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. 1792-1795.
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Anh, TL, Le, CT & 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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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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© EDP Sciences, SMAI. 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.
Arslanagic, S & Ziolkowski, RW 2017, 'Cylindrical and Spherical Active Coated Nanoparticles as Nanoantennas: Active nanoparticles as nanoantennas.', IEEE Antennas and Propagation Magazine, vol. 59, no. 6, pp. 14-29.
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In this article, we review the fundamental properties of several spherical and cylindrical, passive, and active coated nanoparticles (CNPs) with an emphasis on their potential for nanoantenna and nanoamplifier synthesis. For the spherical geometries, the nanoparticles are excited by an electric Hertzian dipole (EHD), which represents, e.g., a stimulated atom or molecule. The cyl indr ical nanoparticles are excited by a magnetic line source (MLS). In the active cases, gain is added to the core region of the particle. For simplicity, it is represented by a canonical, frequency-independent gain model. We demonstrate that specific CNPs can be designed to be resonant and well matched to their respective excitation sources. With active cores, these designs can lead to extremely large total radiated powers. For both configurations, insights into the effects of the nanoparticle material composition, source location, and orientation will be given on the basis of studying their near-field and power-flow density distributions, total radiated powers, and directivity properties.
Arslanagic, S & Ziolkowski, RW 2017, 'New Frontiers in Passive and Active Nanoantennas', IEEE Antennas and Propagation Magazine, vol. 59, no. 6, pp. 8-+.
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The articles included in this special section focus on several recent advances in the field of passive and active nanoantennas that employ not only traditional based realizations but also their new frontiers.
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.
Baum, TC, Ziolkowski, RW, Ghorbani, K & Nicholson, KJ 2017, 'Investigations of a Load-Bearing Composite Electrically Small Egyptian Axe Dipole Antenna', IEEE Transactions on Antennas and Propagation, vol. 65, no. 8, pp. 3827-3837.
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© 1963-2012 IEEE. An electrically small, metamaterial-inspired Egyptian axe dipole (EAD) antenna has been investigated for use in structural composite materials. The EAD antenna consists of a differentially fed dipole element integrated with a near-field resonant parasitic EAD element. These elements have been adapted to these materials resulting in a system that is impedance matched and radiates efficiently at 307 MHz. Three cases have been identified and investigated to ascertain the performance of the manufacturing techniques and material properties used to build these electrically small antennas, as well as their performance characteristics. Uniquely, an embroidered conductive thread and a new carbon fiber based, nonwoven mat have been investigated for use as the conducting elements. Both cases are compared with a copper variant of the EAD antenna. All three prototypes were tested. Measurements confirm that both the nonwoven mat and the embroidered versions of the EAD antennas perform similarly with maximum realized gains ranging from 1.72 to 1.90 dBi.
Beydoun, G, Hoffmann, A & Gill, A 2017, 'Constructing enhanced default theories incrementally', Complex and Intelligent Systems, vol. 3, no. 2, pp. 83-92.
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The main difference between various formalisms of non-monotonic reasoning is the representation of non-monotonic rules. In default logic, they are represented by special expressions called defaults. In default logic, commonsense knowledge about the world is represented as a set of named defaults. The use of defaults is popular because they reduce the complexity of the representation, and they are sufficient for knowledge representation in many naturally occurring contexts. This paper offers an incremental process to acquire defaults from human experts directly and at the same time it provides added semantics to defaults by adding priorities to defaults and creating additional relations between them. The paper uses an existing incremental framework, NRDR, to generate these defaults. This framework is chosen as it not only enables incremental context driven formulation of defaults, but also allows experts to introduce their own domain terms. In choosing this framework, the paper broadens its utility.
Bozejko, 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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© 2017 Archives of Control Sciences 2017. The 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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Chen, SL, Qin, PY, Ding, C & Guo, YJ 2017, 'Cavity-backed proximity-coupled reconfigurable microstrip antenna with agile polarizations and steerable beams', IEEE Transactions on Antennas and Propagation.
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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 cavitybacked proximity-coupled reconfigurable microstrip antenna proposed in this communication provides an efficient solution. Beam lead PIN diodes DSM8100-000 are employed as switching elements to achieve the reconfiguration. Three different linear polarizations (0 & #x00B0;, 45 & #x00B0;, 90 & #x00B0;) 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 parasiticelement network is printed on the same plane of the radiating patch, thereby making the antenna compact. This antenna has 9 different working modes and for all the working modes, the reflection coefficients are below & #x2212;10 dB with the measured realized gains ranging from 7.2-8.1 dBi.
Chen, SL, Qin, PY, 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, SL, Wei, F, Qin, PY, Jay Guo, Y & 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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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 atφ=0°,φ=45°,φ=90°,orφ=135°canberealized.Thesize 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 |S11| ≤ -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, Du, H, Zhang, J, Luo, G, Que, X, Zhang, N, Bian, Z, Guo, Y, Li, L, Chen, Z & Wu, X 2017, 'Erratum: Adiposity and blood pressure among 55 000 relatively lean rural adults in southwest of China (Journal of human hypertension (2015) 29 9 (522-529))', Journal of human hypertension, vol. 31, no. 7, p. 485.
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This corrects the article DOI: 10.1038/jhh.2014.129.
Chen, X, Qin, PY, 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.
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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.
Chenhu, G, Geng, J, Zhou, H, Li, J, Liu, L, Liang, X, Zhu, W, Jin, R & Ziolkowski, RW 2017, 'Truncated Circular Cone Slot Antenna Array That Radiates a Circularly Polarized Conical Beam', IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS, vol. 16, pp. 2574-2577.
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Cooper, C, Franklin, D, Ros, M, Safaei, F & Abolhasan, M 2017, 'A Comparative Survey of VANET Clustering Techniques', IEEE Communications Surveys 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.
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.
Ding, C, Jones, B, Guo, YJ & Qin, PY 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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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 |S11| 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.
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.
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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.
Dutkiewicz, E, Costa-Perez, X, Kovács, IZ & Mueck, M 2017, 'Massive Machine-Type Communications', IEEE Network, vol. 31, no. 6, pp. 6-7.
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The articles in this special section address the techology and applications supported by machine-type communications (MTC). Here, MTC is characterized by fully automatic data generation, exchange, processing, and actuation among intelligent machines, without or with low intervention of humans. With the rapid penetration of embedded devices, MTC is becoming the dominant communication paradigm for a wide range of emerging smart services including healthcare, manufacturing, utilities, consumer goods, and transportation. Industry analysts predict that 50 billion devices will be connected to mobile networks worldwide by 2020. While mobile phone devices communicating among humans will still exist, machine-type devices sending bits of information to other machines, servers, clouds, or humans will account for a much larger proportion and thus create what is referred to as massive MTC (MMTC).
Dutra, G, Canning, J, Padden, W, Martelli, C & Dligatch, S 2017, 'Large area optical mapping of surface contact angle', Optics Express, vol. 25, no. 18, pp. 21127-21144.
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© 2017 Optical Society of America. Top-down contact angle measurements have been validated and confirmed to be as good if not more reliable than side-based measurements. A range of samples, including industrially relevant materials for roofing and printing, has been compared. Using the top-down approach, mapping in both 1-D and 2-D has been demonstrated. The method was applied to study the change in contact angle as a function of change in silver (Ag) nanoparticle size controlled by thermal evaporation. Large area mapping reveals good uniformity for commercial Aspen paper coated with black laser printer ink. A demonstration of the forensic and chemical analysis potential in 2-D is shown by uncovering the hidden CsF initials made with mineral oil on the coated Aspen paper. The method promises to revolutionize nanoscale characterization and industrial monitoring as well as chemical analyses by allowing rapid contact angle measurements over large areas or large numbers of samples in ways and times that have not been possible before.
Edwards, D, Cheng, M, Wong, A, Zhang, J & Wu, Q 2017, 'Ambassadors of Knowledge Sharing: Co-produced Travel Information Through Tourist-Local Social Media Exchange', International Journal of Contemporary Hospitality Management, vol. 29, no. 2, pp. 690-708.
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Purpose: The aim of this study is to understand the knowledge sharing structure and co-production of trip-related knowledge through online travel forums.
Design/methodology/approach: The travel forum threads were collected from TripAdvisor 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.
Findings: Findings indicate that the knowledge structure is created by community residents who camouflage as local experts, 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 implications: The 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/value: This 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.
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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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.
Fonseka, HA, Ameruddin, AS, Caroff, P, Tedeschi, D, De Luca, M, Mura, F, Guo, Y, Lysevych, M, Wang, F, Tan, HH, Polimeni, A & Jagadish, C 2017, 'InP-InxGa1-xAs core-multi-shell nanowire quantum wells with tunable emission in the 1.3-1.55 μm wavelength range', Nanoscale, vol. 9, no. 36, pp. 13554-13562.
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© 2017 The Royal Society of Chemistry. The usability and tunability of the essential InP-InGaAs material combination in nanowire-based quantum wells (QWs) are assessed. The wurtzite phase core-multi-shell InP-InGaAs-InP nanowire QWs are characterised using cross-section transmission electron microscopy and photoluminescence measurements. The InP-InGaAs direct interface is found to be sharp while the InGaAs-InP inverted interface is more diffused, in agreement with their planar counterpart. Bright emission is observed from the single nanowires containing the QWs at room temperature, with no emission from the InP core or outer barrier. The tunability of the QW emission wavelength in the 1.3-1.55 μm communication wavelength range is demonstrated by varying the QW thickness and in the 1.3 μm range by varying the composition. The experiments are supported by simulation of the emission wavelength of the wurtzite phase InP-InGaAs QWs in the thickness range considered. The radial heterostructure is further extended to design multiple QWs with bright emission, therefore establishing the capability of this material system for nanowire based optical devices for communication applications.
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.
Gao, X, Du, J, Zhang, T & Guo, YJ 2017, 'Noise and conversion performance of a high- Tcsuperconducting Josephson junction mixer at 0.6 THz', Applied Physics Letters, vol. 111, no. 19, pp. 1-5.
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© 2017 AU-Crown. This letter presents both theoretical and experimental investigations on the noise and conversion performance of a high-T c 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-T c superconducting Josephson-junction mixer: electromagnetic design, analysis and characterization', Superconductor Science and Technology, vol. 30, no. 9, pp. 1-9.
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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.
Ge, XJ, Livesey, P, Wang, J, Huang, SD, He, X & Zhang, CQ 2017, 'Deconstruction waste management through 3D reconstruction and BIM: a case study', Visualization in Engineering, vol. 5, no. 1.
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The construction industry is responsible for 50% of the solid waste generated worldwide. Governments around the
world formulate legislation and regulations concerning recycling and re-using building materials, aiming to reduce
waste and environmental impact. Researchers have also been developing strategies and models of waste management
for construction and demolition of buildings. The application of Building Information Modeling (BIM) is an example of
this. BIM is emergent technology commonly used to maximize the efficiency of design, construction and maintenance
throughout the entire lifecycle. The uses of BIM on deconstruction or demolition are not common; especially the fixtures
and fittings of buildings are not considered in BIM models. The development of BIM is based on two-dimensional
drawings or sketches, which may not be accurately converted to 3D BIM models. In addition, previous researches mainly
focused on construction waste management. There are few studies about the deconstruction waste management
focusing on demolition. To fill this gap, this paper aims to develop a framework using a reconstructed 3D model with
BIM, for the purpose of improving BIM accuracy and thus developing a deconstruction waste management system to
improve demolition efficiency, effective recycling and cost savings. In particular, the developed as-built BIM will be used
to identify and measure recyclable materials, as well as to develop a plan for the recycling process.
Gill, AQ, Braytee, A & Hussain, FK 2017, 'Adaptive service e-contract information management reference architecture', VINE Journal of Information and Knowledge Management Systems, vol. 47, no. 3, pp. 395-410.
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© 2017, © Emerald Publishing Limited. Purpose: The aim of this paper is to report on the adaptive e-contract information management reference architecture using the systematic literature review (SLR) method. Enterprises need to effectively design and implement complex adaptive e-contract information management architecture to support dynamic service interactions or transactions. Design/methodology/approach: The SLR method is three-fold and was adopted as follows. First, a customized literature search with relevant selection criteria was developed, which was then applied to initially identify a set of 1,573 papers. Second, 55 of 1,573 papers were selected for review based on the initial review of each identified paper title and abstract. Finally, based on the second review, 24 papers relevant to this research were selected and reviewed in detail. Findings: This detailed review resulted in the adaptive e-contract information management reference architecture elements including structure, life cycle and supporting technology. Research limitations/implications: The reference architecture elements could serve as a taxonomy for researchers and practitioners to develop context-specific service e-contract information management architecture to support dynamic service interactions for value co-creation. The results are limited to the number of selected databases and papers reviewed in this study. Originality/value: This paper offers a review of the body of knowledge and novel e-contract information management reference architecture, which is important to support the emerging trends of internet of services.
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.
Guo, ZC, Wong, SW, Lin, JY, Zhu, L, Chu, QX, Zhang, Q & Yang, Y 2017, 'Triple-Mode Cavity Bandpass Filter on Doublet with Controllable Transmission Zeros', IEEE Access, vol. 5, pp. 6969-6977.
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© 2013 IEEE. On the basis of doublet and its properties, a class of multiple-mode narrow band bandpasss filter is designed and fabricated by simultaneously exploiting the three resonant modes in a single rectangular cavity: TE 101 , TE 011 , and TM 110 modes. The input/output ports of the proposed filter are fed by coupling a microstrip line to a slot on the side wall of a rectangular cavity. Different modes are excited by changing the position and shape of the two slots at input and output of the rectangular cavity without any intra-cavity coupling. Besides three poles within the passband, a pair of transmission zeros (TZs) is achieved, which can be controlled independently by setting the positions of the two TZs at the lower and/or upper stopband. High stopband attenuation and high filtering selectivity are achieved by considerably allocating three transmission poles and two zeros. In order to verify the proposed theory, two filter prototypes are fabricated and measured.
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, Niyato, D, Wang, P, Kim, DI & Le, LB 2017, 'Optimal Data Scheduling and Admission Control for Backscatter Sensor Networks', IEEE Transactions on Communications, vol. 65, no. 5, pp. 2062-2077.
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© 2017 IEEE. This paper studies the data scheduling and admission control problem for a backscatter sensor network (BSN). In the network, instead of initiating their own transmissions, the sensors can send their data to the gateway just by switching their antenna impedance and reflecting the received RF signals. As such, we can reduce remarkably the complexity, the power consumption, and the implementation cost of sensor nodes. Different sensors may have different functions, and data collected from each sensor may also have a different status, e.g., urgent or normal, and thus we need to take these factors into account. Therefore, in this paper, we first introduce a system model together with a mechanism in order to address the data collection and scheduling problem in the BSN. We then propose an optimization solution using the Markov decision process framework and a reinforcement learning algorithm based on the linear function approximation method, with the aim of finding the optimal data collection policy for the gateway. Through simulation results, we not only show the efficiency of the proposed solution compared with other baseline policies, but also present the analysis for data admission control policy under different classes of sensors as well as different types of data.
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, vol. 5, pp. 732-754.
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© 2013 IEEE. In addition to being environment friendly, vehicle-to-grid (V2G) systems can help the plug-in electric vehicle (PEV) users in reducing their energy costs and 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 of charging/discharging stations, current load, and supply of the power grid) to achieve the best charging and discharging performance, data communication plays a crucial role. However, since the PEV users are highly mobile, information from V2G systems is not always available for many reasons, e.g., wireless link failures and cyber attacks. Therefore, in this paper, we introduce a novel concept using cyber insurance to 'transfer' cyber risks, e.g., unavailable information, 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 PEV user is always guaranteed the best price for charging/discharging. In particular, we formulate the optimal energy cost problem for the PEV user by adopting a Markov decision process framework. We then propose a learning algorithm to help the PEV user make optimal decisions, e.g., to charge or discharge and to buy or not to buy insurance, in an online fashion. Through simulations, we show that cyber insurance is an efficient solution not only in dealing with cyber risks, but also in maximizing revenue for the PEV user.
Hossain, MA, Canning, J, Yu, Z, Ast, S, Rutledge, PJ, Wong, JK-H, Jamalipour, A & Crossley, MJ 2017, 'Time-resolved and temperature tuneable measurements of fluorescent intensity using a smartphone fluorimeter', ANALYST, vol. 142, no. 11, pp. 1953-1961.
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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 & 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, XS 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 & Jay Guo, Y 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, X, Zhang, J, Fan, L, Wu, Q & Yuan, C 2017, 'A Systematic Approach for Cross-Source Point Cloud Registration by Preserving Macro and Micro Structures.', IEEE transactions on image processing : a publication of the IEEE Signal Processing Society, vol. 26, no. 7, pp. 3261-3276.
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We propose a systematic approach for registering cross-source point clouds that come from different kinds of sensors. This task is especially challenging due to the presence of significant missing data, large variations in point density, scale difference, large proportion of noise, and outliers. The robustness of the method is attributed to the extraction of macro and micro structures. Macro structure is the overall structure that maintains similar geometric layout in cross-source point clouds. Micro structure is the element (e.g., local segment) being used to build the macro structure. We use graph to organize these structures and convert the registration into graph matching. With a novel proposed descriptor, we conduct the graph matching in a discriminative feature space. The graph matching problem is solved by an improved graph matching solution, which considers global geometrical constraints. Robust cross source registration results are obtained by incorporating graph matching outcome with RANSAC and ICP refinements. Compared with eight state-of-the-art registration algorithms, the proposed method invariably outperforms on Pisa Cathedral and other challenging cases. In order to compare quantitatively, we propose two challenging cross-source data sets and conduct comparative experiments on more than 27 cases, and the results show we obtain much better performance than other methods. The proposed method also shows high accuracy in same-source data sets.
Hussein, F & Piccardi, M 2017, 'V-JAUNE: A framework for joint action recognition and video summarization', ACM Transactions on Multimedia Computing, Communications and Applications, vol. 13, no. 2.
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© 2017 ACM. 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.
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.
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Wireless 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 Unanue, I, Zare Borzeshi & 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. 102-102.
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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.
Kamiński, PM, Ziolkowski, RW & Arslanagić, S 2017, 'Riemann–Hilbert technique scattering analysis of metamaterial-based asymmetric 2D open resonators', EPJ Applied Metamaterials, vol. 4, pp. 1-14.
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The scattering properties of metamaterial-based asymmetric two-dimensional open resonators excited by an electric line source are investigated analytically. The resonators are, in general, composed of two infinite and concentric cylindrical layers covered with an infinitely thin, perfect conducting shell that has an infinite axial aperture. The line source is oriented parallel to the cylinder axis. An exact analytical solution of this problem is derived. It is based on the dual-series approach and its transformation to the equivalent Riemann–Hilbert problem. Asymmetric metamaterial-based configurations are found to lead simultaneously to large enhancements of the radiated power and to highly steerable Huygens-like directivity patterns; properties not attainable with the corresponding structurally symmetric resonators. The presented open resonator designs are thus interesting candidates for many scientific and engineering applications where enhanced directional near- and far-field responses, tailored with beam shaping and steering capabilities, are highly desired.
