence of Wi-Fi hotspot and compare their results. Furthermore, we apply D2D communication to these technologies and from the results we conclude that MuLTEfire can increase the throughput drastically but network saturates quickly. Whereas, applying D2D communication with LWA is beneficial for a scalable network as it will not only increase the network throughput but will increase the network capacity as well.
Ismaiel, B, Abolhasan, M, Smith, DB, Ni, W & Franklin, DR 1970, 'Scalable MAC protocol for D2D communication for future 5G networks.', CCNC, 2017 14th IEEE Annual Consumer Communications & Networking Conference, IEEE, Las Vegas, NV, USA, pp. 542-547.
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© 2017 IEEE. Device-to-device communication (D2D) will be an integral part of 5G wireless networks. Device-to-Device (D2D) communication provide the additional resources to the cellular users for spatially reusing licensed/unlicensed spectrum by establishing direct communication. Although, D2D communication is gaining significant attention towards offloading traffic in heterogeneous networks in licensed band, no attention has been given to offload traffic in an unlicensed band in a centralized manner. However, a major challenge of D2D communication is managing resources in an efficient manner in a heterogeneous network. This paper will direct a new approach to D2D Communication and will present a scalable MAC protocol for D2D communications based on Point Coordination Function (PCF) access mechanism. The importance of PCF access mechanism is that it operates in a centralized manner and highly suitable for the dense environment, hence, can create a centralized control in a distributive manner. In this article, we propose an innovative three tier 5G architecture for D2D communication, which will offload cellular traffic from the cellular network to the WLAN in a dense environment. Moreover, we will present a new centralized scalable MAC protocol for D2D communication between WLAN users, based on the IEEE 802.11 Point Coordination Function (PCF) access mechanism. Our simulation results show that the proposed MAC scheme can increase the capacity of the network and perform better relative to the legacy Distributed coordination Function (DCF) defined in IEEE 802.11.
Jamborsalamati, P, Fernandez, E, Hossain, MJ & Rafi, FHM 1970, 'Design and implementation of a cloud-based IoT platform for data acquisition and device supply management in smart buildings', 2017 Australasian Universities Power Engineering Conference (AUPEC), 2017 Australasian Universities Power Engineering Conference (AUPEC), IEEE.
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© 2017 IEEE. Increased numbers of installed IoT devices and more complex building management algorithms make vital a secure, reliable, and cloud-based IoT platform, offering provisions for devices to communicate and react to predefined situations. This platform facilitates data acquisition, management, and interactions among IoT devices in order to exchange information including measurement data and control signals with controllers via a two-way communication mechanism. In this paper, an IoT platform to implement a device-supply management algorithm in a smart building, aiming to supply higher-priority devices from solar power and to maximize solar-power utilization, has been designed and implemented. Message Queue Telemetry Transport (MQTT), which is the state-of-the-art Internet of Things (IoT) protocol, has been adopted in this work to incorporate communications between the devices and the controller. MQTT publisher and subscriber are deployed in the Python programming language. A cloud-based data aggregation platform has been used with an interface to MATLAB, in which the device management algorithm runs. From the results, it could be observed that the IoT platform successfully achieves the goals of the designed device-supply management algorithm.
Jamborsalamati, P, Sadu, A, Ponci, F, Monti, A & Hossain, MJ 1970, 'Improvement of supply restoration in multi-spare-feeder active distribution grids using IEC 61850', 2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), 2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), IEEE, pp. 1-5.
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© 2017 IEEE. Automating the entire process of Fault Location, Isolation, and Service Restoration (FLISR) can significantly reduce the minutes of interruption (caused by a fault) in distribution grids. Consequently, it can reduce the penalties paid by utilities for the outage of the end customers. This could be achieved through implementation of cyber-physical systems (CPS) which are made of Intelligent Electronic Devices (IEDs) capable of reliable and fast communications. This paper proposes a novel distributed FLISR algorithm which optimizes previously developed supply restoration strategies in terms of minimizing the losses in the grid. Furthermore, the test-case scenario considered in this paper is closer to real-world scenarios wherein there are multiple spare feeders which could be utilized in supply restoration strategies after fault occurrence. The proposed algorithm is paired with the GOOSE communication protocol presented in IEC61850 and is implemented in a real-time Hardware-in-the-Loop (HIL) platform using the Real Time Digital Simulator (RTDS). From results it can be concluded that the improved service restoration algorithm in this paper successfully selects the spare feeder with less losses and connects that to the non-faulty loads properly.
Jamborsalamati, P, Sadu, A, Ponci, F, Monti, A & Hossain, MJ 1970, 'Improvement of Supply Restoration in Multi-Spare-Feeder Active Distribution Grids using IEC 61850', 2017 IEEE INNOVATIVE SMART GRID TECHNOLOGIES - ASIA (ISGT-ASIA), 7th IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), IEEE, Univ Auckland, Auckland, NEW ZEALAND, pp. 67-71.
Ji, L-Y, Zhu, H-L, Qin, P-Y & Guo, YJ 1970, 'Broadband partially reflective surface antenna with tapered corrugated ground', 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, IEEE, San Diego, CA, USA, pp. 509-510.
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© 2017 IEEE. This paper proposes a broadband Partially Reflective Surface antenna. It consists of a U-slot microstrip antenna as the source, an FR4 superstrate as the partially reflective surface, and a tapered corrugated ground structure. By employing the corrugated ground, the 3dB gain bandwidth is improved from 17% to 24% with the maximum realized gain and the 10dB impedance bandwidth unchanged. Therefore, the corrugated ground structure can be a good candidate to enhance the gain bandwidth of PRS antennas.
Jia, H, Cheng, M, Zhu, J, Cai, J, Cao, Y & Jia, Z 1970, 'Design and analysis of a bearingless doubly salient permanent magnet machine', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. This paper investigates a three-phase 12/8 poles bearingless doubly salient permanent magnet machine (BDSPMM) with suspending windings, armature windings and PMs on the stator. Based on the topology and operating principle, the influence of PM magnetization length on the performance of the BDSPMM is analyzed and a mathematical model of radial suspending force is deduced from the magnetic circuit. The 2D finite element analysis (FEA) is carried out to verify the mathematical model. A prototype BDSPMM has been built. The simulation and experiment results show that the correctness of the motor design method and mathematical model, which laid a theoretical foundation for the high performance control strategy of BDSPMM.
Jiang, J, Chaczko, Z, Al-Doghman, F & Narantaka, W 1970, 'New LQR Protocols with Intrusion Detection Schemes for IOT Security', 2017 25th International Conference on Systems Engineering (ICSEng), 2017 25th International Conference on Systems Engineering (ICSEng), IEEE, Las Vegas, NV, USA, pp. 466-474.
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© 2017 IEEE. Link quality protocols employ link quality estimators to collect statistics on the wireless link either independently or cooperatively among the sensor nodes. Furthermore, link quality routing protocols for wireless sensor networks may modify an estimator to meet their needs. Link quality estimators are vulnerable against malicious attacks that can exploit them. A malicious node may share false information with its neighboring sensor nodes to affect the computations of their estimation. Consequently, malicious node may behave maliciously such that its neighbors gather incorrect statistics about their wireless links. This paper aims to detect malicious nodes that manipulate the link quality estimator of the routing protocol. In order to accomplish this task, MINTROUTE and CTP routing protocols are selected and updated with intrusion detection schemes (IDSs) for further investigations with other factors. It is proved that these two routing protocols under scrutiny possess inherent susceptibilities, that are capable of interrupting the link quality calculations. Malicious nodes that abuse such vulnerabilities can be registered through operational detection mechanisms. The overall performance of the new LQR protocol with IDSs features is experimented, validated and represented via the detection rates and false alarm rates.
Jiang, Z, Huynh, DQ, Zhang, J & Wu, Q 1970, 'Part-Based Data Association for Visual Tracking', 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), IEEE, Sydney, NSW, Australia, pp. 1-8.
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© 2017 IEEE. We present a method that integrates a part-based sparse appearance model in a Bayesian inference framework for tracking targets in video sequences. We formulate the sparse appearance model as a set of smoothed colour histograms corresponding to the object windows detected by the Deformable Part Model (DPM) detector. The data association of each body part between frames is solved based on the position constraint, appearance coherence, and motion consistency. To deal with missing and noisy observations, the part detection window in the following frame is also predicted using an interacting multiple model (IMM) tracker. We have tested our tracking method on all the video sequences that involve people in upright poses from the TB-50 and TB-100 benchmark videos datasets. Our experimental results show that our tracking method outperforms six state-of-the-art tracking techniques.
Kafle, YR, Hasan, SU, Kashif, M, Hossain, J & Town, GE 1970, 'A new PWM Shoot-through control for voltage-fed quasi-z-source DC/DC converters', 2017 IEEE International Telecommunications Energy Conference (INTELEC), 2017 IEEE International Telecommunications Energy Conference (INTELEC), IEEE, Gold Coast, AUSTRALIA, pp. 494-497.
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Kale, A & Chaczko, Z 1970, 'iMuDS: An Internet of Multimodal Data Acquisition and Analysis Systems for Monitoring Urban Waterways', 2017 25th International Conference on Systems Engineering (ICSEng), 2017 25th International Conference on Systems Engineering (ICSEng), IEEE, Las Vegas, NV, USA, pp. 431-437.
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© 2017 IEEE. Freshwater monitoring is becoming an essential activity due to limited availability of drinking water and an increasing presence of various pollutants. Tons of toxic waste added to water sources everyday contributes to the decrease in the planet's biodiversity and even an extinction of many species of animals and marine life. Many millions of birds perish each year due to waterway pollution. New technologies such as the Internet of Things (IoT), Wireless Sensor Networks and computer vision allow us to monitor fresh water sources in a continuous mode. To minimize the effects of pollution, various monitoring activities can be planned and executed for very large areas and geographical regions. This work presents a system architecture for the IoT-based multimodal data acquisition and analysis system. The idea is to deploy sensor clusters in various locations of a waterway to create a network of sensing and measuring smart devices. Every cluster of such devices can be perceived as a 'thing'. Such a 'thing' or a node has camera sensing modalities for a macro level pollution detection with analog sensors to measure microlevel water parameters. Our solution involves a low power microprocessor devices provisioned to capture raw data, extract features from the raw data and then transmit these data to the Cloud for further analysis and reporting. A 5G mobile network communication is used for data transmission. The Cloud server runs a software framework that supports a sophisticated analysis and trending of various environmental parameters such as surface density of water, salinity, temperature, etc. The proposed software framework has a set of computational algorithms to process features supplied by each node. These algorithms can classify features into various classes like floating objects, water salinity level, etc. An experiment to simulate the 'IoT' data acquisition is conducted to validate the proposed solution. Based on a case study, this soluti...
Kamal, MS, Parvin, S, Saleem, K, Al-Hamadi, H & Gawanmeh, A 1970, 'Efficient low cost supervisory system for Internet of Things enabled smart home', 2017 IEEE International Conference on Communications Workshops (ICC Workshops), 2017 IEEE International Conference on Communications Workshops (ICC Workshops), IEEE.
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Karamanakos, P, Geyer, T & Aguilera, RP 1970, 'Computationally efficient long-horizon direct model predictive control for transient operation', 2017 IEEE Energy Conversion Congress and Exposition (ECCE), 2017 IEEE Energy Conversion Congress and Exposition (ECCE), IEEE, Cincinnati, OH, USA, pp. 4642-4649.
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© 2017 IEEE. In this paper we present modifications in the sphere decoder initially introduced in [1] and modified in [2] that allow for its implementation in transient operation. By investigating the geometry of the integer problem underlying direct model predictive control (MPC), a new sphere that guarantees feasibility and includes a significant smaller number of candidate solutions is computed. In a first analysis, the computational complexity can be reduced by up to 99.7% when a variable speed drive system consisting of a three-level neutral point clamped (NPC) voltage source inverter and a medium-voltage induction machine is examined. As also shown, optimality is sacrificed only to a limited extent, thus maintaining the very fast transient response inherent to direct MPC.
Karmokar, DK & Guo, YJ 1970, 'Planar leaky-wave antennas for low-cost radar', 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Verona, ITALY, pp. 112-115.
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Kashif, M, Hossain, MJ, Kafle, YR & Rahman, MS 1970, 'A comparative study of two current-control techniques applied to a three-phase three-level active power filter', 2017 IEEE International Telecommunications Energy Conference (INTELEC), 2017 IEEE International Telecommunications Energy Conference (INTELEC), IEEE, Gold Coast, AUSTRALIA, pp. 357-362.
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Kashif, M, Hossain, MJ, Zhuo, F, Shuhuai Shi & Soon, JL 1970, 'An advanced harmonic extraction technique applied to a three-phase three-level active power filter', 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia (IFEEC 2017 - ECCE Asia), 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia (IFEEC 2017 - ECCE Asia), IEEE, Kaohsiung, TAIWAN, pp. 364-369.
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Katare, KK, Biswas, A & Esselle, KP 1970, 'Directive array based pattern reconfigurable antenna', 2017 11th European Conference on Antennas and Propagation (EUCAP), 2017 11th European Conference on Antennas and Propagation (EUCAP), IEEE, Paris, FRANCE, pp. 2029-2032.
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Katare, KK, Biswas, A & Esselle, KP 1970, 'Gain enhancement of pattern diversity antenna by improving phase uniformity', 2017 11th European Conference on Antennas and Propagation (EUCAP), 2017 11th European Conference on Antennas and Propagation (EUCAP), IEEE, Paris, FRANCE, pp. 2033-2036.
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Khademlahashy, A, Li, L, Every, J & Zhu, J 1970, 'A review on protection issues in micro-grids embedded with distribution generations', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 913-918.
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© 2017 IEEE. According to recent developments, the application of distributed generations (DGs) has become popular especially in distribution systems. The high utilization of distributed generating resources in modern power systems can cause new challenges from protection coordination perspectives. Changing the distribution system structure from single-supply radial system to multi-source ring network, leads to the bidirectional power flow and also has a vital impact on protection coordination issues. In addition, micro-grids can be operated under grid-connected as well as islanded mode, and fault current is extensively different for these two operation modes. Therefore, traditional protection algorithms cannot be used in the advancement of power systems. In recent years, several research studies have been conducted to investigate the improvement of protection schemes in micro-grids. This paper presents a comprehensive review on protection problems resulting from micro-grids embedded with DGs, and discusses some alternate protection strategies.
Khademlahashy, A, Mehta, G, Li, L & Zhu, J 1970, 'Impact of using current limiting reactor on the existing circuit breakers in micro-grids', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. Recently, distributed generations (DGs) have been widely used in distribution networks. Using DGs in the grid-connected mode leads to increase of the fault current level. This increase can affect the existing equipment especially circuit breakers (CBs) and operation of overcurrent relays. Current limiting reactor (CLR) has been proposed to reduce the effect of micro-grids (MGs) on the existing protection scheme during fault conditions by many researchers. However, there are some factors for interrupting the current by CBs which do not only depend on the fault current magnitude. Transient recovery voltage (TRV) and rate of rise recovery voltage (RRRV) can also affect the operation of CBs. This paper presents the equivalent analysis of the TRV and RRRV across a CB connected with a CLR. The transient stability is studied through simulation of a practical network, which shows the impact of using CLRs on the burden of CBs. In addition, some possible solutions are studied in this paper.
Khademlahashy, A, Mehta, G, Li, L & Zhu, J 1970, 'Lifetime evaluation of HV transformers', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, pp. 1-5.
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© 2017 IEEE. Power transformers are one of the most important equipment in power substations and distribution systems. As its price is about 55% of the whole substation price, it can be called the valuable element in the power grid. Thus, the lifetime management based on economical and technical indexes is highly essential for facilitating asset management and achieving higher reliability in the power system. This study presents the factors that can affect ageing transformers and analyzes oil test parameters. Dissolved gas analysis (DGA) is performed and some existing methods for evaluating of transformer operation based on DGA are compared. The pros and cons of each method are shown and a simple method to assess transformer condition is found. Also, three power transformers with real values and oil samples are studied for lifetime evaluation, and some possible solutions are proposed for better operation and maintenance.
Khan, SA, Guo, Y & Zhu, J 1970, 'Model predictive control applied to a single phase seven-level active rectifier', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. This paper presents an improved single phase seven-level active rectifier architecture controlled by finite control set model predictive control (FCS-MPC). The FCS-MPC is designed to enable power conversion with a unity power factor and generate seven level voltage waveform at the input. The proposed active rectifier architecture reduces harmonic contents of the rectifier input current by producing different voltage levels at the rectifier input. Owing to the architecture and multilevel operation, it reduces the EMI filter size, input current harmonic, the voltage rating on devices and switching losses that are lower than those of conventional three-level rectifier topologies. The proposed converter can also be operated as a multilevel inverter. Extensive simulation results are presented to verify the proposed converter when the load changes, the reference active and reactive power changes.
Khokle, R, Esselle, K, Heimlich, M & Bokor, D 1970, 'Orthopaedic implant micromotion sensing using an eddy current sensor', 2017 IEEE Life Sciences Conference (LSC), 2017 IEEE Life Sciences Conference (LSC), IEEE, Sydney, AUSTRALIA, pp. 125-128.
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Khokle, RP, Esselle, KP, Heimlich, M & Bokor, D 1970, 'Design of a miniaturized bone implantable antenna for a wireless implant monitoring device', Loughborough Antennas & Propagation Conference (LAPC 2017), Loughborough Antennas & Propagation Conference (LAPC 2017), Institution of Engineering and Technology.
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© 2017 Institution of Engineering and Technology. All rights reserved. In this paper, we present a spiral loop type antenna, implanted in the tibial bone. The antenna has been designed for fabrication on commercially available RT Duroid 6010 (Hr =10.2) substrate and encapsulated in biologically compatible Polydimethylsiloxane (PDMS) material (Hr=2.6). The antenna has a footprint of 2.6mm x 2.6 mm and a height of 1.94 mm. The antenna operates at the 2.4 GHz ISM band with the peak gain of -36.2 dBi.
Khruahong, S, Kong, X, Sandrasegaran, K & Liu, L 1970, 'Multi-Level Indoor Navigation Ontology for High Assurance Location-Based Services', 2017 IEEE 18th International Symposium on High Assurance Systems Engineering (HASE), 2017 IEEE 18th International Symposium on High Assurance Systems Engineering (HASE), IEEE, Singapore, Singapore.
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Indoor navigation will become an important application on a smartphone for Location-Based Service (LBS). An indoor navigation system should work under normal circumstances and during emergencies, such as fires, during a building power shut down, alarm, etc. The LBS should be able tohelp users find the best exit route to the outside of the buildingunder all circumstances and with high reliability. In thisresearch, we develop an indoor ontology model for indoornavigation. This ontology model defines the indoor environmentattributes such as location nodes, and connection points. Thelocation nodes with the location information allow navigation in the indoor environment. Connection points are able to separate the map zones and the building floors into a "Map sheet." This ontology approach allows the LBS works in both normal circumstances and emergencies. This model provides a reliable indoor navigation system for LBS.
Kiyani, A, Hashmi, RM & Esselle, KP 1970, 'Dense, planar arrays of compact Resonant Cavity Antennas', 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, IEEE, San Diego, CA, pp. 1973-1974.
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Kong, F, Sun, X, Leung, VCM, Guo, YJ, Zhu, Q & Zhu, H 1970, 'Queue-Aware Small Cell Activation for Energy Efficiency in Two-Tier Heterogeneous Networks', 2017 IEEE Wireless Communications and Networking Conference (WCNC), 2017 IEEE Wireless Communications and Networking Conference (WCNC), IEEE, San Francisco, CA, USA.
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© 2017 IEEE. In heterogeneous networks (HetNets), the network energy efficiency is critically determined by the base station (BS) deployment density. In this paper, we consider a BS density optimization problem by turning on only a fraction of micro BSs according to an activation ratio to minimize the network average power consumption per area in a 2- tier HetNet. In contrast to previous studies where a BS is assumed to be transmitting packets all the time, such that the network power consumption monotonically increases as the BS density increases, we assume that each BS can be busy or idle depending on the dynamic packet arrivals. The network power consumption is thus closely related to the average traffic intensity of each tier. With the assumption of universal spectrum reuse, the average traffic intensity of each tier is found to be uniquely determined by a set of fixed-point equations, based on which the network average power consumption per area is characterized. Simulation results demonstrate that the network average power consumption per area can be minimized by properly tuning the activation ratio. It is further revealed that the optimal activation ratio increases as the mean packet arrival rate of each user increases.
Kovaleva, M, Bulger, D & Esselle, KP 1970, 'Efficient optimization of a simple compact resonant cavity antenna', 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, IEEE, San Diego, CA, pp. 345-346.
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Kusakunniran, W, Qiang Wu, Ritthipravad, P & Zhang, J 1970, 'Three-stages hard exudates segmentation in retinal images', 2017 9th International Conference on Information Technology and Electrical Engineering (ICITEE), 2017 9th International Conference on Information Technology and Electrical Engineering (ICITEE), IEEE, Phuket, Thailand, pp. 1-6.
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© 2017 IEEE. This paper proposes a three-stages method of hard exudate segmentation in retinal images. The first stage is the pre-processing. The color transfer is applied to make all retinal images to have the same color characteristics, based on statistical analysis. Then, only a yellow channel of each image is used in the further analysis. The second stage is the blob initialization. The blob detection based on color, size, and shape including circularity and convexity is used to identify initial pixels of hard exudates. The detected blobs must not be inside the optic disk. The third stage is the segmentation. The graph cut is iteratively applied on partitions of the image. The fine-tune segmentation in sub-images is necessary because the portion of hard exudates is significantly less than the portion of non-hard exudates. The proposed method is evaluated using the two well-known datasets, namely e-ophtha and DIARETDB1, in both aspects of pixel-level and image-level. Based on the comprehensive comparisons with the existing works, the proposed method is shown to be very promising. In the image-level, it achieves 96% sensitivity and 94% specificity for the e-ophtha dataset, and 96% sensitivity and 98% specificity for the DIARETDB1 dataset.
Kusakunniran, W, Wu, Q & Zhang, J 1970, 'Action Recognition Based on Correlated Codewords of Body Movements', 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), IEEE, Sydney, Australia, pp. 1-8.
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© 2017 IEEE. Using spatio-temporal features is popular for action recognition. However, existing methods embed these local features into a global representation. Orders and correlations among local motions of each action are missing. This can make it difficult to distinguish closely related actions. This paper proposes a solution to address this challenge by encoding correlations of movements. Space-time interest points are detected in each action video. Then, feature descriptors are extracted from these key points and clustered into different codewords implicitly representing different characteristics of motions. The final representation of each action video is a combination of a bag of words and correlations between codewords. Then, the support vector machine is used as a classification tool. Based on the experimental results, the proposed method achieves a very promising performance and particularly outperforms the other existing methods that rely on spatio-temporal features.
Lai, W, Ni, W, Wang, H & Liu, RP 1970, 'Decentralized Relaying and Performance Analysis in Vehicular Ad Hoc Networks', 2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), IEEE, Toronto, ON, Canada, pp. 1-5.
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© 2017 IEEE. Vehicular Ad Hoc Networks (VANET) is an important network technology. Relay communication can effectively improve the connectivity and coverage of VANET, especially in distributed environments. Challenges arise from intense collision resulting from inherently synchronized relays. In this paper, we propose a decentralized relay scheme without collecting neighbor nodes' information. Particularly, we design a new score function to prioritize the relays based on their reception quality from source and channel conditions towards intended destination. A closed-form expression for packet delivery ratio (PDR) is derived based on time-out probabilities. Our analyses, validated by simulations, show that the proposed scheme, in terms of PDR, is much better than DAFMAC protocol.
