Abeywickrama, HV, Jayawickrama, BA, He, Y & Dutkiewicz, E 2018, 'Comprehensive Energy Consumption Model for Unmanned Aerial Vehicles, Based on Empirical Studies of Battery Performance', IEEE Access, vol. 6, pp. 58383-58394.
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© 2018 IEEE. Unmanned aerial vehicles (UAVs) are fast gaining popularity in a wide variety of areas and are already being used for a range of tasks. Despite their many desirable features, a number of drawbacks hinder the potential of UAV applications. As typical UAVs are powered by on-board batteries, limited battery lifetime is identified as a key limitation in UAV applications. Thus, in order to preserve the available energy, planning UAV missions in an energy efficient manner is of utmost importance. For energy efficient UAV mission planning, it is necessary to predict the energy consumption of specific UAV manoeuvring actions. Accurate energy prediction requires a reliable and realistic energy consumption model. In this paper, we present a consistent and complete energy consumption model for UAVs based on empirical studies of battery usage for various UAV activities. We considered the impact of different flight scenarios and conditions on UAV energy consumption when developing the proposed model. The energy consumption model presented in this paper can be readily used for energy efficient UAV mission planning.
Abolhasan, M, Abdollahi, M, Ni, W, Jamalipour, A, Shariati, N & Lipman, J 2018, 'A Routing Framework for Offloading Traffic From Cellular Networks to SDN-Based Multi-Hop Device-to-Device Networks', IEEE Transactions on Network and Service Management, vol. 15, no. 4, pp. 1516-1531.
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© 2004-2012 IEEE. Device-to-device (D2D) communications are set to form an integral part of future 5G wireless networks. D2D communications have a number of benefits such as improving energy efficiency and spectrum utilization. Until now much of the D2D research in LTE and 5G-type network scenarios have focused on direct (one-hop) communications between two adjacent mobile devices. In this paper, we propose a new routing framework called virtual ad hoc routing protocol (VARP). This framework introduces significant advantages such as better security, lower routing overheads, and higher scalability, when compared to conventional ad hoc routing protocols. It also reduces traffic overhead in LTE networks using multi-hop D2D communications under management of a software defined networking (SDN)-controller. Further, it enables the development of various types of routing protocols for different networking scenarios. To this end, a source-routing based protocol was developed on top of VARP, referred to as VARP-S. We present a detailed analytical study of routing overhead in the VARP-S protocol, as compared to overhead analysis of our previous proposed hybrid SDN architecture for wireless distributed networks (HSAW) Our results show that VARP-S, compared to HSAW, achieves higher network scalability and lower power consumption for mobile nodes.
Aldebei, K, He, X, Jia, W & Yeh, W 2018, 'SUDMAD: Sequential and unsupervised decomposition of a multi‐author document based on a hidden markov model', Journal of the Association for Information Science and Technology, vol. 69, no. 2, pp. 201-214.
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Decomposing a document written by more than one author into sentences based on authorship is of great significance due to the increasing demand for plagiarism detection, forensic analysis, civil law (i.e., disputed copyright issues), and intelligence issues that involve disputed anonymous documents. Among existing studies for document decomposition, some were limited by specific languages, according to topics or restricted to a document of two authors, and their accuracies have big room for improvement. In this paper, we consider the contextual correlation hidden among sentences and propose an algorithm for Sequential and Unsupervised Decomposition of a Multi‐Author Document (SUDMAD) written in any language, disregarding topics, through the construction of a Hidden Markov Model (HMM) reflecting the authors' writing styles. To build and learn such a model, an unsupervised, statistical approach is first proposed to estimate the initial values of HMM parameters of a preliminary model, which does not require the availability of any information of author's or document's context other than how many authors contributed to writing the document. To further boost the performance of this approach, a boosted HMM learning procedure is proposed next, where the initial classification results are used to create labeled training data to learn a more accurate HMM. Moreover, the contextual relationship among sentences is further utilized to refine the classification results. Our proposed approach is empirically evaluated on three benchmark datasets that are widely used for authorship analysis of documents. Comparisons with recent state‐of‐the‐art approaches are also presented to demonstrate the significance of our new ideas and the superior performance of our approach.
Alzoubi, YI, Gill, AQ & Moulton, B 2018, 'A measurement model to analyze the effect of agile enterprise architecture on geographically distributed agile development.', J. Softw. Eng. Res. Dev., vol. 6, no. 4, pp. 4-4.
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Babar, A, Bunker, D & Qumer Gill, A 2018, 'Investigating the Relationship between Business Analysts’ Competency and IS Requirements Elicitation: A Thematic-analysis Approach', Communications of the Association for Information Systems, vol. 42, no. 1, pp. 334-362.