Karmokar, DK, Guo, YJ, Qin, PY, 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.
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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IEEE This paper considers how to allocate the bandwidth to multiple radio access technologies (RATs) in heterogeneous networks (HetNets). 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 signal-to-interference ratio (SIR) 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.
Kumar, J, Prakash, O, Mahakud, R, Agrawal, SK, Dixit, SK, Nakhe, SV & Canning, J 2017, 'Wavelength independent chemical sensing using etched thermally regenerated FBG', Sensors and Actuators B: Chemical, vol. 244, pp. 54-60.
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© 2016 Elsevier B.V. This paper presents the first time studies on chemical sensing characteristics of HF etched thermally regenerated fiber Bragg grating (FBG). No shift in Bragg wavelength, λ B ragg , of the FBG during HF etching has been observed for thermally regenerated FBGs. This contrasts with etching of conventional Type-I gratings both with and without annealing at temperatures, T ∼ 600 °C for which the regeneration does not occur. These HF etched FBGs are studied for refractive index sensing of four media i.e. air, methanol, ethanol and ethylene glycol for the chemical sensing applications. The regenerated grating has a variation in reflection intensity with little shift in λ B ragg , i.e. Δλ B ragg < 5 pm. For the non-annealed FBG, both reflected power and peak position of FBGs changed with change in refractive index creating a dual parameter problem for sensing. In this case, the wavelength shifted by more than two orders of magnitude i.e. Δλ B ragg > 1 nm. For the annealed FBGs at 600 °C, the change in reflected power of the FBG was higher than the non-annealed FBGs while Δλ Bragg was comparable. For chemical sensing based on etched regenerated grating, the removal of the wavelength shift from measurements greatly reduces sensor interrogation complexity allowing for simple amplitude based detection schemes.
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, 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, Xu, RYD, 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 TM 310 and TM 130 ) and the second high-order mode (TM 320 ) 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, Qian, J, Zhao, R, Wang, F & Wang, Z 2017, 'Dual-wavelength mode-locked fiber laser based on tungsten disulfide saturable absorber', Laser Physics, vol. 27, no. 12, pp. 1-6.
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© 2017 Astro Ltd. We report on the generation of dual-wavelength mode-locked laser pulse in an Er-doped ring-shaped fiber cavity with WS 2 nanosheets based saturable absorber (SA), emitting at wavelength of 1531.8 nm and 1556.7 nm. The WS 2 nanosheets were precipitated on the head face of fiber patch cord via light precipitation method. By adjusting the polarization of lasing mode, the gain of the Er-doped fiber laser was effectively controlled and the stable dual-wavelength mode-locking operation was achieved. Our investigation revealed WS 2 's extraordinary nonlinear properties, which make it an excellent material for saturable absorber for passively mode-locked fiber lasers.
Lin, W & Wong, H 2017, 'Multi-polarization Reconfigurable Circular Patch Antenna with L-shaped Probes', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 1549-1552.
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Lin, W & Wong, H 2017, 'Wideband Circular Polarization Reconfigurable Antenna with L-shaped Feeding Probes', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 2114-2117.
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Lin, W, Wong, H & Ziolkowski, RW 2017, 'Wideband Pattern-Reconfigurable Antenna with Switchable Broadside and Conical Beams', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 2638-2641.
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© 2017 IEEE. A wideband, pattern-reconfigurable antenna is reported that is, for example, a good candidate for ceiling-mounted indoor wireless systems. Switchable linearly polarized broadside and conical radiation patterns are achieved by systematically integrating a wideband low-profile monopolar patch antenna with a wideband L-probe fed patch antenna. The monopolar patch acts as the ground for the L-probe fed patch, which is fed with a coaxial cable that replaces one shorting via of the monopolar patch to avoid deterioration of the conical-beam pattern. A simple switching feed network facilitates the pattern reconfigurability. A prototype was fabricated and tested. The measured results confirm the predicted wideband radiation performance. The operational impedance bandwidth, i.e., S 11 ≤-10 dB, is obtained as the overlap of the bands associated with both pattern modalities. It is wide, from 2.25 to 2.85 GHz (23.5%). Switchable broadside and conical radiation patterns are observed across this entire operating bandwidth. The peak measured gain was 8.2 dBi for the broadside mode and 6.9 dBi for the conical mode. The overall profile of this antenna is 0.13λ 0 at its lowest operating frequency.
Lin, W, Ziolkowski, RW & Baum, TC 2017, '28GHz Compact Omni-Directional Circularly Polarized Antenna for Device-to-Device (D2D) Communications in Future 5G Systems', IEEE Transactions on Antennas and Propagation, vol. 65, no. 12, pp. 6904-6911.
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IEEE An omni-directional circularly polarized (OCP) antenna operating at 28GHz is reported and has been found to be a promising candidate for Device-to-Device (D2D) communications in the next generation (5G) wireless systems. The OCP radiation is realized by systematically integrating electric and magnetic dipole elements into a compact disc-shaped configuration (9.23 mm & #x00B3; & #x0003D; 0.0076 & #x03BB;30 at 28 GHz) in such a manner that they are oriented in parallel and radiate with the proper phase difference. The entire antenna structure was printed on a single piece of dielectric substrate using standard PCB manufacturing technologies and, hence, is amenable to mass production. A prototype OCP was fabricated on RogersTM 5880 substrate and was tested. The measured results are in good agreement with their simulated values and confirm the reported design concepts. Good OCP radiation patterns were produced with a measured peak realized RHCP gain of 2.2 dBic. The measured OCP overlapped impedance & #x0026; AR bandwidth was 2.2 GHz, from 26.5 to 28.7 GHz, an 8.0 & #x0025; fractional bandwidth, which completely covers the 27.5 to 28.35 GHz band proposed for 5G cellular systems.
Liu, F, Gong, C, Zhou, T, Fu, K, He, XS & Yang, J 2017, 'Visual Tracking via Nonnegative Multiple Coding', IEEE Transactions on Multimedia, vol. 19, no. 12.
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It has been extensively observed that an accurate appearance
model is critical to achieving satisfactory performance
for robust object tracking. Most existing top-ranked methods
rely on linear representation over a single dictionary, which
brings about improper understanding on the target appearance.
To address this problem, in this paper, we propose a novel
appearance model named as “Nonnegative Multiple Coding”
(NMC) to accurately represent a target. First, a series of local
dictionaries are created with different pre-defined numbers of
nearest neighbors, and then the contributions of these dictionaries
are automatically learned. As a result, this ensemble of
dictionaries can comprehensively exploit the appearance information
carried by all the constituted dictionaries. Second, the
existing methods explicitly impose the nonnegative constraint
to coefficient vectors, but in the proposed model, we directly
deploy an efficient `2 norm regularization to achieve the similar
nonnegative purpose with theoretical guarantees. Moreover, an
efficient occlusion detection scheme is designed to alleviate
tracking drifts, and it investigates whether negative templates are
selected to represent the severely occluded target. Experimental
results on two benchmarks demonstrate that our NMC tracker is
able to achieve superior performance to state-of-the-art methods.
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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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 Artifacts 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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Abstract:
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. 1-5.
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Copyright © 2017 John Wiley & Sons, Ltd. How 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 sem antic 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, Y, Lu, Y, Yang, X, Zheng, X, Wen, S, Wang, F, Vidal, X, Zhao, J, Liu, D, Zhou, Z, Ma, C, Zhou, J, Piper, JA, Xi, P & Jin, D 2017, 'Amplified stimulated emission in upconversion nanoparticles for super-resolution nanoscopy', Nature, vol. 543, no. 7644, pp. 229-233.
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Lanthanide-doped glasses and crystals are attractive for laser applications because the metastable energy levels of the trivalent lanthanide ions facilitate the establishment of population inversion and amplified stimulated emission at relatively low pump power1,2,3. At the nanometre scale, lanthanide-doped upconversion nanoparticles (UCNPs) can now be made with precisely controlled phase, dimension and doping level4,5. When excited in the near-infrared, these UCNPs emit stable, bright visible luminescence at a variety of selectable wavelengths6,7,8,9, with single-nanoparticle sensitivity10,11,12,13, which makes them suitable for advanced luminescence microscopy applications. Here we show that UCNPs doped with high concentrations of thulium ions (Tm3+), excited at a wavelength of 980 nanometres, can readily establish a population inversion on their intermediate metastable 3H4 level: the reduced inter-emitter distance at high Tm3+ doping concentration leads to intense cross-relaxation, inducing a photon-avalanche-like effect that rapidly populates the metastable 3H4 level, resulting in population inversion relative to the 3H6 ground level within a single nanoparticle. As a result, illumination by a laser at 808 nanometres, matching the upconversion band of the 3H4 → 3H6 transition, can trigger amplified stimulated emission to discharge the 3H4 intermediate level, so that the upconversion pathway to generate blue luminescence can be optically inhibited. We harness these properties to realize low-power super-resolution stimulated emission depletion (STED) microscopy and achieve nanometre-scale optical resolution (nanoscopy), imaging single UCNPs; the resolution is 28 nanometres, that is, 1/36th of the wavelength. These engineered nanocrystals offer saturation intensity two orders of magnitude lower than those of fluorescent probes currently employed in stimulated emission depletion microscopy, suggesting a new way of alleviating the square-root law that typically li...
Lu, D, Sang, J, Chen, Z, Xu, M & Mei, T 2017, 'Who Are Your "Real" Friends: Analyzing and Distinguishing Between Offline and Online Friendships From Social Multimedia Data', IEEE TRANSACTIONS ON MULTIMEDIA, vol. 19, no. 6, pp. 1299-1313.
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Lu, J, Xuan, J, Zhang, G, Xu, YD & 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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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.
Luong, NC, Hoang, DT, Wang, P, Niyato, D & Han, Z 2017, 'Applications of Economic and Pricing Models for Wireless Network Security: A Survey', Communications Surveys and Tutorials, IEEE Communications Society, 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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Ma, C, Xu, X, Wang, F, Zhou, Z, Liu, D, Zhao, J, Guan, M, Lang, CI & Jin, D 2017, 'Optimal Sensitizer Concentration in Single Upconversion Nanocrystals.', Nano Letters, vol. 17, no. 5, pp. 2858-2864.
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Each single upconversion nanocrystal (UCNC) usually contains thousands of photon sensitizers and hundreds of photon activators to up-convert near-infrared photons into visible and ultraviolet emissions. Though in principle further increasing the sensitizers' concentration will enhance the absorption efficiency to produce brighter nanocrystals, typically 20% of Yb3+ ions has been used to avoid the so-called "concentration quenching" effect. Here we report that the concentration quenching effect does not limit the sensitizer concentration and NaYbF4 is the most bright host matrix. Surface quenching and the large size of NaYbF4 nanocrystals are the only factors limiting this optimal concentration. Therefore, we further designed sandwich nanostructures of NaYbF4 between a small template core to allow an epitaxial growth of the size-tunable NaYbF4 shell enclosed by an inert shell to minimize surface quenching. As a result, the suspension containing 25.2 nm sandwich structure UCNCs is 1.85 times brighter than the homogeneously doped ones, and the brightness of each single 25.2 nm heterogeneous UCNC is enhanced by nearly 3 times compared to the NaYF4: 20% Yb3+, 4% Tm3+ UCNCs in similar sizes. Particularly, the blue emission intensities of the UCNCs with the sandwich structure in the size of 13.6 and 25.2 nm are 1.36 times and 3.78 times higher than that of the monolithic UCNCs in the similar sizes. Maximizing the sensitizer concentration will accelerate the development of brighter and smaller UCNCs as more efficient biomolecule probes or photon energy converters.
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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Niazi, M, Mahmood, S, Alshayeb, M, Baqais, AAB & Gill, AQ 2017, 'Motivators for adopting social computing in global software development: An empirical study', Journal of Software: Evolution and Process, vol. 29, no. 8.
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Copyright © 2017 John Wiley & Sons, Ltd. Managing communication in collaborative global software development (GSD) projects is both critical and challenging. While social computing has received much attention from practitioners, social computing adoption is still an emerging research area in GSD. This research paper provides a review of the academic research in social computing and identifies motivators for adopting social computing in the GSD context. We applied the systematic literature review (SLR) and questionnaire survey with 35 software industry experts to address the research objective. Firstly, we implemented a formal SLR approach and identified an initial set of social computing adoption motivators. Secondly, a questionnaire survey was developed based on the SLR and was tested by means of a pilot study. The findings of this combined SLR and questionnaire survey indicate that real-time communication and coordination, knowledge acquisition, expert feedback, and information sharing are the key factors that motivate social computing adoption in GSD projects. The results of t test (ie, t =.558, P =.589) show that there is no significant difference between the findings of SLR and questionnaire. The results of this study suggest the need for developing social computing strategies and policies to guide the strategic adoption of social computing tools in GSD projects.
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.
Pei, J, Yang, J, Wang, X, Wang, F, Mokkapati, S, Lü, T, Zheng, JC, Qin, Q, Neshev, D, Tan, HH, Jagadish, C & Lu, Y 2017, 'Excited State Biexcitons in Atomically Thin MoSe2', ACS Nano, vol. 11, no. 7, pp. 7468-7475.
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© 2017 American Chemical Society. The tightly bound biexcitons found in atomically thin semiconductors have very promising applications for optoelectronic and quantum devices. However, there is a discrepancy between theory and experiment regarding the fundamental structure of these biexcitons. Therefore, the exploration of a biexciton formation mechanism by further experiments is of great importance. Here, we successfully triggered the emission of biexcitons in atomically thin MoSe 2 , via the engineering of three critical parameters: dielectric screening, density of trions, and excitation power. The observed binding energy and formation dynamics of these biexcitons strongly support the model that the biexciton consists of a charge attached to a trion (excited state biexciton) instead of four spatially symmetric particles (ground state biexciton). More importantly, we found that the excited state biexcitons not only can exist at cryogenic temperatures but also can be triggered at room temperature in a freestanding bilayer MoSe 2 . The demonstrated capability of biexciton engineering in atomically thin MoSe 2 provides a route for exploring fundamental many-body interactions and enabling device applications, such as bright entangled photon sources operating at room temperature.
Peng, K, Parkinson, P, Gao, Q, Boland, JL, Li, Z, Wang, F, Mokkapati, S, Fu, L, Johnston, MB, Tan, HH & Jagadish, C 2017, 'Single n+-i-n+ InP nanowires for highly sensitive terahertz detection', Nanotechnology, vol. 28, no. 12, pp. 1-10.
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© 2017 IOP Publishing Ltd. Developing single-nanowire terahertz (THz) electronics and employing them as sub-wavelength components for highly-integrated THz time-domain spectroscopy (THz-TDS) applications is a promising approach to achieve future low-cost, highly integrable and high-resolution THz tools, which are desirable in many areas spanning from security, industry, environmental monitoring and medical diagnostics to fundamental science. In this work, we present the design and growth of n + -i-n + InP nanowires. The axial doping profile of the n + -i-n + InP nanowires has been calibrated and characterized using combined optical and electrical approaches to achieve nanowire devices with low contact resistances, on which the highly-sensitive InP single-nanowire photoconductive THz detectors have been demonstrated. While the n + -i-n + InP nanowire detector has a only pA-level response current, it has a 2.5 times improved signal-to-noise ratio compared with the undoped InP nanowire detector and is comparable to traditional bulk THz detectors. This performance indicates a promising path to nanowire-based THz electronics for future commercial applications.
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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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).
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.
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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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.
Siyari, P, Krunz, M & Nguyen, DN 2017, 'Friendly Jamming in a MIMO Wiretap Interference Network: A Nonconvex Game Approach', IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, vol. 35, no. 3, pp. 601-614.
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© 1983-2012 IEEE. We consider joint optimization of artificial noise (AN) and information signals in a MIMO wiretap interference network, wherein the transmission of each link may be overheard by several MIMO-capable eavesdroppers. Each information signal is accompanied with AN, generated by the same user to confuse nearby eavesdroppers. Using a noncooperative game, a distributed optimization mechanism is proposed to maximize the secrecy rate of each link. The decision variables here are the covariance matrices for the information signals and ANs. However, the nonconvexity of each link's optimization problem (i.e., best response) makes conventional convex games inapplicable, even to find whether a Nash equilibrium (NE) exists. To tackle this issue, we analyze the proposed game using a relaxed equilibrium concept, called quasi-NE (QNE). Under a constraint qualification condition for each player's problem, the set of QNEs includes the NE of the proposed game. We also derive the conditions for the existence and uniqueness of the resulting QNE. It turns out that the uniqueness conditions are too restrictive, and do not always hold in typical network scenarios. Thus, the proposed game often has multiple QNEs, and convergence to a QNE is not always guaranteed. To overcome these issues, we modify the utility functions of the players by adding several specific terms to each utility function. The modified game converges to a QNE even when multiple QNEs exist. Furthermore, players have the ability to select a desired QNE that optimizes a given social objective (e.g., sum rate or secrecy sum rate). Depending on the chosen objective, the amount of signaling overhead as well as the performance of resulting QNE can be controlled. Simulations show that not only can we guarantee the convergence to a QNE, but also due to the QNE selection mechanism, we can achieve a significant improvement in terms of secrecy sum rate and power efficiency, especially in dense networks.
Sun, B, Guo, Y, Fang, G & Dutkiewicz, E 2017, 'An efficient dictionary refinement algorithm for multiple target counting and localization in wireless sensor networks', International Journal of Distributed Sensor Networks, vol. 13, no. 8.
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© The Author(s) 2017. Many applications provided by wireless sensor networks rely heavily on the location information of the monitored targets. Since the number of targets in the region of interest is limited, localization benefits from compressive sensing, sampling number can be greatly reduced. Despite many compressive sensing–based localization methods proposed, existing solutions are based on the assumption that all targets fall on a sampled and fixed grid, performing poorly when there are targets deviating from the grid. To address such a problem, in this article, we propose a dictionary refinement algorithm where the grid is iteratively adjusted to alleviate the deviation. In each iteration, the representation coefficient and the grid parameters are updated in turn. After several iterations, the measurements can be sparsely represented by the representation coefficient which indicates the number and locations of multiple targets. Extensive simulation results show that the proposed dictionary refinement algorithm achieves more accurate counting and localization compared to the state-of-the-art compressive sensing reconstruction algorithms.
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 & Jay Guo, Y 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%.
Ta, SX, Lee, K, Park, I & Ziolkowski, RW 2017, 'Compact Crossed-Dipole Antennas Loaded with Near-Field Resonant Parasitic Elements', IEEE Transactions on Antennas and Propagation, vol. 65, no. 2, pp. 482-488.