Lalbakhsh, A & Esselle, KP 1970, 'Design of an improved resonant cavity antenna', 2017 International Conference on Electromagnetics in Advanced Applications (ICEAA), 2017 International Conference on Electromagnetics in Advanced Applications (ICEAA), IEEE, Verona, ITALY, pp. 1658-1660.
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Lalbakhsh, A, Afzal, MU, Esselle, KP & Smith, S 1970, 'Design of an artificial magnetic conductor surface using an evolutionary algorithm', 2017 International Conference on Electromagnetics in Advanced Applications (ICEAA), 2017 International Conference on Electromagnetics in Advanced Applications (ICEAA), IEEE, Verona, ITALY, pp. 885-887.
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Lalbakhsh, A, Afzal, MU, Esselle, KP & Smith, SL 1970, 'A fast design procedure for quadrature reflection phase', 2017 Progress in Electromagnetics Research Symposium - Fall (PIERS - FALL), 2017 Progress in Electromagnetics Research Symposium - Fall (PIERS - FALL), IEEE, Singapore, SINGAPORE, pp. 2364-2366.
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Lalbakhsh, A, Esselle, KP & Smith, SL 1970, 'Design of a single-slab low-profile frequency selective surface', 2017 Progress in Electromagnetics Research Symposium - Fall (PIERS - FALL), 2017 Progress in Electromagnetics Research Symposium - Fall (PIERS - FALL), IEEE, Singapore, SINGAPORE, pp. 2360-2363.
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Lawrence, C, Leong, TW, Gay, V, Woods, A & Wadley, G 1970, '#thismymob', Proceedings of the 29th Australian Conference on Computer-Human Interaction, OzCHI '17: 29th Australian Conference on Human-Computer Interaction, ACM, Brisbane, pp. 646-647.
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© 2017 Association for Computing Machinery. All rights reserved. We propose to hold a one-day workshop on developing projects relating to #thismymob: Digital Land Rights and Reconnecting Indigenous Communities at OzCHI 2017 Brisbane. See http://www.arc.gov.au/newsmedia/ news/thismymob-digital-land-rights-andreconnecting-indigenous-communities.
Le, AT, Tran, LC & Huang, X 1970, 'On Performance of Analog Least Mean Square Loop for Self-Interference Cancellation in In-Band Full-Duplex OFDM Systems', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. This paper evaluates the performance of an analog least mean square (ALMS) loop employed to cancel self-interference in in-band full-duplex (IBFD) orthogonal frequency division multiplexing (OFDM) systems. Cyclostationary analysis is applied to investigate the behavior of the ALMS filter. It is revealed that the performance of the ALMS filter for OFDM systems primarily depends on windowing function rather than pulse shaping as in single carrier systems. It is also noticed that the ALMS loop in OFDM systems provides a much higher level of sel-interference (SI) suppression because OFDM signals lead to reduced the error of the interference channel modelling with the adaptive filter. Simulations are then conducted to verify the theoretical findings.
Lei, G, Li, Y, Liu, C, Ma, B, Guo, Y & Zhu, J 1970, 'Application-oriented design optimization of flux-switching PM motors', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. Flux-switching permanent magnet machines (FSPMMs) have been investigated for hybrid electric vehicles (HEVs). This paper presents an optimal FSPMM with 12 stator poles to meet the minimal performance specifications required by the drive machine in the 2010 Prius HEV. After a qualitative analysis based on size equation to briefly compare performances of FSPMMs with four rotor topology structures, a quantitative analysis method based on multilevel optimization method and finite element analysis model is presented to obtain an accurate performance comparison. It is found that FSPMMs with different topology structures have different optimal structural parameters, and the optimal one with 13 rotor poles has the best performances in terms of output power and efficiency among four different rotor structures. The proposed method can be employed as an accurate design optimization and comparison method for FSPMMs with different topology structures and highly dimensional structural optimization parameters.
Li, A, Li, Y, Zhang, C, Yang, Q & Zhu, J 1970, 'Design of a novel high frequency 2-D magnetic tester with nanocrystalline material', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. The rotating magnetic properties of nanocrystalline materials at high frequencies play an important role in design and optimization of high frequency transformers with large capacity and high performance. In this paper, a novel high frequency rotating magnetic properties tester is designed, which is applied to measure the high frequency rotating magnetic properties of nanocrystalline materials. By changing the shape of the core, a new magnetic circuit structure is designed, which reduces the difficulty in assembly of the magnetic cores and improves the stability of the test system. A layer winding with copper foil is designed to ensure the accurate simulation of the high frequency rotating magnetic field. The influence of sample size and winding position on excitation effect is analyzed by finite element simulation. The magnetic circuit structure is optimized and the feasibility of the scheme is verified.
Li, H, Wang, TQ, Huang, X & Zhang, JA 1970, 'Low-Complexity Uplink Multiuser Receivers for MIMO System with Massive Hybrid Array', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. Due to the enormous needs for signal processing and hardware constraints, the full digital implementation for a large antenna array at mmWave frequencies becomes intractable. Hence, receiver design for MIMO system with massive hybrid array is very demanding, particularly for subarray structure. In this paper, we propose two low- complexity uplink multiuser receiver design schemes (single-beam and multi-beam) under the circumstances of only users' angles of arrival (AOAs) available at base station, which greatly simplify the analog beamforming structure and reduce the complexity of channel estimation especially when the number of antenna elements is considerably large. In the single-beam scheme, subarrays are mapped to different users one by one such that each subarray serves a specific user. In the multibeam scheme, all subarrays use the same analog beamforming and any subarray's beamforming signal potentially points at all users. Digital beamforming is then employed to combine all subarray signals followed by equalization. Simulations are performed to compare the proposed schemes with other schemes that need channel information available at the subarray output. Since only AOAs are required for analog and digital beamformings, the proposed schemes are more suitable for mmWave MIMO system with massive hybrid array in spite of slight sum-rate loss.
Li, H, Yuan, D, Wang, S, Wang, S & Zhu, J 1970, 'Core losses calculation of nanocrystalline alloy high frequency transformer considering magnetic hysteresis effects', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. Core losses of nanocrystalline alloy high frequency transformer (HFT) are calculated by adopting the finite element method with magnetic hysteresis effects considered. A normal Preisach model is used to represent the magnetic hysteresis during the numerical simulation. The normal Preisach model features with simple formulations and easy parameters identification. A dynamic circuit model of laminated magnetic cores for high frequency operation is used to calculate the core losses. Results are compared between the finite element method (FEM) and magnetic circuit method to prove the accuracy of finite element method, and it also provides a more accuracy way and general to compute the core loss of magnetic cores.
Li, K, Ni, W, Duan, L, Abolhasan, M & Niu, J 1970, 'SWPT: A Joint-Scheduling Model for Wireless Powered Sensor Networks', GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017 IEEE Global Communications Conference (GLOBECOM 2017), IEEE, Singapore, Singapore, pp. 1-6.
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© 2017 IEEE. In a rechargeable wireless sensor network, the data packets are generated by sensor nodes at a specific data rate, and transmitted to a base station. Moreover, the base station transfers power to the nodes by using Wireless Power Transfer (WPT) to extend their battery life. However, inadequately scheduling WPT and data collection causes some of the nodes to drain their battery and have their data buffer overflow, while the others waste their harvested energy, which is more than they need to transmit their packets. In this paper, we investigate a novel optimal scheduling strategy, called Scheduled WPT (SWPT), aiming to minimize data packet loss from a network of wireless powered sensor nodes by jointly considering the sensor nodes' energy consumption and data queue state information. The scheduling problem is formulated by a MDP model, assuming that the complete states of each sensor node are well known by the base station. This presents the best effort performance of the scheduling that can be collected in a wireless powered sensor network. The simulation results show that, in terms of network throughput and packet loss rate, the proposed scheduling model significantly improves the network performance.
Li, M, Liu, Y, Chen, S-L, Qin, P-Y & Guo, YJ 1970, 'Low sidelobe synthesis of dipole arrays by element orientation selection using binary codec genetic algorithm', 2017 11th European Conference on Antennas and Propagation (EUCAP), 2017 11th European Conference on Antennas and Propagation (EUCAP), IEEE, Paris, France, France, pp. 2838-2840.
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© 2017 Euraap. Selecting appropriate element orientations can significantly reduce the sidelobe level of the antenna array. In this paper, a binary coded genetic algorithm (BCGA) which selects the element orientations from specified discrete angles, is proposed to reduce the sidelobe level (SLL) of the array. Compared to the conventional GA, the BCGA is much faster in this application. Synthesis results show the effectiveness and efficiency of the proposed method.
Li, N, Zhu, J, Lin, M, Yang, G & Kong, Y 1970, 'Flux-weakening performance of series permanent magnet memory machine', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. This paper presents the theoretical analysis of flux-weakening performance of series permanent magnet (SPM) memory machine. A modified circle diagram is proposed to graphically illustrate the maximum torque per voltage (MTPV) flux-weakening control strategy for the memory machine. It is shown that a maximum torque capacity can be obtained by controlling the armature current and magnet flux simultaneously. The influence of machine parameters on the performance of PM memory machine is also investigated. The results can be used to design a PM memory machine for a given flux-weakening performance.
Li, Q, Tan, Z, Jamdagni, A, Nanda, P, He, X & Han, W 1970, 'An intrusion detection system based on polynomial feature correlation analysis', Proceedings - 16th IEEE International Conference on Trust, Security and Privacy in Computing and Communications, 11th IEEE International Conference on Big Data Science and Engineering and 14th IEEE International Conference on Embedded Software and Systems, Trustcom/BigDataSE/ICESS 2017, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, Sydney, pp. 978-983.
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© 2017 IEEE. This paper proposes an anomaly-based Intrusion Detection System (IDS), which flags anomalous network traffic with a distance-based classifier. A polynomial approach was designed and applied in this work to extract hidden correlations from traffic related statistics in order to provide distinguishing features for detection. The proposed IDS was evaluated using the well-known KDD Cup 99 data set. Evaluation results show that the proposed system achieved better detection rates on KDD Cup 99 data set in comparison with another two state-of-the-art detection schemes. Moreover, the computational complexity of the system has been analysed in this paper and shows similar to the two state-of-the-art schemes.
Li, W, Ni, W, Liu, D, Liu, RP, Wang, P & Luo, S 1970, 'Fine-Grained Access Control for Personal Health Records in Cloud Computing', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, NSW, Australia, pp. 1-5.
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© 2017 IEEE. This paper presents a novel access control scheme for personal health record(PHR) data in cloud computing. The scheme utilizes attribute-based encryption(ABE), hash function and symmetric encryption to realize a fine-grained, multi- privilege access control to PHR. The patients can share their PHR with medical staff from various departments with different privileges securely. The experimental results show the efficiency of our scheme in terms of running-time, communication cost and storage overhead.
Li, Y, Zhu, L & Zhu, J 1970, 'Calculation of core losses under DC bias and harmonics based on Jiles-Atherton dynamic hysteresis model combined with finite element analysis', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. This paper presents a method to calculate the core losses in SiFe laminations under magnetizations with DC bias and harmonics. DC bias is usually generated by the ground return current of high voltage direct current (HVDC) system intrude into the windings of neutral-grounded transformers, which leads to increase of harmonics and core loss. For accurate calculation of core losses under DC bias, the Jiles-Atherton (J-A) dynamic hysteresis model is incorporated into the finite element method. The J-A dynamic hysteresis model is constructed by combining the traditional J-A hysteresis model with the models of instantaneous eddy current and excess losses. To account for the DC bias, the J-A dynamic model was modified by adjusting the parameters of instantaneous excess loss model. The theoretical results are verified by the measured results by a Single-Sheet Tester (SST 500).
Lin, S, Yu, J, Ni, W & Liu, R 1970, 'Radio Resource Management for Ultra-Dense Smallcell Networks: A Hybrid Spectrum Reuse Approach', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, NSW, Australia, pp. 1-7.
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© 2017 IEEE. Smallcells have great potential to enhance cellular networks, complementing macrocells. Severe interference may occur, as smallcells are expected to be deployed and operated uncoordinatedly. However, existing resource management methods require significant overhead to suppress interference. We propose a new resource management approach which is able to mitigate the cross-tier and co-tier interference with substantially reduced overhead. The key idea is to categorize the smallcells into two regions based on a judiciously designed cross-tier interference criterion. Smallcells in the high-interference zone occupy orthogonal radio resources with the macrocell; smallcells in the other zone can reuse the resources that the macrocell is using. Another crucial aspect is that we formulate the resource sharing between the macrocell and smallcells in the low-interference zone to a multi-agent Q-learning process which assigns adequate transmit power levels in a decentralized manner to suppress the co/cross-tier interference. As a result, our approach is able to reduce the outage probabilities of macrocell users significantly to 0%, respectively, in a dense smallcell deployment (200 smallcells), as evidenced by simulation results.
Lin, S, Yu, J, Ni, W & Liu, RP 1970, 'A Decoupled 5G Network Control Framework: Distributed Adaptation and Centralized Coordination', 2017 IEEE Globecom Workshops (GC Wkshps), 2017 IEEE Globecom Workshops (GC Wkshps), IEEE, Singapore, Singapore, pp. 1-6.
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© 2017 IEEE. A promising and cost-e ective way to connect massively and densely deployed 5G smallcells is through existing Internet infrastructure. However, severe delays of hundreds of milliseconds over Internet and signi cantly increased complexity due to massive networks impose critical challenges to 5G network control. Traditional centralized network control can neither cope with such delays nor scale to massive networks. Excessive inter-smallcell interfer- ence would occur. We introduce a new 5G network control structure which is tolerant to the severe delay and massive network scale. The key idea is to decouple delay-sensitive power control from the delay-tolerant channel assignment. The delay-sensitive power control can be decentralized, and formulated as a non-cooperative game. As a result, timely control with stringent delay requirements is eliminated. The delay-tolerant channel assignment is modelled as an evolutionary clustering game, so that the control complex- ity can be distributed among the smallcells and becomes practically acceptable. Performance studies show that the new decoupled 5G network control is e ective for timely interference mitigation. The stability and scalability of the new 5G network control are also demonstrated.
Liu, C, Ma, B, Lei, G, Guo, Y, Wang, Y & Zhu, J 1970, 'Development of a new low cost transverse flux-flux switching permanent magnet machine with soft magnetic composite cores and ferrite magnets', 2017 IEEE International Magnetics Conference (INTERMAG), 2017 IEEE International Magnetics Conference (INTERMAG), IEEE, Dublin, Ireland.
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© 2017 IEEE. Soft magnetic composite (SMC) material is a new soft magnetic material, now it is popular in the designing of permanent magnet machine where high operation frequency and 3-D flux path required, due to its advantages of low eddy current loss and magnetic isotropy.
Liu, C, Wang, Y, Lei, G, Ma, B, Guo, Y & Zhu, J 1970, 'Manufacturing processes of soft magnetic composite cores for permanent magnet machines', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. By using the low mass density compaction, the electrical machine with soft magnetic composite (SMC) cores has shown its great advantage of the low manufacturing cost over that with silicon steels, especially in the mass production. For the laboratory prototype, wire cutting method is widely used to build the SMC cores for electrical machine. However, cutting the SMC preform block can destroy the magnetic properties of the SMC material, making that the electrical machine made in the laboratory cannot have the same performance as that in the mass production. To minimize the gap between the laboratory prototype and the mass production, the SMC cores should be made by the die compaction. However, to achieve high mass density, the compact pressure must be high and the productivity is low. On the other hand, low mass density compaction would greatly increase the productivity, but the core performance may deteriorate, which can be dealt with careful design and optimization of electrical machine. This paper presents our recent investigation on the manufacturing process of soft magnetic cores. The details of designing the die tools and building the SMC cores by using these tools are described.
Liu, C, Wang, Y, Lei, G, Ma, B, Guo, Y & Zhu, J 1970, 'Parameter analysis of a new AFIPM for light electric vehicle application', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. The electrical machines are gaining more and more attentions nowadays, especially for the electric vehicle application. Compared with the radial flux machine, the axial flux machine can have higher torque density and efficiency due to its tight structure. However, most of the axial flux machines are designed with the surface mounted permanent magnets (PMs) rotor, where the reluctance torque ability is reduced. To improve the torque ability of the axial flux machine, a new axial flux interior permanent magnet machine (AFIPM) is proposed and analyzed in this paper. The rotor of the proposed AFIPM is manufactured by the rolling the electrical steels as a ring core, then the PMs are inserted in the holes of the rotor ring, the axial side of the rotor ring is designed with the several different steps to eliminate the harmonics of the back EMF as well. The static performance and electromagnetic parameters of the AFIPM is calculated and it shows that the reluctance torque ability of the AFIPM is very good, based on the 3D finite element method (FEM) and frozen magnetic permeability technology.
Liu, J, Hossain, MJ & Lu, J 1970, 'Switching Performance Optimization for a Hybrid AC/DC Microgrid using an Improved VSG Control Strategy', 2017 IEEE INNOVATIVE SMART GRID TECHNOLOGIES - ASIA (ISGT-ASIA), 7th IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), IEEE, Univ Auckland, Auckland, NEW ZEALAND, pp. 72-76.
Liu, J, Hossain, MJ & Lu, J 1970, 'Switching performance optimization for a hybrid AC/DC microgrid using an improved VSG control strategy', 2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), 2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), IEEE, pp. 1-5.
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© 2017 IEEE. The hybrid AC/DC microgrid gains a great attention in recent years as it can improve the energy efficiency and ensure the reliability of the system. This paper makes an investigation on the operation mode switching performance of an AC/DC combined hybrid microgrid based on a real system at Griffith University, Queensland, Australia. An improved virtual synchronous generator (VSG) control strategy is developed to optimize the switching performance from the grid-tied mode to the islanding mode. The basic VSG principle is described and the improved VSG model is introduced. Based on the improved model, a pre-synchronization method is proposed. Comparison of the microgrid performance between conventional droop control and the improved VSG control is carried out by simulation on Matlab/SIMULINK environment. Simulation results show the advantage of VSG control strategy and the validity of the pre-synchronization method.
Lovatt, HC, Watterson, PA, Schroth, JG, Perry, TA & de Vries, L 1970, 'Non-rotating high-accuracy iron loss measurements on motor stator stacks', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-5.
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A new and improved technique is presented for the measurement of iron loss in motor stators. The most accurate existing technique rotates dummy-test rotors, one for each field strength of interest, inside the stators to be tested and measures the reaction torque on the stators. The new technique uses a wound `rotor' component that does not rotate mechanically but does rotate electrically. Therefore, the speed and magnitude of the rotating flux can be controlled electrically without the inherent difficulties of rotating mechanically at high speed and without building different dummy-test rotors for each field strength test
Lu, DD-C 1970, 'Comparison of DC/DC converters in DCM for reducing low-frequency input current ripple of single-phase two-stage inverters', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. Single-phase two-stage inverters generally use an intermediate capacitor to buffer the power imbalance between DC input and AC output. However, the resultant low-frequency voltage ripple on this intermediate capacitor may produce low-frequency ripple at the source side, especially when the front-end dc/dc converter operates in continuous conduction mode (CCM). Some common solutions to reducing this ripple are feedforward control and power decoupling circuits. Alternatively, this paper analyzes a two-stage inverter where the front-end is a dc/dc converter operating in discontinuous conduction mode (DCM). In general dc/dc converters operating in DCM have inherent natural capability to reduce this low-frequency input current ripple, without needing a sophisticated control or complex circuitry as compared with its CCM operation. Analysis with simulation verification is reported to demonstrate such capability.
Ly Ha, VK, Chai, R & Nguyen, HT 1970, 'Real-time WebRTC-based design for a telepresence wheelchair', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Jeju Island, Korea, pp. 2676-2679.
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This paper presents a novel approach to the
telepresence wheelchair system which is capable of real-time
video communication and remote interaction. The investigation
of this emerging technology aims at providing a low-cost and
efficient way for assisted-living of people with disabilities. The
proposed system has been designed and developed by deploying
the JavaScript with Hyper Text Markup Language 5 (HTML5)
and Web Real-time Communication (WebRTC) in which the
adaptive rate control algorithm for video transmission is
invoked. We conducted experiments in real-world
environments, and the wheelchair was controlled from a
distance using the Internet browser to compare with existing
methods. The results show that the adaptively encoded video
streaming rate matches the available bandwidth. The video
streaming is high-quality with approximately 30 frames per
second (fps) and round trip time less than 20 milliseconds (ms).
These performance results confirm that the WebRTC approach
is a potential method for developing a telepresence wheelchair
system.
Ly, QT, Handojoseno, AMA, Gilat, M, Chai, R, Ehgoetz Martens, KA, Georgiades, M, Naik, GR, Tran, Y, Lewis, SJG & Nguyen, HT 1970, 'Detection of gait initiation Failure in Parkinson's disease based on wavelet transform and Support Vector Machine', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Jeju Island, Korea, pp. 3048-3051.
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© 2017 IEEE. Gait initiation Failure (GIF) is the situation in which patients with Parkinson's disease (PD) feel as if their feet get 'stuck' to the floor when initiating their first steps. GIF is a subtype of Freezing of Gait (FOG) and often leads to falls and related injuries. Understanding of neurobiological mechanisms underlying GIF has been limited by difficulties in eliciting and objectively characterizing such gait phenomena in the clinical setting. Studies investigating the effects of GIF on brain activity using EEG offer the potential to study such behavior. In this preliminary study, we present a novel methodology where wavelet transform was used for feature extraction and Support Vector Machine for classifying GIF events in five patients with PD and FOG. To deal with the large amount of EEG data, a Principal Component Analysis (PCA) was applied to reduce the data dimension from 15 EEG channels into 6 principal components (PCs), retaining 93% of the information. Independent Component Analysis using Entropy Bound Minimization (ICA-EBM) was applied to 6 PCs for source separation with the aim of improving detection ability of GIF events as compared to the normal initiation of gait (Good Starts). The results of this analysis demonstrated the correct identification of GIF episodes with an 83.1% sensitivity, 89.5% specificity and 86.3% accuracy. These results suggest that our proposed methodology is a promising non-invasive approach to improve GIF detection in PD and FOG.
Ly, QT, Handojoseno, AMA, Gilat, M, Chai, R, Ehgoetz Martens, KA, Georgiades, M, Naik, GR, Tran, Y, Lewis, SJG & Nguyen, HT 1970, 'Detection of turning freeze in Parkinson's disease based on S-transform decomposition of EEG signals', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Jeju Island, Korea, pp. 3044-3047.
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© 2017 IEEE. Freezing of Gait (FOG) is a highly debilitating and poorly understood symptom of Parkinson's disease (PD), causing severe immobility and decreased quality of life. Turning Freezing (TF) is known as the most common sub-type of FOG, also causing the highest rate of falls in PD patients. During a TF, the feet of PD patients appear to become stuck whilst making a turn. This paper presents an electroencephalography (EEG) based classification method for detecting turning freezing episodes in six PD patients during Timed Up and Go Task experiments. Since EEG signals have a time-variant nature, time-frequency Stockwell Transform (S-Transform) techniques were used for feature extraction. The EEG sources were separated by means of independent component analysis using entropy bound minimization (ICA-EBM). The distinctive frequency-based features of selected independent components of EEG were extracted and classified using Bayesian Neural Networks. The classification demonstrated a high sensitivity of 84.2%, a specificity of 88.0% and an accuracy of 86.2% for detecting TF. These promising results pave the way for the development of a real-time device for detecting different sub-types of FOG during ambulation.