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© 2018 by the Association for Information Systems. Researchers and practitioners have consistently reported poor requirements elicitation (RE) as one of the major reasons for information system (IS) project failures. In the last two decades, RE research and practice have focused predominantly on developing tools and techniques for business analysts (BAs) to use and improve RE; however, they have paid little attention to the importance of the competency of the BAs involved in RE. We investigate the relationship between the BAs’ competency and RE through an exploratory study. We applied a thematic network analysis approach, along with a four-stage qualitative data-analysis process, to discover four business view and six system view themes and their relationships to BAs’ competency. Our results indicate that senior, intermediate, and junior BAs performed similarly in selecting stakeholders’ viewpoints and collecting requirements from them; however, senior BAs focused more on high-level requirements than the low-level technical requirements of the system. The results suggest that BAs’ competency play a significant role in RE and that organizations that clearly define BAs’ competency can help them to identify the right BA for the right job.
Bah, AO, Qin, P-Y, Ziolkowski, RW, Cheng, Q & Guo, YJ 2018, 'Realization of an Ultra-thin Metasurface to Facilitate Wide Bandwidth, Wide Angle Beam Scanning', Scientific Reports, vol. 8, no. 1.
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AbstractA wide bandwidth, ultra-thin, metasurface is reported that facilitates wide angle beam scanning. Each unit cell of the metasurface contains a multi-resonant, strongly-coupled unequal arm Jerusalem cross element. This element consists of two bent-arm, orthogonal, capacitively loaded strips. The wide bandwidth of the metasurface is achieved by taking advantage of the strong coupling within and between its multi-resonant elements. A prototype of the proposed metasurface has been fabricated and measured. The design concept has been validated by the measured results. The proposed metasurface is able to alleviate the well-known problem of impedance mismatch caused by mutual coupling when the main beam of an array is scanned. In order to validate the wideband and wide scanning ability of the proposed metasurface, it is integrated with a wideband antenna array as a wide angle impedance matching element. The metasurface-array combination facilitates wide angle scanning over a 6:1 impedance bandwidth without the need for bulky dielectrics or multi-layered structures.
Bargi, A, Xu, RYD & Piccardi, M 2018, 'AdOn HDP-HMM: An Adaptive Online Model for Segmentation and Classification of Sequential Data', IEEE Transactions on Neural Networks and Learning Systems, vol. 29, no. 9, pp. 3953-3968.
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© 2012 IEEE. Recent years have witnessed an increasing need for the automated classification of sequential data, such as activities of daily living, social media interactions, financial series, and others. With the continuous flow of new data, it is critical to classify the observations on-the-fly and without being limited by a predetermined number of classes. In addition, a model should be able to update its parameters in response to a possible evolution in the distributions of the classes. This compelling problem, however, does not seem to have been adequately addressed in the literature, since most studies focus on offline classification over predefined class sets. In this paper, we present a principled solution for this problem based on an adaptive online system leveraging Markov switching models and hierarchical Dirichlet process priors. This adaptive online approach is capable of classifying the sequential data over an unlimited number of classes while meeting the memory and delay constraints typical of streaming contexts. In this paper, we introduce an adaptive 'learning rate' that is responsible for balancing the extent to which the model retains its previous parameters or adapts to new observations. Experimental results on stationary and evolving synthetic data and two video data sets, TUM Assistive Kitchen and collated Weizmann, show a remarkable performance in terms of segmentation and classification, particularly for sequences from evolutionary distributions and/or those containing previously unseen classes.
Bowden, R & Veitch, D 2018, 'Finding the Right Tree: Topology Inference Despite Spatial Dependences', IEEE Transactions on Information Theory, vol. 64, no. 6, pp. 4594-4609.
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© 1963-2012 IEEE. Network tomographic techniques have almost exclusively been built on a strong assumption of mutual independence of link processes. We introduce model classes for link loss processes with non-Trivial spatial dependencies, for which the tree topology is nonetheless identifiable from leaf measurements using multicast probing. We show that these classes are large in a well-defined sense, and we provide an algorithm, SLTD, capable of returning the correct topology with certainty in the limit of infinite data.
Chen, S-L, Qin, P-Y, Lin, W & Guo, YJ 2018, 'Pattern-Reconfigurable Antenna With Five Switchable Beams in Elevation Plane', IEEE Antennas and Wireless Propagation Letters, vol. 17, no. 3, pp. 454-457.
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© 2017 IEEE. Pattern-reconfigurable antennas with multiple switchable beams, especially with both boresight and endfire directions, are highly desired for wireless communications. In this letter, a novel pattern-reconfigurable antenna is proposed that provides an efficient solution. By reconfiguring parasitic striplines placed around a radiating dipole and reflecting metal pieces under the dipole using p-i-n diodes, the antenna main beam can be switched to five directions in the elevation plane, approximately from-90(left endfire),-45 , 0 (boresight),+45 to +90(right endfire). The proposed antenna operates at 2.45 GHz with dimensions of about 0.57λ× 0.45\lambda×, 0.28λ. An antenna prototype is fabricated and measured. For all five directional beams, the measured S-{11}| values are below 13 dB, and the measured realized gains range from 5.2 to 6.5 dBi. They agree reasonably well with the simulated ones.
Cheng, P, Chen, Z, Zhang, JA, Li, Y & Vucetic, B 2018, 'A Unified Precoding Scheme for Generalized Spatial Modulation', IEEE Transactions on Communications, vol. 66, no. 6, pp. 2502-2514.