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© 2016 IEEE.Two compact planar crossed-dipole antennas loaded with near-field resonant parasitic (NFRP) elements are reported. The NFRP and crossed-dipole elements are designed for the desired circularly polarized (CP) radiation. By placing the NFRP element over the driven element at angles of 0° and 45°, respectively, dual-band and broadband CP antennas are realized. All radiating elements of antennas are 35 mm × 35 mm × 0.508 mm (0.187 λ0 × 0.187 λ0 × 0.0027 λ0 at 1.6 GHz) in size. The dual-band CP antenna has a measured S11 <-10-dB bandwidth of 226 MHz (1.473-1.699 GHz) and measured 3-dB axial ratio (AR) bandwidths of 12 MHz (1.530-1.542 GHz) and 35 MHz (1.580-1.615 GHz) with minimum AR CP frequencies of 1.535 GHz (AR = 0.26 dB) and 1.595 GHz (AR = 2.08 dB), respectively. The broadband CP antenna has a measured S11 <-10-dB bandwidth of 218 MHz (1.491-1.709 GHz) and a 3-dB AR bandwidth of 145 MHz (1.490-1.635 GHz). These compact antennas yield bidirectional electromagnetic fields with high radiation efficiency across their operational bandwidths.
Ta, SX, Park, I & Ziolkowski, RW 2017, 'Broadband Electrically Small Circularly Polarized Directive Antenna', IEEE Access, vol. 5, pp. 14657-14663.
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© 2013 IEEE. A broadband electrically small antenna with directive circularly polarized radiation is presented. It is composed of a compact single-feed crossed dipole driver, which is backed by a near-field resonant parasitic (NFRP) reflector to achieve the directive radiation pattern. The NFRP reflector is designed to generate extra resonances and minimum axial ratio (AR) points in the antenna system. These features are combined with those resulting from the driver to broaden the operational bandwidth. The proposed antenna was fabricated and measured. The antenna prototype, with a low profile (0.066 λ o at 1.45 GHz) and an electrically small size (ka = 0.71 at 1.45 GHz), has a measured S 11 < -10 dB bandwidth of 25.66% (1.362-1.763 GHz) and a 3-dB AR bandwidth of 10.56% (1.390-1.545 GHz). Additionally, the measurements resulted in a broadside gain of 2.31 ± 0.4 dBic and an average radiation efficiency of 80% within the operational bandwidth.
Tang, M-C, Chen, X, Li, M & Ziolkowski, R 2017, 'A Bandwidth-Enhanced, Compact, Single-Feed, Low-Profile, Multi-Layered, Circularly Polarized Patch Antenna', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 2258-2261.
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A bandwidth-enhanced, compact, single-feed, low-profile, multilayered, circularly polarized (CP) patch antenna is presented. A corner-truncated patch is introduced as a near-field resonant parasitic element directly beneath a specially engineered radiation patch. Without sacrificing the antenna's low profile and compact size, its presence not only introduces a new pair of orthogonal near-degenerate resonant modes, but also recovers a similar pair from the cross slot of the main patch. With the aid of both circular slots and meander-line slots on these patches, the resulting three pairs of adjacent near-degenerate modes have been successfully combined with the same clockwise polarization to enhance the CP bandwidth by more than a factor of two when compared to the same-height conventional single-layer patch antennas. Measured results are in good agreement with their simulated values and demonstrate that the reported antenna is low-profile: 0.016 λ0 , achieves a –10-dB impedance bandwidth of ∼4.6%, and a 3-dB axial-ratio bandwidth of about 2.33% along with realized gains of 4.5 ± 0.15 dBi, throughout that bandwidth. Analyses of the current distributions are used to explain the contributions of the parasitic patch, and further simulation studies validate our design guidelines and show its advantages.
Tang, M-C, Chen, Z, Wang, H, Li, M, Luo, B, Wang, J, Shi, Z & Ziolkowski, RW 2017, 'Mutual Coupling Reduction Using Meta-Structures for Wideband, Dual-Polarized, High-Density Patch Arrays', IEEE Transactions on Antennas and Propagation, vol. 65, no. 8, pp. 3986-3996.
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A mutual coupling reduction strategy that employs meta-structures is introduced for wideband, dual-polarized, high-density, planar, and patch antenna arrays. The meta-structures consist of two types of resonators: grounded capacitively loaded loops (GCLLs) and π -shaped elements. By incorporating the meta-structures into the array configuration, the isolation levels between adjacent radiating elements in both the E- and H-planes orientations are improved by as much as 7.15 dB. The surface current distribution behaviors of the array with only the GCLLs and with only the π -shaped elements are investigated thoroughly to explain the mutual coupling reduction mechanisms. A proof-of-concept array was constructed and tests were performed that validate the reported design principles and simulation results.
Tang, M-C, Shi, T & Ziolkowski, R 2017, 'Electrically Small, Broadside Radiating Huygens Source Antenna Augmented with Internal Non-Foster Elements to Increase Its Bandwidth', IEEE Antennas and Wireless Propagation Letters, vol. 16, pp. 712-715.
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A broadside radiating, linearly polarized, electrically small Huygens source antenna system that has a large impedance bandwidth is reported. The bandwidth performance is facilitated by embedding non-Foster components into the near-field resonant parasitic (NFRP) elements of this metamaterial-inspired antenna. High quality and stable radiation performance characteristics are achieved over the entire operational bandwidth. When the ideal non-Foster components are introduced, the simulated impedance bandwidth witnesses approximately a 17-fold enhancement over the passive case. Within this -10dB bandwidth, its maximum realized gain, radiation efficiency, and front-to-back ratio (FTBR) are, respectively, 4.00 dB, 88%, and 26.95 dB. When the anticipated actual negative impedance convertor (NIC) circuits are incorporated, the impedance bandwidth still sustains more than a 10-fold enhancement. The peak realized gain, radiation efficiency, and FTBR values are, respectively, 3.74 dB, 80%, and 28.01 dB, which are very comparable to the ideal values.
Tang, M-C, Shi, T & Ziolkowski, RW 2017, 'A Study of 28 GHz, Planar, Multi-Layered, Electrically Small, Broadside Radiating, Huygens Source Antennas', IEEE Transactions on Antennas and Propagation, vol. 65, no. 12, pp. 6345-6354.
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Two 28 GHz, planar, electrically small Huygens source antennas are presented that are broadside radiating and are based on multi-layer PCB technology. The designs seamlessly integrate electric Egyptian axe dipole (EAD) and magnetic capacitively loaded loop (CLL) near-field resonant parasitic (NFRP) elements with a coax-fed dipole radiator. Both linearly polarized (LP) and circularly polarized (CP) systems are demonstrated. The simulations of the LP system indicate that it is electrically small: ka = 0.961; has peak realized gains and front-to-back ratios (FTBRs) in the range from, respectively, 3.77 to 4.54 dBi and 7.16 to 33.92 dB; and radiation efficiencies higher than 81.14% over its entire 2.14%, -10-dB fractional impedance bandwidth (FBW-10dB). A prototype was fabricated and tested; the measured and simulated results are in good agreement. The CP system exhibits similar properties: ka = 0.942; 1.41% FBW-10dB with a 0.47% 3-dB axial ratio (AR) fractional bandwidth; and peak realized gain, FTBR, and radiation efficiency values equal to 2.03 dBi, 26.72 dB, and 73.4%, respectively. To confirm their efficacy for on-body applications, the specific absorption rate (SAR) values of both the LP and CP Huygens source antennas were evaluated and found to be very low.
Tang, MC, Wen, Z, Wang, H, Li, M & Ziolkowski, RW 2017, 'Compact, Frequency-Reconfigurable Filtenna with Sharply Defined Wideband and Continuously Tunable Narrowband States', IEEE Transactions on Antennas and Propagation, vol. 65, no. 10, pp. 5026-5034.
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© 1963-2012 IEEE. A compact, frequency-reconfigurable filtenna with sharp out-of-band rejection in both its wideband and continuously tunable narrowband states is presented. It is intended for use in cognitive radio applications. The wideband state is the sensing state and operationally covers 2.35-4.98 GHz. The narrowband states are intended to cover communications within the 3.05-4.39 GHz range, which completely covers the Worldwide Interoperability for Microwave Access (WiMAX) band and the satellite communications C-band. A p-i-n diode is employed to switch between these wide and narrowband operational states. Two varactor diodes are used to shift the operational frequencies continuously among the narrowband states. The filtenna consists of a funnel-shaped monopole augmented with a reconfigurable filter; it has a compact electrical size: 0.235λ L L × 0.392λ L , where the wavelength λ L corresponds to the lower bound of its operational frequencies. The measured reflection coefficients, radiation patterns, and realized gains for both operational states are in good agreement with their simulated values.
Tang, MC, Zhou, B & Ziolkowski, RW 2017, 'Low-Profile, Electrically Small, Huygens Source Antenna with Pattern-Reconfigurability That Covers the Entire Azimuthal Plane', IEEE Transactions on Antennas and Propagation, vol. 65, no. 3, pp. 1063-1072.
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© 1963-2012 IEEE. A pattern-reconfigurable, low-profile, efficient, electrically small, near-field resonant parasitic (NFRP), Huygens source antenna is presented. The design incorporates both electric and magnetic NFRP elements. The electric ones are made reconfigurable by the inclusion of a set of p-i-n diodes. By arranging these electric and magnetic NFRP elements properly, a set of three Huygens sources are attained, each covering a 120° sector. Pattern reconfigurability is obtained by switching the diodes on or off; it encompasses the entire 360° azimuth range. A prototype was fabricated and tested. The numerical and experimental studies are in good agreement. The experimental results indicate that in each of its instantaneous states at = 1.564$ GHz, the antenna provides uniform peak realized gains, front-to-back ratios, and radiation efficiencies, respectively, as high as 3.55 dBi, 17.5 dB, and 84.9%, even though it is electrically small: 0.92 , and low profile.
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.
Usman, M, Jan, MA & He, XS 2017, 'Cryptography-Based Secure Data Storage and Sharing Using HEVC and Public Clouds', Information Sciences, vol. 387, pp. 90-102.
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Mobile devices are widely used for uploading/downloading media files such as audio, video and images to/from the remote servers. These devices have limited resources and are required to offload resource-consuming media processing tasks to the clouds for further processing. Migration of these tasks means that the media services provided by the clouds need to be authentic and trusted by the mobile users. The existing schemes for secure exchange of media files between the mobile devices and the clouds have limitations in terms of memory support, processing load, battery power, and data size. These schemes lack the support for large-sized video files and are not suitable for resource-constrained mobile devices. This paper proposes a secure, lightweight, robust and efficient scheme for data exchange between the mobile users and the media clouds. The proposed scheme considers High Efficiency Video Coding (HEVC) Intra-encoded video streams in unsliced mode as a source for data hiding. Our proposed scheme aims to support real-time processing with power-saving constraint in mind. Advanced Encryption Standard (AES) is used as a base encryption technique by our proposed scheme. The simulation results clearly show that the proposed scheme outperforms AES-256 by decreasing the processing time up to 4.76% and increasing the data size up to 0.72% approximately. The proposed scheme can readily be applied to real-time cloud media streaming.
Wang, H, Nguyen, D, Dutkiewicz, Fang & Mueck 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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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, Ren, L, Mitchell, D, Casillas-Garcia, G, Ren, W, Ma, C, Xu, XX, Wen, S, Wang, F, Zhou, J, Xu, X, Hao, W, Dou, SX & Du, Y 2017, 'Enhanced energy transfer in heterogeneous nanocrystals for near infrared upconversion photocurrent generation.', Nanoscale, vol. 9, no. 47, pp. 18661-18667.
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The key to produce inorganic heterogeneous nanostructures, and to integrate multiple functionalities, is to enhance or at least retain the functionalities of different components of materials. However, this ideal scenario is often deteriorated at the interface of the heterogeneous nanostructures due to lattice mismatches, resulting in downgraded performance in most hybrid nanomaterials. Here, we report that there is a narrow window in controlling temperature in a Lewis acid-base reaction process to facilitate epitaxial alignment during the synthesis of hybrid nanomaterials. We demonstrate a perfectly fused NaYF4:Yb,Tm@ZnO heterogeneous nanostructure, in which the semiconductor ZnO shell can be epitaxially grown onto lanthanide-doped upconversion nanoparticles. By achieving a matched crystal lattice, the interface defects and crystalline grain boundaries are minimized to enable more efficient energy transfer from the upconversion nanoparticles to the semiconductor, resulting in both enhanced upconversion luminescence intensity and superior photoelectrochemical properties. This strategy provides an outstanding approach to endow lanthanide-doped upconversion nanoparticles with versatile properties.
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, Y, Liu, J, Li, Y, Fu, J, Xu, M & Lu, H 2017, 'Hierarchically Supervised Deconvolutional Network for Semantic Video Segmentation', Pattern Recognition, vol. 64, pp. 437-445.
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© 2016 Elsevier Ltd.Semantic video segmentation is a challenging task of fine-grained semantic understanding of video data. In this paper, we present a jointly trained deep learning framework to make the best use of spatial and temporal information for semantic video segmentation. Along the spatial dimension, a hierarchically supervised deconvolutional neural network (HDCNN) is proposed to conduct pixel-wise semantic interpretation for single video frames. HDCNN is constructed with convolutional layers in VGG-net and their mirrored deconvolutional structure, where all fully connected layers are removed. And hierarchical classification layers are added to multi-scale deconvolutional features to introduce more contextual information for pixel-wise semantic interpretation. Besides, a coarse-to-fine training strategy is adopted to enhance the performance of foreground object segmentation in videos. Along the temporal dimension, we introduce Transition Layers upon the structure of HDCNN to make the pixel-wise label prediction consist with adjacent pixels across space and time domains. The learning process of the Transition Layers can be implemented as a set of extra convolutional calculations connected with HDCNN. These two parts are jointly trained as a unified deep network in our approach. Thorough evaluations are performed on two challenging video datasets, i.e., CamVid and GATECH. Our approach achieves state-of-the-art performance on both of the two datasets.
Wazirali, R & Chaczko, Z 2017, 'Anticipatory quality assessment metric for measuring data hiding imperceptibility', Journal of Information Hiding and Multimedia Signal Processing, vol. 8, no. 2, pp. 404-412.
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© 2017 ISSN. Steganography is the art of writing concealed information in a way that it cannot arouse suspicion about its existence. The hidden data must not raise the attention of attackers to the existence of secret information in the host image. Therefore, ensuring high imperceptibility of the steganography is very essntial. Imperceptibility evaluation of the stego file can be determined by subjective or objective evaluation. Subjective evaluation is based on human judgment and opinion determining visual quality. This kind of evaluation, is not efficient as it is expensive, time consuming, and in any way cannot be referred to as an automatic system. On the other hand, objective metrics are based on mathematical concepts and might have poor correlation with subjective evaluation. This paper focuses on predicting the subjective quality using anticipatory objective Image Quality metric (IQM). The primary objective of this paper is to develop a systematic method of using HVS for image quality assessment. Moreover, the new metric method use a mathematical approaches for image quality measures predict the image quality measure basing on human perception.
Wong, H, Lin, W, Huitema, L & Arnaud, E 2017, 'Multi-Polarization Reconfigurable Antenna for Wireless Biomedical System', IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS, vol. 11, no. 3, pp. 652-660.
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Wong, SW, Deng, F, Wu, YM, Lin, JY, Zhu, L, Chu, QX & 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 (Q e ) 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.
Xu, M, Tang, Z, Yao, Y, Yao, L, Liu, H & Xu, J 2017, 'Deep Learning for Person Reidentification Using Support Vector Machines', Advances in Multimedia, vol. 2017.
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© 2017 Mengyu Xu et al. Due to the variations of viewpoint, pose, and illumination, a given individual may appear considerably different across different camera views. Tracking individuals across camera networks with no overlapping fields is still a challenging problem. Previous works mainly focus on feature representation and metric learning individually which tend to have a suboptimal solution. To address this issue, in this work, we propose a novel framework to do the feature representation learning and metric learning jointly. Different from previous works, we represent the pairs of pedestrian images as new resized input and use linear Support Vector Machine to replace softmax activation function for similarity learning. Particularly, dropout and data augmentation techniques are also employed in this model to prevent the network from overfitting. Extensive experiments on two publically available datasets VIPeR and CUHK01 demonstrate the effectiveness of our proposed approach.
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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Yang, N, Usman, M, He, XS, Jan, M & Zhang, L 2017, 'Time Frequency Filters Bank: A Simple Approach for Audio and Music Separation', IEEE Access, vol. 5, pp. 27114-27125.
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Blind Source Separation techniques are widely used in the field of wireless communication for a very long time to extract signals of interest from a set of multiple signals without training data. In this paper, we investigate the problem of separation of the human voice from a mixture of human voice and sounds from different musical instruments. The human voice may be a singing voice in a song or may be a part of some news, broadcast by a channel with background music. This paper proposes a generalized Short Time Fourier Transform (STFT)-based technique, combined with filter bank to extract vocals from background music. The main purpose is to design a filter bank and to eliminate background aliasing errors with best reconstruction conditions, having approximated scaling factors. Stereo signals in time-frequency domain are used in experiments. The input stereo signals are processed in the form of frames and passed through the proposed STFT-based technique. The output of the STFT-based technique is passed through the filter bank to minimize the background aliasing errors. For reconstruction, first an inverse STFT is applied and then the signals are reconstructed by the OverLap-Add method to get the final output, containing vocals only. The experiments show that the proposed approach performs better than the other state-of-the-art approaches, in terms of Signal-to-Interference Ratio (SIR) and Signal-to-Distortion Ratio (SDR), respectively.
Yang, T, Yang, L, Guo, J & 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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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 a 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 that 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 m (Bi)-CMOS Technology', IEEE ELECTRON DEVICE LETTERS, vol. 38, no. 10, pp. 1359-1362.
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Yang, Y, Simorangkir, RBVB, Zhu, X, Esselle, K & Xue, Q 2017, 'A Novel Boresight and Conical Pattern Reconfigurable Antenna with the Diversity of 360-degree Polarization Scanning', IEEE Transactions on Antennas and Propagation, vol. 65, no. 11, pp. 5747-5756.
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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 m 2 , excluding the pads, which is equivalent to 0.17 × 0.08 λ g 2 . (λ g is the guided wavelength at 23.5 GHz.)
Yang, Y, Zhu, Y, Zhou, J, Wang, F & Qiu, J 2017, 'Integrated Strategy for High Luminescence Intensity of Upconversion Nanocrystals', ACS Photonics, vol. 4, no. 8, pp. 1930-1936.