Ma, B, Lei, G & Zhu, J 1970, 'Design, manufacturing and optimization of PM-SMC motors', 2017 7th International Electric Drives Production Conference (EDPC), 2017 7th International Electric Drives Production Conference (EDPC), IEEE, Würzburg, Germany, pp. 1-6.
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© 2017 IEEE. Soft magnetic composite (SMC), as a relatively new magnetic material, has attracted much attention in the design of electrical machines. This paper aims to discuss the specific and common problems in the design of permanent magnet (PM) motors with SMC cores. Firstly, the motor topology design is introduced for taking advantage of the SMC properties. Then, precise material testing and modeling methods are presented for the accurate core loss calculation of PM-SMC motors. Considering the influence of manufacturing process, two design optimization approaches are utilized for enhancing the motor performance. For improving the electromagnetic properties of the SMC cores, the orthogonal experiment is proposed for investigating and optimizing the heat treatment process. Considering the manufacturing tolerances in the actual production, the robust tolerance design optimization approach is introduced for pursuing the optimal motor performance and manufacturing cost with high reliability.
Mahmud, K, Morsalin, S, Hossain, MJ & Town, GE 1970, 'Domestic peak-load management including vehicle-to-grid and battery storage unit using an artificial neural network', 2017 IEEE International Conference on Industrial Technology (ICIT), 2017 IEEE International Conference on Industrial Technology (ICIT), IEEE, Toronto, CANADA, pp. 586-591.
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Mahmud, K, Town, GE & Hossain, MJ 1970, 'Mitigating the impact of rapid changes in photovoltaic power generation on network voltage', 2017 IEEE Power and Energy Conference at Illinois (PECI), 2017 IEEE Power and Energy Conference at Illinois (PECI), IEEE, Champaign, IL.
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Mai, TC, Hoang, TM, Tuan, HD, Di Renzo, M & Duong, TQ 1970, 'Modeling and Analysis of Interference for Diffusion-Based Nanoscale Networks with Spatially Distributed Transmitters', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, NSW, Australia, pp. 1-5.
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© 2017 IEEE. We consider a diffusion-based nano-network with N spatially distributed transmitters and one receiver. While the transmitters are linked in a unified entity to perform one transmission, the receiver is large enough to be viewed as a plane. Messages are encoded into the number of nano-scale molecules. Based on these assumptions, we analyze the signal-to-interference ratio, which is based on the average numbers of absorbed molecules. Moreover, we present an approach to interference alignment for molecular communications.
Maung, HM, Aramvith, S & Miyanaga, Y 1970, 'Error resilience aware rate control and mode selection for HEVC video transmission', 2017 IEEE International Conference on Consumer Electronics (ICCE), 2017 IEEE International Conference on Consumer Electronics (ICCE), IEEE.
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Men, X, Guo, Y, Wu, G, Shi, C & Zhu, J 1970, 'Implementation of a motor control system for electric bus based on DSP', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. Motor control system may be the most important part of electric vehicles. To implement the control strategies, a lot of practical problems need to be taken into account. In this paper, an induction motor control system for electric bus is developed based on digital signal processor (DSP). The control strategy is based on field-oriented control and space vector pulse width modulation. Over-modulation, field weakening control, PI controller and fault diagnosis are also applied in this DSP algorithm. As a practical product running on a real electric bus with an 100 kW induction motor, communication with vehicle control unit (VCU) by controller area network (CAN bus), control system safety and PC software designed for experiment at lab are also discussed. The transient and steady-state performances of this motor control system are analyzed by experiments. Its performance is satisfactory when applied to the real electric bus.
Miyanaga, Y, Tsutsui, H & Imagawa, T 1970, 'FHD loss-less video communication over 8 × 8 MIMO-OFDM', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE.
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Morshed, KM, Karmokar, DK & Esselle, KP 1970, 'Highly Efficient Leaky-Wave Antenna Array for 28-GHz Millimeter-Wave Terminals', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, NSW, Australia, pp. 1-4.
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© 2017 IEEE. A highly efficient leaky-wave antenna (LWA) array is presented in this paper. The proposed LWA array covers 28-GHz millimeter-wave frequency band and can be useful for 5G terminals. The antenna has been designed to be integrated to a substrate of dimensions 120 mm × 70 mm and occupies a small area of 24.5 mm × 24.5 mm. A dielectric load is used to increase the antenna efficiency. The efficiency of the array varies between 97% and 98% within the 28-GHz millimeter-wave band. It has a wide operating bandwidth of 6 GHz (26 - 32 GHz) and a peak gain of 9.1 dBi at 28 GHz. Within the 28-GHz millimeter-wave band the proposed LWA array has stable boresight radiation in the x-z and y-z planes.
Movassaghi, S, Maleki, B, Smith, DB & Abolhasan, M 1970, 'Biologically inspired self-organization and node-level interference mitigation amongst multiple coexisting wireless body area networks', 2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC), 2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC), IEEE, Valencia, Spain, pp. 1221-1226.
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© 2017 IEEE. This paper presents a node-level self-organizing interference avoidance scheme (SIAC) between multiple coexisting wireless body area networks (WBANs) that incorporates self-organization and smart spectrum allocation. It follows a biologically inspired approach based on the theory of pulse-coupled oscillators for self-organization. The proposed scheme makes three major contributions as compared to the current literature. Firstly, it considers node-level interference for internetwork interference mitigation rather than considering each WBAN as a whole. Secondly, it allocates synchronous and parallel transmission intervals for interference avoidance in an optimal manner and dynamically adapts to changes in their coexistence. Finally, it achieves collision-free, self-organized communication with only information of the firing signal of each WBAN and does not require a global coordinator to manage its communications. It operates on a nodes traffic priority, signal strength, and density of sensors in a WBAN. Simulation results show that our proposal achieves a fast convergence time despite the little information it receives. Moreover, SIAC is shown to be robust to variations in signal strength, number of coexisting WBANs and number of sensor nodes within each WBAN.
Mufungulwa, G, Tsutsui, H, Miyanaga, Y, Abe, S-I & Ochi, M 1970, 'Robust speech recognition for similar Japanese pronunciation phrases under noisy conditions', 2017 International Symposium on Signals, Circuits and Systems (ISSCS), 2017 International Symposium on Signals, Circuits and Systems (ISSCS), IEEE.
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Mukhtar, NM & Dah-Chuan Lu, D 1970, 'A bidirectional flyback converter with cross-coupled non-dissipative snubber circuits', 2017 IEEE International Telecommunications Energy Conference (INTELEC), 2017 IEEE International Telecommunications Energy Conference (INTELEC), IEEE, Broadbeach, QLD, Australia, pp. 476-481.
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This paper proposed a novel isolated bidirectional flyback converter integrated with two non-dissipative LC snubbers. In the proposed topology, the main flyback transformer and the LC snubbers are crossed-coupled to reduce current circulation and recycle the leakage energy. The proposed isolated bidirectional flyback converter can step-up the voltage of the battery (Vbat = 12V) to a high voltage side (VHV = 200V) for the load demand and vice versa. The main goal of this paper is to demonstrate the performances of this topology to achieve high voltage gain with less switching losses and reduce components stresses. The circuit analysis conferred in detail for Continuous Conduction Mode (CCM). Lastly, a laboratory prototype constructed to compare with simulation result.
Mukunthan, A, Cooper, CS, Safaei, F, Franklin, DR & Abolhasan, M 1970, 'Leveraging the Propagation Model to Make Greedy Routing Decisions in Urban Environments.', VTC Spring, IEEE Vehicular Technology Conference, IEEE, Sydney, NSW, Australia, pp. 1-6.
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© 2017 IEEE. The CORNER propagation model, first proposed in 2010, has been previously validated and found to be a reasonably accurate representation of propagation scenarios in urban Vehicular Ad Hoc Networks (VANETs). This paper considers the impact of the propagation environment on routing performance and reveals a pressing need to consider more accurate propagation models when designing urban VANET routing protocols. A greedy routing protocol, which uses CORNER's propagation estimates for neighbour selection, is then presented. The new protocol, named Corner Propagation Stateless Routing (CPSR) is compared to GPSR, a benchmark protocol for VANETs, showing between 87% and 300% improvement in packet delivery ratio at higher network loads.
Nagar, U, Nanda, P, He, X & Tan, ZT 1970, 'A framework for data security in cloud using collaborative intrusion detection scheme', Proceedings of the 10th International Conference on Security of Information and Networks, SIN '17: Security of Information and Networks, ACM, Jaipur, India, pp. 188-193.
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© 2017 Association for Computing Machinery. Cloud computing offers an on demand, elastic, global network access to a shared pool of resources that can be configured on user demand. The advantages of cloud computing are lucrative for well-established organizations looking to reduce infrastructure cost overheads. However, the users are not quite confident in entrusting their data to the cloud due to security threats and risks perceived in the cloud domain. Issues involving privacy requirements for the cloud and best practices in the cloud are suggested in this paper. Although the cloud provider ensures security in the cloud yet the flow of data, storage location, data computing process and security breaches are not transparent to the cloud customer. This distrust and lack of control on data is a major hindrance for potential cloud customers in adopting the cloud models for their businesses. Intrusion Detection Systems (IDSs) are widely used to detect malicious activities. However existing solutions with IDSs involving DDoS and other non-detectable events may not be suitable in applying to the cloud due to distributed data storage and a major shift in Internet access mechanisms offered by cloud providers. Hence there is a strong need to analyze an appropriate IDS to counter DDoS attacks in the cloud. In this paper we propose a novel framework for data security in the cloud using Collaborative Intrusion Detection (CIDS) scheme. The benefits of CIDS scheme in cloud are enabling the end user to get comprehensive information in the event of a distributed attack on cloud.
Naik, GR, Pratihast, M, Chai, R, Al-Ani, A, Acharyya, A & Nguyen, HT 1970, 'Differences in lower limb muscle activation patterns during Sit to Stand Task for different heel heights', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Jeju Island, Korea, pp. 2486-2489.
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The purpose of this study was to investigate
differences in lower limb muscle activation patterns for females
wearing shoes with different heel heights during Sit to Stand
Task (STS). Ten female participants with no prior history of
neurological disorders participated in this study. Surface
electromyography (sEMG) characteristics were recorded for
four different heel heights (ranging from 4cm to 10cm) while
performing the STS task. Signal processing analysis suggests
that muscle activities increases on elevated heel heights, which
may induce muscle imbalance for frequent STS tasks. In
addition, results of muscle utilisation (percentage) for different
heel heights suggest that lower limb muscles tend to compensate
in order to maintain postural balance.
Najjar, A, Kaneko, S & Miyanaga, Y 1970, 'Combining satellite imagery and open data to map road safety', 31st AAAI Conference on Artificial Intelligence, AAAI 2017, pp. 4524-4530.
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Improving road safety is critical for the sustainable development of cities. A road safety map is a powerful tool that can help prevent future traffic accidents. However, accurate mapping requires accurate data collection, which is both expensive and labor intensive. Satellite imagery is increasingly becoming abundant, higher in resolution and affordable. Given the recent successes deep learning has achieved in the visual recognition field, we are interested in investigating whether it is possible to use deep learning to accurately predict road safety directly from raw satellite imagery. To this end, we propose a deep learning-based mapping approach that leverages open data to learn from raw satellite imagery robust deep models able to predict accurate city-scale road safety maps at an affordable cost. To empirically validate the proposed approach, we trained a deep model on satellite images obtained from over 647 thousand traffic-accident reports collected over a period of four years by the New York city Police Department. The best model predicted road safety from raw satellite imagery with an accuracy of 78%. We also used the New York city model to predict for the city of Denver a city-scale map indicating road safety in three levels. Compared to a map made from three years' worth of data collected by the Denver city Police Department, the map predicted from raw satellite imagery has an accuracy of 73%.
Nan, Y, Huang, X & Guo, YJ 1970, 'A Generalized Continuous Wave Synthetic Aperture Radar', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. Attention has been devoted to Synthetic Aperture Radar (SAR) for half a century. Though it is a well-proven remote sensing technique, conventional pulsed SAR has several inherent limitations. In this paper, we present a new SAR concept, called Generalized Continuous Wave SAR (GCW-SAR). By using continuous wave signaling, the GCW-SAR system achieves better performance and overcomes the limitations such as the minimum antenna area in conventional SAR. Unlike the frequency modulated continuous wave SAR (FMCW-SAR) system, the GCW-SAR image is reconstructed by correlation between the sampled raw data and the location dependent reference signals. A fast image reconstruction algorithm is also presented in the paper. The principle of GCW-SAR and the effectiveness of the proposed algorithm are validated by numerical simulation results.
Nan, Y, Huang, X & Guo, YJ 1970, 'Passive synthetic aperture radar imaging with piecewise constant Doppler algorithm', 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Veorna, Italy, pp. 41-44.
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© 2017 IEEE. This paper presents a non-cooperative space-surface bistatic synthetic aperture radar (SS-BSAR) with a novel image reconstruction algorithm. Exploiting the continuous wave signal from the transmitters of opportunity, the new algorithm produces better imaging performance. Unlike the conventional passive SAR, the image reconstruction is achieved by correlation in time-domain without distinction between fast time and slow time. With the movement of the radar, the range curve can be linearized within multiple segments. In each segment, the Doppler frequency shift incurred in the reflected signal from a target can be assumed to be constant and thus the SAR image can be reconstructed recursively. The proposed piecewise constant Doppler (PCD) algorithm is validated by the simulation results.
Nanda, A, Nanda, P & He, X 1970, 'Geo-location oriented routing protocol for smart dynamic mesh network', Proceedings - 18th IEEE International Conference on High Performance Computing and Communications, 14th IEEE International Conference on Smart City and 2nd IEEE International Conference on Data Science and Systems, HPCC/SmartCity/DSS 2016, 2016 IEEE 18th International Conference on High Performance Computing and Communications; IEEE 14th International Conference on Smart City; IEEE 2nd International Conference on Data Science and Systems (HPCC/SmartCity/DSS), IEEE, Sydney, Australia, pp. 891-898.
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© 2016 IEEE. Wireless Mesh Network is an emerging technology with great potential to become a Self-Sustained Network. Unlike the traditional networks that dominate the current communication system and rely on a large and expensive setup of wired/wireless access points to provide connection between users, the Wireless Mesh Network is formed by the user devices (referred as Nodes) which connect to each other to form a network. However, due to the use of legacy/traditional network models for mesh networks, there exist various limitations towards its implementation. This paper presents a new approach towards the Wireless Mesh Network, incorporating a new routing scheme based on the Geo-Location of the devices. It puts forward the structure, working principle and its performance during the first implementation.
Nanda, A, Nanda, P, He, X, Jamdagni, A & Puthal, D 1970, 'Secure-GLOR: An adaptive secure routing protocol for dynamic wireless mesh networks', Proceedings - 16th IEEE International Conference on Trust, Security and Privacy in Computing and Communications, 11th IEEE International Conference on Big Data Science and Engineering and 14th IEEE International Conference on Embedded Software and Systems, Trustcom/BigDataSE/ICESS 2017, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, Sydney, Australia, pp. 269-276.
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© 2017 IEEE. With the dawn of a new era, digital security has become one of the most essential part of any network. Be it a physical network, virtual network or social network, the demand for secure data transmission is ever increasing. Wireless mesh networks also stand the same test of security as the legacy networks. This paper presents a secure version of the Geo-Location Oriented Routing (GLOR) protocol for wireless mesh networks, incorporating a multilevel security framework. It implements authentication using the new features of the network model and enables encryption throughout the network to provide high levels of security.
Nanda, P, Xiang, Y & Mu, Y 1970, 'Message from the IEEE TrustCom 2017 Program Chairs', Proceedings - 16th IEEE International Conference on Trust, Security and Privacy in Computing and Communications, 11th IEEE International Conference on Big Data Science and Engineering and 14th IEEE International Conference on Embedded Software and Systems, Trustcom/BigDataSE/ICESS 2017, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, p. xvii.
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Ngo, QT & Dang, DNM 1970, 'A Dynamic Cooperative MAC Protocol for Vehicular Ad-hoc Networks', Springer International Publishing, pp. 780-790.
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Nguyen, KK, Hoang, DT, Niyato, D, Wang, P, Nguyen, D & Dutkiewicz, E 1970, 'Cyberattack Detection in Mobile Cloud Computing: A Deep Learning Approach', IEEE Wireless Communications and Networking Conference, WCNC, IEEE Wireless Communications and Networking Conference (WCNC), Barcelona, Spain, pp. 1-6.
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With the rapid growth of mobile applications and cloud computing, mobilecloud computing has attracted great interest from both academia and industry.However, mobile cloud applications are facing security issues such as dataintegrity, users' confidentiality, and service availability. A preventiveapproach to such problems is to detect and isolate cyber threats before theycan cause serious impacts to the mobile cloud computing system. In this paper,we propose a novel framework that leverages a deep learning approach to detectcyberattacks in mobile cloud environment. Through experimental results, we showthat our proposed framework not only recognizes diverse cyberattacks, but alsoachieves a high accuracy (up to 97.11%) in detecting the attacks. Furthermore,we present the comparisons with current machine learning-based approaches todemonstrate the effectiveness of our proposed solution.
Nguyen, LD, Tuan, HD, Duong, TQ & Poor, HV 1970, 'Beamforming and power allocation for energy-efficient massive MIMO', 2017 22nd International Conference on Digital Signal Processing (DSP), 2017 22nd International Conference on Digital Signal Processing (DSP), IEEE, London, UK, pp. 1-6.
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© 2017 IEEE. Massive multiple input multiple output (MIMO) has emerged as a promising technology, which utilizes a large number of antennas at base stations (BSs) to significantly improve the spectral efficiency in terms of bits/s/Hz while reducing the radiated signal power. A critical issue with massive MIMO is the costly circuit power consumption, which is proportional to the number of antennas. This paper develops low-complexity power allocation techniques to apply beamforming and to maximize the energy efficiency of massive MIMO while meeting users' quality-of-service requirements. Algorithms of low computational complexity with rapid convergence are proposed to solve for the optimal beamformer in this sense. Numerical examples are provided to show the merit of the proposed computational approach.
Nguyen, T, Hoang, D, Nguyen, D & Seneviratne, A 1970, 'Initial trust establishment for personal space IoT systems', 2017 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS), 2017 IEEE Conference on Computer Communications: Workshops (INFOCOM WKSHPS), IEEE, Atlanta, USA, pp. 784-789.
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© 2017 IEEE. Increasingly, trust has played a crucial role in the security of an IoT system from its inception to the end of its lifecycle. A device has to earn some level of trust even before it is authenticated for admission to the system. Furthermore, once the device is admitted to the system, it may behave maliciously over time; hence its behavior must be evaluated constantly in the form of trust to ensure the integrity of the system. Currently, no mechanism exists to establish an initial trust on a device, without prior knowledge, before its admission to an IoT system. Even when trust is applicable, trust evaluation models require direct/indirect observations over time, historical data on past encounters, or third party recommendations. However, this type of past data is not available in the first encounter between the system and the device. The question is how to establish whether a device can be trusted to a level that merits further evaluation for admission into a mobile and dynamic IoT system when it encounters the system for the first time? This paper addresses this challenge by proposing a challenge-response method and a trust assessment model to establish, without prior knowledge, the initial trust that a device places on another in a mobile and dynamic environment called personal space IoT. The initial trust is established before further interaction can take place and under the assumption that only a limited window of time is available for the trust assessment. The paper describes and evaluates the proposed model theoretically and by simulation. It also describes a practical scheme for realizing the proposed solution.
Nguyen, TMC, Hoang, DB & Dat Dang, T 1970, 'Toward a programmable software-defined IoT architecture for sensor service provision on demand', 2017 27th International Telecommunication Networks and Applications Conference (ITNAC), 2017 27th International Telecommunication Networks and Applications Conference (ITNAC), IEEE, Mebourne, Australia, pp. 1-6.
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© 2017 IEEE. In the age of Internet of Things (IoT), sensors form a foundational component of IoT services, yet they are rigid with little capability for programmable configuration or reusability as they are application-specific, manufacturer-specific. Emerging IoT applications often deploy a vast number of sensors which may serve multiple applications. Programmability is thus essential but not found in legacy or current generation sensors. It is challenging to effectively utilize heterogeneity of resources to handle a large number of application demands. Software Defined Networking (SDN) and Network Function Virtualization (NFV) have proved effective paradigms for provisioning services on-demand and managing network functions and their life cycles. This paper proposes a software defined IoT architecture that captures the spirit of SDN and NFV where a software-defined Internet of Things (SD-IoT) controller can provide services as requested by an application and also manage heterogeneous physical sensors through their virtual representation called software-defined virtual sensor (SD-VSensor) autonomously. In particular, the paper presents the design of a streamline SD-IoT controller, a lightweight and reconfigurable SD-VSensor, and the communication protocol (S-MANAGE) between them. The proposed architecture enables heterogeneous application-specific WSN systems to be recognized and effectively utilized by diverse IoT applications under the orchestration of the SD-IoT controller. Moreover, heterogeneity of sensor nodes or IoT devices can be programmed to achieve sensor services on demand. The preliminary implementation results demonstrate the feasibility and efficiency of the proposed architecture.
Nguyen, V-D, Tuan, HD, Duong, TQ, Poor, HV & Shin, O-S 1970, 'Convex Quadratic Programming for Maximizing Sum Throughput in MIMO-NOMA Multicell Networks', GLOBECOM 2017 - 2017 IEEE Global Communications Conference, 2017 IEEE Global Communications Conference (GLOBECOM 2017), IEEE, Singapore, Singapore, pp. 1-6.
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© 2017 IEEE. This paper aims to design linear precoders for signal superposition at the base stations of non-orthogonal multiple access multiple-input multiple-output multi-cellular systems to maximize the overall sum throughput subject to the users' quality-of-service requirements, which are imposed independently on the users' channel conditions. This design problem is formulated as the maximization of a highly nonlinear and nonsmooth function subject to nonconvex constraints, which is very computationally challenging. A path-following algorithm for its solution, which invokes only a simple convex problem of moderate dimension at each iteration, is developed. Generating a sequence of improved points, this algorithm converges at least to a local optimum. Numerical results are then provided to demonstrate its merit.
Nizami, MSH & Hossain, J 1970, 'Optimal scheduling of electrical appliances and DER units for home energy management system', 2017 Australasian Universities Power Engineering Conference (AUPEC), 2017 Australasian Universities Power Engineering Conference (AUPEC), IEEE, Melbourne, AUSTRALIA.
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Pham, L, Irfansyah, AN, Hamilton, TJ & Lehmann, T 1970, 'The effect of source resistance on the linearity of Nauta structure OTA', 2017 IEEE 60th International Midwest Symposium on Circuits and Systems (MWSCAS), 2017 IEEE 60th International Midwest Symposium on Circuits and Systems (MWSCAS), IEEE, Tufts Univ, Medford Somerville Campus, Boston, MA, pp. 1208-1211.
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Pham, NH 1970, 'Direct storage hybrid (DSH) inverter: A new concept of intelligent hybrid inverter', 2017 IEEE Energy Conversion Congress and Exposition (ECCE), 2017 IEEE Energy Conversion Congress and Exposition (ECCE), IEEE, Cincinnati, OH, USA, pp. 5529-5536.