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© 1972-2012 IEEE. Generalized spatial modulation (GSM) activates Nt (1 ≤ nt < Nt) available transmit antennas, and information is conveyed through nt modulated symbols as well as the index of the nt activated antennas. GSM strikes an attractive tradeoff between spectrum efficiency and energy efficiency. Linear precoding that exploits channel state information at the transmitter enhances the system error performance. For GSM with nt=1 (the traditional SM), the existing precoding methods suffer from high computational complexity. On the other hand, GSM precoding for nt ≥ 2 is not thoroughly investigated in the open literature. In this paper, we develop a unified precoding design for GSM systems, which universally works for all nt values. Based on the maximum minimum Euclidean distance criterion, we find that the precoding design can be formulated as a large-scale nonconvex quadratically constrained quadratic program problem. Then, we transform this challenging problem into a sequence of unconstrained subproblems by leveraging augmented Lagrangian and dual ascent techniques. These subproblems can be solved in an iterative manner efficiently. Numerical results show that the proposed method can substantially improve the system error performance relative to the GSM without precoding and features extremely fast convergence rate with a very low computational complexity.
Cui, Q, Gu, Y, Ni, W, Zhang, X, Tao, X, Zhang, P & Liu, RP 2018, 'Preserving Reliability of Heterogeneous Ultra-Dense Distributed Networks in Unlicensed Spectrum', IEEE Communications Magazine, vol. 56, no. 6, pp. 72-78.
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© 1979-2012 IEEE. This article investigates the prominent dilemma between capacity and reliability in heterogeneous ultra-dense distributed networks, and advocates a new measure of effective capacity to quantify the maximum sustainable data rate of a link while preserving the quality of service of the link in such networks. Recent breakthroughs are brought forth in developing the theory of the effective capacity in heterogeneous ultra-dense distributed networks. Potential applications of the effective capacity are demonstrated on the admission control, power control, and resource allocation of such networks, with substantial gains revealed over existing technologies. This new measure is of particular interest to ultra-dense deployment of the emerging 5G wireless networks in the unlicensed spectrum, leveraging the capacity gain brought by the use of the unlicensed band and the stringent reliability sustained by 5G in future heterogeneous network environments.
Ding, C, Sun, H-H, Ziolkowski, RW & Jay Guo, Y 2018, 'A Dual Layered Loop Array Antenna for Base Stations With Enhanced Cross-Polarization Discrimination', IEEE Transactions on Antennas and Propagation, vol. 66, no. 12, pp. 6975-6985.
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© 1963-2012 IEEE. This paper presents a novel dual-loop array antenna targeted at current and future base station applications. The antenna has four rectangular loops and four trapezoidal loops printed on the front and back sides, respectively, of a substrate placed above a flat square reflector. All eight loop radiators are excited simultaneously with properly designed feed networks to achieve its ±45° polarization states. The trapezoidal loops act like folded (electric) dipoles; the rectangular loops act primarily as magnetic dipoles. The combination of these two loop arrays leads to a type of magnetoelectric loop antenna that has stable directivity patterns with high cross-polarization discrimination (XPD) values across a 45.5% operational fractional bandwidth from 1.7 to 2.7 GHz. A fabricated and measured prototype confirms the simulation results and demonstrates that the half-power beamwidths in the horizontal plane vary between 63° and 70°, the XPD values are >20 dB in the boresight direction, and are >10 dB within the entire cellular coverage angular range:-60 θ 60°.
Esmaili, N, Piccardi, M, Kruger, B & Girosi, F 2018, 'Analysis of healthcare service utilization after transport-related injuries by a mixture of hidden Markov models', PLOS ONE, vol. 13, no. 11, pp. e0206274-e0206274.
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© 2018 Esmaili et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background Transport injuries commonly result in significant disease burden, leading to physical disability, mental health deterioration and reduced quality of life. Analyzing the patterns of healthcare service utilization after transport injuries can provide an insight into the health of the affected parties, allow improved health system resource planning, and provide a baseline against which any future system-level interventions can be evaluated. Therefore, this research aims to use time series of service utilization provided by a compensation agency to identify groups of claimants with similar utilization patterns, describe such patterns, and characterize the groups in terms of demographic, accident type and injury type. Methods To achieve this aim, we have proposed an analytical framework that utilizes latent variables to describe the utilization patterns over time and group the claimants into clusters based on their service utilization time series. To perform the clustering without dismissing the temporal dimension of the time series, we have used a well-established statistical approach known as the mixture of hidden Markov models (MHMM). Ensuing the clustering, we have applied multinomial logistic regression to provide a description of the clusters against demographic, injury and accident covariates. Results We have tested our model with data on psychology service utilization from one of the main compensation agencies for transport accidents in Australia, and found that three clear clusters of service utilization can be evinced from the data. These three clusters correspond to claimants who have tended to use the services 1) only briefly after the accident; 2) for an intermediate period of time...