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© 2017 American Chemical Society. The growing applications of upconversion nanocrystals in bioimaging, therapeutics, and photonics have given rise to a demand of high quality nanocrystals with desirable luminescence intensity. Although the design of optimal nanocrystals such as core-shell nanostructures has improved the intensity, the internal links between dopant concentration balance, epitaxial growth protection, and shell thickness effect encounter a compromised situation that lacks of integrated consideration and comprehensive assessment. Here we propose an integrated strategy based on a core-shell design for the enhancement of upconversion luminescence intensity. Epitaxial protection can enable higher activator accommodation capacity in limited spatial scale, which leads to an Er 3+ concentration threshold improvement in β-NaYF 4 core-shell nanocrystals from 2 to 6 mol %. We further perform a comprehensive assessment of the nanocrystals with convincing performance improvement in ensemble spectroscopic intensity, upconversion quantum yield, and single nanocrystal intensity. Our findings provide improved understanding of electronic behaviors in multiphoton upconversion and opportunities for diverse applications requiring high quality upconversion nanocrystals.
Yao, Y, Zhang, J, Shen, F, Hua, X, Xu, J & Tang, Z 2017, 'A new web-supervised method for image dataset constructions', Neurocomputing, vol. 236, pp. 23-31.
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© 2017.The goal of this work is to automatically collect a large number of highly relevant natural images from Internet for given queries. A novel automatic image dataset construction framework is proposed by employing multiple query expansions. In specific, the given queries are first expanded by searching in the Google Books Ngrams Corpora to obtain a richer semantic descriptions, from which the visually non-salient and less relevant expansions are then filtered. After retrieving images from the Internet with filtered expansions, we further filter noisy images by clustering and progressively Convolutional Neural Networks (CNN) based methods. To evaluate the performance of our proposed method for image dataset construction, we build an image dataset with 10 categories. We then run object detections on our image dataset with three other image datasets which were constructed by weak supervised, web supervised and full supervised learning, the experimental results indicated the effectiveness of our method is superior to weak supervised and web supervised state-of-the-art methods. In addition, we do a cross-dataset classification to evaluate the performance of our dataset with two publically available manual labelled dataset STL-10 and CIFAR-10.
Yao, Y, Zhang, J, Shen, F, Hua, X, Xu, J & Tang, Z 2017, 'Exploiting Web Images for Dataset Construction: A Domain Robust Approach', IEEE TRANSACTIONS ON MULTIMEDIA, vol. 19, no. 8, pp. 1771-1784.
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Yuan, X, Saxena, D, Caroff, P, Wang, F, Lockrey, M, Mokkapati, S, Tan, HH & Jagadish, C 2017, 'Strong Amplified Spontaneous Emission from High Quality GaAs1-xSbxSingle Quantum Well Nanowires', Journal of Physical Chemistry C, vol. 121, no. 15, pp. 8636-8644.
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© 2017 American Chemical Society. Quantum confinement in semiconductor nanowires is of contemporary interest. Enhancing the quantum efficiency of quantum wells in nanowires and minimizing intrinsic absorption are necessary for reducing the threshold of nanowire lasers and are promising for wavelength tunable emitters and detectors. Here, we report on growth and optimization of GaAs 1-x Sb x /Al 1-y Ga y As quantum well heterostructures formed radially around pure zinc blende GaAs core nanowires. The emitted photon energy from GaAs 0.89 Sb 0.11 quantum well (1.371 eV) is smaller than the GaAs core, thus showing advantages over GaAs/Al 1-y Ga y As quantum well nanowires in photon emission. The high optical quality quantum well (internal quantum efficiency reaches as high as 90%) is carefully positioned so that the quantum well coincides with the maximum of the transverse electric (TE01) mode intensity profile. The obtained superior optical performance combined with the supported Fabry-Perot (F-P) cavity in the nanowire leads to the strong amplified spontaneous emission (ASE). Detailed studies of the amplified cavity mode are carried out by spatial-spectral photoluminescence (PL) imaging, where emission from nanowire is resolved both spatially and spectrally. Resonant emission is generated at nanowire ends and is polarized perpendicular to the nanowire, in agreement with the simulated polarization characteristics of the TE01 mode in the nanowire. The observation of strong ASE for single QW nanowire at room temperature shows the potential application of GaAs 1-x Sb x QW nanowires as low threshold infrared nanowire lasers.
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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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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© 2017 Wiley Periodicals, Inc. A 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 f c . The measured results show that the achieved 3-dB f c 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 0.005λ g 2 , 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.
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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, XS & 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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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. 1-8.
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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.
Zhao, Q, Luo, Y, Wang, W, Canning, J & Peng, GD 2017, 'Enhanced broadband near-IR luminescence and gain spectra of bismuth/erbium co-doped fiber by 830 and 980 nm dual pumping', AIP Advances, vol. 7, no. 4, pp. 1-9.
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© 2017 Author(s). A dual 830 and 980 nm pumping scheme is proposed aiming at broadening and flattening the spectral performance of bismuth/erbium codoped multicomponent fiber (BEDF). The spectral properties of distinct Bi active centers (BACs) associated with germanium (BAC-Ge), aluminium (BAC-Al), phosphorus (BAC-P) and silicon (BAC-Si) are characterized under single pumping of 830 and 980 nm, respectively. Based on the emission slope efficiencies of BAC-Al (∼1100 nm) and BAC-Si (∼1430 nm) under single pumping of 830 and 980 nm, the dual pumping scheme with the optimal pump power ratio of 25 (980 nm VS 830 nm) is determined to achieve flat, ultrabroadband luminescence spectra covering the wavelength range 950-1600 nm. The dual pumping scheme is further demonstrated on the on-off gain performance of BEDF. It is found under the pump power ratio of ∼8 (980 VS 830 nm), The gain spectrum has been flattened and broadened over 300 nm (1300-1600 nm) with an average gain coefficient of ∼1.5 dBm -1 . The spectral coverage is approximately 1.5 and 3 times wider compared to single pumping of 830 and 980 nm pumping, r espectively. The energy level diagrams of 830 and 980 nm are also constructed separately in view of the optical characteristic, which further clarifies the advantage for dual pumping. The proposed dual 830 and 980 nm pumping scheme with the multicomponent BEDF shows great potential in various broadband optical applications such as uniform ASE source, broadband amplifier and tuneable laser in NIR band.
Zhao, Q, Luo, Y, Wang, W, Canning, J & Peng, G-D 2017, 'Enhanced broadband near-IR luminescence and gain spectra of bismuth/erbium co-doped fiber by 830 and 980 nm dual pumping (vol 7, 045012, 2017)', AIP ADVANCES, vol. 7, no. 5.
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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.
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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.
Zheng, G, Fang, G, Shankaran, R, Orgun, MA, Zhou, J, Qiao, L & Saleem, K 2017, 'Multiple ECG Fiducial Points-Based Random Binary Sequence Generation for Securing Wireless Body Area Networks.', IEEE Journal of Biomedical and Health Informatics, vol. 21, no. 3, pp. 655-663.
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Generating random binary sequences (BSes) is a fundamental requirement in cryptography. A BS is a sequence of N bits, and each bit has a value of 0 or 1. For securing sensors within wireless body area networks (WBANs), electrocardiogram (ECG)-based BS generation methods have been widely investigated in which interpulse intervals (IPIs) from each heartbeat cycle are processed to produce BSes. Using these IPI-based methods to generate a 128-bit BS in real time normally takes around half a minute. In order to improve the time efficiency of such methods, this paper presents an ECG multiple fiducial-points based binary sequence generation (MFBSG) algorithm. The technique of discrete wavelet transforms is employed to detect arrival time of these fiducial points, such as P, Q, R, S, and T peaks. Time intervals between them, including RR, RQ, RS, RP, and RT intervals, are then calculated based on this arrival time, and are used as ECG features to generate random BSes with low latency. According to our analysis on real ECG data, these ECG feature values exhibit the property of randomness and, thus, can be utilized to generate random BSes. Compared with the schemes that solely rely on IPIs to generate BSes, this MFBSG algorithm uses five feature values from one heart beat cycle, and can be up to five times faster than the solely IPI-based methods. So, it achieves a design goal of low latency. According to our analysis, the complexity of the algorithm is comparable to that of fast Fourier transforms. These randomly generated ECG BSes can be used as security keys for encryption or authentication in a WBAN system.
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 mm 2 ( 0.126×0.3 mm 2 ).
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.
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© 2017 Yang Zhou et al. 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, 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 698-9 60 MHz, where a stable radiation pattern is achieved.
Ziolkowski, RW 2017, 'The directivity of a compact antenna: An unforgettable figure of merit', EPJ Applied Metamaterials, vol. 4.
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© R.W. Ziolkowski, published by EDP Sciences, 2017. When an electrically small antenna is conceived, designed, simulated, and tested, the main emphasis is usually placed immediately on its impedance bandwidth and radiation efficiency. All too often it is assumed that its directivity will only be that of a Hertzian dipole and, hence, its directivity becomes a minor consideration. This is particularly true if such a compact antenna radiates in the presence of a large ground plane. Attention is typically focused on the radiator and its size, while the ground plane is forgotten. This has become a too frequent occurrence when antennas, such as patch antennas that have been augmented with metamaterial structures, are explored. In this paper, it is demonstrated that while the ground plane has little impact on the resonance frequency and impedance bandwidth of patch antennas or metamaterial-inspired three-dimensional magnetic EZ antennas, it has a huge impact on their directivity performance. Moreover, it is demonstrated that with both a metamaterial-inspired two-element array and a related Huygens dipole antenna, one can achieve broadside-radiating electrically small systems that have high directivities. Several common and original designs are used to highlight these issues and to emphasize why a fundamental figure of merit such as directivity should never be overlooked.
Ziolkowski, RW 2017, 'Using huygens multipole arrays to realize unidirectional needle-like radiation', Physical Review X, vol. 7, pp. 1-13.
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For nearly a century, the concept of needle radiation has captured the attention of the electromagnetics communities in both physics and engineering, with various types of contributions reoccurring every decade. With the near-term needs for highly directive, electrically small radiators and scatterers for a variety of communications and sensor applications, superdirectivity has again become a topic of interest. While it is well known that superdirective solutions exist and suffer ill-posedness issues in principle, a detailed needle solution has not been reported previously. We demonstrate explicitly, for the first time, how needle radiation can be obtained theoretically from currents driven on an arbitrary spherical surface, and we explain why such a result can only be attained in practice with electrically large spheres. On the other hand, we also demonstrate, more practically, how broadside radiating Huygens source multipoles can be combined into an end-fire array configuration to achieve needle-like radiation performance without suffering the traditional problems that have previously plagued superdirectivity.
Abeywickrama, HV, Jayawickrama, BA, He, Y & Dutkiewicz, E 2017, 'Algorithm for Energy Efficient Inter-UAV Collision Avoidance', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), International Symposium on Communications and Information Technologies, IEEE, Cairns, Australia.
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aldebei, K, Farhood, H, Jia, W, Nanda, P & He, X 2017, 'Sequential and Unsupervised Document Authorial Clustering Based on Hidden Markov Model', Trustcom/BigDataSE/ICESS.2017, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE, Sydney.
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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 2017, 'A review of aggregation algorithms for the internet of things', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, International Conference on Systems Engineering, 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 2017, 'ETAM towards ICT teaching and learning studio for interactive learning in Information and Communication Technology', Proceedings of the 2017 16th International Conference on Information Technology Based Higher Education and Training, ITHET 2017, International Conference on Information Technology Based Higher Education and Training, 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.
Al-Manasia, M, Chaczko, Z & Ounzar, A 2016, '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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© 2016 IEEE. 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.
Alsawwaf, M & Chaczko, Z 2017, 'Multimodal access control: A review of emerging mechanisms', 5th Asia-pacific conference on computer aided systems engineering, 5th Asia-pacific conference on computer aided systems engineering, APCASE Foundation 2017, Guilin, China, pp. 46-49.
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One way to accomplish authentication is for a computer system to imple-ment a mechanism that allows access to critical information available through this system. In this context, critical information refers to contents of private data, access to a physical place, or access to a specific service. Often, advancements of technol-ogy lead to easier compromise of current biometrics, like fingerprint, voice, and retinal authentication. This review paper focuses on presenting and comparing emerging biometric modalities. Furthermore, it suggests a fusion of multiple meth-ods that can enable a more secure multimodal biometric access control system.
Alzughaibi, A & Chaczko, Z 2017, 'Human detection using illumination invariant feature extraction for natural scenes in big data video frames', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, 2017 25th International Conference on Systems Engineering, IEEE, Las Vegas, NV, USA, pp. 443-450.
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© 2017 IEEE. This research proposes a reliable machine learning based computational solution for human detection. The proposed model is specifically applicable for illumination-variant natural scenes in big data video frames. In order to solve the illumination variation problem, a new feature set is formed by extracting features using histogram of gradients (HoG) and linear phase quantization (LPQ) techniques, which are combined to form a single feature-set to describe features in illumination variant natural scenes. Pre-processing is applied to reduce the search space and improve results, and as the humans are in constant motion in the frames, a search space pruning algorithm is applied to reduce the search space and improve detection accuracy. Non-maximal suppression is also applied for improved performance. A Support Vector Machine (SVM) based classifier is used for fast and accurate detection. Most of the current state-of-the-art detectors face numerous problems including false, missed, and inaccurate detections. The proposed detector model shows good performance, which was validated using relevant UCF and CDW test data-sets. In order to compare the performance of the proposed methodology with the state-of-the-art detectors, some selected detected frames were chosen considering their Receiver Operating Characteristic (ROC) curves. These curves are plotted to compare and evaluate the results based on miss rates and true positives rates. The results show the proposed model achieves best results.
Antunes, N, Pipiras, V & Veitch, D 2017, 'Skampling for the Flow Duration Distribution', Proceedings of the 29th International Teletraffic Congress, ITC 2017, International Teletraffic Congress, 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.
Barua, S & Braun, R 2017, 'A Markovian Approach to the Mobility Management for the D2D Communication in 5G Cellular Network System', The Fifth Asia-Pacific.
Barua, S & Braun, R 2017, 'Mobility Management of D2D Communication for the 5G Cellular Network System : A Study and Result', Proceedings of the 2017 17th International Symposium on Communications and Information Technologies (ISCIT), International Symposium on Communications and Information Technologies, IEEE, Cairns, QLD, Australia, pp. 1-6.
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Wireless devices connected to the networks have been increasing remarkably for the last couple of decades. Ubiquitous voice and data connection are the key requisite for the next generation of wireless technology. Device to Device communication is widely known as D2D communication which is a new paradigm of cellular communication, and it was initially proposed to boost the network performance. It takes place when two devices communicate directly without taking significant help from the base station. Similar to other wireless communication systems, mobility management for the D2D communication is a big challenge which is yet to explore properly. Mobility management of D2D communications was enlightened in few papers. It should be managed in such a smart way in a cellular network that should enable lower latency, lower power consumptions, less complexity and last but not the least possible uninterrupted data connections which are primarily the requirements of next generations mobile cellular network. This paper extends our algorithm paradigm of mobility management of D2D communication that was proposed and published previously. We come up with the simulation results in this paper that validate our proposed model. However, we also highlight the D2D communications and mobility issues within it.
Bashir, MR & Gill, AQ 2017, 'IoT Enabled Smart Buildings: A Systematic Review', 2017 Intelligent Systems Conference (IntelliSys), Intelligent Systems Conference, IEEE, London, UK, pp. 151-159.
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There is an increasing interest in the Internet of Things (IoT) enabled smart buildings. The main question is: what are the key challenges, which must be addressed to effectively manage and analyze the big data for IoT enabled smart buildings. There is a need for the systematic literature review to understand the challenges and the solutions to overcome such challenges. Using the SLR approach, 22 relevant studies were identified and reviewed in this paper. The data from these selected studies were extracted to identify the challenges and relevant solutions. The findings from this research paper will serve as a knowledge base for researchers and practitioners for conducting further research and development in this important area.
Basnet, S, Jayawickrama, BA, He, Y & Dutkiewicz, E 2017, 'Considering switching overhead for transmit power allocation for GAA in spectrum access system', Proceedings of the 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, 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 2017, 'Opportunistic Access to PAL Channel for Multi-RAT GAA Transmission in Spectrum Access System', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, 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.
Baum, TC, Nicholson, KJ, Ghorbani, K & Ziolkowski, RW 2017, 'Passive and active metamaterial-inspired radiating and scattering systems integrated into structural composite materials', 2017 11th International Congress on Engineered Material Platforms for Novel Wave Phenomena, Metamaterials 2017, International Congress on Engineered Material Platforms for Novel Wave Phenomena, IEEE, Marseille, France, pp. 400-402.
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© 2017 IEEE. Several passive and active meta-structures have been successfully integrated into load-bearing high performance aerospace structural composite materials. These include an electrically small, metamaterial-inspired Egyptian Axe Dipole (EAD) antenna; a high impedance ground plane (HIGP) to mitigate any cross talk between adjacent antennas; and passive and active circuits including wide bandwidth and conformal amplifiers, bias-Tees, and powered LEDs. Several different manufacturing techniques have been tested and the outcome is a well-defined manufacturing process. These structures enable streamlined aerodynamic functional smart skins.
Baum, TC, Ziolkowski, RW, Ghorbani, K & Nicholson, KJ 2017, 'Investigation of a conformal amplifier embedded in an aerospace composite structure', European Microwave Week 2017: "A Prime Year for a Prime Event", EuMW 2017 - Conference Proceedings; 47th European Microwave Conference, EuMC 2017, European Microwave Conference, IEEE, Nuremberg, Germany, pp. 588-591.
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© 2017 European Microwave Association. This paper has investigated the implementation of a conformal amplifier embedded into a high performance aerospace composite quartz fiber re-enforced polymer (QFRP) matrix. A cyanate ester resin system provided by Lonza (PT-30) was used to encapsulate the quartz fibers (Astroquartz II) and the passive/active elements. This enabled a streamlined aerodynamic functional skin to be formed over the leading edge of an airfoil. Apart from the active amplifier component, a passive bias-tee and power LED were also integrated into the skin. The conformal amplifier performance was measured and found to have low-loss and acceptable impedance matching between 0.01 GHz and 1.0 GHz. The amplifier gain is above 10 dB up to 2.0 GHz. The successful manufacturing process for this conformal amplifier has demonstrated the ability to integrate novel microwave circuits into composite materials on a highly conformal surface.
Bautista, MG, Dutkiewicz, E & Yang, Y 2017, 'Design of a compact self-coupled resonator and dual-band bandpass filter in 0.13-μm CMOS technology for millimetre-wave application', Progress in Electromagnetics Research Symposium, Progress in Electromagnetics Research Symposium - Fall, IEEE, Singapore, Singapore, pp. 2653-2658.
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© 2018 Electromagnetics Academy. All rights reserved. Design of a miniaturized resonator and its application for dual-band bandpass filter design for millimeter-wave application is presented in this paper. Both the resonator and filter are implemented in a standard 0.13-μm (Bi)-CMOS technology. The performance is extensively verified using an EM simulator from NI-AWR. Using the presented resonator structure, two transmission zeros can be generated and effectively controlled. By feeding the resonator using a capacitive coupling technique, a dual-band bandpass filter that operated at 40 GHz with insertion loss of −0.7 dB and at 71 GHz with insertion loss of −1.5 dB, respectively. The proposed design achieves a reduced layout size of 302 μm × 131 μm.