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This paper proposes a new configuration of a single-phase hybrid inverter with an integrated battery energy storage, which is suitable for residential households to maximize local consumption of solar energy and thus reduce dependency on grid support. The hybrid inverter is called Direct Storage Hybrid (DSH) Inverter. A transformer-less topology such as HERIC, operating at low frequency to generate a three-level rectangular output voltage, is adopted to connect a photovoltaic (PV) panel to the load and/or the grid. A series active filter is employed to compensate the high harmonic components from the rectangular voltage and provide a sinusoidal voltage. A bidirectional dc/dc converter connects the battery to the PV panel to control the battery state of charge (SoC) and optimize the PV panel operation during both off-grid and grid-connected modes. The DSH inverter can let the battery bypass the dc/dc converter and connect directly to the inverter stage, leading to a significant improvement in throughput efficiency in battery utilization. This paper discusses the operation and loss analysis of the DSH inverter in off-grid mode.
Pham, NH 1970, 'New design concept of a bidirectional wireless power transfer system using dual active bridge topology', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia.
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This paper proposes a new design concept of small air-gap bidirectional Wireless Power Transfer (WPT) system using Dual Active Bridge (DAB) topology. The wireless charging coils are considered as a weakly coupled transformer having relatively high leakage inductance, and thus the new design can obtain soft switching without implementing resonant capacitor or external inductor. This design has a simple construction and can enable bidirectional inductive power transfer with superior performance compared to the traditional large air-gap system. The new system can transfer high power via a compact coil structure thanks to smaller air gap. Moreover, soft-switching operation enables significant improvement in efficiency. The proposed design enables electrical vehicles and smart wheels to use batteries for supporting grid silently and seamlessly. This paper considers the application of smart wheel charger and presents an analytical design of the system using finite element analysis and circuit simulation. As a result, the design can achieve 97% efficiency at 3-kW, 85-kHz operation.
Pham, TT, Nguyen, DN, Dutkiewicz, E, McEwan, AL & Leong, PHW 1970, 'An anomaly detection technique in wearable wireless monitoring systems for studies of gait freezing in Parkinson's disease', 2017 International Conference on Information Networking (ICOIN), 2017 International Conference on Information Networking (ICOIN), IEEE, Da Nang, Vietnam, pp. 41-45.
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© 2017 IEEE. Wearable monitoring systems have been in need for studies of gaits especially freezing of gait detection in patients with Parkinson's disease. The causality of gait freezing is still not fully understood. The histogram of gait freezing is the key assessment of the disease, thus monitoring them in patients' daily life is much appreciated. A real-Time signal processing platform for wearable sensors can help record freezing time instances. However, current monitor systems are calibrated with offline training (patient-dependent) that is cumbersome and time-consuming. In this work, by using acceleration data and spectral analysis, we propose an online/real-Time detection technique. Periods of low acceleration and low spectral coherence are identified and patient-independent parameters are then extracted. Using this set of new features, we validated our method by comparing it with clinicians' labels. The proposed approach achieved an overall mean (±SD) sensitivity (specificity) of 87 ± 0.3% (94±0.3%). To our best knowledge, this is the best performance for automated subject-independent approaches.
Pham, TT, Nguyen, DN, Dutkiewicz, E, McEwan, AL & Leong, PHW 1970, 'Wearable healthcare systems: A single channel accelerometer based anomaly detector for studies of gait freezing in Parkinson's disease', 2017 IEEE International Conference on Communications (ICC), ICC 2017 - 2017 IEEE International Conference on Communications, IEEE, Paris, France.
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© 2017 IEEE. The causality of gait freezing in patients with advanced Parkinson's disease is still not fully understood. Clinicians are interested in investigating the freezing of gait (FoG) histogram of patients in their daily life. To that end, one needs a real-time signal processing platform that can help record freezing information (e.g., timing and the duration of every gait freezing occurrences). Wearable wireless sensors have been proposed to monitor FoG epochs. Existing automated methods using accelerometers have been introduced with high accuracy performance only for subject-dependent settings (e.g., an individual offline training process). This is a troublesome for large scale out-of-lab deployment and time-consuming. In this work, we used spectral coherence analysis for accelerometer data to apply an anomaly detection approach. Conventional features such as energy and freezing index are introduced to help refine normal epochs while the anomaly scores from spectral coherence measures define FoG epochs. Using this new set of features, our new FoG detector for subject-independent settings achieves the mean ±SD sensitivity (specificity) of 89.2±0.3% (95.6 ± 0.3%). To our best knowledge, this is the best performance for automated subject-independent approaches in literature of freezing of gait detection.
Phung, MD, De La Villefromoy, M & Ha, Q 1970, 'Management of solar energy in microgrids using IoT-based dependable control', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. Solar energy generation requires efficient monitoring and management in moving towards technologies for net-zero energy buildings. This paper presents a dependable control system based on the Internet of Things (IoT) to control and manage the energy flow of renewable energy collected by solar panels within a microgrid. Data for optimal control include not only measurements from local sensors but also meteorological information retrieved in real-time from online sources. For system fault tolerance across the whole distributed control system featuring multiple controllers, dependable controllers are developed to control and optimise the tracking performance of photovoltaic arrays to maximally capture solar radiation and maintain system resilience and reliability in real time despite failures of one or more redundant controllers due to a problem with communication, hardware or cybersecurity. Experimental results have been obtained to evaluate the validity of the proposed approach.
Phung, MD, Dinh, TH, Hoang, VT & Ha, Q 1970, 'Automatic Crack Detection in Built Infrastructure Using Unmanned Aerial Vehicles', Proceedings of the International Symposium on Automation and Robotics in Construction (IAARC), 34th International Symposium on Automation and Robotics in Construction, Tribun EU, s.r.o., Brno, Taipei, Taiwan, pp. 823-829.
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This paper addresses the problem of crack detection which is essential for health monitoring of built infrastructure. Our approach includes two stages, data collection using unmanned aerial vehicles (UAVs) and crack detection using histogram analysis. For the data collection, a 3D model of the structure is first created by using laser scanners. Based on the model, geometric properties are extracted to generate way points necessary for navigating the UAV to take images of the structure. Then, our next step is to stick together those obtained images from the overlapped field of view. The resulting image is then clustered by histogram analysis and peak detection. Potential cracks are finally identified by using locally adaptive thresholds. The whole process is automatically carried out so that the inspection time is significantly improved while safety hazards can be minimised. A prototypical system has been developed for evaluation and experimental results are included.
Qi, J & Dah-Chuan Lu, D 1970, 'A flyback converter based partial power processing structure for BESS with voltage/current regulation and battery balancing functionalities', 2017 IEEE International Telecommunications Energy Conference (INTELEC), 2017 IEEE International Telecommunications Energy Conference (INTELEC), IEEE, Broadbeach, QLD, Australia, pp. 381-386.
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This paper presents a flyback converter based partial power processing structure for battery energy storage system (BESS). It combines both of the battery balancing functionality and power stage regulation functionality into one system. The proposed BESS only have one control variable which is the common duty cycle for all the flyback converters. It is used for the voltage or current regulation. There is no active control for the battery balancing because the current sharing of individual battery is directly proportional to the battery terminal voltage in discharging mode and inversely proportional in charging mode. The unbalanced battery terminal voltages will gradually converge while system running. Beyond these, only a small portion of the total discharging/charging power is processed by the converters. The overall system efficiency can be significantly improved compared to traditional BESSs. Experimental results of a prototype with two batteries verified that the proposed BESS provides satisfied performance.
Qin, P-Y, Chen, S-L & Guo, YJ 1970, 'A compound reconfigurable microstrip antenna with agile polarizations and steerable beams', 2017 International Symposium on Antennas and Propagation (ISAP), 2017 International Symposium on Antennas and Propagation (ISAP), IEEE, Phuket, Thailand, pp. 1-2.
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© 2017 IEEE. Achieving both polarization switching and beam steering independently, in a compact antenna structure, is a major challenge for compound reconfigurable antennas. In this paper, a new cavity-backed proximity-coupled reconfigurable microstrip antenna provides an efficient solution. Three different linear polarizations (0°, 45°, 90°) can be obtained by switching PIN diodes on a proximity-coupled feed network. For each polarization state, the main beam can be steered in three directions by using a reconfigurable parasitic-element network. The antenna has nine different working states in total. For all states, the measured input reflection coefficients are below -10 dB, with the measured realized gains ranging from 7.2-8 dBi.
Qin, P-Y, Guo, YJ & Ji, L-Y 1970, 'Reconfigurable partially reflective surface antennas', 2017 Sixth Asia-Pacific Conference on Antennas and Propagation (APCAP), 2017 Sixth Asia-Pacific Conference on Antennas and Propagation (APCAP), IEEE, Xi'an, China, pp. 1-3.
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© 2017 IEEE. In this paper, the research of reconfigurable partially reflective surface (PRS) antennas at University of Technology Sydney (UTS) is introduced. Two reconfigurable PRS antennas are described that can achieve beam scanning and wideband polarization switch, respectively.
Qureshi, JA, Lie, TT, Gunawardane, K, Kularatna, N & Qureshi, WA 1970, 'AC source vs DC source: Charging efficiency in battery storage systems for residential houses', 2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), 2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), IEEE.
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Rafiei, A, Abolhasan, M, Franklin, DR, Safaei, F, Smith, S & Ni, W 1970, 'Cooperative recovery of coverage holes in WSNs via disjoint spanning trees.', ICSPCS, International Conference on Signal Processing and Communication Systems, IEEE, Gold Coast, QLD, Australia, pp. 1-10.
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© 2017 IEEE. Large scale coverage holes (CHs) resulting from correlated node failures, can significantly degrade quality of service and also jeopardise the integrity of WSNs. In the absence of centralised control, the distributed relocation of deployed nodes becomes a promising solution especially in harsh and hostile environments. In this paper, a distributed method is proposed that enables a network to partially or entirely repair itself through a collection of distributed movements of disjoint spanned trees (DS-Trees) towards the CHs. DS-Trees are spanned based on the nodes distances from the CHs, which are autonomously perceived by the nodes and their one-hop neighbours. DS-Trees around the CHs are spanned in a downstream style outwards from the holes, as nodes select their parents based on the minimum distance to the CH from their neighbours; nodes then decide whether or not to follow the movements of their DS-Trees parents. To examine the efficiency of the proposed model, its performance is compared with two Voronoi-based and one force-based node relocation algorithms. Results show that the proposed DS-Tree model either outperforms or matches the alternative approaches across a wide range of scenarios.
Rafiei, A, Abolhasan, M, Franklin, DR, Safaei, F, Smith, S & Ni, W 1970, 'Effect of the number of participating nodes on recovery of WSN coverage holes.', ITNAC, International Telecommunication Networks and Applications Conference, IEEE Computer Society, Melbourne, VIC, Australia, pp. 1-8.
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© 2017 IEEE. Coverage holes (CHs) due to the correlated node failures, if not appropriately addressed in a timely manner, not only disrupt network's operation but also can compromise its integrity. In the absence of centralised control, distributed node relocation can be an effective solution to recover CHs. Relocation algorithms that mainly applied to all nodes to address networks' coverage and unbalanced deployments problems, are not efficient as participating nodes beyond a certain distance and depth from the CHs do not significantly contribute to recovery of CHs. Here, the effects of the number of participating nodes and movement iterations on recovery of CHs are examined in two Voronoi-based and one force-based node relocation algorithms.
Rahman, MA, Islam, MR, Guo, Y, Zhu, J & Lei, G 1970, 'Modified carrier-based over-modulation technique for improved switching performance of multilevel converters', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. A modified over-modulation (OVM) scheme with phase disposed carriers to improve switching performance of cascaded H-bridge multilevel converter is depicted in this article. With the regular OVM techniques, pulse dropping region has higher conduction loss, greater signal distortion and voltage gain. In the proposed OVM method, the switching and conduction loss scenario is improved with lower harmonic distortion. Also, the voltage gain can be increased up to limited range. Four types of reference signals, such as pure sinusoidal signal, sinusoidal 60° bus clamped signal, third harmonic injected signal and third harmonic injected 60° bus clamped signal are used to investigate the overall performance with the proposed OVM method. The OVM technique is applied to a 3.0 kV, 120 kW, 5-level cascaded H-bridge converter and simulated in MATLAB/Simulink environment. The results demonstrate reduced output harmonic distortion, increased voltage gain, lower switching and conduction loss as well as improved efficiency on the whole.
Rahman, ML, Zhang, JA, Huang, X & Quo, YJ 1970, 'Analog antenna array based sensing in perceptive mobile networks', 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Veorna, Italy, pp. 199-202.
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© 2017 IEEE. In this paper, we consider an alternative low-cost and flexible solution of using an analog antenna array for radio sensing at the base station receiver in the recently proposed perceptive mobile networks. We provide receiver beamforming design, and advanced compressive sensing (CS) signal processing techniques for sensing parameter estimation in a multiuser-MIMO (MU-MIMO) communications system. Simulation results are provided and validate the effectiveness of the proposed solution and sensing algorithms.
Rajabi, A, Li, L, Zhang, J & Zhu, J 1970, 'Aggregation of small loads for demand response programs — Implementation and challenges: A review', 2017 IEEE International Conference on Environment and Electrical Engineering and 2017 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), 2017 IEEE International Conference on Environment and Electrical Engineering and 2017 IEEE Industrial and Commercial Power Systems Europe (EEEIC / I&CPS Europe), IEEE, Milan, Italy, pp. 1-6.
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© 2017 IEEE. The concepts of demand response (DR) and demand side management have been in practice by power utilities for many decades. Due to fundamental changes in the electricity structure in recent years, the provision of DR from small loads like residential buildings or electric vehicles has become possible. However, there are still many challenges to the real implementation of DR programs for such customers. Based on a detailed survey of the literature, this paper tries to illustrate the role of aggregators in the implementation and expansion of DR in future smart grids. Then different technical and managerial challenges of DR aggregation for residential customers will be discussed thoroughly.
Rajabi, A, Li, L, Zhang, J, Zhu, J, Ghavidel, S & Ghadi, MJ 1970, 'A review on clustering of residential electricity customers and its applications', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. Clustering is a well-recognized data mining technique which enables the determination of underlying patterns in datasets. In electric power systems, it has been traditionally utilized for different purposes like defining customer load profiles, tariff designs and improving load forecasting. Some surveys summarized different clustering techniques which were traditionally used for customer segmentation and load profiling. The recent changes in power system structure and introduction of new technologies necessitate the new investigation of applications and benefits of clustering methods for power systems. In this regard, this paper aims at reviewing the new research for clustering techniques for residential customers.
Rana, MM, Li, L & Su, SW 1970, 'Distributed State Estimation for Interconnected Synchronous Generators', IFAC-PapersOnLine, IFAC World Congress, Elsevier BV, Toulouse, France, pp. 5418-5423.
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© 2017 In contrast to the traditional centralised power system state estimation methods, this paper investigates the optimal filtering problem for distributed dynamic systems. Specifically, the interconnected synchronous generators are modelled as a state-space linear equation where sensors are deployed to obtain measurements. As the synchronous generator states are unknown, the estimation is required to know the overall operating conditions of large-scale complex power networks. Basically, the proposed algorithm is based on the minimization of the mean squared estimation error, and the optimal gain is computed by exchanging information with their neighboring estimators. Afterwards, the convergence of the developed algorithm is proved so that it can be applied to real-time applications in modern smart grids. Finally, simulation results demonstrate the efficacy of the developed approach.
Rana, MM, Li, L & Su, SW 1970, 'Distributed State Estimation for Microgrids', IFAC-PapersOnLine, the 20th IFAC World Congress, Elsevier BV, Toulouse, France, pp. 10202-10207.
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© 2017 This paper proposes a novel distributed consensus filter based dynamic state estimation algorithm with its convergence analysis for modern power systems. The novelty of the scheme is that the algorithm is designed based on the mean squared error and semidefinite programming approaches. Specifically, the optimal local gain is computed after minimizing the mean squared error between the true and estimated states. The consensus gain is determined by a convex optimization process with a given sub-optimal local gain. Furthermore, the convergence of the proposed schemed is analysed after stacking all the estimation error dynamics. The Laplacian operator is used to represent the interconnected filter structure as a compact error dynamic for deriving the convergence condition of the algorithm. The developed approach is verified by using the mathematical dynamic model of the renewable microgrid. It shows that the proposed distributed scheme is effective to properly estimate the system states.
Reza, CMFS, Lu, DD-C & Qin, L 1970, 'Single-inductor multiple-source mixer for DC power packet dispatching system', 2017 IEEE Second International Conference on DC Microgrids (ICDCM), 2017 IEEE Second International Conference on DC Microgrids (ICDCM), IEEE, Nuremburg, Germany, pp. 553-557.
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© 2017 IEEE. DC power packet dispatching system is reported recently aiming to deliver power in a packet form. It can utilize less power conversion stages which increases power distribution efficiency and monitor load demand intelligently from source side to keep the system stable. A multiple-energy-source mixer based on a multiple-input single-inductor buck converter for DC power packet dispatching system is proposed. It is capable of generating power packets at different voltage levels by time sharing of multiple power sources. In this work, three different sources including a PV panel and two DC voltage sources are used for the power packet dispatching system. A control strategy is devised in order that the PV panel can track maximum power point (MPP) approximately and the PV is given a priority to share power in each power packet generation. Experimental results are reported to verify the proposed mixer and its control strategy for DC power packet dispatching system.
Riaz, MH, Rashid, U, Ali, M & Li, L 1970, 'Internet of Things Based Wireless Patient Body Area Monitoring Network', 2017 IEEE International Conference on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData), 2017 IEEE International Conference on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData), IEEE, Exeter, England, UK, pp. 970-973.
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© 2017 IEEE. Wireless body area network is a climbing innovation in machine world and assumes an exceptionally lively part in general public. By using this technology, medical specialists can check complete subtle elements of a patient from a remote area and can prescribe a suitable solution. The primary motivation behind this innovation is to decrease the work load at doctor's facilities and give proficient medical services. For this purpose, different body sensors are used to monitor the physical parameters such as electro-cardiogram, heart rate, blood pressure and body temperature of patients, and use wireless sensor network (WSN) in conjunction with internet of things (IoT) to continuously monitor the patient condition. Health parameters data is also sent to the medical personnel with the help of wireless technology module such as a Zigbee (S2 module) and internet cloud computing. The proposed system is not only economically viable but also offers enough portability to be used in remote under-privileged areas for better health facilities.
Roselin, AG, Nanda, P & Nepal, S 1970, 'Lightweight Authentication Protocol (LAUP) for 6LoWPAN Wireless Sensor Networks', 2017 IEEE Trustcom/BigDataSE/ICESS, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, Sydney, pp. 371-378.
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© 2017 IEEE. 6LoWPAN networks involving wireless sensors consist of resource starving miniature sensor nodes. Since secured authentication of these resource-constrained sensors is one of the important considerations during communication, use of asymmetric key distribution scheme may not be the perfect choice to achieve secure authentication. Recent research shows that Lucky Thirteen attack has compromised Datagram Transport Layer Security (DTLS) with Cipher Block Chaining (CBC) mode for key establishment. Even though EAKES6Lo and S3K techniques for key establishment follow the symmetric key establishment method, they strongly rely on a remote server and trust anchor for secure key distribution. Our proposed Lightweight Authentication Protocol (LAUP) used a symmetric key method with no preshared keys and comprised of four flights to establish authentication and session key distribution between sensors and Edge Router in a 6LoWPAN environment. Each flight uses freshly derived keys from existing information such as PAN ID (Personal Area Network IDentification) and device identities. We formally verified our scheme using the Scyther security protocol verification tool for authentication properties such as Aliveness, Secrecy, Non-Injective Agreement and Non-Injective Synchronization. We simulated and evaluated the proposed LAUP protocol using COOJA simulator with ContikiOS and achieved less computational time and low power consumption compared to existing authentication protocols such as the EAKES6Lo and SAKES.
Royel, S & Ha, Q 1970, 'Frequency shaped sliding mode control of magnetorheological smart structure systems', 2017 IEEE International Conference on Mechatronics (ICM), 2017 IEEE International Conference on Mechatronics (ICM), IEEE, Churchill, VIC, Australia, pp. 117-122.
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This paper addresses the problem of controlling
multi-degree-of-freedom (MDoF) smart structures integrated
with magnetorheological (MR) devices that are subject to non-
linearity and hysteresis. A fluid based device, namely the MR
damper (MRD), is considered in this study, where hysteresis
appears in both force-displacement and force-velocity relation-
ships of the smart device. Such nonlinear dynamics limit the
performance of the device when embedded in smart structures.
The describing function (DF) technique is employed using only
the displacement as input to the nonlinearity to characterize
this multivalued mechanism. By incorporating the proposed
model into the system dynamics, frequency shaped sliding mode
control (FSSMC) is developed to achieve structural resilience
and sustainability against nonlinearities, modeling uncertainties,
and disturbances from dynamic loadings. Frequency response
functions (FRFs) are obtained for possible analysis of system
conditional assessment in the frequency domain. Simulations
are reported for a three-story building model integrated with
two identical current-dependent MR dampers subject to one-
dimensional quake-induced vibration to investigate lateral dy-
namic responses, as produced by earthquakes or strong winds.
Saadat, A, Ni, W & Vesilo, R 1970, 'Spectrum sharing in femtocell based networks using an equal priority power control game', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, QLD, Australia, pp. 1-6.
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© 2017 IEEE. In order to keep pace with the recent proliferation of wireless services and mobile applications, efficient and flexible radio spectrum utilization needs to be ensured in next-generation mobile networks. In this regard, we present a game-Theoretic spectrum-sharing scheme, by considering coexistence of a set of femtocells, belonging to multiple networks, in a coverage area where all cells have an equal priority of accessing the spectrum. We formulate a non-cooperative transmit-power-control game, in which all the femtocells share the spectrum by adjusting their transmit powers according to the interference, until the transmit power is stabilized. We prove that a Nash equilibrium exists for the proposed non-cooperative game, verify that it is unique and highlight the role of specific game parameters in this regard. A novel dual-mode solution is proposed for implementation of the game, which ensures that an equilibrium point can be reached having minimum coordination among the network elements. Finally, we present simulation results to show that the game converges to a Nash equilibrium and provide a throughput performance analysis.
Sadra, S & Abolhasan, M 1970, 'On improving the saturation performance of IEEE802.15.6-based MAC protocols in Wireless Body Area Networks', 2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC), 2017 13th International Wireless Communications and Mobile Computing Conference (IWCMC), IEEE, Valencia, Spain, pp. 1233-1238.
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© 2017 IEEE. Wireless Body Area Networks (WBANs) were designed to collect and transfer vital physiological parameters within a short distance of the human body by employing low-power, light-weight, small-sized and smart implantable or wearable sensor devices. Lately, WBANs are expected to support various types of applications with data rates from a few Kbps upto 10 Mbps and satisfy the heterogeneous requirements of both medical and consumer electronics applications. Hence, novel communication protocols that consider a unique set of constraints and demands of these networks need to be developed to provide optimum system efficiency and data transmission reliability. As the IEEE 802.15.6 Medium Access Control (MAC) protocol based on the latest WBANs standard, cannot maintain the balance between the strict energy limitation and Quality of Service (QoS) requirements of such networks, this paper focuses on developing MAC protocols to improve the performance of WBANs specifically in the saturation condition. Two IEEE802.15.6-based MAC protocols are proposed to enhance channel access for the highest user priority and the other user priorities in saturated networks. The simulation results show better network performance as well as lower energy consumption in the proposed MAC protocols compared to the IEEE 802.15.6 MAC protocol.