Feng, X, Wan, W, Xu, RYD, Chen, H, Li, P & Sánchez, JA 2018, 'A perceptual quality metric for 3D triangle meshes based on spatial pooling', Frontiers of Computer Science, vol. 12, no. 4, pp. 798-812.
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Feng, X, Wan, W, Xu, RYD, Perry, S, Zhu, S & Liu, Z 2018, 'A new mesh visual quality metric using saliency weighting-based pooling strategy', Graphical Models, vol. 99, pp. 1-12.
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© 2018 Elsevier Inc. Several metrics have been proposed to assess the visual quality of 3D triangular meshes during the last decade. In this paper, we propose a mesh visual quality metric by integrating mesh saliency into mesh visual quality assessment. We use the Tensor-based Perceptual Distance Measure metric to estimate the local distortions for the mesh, and pool local distortions into a quality score using a saliency weighting-based pooling strategy. Three well-known mesh saliency detection methods are used to demonstrate the superiority and effectiveness of our metric. Experimental results show that our metric with any of three saliency maps performs better than state-of-the-art metrics on the LIRIS/EPFL general-purpose database. We generate a synthetic saliency map by assembling salient regions from individual saliency maps. Experimental results reveal that the synthetic saliency map achieves better performance than individual saliency maps, and the performance gain is closely correlated with the similarity between the individual saliency maps.
Feng, X, Wan, W, Yi Da Xu, R, Perry, S, Li, P & Zhu, S 2018, 'A novel spatial pooling method for 3D mesh quality assessment based on percentile weighting strategy', Computers & Graphics, vol. 74, pp. 12-22.
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Gao, X, Zhang, T, Du, J & Guo, YJ 2018, 'Design, modelling and simulation of a monolithic high-T c superconducting terahertz mixer', Superconductor Science and Technology, vol. 31, no. 11, pp. 115010-115010.
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© 2018 IOP Publishing Ltd. This paper presents a novel concept and design of a full monolithic integrated high-T c superconducting (HTS) Josephson junction terahertz (THz) harmonic mixer coupled with a circularly polarized (CP) antenna. The fully on-chip mixer device is very compact in size and utilizes the CP antenna to enhance the polarization orientation flexibility in coupling THz radiation. Electromagnetic simulations are carried out to optimize the coupling efficiency and axial ratio of the THz CP antenna, and the signal transmission and isolation characteristics of the monolithic circuit. An equivalent circuit model of the HTS THz mixer is then established and simulation is performed based on our previously measured step-edge Josephson junction characteristics to evaluate the device performance and validate the concept of design. The results show that a superior performance could be achieved from such a monolithic HTS mixer device, which is significantly better than any HTS THz harmonic mixers reported to date.
Guo, J, Yang, T, Yuan, J & Zhang, JA 2018, 'A Novel Linear Physical-Layer Network Coding Scheme for Y-Channel Without Transmitter CSI', IEEE Transactions on Vehicular Technology, vol. 67, no. 10, pp. 10049-10053.
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© 1967-2012 IEEE. We propose a novel linear physical-layer network coding (NC) scheme for a fading Y-channel without channel state information at transmitters. In this three-user scheme, each user intends to realize a full data exchange with the other two users via a relay. Instead of directly decoding the users' messages from the received signal, the relay determines NC generator matrices and reconstructs linear NC codewords from its received signals to facilitate the information exchange. We present an explicit solution for NC generator matrices that minimize the NC error probability at high SNRs. We also present and prove an approximation of the NC error probability of the proposed scheme at high SNRs. Numerical results show that the proposed scheme outperforms existing ones, and its performance can be well characterized by the approximation.
Guo, J, Yuan, J & Zhang, J 2018, 'An Achievable Throughput Scaling Law of Wireless Device-to-Device Caching Networks With Distributed MIMO and Hierarchical Cooperations', IEEE Transactions on Wireless Communications, vol. 17, no. 1, pp. 492-505.
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© 2002-2012 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 neighbors 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 neighbors. 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. Furthermore, we derive an explicit expression of the optimal throughput as a function of system parameters, such as pathloss factor under a target outage probability. Analytical and numerical results demonstrate that our proposed scheme outperforms existing ones when the local cache size is limited.
Guo, YJ, Qin, P-Y, Chen, S-L, Lin, W & Ziolkowski, RW 2018, 'Advances in Reconfigurable Antenna Systems Facilitated by Innovative Technologies', IEEE Access, vol. 6, pp. 5780-5794.
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© 2013 IEEE. Future fifth generation (5G) wireless platforms will require reconfigurable antenna systems to meet their performance requirements in compact, light-weight, and cost-effective packages. Recent advances in reconfigurable radiating and receiving structures have been enabled by a variety of innovative technology solutions. Examples of reconfigurable partially reflective surface antennas, reconfigurable filtennas, reconfigurable Huygens dipole antennas, and reconfigurable feeding network-enabled antennas are presented and discussed. They represent novel classes of frequency, pattern, polarization, and beam-direction reconfigurable systems realized by the innovative combinations of radiating structures and circuit components.