Bautista, MG, Yang, Y & Dutkiewicz, E 2017, 'Compact on-chip 60 GHz resonator with ring defected ground structure for millimetre-wave applications', HNICEM 2017 - 9th International Conference on Humanoid, Nanotechnology, Information Technology, Communication and Control, Environment and Management, International Conference on Humanoid, Nanotechnology, Information Technology, Communication and Control, Environment and Management, IEEE, Manila, Philippines, pp. 1-4.
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© 2017 IEEE. This paper presents a design of a miniaturized resonator for millimeter-wave applications. The resonator is implemented in a standard 0.13μm (Bi)CMOS technology. Its performance is verified using an EM simulator from NI-AWR. The designed resonator is based on a unique structure, a combination of spiral loop and meander line structure. The ground plane is characteristically altered with a ring defected ground structure (DGS) to enhance the overall performance. The resonator design exhibits tuning flexibility at its resonance frequency within the mm-wave spectrum that is proportional to its design dimension. By using capacitive feeding, the designed resonator generates one transmission zero at 60 GHz with insertion loss of -2.7 dB and -29.4 dB return loss respectively. The chip size of the resonator excluding the pads is only 116 μm × 236 μm (0.027mm2).
Bautista, MG, Zhu, JB, Zhu, F, Yang, Y & Dutkiewicz, E 2017, 'Design of on-chip quadrature hybrid (3dB) branch-line couplers in 0.13-μm SiGe technology for millimetre-wave applications', Proceedings of the 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, 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 mm2and 0.21 mm2, respectively, which indicates an area reduction by 13% and 30% respectively.
Bou Ghantous, G & Gill, A 2017, 'DevOps: Concepts, Practices, Tools, Benefits andChallenges', PACIS2017; Proceedings 96, PACIS2017, AIS Electronic Library (AISeL), Malaysia.
Braun, R & Chaczko, Z 2017, 'Using Matlab modeling in cody to teach Teletraffic engineering', 2017 16th International Conference on Information Technology Based Higher Education and Training, ITHET 2017, pp. 1-5.
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Cabrera, E, Fang, G & Vesilo, R 2017, 'Adaptive Hybrid ARQ (A-HARQ) for Ultra-Reliable Communication in 5G', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, NSW, Australia, pp. 1-6.
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© 2017 IEEE. In this paper, we address the need for motivating applications, such as mission critical industrial control and medical applications, to operate under the Ultra-Reliable Communication (URC) mode in the future 5th Generation (5G) cellular wireless networks, while also under strict Quality of Service (QoS) constraints such as ultra-low latency. Reliability has been shown to improve by using Hybrid Automatic Repeat reQuest (HARQ) for the retransmission (RTX) of erroneous packets during poor channel conditions. However, this can increase the delay to unacceptable levels if more than 1 RTX is required. Thus, an Adaptive HARQ (A-HARQ) scheme is proposed, where RTX are done on better quality sub-bands, with resources dynamically allocated based on Channel Quality Indicator (CQI) reports. A-HARQ also increases the number of RTX within a 4 ms time period, by utilising Transmission Time Interval (TTI) bundling to decrease the delay incurred from many RTX. A performance analysis is conducted, where A-HARQ was shown to have about 35% lower delay than the legacy HARQ, with a slight decrease in throughput, for low Signal-to-Noise (SNR) values.
Cai, Y, Zhang, Y, Ding, C, Qian, Z & Liu, J 2017, 'Design of multilayer SIW cavity-backed slot antenna array', 2017 11th European Conference on Antennas and Propagation, EUCAP 2017, European Conference on Antennas and Propagation, 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.
Canning, J 1970, 'Can water be used as a novel electro-optic material within optical fibres?', OSA Workshop on Specialty Optical Fibres (WSOF), Cyprus.
Canning, J 2017, 'Explaining Anomalous Large Electro-Optic Coefficients In Poled Silica Optical Fibres', Conf. Lasers & ElectroOptics Pacific Rim (CLEO), Optoelectronics Comm. Conf. (OECC) & Photonics Global Conf. (PGC), Singapore.
Canning, J 2017, 'Photonics in Smart Sensing Networks', IEEE 2nd Int. Conf. on Fibre-Optic and Photonic Sensors for Industrial and Safety Applications (OFSIS), IEEE, Brisbane.
Canning, J 2017, 'Smart Sensing & Photonic INVITED', ), Conf. Lasers & ElectroOptics Pacific Rim (CLEO), Optoelectronics Comm. Conf. (OECC) & Phot. Global Conf. (PGC), Singapore.
Canning, J 2018, 'Smart Sensing & Photonics', https://www.photind.eu/conference-cleo-pr-oecc-pgc-2017/, Conf. Lasers & ElectroOptics Pacific Rim (CLEO), Optoelectronics Comm. Conf. (OECC) & Phot. Global Conf. (PGC), Singapore (2017)., Singapore.
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https://www.photind.eu/conference-cleo-pr-oecc-pgc-2017/
Canning, J 2017, 'Smart Sensing & Photonics', Optoelectronics Forum, Jinan University Guangzhou.
Canning, J, Cook, K, Hossain, A, Han, C, Athanaze, T & Chartier, L 2017, 'Characterisation of 3D printers using fibre Bragg gratings', Proceedings of SPIE, Optical Fiber Sensors, Society of Photo-optical Instrumentation Engineers, Jeju, Korea, pp. 1-4.
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The extrusion nozzles of three low cost desktop 3D printers are characterised using optical fibre Bragg gratings. Temperature profiles show remarkably consistent distributions pointing to operation as good quality micro-furnaces potentially not only for 3D printing but also optical fibre drawing.
Canning, J, Gordon, L, Burton, T, Benson, P, Sharon, S, Freeman-Acquah, E, Petrucco, C, Cook, K, Stone, J, Boughton, P & Johnstone, D 1970, 'Shedding light on Parkinon’s disease: A safe, noninvasive, disease-modifying treatment', 56th Meeting of Australian Society for Medical Research, Sydney.
Canning, J, Gordon, L, Burton, T, Freeman-Acquah, E, Cook, K, Stone, J, Boughton, P & Johnstone, D 2017, 'Neuroprotection against Parkinson’s disease with targeted remote photobiomodulation', Bosch Inst. Annual Scient. Meeting, Sydney.
Canning, J, Han, C, Cook, K & Hossain, A 2017, 'Light-induced Au surface modification', Proceedings of SPIE, Optical Fiber Sensors, Society of Photo-optical Instrumentation Engineers, Jeju Korea.
Canning, J, Han, C, Cook, K & Hossain, M 1970, 'Tuning the wettability of gold', https://www.osapublishing.org/conference.cfm?meetingid=89, Conf. Lasers & ElectroOptics Pacific Rim (CLEO), Optoelectronics Comm. Conf. (OECC) & Photonics Global Conf. (PGC), Singapore (2017)., Signapore.
Canning, J, Hossain, M, Cook, K & Ast, S 2017, 'Photo- and thermal degradation of olive oil measured using an optical fibre smartphone spectrofluorimeter', Proceedings of SPIE, Optical Fiber Sensors Conference, Society of Photo-optical Instrumentation Engineers, Jeju, South Korea.
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Degradation of olive oil under light and heat are analysed using an optical fibre based low-cost portable smartphone spectrofluorimeter. Visible fluorescence bands associated with phenolic acids, vitamins and chlorophyll centred at λ ~ 452, 525 and 670 nm respectively are generated using near-UV excitation (LED λ ex ~370 nm), of extra virgin olive oil are degraded more likely than refined olive oil under light and heat exposure. Packaging is shown to be critical when assessing the origin of degradation.
Canning, J, Martelli, C, da Silva, J, Pipa, D, da Silva, M, Zamarreño, C, Schafauser, P, Dutra, G, Daciuk, R, Galvão, J, Mezzadri, F, Renzo, A, Dreyer, U, Webber, G, Janeczko, C & da Rocha, O 2017, 'Photonic sensors: from horse racing to horse power', Proceedings of SPIE, Optical Fiber Sensors, Society of Photo-optical Instrumentation Engineers, Jeju Korea.
Canning, J, Wang, W, Tafti, G, Karpisz, T, Cook, K, Luo, Y & Peng, G-D 2017, 'Optimal pressure for tuning the lattice structure of photonic crystal fibre', 3rd Aust. & NZ Conf. Optics & Photonics, Queenstown, New Zealand.
Chaczko, Z & Braun, R 2017, '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, International Conference on Information Technology Based Higher Education and Training, IEEE, Ohrid, Macedonia.
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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 2017, 'Road vehicle alert system using IOT', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, 2017 25th International Conference on Systems Engineering, 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.
Chaczko, Z, Sethi, H & Alsawwaf, MK 2017, 'An Overview of Multi-layer Security System Using Biometrics', 5th Asia-Pacific Conference on Computer Aided System Engineering, 5th Asia-Pacific Conference on Computer Aided System Engineering, APCASE Foundation, Guilin, China, pp. 68-70.
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After years of research on biometrics, still the authentication and verification of a human being is at risk. Many challenges have been faced by the system to authenticate a human on the basis of their biometric trait. The design of this paper is such that it focuses on three main biometric techniques to extract the various features of a human body contour for authentication and verification purposes. This paper presents an approach towards voice recognition patterns, face geometry patterns and gait pattern analysis to increase the accuracy and precision of the system.
Chen, SL, Qin, PY & Guo, YJ 2017, 'Multi-linear polarization reconfigurable center-fed circular patch antenna with shorting posts', 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings, 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, SL, Qin, PY, Guo, YJ, Liu, Y & You, P 2017, 'Array pattern synthesis using numerical pattern synthesis algorithm including mutual coupling', Proceedings of the 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings, 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 2017, '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, X, Ni, W, Chen, T, Collings, IB, Wang, X, Liu, RP & Giannakis, GB 2017, 'Distributed Stochastic Optimization of Network Function Virtualization', 2017 IEEE Global Communications Conference, GLOBECOM 2017 - Proceedings, IEEE Global Communications Conference, IEEE, Singapore, Singapore, pp. 1-6.
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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,log 2 (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.
Cheng, Nguyen, D, Dutkiewicz & Mueck 2017, 'Preserving Operational Information in Spectrum Access System with Dishonest Users', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), International Symposium on Communications and Information Technologies, IEEE, Cairns, QLD, Australia.
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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.
Cheng, Q, Dutkiewicz, Fang, G, Shi, Z, Nguyen, D & Wang, H 2017, 'A Novel Full-Duplex Spectrum Sensing Algorithm for OFDM Signals in Cognitive Radio Networks', GLOBECOM 2017 - 2017 IEEE Global Communications Conference, IEEE Global Communications Conference, IEEE, Singapore.
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Full duplex (FD) capability enables a "listen and talk" protocol for spectrum sensing that has been used as a new paradigm to increase the spectrum utilization in cognitive radio networks (CRNs). However, the spectrum sensing performance suffers from the imperfect self-interference suppression (SIS). This could significantly degrade the performance of FD systems in CRNs. In this paper, we investigate the issue of spectrum sensing with imperfect SIS in FD systems. By drawing support from a cyclic prefix (CP) of Orthogonal Frequency Division Modulation (OFDM) signals, we propose a novel spectrum sensing mechanism that is robust to self- interference. Comparing with other conventional sensing approaches in FD systems, the proposed method is independent of timing delay. That significantly improves the sensing performance, even without requiring a complex process for timing delay estimation. As a result, it also reduces the overhead of spectrum sensing. Extensive simulation results indicate that even with serious self-interference and timing delay, the presented approach is still able to achieve much higher performance than the conventional energy detection and waveform-based detection approaches.
Chenhu, G, Geng, J, Zhou, B, Li, J, Chen, Y, Zhu, W, Liang, X, Jin, R & Ziolkowski, RW 2017, 'A T-shaped feed structure to enhance the performance of a polarization diversity antenna', 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings, IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, San Diego, CA, USA, pp. 2143-2144.
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© 2017 IEEE. In this paper, a T-shaped feed structure is presented that enhances the performance of a polarization diversity antenna. It is a four-port network that consists of two input ports and two output ports. The -10 dB relative impedance bandwidth is 6.64 GHz from 2.31GHz to 8.95 GHz, i.e., 117.9%; and the isolation is at least 29.7 dB within the same band. Furthermore, the insertion loss is less than 0.5 dB in that band between 2.33GHz to 8.93 GHz.
Chiu, C, Chaczko, Z & Yu, Z 2017, '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.
Cook, K, Canning, J, Bandyopadhyay, S, Lancry, M, Martelli, C, Jin, T & Csipkes, A 2017, 'Overview of high temperature fibre Bragg gratings', Optics InfoBase Conference Papers.
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© 2018 Optics InfoBase Conference Papers. All rights reserved. Various types of high temperature fibre Bragg gratings (FBGs) for sensing applications, are briefly reviewed, discussing their various figures of merit and performance.
Cook, K, Canning, J, Bandyopadhyay, S, Lancry, M, Martelli, C, Jin, T & Csipkes, A 2017, 'Overview of high temperature fibre Bragg gratings', 2017 Conference on Lasers and Electro-Optics Pacific Rim, CLEO-PR 2017, Conference on Lasers and Electro-Optics Pacific Rim, IEEE, Singapore, Singapore, pp. 1-3.
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© 2017 IEEE. All rights reserved. Various types of high temperature fibre Bragg gratings (FBGs) for sensing applications, are briefly reviewed, discussing their various figures of merit and performance.
Dasgupta, A & Gill, AQ 2017, 'Fog Computing Challenges: A Systematic Review', Australasian Conference on Information Systems, Hobart, Australia.
Ding, C, Jones, B, Sun, H, Qin, PY, Guo, YJ & Ji, L 2017, 'Wideband feeding method for full-wave dipole', 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings, IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 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%.
Duong, T, Nguyen, N, Vu, V, Zhu, F, Nguyen, D & Dutkiewicz 2017, 'Quad-Band Antenna for GSM/WSN/WLAN/LTE-A Application in IoT Devices', 2017 17th International Symposium on Communications and Information Technologies (ISCIT), International Symposium on Communications and Information Technologies, 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.
Dutkiewicz, E 2017, 'VTC2017-Spring Welcome from the General Chair', IEEE Vehicular Technology Conference, IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE, Sydney, NSW, Australia.
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Dutkiewicz, E, He, Y, Jayawickrama, BA & Abeywickrama, HV 2017, 'Radio Environment Maps Generation and Spectrum Sensing Testbed for Spectrum Sharing in 5G Networks', PROCEEDINGS OF THE 2017 IEEE-APS TOPICAL CONFERENCE ON ANTENNAS AND PROPAGATION IN WIRELESS COMMUNICATIONS (APWC), IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Verona, ITALY, pp. 33-36.
Dutkiewicz, E, Jayawickrama, BA & He, Y 2017, 'Radio spectrum maps for emerging IoT and 5G networks: Applications to smart buildings', ICECOS 2017 - Proceeding of 2017 International Conference on Electrical Engineering and Computer Science: Sustaining the Cultural Heritage Toward the Smart Environment for Better Future, International Conference on Electrical Engineering and Computer Science, 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.
Fang, LF, LI, H, Huang, D & Huang, X 2017, 'A Low Cost Interpolation Based Detection Algorithm for Medium-size Massive MIMO-OFDM Systems', the 17th International Symposium on Communications and Information Technologies, Cairns, Australia.
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Farhood, H, He, XS, Jia, W, Blumenstein, M & Li, H 2017, 'Counting People based on Linear, Weighted and Local Random Forest', Prcoeedings of the 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), The International Conference on Digital Image Computing: Techniques and Applications, IEEE, Sydney, pp. 1-7.
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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.
Gao, X, Du, J, Zhang, T & Guo, YJ 2017, 'Design of a Monolithic-Integrated Circularly-Polarized Antenna-Coupled High-T-c Superconducting Terahertz Harmonic Mixer', PROCEEDINGS OF THE 2017 IEEE-APS TOPICAL CONFERENCE ON ANTENNAS AND PROPAGATION IN WIRELESS COMMUNICATIONS (APWC), IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Verona, ITALY, pp. 324-325.
Gay, M, Zhu, F, Nguyen, D & Dutkiewicz 2017, 'Double-Balanced Gilbert Mixer with Current Bleeding for RF Front-End Using 0.13µm SiGe BiCMOS Technology', Proc. of the IEEE 85th Vehicular Technology Conference 2017, IEEE Vehicular Technology Conference, IEEE, Sydney, Australia, pp. 1-5.
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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.
Giampietro, C, Chaczko, Z, De La Villefromoy, M & Braun, R 2017, '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, International Conference on Information Technology Based Higher Education and Training, IEEE, Ohrid, Macedonia, pp. 3-6.
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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.
Gill, AQ, Behbood, V, Ramadan-Jradi, R & Beydoun, G 2017, 'IoT architectural concerns: a systematic review', Proceedings of the Second International Conference on Internet of things, Data and Cloud Computing, International Conference on Internet of things and Cloud Computing, ACM, Cambridge, United Kingdom, pp. 1-9.
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There is increasing interest in studying and applying Internet of Things (IoT) within the overall context of digital-physical ecosystems. Most recently, much has been published on the benefits and applications of IoT. The main question is: what are the key IoT architectural concerns, which must be addressed to effectively develop and implement an IoT architecture? There is a need to systematically review and synthesize the literature on IoT architectural challenges or concerns. Using the SLR approach and applying customised search criteria derived from the research question, 22 relevant studies were identified and reviewed in this paper. The data from these papers were extracted to identify the IoT architectural challenges and relevant solutions. These results were organised into to 9 major challenge and 7 solution categories. The results of this research will serve as a resource for practitioners and researchers for the effective adoption, and setting future research priorities and directions in this emerging area of IoT architecture.
Gineste, M, Deleu, T, Cohen, M, Chuberre, N, Saravanan, V, Frascolla, V, Mueck, M, Strinati, EC & Dutkiewicz, E 2017, 'Narrowband IoT service provision to 5G User Equipment via a satellite component', 2017 IEEE GLOBECOM WORKSHOPS (GC WKSHPS), IEEE Globecom Workshops, IEEE, Singapore, SINGAPORE.
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Today an estimated 15 billion of connected objects communicate with each other''s. These connected objects that compose the Internet of Things (IoT) are expected to extend to 50 or 80 billion worldwide by 2020. Bringing wide-area connectivity for the IoT using satellite technology is therefore an attractive solution to complement terrestrial networks, allowing densification and coverage extension in remote areas. This paper deals with seamless integration of satellites and high altitude platforms (HAPS) into 5G networks. It describes the necessary modifications to operate on 5G systems in order to take satellite and HAPS specifics into account. Link budget calculations and system dimensioning, including channel modeling, are provided to determine the required satellite and HAPS performance as well as to estimate the number of served users per km2.