Salah, A, Guo, Y & Dorrell, D 1970, 'Monitoring and damping unbalanced magnetic pull due to eccentricity fault in induction machines: A review', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. Condition monitoring can diagnose the inception of fault mechanisms in induction motors, thus avoiding failure and expensive repairs. Therefore, there is a strong need to develop an efficient condition monitoring. The main target is to achieve a relatively low cost and/or non-invasive system which is still powerful in terms of monitoring for online detection of developing faults. The presented paper addresses rotor eccentricity faults and studies conventional monitoring techniques for induction motors. In order to reduce the unbalanced magnetic pull (UMP) in case of an eccentric rotor, the eccentricity-generated additional airgap flux waves should be reduced. The radial forces in an induction motor are calculated, and the characteristics of unbalanced magnetic pull are described.
Schell, AW, Takashima, H, Tran, TT, Aharonovich, I & Takeuchi, S 1970, 'Spectroscopy of Single Quantum Emitters in Hexagonal Boron Nitride Using Linear and Non-Linear Excitation', Conference on Lasers and Electro-Optics, CLEO: QELS_Fundamental Science, OSA, San Jose, CA, USA, pp. 1-2.
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© 2017 IEEE. Excitation of single photon emitters via a two-photon process can be employed for high resolution imaging and has applications in quantum optics. Here, we present one- and two-photon excitation of single defects in hexagonal boron.
Setiadi, H, Mithulananthan, N & Hossain, MJ 1970, 'Impact of battery energy storage systems on electromechanical oscillations in power systems', 2017 IEEE Power & Energy Society General Meeting, 2017 IEEE Power & Energy Society General Meeting (PESGM), IEEE, pp. 1-5.
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© 2017 IEEE. Due to high penetrations of renewable energy systems (RESs), deployment of energy storage is significantly increased in recent years. Among varieties of energy storage options, battery energy storage systems (BESSs) are getting popular as they provide reliable performance with low-inertia RESs. Although BESS smooth out RES energy, they can negatively influence low-frequency oscillations of power systems due to inertia-less characteristics. However, a very scant attention has been paid to understand the BESS impact on low frequency oscillation of power systems. Hence, this paper investigates the impact of BESSs on the low-frequency oscillation. In order to analyse the impact of BESS's control and its dynamic interaction, a single machine infinite bus, popularly known as 'Philip-Heffron model' is used. Eigenvalue, nonlinear time domain simulation and participation factor analyses are used to examine system's behaviours with BESS. From simulation results, it is found that the gain of BESS's controller changes the dynamic behaviour of synchronous machines and optimally tuned gain can enhance system's damping.
Shahzad, K, Guo, Y, Li, L & Dorrell, D 1970, 'Design of high speed permanent magnet generator for solar co-generation system using motor-CAD', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney.
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© 2017 IEEE. High speed brushless permanent-magnet generators (HSBPMGs) may be the most suitable choice for small solar co-generation systems due to a variety of merits. For instance, they offer substantial reduction in size, and thermally excellent high-power density, which reduces the running costs with good performance and reliability. Moreover, high efficiencies i.e. over 90%, light-weight, low operating temperature, high insulation, no brushes/slip rings and almost negligible cogging torque make HSBPMGs ideal for co-generation systems. However, because of the very high rotor speed and high stator frequency, the design of HSBPMG is quite different from designing a conventional generator with low speed and low frequency. As the speed increases, the losses and temperature go up, and thus careful attention is needed while selecting the design parameters and material for the machine. This paper is aimed to use the basic design process for HSBPMGs running at 60,000rpm, with 6.6kW capacity keeping the losses minimum by using an appropriate material and cooling method. Finite element analysis of the machine is carried by using Motor-CAD simulation software, and modeling of a prototype machine is presented.
Shen, L, Dah-Chuan Lu, D & Fu, J 1970, 'Sliding mode control of a bidirectional grid connected three phase two-stage PV system with space vector PWM', 2017 36th Chinese Control Conference (CCC), 2017 36th Chinese Control Conference (CCC), IEEE, Dalian, China, pp. 3553-3558.
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© 2017 Technical Committee on Control Theory, CAA. A bidirectional grid connected three phase two-stage PV system with DC loads is studied in this paper. The dq frame model is derived in detail, which simplifies the analysis and the controller design. With the dq frame state space model, the switching signals are also converted to the dq frame, which decouples the control input under the dq frame. An adaptive law is designed to estimate the unknown reference value of direct-axis current. The three phase converter can work bidirectionally according to the signal of the direct-axis current. Then the power balance between the PV generation and grid can be realized dynamically. Simulation results show the effectiveness of the proposed control scheme.
Shen, Y, Sun, X, Chen, L, Yang, Z, Li, K, Zhu, J & Guo, Y 1970, 'Comparison of torque characteristics for a novel segmented and a conventional switched reluctance motors', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. The extensive applications of switched reluctance motor (SRM) have been limited due to its drawback of torque ripple. Thus, the reduction of torque ripple is an important problem in studying the SRM. A novel 16/10 segmented SRM (SSRM) is proposed in this paper. The proposed SSRM performs well in terms of torque ripple and tolerant-fault characteristic. The stator of the proposed structure is constructed from exciting and auxiliary stator poles, while the rotor consists of a series of discrete segments. Moreover, the torque ripple is evaluated by comparing with the conventional 8/6 SRM. Finally, the tolerant-fault characteristic of the proposed SSRM and conventional SRM are compared as well. The finite element method (FEM) is employed to demonstrate the prominent advantages of static and dynamic characteristics of the proposed SSRM.
Sheng, Z, Tuan, HD, Nasir, AA & Poor, HV 1970, 'Secrecy Throughput of Wireless Interference Networks with Uncertain Channel State Information', 2017 IEEE Globecom Workshops (GC Wkshps), 2017 IEEE Globecom Workshops (GC Wkshps), IEEE, Singapore, Singapore, pp. 1-7.
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© 2017 IEEE. Considering a multi-user interference network with an eavesdropper, this paper investigates the problem of power allocation to optimize the worst secrecy throughput among the network links. Three scenarios for the access of channel state information are considered: perfect channel state information, partial channel state information with channels from the transmitters to the eavesdropper exponentially distributed, and imperfectly known channels between the transmitters and the users with exponentially distributed errors. The paper develops various path-following procedures of low complexity and rapid convergence for the optimal power allocation. Their effectiveness and viability are illustrated through numerical examples. The power allocation schemes are shown to achieve high secrecy throughput.
Shi, X, Zhu, J, Dah-Chuan Lu, D & Li, L 1970, 'A multi-functional modular approach to developing microgrid systems', 19th International Conference on Electrical Machines and Systems, ICEMS 2016, International Conference on Electrical Machines and Systems, IEEE, Chiba, Japan, pp. 1-5.
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Due to the impact of intermittency of renewable energy sources on electricity distribution networks, using energy storage systems (ESS) to stablize the grid are essential. Thus an intelligent system to actively control the distributed generations (DG), ESS and load are of vital significance for better integration of DGs to utility grid. This paper proposes a novel topology of microgrid system with modular design and wireless communication ability. Compared with the conventional microgrid system, it has fully modular design with the advantage of convenient manufacturing process, transport, installation, maintenance, capacity expansion, and upgrade. The specific hierarchical control and wireless communication can make the microgrid system smart in the power grid.
Shi, X, Zhu, J, Dah-Chuan Lu, D & Li, L 1970, 'Advanced multi-functional model predictive control for three-phase AC/DC converters', 19th International Conference on Electrical Machines and Systems, ICEMS 2016, International Conference on Electrical Machines and Systems, IEEE, Chiba, Japan.
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With the conventional model predictive control (MPC) based direct power control of three-phase AC/DC converters, the active and reactive powers can be simultaneously controlled by a single cost function. A change in parameters of either the active or reactive power within the cost function will affect the other, leading to poor dynamic performance of transient response. Besides, the steady state performance of the conventional MPC is affected by one-step-delay of digital implementation. This paper proposes an advanced multi-functional MPC of three-phase full-bridge AC/DC converter for high power applications. It has multiple functions such as one-step-delay compensation, power ripple reduction, switching frequency reduction, and dynamic mutual influence elimination. Using the proposed modified cost function, both the steady state and dynamic performances of the converter can be improved. Finally, the simulation results are reported to validate the advancement of the proposed control strategy in comparison with other control methods.
Shi, Y, Tuan, HD & V. Savkin, A 1970, 'Three-phase Optimal Power Flow for Smart Grids by Iterative Nonsmooth Optimization', Proceedings of the 6th International Conference on Smart Cities and Green ICT Systems, 6th International Conference on Smart Cities and Green ICT Systems, SCITEPRESS - Science and Technology Publications, Porto, Portugal, pp. 323-328.
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© 2017 by SCITEPRESS Science and Technology Publications, Lda. All Rights Reserved. Optimal power flow is important for operation and planning of smart grids. The paper considers the so called unbalanced thee-phase optimal power flow problem (TOPF) for smart grids, which involves multiple quadratic equality and indefinite quadratic inequality constraints to model the bus interconnections, hardware capacity and balance between power demand and supply. The existing Newton search based or interior point algorithms are often trapped by a local optimum while semidefinite programming relaxation (SDR) even fails to locate a feasible point. Following our previously developed nonsmooth optimization approach, computational solution for TOPF is provided. Namely, an iterative procedure for generating a sequence of improved points that converges to an optimal solution, is developed. Simulations for TOPF in unbalanced distributed networks are provided to demonstrate the practicability and efficiency of our approach.
Shi, Z, Sun, X, Chen, L, Yang, Z, Li, K, Zhu, J & Guo, Y 1970, 'Parameter matching and structure optimal design of a brushless DC motor for a battery electric vehicle', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. Calculation and matching of the main parameters of a brushless DC (BLDC) motor for a Battery electric vehicle (EV) is studied in this paper. Usually, different shapes of permanent magnet (PM) and different magnetizing methods will affect the performance of the motor. Especially when the motor is designed for an EV, more elements need to be considered, such as efficiency under normal operating conditions and torque ripple. So in this paper the performance of PMs with different shapes and different magnetizing methods will be compared by finite element analysis (FEA). Finally, the structure of the stator and rotor will also be optimized to obtain the required prototype model.
Siahpoosh, MK, Dorrell, D & Li, L 1970, 'Ferroresonance assessment in a case study wind farm with 8 units of 2 MVA DFIG wind turbines', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. This paper studies the transient and sustained ferroresonance phenomenon in wind farms connected to a power distribution system. Ferroresonance can be critical for wind turbines during switching or fault conditions. This results in effects such as harmonics, voltage dips and overvoltage in the system [1]. The ferroresonance current is able to damage the machine and the rotor side converter, and as a consequence, the system must be protected [2]. In this paper, first the existence of ferroresonance in wind farms has been assessed. Software modeling and a validation method has been proposed and the simulation results for different system arrangements have been presented. In general, engineers can often work around nonlinearities using a simplified linear approximation to calculate or predict performance within the 'normal' range of operation. This is not possible in the case of ferroresonance since linearized calculations will not predict it [3][4]. Therefore PSCAD-EMTDC software is used in this study to analyse the behaviour of a wind farm with Doubly Fed Induction Generators (DFIGs) [5][6]. Results show that ferroresonance is a function of network components; specifically, the lengths of cables, types of wind turbine generators, power transformers and transmission lines.
Siahpoosh, MK, Li, L & Dorrell, DG 1970, 'Wind farm grounding system analysis', 2017 IEEE Energy Conversion Congress and Exposition (ECCE), 2017 IEEE Energy Conversion Congress and Exposition (ECCE), IEEE, Cincinnati, OH, USA, pp. 4780-4785.
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© 2017 IEEE. this paper studies a real-case grounding system design for a wind farm and associated equipment. The design is based on the safety criteria provided by Australian and International guidelines listed in the references [1-5]. The wind farm grounding system consists of wind turbine generators, tower base padmounts, 33 kV cable screen and a primary substation. In this paper, grounding system and ground potential rise analyses are presented and discussed. In this study, the conventional earthing system of a wind farm is assessed. The impacts of turbines foundation reinforcement, tower base substation, inter-connection cables and mutual coupling between neighboring turbines grounding systems were simulated. Several methods of improvement are accordingly proposed. Since it is more likely to have farm animals in the vicinity of a wind turbine during the phase to ground fault, a new method for calculation of safe step voltage for farm animals is also proposed.
Simorangkir, RBVB, Yang, Y & Esselle, K 1970, 'Active and Passive Antennas Based on Unconventional Materials, for Next Generation Wearable Wireless Devices (Invited Paper)', 2017 IEEE MTT-S International Microwave Symposium, Honolulu, Hawaii.
Simorangkir, RBVB, Yang, Y & Esselle, KP 1970, 'Performance of embroidered higher-order mode antennas with different stitching patterns', 2017 11th European Conference on Antennas and Propagation (EUCAP), 2017 11th European Conference on Antennas and Propagation (EUCAP), IEEE, Paris, France, pp. 177-180.
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© 2017 Euraap. In this paper the performance of TM21 resonance-mode circular patch antennas embroidered with different stitching patterns is discussed and compared. The goal is to investigate the difference in the performance when the antenna is embroidered with stitches following the antenna current paths as opposed to some simple patterns such as horizontal and vertical ones. This creates an alternative solution for embroidering prototypes of wearable antennas with complicated current distributions. The results reveal that by embroidering the antenna in line with the complex TM21 current distribution a good monopole-like radiation pattern is achieved, which is close to an etched copper prototype's used as the reference. However, with a dense horizontal stitching pattern an acceptable monopole-like radiation pattern can also be achieved with quite good gain and efficiency. While simplifying the embroidery process, the use of the simple horizontal pattern with high density suffers from high cross-polarization and thread consumption as compromises.
Simorangkir, RBVB, Yang, Y, Esselle, KP & Diao, Y 1970, 'A varactor-tuned frequency-reconfigurable fabric antenna embedded in polymer: Assessment of suitability for wearable applications', 2017 IEEE MTT-S International Microwave Symposium (IMS), 2017 IEEE/MTT-S International Microwave Symposium - IMS 2017, IEEE, Honolulu, Hawaii, pp. 204-207.
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© 2017 IEEE. In this paper, we present a novel class of wearable antennas that are flexible, electronically tunable, and robust. They consist of conductive fabric parts, used as the radiator, with polydimethylsiloxane (PDMS) polymer utilized to form the substrate as well as the full encapsulation of the radiator including its electronic tuning elements. To validate the concept, a prototype that provides frequency tuning from 2.3 to 2.65 GHz has been fabricated and tested. The fabrication process is detailed and experimental investigations on its suitability for wearable applications are presented. To assess the antenna robustness, its reconfigurability under severe physical deformations has been studied through washing the antenna and also by wrapping it on the head and wrist of a UWB human muscle equivalent phantom. The antenna's effect on body has also been investigated through Specific Absorption Rate (SAR) measurement. The results confirm that the antenna is a promising candidate for modern wearable devices.
Sinha, S & Chaczko, Z 1970, 'Concepts and Observations in Artificial Endocrine Systems for IoT Infrastructure', 2017 25th International Conference on Systems Engineering (ICSEng), 2017 25th International Conference on Systems Engineering (ICSEng), IEEE, Las Vegas, NV, USA, pp. 427-430.
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© 2017 IEEE. Artificial Endocrine Systems is the study of nature’s highly evolved and advanced resource management system that sustains life. The basic units of the endocrine system are the chemical messengers, otherwise known as hormones, which in enough numbers produce cascading effects in the host organism that promotes growth, maintains metabolism and much more. This behaviour is in effect a living metaphor indicative of the high throughput, constant flux and stochastic interactions that exist in complex topologies such as large scale IoT infrastructures.
Siwakoti, YP & Blaabjerg, F 1970, 'H-Bridge transformerless inverter with common ground for single-phase solar-photovoltaic system', 2017 IEEE Applied Power Electronics Conference and Exposition (APEC), 2017 IEEE Applied Power Electronics Conference and Exposition (APEC), IEEE, Tampa, FL, pp. 2610-2614.
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Siwakoti, YP, Soltani, M, Blaabjerg, F & Mostaan, A 1970, 'A novel quasi-SEPIC high-voltage boost DC-DC converter', 2017 IEEE Applied Power Electronics Conference and Exposition (APEC), 2017 IEEE Applied Power Electronics Conference and Exposition (APEC), IEEE, Tampa, FL, USA, pp. 2213-2216.
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© 2017 IEEE. This paper proposes a modified coupled-inductor SEPIC dc-dc converter for low power and high voltage gain applications such as for piezoelectric drive systems. The converter uses the same components as of SEPIC converter with an additional diode. Compared to conventional topologies with similar voltage gain expression, the proposed topology uses less components to achieve same or even higher voltage gain. This helps to design a very compact and light weight converter with higher power density at lower cost. Due to brevity, the principle of operation, theoretical analysis and comparison supported by some key experimental results of 5 W prototype are presented in brief.
Song, H, Wu, Q & Dong, H 1970, 'EMI-based Diagnosis to Grounding Grids by Combining Ensemble Empirical Mode Decomposition and ICA', Proceedings of the 8th International Conference on Computer Modeling and Simulation, ICCMS '17: 8th International Conference on Computer Modeling and Simulation, ACM, Canberra, Australia, pp. 196-200.
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© 2017 ACM. Grounding grids have been performed an essential role in electric transformer substations. The nondestructive diagnosis system applies transforms the condition of the undergrounding conductors to the surficial induced electric signal in sensing coil. However, the induced signal cannot be used directly to diagnosis due to the raw measurement is a mixture of responses from signal of interest, strong interference and other unknown noises. Therefore the separation of individual signatures from the mixture is posed as a blind source separation (BSS) problem. To extract the induced signal corrupted by noise, the independent component analysis (ICA) method is considered. By combining the EEMD and FastICA, the single-channel signal is decomposed into its ICs. The desired signal is then reconstructed to visualize the break point of the grounding grid. The results show this approach can be used to effectively diagnosis grounding gird in harsh electromagnetic environment.
Soon, JL, Lu, DD-C, Ling Qin & Sathiakumar, S 1970, 'Development of multi-mode step down DC/DC converters with fault-tolerant capability', 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia (IFEEC 2017 - ECCE Asia), 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia (IFEEC 2017 - ECCE Asia), IEEE, Kaohsiung, Taiwan, pp. 127-133.
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© 2017 IEEE. This paper proposes a three-switch step-down DC/DC converter with fault-tolerant capabilities. Detection of faults during power converter switching operations is important to avoid failures. In this paper, fault analysis is based on open circuit fault detection (OCFD) techniques. A numerical solution is developed based on the joule-integral principle to design OCFD hardware protection. Under normal operating conditions, either one of the three switching modes, namely, buck, buck-boost, or flyback, is allowed. The two other switches remain in standby mode. All switches share the same output filter component to achieve a single-switch converter operation in any mode. A microcontroller is used to monitor open circuit faults, and identify MOSFET failure and normal operating conditions. If an open circuit fault occurs on the main switch, the other switch will be activated to provide an alternate current path to maintain output regulation. Simulated and experimental results are demonstrated to verify the design and its fault-tolerant operations.
Stephenson, RM, Naik, GR & Chai, R 1970, 'A system for accelerometer-based gesture classification using artificial neural networks', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Jeju island, Korea, pp. 4187-4190.
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A great many people suffer from neurological movement disorders that render typical hardware interface devices ineffective. A need exists for a universal interface device that can be trained to accept a wide range of inputs across varying types and severities of movement disorders. In this regard, this paper details the design, testing and optimization of an accelerometer-based gesture identification system. A Bluetooth-enabled IMU mounted on the wrist provides hand motion trajectory information to a local terminal. Several techniques are applied to decrease the intra-class variance and reduce classifier complexity including filtering, segmentation and temporal scaling. Datasets consisted of 520 training samples, 260 validation samples and a further 520 testing samples. A multi-layer feed forward artificial neural network (ML-FFNN) was used to classify the input space into 26 different classes. Initial system accuracy, using arbitrary hyperparameters was 77.69% with final optimized accuracy at 99.42%.
Suankaewmanee, K, Hoang, DT, Niyato, D, Sawadsitang, S, Wang, P & Han, Z 1970, 'Performance Analysis and Application of Mobile Blockchain', 2018 International Conference on Computing, Networking and Communications, ICNC 2018, International Conference on Computing, Networking and Communications, IEEE, Maui, HI, USA, pp. 642-646.
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Mobile security has become more and more important due to the boom of mobilecommerce (m-commerce). However, the development of m-commerce is facing manychallenges regarding data security problems. Recently, blockchain has beenintroduced as an effective security solution deployed successfully in manyapplications in practice, such as, Bitcoin, cloud computing, andInternet-of-Things. However, the blockchain technology has not been adopted andimplemented widely in m-commerce because its mining processes usually requireto be performed on standard computing units, e.g., computers. Therefore, inthis paper, we introduce a new m-commerce application using blockchaintechnology, namely, MobiChain, to secure transactions in the m-commerce.Especially, in the MobiChain application, the mining processes can be executedefficiently on mobile devices using our proposed Android core module. Throughreal experiments, we evaluate the performance of the proposed model and showthat blockchain will be an efficient security solution for future m-commerce.
Suarez-Rodriguez, C, Jayawickrama, BA, He, Y, Bader, F & Heimlich, M 1970, 'Performance analysis of REM-based handover algorithm for multi-tier cellular networks.', PIMRC, Annual International Symposium on Personal, Indoor, and Mobile Radio Communications, IEEE, Montreal, QC, Canada, pp. 1-6.
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© 2017 IEEE. The advent of 5G networks, where a plethora of spectrum-sharing schemes are expected to be adopted as an answer to the ever-growing users' need for data traffic, will require addressing mobility ubiquitously. The trend initiated with the deployment of heterogeneous networks and past standards will give way to a multi-tiered network where different services will coexist, such as device-to-device, vehicle-to-vehicle or massive-machine communications. Because of the high variability in the cell sizes given the different transmit powers, the classical handover process, which relies solely on measurements, will lead to an unbearable network overhead as a consequence of the high number of handovers. The use of spatial databases, also known as radio environment maps (REM), was first introduced as a tool to detect opportunistic spectrum access opportunities in cognitive radio applications. Since then, REM usage has been widely expanded to cover deployment optimization, interference management or resource allocation to name a few. In this paper, we introduce a handover algorithm that can predict the best network connection for the current user's trajectory from a radio environment map. We consider a geometric approach to derive the handover and handover-failure regions and compare the current handover algorithm used in Long-Term Evolution with our proposed one. Results show a drastic reduction in the number of handovers while maintaining a trade-off between the ping-pong handover and the handover-failure probabilities.
Subasinghage, K, Gunawardane, K, Lie, TT & Kularatna, N 1970, 'Single-input, dual polarity, dual output DC-DC converter implementation based on the SCALDO technique', 2017 IEEE International Conference on Industrial Technology (ICIT), 2017 IEEE International Conference on Industrial Technology (ICIT), IEEE.
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Sun, H, Ding, C, Guo, YJ & Mittra, R 1970, 'A wideband dipole antenna based on a non-uniformly segmented structure', 2017 11th European Conference on Antennas and Propagation (EUCAP), 2017 11th European Conference on Antennas and Propagation (EUCAP), IEEE, Paris, France, pp. 3572-3574.