Han, L, Liu, S, Han, S, Jia, W & Lei, J 2018, 'Owner based malware discrimination', Future Generation Computer Systems, vol. 80, pp. 496-504.
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© 2016 Elsevier B.V. A piece of malware code can be harmful in one's system but totally harmless in another's. In this paper, we point out that the detection of malicious code or software is actually a matter of discrimination which depends on the owners of the computer systems. We propose an owner based malicious software discrimination model, named as Unlimited Register Machine of Owners (URMO). First, we characterize and analyze the limitations of existing discrimination techniques in theory by using the discrimination model of Unlimited Register Machine (URM) and then move on to construct the URMO discrimination model by giving the two important elements of malicious behavior: an operation and the object of the operation. The relationship between an operation and the object of the operation is fundamental to solving the relativity of the discrimination problem about malice, which is also the advantage of the URMO model. Finally, by applying the model to discriminate real-world malware and comparing it with existing popular antivirus software, we demonstrate the effectiveness and superior performance of the URMO model.
He, Y, Jayawickrama, BA, Dutkiewicz, E, Srikanteswara, S & Mueck, M 2018, 'Priority Access and General Authorized Access Interference Mitigation in the Spectrum Access System', IEEE Transactions on Vehicular Technology, vol. 67, no. 6, pp. 4969-4983.
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© 1967-2012 IEEE. To meet the capacity needs of next generation wireless communications, the U.S. Federal Communications Commission has recently introduced the spectrum access system. Spectrum is shared between three tiers - incumbents, priority access licensees (PAL), and general authorized access (GAA) licensees. When the incumbents are absent, PAL and GAA share the spectrum under the constraint that GAA ensure the interference to PAL is no more than $-$40 dBm with at least 99% confidence. We consider the scenario where locations are not shared between PAL and GAA. We propose a PAL-GAA cochannel interference mitigation technique that does not expose base station locations. Our approach relies on GAA sharing the distribution and maximum number of transmitters in a finite area. We show how PAL can derive the distribution of the aggregate interference using the probability density function and characteristic function, and notify GAA about the exclusion zones in space that will guarantee that the interference requirement is met. We also propose a numerical approximation using inverse fast Fourier and discrete Fourier transforms. Analytically calculated distribution aligns well with the numerical results. Additionally, we formulate an optimization problem for the optimal exclusion zone size. We analytically prove convexity of the problem. Our approach reduces the exclusion zone size by over 42%, which gives significantly more spectral opportunities to GAA in the spatial domain.
Hoang, DT, Niyato, D, Nguyen, DN, Dutkiewicz, E, Wang, P & Han, Z 2018, 'A Dynamic Edge Caching Framework for Mobile 5G Networks', IEEE Wireless Communications, vol. 25, no. 5, pp. 95-103.
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© 2002-2012 IEEE. Mobile edge caching has emerged as a new paradigm to provide computing, networking resources, and storage for a variety of mobile applications. That helps achieve low latency, high reliability, and improve efficiency in handling a very large number of smart devices and emerging services (e.g., IoT, industry automation, virtual reality) in mobile 5G networks. Nonetheless, the development of mobile edge caching is challenged by the decentralized nature of edge nodes, their small coverage, limited computing, and storage resources. In this article, we first give an overview of mobile edge caching in 5G networks. After that, its key challenges and current approaches are discussed. We then propose a novel caching framework. Our framework allows an edge node to authorize the legitimate users and dynamically predicts and updates their content demands using the matrix factorization technique. Based on the prediction, the edge node can adopt advanced optimization methods to determine optimal content to store so as to maximize its revenue and minimize the average delay of its mobile users. Through numerical results, we demonstrate that our proposed framework provides not only an effective caching approach, but also an efficient economic solution for the mobile service provider.
Hou, ZJ, Yang, Y, Chiu, L, Zhu, X & Xue, Q 2018, 'Wideband Millimeter-Wave On-Chip Quadrature Coupler With Improved In-Band Flatness in 0.13-<inline-formula> <tex-math notation='LaTeX'>$\mu$ </tex-math> </inline-formula>m SiGe Technology', IEEE Electron Device Letters, vol. 39, no. 5, pp. 652-655.
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© 1980-2012 IEEE. This letter proposes a compact and broadband quadrature coupler with a center frequency of 55 GHz, which consists of a 90° broadside coupled-line to support the differential signal propagation and two T-type L-C networks to support the common signal propagation. To analyze the proposed coupler, an equivalent circuit model is provided for estimation of the distributed and lumped component values. The measured results of the proposed on-chip quadrature coupler show that the return loss and isolation are greater than 20 dB with a bandwidth of 105%, while the insertion loss is about -0.85 dB. The magnitude imbalances are less than 1 dB within the bandwidth of 56% and the phase differences are with ±1° errors within the bandwidth of 96.9%. The chip size, excluding the test pads, is only 0.31 × 0.22 mm2.