Gordon, LC & Chaczko, Z 2017, 'Ontological metamodel for consistency of data heritage preservation (DHP)', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, 2017 25th International Conference on Systems Engineering, 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.
Gu, S, Lu, Y, Zhang, L & Zhang, J 2017, '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, SpringerLink, 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.
Guo, J, Yuan, J & Zhang, JA 2017, 'Wireless Device-to-Device Caching Networks with Distributed MIMO and Hierarchical Cooperations', 2017 IEEE Global Communications Conference, GLOBECOM 2017 - Proceedings, IEEE Global Communications Conference, 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, YJ & Qin, PY 2017, 'Single-layer reflectarrays - Past, present and future', 2017 11th European Conference on Antennas and Propagation, EUCAP 2017, European Conference on Antennas and Propagation, 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.
Haider, N, Dutkiewicz, E, Nguyen, DN, Mueck, M & Srikanteswarae, S 2017, 'The Impact on Full Duplex D2D Communication of Different LTE Transmission Techniques', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE Vehicular Technology Conference, IEEE, Sydney, Australia, pp. 1-5.
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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.
Hakami, H & Chaczko, Z 2017, 'Reversible color compression transform for big data system using human visual system', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, International Conference on Systems Engineering, IEEE, Las Vegas, NV, USA, pp. 459-465.
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© 2017 IEEE. In today’s life, images play a significant role in many Big Data application fields for various purposes. Image processing has to face the huge challenges because of images created in a digital format which leads to huge data volumes. Using Joint Photographic Experts Group 2000 (JPEG2000) compression techniques to meet the diverse type of real-time applications. Lossless compression JPEG2000 and others are used to minimize the expenditure of possessions such as hard disk space and transmission bandwidth. This experimental work shows an improved lossless color image compression that uses a wavelet based Human Visual System. This Reversible Color Compression Transform method (RCCT) produces an efficient algorithm to compress the image without loss of information. JPEG2000 as a lossless mode is utilized for bit-preserving and to refer globally for encoding and decoding processes. The Reversible Color Transform (RCT) is used in JPEG 2000 using wavelets which provide a mathematical way to encode the information in such a way that it is layered according to the level of detail by using HVS attributes in the stage of quantization. In this research, the goal of lossless image compression is to decrease the number of bits required to demand computing resources such as store and transmit images without any loss of information.
He, X, Mohapatra, P, Sandhu, R, Guo, S, Di Martino, B, Lu, J, Mosse, D & Pasricha, S 2017, 'Message from the IEEE TrustCom/BigDataSE/ICESS 2017 General 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, p. xvi.
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Hoang, DT, Niyato, D, Wang, P & Kim, DI 2017, 'Optimal time sharing in RF-powered backscatter cognitive radio networks', IEEE International Conference on Communications, IEEE International Conference on Communications (ICC), 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, Kim, DI & Le, LB 2017, 'Overlay RF-powered backscatter cognitive radio networks: A game theoretic approach', IEEE International Conference on Communications, IEEE International Conference on Communications (ICC), 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.
Hou, Z, Yang, Y, Zhu, X, Liao, S, Shum, M & Xue, Q 2017, '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), IEEE MTT-S International Microwave Symposium, IEEE, Honolulu, Hawaii, pp. 843-846.
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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.
Hou, ZJ, Xue, Q, Yang, Y, Zhu, X & Dutkiewicz, E 2017, 'Miniaturized millimeter-wave on-chip bandpass filter design in 0.13-μm SiGe BiCMOS technology', Proceedings of the 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, 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 2017, 'A 320 GHz On-Chip Slot Antenna Array Using CBCPW Feeding Network in 0.13-mu m SiGe Technology', 2017 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM (IMS), IEEE-Microwave-Theory-and-Techniques-Society International Microwave Symposium (IMS) / Session on Women in Microwaves (WIM), IEEE, Honolulu, HI, pp. 839-842.
Huang, X, Zhang, JA, Guo, YJ & Rahman, ML 2017, 'Signal Stripping Based Sensing Parameter Estimation in Perceptive Mobile Networks', IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications, IEEE, Verona, Italy.
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Abstract:
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.
Hussein, F & Piccardi, M 2017, 'Minimum-Risk Structured Learning of Video Summarization', 2017 IEEE International Symposium on Multimedia (ISM), IEEE International Symposium on Multimedia, 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.
Huynh T, TB, Vo K, T, Ngo H, S, Dutkiewicz, E & Nguyen, D 2016, 'A Local Search Algorithm for Saving Energy Cost in Duty-Cycle Wireless Sensor Network', Intelligent and Evolutionary Systems The 20th Asia Pacific Symposium, IES 2016, Canberra, Australia, November 2016, Proceedings, Asia Pacific Symposium, Intelligent and Evolutionary Systems, Springer, Canberra, Australia.
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Wireless Sensor Networks (WSNs) have been recently used for various applications. Due to the distributed and (often) unattended nature of the nodes after deployment, the lack of energy and the interruptive process in each sensor are the two major problems of WSN systems. Hence, designing a protocol which not only improves system performance but also lowers sensors’ energy consumption so as to maximize the network lifetime is very much desirable. The network lifetime maximization problem was known to be NP-Hard. This paper addresses the Minimum Energy-Multicasting (MEM) problem in Duty-Cycle Wireless Sensor Networks (DC-WSNs) in which sensors cyclically switch between on/off (wake/sleep) modes. To that end, we propose a local search algorithm and compare its performance with the best algorithm so far called GS-MEM over the four datasets designated for the MEM problem. The experimental results show that our proposed algorithm significantly outperforms GS-MEM in terms of energy cost
Ismaiel, B, Abolhasan, M, Smith, D, Ni, W & Franklin, D 2017, 'A Survey and Comparison of Device-to-Device Architecture Using LTE Unlicensed Band', IEEE Vehicular Technology Conference, 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, D, Ni, W & Franklin, D 2017, 'Scalable MAC protocol for D2D communication for future 5G networks', 2017 14th IEEE Annual Consumer Communications and Networking Conference, CCNC 2017, 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.
Ji, LY, Zhu, HL, Qin, PY & Jay Guo, Y 2017, 'Broadband partially reflective surface antenna with tapered corrugated ground', Proceedings of the 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings, 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.
Jiang, J, Chaczko, Z, Al-Doghman, F & Narantaka, W 2017, 'New LQR protocols with intrusion detection schemes for IOT security', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, International Conference on Systems Engineering, 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, Qiang, W & Zhang, J 2017, 'Part-based Data Association for Visual Tracking', Proceedings of Digital Image Computing: Techniques and Applications (DICTA), 2017 International Conference on, International Conference on Digital Image Computing: Techniques and Applications, IEEE, Sydney, NSW, Australia, pp. 1-8.
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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
Kadi, A, Kutay, CM & Canning, J 2017, 'Flipped Learning not Flopped Learning', Website Proceedings of the 28th Australasian Association for Engineering Education Conference, Australasian Association for Engineering Education Conference, AAEE, Manly, pp. 1-8.
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Context Introducing Flipped Learning across the University of Technology Sydney (UTS)
was trialled through the Faculty of Engineering and IT (FEIT). It raised concerns on how to
implement such a teaching program in skill-based subjects that had strong elements of core
competencies centred on communication, understanding and critical analysis. Rather than
revert to conventional teaching when half a class fails to prepare, an alternative approach for
motivating students to read and study the material was needed. We had to demonstrate to
students an advantage in preparing for class if active engagement was to take place. This
may include peer assessing of each other’s work, presentations by expert staff on alternative
perspectives, or application of the content being taught beyond the assessable items
Purpose In order to encourage intrinsic motivation in study we wish to allow students to
manage their own study and engage with material in their own time. This experience will
increase their confidence to approach problems themselves if they receive timely feedback.
One of the aspects of Flipped Learning that academics consider the most difficult is to
enforce preparation for class work. We describe here some more conducive approaches to
encourage students to engage with preparation material, including pre-submitting work for
sharing in the tutorial. We provide some case studies of strategies, from those doing face-toface
courses ,to engage their students. We wish to show that there are a variety of ways to
provide this added benefit for students,
Approach The paper provides case studies from approaches that have been shared
amongst staff during staff development workshops run by Teaching and Learning in FEIT at
the UTS. Some strategies to engage students who have prepared for a class, and hence
provide intrinsic motivation for preparation, are:
1. Provide immediate feedback as they go through the preparation material; e.g. a quiz
designed to cement concepts learnt in...
Kale, A & Chaczko, Z 2017, 'iMuDS: An internet of multimodal data acquisition and analysis systems for monitoring urban waterways', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, International Conference on Systems Engineering, 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 solution can be ...
Karmokar, DK & Guo, YJ 2017, 'Planar Leaky-Wave Antennas for Low-Cost Radar', PROCEEDINGS OF THE 2017 IEEE-APS TOPICAL CONFERENCE ON ANTENNAS AND PROPAGATION IN WIRELESS COMMUNICATIONS (APWC), IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE, Verona, ITALY, pp. 112-115.
Kong, F, Sun, X, Leung, VCM, Guo, YJ, Zhu, Q & Zhu, H 2017, 'Queue-aware small cell activation for energy efficiency in two-tier heterogeneous networks', IEEE Wireless Communications and Networking Conference, WCNC, IEEE Wireless Communications and Networking Conference, 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.
Kusakunniran, W, Wu, Q & Zhang, J 2017, 'Action Recognition based on Correlated Codewords of Body Movements', Proceedings of the 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), International Conference on Digital Image Computing: Techniques and Applications, IEEE, Sydney, Australia, pp. 1-8.
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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.
Kusakunniran, W, Wul, Q, Ritthipravad, P & Zhang, J 2017, 'Three-stages hard exudates segmentation in retinal images', 2017 9th International Conference on Information Technology and Electrical Engineering, ICITEE 2017, 2017 9th International Conference on Information Technology and Electrical Engineering, 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.
Lai, W, Ni, W, Wang, H & Liu, RP 2017, 'Decentralized relaying and performance analysis in vehicular ad hoc networks', IEEE Vehicular Technology Conference, Vehicular Technology Conference, 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.
Lancry, M, Cook, K, Cao, J, Billotte, T, Poumellec, B & Canning, J 2017, 'Study of stress relaxation in UV regenerated fiber bragg gratings', Optics InfoBase Conference Papers, Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference, IEEE, Munich, Germany.
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Harsh environmental sensing using fiber Bragg grating (FBG) technologies is a rapidly growing field of research. A new generation of devices that operate in extreme environments (particularly those operating above 800°C) including environments with additional challenges such as radiation and intense optical fields (e.g. high power lasers), must be capable of withstanding gradual annealing and degradation, or aging, over time while preserving their intrinsic advantages (multiplexing capabilities, electromagnetic immunity, low intrusivity, mechanical reliability) in comparison to thermocouples. Of particular local relevance these include live diagnostics with optical sensor embedded into high-temperature composites for aircraft, helicopters and space infrastructure, temperature and pressure sensing in increasingly deeper and hotter oil bores, and the monitoring and mapping of temperature distribution at power plants, furnaces and chemical reactor. Much of the answer is related to inherent glass structure and properties, particularly viscous flow, chemical migration and stress relaxation. Thermal stability may therefore be achieved by judicious application of glass preparation, glass annealing and glass laser irradiations. FBG regeneration process [1] is the only current approach that can enable photonic technologies to operate in such harsh environments at elevated temperatures. In this paper we investigated the mechanisms of FBG thermal regeneration and in particular glass relaxation processes using micro-Raman, surface topography measurements and SEM
Lancry, M, Cook, K, Poumellec, B & Canning, J 1970, 'Study of stress relaxation in UV regenerated fibre Bragg gratings', https://www.osapublishing.org/conference.cfm?meetingid=89, Singapore.
Le, AT, Huang, XJ & Guo, YJAY 2017, 'On Performance of Analog Least Mean Square Loop for Self-Interference Cancellation in In-Band Full-Duplex OFDM Systems', Proceedings of the 85th IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, Australia, pp. 1-5.
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This paper evaluates the performance of analog least
mean square (ALMS) loop employed to cancel self-interference in
orthogonal frequency division multiplexing (OFDM) in-band fullduplex
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 system primarily depends
on windowing function rather than pulse shaping as in single
carrier system. It is also noticed that the ALMS loop in OFDM
systems gives much higher level of sel-interference suppression
because OFDM signals lead to reduce the error of the interference
channel modelling with the adaptive filter. Simulation is then
conducted to verify the theoretical findings.
LI, H, Wang, Q, Huang, X & Zhang, JA 2017, 'Low-Complexity Uplink Multiuser Receivers for MIMO System with Massive Hybrid Array', Proceedings of the 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), IEEE Vehicular Technology Conference, IEEE, Sydney, Australia, pp. 1-5.
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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, Wu, H, He, X, Lin, S, Wang, R & Luo, X 2017, 'Multi-view pairwise relationship learning for sketch based 3D shape retrieval', Proceedings - IEEE International Conference on Multimedia and Expo, IEEE International Conference on Multimedia and Expo, IEEE, Hong Kong, China, pp. 1434-1439.
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© 2017 IEEE. Recent progress in sketch-based 3D shape retrieval creates a novel and user-friendly way to explore massive 3D shapes on the Internet. However, current methods on this topic rely on designing invariant features for both sketches and 3D shapes, or complex matching strategies. Therefore, they suffer from problems like arbitrary drawings and inconsistent viewpoints. To tackle this problem, we propose a probabilistic framework based on Multi-View Pairwise Relationship (MVPR) learning. Our framework includes multiple views of 3D shapes as the intermediate layer between sketches and 3D shapes, and transforms the original retrieval problem into the form of inferring pairwise relationship between sketches and views. We accomplish pairwise relationship inference by a novel MVPR net, which can automatically predict and merge the pairwise relationships between a sketch and multiple views, thus freeing us from exhaustively selecting the best view of 3D shapes. We also propose to learn robust features for sketches and views via fine-tuning pre-trained networks. Extensive experiments on a large dataset demonstrate that the proposed method can outperform state-of-the-art methods significantly.
Li, K, Ni, W, Duan, L, Abolhasan, M & Niu, J 2017, 'SWPT: A Joint-Scheduling Model for Wireless Powered Sensor Networks', 2017 IEEE Global Communications Conference, GLOBECOM 2017 - Proceedings, 2017 IEEE Global Communications Conference, 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, SL, Qin, PY & Guo, YJ 2017, '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, European Conference on Antennas and Propagation, 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, Q, Tan, Z, Jamdagni, A, Nanda, P, He, X & Han, W 2017, 'An Intrusion Detection System Based on Polynomial Feature Correlation Technique', Proceedings of the 2017 IEEE Trustcom/BigDataSE/ICESS, 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE Computer Society, Sydney, pp. 978-983.
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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 2017, 'Fine-Grained Access Control for Personal Health Records in Cloud Computing', Proceedings of the 95th IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, 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, X, Ma, L, Shankaran, R, Orgun, M & Fang, G 2017, 'Joint mode selection and proportional fair scheduling for D2D communication', IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC, Annual International Symposium on Personal, Indoor, and Mobile Radio Communication, IEEE, Montreal, QC, Canada, pp. 1-6.
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© 2017 IEEE. In this paper, we propose a new joint mode selection and proportional fair scheduling scheme for Device-to-Device (D2D) communication in cellular networks. Our objective is to maximize the sum of all users' proportional fairness functions while guaranteeing the signal-to-interference-plus-noise ratio (SINR) requirements of both D2D and cellular links. In our scheme, we consider two communication mode options for D2D communication: the dedicated mode and the reuse mode. In order to improve the fairness of the D2D users (DUs), we allocate the dedicated radio resource to the D2D pair with a higher priority. Furthermore, we use the Hungarian Algorithm to implement the sub-optimal resource allocation for multiple D2D pairs in the reuse mode and their reuse cellular users (CUs). The simulation results demonstrate that both the system throughput and the system fairness experience significant increases in our proposed scheme.
Lin, S, Yu, J, Ni, W & Liu, R 2017, 'Radio Resource Management for Ultra-Dense Smallcell Networks: A Hybrid Spectrum Reuse Approach', Proceedings of the 85th IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, 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, W & Ziolkowski, RW 2017, 'Compact, omni-directional, circularly-polarized mm-Wave antenna for device-to-device (D2D) communications in future 5G cellular systems', 10th Global Symposium on Millimeter-Waves, GSMM 2017, Global Symposium on Millimeter-Waves, IEEE, Hong Kong, China, pp. 115-116.
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© 2017 IEEE. A simple, compact, omni-directional, circularly-polarized (CP) millimeter-wave antenna for Device-to-Device (D2D) communications in the next generation (5G) cellular systems is reported. It is a CP omni-directional antenna operating at 28 GHz for mobile terminals. The antenna combines a vertical electric monopole element with four magnetic elements to coherently excite parallel electric and magnetic dipoles. This combination generates the omni-directional CP radiation. The overlapping -10-dB impedance and 3-dB axial ratio (AR) bandwidth is from 27 to 28.5 GHz, which covers the 28 GHz frequency band proposed for 5G mobile cellular networks (i.e., from 27.5 to 28.35 GHz). The antenna has an omni-directional radiation pattern at 28 GHz whose peak realized RHCP gain is 2.08 dBic and whose 3-dB AR beamwidth is wide, from elevation angles 3° to 136°. Mass production of the antenna is possible by PCB manufacturing technologies. The overall size is 3.44 mm × 3.44 mm × 1 mm (ka = 1.1017). Consequently, it could be embedded in many current popular, smart wireless devices such as cell phones, laptops, digital watches, and smart glasses as well as their future versions for operation in 5G cellular networks.
Lin, W & Ziolkowski, RW 2017, 'Electrically-Small, Low-Profile, Dual-Linear and Circularly Polarized Huygens Dipole Antennas with Broadside Radiation Patterns', 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings, IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, San Diego, CA, USA, pp. 547-548.
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© 2017 IEEE. Electrically-small, low-profile, broadside-radiating Huygens dipole antennas are reported that have high radiation efficiencies and are either dual-linear (LP) or circularly (CP) polarized. The Huygens behavior, i.e., a high front-to-back ratio, is realized by exciting two complementary electric and magnetic dipole radiators, simultaneously having the same amplitude and phase. To achieve this design, we modified the electrically-small near-field resonant parasitic (NFRP) Egyptian axe dipole (EAD) antenna to act as the electric radiator and the capacitively loaded loop (CLL) NFRP antenna to act as the magnetic radiator. By organically combining the crossed EAD and CLL NFRP elements together with proper excitations by a pair of driven dipole elements, the resulting electrically small antenna generates broadside Huygens radiation patterns with either dual-LP or CP characteristics. They have ka = 0.87; are low-profile, ~0.04λ; exhibit good radiation performance with 4.54 dBi LP and 4.58 dBic CP peak realized gains; have > 20 dB front-to-back ratios; and have > 93.9% radiation efficiencies at their resonant frequencies. These antenna systems are quite suitable for narrow bandwidth applications including, e.g., wireless power transfer (WPT) to charge batteries in wireless sensors, unmanned aerial vehicles (UAVs), and other compact portable devices.