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© 2017 Euraap. The design of a wideband, vertically polarized omnidirectional dipole antenna based on a non-uniformly segmented structure is presented. The proposed non-uniformly segmented configuration mitigates the phase change of the currents flowing in the long dipole arms, so that the reverse currents which deteriorate the radiation pattern can be avoided, and a stable omnidirectional pattern can be maintained over a wide frequency band. Simulation results show that the proposed dipole has a wide pattern bandwidth of 66%, ranging from 1.96 GHz to 3.90 GHz, with S11 less than -10 dB. Within the band, the main lobe of the dipole remains in the broadside direction in the E-plane and the antenna achieves the desirable omnidirectional radiation pattern, with a gain flatness of less than 0.3 dB in the H-plane.
Sun, Y, Bautista, MG, Zhu, F & Dutkiewicz, E 1970, 'Design of an Elliptic Filter Using Multiple-Loop Feedback Structure in CMOS Technology for Analogue Signal Processing', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, NSW, Australia, pp. 1-5.
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© 2017 IEEE. Design of high-performance continuous- time filter (CTF) for analogue signal processing is presented in this paper. To demonstrate of using a novel voltage-mode multiple-loop feedback (MLF) approach for CTF design, a 5th-order elliptic lowpass filter (LPF) is implemented in a standard 0.18-μm CMOS technology. The LPF is based on an inverse-follow-the-leader feedback structure with an input distribution network to generate the required transmission zeros. The LPF consumes 35 mA from a single 1.8 V power supply and it has a cut-off frequency of 30 MHz with less than 0.7 dB passband ripple and more than 60 dB stopband attenuation. In addition, a 65 dB dynamic range is achieved.
Sung, CK, Li, S, Hedley, M, Nikolic, N & Ni, W 1970, 'Skew log-normal channel model for indoor cooperative localization', 2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), IEEE, Montreal, QC, Canada, pp. 1-5.
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© 2017 IEEE. The performance of cooperative localization using received signal strength (RSS) benefits from accurate radio channel modeling. While log-normal shadowing is commonly used to model the relationship between RSS and range, the RSS error distribution in indoor environments has been observed to be neither normal nor symmetric. In this paper, we propose a skew log-normal channel model, which includes the standard log-normal model as a special case. We further propose an algorithm for using this model for RSS based cooperative localization. The algorithm was evaluated using data from an electro-magnetic simulation of an aircraft cabin, and was shown to generate more accurate node locations compared to the use of log-normal shadowing in the same localization algorithm.
Takalkar, MA & Xu, M 1970, 'Image Based Facial Micro-Expression Recognition Using Deep Learning on Small Datasets', 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), IEEE, Sydney, Australia, pp. 1-7.
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© 2017 IEEE. Facial micro-expression refers to split-second muscle changes in the face, indicating that a person is either consciously or unconsciously suppressing their true emotions and even mental health. Therefore, micro-expression recognition attracts increasing research efforts in both fields of psychology and computer vision. Existing research on micro-expression recognition has mainly used hand-crafted features, for example, Local Binary Pattern-Three Orthogonal Planes (LBP-TOP), Gabor filter and optical flow. Recently, Deep Convolutional neural systems have demonstrated a high degree effectiveness for difficult face recognition tasks. This paper explores the possible use of deep learning for micro-expression recognition. To develop a reliable deep neural network extensive training sets are required with a huge number of labeled image samples. However, micro-expression recognition is a challenging task due to the repressed facial appearance and short duration, which results in the lack of training data. In this paper, we propose to generate extensive training datasets of synthetic images using data augmentation on CASME and CASME II databases. Then, these datasets are combined to tune a satisfactory CNN-based micro-expression recognizer. Experimental results demonstrate the effectiveness of the proposed CNN approach in image based micro- expression recognition and present comparable results with the best-related works.
Tam, HHM, Tuan, HD, Nasir, AA & Duong, TQ 1970, 'Power splitting for MIMO energy harvesting in multi-user networks', 2017 International Conference on Recent Advances in Signal Processing, Telecommunications & Computing (SigTelCom), 2017 International Conference on Recent Advances in Signal Processing, Telecommunications & Computing (SigTelCom), IEEE, Da Nang, Vietnam, pp. 217-222.
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© 2017 IEEE. We consider a multicell multi-user multiple-input-multiple-output (MU-MIMO) network and propose the efficient design of precoding matrices for the sum throughput maximization under throughput QoS constraints and energy harvesting (EH) constraints for energy-constrained devices in both downlink (DL) and uplink (UL) transmissions. We employ power splitting (PS) approach at the receiver to ensure practical EH and information decoding (ID). The considered practical problem is quite complex due to highly non-convex objective and constraints. Towards this end, we develop a new path-following algorithm for its solution, which just requires a convex quadratic program at each iteration and promises quick convergence.
Tan, Z, Jamdagni, A & Liu, RP 1970, 'Message from the SECSOC 2017 Workshop Chairs', 2017 IEEE Trustcom/BigDataSE/ICESS, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, p. xxxi.
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Tavakoli, A, Najafi, A, Haque, ME, Hossain, MJ & Negnevitsky, M 1970, 'Voltage regulation for off-peak and peak conditions in distribution networks with the high penetration of PV units', 2017 Australasian Universities Power Engineering Conference (AUPEC), 2017 Australasian Universities Power Engineering Conference (AUPEC), IEEE.
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Teng, Q, Cui, H, Duan, J, Zhu, J, Guo, Y & Lei, G 1970, 'Extended state observer-based vector control for PMSM drive system with single phase current sensor', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. A novel extended state observer (ESO)-based vector control (VC) strategy is developed for permanent magnet synchronous motor (PMSM) drive systems with only one phase current sensor. Generally, to achieve high precision control, two phase current sensors are indispensable for successful operation of the feedback control. In response to a phase current sensor fault, by use of technique of ESO, a new observer for estimating both the remaining two phase currents and time-varying stator resistance is put forward. To improve the performance and decrease system high frequency vibration, a nonlinear exponential function is used to replace the switch function in conventional ESO. The resultant ESO-based VC strategy for PMSM drive system with single phase current sensor has strong robustness and satisfactory control performance. Numerical simulation validates the feasibility and effectiveness of the proposed scheme.
Teng, Q, Tian, J, Duan, J, Cui, H, Zhu, J & Guo, Y 1970, 'Sliding-mode MRA observer-based model predictive current control for PMSM drive system with DC-link voltage sensorless', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. A sliding-mode model reference adaptive (MRA) observer-based model predictive current control (MPCC) strategy is developed for permanent magnet synchronous motor (PMSM) drive systems with DC-link voltage sensorless. Generally a DC-link voltage sensor is indispensable for PMSM drive fed by voltage source inverter (VSI) to implement MPCC. In response to DC-link voltage sensor fault, by combination of MRA and sliding-mode techniques, a novel sliding-mode MRA observer for estimating DC-link voltage is proposed to perform MPCC. Moreover, in view of the variation of system parameters and external disturbance, a new nonlinear exponential function-based sliding-mode (NEFSM) speed regulator is synthesized to enhance the system robustness. In order to reduce the drive current ripple and improve speed & torque control performance, MPCC strategy is employed. The resultant NEFSM-based MPCC PMSM drive system with sliding-mode MRA Observer has excellent dynamical performance. In comparison with PI-based MPCC PMSM drive system with sliding-mode MRA observer, the proposed NEFSM-based one possesses better dynamical response and stronger robustness in the presence of variation of load torque. Numerical simulation validates the feasibility and effectiveness of the proposed scheme.
Thanh Tu, DT, Ngoc, NT, Zhu, F, Nguyen, DN, Dutkiewicz, E & Van Yem, V 1970, 'Quad-band antenna for GSM/WSN/WLAN/LTE-A application in IoT devices', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, Australia.
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We designed, fabricated, and experimented a quad-band Double-PIFA (Planar Inverted-F Antenna) for Internet of Things (IoT) applications. Using the Double-PIFA structure allowed us to fabricate the antenna easily and optimize the operating bands for desired frequencies. Combining DGS (Defected Ground Structure) and two shorting pin of PIFA structure, the antenna is compact in size with radiating patch of 184 mm2 basing on RO4350B substrate with height of 1.52 mm. Operating at 900MHz, 1.8GHz, 2.6GHz and 5GHzwith large bandwidth of 6.67%, 11.11%, 5.77% and 16%, respectively. As the proposed antenna can operate for ZigBee, Z-Wave, RFID (Radio-Frequency Identification), WLAN (Wireless Local Area Network), and LTE-A (Long Term Evolution - Advanced), it is suitable for both IoT devices and wide-band wireless communication systems.
Tian, J, Liu, R-P & Lin, S-J 1970, 'A Markov Chain Analysis Model of IEEE 802.11p', Proceedings of the 2017 International Conference on Wireless Communications, Networking and Applications, WCNA 2017: 2017 International Conference on Wireless Communications, Networking and Applications, ACM, Shenzhen, China, pp. 1-5.
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© 2017 Association for Computing Machinery. Quality of Service (QoS) is a critical issue for the broadcast scheme of IEEE 802.11p systems in Vehicular Ad hoc Networks (VANETs)1. We present a 3-dimensional (3-D) Markov chain model to accurately solve for the broadcast scheme of 802.11p systems. The 3th dimension models remaining frozen time in the deferring period. The 3-D model solutions are validated by key simulations. Our analyses reveal that the lack of retransmission in the 802.11p system results in poor QoS performance during heavy traffic load, particularly for large VANETs.
Trad, JJ, Zeb, BA, Esselle, KP & Afzal, MU 1970, 'Preliminary investigations into a simple and effective rectenna for RF energy harvesting', 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2017 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, IEEE, San Diego, CA, pp. 1095-1096.
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Ullah, A, Lie, TT, Gunawardane, K & Nair, NKC 1970, 'Mitigation of residual flux for high-temperature superconductor (HTS) transformer by controlled switching of HTS breaker arc model', 2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), 2017 IEEE Innovative Smart Grid Technologies - Asia (ISGT-Asia), IEEE.
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Ullah, A, Lie, TT, Gunawardane, K & Nair, NKC 1970, 'The improvement of Rate of Rise of Recovery Voltage (RRRV) for an HTS breaker', 2017 IEEE Manchester PowerTech, 2017 IEEE Manchester PowerTech, IEEE.
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Umair, A, Nanda, P & He, X 1970, 'Online social network information forensics: A survey on use of various tools and determining how cautious facebook users are?', Proceedings - 16th IEEE International Conference on Trust, Security and Privacy in Computing and Communications, 11th IEEE International Conference on Big Data Science and Engineering and 14th IEEE International Conference on Embedded Software and Systems, Trustcom/BigDataSE/ICESS 2017, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, Sydney, Australia, pp. 1139-1144.
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© 2017 IEEE. Online Social Networks (OSN) such as Facebook, Twitter, LinkedIn, and Instagram are heavily used to socialize, entertain or gain insights on people behavior and their activities. Everyday terabytes of data is generated over these networks, which is then used by the businesses to generate revenue or misused by the wrongdoers to exploit vulnerabilities of these social network platforms. Specifically social network information helps in extracting various important features such as; user association, access pattern, location information etc. Recent research shows, many such features could be used to develop novel attack models and investigate further into defending the users from exposing their information to outsiders. This paper analyzes some of the available tools to extract OSN information and discusses research work on similar type of unstructured data. Recent research works, which focus on gathering bits and pieces of information to extract meaningful results for digital forensics, has been discussed. An online survey is conducted to gauge the cautiousness of users in social media usage in terms of personal information dissemination.
Vo, BT, Nguyen, HH & Tuan, HD 1970, 'Constellation Design for Quadrature Spatial Modulation', 2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), 2017 IEEE 86th Vehicular Technology Conference (VTC-Fall), IEEE, Toronto, ON, Canada, pp. 1-5.
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© 2017 IEEE. This paper considers constellation design for quadrature spatial modulation (QSM) to minimize the average probability of error. Different than the constellation design previously obtained for spatial modulation (SM), it is shown that, the error performance of QSM not only depends on the Euclidean distances between the amplitude-phase modulation (APM) symbols and the energies of APM symbols, but also on the in-phase and quadrature components of the QSM symbols. The analysis of the union bound of the average error probability reveals that at a very large number of transmit antennas, the optimal constellations for QSM converge to a quadrature phaseshift keying (QPSK) constellation. Simulation results demonstrate the performance superiority of the obtained constellations over the standard PSK and QAM constellations, as well as the constellations specifically designed for SM.
Wan, X, Li, Y, Zhang, C, Yang, Q & Zhu, J 1970, 'Field-circuit coupled T-S finite element analysis of core losses for induction motor', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. A two-dimensional (2-D) field-circuit coupled finite element model of induction motor (IM) is built. The equivalent circuit of three-phase squirrel cage rotor is modeled. Based on time-stepping finite elements analysis (T-S FEA), core loss in the stator of a no-load IM under sinusoidal and Sinusoidal Pulse Width Modulation (SPWM) excitations is studied. The rotating flux density distributions with time variation at different locations of the stator are obtained. Meanwhile, the waveform and trajectory of magnetic flux density are analyzed. The areas where high-order harmonics mainly concentrated are simulated and the core losses in terms of the Bertotti's three-term separation model are calculated. All presented computations and models are verified through experiments.
Wang, A, Huang, P & Zhu, J 1970, 'An optimal frequency division control for hybrid energy storage', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. In this paper, considering the change rate of the load, a frequency division control is optimized to improve the control accuracy of hybrid energy storage, compared to the traditional frequency division control. Firstly, the optimal control strategy is designed based on the first power allocation and the second power allocation. Secondly, the model is applied in residential area to avoid the peak load through simulation. The simulation results are in agreement with the theoretical analysis, which verifies the correctness of the control strategy.
Wang, A, Zhang, J & Zhu, J 1970, 'Research on an improved virtual flux droop control method with better dynamic and static performance', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. In virtual flux droop method, power sharing is achieved by adjusting flux amplitude and angle which has some advantages of simplicity of control and lower voltage and frequency deviation. In this paper, a switch module of power calculation was firstly designed to balance system dynamic response and power fluctuation in flux droop controller. Then an improved direct flux controller was proposed to reduce the flux pulsation by tighter flux linkage control. At last, simulation results prove that the improved virtual flux droop method has better dynamic and static performance.
Wang, H, Dutkiewicz, E, Jayawickrama, BA & Mueck, MD 1970, 'Design of Contour Based Protection Zones for Sublicensing in Spectrum Access Systems', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, NSW, Australia, pp. 1-5.
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© 2017 IEEE. Spectrum Access System (SAS) allows incumbent military systems to share spectrum in a hierarchical manner with tier-2 Priority Access License (PAL) users and tier-3 General Authorized Access (GAA) users. FCC has recently allowed PAL owners to sublicense their channels. Therefore, when GAA channels are congested they can request a sublicense to access the PAL channel on a coordinated basis, which provides interference protection from other GAA users. In this paper, we propose a grid map to measure and monitor the secondary spectrum market for the purpose of spectrum trading with QoS guarantee. This work provides the subsequent spectrum trading models with a reasonable and dedicated interference graph for further optimization of spectrum allocation. Compared with traditional longterm spectrum licensing policy, short-term licensing makes the spectrum allocated effectively. We find the optimal resolution of the discrete grid map that maximizes the profit from sublicensing. Simulation results are provided to demonstrate how fine to grid the region and let the PAL owner achieve monetary benefit, in a given number of sensors.
Wang, H, Dutkiewicz, E, Jayawickrama, BA & Mueck, MD 1970, 'Detection of contour boundary for sublicensing in spectrum access systems', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, QLD, Australia, pp. 1-5.
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© 2017 IEEE. Associated to database and a local centralized system, the short-term spectrum sublicensing is one of the potential approaches to improve the spectrum efficiency in the 5G networks. If the sublicences are assigned to the heterogeneous base stations that are from different operators, the interference issue becomes challenging to tackle. In this paper, we propose a solution of contour boundary detection for sublicensing to coordinate the interference among heterogeneous base stations in the space domain. As the direct access points to sever the end users, the base stations know and even could predict the traffic requirements over their coverage areas. Therefore, we enable individual base station as a sublicensee based on self-reported protection contour and optimize the best allocation for the system to guarantee the interference-free operations among those who spatially use the same sublicense simultaneously. Considering the selfish behaviours of base stations, we employ the sensor networks to monitor and measure their contours. Then we estimate the contour boundary by detecting the inner and outer contour boundary. Finally we compare the estimation accuracies of different sensor networks and demonstrate an interference-free allocation for the sublicensees.
Wang, H, Dutkiewicz, E, Nguyen, D & Mueck, MD 1970, 'Game theoretic analysis of sublicensing for PAL and GAA bands in spectrum access system', 2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 2017 IEEE 28th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), IEEE, Montreal, QC, Canada, pp. 1-5.
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© 2017 IEEE. Motivated by recent efforts in enabling economic models for spectrum sharing systems, in particular, for the Spectrum Access System in the US, we propose a game theoretic analysis of sublicensing between two types of access methods in such system - PAL and GAA. The aim of this paper is to illustrate how the operators' strategies affect their own payoffs and the overall utility in the Sublicenseing Game in a spectrum sharing system. We consider the problem of spectrum sharing among multiple operators who have to pay for a temporary PAL sublicense with the exclusive right to the PAL band or stay in the GAA band and share the spectrum for free with other GAA users. We first formulate this scenario as a non-cooperative game, and then study the existence of a Nash equilibrium. Finally, to reduce the overall utility loss we let the spectrum sharing platform to coordinate individual operators by forming pair coalitions for them. According to our findings, when an operator has a large number of subscribers GAA band is the best response and a high PAL sublicense price holds back operators to access the PAL band. Additionally, making equal coalitions among operators can avoid overall utility loss.
Wang, S, Guo, Y & Dorrell, D 1970, 'Analysis of rectangular EV inductive charging coupler', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 285-291.
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© 2017 IEEE. The number of commercial electric vehicles has increased significantly in recent years. However, there are still limited recharging facilities for EVs. Wireless charging offers an alternative way to recharge with more flexibility and convenience. The wireless transformer/coupler is the key component in electric vehicle wireless charging. The maximum power transfer capability is limited by the coupler. In order to reach desired power transfer level, the parameters of the wireless transformer should be analyzed. The wireless power transfer system design also requires accurate coupler parameters. In this paper, rectangular pads with different size of ferrite bars were analyzed in finite element analysis software. The prototype was built to valid the simulation result.
Wang, T & Zhu, J 1970, 'Finite-control-set model predictive direct torque control with extended set of voltage space vectors', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. The finite-control-set model predictive direct torque control (FCS-MPDTC) is a novel and promising control scheme for permanent magnet synchronous motors (PMSMs). An important feature of FCS-MPDTC is that the eight possible voltage space vectors or switching combinations of the power converters are directly taken into account as the control input of the system. Due to the considerable torque and flux ripples, to improve the performance of FCS-MPDTC, this paper presents an extended set of twenty modulated voltage space vectors with fixed duty ratio. To mitigate the computational burden caused by increased number of voltage space vectors, a pre-selective scheme is designed for the proposed FCS-MPDTC to filter out the impractical voltage vectors instead of evaluating all twenty voltage space vectors. The drive system efficiency of conventional direct torque control (DTC), conventional FCS-MPDTC and proposed method are investigated. A stator current minimisation scheme is also proposed to further increase the system efficiency.
Wang, T, Guo, Y & Zhu, J 1970, 'Finite-control-set model predictive direct torque control of PMSMs with virtual space vectors', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 1427-1430.
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© 2017 IEEE. The finite-control-set model predictive direct torque control (FCS-MPDTC) is a novel control scheme. A key feature of FCS-MPDTC is that the possible voltage space vectors of the power converters are taken into account as the control input of the drive system. A cost function is used in FCS-MPDTC to evaluate each possible voltage space vector and the one with minimum cost is selected. Due to the noticeable torque and flux ripples of FCS-MPDTC, a novel FCS-MPDTC with virtual voltage space vectors is proposed in this paper. To mitigate the computational burden caused by increased voltage space vectors, a pre-selective scheme is designed to filter out the impractical voltage vectors instead of evaluating all twenty voltage space vectors.
Wang, TQ & Huang, X 1970, 'Dimming Compatible Optical OFDM for High Speed Visible Light Communications', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. In this paper, we study a novel optical orthogonal frequency division multiplexing (OFDM) scheme, fractional reversed polarity optical OFDM (FRPO- OFDM), which enables dimmable visible light communications. The scheme combines an asymmetrically clipped optical OFDM (ACO-OFDM) sequence with an information-carrying brightness control sequence (BCS). We show that the new scheme can create a wide range of brightness levels whilst transmitting extra information using the BCS to enhance the spectral efficiency. The detector which can recover information from both sequences is derived based on maximum likelihood (ML) detection and estimation. It is shown that the information carried by the BCS using variable on-off keying (VOOK) can be detected with extremely low bit error rate (BER) and that the resulting overall BER of FRPO-OFDM is constant over a wide dimming range.
Wang, X, Cheng, E & Burnett, IS 1970, 'Improved cell segmentation with adaptive bi-Gaussian mixture models for image contrast enhancement pre-processing', 2017 IEEE Life Sciences Conference (LSC), 2017 IEEE Life Sciences Conference (LSC), IEEE, Sydney, NSW, Australia, pp. 87-90.
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© 2017 IEEE. The accurate detection and segmentation of cells from time-lapse microscopic video sequences provides a critical foundation for understanding dynamic cell behaviours and cell characteristics when using automatic cell tracking systems. However, general object segmentation methods in computer vision are susceptible to errors due to the severe microscopic imaging conditions in time-lapse cell videos. To address the low image intensity contrast typical in cell images, this paper investigates the use of an adaptive, shifted bi-Gaussian mixture model to enhance the contrast prior to cell segmentation. Rather than using a model with fixed parameters across an entire video sequence as in existing approaches, this paper proposes the adaptive derivation of the mixture model parameters to match the intensity histogram for each video frame to adaptively address changes in the video background. Experimental results across a cell database show improved segmentation accuracy compared with existing image contrast enhancement methods. The pre-processed cell image exhibits greater differentiation between the cell foreground and background, whilst also maintaining the original intensity histogram features.
Wang, X, Cheng, E, Burnett, IS, Huang, Y & Wlodkowic, D 1970, 'Crowdsourced generation of annotated video datasets: A zebrafish larvae dataset for video segmentation and tracking evaluation', 2017 IEEE Life Sciences Conference (LSC), 2017 IEEE Life Sciences Conference (LSC), IEEE, Sydney, NSW, Australia, pp. 274-277.
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© 2017 IEEE. Video segmentation research has emerged over the last decade for biomedical image and video processing, especially in biological organism tracking. However, due to the difficulties in generating the video segmentation ground truth, the general lack of segmentation datasets with annotated ground-truth severely limits the evaluation of segmentation algorithms. This paper proposes an efficient and scalable crowdsourced approach to generate video segmentation ground-Truth to facilitate database generation for general biological organism segmentation and tracking algorithm evaluation. To illustrate the proposed approach, an annotated zebrafish larvae video segmentation dataset has been generated and made freely available online. To enable the evaluation of algorithms against a ground-Truth, a set of segmentation evaluation metrics are also presented. The segmentation performance of five leading segmentation algorithms is then evaluated by the metrics on the generated zebrafish video segmentation dataset.