Hou, ZJ, Yang, Y, Chiu, L, Zhu, X, Dutkiewicz, E, Vardaxoglou, JC & Xue, Q 2018, 'A W-Band Balanced Power Amplifier Using Broadside Coupled Strip-Line Coupler in SiGe BiCMOS 0.13-<inline-formula> <tex-math notation='LaTeX'>$\mu\text{m}$ </tex-math> </inline-formula> Technology', IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 65, no. 7, pp. 2139-2150.
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© 2004-2012 IEEE. Load-variation insensitivity, for impedance matching between power amplifiers (PAs) and transmitting antennas, contributes to challenging the design of millimeter-wave wireless systems. In this paper, a W -band two-way balanced PA based on a compact quadrature coupler with a broadside coupled strip-line (BCSL) as the core is presented to enhance the load-variation insensitivity and stability. The proposed coupler is truly broadband with low amplitude and phase imbalance. The proposed W -band balanced PA achieves higher power-added efficiency (PAE) and unsaturated output power {P} -{\mathrm{ sat}} over wide frequency bandwidth. The W -band balanced PA is implemented in a 0.13- \mu \text{m} SiGe BiCMOS process and achieves a measured {P} -{\mathrm{ sat}} of 16.3 dBm and a peak PAE of 14.1% at 100 GHz (with 1.6-V power supply). The measured {P} -{\mathrm{ sat}} with 1-dB bandwidth is from 91 to 102 GHz. The measured results present the feasibility of the compact quadrature coupler. The total chip surface area (with pads) is 0.64 mm2, where the size of the proposed quadrature coupler area is only 0.04 mm2.
Hou, ZJ, Yang, Y, Zhu, X, Li, YC, Dutkiewicz, E & Xue, Q 2018, 'A Compact and Low-Loss Bandpass Filter Using Self-Coupled Folded-Line Resonator With Capacitive Feeding Technique', IEEE Electron Device Letters, vol. 39, no. 10, pp. 1-1.
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© 1980-2012 IEEE. This letter proposes a compact and low-loss on-chip bandpass filter (BPF) design in (Bi)-CMOS technology. The proposed BPF consists of a self-coupled folded-line resonator and a pair of metal-insulator-metal capacitors. The proposed resonator has a property of flexible self-resonant frequency to form a transmission zero, which is analyzed in detail by a simplified LC equivalent circuit. Moreover, the parametric studies of the feeding capacitance for the proposed BPF design have been performed to demonstrate the tenability of the resonant frequency. For verification, the proposed BPF is fabricated in a standard 0.13-μ m (Bi)-CMOS technology. The measured results show that the proposed BPF has a notch with 25.4-dB suppression at 65 GHz and an insertion loss of 1.66 dB in the passband. The chip size of the device, excluding the test pads, is only 0.009 mm2 (0.11 × 0.086 mm2).
Huang, X, Zhang, J, Wu, Q, Fan, L & Yuan, C 2018, 'A Coarse-to-Fine Algorithm for Matching and Registration in 3D Cross-Source Point Clouds', IEEE Transactions on Circuits and Systems for Video Technology, vol. 28, no. 10, pp. 2965-2977.
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© 1991-2012 IEEE. We propose an efficient method to deal with the matching and registration problem found in cross-source point clouds captured by different types of sensors. This task is especially challenging due to the presence of density variation, scale difference, a large proportion of noise and outliers, missing data, and viewpoint variation. The proposed method has two stages: in the coarse matching stage, we use the ensemble of shape functions descriptor to select potential K regions from the candidate point clouds for the target. In the fine stage, we propose a scale embedded generative Gaussian mixture models registration method to refine the results from the coarse matching stage. Following the fine stage, both the best region and accurate camera pose relationships between the candidates and target are found. We conduct experiments in which we apply the method to two applications: one is 3D object detection and localization in street-view outdoor (LiDAR/VSFM) cross-source point clouds and the other is 3D scene matching and registration in indoor (KinectFusion/VSFM) cross-source point clouds. The experiment results show that the proposed method performs well when compared with the existing methods. It also shows that the proposed method is robust under various sensing techniques, such as LiDAR, Kinect, and RGB camera.
Huynh, NV, Hoang, DT, Nguyen, DN, Dutkiewicz, E, Niyato, D & Wang, P 2018, 'Optimal and Low-Complexity Dynamic Spectrum Access for RF-Powered Ambient Backscatter System with Online Reinforcement Learning', IEEE TRANSACTIONS ON COMMUNICATIONS, vol. 67, no. 8, pp. 5736-5752.
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Ambient backscatter has been introduced with a wide range of applications forlow power wireless communications. In this article, we propose an optimal andlow-complexity dynamic spectrum access framework for RF-powered ambientbackscatter system. In this system, the secondary transmitter not only harvestsenergy from ambient signals (from incumbent users), but also backscatters thesesignals to its receiver for data transmission. Under the dynamics of theambient signals, we first adopt the Markov decision process (MDP) framework toobtain the optimal policy for the secondary transmitter, aiming to maximize thesystem throughput. However, the MDP-based optimization requires completeknowledge of environment parameters, e.g., the probability of a channel to beidle and the probability of a successful packet transmission, that may not bepractical to obtain. To cope with such incomplete knowledge of the environment,we develop a low-complexity online reinforcement learning algorithm that allowsthe secondary transmitter to 'learn' from its decisions and then attain theoptimal policy. Simulation results show that the proposed learning algorithmnot only efficiently deals with the dynamics of the environment, but alsoimproves the average throughput up to 50% and reduces the blocking probabilityand delay up to 80% compared with conventional methods.