Lin, W, Ziolkowski, RW & Tang, MC 2017, 'Electrically small, low profile, broadside radiating LP and CP Huygens dipole antennas', Proceedings of the 2017 International Symposium on Antennas and Propagation, ISAP 2017, International Symposium on Antennas and Propagation, IEEE, Phuket, Thailand, pp. 1-2.
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© 2017 IEEE. Electrically small Huygens dipole antennas are reported that are low profile, broadside radiating, have high radiation efficiencies, and are either linear (LP) or circularly (CP) polarized. The Huygens behavior, i.e., a high front-To-back ratio with a cardioid-like pattern, is realized by exciting two (LP) or two pairs (CP) of complementary electric and magnetic dipole radiators, simultaneously having the same amplitude and proper phase. These designs are achieved with near-field resonant parasitic (NFRP) Egyptian axe dipole (EAD) elements that act as the electric radiators and capacitively loaded loop (CLL) NFRP elements that act as the magnetic radiators. By efficiently combining the crossed EAD and CLL NFRP elements together with proper excitations by a single (LP) or a pair (CP) of driven dipole elements, the resulting electrically small antennas generate broadside Huygens radiation patterns. They have ka < 1.0, are low-profile, ≤ 0.04 λ0; exhibit good radiation performance with better than 4.5 dBi LP and 4.5 dBic CP peak realized gains; have > 20 dB front-To-back ratios; and have > 90% radiation efficiencies at their resonant frequencies. These antenna systems are quite suitable for a variety of compact narrow bandwidth applications including wireless power transfer (WPT), unmanned aerial vehicles (UAVs), and on-and off-body sensor networks.
Movassaghi, S, Maleki, B, Smith, DB & Abolhasan, M 2017, 'Biologically inspired self-organization and node-level interference mitigation amongst multiple coexisting wireless body area networks', Proceedings of the 2017 13th International Wireless Communications and Mobile Computing Conference, IWCMC 2017, International Wireless Communications and Mobile Computing Conference, 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.
Mueck, M, Choi, S, Bender, P, Ivanov, V, Jin, Y, Ahn, H, Kim, K & Dutkiewicz, E 2017, 'Radio Equipment Directive - A novel Software Reconfiguration Framework', 2017 IEEE Globecom Workshops (GC Wkshps), IEEE Globecom Workshops, IEEE, Singapore, Singapore, pp. 1-4.
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The European Commission recently published the revision of the novel Radio Equipment Directive 2014/53/EU replacing the R&TTE Directive which has been in force since 1999. This Directive represents the basic regulation framework for the making available of radio equipment on the Single European Market. Among several changes, the new RED includes specific provisions enabling the usage Software Reconfiguration for Radio Equipment in Europe. At the same time, ETSI has developed a novel Software Radio Reconfiguration framework specifically meeting the requirements of the Directive and encompassing technical, certification and security solutions. This paper introduces and comments the related changes on the regulation level and introduces the ETSI solution which is ready to be applied for new type of radio equipment to be introduced in Europe.
Mukunthan, A, Cooper, C, Safaei, F, Franklin, D & Abolhasan, M 2017, 'Leveraging the Propagation Model to Make Greedy Routing Decisions in Urban Environments', Proceedings of the 85th IEEE Vehicular Technology Conference, 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, Z 2017, 'A Framework for Data Security in Cloud using CollaborativeIntrusion Detection Scheme', SIN'17: Proceedings of the 10th International Conference on Security of Information and Networks, International Conference On Security Of Information And Networks, ACM Digital Library, Jaipur, India, pp. 188-193.
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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
Nan, Y, Huang, X & Guo, YJ 2017, 'A Generalized Continuous Wave Synthetic Aperture Radar', Proceedings of the 85th Vehicular Technology Conference, Vehicular Technology Conference, IEEE, Sydney, Australia, pp. 1-5.
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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 GCWSAR
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 2017, 'Passive Synthetic Aperture Radar Imaging with Piecewise Constant Doppler Algorithm', 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications, IEEE, Veorna, Italy.
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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, Jamdagni, A & Puthal, D 2017, 'Secure-GLOR: An Adaptive Secure Routing Protocol for Dynamic Wireless Mesh Networks', 2017 IEEE Trustcom/BigDataSE/ICESS, 16th IEEE International Conference on Trust, Security and Privacy in Computing and Communications, IEEE Computer Society, Sydney, Australia, pp. 269-276.
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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
Nguyen, T, Hoang, D, Nguyen, D & Seneviratne, A 2017, 'Initial Trust Establishment for Personal Space IoT Systems', Proc. of the 2017 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS): MobiSec 2017, IEEE Conference on Computer Communications Workshops, IEEE, Atlanta, USA, pp. 784-789.
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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.
Peng, K, Parkinson, P, Gao, Q, Boland, JL, Li, Z, Wang, F, Wenas, YC, Davies, CL, Fu, L, Johnston, MB, Tan, HH & Jagadish, C 2017, 'Broadband Single-Nanowire photoconductive terahertz detectors', 2017 Conference on Lasers and Electro-Optics, CLEO 2017 - Proceedings, pp. 1-2.
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© 2017 IEEE. Broadband photoconductive terahertz detectors based on undoped InP single nanowires were demonstrated. By further design and growth of an axial n+-i-n+ structure to reduce the contact resistance, highly-sensitive n+-i-n+ InP single-nanowire terahertz detectors were achieved.
Pham, TT, Nguyen, DN, Dutkiewicz, E, McEwan, AL & Leong, PHW 2017, 'An Anomaly Detection Technique in Wearable Wireless Monitoring Systems for Studies of Gait Freezing in Parkinson’s Disease', International Conference on Information Networking, International Conference on Information Networking, IEEE, Da Nang, Vietnam, pp. 41-45.
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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 2017, 'Wearable Healthcare Systems: A Single Channel Accelerometer Based Anomaly Detector for Studies of Gait Freezing in Parkinson’s Disease', Proceedings of the IEEE, IEEE International Conference on Communications (ICC), Institute of Electrical and Electronics Engineers, Paris, France.
Qin, PY, Chen, SL & Guo, YJ 2017, 'A compound reconfigurable microstrip antenna with agile polarizations and steerable beams', Proceedings of the 2017 International Symposium on Antennas and Propagation, International Symposium on Antennas and Propagation, 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.
Rafiei, A, Abolhasan, M, Franklin, DR, Safaei, F, Smith, S & Ni, W 2017, 'Effect of the number of participating nodes on recovery of WSN coverage holes', 2017 27th International Telecommunication Networks and Applications Conference, ITNAC 2017, International Telecommunication Networks and Applications Conference, IEEE, 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, ML, Zhang, J, Huang, X & Guo, YJ 2017, 'Analog Antenna Array based Sensing in Perceptive Mobile Networks', Proceedings of the 2017 IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications (APWC), IEEE-APS Topical Conference on Antennas and Propagation in Wireless Communications, IEEE, Veorna, Italy.
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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
Sadra, S & Abolhasan, M 2017, 'On improving the saturation performance of IEEE802.15.6-based MAC protocols in Wireless Body Area Networks', Proceedings of the 2017 13th International Wireless Communications and Mobile Computing Conference, IWCMC 2017, International Wireless Communications and Mobile Computing Conference, 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.
Simorangkir, RBVB, Yang, Y & Esselle, K 2017, '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 2017, 'Performance of embroidered higher-order mode antennas with different stitching patterns', 2017 11th European Conference on Antennas and Propagation, EUCAP 2017, 2017 11th European Conference on Antennas and Propagation, 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, K & Diao, Y 2017, 'A Varactor-Tuned Frequency Reconfigurable Fabric Antenna Embedded in Polymer: Assessment of Suitability for Wearable Applications', Proceedings of the 2017 IEEE MTT-S International Microwave Symposium (IMS), 2017 IEEE MTT-S International Microwave Symposium, IEEE, Honolulu, Hawaii, pp. 204-207.
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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 device
Sinha, S & Chaczko, Z 2017, 'Concepts and observations in artificial endocrine systems for IoT infrastructure', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, International Conference on Systems Engineering, 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.
Siyari, P, Krunz, M & Nguyen, D 2017, 'Joint Transmitter- and Receiver-based Friendly Jamming in a MIMO Wiretap Interference Network', 2017 IEEE International Conference on Communications Workshops (ICC Workshops), IEEE International Conference on Communications Workshops, IEEE, Paris, France, pp. 1-6.
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We consider an interference network tapped by external eavesdropper(s) in which each legitimate transmit-receive pair conceals its communications by using joint transmit-based friendly jamming (TxFJ) and receiver-based friendly jamming (RxFJ). Specifically, TxFJ is realized at the transmit side using MIMO precoding while RxFJ is achieved at the receiver side of each link by leveraging the state-of-the-art self-interference-suppression techniques (allowing a radio to cancel the self-interference effect of its transmit signal). We show that with a careful power allocation between the information signal and TxFJ at the transmit side of each link, the corresponding receiver is able decide on using RxFJ independent of any multi-user interference factor. This ability sets the receivers free from having to measure multi-user interference at eavesdropper(s). With every link following such strategy, we model this interaction as a non-cooperative game. We derive sufficient conditions under which the game admits a unique Nash equilibrium. We then propose a robust version of the game that requires only statistical knowledge of eavesdropping channel.
Siyari, P, Krunz, M & Nguyen, DN 2017, 'Joint Transmitter- and Receiver-based Friendly Jamming in a MIMO Wiretap Interference Network', 2017 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS WORKSHOPS (ICC WORKSHOPS), IEEE International Conference on Communications (ICC) / Wireless Communications Symposium / 3rd Workshop on Optical Wireless Communications (OWC), IEEE, Paris, FRANCE, pp. 1323-1328.
Song, H, Wu, Q & Dong, H 2017, 'EMI-based diagnosis to grounding grids by combining ensemble empirical mode decomposition and ICA', ACM International Conference Proceeding Series, International Conference on Computer Modeling and Simulation, ACM DL, 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.
Sun, H, Ding, C, Guo, YJ & Mittra, R 2017, 'A wideband dipole antenna based on a non-uniformly segmented structure', Proceedings of the 2017 11th European Conference on Antennas and Propagation, EUCAP 2017, European Conference on Antennas and Propagation, 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 2017, 'Design of an Elliptic Filter Using Multiple-Loop Feedback Structure in CMOS Technology for Analogue Signal Processing', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, 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.
Sun, Y, Zhu, X & Bautista, MG 2017, 'Design of fifth-order LF 0.05° equiripple linear phase lowpass filter with gain boost using nauta transcondutor', 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, IEEE, Cairns, QLD, Australia, pp. 1-4.
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© 2017 IEEE. In this paper a leapfrog feedback filter architecture that uses only single-ended input and single-ended output (SISO) transconductors and grounded capacitors is described. The filter structure has all circuit nodes containing a grounded capacitor and requires only simple transconductors, thus suitable for higher frequency applications. To show the high frequency capability, a fifth-order linear phase UHF filter with gain boost has been designed using Nauta transconductor. This may be the first time that Nauta transcodunctors are used in HDD read channels.
Ta, SX, Park, I & Ziolkowski, RW 2017, 'Bandwidth and F-B Ratio Enhancements of an Electrically-Small Crossed-Dipole Antenna Using an NFRP Reflector', 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings, IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, San Diego, CA, USA, pp. 543-544.
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© 2017 IEEE. In this paper, a compact single-feed crossed-dipole antenna backed by a near-field resonant parasitic (NFRP) element is proposed to enhance the bandwidth and front-to-back (F-B) ratio of the electrically small antenna system. The NFRP element is designed to not only act as a reflector, but also to generate an extra resonance with circularly polarized (CP) radiation for the antenna system. The extra resonances are utilized to broaden the antenna bandwidth. The final design with an overall size of 35 mm ´ 35 mm ´ 13.7 mm (0.184λ o ´ 0.184λ o ´ 0.072λ o at 1.575 GHz) has a |S 11 | < −10 dB bandwidth of 20.3% (1.485–1.820 GHz), a 3-dB axial ratio bandwidth of 9.46% (1.510–1.660 GHz), and a maximum F-B ratio of 9.8 dB. Relative to the crossed-dipole antenna without a reflector, the proposed design increases the F-B ratio from 0 to 9.8 dB and achieves approximately 150% and 400% increases in |S 11 | < −10 dB and 3-dB AR bandwidths, respectively.
Ta, SX, Park, I & Ziolkowski, RW 2017, 'Broadband Circularly Polarized NFRP Antenna Using Crossed Dipole Driver', 2017 11TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 11th European Conference on Antennas and Propagation (EUCAP), IEEE, Paris, FRANCE, pp. 1972-1975.
Tafti, G, Wang, W, Karpisz, T, Canning, J, Cook, K, Luo, Y & Peng, G-D 2017, 'Fabrication and structure of Hi-Bi Micro-structured optical fibre', 3rd Aust. & NZ Conf. Optics and Photonics (ANZCOP),, Queenstwon NZ.
Takalkar, M & Xu, M 2017, 'Image based Facial Micro-Expression Recognition using Deep Learning on Small Datasets', Proceedings of Digital Image Computing: Techniques and Applications (DICTA), 2017 International Conference on, The International Conference on Digital Image Computing: Techniques and Applications, IEEE, Sydney, Australia, pp. 1-7.
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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.
Tan, Z, Jamdagni, A & Liu, RP 2017, 'Message from the SECSOC 2017 Workshop 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, p. xxxi.
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Tang, MC & Ziolkowski, RW 2016, 'Efficient, electrically small metamaterial-inspired antennas with high directivity', 2016 International Symposium on Antennas and Propagation (ISAP), International Symposium on Antennas and Propagation, IEEE, Okinawa, Japan, pp. 16-17.
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© 2016 IEICE. It has been demonstrated that metamaterial-inspired electrically small antennas (ESAs) can be designed to have high radiation efficiencies and even large bandwidths with non-Foster circuit augmentations. However, being electrically small, it still remains a challenge to obtain directivities over interesting bandwidths which exceed those of simple dipoles, especially with only passive constructs. Different classes of passive and active metamaterial-inspired ESAs that have successfully produced higher directivities and higher bandwidths will be reviewed. Recently reported configurations will be highlighted in our presentation.
Tang, M-C & Ziolkowski, RW 2017, 'Electrically Small Metamaterial-Inspired Antennas with Active Near Field Resonant Parasitic Elements: From Theory to Practice', 2017 11TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP), 11th European Conference on Antennas and Propagation (EUCAP), IEEE, Paris, FRANCE, pp. 1559-1562.
Tang, MC, Shi, T & Ziolkowski, RW 2017, 'Design of a planar electrically small huygens source antenna', 2017 International Applied Computational Electromagnetics Society Symposium in China, ACES-China 2017, International Applied Computational Electromagnetics Society Symposium, IEEE, Suzhou, China, pp. 1-2.
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© 2017 Applied Computational Electromagnetics Society. A 28 GHz, planar, electrically small Huygens source antenna is presented. The proposed antenna is composed of electric Egyptian axe dipole (EAD) and magnetic capacitively loaded loop (CLL) near-field resonant parasitic (NFRP) elements with a coax-fed dipole radiator. It has broadside radiating and planar performance characteristics. To confirm its efficacy for on-body applications, the specific absorption rate (SAR) values of the Huygens source antenna are evaluated and found to be very low.
Tang, M-C, Shi, T & Ziolkowski, RW 2017, 'A 28-GHz, Multi-Layered, Circularly Polarized, Electrically Small, Huygens Source Antenna', 2017 IEEE 5TH INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY (EMC-BEIJING), 5th IEEE International Symposium on Electromagnetic Compatibility (EMC-Beijing), IEEE, Beijing Univ Posts & Telecommunicat, Beijing, PEOPLES R CHINA.
Tian, J, Liu, RP & Lin, SJ 2017, 'A Markov chain analysis model of IEEE 802.11p', Proceedings of the 2017 International Conference on Wireless Communications, Networking and Applications, 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.
Umair, A, Nanda, P & He, X 2017, '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, 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.
Venemyr, GO, Bakken, BT, Kionig, L, Ranglund, OJS, Holen, S, Haave, H, Vold, T & Braun, R 2017, 'Flipped gaming for enhanced learning outcome crisis preparedness courses', Proceeidngs of Information Technology Based Higher Education and Training (ITHET), 2017 16th International Conference on, International Conference on Information Technology Based Higher Education and Training, IEEE, Ohrid, Macedonia, pp. 1-4.
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Preparing for crisis and incidents have gained an increased focus, also within the educational system. At The Inland University of Applied Sciences, Campus Rena, in Norway, a Bachelor study is developed to cater for the increased need for educating staff not only in municipalities, but also in private organizations. Regulations and governmental instructions have also created a void between staff that can and know how to handle crisis and staff that need to know how to handle crisis. In addition, the preparedness issue, in order to avoid crisis, has received a lot of attention. The study has until recently been a mix of ordinary classroom education and exercises, both live and table top exercises, both which is costly and time consuming both in planning and execution. Two years ago, some faculty staff and a small group of students started to look into using games for educational purposes. Some of the games were free ware and downloadable from the internet, another game was developed by Bohemia Interactive Simulations (https://bisimulations.com/). Combining using MeTracker (http://www.concorde-project.eu/index.php/results/developments/the-training-tools/1-metracker) for organizing the work during a training process, and the developed game, this has proved to be a powerful tool for learning about how to be prepared for and handle crisis. Even if the initial costs for development and licenses have been somewhat substantial, the tools will provide the students with a unique possibility of simulating crisis in a higher volume than what is possible using live exercises. So far, the faculty staff has developed the scenarios for the students to play. The change from this is now to use a game based environment to play scenarios developed by the students themselves. The students that have tested this is in the third year of their study and the preliminary feedback from the students on this approach has been positive. The paper presents the results from interviews and observ...
Vo, A, Diep Nguyen, Kha Ha & Eryk Dutkiewicz 2017, 'Subject-Independent P300 BCI using Ensemble Classifier, Dynamic Stopping and Adaptive Learning', GLOBECOM 2017 - 2017 IEEE Global Communications Conference, IEEE Global Communications Conference, IEEE, Singapore.
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Brain-computer interfaces (BCIs) are used to assist people, especially those with verbal or physical disabilities, communicate with the computer to indicate their selections, control a device or answer questions only by their mere thoughts. Due to the noisy nature of brain signals, the required time for each experimental session must be lengthened to reach satisfactory accuracy. This is the trade-off between the speed and the precision of a BCI system. In this paper, we propose a unified method which is the integration of ensemble classifier, dynamic stopping, and adaptive learning. We are able to both increase the accuracy, as well as to reduce the spelling time of the P300-Speller. Another merit of our study is that it does not require the training phase for any new subject, hence eliminates the extensively time-consuming process for learning purposes. Experimental results show that we achieve the averaged bit rate boost up of 182% on 15 subjects. Our best achieved accuracy is 95.95% by using 7.49 flashing iterations and our best achieved bit rate is 40.87 bits/min with 83.99% accuracy and 3.64 iterations. To the best of our knowledge, these results outperformed most of the related P300-based BCI studies.