Wang, Z & Piccardi, M 1970, 'Dissimilarity-based action recognition with the pair hidden Markov support vector machine', 2017 IEEE 19th International Workshop on Multimedia Signal Processing, IEEE International Workshop on Multimedia Signal Processing, IEEE, Luton, UK, pp. 1-6.
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Human action recognition in video is highly challenging due to the substantial variations in motion performance, recording settings and inter-personal differences. Most current research focuses on the extraction of effective features and the design of suitable classifiers. Conversely, in this paper we tackle this problem by a dissimilarity-based approach where classification is performed in terms of minimum distance from templates. To measure the dissimilarity between any two action instances, we propose leveraging the Pair Hidden Markov Support Vector Machine (PHMM-SSVM) that was recently proposed for tasks of video alignment. The main advantages of PHMM-SSVM are its ability to learn optimal alignment models from training sets of manually-aligned action pairs and provide alignment scores that can be used for action classification. The experimental results over two popular action datasets show that the proposed approach has been capable of achieving an accuracy higher than many existing methods and comparable to a state-of-the-art algorithm.
Wazirali, R, Chaczko, Z & Chiang, E 1970, 'Steganographic Authentication in Cloud Storage for Mitigation of Security Risks', 2017 25th International Conference on Systems Engineering (ICSEng), 2017 25th International Conference on Systems Engineering (ICSEng), IEEE, Las Vegas, NV, USA, pp. 451-458.
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© 2017 IEEE. Identity theft is a serious crime where the criminals steal user's identity to access their bank accounts, personal hospital records and etc. The usage of cloud storage has allowed the hackers to attack the victims easily by accessing the victim's data stored in a remote location. Cloud storage may be convenient to allow users to store any data files and access those files from different devices and in different locations around the world. However, it can still pose security threats as with a lot of important data stored in one location is very appealing to cunning hackers. The solution of using image steganography application to hide important data or documents under an image before uploading them to the cloud storage will avoid the risks of attracting hackers or outsiders to discover the importance of the data hidden. The application uses one of simplest image steganography approach 'LSB algorithm' to achieve best quality of encoded image/stego-image. Besides, the application can be deployed via offline or online depending whether they want to upload the encoded image/stego-image to the cloud storage.
Wazirali, R, Chaczko, Z & Gibbon, J 1970, 'Steganographic Image Sharing App', 2017 25th International Conference on Systems Engineering (ICSEng), 2017 25th International Conference on Systems Engineering (ICSEng), IEEE, Las Vegas, NV, USA, pp. 494-499.
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© 2017 IEEE. With the advent of smartphones, many people have the ability to take a photo and upload it to the internet whenever they want. Most smartphones will include basic metadata in the image file; however, this is usually limited to information about the camera itself, and not the content of the photo. This data is also easy to access, as there are many websites and applications that will extract the metadata from an image, thus it is unsuitable for personal information. While there are many applications out there which will allow a user to take and upload photos for their friends or the public to view, such as Facebook or Instagram, these applications rely on information provided along side the image for privacy settings, commenting, and image searching. Other search engines would have difficulty categorising the pictures they find on various sites, and if the image is saved and re-uploaded somewhere else, the information about them would likely be lost. Steganography provides a feasible and viable solution to these problems. By embedding information directly into the image, the information about the image will not be lost, if it is separated from its original source. The aim of the capstone is to demonstrate this aspect via an image sharing app that allows users to exchange messages and personalised information that is embedded in the image such that it is inaccessible without knowing their keys, and metadata that can be used by search engines to categorise the image and its contents. The developed application will provide a platform for users to create an account, share images, embed information within the image, and search for images other users have uploaded.
Wei, X, Cheng, M, Hua, W, Zhu, J & Yang, H 1970, 'Model predictive power control of a brushless doubly fed twin stator induction generator', 2017 IEEE Energy Conversion Congress and Exposition (ECCE), 2017 IEEE Energy Conversion Congress and Exposition (ECCE), IEEE, Cincinnati, OH, USA, pp. 5080-5085.
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© 2017 IEEE. This paper presents a model predictive power control (MPPC) scheme for the brushless doubly fed twin stator induction generator (BDFTSIG). State-space equations of the BDFTSIG, in terms of power winding (PW) current, control winding (CW) current, and PW flux, is specifically derived. A complete power model, which clearly reveals the relationship between power and the applied voltage vector, is then developed for the first time to accurately predict the future behavior of power. The proposed MPPC is realized by optimizing a predefined objective function that represents the absolute power error. It takes into account the discrete nature of power converters and does not require any additional modulator. Digital simulations are implemented, which clearly indicate the effectiveness of the proposed MPPC in terms of both steady-state and dynamic performance.
Wei, X, Zhu, J, Cheng, M, Yang, H & Ma, B 1970, 'Model predictive control of brushless doubly fed twin stator induction machine: A model reduction approach', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia`, pp. 1-6.
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© 2017 IEEE. This, paper presents a model predictive control (MPC) scheme and its model reduction approach for the brushless doubly fed twin stator induction machine (BDFTSIM). Firstly, the state-space equations of BDFTSIM, in terms of (power winding) PW flux, (rotor winding) RW flux, and (control winding) CW flux, is derived for developing the complete power model which is explicitly used to predict the future behavior. However, the MPC based on the complete model is too complicated for real time application. Therefore, a relevant model reduction approach is then developed for simplifying the power model while maintaining the accuracy under various conditions. Finally, by comparing the simulation results of the MPC based on the reduced model and complete model respectively, the effectiveness of the proposed method is verified.
Wu, G, Liu, RP, Ni, W & Xu, P 1970, 'Modeling CCH Switch to SCH in IEEE 802.11p/WAVE Vehicular Networks', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, NSW, Australia, pp. 1-5.
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© 2017 IEEE. Packet collision and packet delay are considered to be critical for safety applications in vehicular networks. This paper designs a new analytical model to evaluate the performance of channel switching for IEEE 802.11p/WAVE in vehicular networks. Under this model, it explicitly expresses the WAVE channel switching, and constructs contention window size and number of vehicles as packet collision probability and packet delay time function of variables. Finally, we evaluate accuracy of the designed model of collision caused by channel switching and transmission delay in vehicular networks. The results show that the model could analyzes perfectly packet collision which is caused by channel switching and packet delay in vehicular networks.
Wu, T, Fu, K, Zhu, J & Lei, G 1970, 'The influence analysis of thrust and gap magnetic field of a down-to-hole tubular permanent magnet linear hammer due to high temperature in deep hole', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia.
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© 2017 IEEE. Recently a novel electric hammer driven by tubular permanent magnet linear synchronous motor (TPMLSM) has arouse great interest among researchers in the field of deep drilling for its distinctive advantages compared with hydraulic and pneumatic hammers. The working temperature in deep down-hole is relatively high, so the research of the influence of high temperature in deep hole on the electromagnetic thrust of the linear motor is very important. In this paper, a numerical electromagnetic calculation model of the thrust of the hammer was established to analyze the influence as a result of the loss of permanent magnet, coil resistance variation and coil volume expansion due to the temperature variation from 20°C to 300°C. The calculated results showed from 20°C to 300°C, the increase of the copper loss reduced the thrust by 31%, the loss of permanent magnets reduced the thrust by 18%. And the effect of the air-gap variation by thermal expansion can be neglected.
Wu, W, Liu, R, Ni, W, Kaafar, D & Huang, X 1970, 'AC-PROT: An Access Control Model to Improve Software-Defined Networking Security', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. The logically-centralized controllers have largely operated as the coordination points in software-defined networking(SDN), through which applications submit network operations to manage the global network resource. Therefore, the validity of these network operations from SDN applications are critical for the security of SDN. In this paper, we analyze the mechanism that generates network operations in SDN, and present a fine-grained access control model, called Access Control Protector(AC-PROT),that employs an attribute-based signature scheme for network applications. The simulation result demonstrates that AC-PROT can efficiently identify and reject unauthorized network operations generated by applications.
Xia, H, Zhao, W, Zhou, Z, Jiang, F, Li, H & He, X 1970, 'Deformable Template Matching Using Proposal-Based Best-Buddies Similarity', 2017 IEEE Trustcom/BigDataSE/ICESS, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, Sydney, pp. 517-521.
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© 2017 IEEE. We propose a new method for template matching based on the Best-Buddies Similarity (BBS) measure. Our method is able to match objects with large difference in size and hence achieves a deformable template matching. In addition, compared with the original method for template matching based on the BBS, our method significantly cuts down on the computation time. The fast and deformable template matching is implemented by measuring the BBS of only potential areas instead of all positions in an image. The potential areas, which can have different size from the given template, are found by a proposal generation based on edge priors and a selective search among the obtained proposals. The results from the experiments conduct-ed on a challenging dataset demonstrate that our method out-performs the state-of-the-art methods in terms of accuracy.
Xin, J-N, Du, X & Zhang, J 1970, 'Deep learning for robust outdoor vehicle visual tracking', 2017 IEEE International Conference on Multimedia and Expo (ICME), 2017 IEEE International Conference on Multimedia and Expo (ICME), IEEE, Hong Kong, China, pp. 613-618.
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© 2017 IEEE. Robust visual tracking for outdoor vehicle is still a challenging problem due to large appearance variations caused by illumination variation, occlusion and scale variation, etc. In this paper, a deep-learning-based approach for robust outdoor vehicle tracking is proposed. Firstly, a stacked denoising auto-encoder is pre-trained to learn the feature representation way of images. Then, a k-sparse constraint is added to the stacked denoising auto-encoder and the encoder of k-sparse stacked denoising auto-encoder (kSSDAE) is connected with a classification layer to construct a classification neural network. After fine-tuning, the classification neural network is applied to online tracking under particle filter framework. Extensive tracking experiments are conducted on a challenging single object online tracking evaluation platform benchmark to verify the effectiveness of our tracker. Experiments show that our tracker outperforms most state-of-the-art trackers.
Xiong, H, Zhu, J, Shi, J, Meng, S & Luo, X 1970, 'Design of a three dimensional magnetic field measurement system for TMS pre-testing', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. In the course of treatment and diagnosis of transcranial magnetic stimulation (TMS), the target and non-target are stimulated simultaneously, which produces undesirable side effects. To reduce the risk of such side effects, it is essential to test the stimulation before the real treatment. This paper presents the structure of a magnetic field measurement system for TMS pre-testing. The 3D magnetic field measurement structure can use a 3D magnetic sensor to measure the value of electromagnetic field in some specific points of the brain model to reduce the risk that could be caused by directly measuring in human brain and effectively avoid the side effects of TMS.
Yang, Y, Zhu, X & Xue, Q 1970, 'On-chip circuit miniaturization techniques for millimeter-wave bandpass filter design', 2017 10th Global Symposium on Millimeter-Waves, 2017 10th Global Symposium on Millimeter-Waves (GSMM), IEEE, Hong Kong, pp. 24-27.
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© 2017 IEEE. In this paper, the millimeter-wave circuit miniaturization techniques using BCMLR and interdigital resonators are introduced. Using these structures, the physical size of the on-chip filter can be dramatically reduced. The designed BPFs are implemented in standard 0.13-μm SiGe and 0.1-μm GaAs technologies for concept approval. Compared with other state-of-the-art work at millimeter-wave frequencies, our proposed designs have the merits of ultra-compact size as small as 0.038 mm2, competitive insertion loss (1 dB in GaAs BPF) and harmonic suppression of more than 44 dB.
Yang, Z, Zhang, D, Sun, X, Sun, W, Zhu, J & Guo, Y 1970, 'Vector control for a bearingless induction motor based on nonsingular terminal sliding mode structure', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia.
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© 2017 IEEE. To improve the performance of the bearingless induction motor (BIM) under disturbances, a nonsingular fast terminal sliding mode control (NFTSMC) strategy is proposed. The sliding mode surface is designed as a combination of linear sliding mode and nonsingular terminal sliding mode. Besides, considering the power function of the state variables, which make the approaching speed correlate with the state variables, so as to improve convergence performance of the linear sliding mode and solve the singularity of terminal sliding mode. Meanwhile, current signal and radial force are extracted by the electromagnetic torque and the equation of l evitation force. Therefore, the convergence speed of system can be accelerated during the whole process, which contributes to chattering-free operating. The simulation and experiment results indicate that the proposed method can not only track the given value of the speed and radial displacement quickly, but also improve the operation quality and enhance the system robustness.
Yanjie Dong, Hossain, J, Julian Cheng & Leung, VCM 1970, 'Joint RRH selection and beamforming in distributed antenna systems with energy harvesting', 2017 International Conference on Computing, Networking and Communications (ICNC), 2017 International Conference on Computing, Networking and Communications (ICNC), IEEE, pp. 582-586.
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© 2017 IEEE. To reduce the transmission power while maintaining quality of service requirements of users, more remote radio heads (RRHs) should be active, and this in turn increases the circuit power in the distributed antenna systems with simultaneous wireless information and power transferring. Yet, the above procedures may lead to an unbalanced power consumption between transmission and circuit; therefore causes extra burden on the operators' power budget. To obtain a balanced transmission power and circuit power, this paper studies the system utility minimization problem in such a system via joint RRH selection and beamforming. The utility is formulated as the weighted sum of transmission power and circuit power. Since the formulated problem is NP-hard, a low complexity iterative algorithm is developed to achieve a near-optimal solution. The complexity of each iteration step is analyzed. Computer simulation results show the convergence of the proposed algorithm and the tradeoff between the transmission power and the circuit power.
Yao, L, Kusakunniran, W, Wu, Q, Zhang, J & Tang, Z 1970, 'Robust Gait Recognition under Unconstrained Environments Using Hybrid Descriptions', 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), IEEE, Sydney, Australia, pp. 1-7.
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© 2017 IEEE. Gait is one of the key biometric features that has been widely applied for human identification. Appearance-based features and motion-based features are the two mainly used presentations in the gait recognition. However, appearance-based features are sensitive to the body shape changes and silhouette extraction from real-world images and videos also remains a challenge. As for motion features, due to the difficulty in extracting the underlying models from gait sequences, the localization of human joints lacks of high reliability and strong robustness. This paper proposes a new approach which utilizes Two-Point Gait (TPG) as the motion feature to remedy the deficiency of the appearance feature based on Gait Energy Image (GEI), in order to increase the robustness of gait recognition under the unconstrained environments with view changes and cloth changes. Another contribution of this paper is that this is the first time that TPG has been applied for view change and cloth change issues since it was proposed. The extensive experiments show that the proposed method is more invariant to the view change and cloth change, and can significantly improve the robustness of gait recognition.
Ye, L, Argha, A, Celler, BG, Zhang, Y, Nguyen, HT & Su, SW 1970, 'Nonparametric modelling of VO<inf>2</inf> response to exercise', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Jeju Island, Korea, pp. 1525-1528.
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This paper investigates the modelling of oxygen
consumption (VO2) response to jogging exercise on treadmill.
Unlike most of the previous methods, which often use simple
parametric models, e.g., first order linear time invariant model,
this study applied a nonparametric kernel based regularised
method to estimate VO2 to address the ill-conditioned modelling
problem and achieve accurate estimation. In particular, it is
worthy to be noted that the selection of kernels will affect
the results for different modelling scenarios. Therefore, in this
research, both radial basis kernel and stable spline kernel were
selected for testing. In order to select the favourable kernel
for this system, a simulation related to VO2-jogging speed was
carried out. The results of simulation indicated that spline
kernel can achieve higher accuracy comparing to radial basis
function kernel. Experimentally, the kernel based estimation
method and spline kernel were tested using six participants.
From the results, an average impulse response is obtained. It
showed the VO2 estimation, based on the average finite impulse
response, is fitted well to the six observations collected from the
participants.
Yu, H, Guo, K, Luo, J, Cao, K, Nguyen, HT & Su, SW 1970, 'The classification for “equilibrium triad” sensory loss based on sEMG signals of calf muscles', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Jeju Island, Korea, pp. 2143-2145.
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Surface Electromyography (sEMG) has been commonly applied for analysing the electrical activities of skeletal muscles. The sensory system of maintaining posture balance includes vision, proprioception and vestibular senses. In this work, an attempt is made to classify whether the body is missing one of the sense during balance control by using sEMG signals. A trial of combination with different features and muscles is also developed. The results demonstrate that the classification accuracy between vision loss and the normal condition is higher than the one between vestibular sense loss and normal condition. When using different features and muscles, the impact on classification results is also different. The outcomes of this study could aid the development of sEMG
based classification for the function of sensory systems during human balance movement.
Zeng, J, Guo, Y & Zhu, J 1970, 'Investigation and Simulation on Magnetic Hysteresis Properties of Magnetorheological Fluid', IEEE Transactions on Industrial Electronics, Institute of Electrical and Electronics Engineers (IEEE), Annecy, France, pp. 1611-1616.
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Zha, X, Wang, X, Ni, W, Liu, RP, Guo, YJ, Niu, X & Zheng, K 1970, 'Analytic model on data security in VANETs', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, QLD, Australia, pp. 1-6.
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© 2017 IEEE. Fast-changing topologies and uncoordinated transmissions are two critical challenges of implementing data security in vehicular ad-hoc networks (VANETs). We propose a new protocol, where transmitters adaptively switch between backing off retransmissions and changing keys to improve success rate. A new 3-dimensional (3-D) Markov model, which can analyze the proposed protocol with symmetric or asymmetric keys in terms of data security and connectivity, is developed. Analytical results, validated by simulations, show that the proposed protocol achieves substantially improved resistance against collusion attacks.
Zhan, Y, Guo, Y, Zhu, J & Li, L 1970, 'Input current ripple reduction and high efficiency for PEM fuel cell power conditioning system', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-6.
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© 2017 IEEE. To solve the issues of the open-loop control accuracy in a proton exchange membrane (PEM) fuel cell power conditioning system (PCS) with active clamp push-pull DC/DC converter for input current ripple reduction, a novel closed-loop digital-controlled method is proposed. The proposed PEM fuel cell PCS consists of a high-efficiency high-step-up current-fed resonant push-pull DC/DC converter and a half-bridge inverter. A fully digital-controlled strategy in the active-clamped circuit is employed to reduce the voltage spike and low frequency current ripple (LFCR) on the power switches for improving the lifespan of PEM fuel cell and raising the system reliability. By using the closed-loop current ripple reduction control, the LFCR is further reduced. A 300 W prototype is implemented and tested. Experimental results show that the minimum efficiency at full load is about 94.8% and the ripple current is less than 1.2% of the rated input current.
Zhang, G & Kleijn, WB 1970, 'Training Deep Neural Networks via Optimization Over Graphs', Proceedings of international on acoustics, Speech, and Signal Processing, International Conference on Acoustics, Speech, and Signal Processing, Calgary, Canada.
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In this work, we propose to train a deep neural network by distributedoptimization over a graph. Two nonlinear functions are considered: therectified linear unit (ReLU) and a linear unit with both lower and uppercutoffs (DCutLU). The problem reformulation over a graph is realized byexplicitly representing ReLU or DCutLU using a set of slack variables. We thenapply the alternating direction method of multipliers (ADMM) to update theweights of the network layerwise by solving subproblems of the reformulatedproblem. Empirical results suggest that the ADMM-based method is less sensitiveto overfitting than the stochastic gradient descent (SGD) and Adam methods.
Zhang, H, Huang, X & Guo, YJ 1970, 'A 20 Gbps Digital Modem for High Speed Wireless Backhaul Applications', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE.
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© 2017 IEEE. The rapid growth of mobile broadband wireless services in recent years demands high speed data transmission for both access and backhaul networks. With the increase of data rate for 5G access to tens of Gigabits per second (Gbps), higher speed transmission for backhaul network is necessary. Current wireless backhaul systems have been able to achieve the data rate of multiple Gbps, but the ability to deal with significant practical impairments such as large carrier frequency offset and IQ mismatch is still a technical challenge. In this paper, a 20 Gbps digital modem for wireless backhaul applications is proposed. Simulation and field programmable gate array implementation show that the the proposed design and signal processing algorithms meet the targeted system performance.
Zhang, J, Li, L, Dorrell, D & Guo, Y 1970, 'A PI controller with current feedforward to improve the steady-state error performance for a current controlled direct matrix converter', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, pp. 1-6.
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© 2017 IEEE. Traditional PI controllers can have poor regulation performance due to steady state errors when tracking sinusoidal signals. Hence synchronous PI controllers are often used, although this controller requires reference frame transformations. In this paper, a modified PI controller, which uses current feedforward, is developed to control the output currents of a matrix converter. The controller is implemented in the natural frame (abc) together with space vector modulation. The output current is then controlled. This controller does not require any frame transformation and it demonstrates improved steady-state tracking performance. The total harmonic distortion is improved at the same time. A constant switching frequency is maintained because of the application of the modulation stage. Simulation results verify the feasibility and effectiveness of the proposed controller.
Zhang, J, Li, L, Dorrell, D & Guo, Y 1970, 'Direct torque control with a modified switching table for a direct matrix converter based AC motor drive system', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia.
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© 2017 IEEE. The direct matrix converter has been regarded as a promising AC/AC conversion topology and it is being researched. Motor drives are one of the main potential applications of the matrix converter. This paper carries forward the application of matrix converters in AC motor drives using direct torque control (DTC). In the common DTC scheme for the matrix converter, two vectors with the maximum amplitudes are used to control the torque and flux. In the proposed approach, the input voltage vector sectors are redefined, therefore a modified and simplified switching look-up table is obtained. In this case the most appropriate vector to be applied is uniquely determined and the number of switch actions are reduced. The excellent dynamic performance is obtained by selecting the maximum vector. Flux and speed are controlled effectively. Simulation work is carried out for an induction motor and results verify the effectiveness of the proposed DTC control in matrix converter based AC drive systems.
Zhang, J, Li, L, Dorrell, DG & Guo, Y 1970, 'Space vector modulation based proportional resonant current controller with selective harmonics compensation for matrix converter systems', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia.
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© 2017 IEEE. The matrix converter has emerged as a direct AC/AC converter and has attracted research attention. This work proposes a Proportional Resonant (PR) controller based on the Space Vector Modulation (SVM) method for the three-phase direct matrix converter and its application systems. The PR controller, compared with the widely used PI controller, has better steady-state error performance, specific harmonics compensation capability, and the ability to handle sinusoidal quantities. These enhance the tracking performance of the converters and benefit the current quality improvement and selective harmonics suppression. The PR controller can be implemented in the natural frame in a straightforward manner, which removes the frame transformations involved in the stationary (αβ) and synchronous (dq) reference frame based control strategies. This alleviates the computation burden. Simulation results verify the effectiveness of the proposed PR controller for the matrix converter applications.
Zhang, J, Li, L, He, T, Aghdam, MM & Dorrell, DG 1970, 'Investigation of direct matrix converter working as a versatile converter (AC/AC, AC/DC, DC/AC, DC/DC conversion) with predictive control', IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, IEEE, Beijing, China, pp. 4644-4649.
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© 2017 IEEE. The three-phase direct matrix converter has been researched exclusively as a direct AC/AC converter, being a competitive alternative to the conventional AC/DC/AC converter. Other possibilities of the matrix converter such as AC/DC, DC/AC and DC/DC conversion still remain unexplored. This paper firstly explores these possibilities and puts forward a concept of the versatile converter. With one matrix converter, different conversion purposes can be accomplished as required. The matrix converter based conversion has some advantages compared with other converters. Model predictive control (MPC) is applied in this work to control the matrix converter to perform the required conversion goals. A generalized model is obtained for all types of conversion in this work. With MPC, different objectives and constraints can be easily included in the control scheme. In addition, the observers are used to reduce the number of voltage and current sensors. Simulation results verify the effectiveness and feasibility of AC/DC, DC/AC and DC/DC conversion with the matrix converter.