Huynh, NV, Hoang, DT, Niyato, D, Wang, P & Kim, DI 2018, 'Optimal Time Scheduling for Wireless-Powered Backscatter Communication Networks', IEEE Wireless Communications Letters, vol. 7, no. 5, pp. 820-823.
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This letter introduces a novel wireless-powered backscatter communicationsystem which allows sensors to utilize RF signals transmitted from a dedicatedRF energy source to transmit data. In the proposed system, when the RF energysource transmits RF signals, the sensors are able to backscatter the RF signalsto transmit date to the gateway and/or harvest energy from the RF signals fortheir operations. By integrating backscattering and energy harvestingtechniques, we can optimize the network throughput of the system. Inparticular, we first formulate the time scheduling problem for the system, andthen propose an optimal solution using convex optimization to maximize theoverall network throughput. Numerical results show a significant throughputgain achieved by our proposed design over two other baseline schemes.
Ismaiel, B, Abolhasan, M, Ni, W, Smith, DB, Franklin, DR & Jamalipour, A 2018, 'Analysis of Effective Capacity and Throughput of Polling-Based Device-To-Device Networks.', IEEE Trans. Veh. Technol., vol. 67, no. 9, pp. 8656-8666.
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© 1967-2012 IEEE. Next-generation wireless networks will give rise to heterogeneous networks by integrating multiple wireless access technologies to provide seamless mobility to mobile users with high-speed wireless connectivity. Device-to-device (D2D) communication has proven to be a promising technology that can increase the capacity and coverage of wireless networks. The D2D communication was first introduced in long-term evolution advanced (LTE-A) and has gained immense popularity for the offloading traffic using the licensed and unlicensed band. Challenges arise from resource allocation, provision of quality-of-service (QoS), and the quantification of capacity in an unlicensed band due to the distributed nature of Wi-Fi. In this paper, we propose an analytical performance model for the scalable MAC protocol (SC-MP) in which a resource allocation mechanism is based on the IEEE 802.11 point coordinated function to access the Wi-Fi channel for voice and video/multimedia traffic. In the SC-MP, D2D communication is applied to further offload the video/multimedia traffic. In particular, this paper establishes a three-state semi-Markovian model to derive a closed-form expression of effective capacity in terms of transmission rate and quality-of-service. Further, the SC-MP is analytically modeled using the four-state traditional Markov model to derive the saturation throughput. The analytical results are validated through simulations, hence, proving the appropriateness of the model.
Ismaiel, B, Abolhasan, M, Ni, W, Smith, DB, Franklin, DR, Dutkiewicz, E, Krunz, M & Jamalipour, A 2018, 'PCF-Based LTE Wi-Fi Aggregation for Coordinating and Offloading the Cellular Traffic to D2D Network.', IEEE Trans. Veh. Technol., vol. 67, no. 12, pp. 12193-12203.
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© 2018 IEEE. Device-to-device (D2D) communication is a promising technology towards 5G networks. D2D communication can offload traffic using licensed/unlicensed band by establishing a direct communication between two users without traversing the base station or core network. However, one of the major challenges of D2D communication is resource allocation and guaranteeing quality-of-service (QoS). In this paper, we establish an optimal queuing scheduling and resource allocation problem for three-tier heterogeneous network based on LTE Wi-Fi aggregation, to offload voice/multimedia traffic from licensed band to unlicensed band using scalable MAC protocol (SC-MP) under various static delay constraints. The access mechanism used for Wi-Fi in SC-MP is point coordination function, which further offloads the multimedia traffic using D2D communication in unlicensed band. Resource allocation and optimal joint queuing scheduling problems are formulated with diverse QoS guarantee between licensed and unlicensed band to minimize the bandwidth of licensed band. Furthermore, an iterative algorithm is proposed to express the nonconvex problem as a series of subproblems based on block coordinate descent and difference of two convex functions (D.C) program. We have simulated the proposed scheme using two scenarios: Voice traffic using licensed band and voice traffic using both licensed and unlicensed band, whereas multimedia traffic uses unlicensed band for both the scenarios. The simulation results show that both the schemes perform better than the existing scheme and scenario 2 outperforms scenario 1.
Jayawickrama, BA, He, Y, Dutkiewicz, E & Mueck, MD 2018, 'Scalable Spectrum Access System for Massive Machine Type Communication', IEEE Network, vol. 32, no. 3, pp. 154-160.