Vo, A, Nguyen, DN, Kha, HH & Dutkiewicz, E 2017, 'Dynamic stopping using eSVM scores analysis for event-related potential brain-computer interfaces', 2017 11th International Symposium on Medical Information and Communication Technology (ISMICT), International Symposium on Medical Information and Communication Technology, IEEE, Lisbon, Portugal.
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In brain-computer interface (BCI) research, there must be a trade-off between accuracy and speed of the BCI system, especially those based on event-related potentials (ERPs). This paper proposes a novel method which can significantly increase the spelling bit rate while also maintaining the desired accuracy. We provide an adaptive real-time stopping method based on the scores of ensemble support vector machine classifiers. We apply a criteria assessment process on the classifiers' scores to dynamically stop the ERP-evoked paradigms at any flashing sequence. Our experiments were conducted on three different P300-Speller data sets (BCI Competition II, BCI Competition III and Akimpech). Our proposed framework significantly outperformed the related state-of-the-art studies in terms of character output accuracy and elicitation bit rate rise between static and dynamic stopping schemes. We improve the average bit rate by over 80% while perfectly maintaining the best original static accuracy of over 96%.
Vo, K, Nguyen, D, Ha, K & Dutkiewicz 2017, 'Real-Time Analysis on Ensemble SVM Scores to Reduce P300-Speller Intensification Time', Proc. of the 39th Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC'17), Annual International Conference of the IEEE Engineering in Medicine & Biology Society, IEEE, Korea, pp. 4383-4386.
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In most Brain-Computer Interface systems, especially
the P300-Speller, there must be a harmonized balance
between the accuracy and the spelling time. One major drawback
of the classical 36-choice P300-Speller is the slow rate
of character elicitation. This paper aims to propose a realtime
signal processing method to decrease the spelling time by
exploiting the score margins of the ensemble Support Vector
Machine classifiers during real-time P300-Speller flashes, rather
than just getting the classifiers’ highest scores. Our experiments
were conducted on the dataset of the BCI Competition III and
resulted in a successful character rate of over 96% with just
approximately 15 to 20 seconds for each character spelling
session. As compared with the fixed 31.5 seconds of the best
original approach of the competition, our proposed method
significantly reduces the required spelling time by over 30%
while maintaining the desired classification accuracy
Vold, T, Bergum, S, Ranglund, OJS, Kionig, L, Bakken, G, Kaloudis, A & Braun, R 2017, 'Student input—A case of an extended flipped classroom', Information Technology Based Higher Education and Training (ITHET), 2017 16th International Conference on, International Conference on Information Technology Based Higher Education and Training, IEEE, Ohrid, Macedonia, pp. 1-6.
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The idea from Socrates about the knowledge being a part of the students' knowledge base or ability of combining accessible knowledge forms the backdrop for how the most recent course in Knowledge Management (spring of 2017) was conducted. The course is 7,5 ECTS and the students are primarily adults in a worklife. The course is net and seminar based, with three seminars per semester. During the seminars the concept of Flipped Classroom is used. This means that the students are provided with a recorded lecture in beforehand and only highlights are presented. The rest of the time during the seminar is used to activate the students through tasks and problem solving. However, the tasks are not predefined and prefabricated. The way this course is structured, the students themselves are giving the input to the tasks and assignments. This is based on the idea that the students themselves, coming from a worklife where knowledge management is a part of their every day worklife, should reflect upon their own practice. Also, it is important to share knowledge and by utilizing each students own experiences it is possible to enrich the “database” of cases or tasks for the students to solve and work with in order to incorporate the new theory from the course curriculum. Basing the problem solving on student input provide the lecturer AND the students with a richer knowledge base and case portfolio. This does, however, require some effort from the lecturers side. The input from the students are generally key words and fragments. The session is facilitated by the lecturer, encouraging the students to bring forward own experiences or situations they would like resolved, either real or fiction. The key words and fragments are discussed amongst the students and the lecturer makes notes on a blackboard or on a digital canvas (MS PowerPoint or similar). The students are given a break and the lecturer collects the key words and synthesizes this into a case. Upon the return of the stude...
Wan, Y, He, XS & Luo, X 2017, 'A Comparison of Modified Evolutionary Computation Algorithms with Applications to Three-Dimensional Endoscopic Camera Motion Tracking', Proceedings of the 2017 IEEE International Conference on Image Processing (ICIP), IEEE International Conference on Image Processing, IEEE, Beijing, pp. 3840-3843.
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Endoscope 3D motion tracking plays an irreplaceable role for computer-assisted endoscopy systems development. Without such tracking, it is impossible to synchronize pre- and intraoperative images in a reference coordinate frame. Currently available methods are comprised of video-based and electromagnetic tracking. These methods limit to either video image artifacts or inaccurate sensor measurements and dynamic errors. This paper proposes two modified evolutionary computation algorithms: (a) adaptive particle swarm optimization (APSO) and (b) observation-boosted differential evolution (OBDE), to augment current endoscopic camera motion tracking. The experimental results demonstrate that our modified algorithms, which combine endoscopic video images with sensor measurements to estimate endoscope movements, can improve tracking accuracy from 4.8 mm to 2.9 mm. OBDE outperforms APSO for endoscope tracking.
Wang, D, Geng, J, Jin, R, Xianling, L, Zhu, W, Wang, X, Ren, C & Ziolkowski, R 2017, 'A surface plasmon polariton inspired patch antenna', 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings, IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, San Diego, CA, USA, pp. 2499-2500.
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© 2017 IEEE. A patch antenna augmented with a magnetic surface plasmon polariton (SPP) spiral is proposed. It is fed by a small loop antenna. The final prototype of the optimized antenna has an overall size of 80 mm × 80 mm × 1 mm. Simulation results show that it has three working frequency bands; the -10 dB impedance bandwidth of each is: 1.99-2.52 GHz, 3.22-4.26 GHz and 4.71-5.16 GHz. These three working frequency bands all have field distributions characteristic of a scatterer with an excited, localized SPP mode. The peak gain achieved by this antenna is 6.5 dB.
Wang, H, Dutkiewicz, E, Jayawickrama, BA & Mueck, MD 2017, 'Design of Contour Based Protection Zones for Sublicensing in Spectrum Access Systems', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, 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 2017, 'Detection of contour boundary for sublicensing in spectrum access systems', 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, 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, Nguyen, D, Dutkiewicz & Mueck 2017, 'Game Theoretic Analysis of Sublicensing for PAL and GAA Bands in Spectrum Access System', 28th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (IEEE PIMRC 2017), IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, IEEE, Montreal, QC, Canada.
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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 noncooperative 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, J, Huang, S, Zhao, L, Ge, X, He, X, Zhang, C & Wang, X 2017, 'High Quality 3D Reconstruction of Indoor Environments using RGB-D Sensors', Proceedings of the 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), IEEE 12th Conference on Industrial Electronics and Applications (ICIEA), IEEE, Siem Reap, Cambodia, pp. 1736-1741.
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High-quality 3D reconstruction of large-scale indoor scene is the key to combine Simultaneous Localization And Mapping (SLAM) with other applications, such as building inspection and construction monitoring. However, the requirement of global consistency brings challenges to both localization and mapping. In particular, significant localization and mapping error can happen when standard SLAM techniques are used when dealing with the area of featureless walls and roofs. This paper proposed a novel framework aiming to reconstruct a high-quality, globally consistent 3D model for indoor environments using only a RGB-D sensor. We first introduce the sparse and dense feature constraints in the local bundle adjustment. Then, the planar constraints are incorporated in the global bundle adjustment. We fuse the point clouds in a truncated signed distance function volume, from which the high quality mesh can be extracted. Our framework leads to a comprehensive 3D scanning solution for indoor scene, enabling high-quality results and potential applications in building information system. The video of 3D models reconstructed by the method proposed in this paper is available at https://youtu.be/DWMP4YfeNeY.
Wang, Q & Huang, X 2017, 'Dimming Compatible Optical OFDM for High Speed Visible Light Communications', Proceedings of the 85th IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, Australia, pp. 1-4.
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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, Z & Piccardi, M 2017, '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 2017, 'Steganographic authentication in cloud storage for mitigation of security risks', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, International Conference on Systems Engineering, 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 2017, 'Steganographic image sharing app', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, 2017 25th International Conference on Systems Engineering, 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.
Wong, H, Lin, W, Wang, X & Lu, M 2017, 'LP and CP polarization reconfigurable antennas for modern wireless applications', 2017 International Symposium on Antennas and Propagation, ISAP 2017, pp. 1-2.
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© 2017 IEEE. This paper will present a series of novel polarization reconfigurable antennas for modern wireless applications. First, three multi-linear polarization reconfigurable antennas with the switchable 0°, +45°, 90° and-45° polarizations are investigated for mitigating the polarization mismatching problem in wireless biomedical applications. Three distinctive techniques were adopted to realize the same reconfigurability but with different radiation performance. In the beginning, a multi-dipole structure was designed. Four switchable half-wavelength dipoles were arranged in a compact structure and fed by a same source. Later, we used the slot antenna as the basic radiating element to realize the same polarization reconfigurability but with the improved directivity. Furthermore, to reduce the profile of the previously proposed two designs, a multiple L-probes fed circular patch antenna was designed. The profile was significantly decreased but the gain was improved. Second, three circular polarization reconfigurable antennas are introduced for increasing the channel capacity in satellite applications. Initially, a wideband CP reconfigurable antenna with conical-beam pattern was realized at the first time. Later on, two wideband broadside CP reconfigurable antennas were designed. The achieved bandwidth of our proposed antennas are widest among all the previously reported works.
Wong, SW, Lin, JY, Guo, ZC & Yang, Y 2017, 'Flexible control of transmission zeros using doublet for cavity bandpass filter design', 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, IEEE, Cairns, QLD, Australia, pp. 1-5.
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© 2017 IEEE. A variety of multiple-mode narrow-band bandpasss filer is designed, analyzed, and fabricated based on doublet and its properties. Three resonant modes: TE101, TE011and TM110 modes in a single cavity are excited. The proposed filters use a microstrip line as a feeder then couple to a slot on one side of a single rectangular cavity. By rotating and offsetting two slots at the input port and output port of the rectangular cavity, three fundamental modes are implemented without any cross-coupling. The proposed structure also create two transmission zeros (TZs), by adjusting the positions of the two TZs near the passband, e.g., at lower or upper stopband, high rejection is achieved. Due to emergence of the three resonant modes and realization of a pair of TZs, a high attenuation and sharp filtering selectivity is achieved. Good agreement between measurement and simulation is achieved.
Wu, G, Liu, RP, Ni, W & Xu, P 2017, 'Modeling CCH Switch to SCH in IEEE 802.11p/WAVE Vehicular Networks', IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, 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, W, Liu, RP, Ni, W, Kaafar, D & Huang, X 2017, 'AC-PROT: An Access Control Model to Improve Software-Defined Networking Security', Proceedings of the 85th IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, Australia, pp. 1-5.
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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, XS 2017, 'Deformable Template Matching Using Proposal-Based Best-Buddies Similarity', 2017 IEEE Trustcom/BigDataSE/ICESS, IEEE International Conference On Trust, Security And Privacy In Computing And Communications, IEEE, Sydney, pp. 517-521.
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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 conducted on a challenging dataset demonstrate that our method out-performs the state-of-the-art methods in terms of accuracy.
Xin, JN, Du, X & Zhang, J 2017, 'Deep learning for robust outdoor vehicle visual tracking', Proceedings - IEEE International Conference on Multimedia and Expo, IEEE International Conference on Multimedia and Expo, 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.
Yang, X, Ma, C, Wang, F, Jin, D & Xi, P 2017, 'Long-term ultra-low-level power STED nanoscopy', Optics InfoBase Conference Papers.
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© 2017 OSA. Through the strategic application of upconversion rare-earth nanoparticles (UCNPs), this work has reduced the intensity of the traditional super-resolution by 2-3 orders of magnitude. It reveals a new mechanism of stimulated emission caused by the photon avalanche effect. With only 30mW continuous laser, resolution down to 28nm has been attained, which is only 1/36 of the excitation wavelength.
Yang, Y, Zhu, X & Xue, Q 2017, 'On-Chip Circuit Miniaturization Techniques for Millimeter-Wave Bandpass Filter Design (Invited Paper)', Proceedings of the 10th Global Symposium on Millimeter-Waves (GSMM 2017), Global Symposium on Millimeter-Waves, IEEE, Hong Kong, pp. 24-27.
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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 mm 2 , competitive insertion loss (1 dB in GaAs BPF) and harmonic suppression of more than 44 dB.
Yao, L, Kusakunniran, W, Wu, Q, Zhang, J & Tang, Z 2017, 'Robust Gait Recognition under Unconstrained Environments using Hybrid Descriptions', Proceedings of the 2017 International Conference on Digital Image Computing: Techniques and Applications (DICTA), International Conference on Digital Image Computing: Techniques and Applications, IEEE, Sydney, Australia.
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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.
Yu, Z, Chaczko, Z & Jiang, J 2017, 'Development and optimization of wireless indoor localization error modelling', Proceedings - 25th International Conference on Systems Engineering, ICSEng 2017, 2017 25th International Conference on Systems Engineering, IEEE, Las Vegas, NV, USA, pp. 475-479.
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© 2017 IEEE. This paper introduces a new generation an error modelling of wireless indoor localization. A newly designed algorithm modelling by using Kalman Filter is developed to optimize the wireless indoor localization system based on iBeacon sensors. It is designed to detect and minimize the errors. Matlab simulations, implementation, and validation are presented in the paper.
Zha, X, Wang, X, Ni, W, Liu, RP, Guo, YJ, Niu, X & Zheng, K 2017, 'Analytic model on data security in VANETs', Proceedings of the 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, 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.
Zhang, H, Huang, X & Guo, YJ 2017, 'A 20 Gbps Digital Modem for High Speed Wireless Backhaul Applications', IEEE 85th Vehicular Technology Conference, IEEE.
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Zhang, J, Cantoni, A, Huang, X, Guo, Y & Heath, R 2017, 'Framework for an Innovative Perceptive Mobile Network Using Joint Communication and Sensing', 2017 IEEE 85th Vehicular Technology Conference (VTC Spring), 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, and supports new applications widely in transportation, surveillance and environmental sensing. Three types of sensing methods implemented in the base-stations are proposed, using either uplink or downlink multiuser communication signals. The required changes to system hardware and major technical challenges are briefly discussed. We also demonstrate the feasibility of estimating sensing parameters via developing a compressive sensing based scheme and providing simulation results to validate its effectiveness.
Zhang, J, Cantoni, A, Huang, X, Guo, Y & Heath, R 2017, 'Joint Communications and Sensing Using Two Steerable Analog Antenna Arrays', Proceedings of the 85th IEEE Vehicular Technology Conference (VTC Spring), IEEE, IEEE, Sydney, Australia.
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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, LI, H, Huang, X, Guo, YJ & Cantoni, A 2017, 'User-Directed Analog Beamforming for Multiuser Millimeter-Wave Hybrid Array Systems', Proceedings of the 85th IEEE Vehicular Technology Conference, IEEE Vehicular Technology Conference, IEEE, Sydney, Australia, pp. 1-5.
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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, W, Szymanski, J, Chiu, C, Chaczko, Z, Su, S & Zhou, J 2017, '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.
Zhao, M, Zhang, J, Porikli, F, Zhang, C & Zhang, W 2017, 'Learning a perspective-embedded deconvolution network for crowd counting', 2017 IEEE International Conference on Multimedia and Expo (ICME), IEEE International Conference on Multimedia and Expo, 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, M, Zhang, J, Porikli, F, Zhang, C & Zhang, W 2017, 'Learning a perspective-embedded deconvolution network for crowd counting', IEEE International Conference on Multimedia and Expo (ICME) 2017.
Zhong, Y, Zhu, JB, Dutkiewicz, E, Jiang, T & Zhou, Z 2017, 'Device-free sensing for classification of human activities using high-order cumulant algorithm', Proceedings of the 2017 17th International Symposium on Communications and Information Technologies, ISCIT 2017, International Symposium on Communications and Information Technologies, IEEE, Cairns, QLD, Australia, pp. 1-4.
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© 2017 IEEE. In this paper, the possibility of using an emerging approach, namely device-free sensing (DFS) technology, for classification of human activities is investigated. To fully evaluate this approach, several samples have been collected in an outdoor open-field environment. Using the collected data along with a classifier, a high-order cumulant (HOC) based feature extraction algorithm is investigated. To demonstrate the improvement of using this algorithm, the classical approach that is based on received-signal strength (RSS) is chosen as a benchmark. The experiment results demonstrated that the classification accuracy of the proposed algorithm is better than the classical approach by at least 15%. In addition, the reliability of the presented approach due to variation of training samples and signal-to-noise ratio (SNR) are also carefully tested using experimentally recorded samples, so that a good reliability can be ensured.
Zhu, X, Li, L, Zhang, W, Rao, Xu, M, Huang, Q & Xu, D 2017, 'Dependency Exploitation: A Unified CNN-RNN Approach for Visual Emotion Recognition', Proceedings of the Twenty-Sixth International Joint Conference on Artificial Intelligence (IJCAI-17), 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 CNNRNN
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 within 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 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.
Ziolkowski, RW 2017, '1987 IEEE AP Distinguished Achievement Awardee, Prof. Georges A. Deschamps, A True Gentleman and Distinguished Scholar', 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. 653-654.
Ziolkowski, RW & Tang, MC 2017, 'Overcoming traditional electrically small antenna tradeoffs with meta-structures', 2017 11th European Conference on Antennas and Propagation, EUCAP 2017, European Conference on Antennas and Propagation, IEEE, Paris, France, pp. 735-738.
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© 2017 Euraap. Metamaterial-inspired near-field resonant parasitic (NFRP) electrically small antennas (ESAs) have been designed and experimentally validated to have not only high radiation efficiencies, but also multi-functionality, large bandwidths, high directivities and reconfigurability. These expanded capabilities have been attained by introducing more complex meta-structures, i.e., multiple NFRP elements loaded with fixed and tunable lumped elements, as well as active circuits. Different classes of passive and active NFRP ESAs that have successfully produced these effects will be reviewed, and several recently reported ESA systems will be introduced and discussed.
Zuo, Y, Wu, Q & Zhang, J 2017, 'Minimum spanning forest with embedded edge inconsistency measurement for color-guided depth map upsampling', 2017 IEEE International Conference on Multimedia and Expo, IEEE, Hong Kong, China.
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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.