Zhang, J, Li, L, Malekjamshidi, Z & Dorrell, DG 1970, 'Predictive voltage control of direct matrix converter with reduced number of sensors for the renewable energy and microgrid applications', 2017 IEEE Energy Conversion Congress and Exposition (ECCE), 2017 IEEE Energy Conversion Congress and Exposition (ECCE), IEEE, Cincinnati, OH, USA, pp. 3309-3315.
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© 2017 IEEE. This work proposes and investigates a renewable energy distributed generation system involving a matrix converter with an output filter working as a stable voltage supply. This is especially relevant for the stand-alone operation of a renewable energy microgrid where a stable sinusoidal voltage with prescribed amplitude and frequency under various load conditions is the main control objective. A controllable input power factor is preferred. In this paper, the model predictive control is employed to regulate the matrix converter output voltages which in turn are the supply for systems of the following stage. To reduce the number of required measurements and sensors, the work designs observers and makes use of the switch matrix. In addition to the regulation of the sinusoidal output voltages and input power factor, the control scheme deals with the common-mode voltage. The switching frequency is also considered in the controller to reduce the switching losses and keep the average switching frequency constant. In addition, the voltage transfer ratio can be improved at the cost of input current distortion. Supplying DC loads is feasible with this proposed control method. The controller is tested under various conditions including non-linear loads, DC loads and unbalanced input conditions to show it is effective, simple and easy to implement. Simulation results corroborate the effectiveness of the proposed controller and applications.
Zhang, J, Li, L, Zhang, L & Dorrell, DG 1970, 'Hysteresis band current controller based field-oriented control for an induction motor driven by a direct matrix converter', IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, IEEE, Beijing, China, pp. 4633-4638.
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© 2017 IEEE. This paper presents work on the hysteresis band control for output current regulation in a direct matrix converter in order to drive an induction motor. The hysteresis band controller offers excellent dynamic performance. It has been extensively researched for the voltage source inverter and inverter based drive systems, but it has not been investigated within the context of a matrix converter or a matrix converter based motor drive. Firstly, this paper proposes a fixed-band hysteresis current controller for a matrix converter to track the prescribed current references, and then a sinusoidal-band hysteresis current controller is proposed. Both methods have fast dynamic performance and they inherently integrate the line modulation technique of the virtual rectifier stage into the overall modulation. The extra modulation stage is not required and the surge current is inherently prevented. The sinusoidal-band hysteresis controller demonstrates that it generates lower harmonic content at the expense of the higher average switching frequency. Following this, both methods are tested as a drive for an induction motor with field-oriented control. With the matrix-converter-based drive system, one significant benefit is that the braking chopper is removed due to the bidirectional feature. The methods are simple and have light computation burden. The obtained results demonstrate the effectiveness and feasibility of the proposed scheme. The experimental work is being carried out to support the proposed scheme.
Zhang, J, Wu, Q, Zhang, J, Shen, C & Lu, J 1970, 'Kill Two Birds with One Stone: Weakly-Supervised Neural Network for Image Annotation and Tag Refinement', The Thirty-Second AAAI Conference on Artificial Intelligence, The Thirty-Second AAAI Conference on Artificial Intelligence, AAAI Press, USA, pp. 7550-7557.
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The number of social images has exploded by the wide adoption of socialnetworks, and people like to share their comments about them. These commentscan be a description of the image, or some objects, attributes, scenes in it,which are normally used as the user-provided tags. However, it is well-knownthat user-provided tags are incomplete and imprecise to some extent. Directlyusing them can damage the performance of related applications, such as theimage annotation and retrieval. In this paper, we propose to learn an imageannotation model and refine the user-provided tags simultaneously in aweakly-supervised manner. The deep neural network is utilized as the imagefeature learning and backbone annotation model, while visual consistency,semantic dependency, and user-error sparsity are introduced as the constraintsat the batch level to alleviate the tag noise. Therefore, our model is highlyflexible and stable to handle large-scale image sets. Experimental results ontwo benchmark datasets indicate that our proposed model achieves the bestperformance compared to the state-of-the-art methods.
Zhang, J, Zhang, J, Wu, Q, Wu, Q, Xu, J, Lu, J, Phua, R, Curr, K & Tang, Z 1970, 'Historical Image Annotation by Exploring the Tag Relevance', 2017 4th IAPR Asian Conference on Pattern Recognition (ACPR), 2017 4th IAPR Asian Conference on Pattern Recognition (ACPR), IEEE, Nanjing, China, pp. 646-651.
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© 2017 IEEE. Historical images usually contain enormous historical research value and are highly related to the history objects, events and background stories etc. Therefore, annotating these images always requires selecting tags within a large set. In this paper, we propose to annotate historical images by exploring the tag relevance. We measure the tag relevance from three different perspectives, including its visual relevance, its dependencies with other tags and its relationship with location based meta-data. By using tag relevance as guidance, we generate three tag sub-sets and use them to fulfill the annotation. Experimental results on the benchmark dataset indicate the significance of exploring the tag relevance by comparing with the baseline experiments.
Zhang, JA, Cantoni, A, Huang, X, Guo, YJ & Heath, RW 1970, 'Joint Communications and Sensing Using Two Steerable Analog Antenna Arrays', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, Australia.
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© 2017 IEEE. Beam-steering has great potentials for joint communications and sensing, which is becoming a demanding feature on many emerging platforms such as unmanned aerial vehicles and smart cars. Although beam-steering has been extensively studied for communications and radar sensing respectively, its application in the joint system is not straightforward due to different beamforming requirements by communications and sensing. In this paper, we propose a low-cost system framework which allows seamless operation of communications and sensing, using two small- size steerable analog antenna arrays. We provide system architecture, high-level protocols, detailed signal model, novel beamforming design and advanced 1D compressive sensing algorithms for joint communications and sensing. We also provide preliminary simulation results which validate the effectiveness of the proposed technique in resolving closely located objects.
Zhang, JA, Cantoni, A, Huang, X, Guo, YJ & Jr, RWH 1970, 'Framework for an Innovative Perceptive Mobile Network Using Joint Communication and Sensing', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, pp. 1-5.
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In this paper, we develop a framework for an innovative perceptive mobile(i.e. cellular) network that integrates sensing with communication, andsupports new applications widely in transportation, surveillance andenvironmental sensing. Three types of sensing methods implemented in thebase-stations are proposed, using either uplink or downlink multiusercommunication signals. The required changes to system hardware and majortechnical challenges are briefly discussed. We also demonstrate the feasibilityof estimating sensing parameters via developing a compressive sensing basedscheme and providing simulation results to validate its effectiveness.
Zhang, JA, Huang, X, Guo, YJ & Rahman, ML 1970, 'Signal stripping based sensing parameter estimation in perceptive mobile networks', 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Verona, Italy, pp. 67-70.
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© 2017 IEEE. We propose signal stripping based approaches for estimating detailed channel composition parameters for sensing in the recently proposed perceptive mobile networks where simultaneous communication and radar sensing is performed. Via reconstructing a (differentiated) channel matrix, we obtain a signal model which can be solved by conventional compressive sensing (CS) techniques. Parameter estimation methods based on a 1-D CS algorithm are proposed and their effectiveness is validated by provided simulation results.
Zhang, JA, Li, H, Huang, X, Guo, YJ & Cantoni, A 1970, 'User-Directed Analog Beamforming for Multiuser Millimeter-Wave Hybrid Array Systems', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, Australia, pp. 1-5.
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© 2017 IEEE. Beamforming design for millimeter-Wave hybrid array with the subarray structure is very challenging. There is neither known optimal solution that maximizes the sum rate capacity nor near-optimal solution. This paper proposes some low-complexity user-directed analog radio- frequency (RF) beamforming design schemes. The basic idea is to iteratively allocate different subarrays to different users such that users' channel correlation can be efficiently reduced via RF beamforming. Several new but less efficient schemes are also presented to shed light on RF beamforming design, and to serve as comparisons for the user-directed schemes. Simulation results are provided for these proposed schemes, existing ones in the literature and an upper-bound for hybird array with a fully-connected structure. The user-directed schemes demonstrate significantly better sum-rate and BER performance over other schemes, although the gap to the upperbound is still large.
Zhang, M, Li, H & Su, SW 1970, 'An evolutionary algorithm with 2-D encoding for image segmentation', 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia.
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This paper presents an evolutionary approach which treats the image segmentation as a graph partitioning problem. An image is described as a weighted undirected graph where pixels correspond to nodes, and those pixels with similar values and positions are connected by edges. The weighted normalized cut criterion (WNcut) is used in this paper for this graph partitioning problem to measures both the dissimilarity between different partitions and the total similarity within the groups. This paper adopts a 2-dimensional representation of chromosome to directly present an image segmentation which is beneficial both to the genetic operators in the evolutionary process and to efficiently reduce the running time. In addition, the proposed evolutionary algorithm uses prior user's preference information to control the segments of the image through a random walker approach to initialize population. Experimental results demonstrate that our proposed algorithm is able to efficiently handle segmentation cases that segments images into several partitions based on human visual perception. The statistical results of entropy-based evaluation also suggest that our approach could achieve a more accurate segmentation.
Zhang, W, Szymanski, J, Chiu, C, Chaczko, Z, Su, S & Zhou, J 1970, 'How the Internet of Things is Changing Teaching of Technical Subjects at UTS', 5th Asia-Pacific Conference on Computer-Aided System Engineering, Asia-Pacific Conference on Computer Aided System Engineering, APCASE Foundation, Guilin, Guangxi, China, pp. 71-77.
Zhang, Y, Su, S, Xu, P & Yao, D 1970, 'Performance evaluation of Noise-Assisted Multivariate Empirical Mode Decomposition and its application to multichannel EMG signals', 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), IEEE, Seogwipo, South Korea, pp. 3457-3460.
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© 2017 IEEE. The use of the Empirical Mode Decomposition (EMD) for nonlinear signal processing has been popularized in the recent years. However, its utility for the processing of multichannel Electromyography (EMG) signals is still limited. This paper investigates the decomposition performance of multichannel EMGs by using the EMD-based approaches, Ensemble EMD (EEMD), Multivariate EMD (MEMD), and Noise-Assisted MEMD (NA-MEMD). In the experiment, 11 male subjects undergo three exercise programs, leg extension from a sitting position, flexion of the leg up, and gait, while electrodes are placed on the muscle groups, biceps femoris, vastus medialis, rectus femoris, and semitendinosus. The outcomes are then quantitatively estimated on the basis of three criterions, the number of Intrinsic Mode Functions (IMFs), mode-alignment and mode-mixing. Results show both MEMD and NA-MEMD can guarantee equal numbers of IMFs, whereas for mode-alignment and mode-mixing, NA-MEMD is optimal compared with MEMD and EEMD, and MEMD is merely better than EEMD. This finding implies that NA-MEMD is effective for simultaneously analyzing IMFs based frequency bands. It has a vital clinical implication in exploring the neuromuscular patterns that enable the multiple muscle groups to coordinate while performing functional activities of daily living.
Zhao, M, Zhang, J, Porikli, F, Zhang, C & Zhang, W 1970, 'Learning a perspective-embedded deconvolution network for crowd counting', 2017 IEEE International Conference on Multimedia and Expo (ICME), 2017 IEEE International Conference on Multimedia and Expo (ICME), IEEE, Hong Kong, China, pp. 403-408.
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We present a novel deep learning framework for crowd counting
by learning a perspective-embedded deconvolution network.
Perspective is an inherent property of most surveillance
scenes. Unlike the traditional approaches that exploit the perspective
as a separate normalization, we propose to fuse the
perspective into a deconvolution network, aiming to obtain a
robust, accurate and consistent crowd density map. Through
layer-wise fusion, we merge perspective maps at different resolutions
into the deconvolution network. With the injection of
perspective, our network is driven to learn to combine the underlying
scene geometric constraints adaptively, thus enabling
an accurate interpretation from high-level feature maps to the
pixel-wise crowd density map. In addition, our network allows
generating density map for arbitrary-sized input in an
end-to-end fashion. The proposed method achieves competitive
result on the WorldExpo2010 crowd dataset.
Zhao, S, Cheng, E, Qiu, X, Burnett, I & Liu, CC 1970, 'Simulations on the wind noise reduction by spherical shell windscreens', INTER-NOISE 2017 - 46th International Congress and Exposition on Noise Control Engineering: Taming Noise and Moving Quiet.
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Various windscreens are widely used in outdoor acoustic measurements to reduce the effect of the wind induced pressure fluctuations at the microphones and to improve the measurement accuracy. However, the physical mechanism of the wind noise reduction by windscreens remains unclear yet. In this paper, the wind noise reduction performance of spherical shell windscreens is investigatedwith numerical simulations based on the turbulent modeling in porous media. The effects of both the diameter and the thickness of the spherical shell windscreen on the wind noise reduction performance are investigatedfor both uniform and turbulent incoming flows. It is found that the wind noise at the microphone can be reduced by spherical shell windscreens only when the thickness of the spherical shell windscreen is smaller than 0.1 cmfor uniformincoming flow, and the wind noise reduction increases with the diameter but approaches a constant when the windscreen is largerthan 20 cm.Forturbulentincoming flow, the wind noise reduction performance of the spherical shell windscreen increases with the diameter and reaches the best when the shell thickness is around 1.0 cm.
Zheng, L, Zhu, J, Wang, G, Dah-Chuan Lu, D, McLean, P & He, T 1970, 'Model predictive control based balancing strategy for series-connected lithium-ion battery packs', 2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe), 2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe), IEEE, Warsaw, Poland.
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© assigned jointly to the European Power Electronics and Drives Association & the Institute of Electrical and Electronics Engineers (IEEE). For reducing the inconsistent state of charges (SOCs) of lithium-ion battery cells and making the full use of battery packs, effective battery balancing technology should be in place for battery management systems. Since aged battery packs usually suffer from not only non-uniform cell SOCs and voltages but also non-uniform cell capacities, it is more challenging to balance an aged battery pack than a new one. This paper proposes a model predictive control (MPC) based balancing strategy to fully charge battery packs under such inconsistent conditions, especially for aged battery packs. The algorithm of the proposed strategy for computing the required average balancing current and the predicted balancing current for each cell is presented, followed by employing a minimum cost function value between these two currents to control the operation model of the equalizer for each cell. The simulation results verify the effectiveness of the proposed approach. Compared with the conventional average SOC strategy, the proposed MPC based strategy can effectively avoid over-equalization during the balancing process, thus reducing balancing energy consumption.
Zheng, L, Zhu, J, Wang, G, Lu, DD-C, McLean, P & He, T 1970, 'Experimental analysis and modeling of temperature dependence of lithium-ion battery direct current resistance for power capability prediction', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, Australia, pp. 1-4.
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© 2017 IEEE. Accurate lithium-ion battery power capability prediction gives an indication for managing power flows in or out of batteries within the safe operating area, which is one of the primary challenging functions of battery management systems (BMSs). The battery direct current resistance (DCR) is typically employed for power capability prediction, but its characteristic depends significantly on the ambient temperature. It is essential to investigate systematically the temperature dependence of battery DCR for achieving reliable power capability prediction. Based on a large amount of battery test data, a battery DCR model is proposed for quantitatively describing its temperature dependence. This model is then applied for battery power capability prediction, and the results are verified by experimental results.
Zhenpo, W, Jianyang, W, Jingna, Z, Li, L & Lei, Z 1970, 'Direct yaw-moment control of a FWIA EV based on sliding model control and torque allocation optimization', IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, IECON 2017 - 43rd Annual Conference of the IEEE Industrial Electronics Society, IEEE, Beijing, China, pp. 4615-4620.
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© 2017 IEEE. In this paper, a direct yaw-moment control (DYC) scheme is proposed for a four-wheel-independently-actuated electric vehicle (FWIA EV). An upper controller is based on a reference model with two degrees of freedom (2-DOF) that generates the desired yaw rate for a sliding mode controller to track so as to improve the vehicle dynamic stability. A torque optimization distribution strategy is designed in the lower controller to allocate the required torques to each in-wheel motor for vehicle stability enhancement. The proposed DYC scheme is implemented in a Carmaker vehicle model and a MATLAB/Simulink control model and evaluated in simulations of a snake-lane-change and a double-lane-change maneuver. The results show that the side slip angle and tire load rate have been reduced, on average, by 2/3 using the DYC system compared with those without control. The cases with DYC also provide better tracking of the desired trajectory and yaw rate with smaller steering angle than those without control.
Zhou, Y, Ni, W, Zheng, K, Liu, RP & Yang, Y 1970, 'Node-centric route mutation for large-scale SDN based on 3D earth mover's distance model', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), 2017 17th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Cairns, QLD, Australia, pp. 1-6.
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© 2017 IEEE. Exploiting software-defined networking techniques, randomly and instantly mutating routes can disguise strategically important infrastructure, and protect the integrity of data networks. Route mutation has been to date formulated as NP-complete constraint satisfaction problems where feasible sets of routes need to be generated with exponential computational complexities, limiting algorithmic scalability to large-scale networks. In this paper, we propose a novel node-centric route mutation method which interprets route mutation as a signature matching problem. We formulate the route mutation problem as a three-dimensional earth mover's distance (EMD) model and solve it by using a binary branch and bound method. Considering the scalability, we further propose a heuristic method yields significantly lower computational complexities with marginal loss of robustness against eavesdropping. Simulation results show that our proposed methods can effectively disguise key infrastructure by reducing the difference of historically accumulative traffic among different switches. With significantly reduced complexities, our algorithms are of particular interest to safeguard large-scale networks.
Zhou, Z, Sun, X, Chen, L, Yang, Z, Han, S, Li, K, Zhu, J & Guo, Y 1970, 'A segmented rotor type switched reluctance machine for BSGs of hybrid electric vehicles: Concept, design and analysis', 2017 20th International Conference on Electrical Machines and Systems (ICEMS), 2017 20th International Conference on Electrical Machines and Systems (ICEMS), IEEE, Sydney, NSW, Australia, pp. 1-4.
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© 2017 IEEE. This paper proposes a novel 16/10 segmented rotor switched reluctance machine (SSRM) for belt-driven starter generators (BSGs) of hybrid electric vehicles. The stator of proposed SSRM consists of two types of stator poles: exciting pole and auxiliary pole, and the rotor of proposed SSRM is made up of a series of discrete segments. Firstly, the concept of the conventional SRM and proposed machine is presented. Secondly, the design rules of proposed SSRM are described. Finally, the finite element method (FEM) is employed to get the static characteristics of the proposed SSRM, including the magnetic flux distribution, magnetic flux density, inductance characteristic, torque characteristic and continuous torque. Result shows that the torque ripple of proposed SSRM is low.
Zhu, HL, Ding, C, Wei, G & Guo, YJ 1970, 'A novel base station antenna based on rectangular waveguide', ISAP 2016 - International Symposium on Antennas and Propagation, International Symposium on Antennas and Propagation (ISAP), IEEE, Okinawa, Japan, pp. 196-197.
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A novel base station antenna element is proposed. It consists of a surface of parallel strips to rotate the polarization direction and a segment of a rectangular waveguide. The surface is designed on a single-sided substrate, which has the same area as the aperture of the waveguide. In assembling, the non-copper side of the substrate is placed in direct contact with the aperture of the waveguide antenna. To achieve the polarization rotation, the parallel strips on the surface are rotated by 45° with respect to the walls of the waveguide antenna. By adding the surface, the linear polarization direction of the rectangular waveguide antenna is rotated by 45° to comply with the requirements of cellular industry. SMA connector with a conical probe is used as the coaxial-to-waveguide adaptor. Results have shown that the proposed antenna has a fractional impedance bandwidth of 35%, and a stable radiation pattern is also achieved.
Zhu, JG, Lei, G, Guo, YG, Wang, TS & Ma, B 1970, 'A robust design optimization method for manufacturing SMC-PMSMs and drive systems of six sigma quality', 2017 7th International Conference on Power Electronics Systems and Applications - Smart Mobility, Power Transfer & Security (PESA), 2017 7th International Conference on Power Electronics Systems and Applications - Smart Mobility, Power Transfer & Security (PESA), IEEE, Hong Kong, China, pp. 1-7.
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© 2017 IEEE. The soft magnetic composite (SMC) material has attracted great research interests because of its unique feature of high speed low cost manufacturing of electrical machines of complex 3D flux topologies by the highly cost effective powder metallurgical technology. Some electrical machine manufacturers have recently started producing permanent magnet synchronous motors (PMSMs) with SMC cores. Because of the material diversity and fabrication uncertainties, an aggressively optimized design obtained by the traditional deterministic method often result in low quality product and/or high failure rates. This paper presents a method of robust design optimization for manufacturing SMC-PMSMs and drive systems of six sigma quality. Design examples of a transverse flux SMC-PMSM and drive system are presented.
Zhu, X, Li, L, Zhang, W, Rao, T, Xu, M, Huang, Q & Xu, D 1970, 'Dependency Exploitation: A Unified CNN-RNN Approach for Visual Emotion Recognition', Proceedings of the Twenty-Sixth International Joint Conference on Artificial Intelligence, Twenty-Sixth International Joint Conference on Artificial Intelligence, International Joint Conferences on Artificial Intelligence Organization, Melbourne, Australia, pp. 3595-3601.
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Visual emotion recognition aims to associate images with appropriate emotions. There are different visual stimuli that can affect human emotion from low-level to high-level, such as color, texture, part, object, etc. However, most existing methods treat different levels of features as independent entity without having effective method for feature fusion. In this paper, we propose a unified CNN-RNN model to predict the emotion based on the fused features from different levels by exploiting the dependency among them. Our proposed architecture leverages convolutional neural network (CNN) with multiple layers to extract different levels of features with in a multi-task learning framework, in which two related loss functions are introduced to learn the feature representation. Considering the dependencies within the low-level and high-level features, a new bidirectional recurrent neural network (RNN) is proposed to integrate the learned features from different layers in the CNN model. Extensive experiments on both Internet images and art photo datasets demonstrate that our method outperforms the state-of-the-art methods with at least 7% performance improvement.
Zuo, Y, Wu, Q, Zhang, J & An, P 1970, 'Minimum spanning forest with embedded edge inconsistency measurement for color-guided depth map upsampling', 2017 IEEE International Conference on Multimedia and Expo (ICME), 2017 IEEE International Conference on Multimedia and Expo (ICME), IEEE, Hong Kong, China, pp. 211-216.
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© 2017 IEEE. Color-guided depth map up-sampling, such as Markov-Random-Field-based (MRF-based) methods, is a popular depth map enhancement solution, which normally assumes edge consistency between color image and corresponding depth map. It calculates the coefficients of smoothness term in MRF according to such assumption. However, such consistency is not always true which leads to texture-copying artifacts and blurring depth edges. In this paper, we propose a novel coefficient computing scheme for smoothness term in MRF which is based on the distance between pixels in the Minimum Spanning Trees (Forest) to better preserve depth edges. The explicit edge inconsistency measurement is embedded into weights of edges in Minimum Spanning Trees, which significantly mitigates texture-copying artifacts. The proposed method is evaluated on Middlebury datasets and ToF-Mark datasets which demonstrates improved results compared with state-of-the-art methods.