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© 1986-2012 IEEE. Future 5G networks aspire to enable new services with vastly different data rate, latency and scalability requirements. The consensus is that these new services will fall into three categories: eMBB, URLLC, and mMTC. Due to unique characteristics of these services and the limited availability of finite spectrum resources, 5G will need to carefully map appropriate bands and spectrum usage models for each service. The SAS is an emerging spectrum sharing model that is gaining momentum in the U.S. SAS presents an opportunity for operators to access the 3.5 GHz military radar band for commercial use. This article discusses the feasibility of the current SAS model in the context of mMTC. We propose a scalable SAS framework that can manage the mMTC uplink interference to the incumbent with less overhead. The simulation setup models the interference levels in New York City and its surrounding counties. The results show that mMTC uplink transmission can be enabled using our framework even on the coast of New York, where mMTC density is high, without causing a harmful level of interference to the incumbent.
Ji, L-Y, Qin, P-Y & Guo, YJ 2018, 'Wideband Fabry-Perot Cavity Antenna With a Shaped Ground Plane', IEEE Access, vol. 6, pp. 2291-2297.
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© 2013 IEEE. This paper proposes a novel approach to broaden the 3-dB gain bandwidth of Fabry-Perot cavity (FPC) antennas by utilizing a shaped ground plane. The shaped ground plane is flat in the middle to accommodate the source antenna, and then angled up in the shape of trapezoids. Compared with an FPC antenna with a traditional flat ground plane, the 3-dB gain bandwidth of the one with a shaped ground plane is improved from 11% to 20.2% with the maximum realized gain and the 10-dB impedance bandwidth almost unchanged. To validate the feasibility of the proposed approach, an FPC antenna prototype has been designed, fabricated, and measured. It consists of a U-slot rectangular microstrip patch antenna as the source, a Rogers RT6006 superstrate as the partially reflective surface, and the proposed shaped ground plane. Measured results on input reflection coefficients and radiation patterns agree well with simulated ones. Therefore, this new approach can be an effective way to enhance the gain bandwidth without increasing the cavity profile or using multi-layer superstrate structures.
Ju, M, Ding, C, Zhang, D & Guo, YJ 2018, 'Gamma-Correction-Based Visibility Restoration for Single Hazy Images', IEEE Signal Processing Letters, vol. 25, no. 7, pp. 1084-1088.
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© 1994-2012 IEEE. In this letter, a concise gamma-correction-based dehazing model (GDM) is proposed. This GDM explicitly describes the inner relationship between the gamma correction (GC) and the traditional scattering model. Combined with the existing priori constraints, GDM is further approximated into a one-dimensional (1-D) function to seek the only unknown constant that is used for haze removal. Using the determined constant, the scene albedo can be recovered, eliminating the haze from single hazy images. The proposed GDM is able to suppress the halo/blocking artifacts in the recovered results due to the scene albedo, which is less sensitive to the determined constant. Simulation results on different types of benchmark images verify that the proposed technique outperforms state-of-the-art methods in terms of both recovery, quality, and real-time performance.
Karmokar, DK, Guo, YJ, Qin, P-Y, Chen, S-L & Bird, TS 2018, 'Substrate Integrated Waveguide-Based Periodic Backward-to-Forward Scanning Leaky-Wave Antenna With Low Cross-Polarization', IEEE Transactions on Antennas and Propagation, vol. 66, no. 8, pp. 3846-3856.
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© 1963-2012 IEEE. For many leaky-wave antennas (LWAs), it is challenging to realize beam scanning through broadside. A problem is the presence of an open stopband (OSB), which restricts radiation in the broadside direction. In this paper, a novel substrate integrated waveguide (SIW)-based LWA is described to overcome the OSB problem and provide beam scanning continuously from the backward to the forward direction from a conventional periodic LWA. It is demonstrated that the n =-1 spatial harmonic can be excited efficiently from an SIW LWA and enables broadside radiation. However, it was found in our initial design that when the beam scans through the broadside, the cross-polarization level increases significantly compared to the beam close to the backfire direction. A technique is developed to reduce the cross-polarization level. As a result, a new antenna configuration is created. The antenna design has been realized and measured to validate the concept. The measured beam scanning range of the prototype is from -74° to +45° (119° of beam scanning) when the frequency sweeps from 7.625 to 11 GHz, and the measured cross-polarization level is 20.8 dB low at the main beam direction for the broadside beam.
Khan, AA, Abolhasan, M & Ni, W 2018, 'An Evolutionary Game Theoretic Approach for Stable and Optimized Clustering in VANETs', IEEE Transactions on Vehicular Technology, vol. 67, no. 5, pp. 4501-4513.
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© 1967-2012 IEEE. Discovering and maintaining efficient routes for data dissemination in vehicular ad hoc networks (VANETs) has proven to be a very challenging problem. Clustering is one of the control protocols used to provide efficient and stable routes for data dissemination. However, the rapid changes in network topology in VANETs creates frequent cluster reformation, which can seriously affect route stability. We propose a novel evolutionary game theoretic (EGT) framework to automate the clustering of nodes and nominations of cluster heads, to achieve cluster stability in VANETs. The equilibrium point is proven analytically and the stability is also tested using Lyapunov function. The performance of the proposed evolutionary game is empirically investigated with different cost functions using static and mobile scenarios. The simulation results demonstrate the effectiveness and robustness of our proposed EGT approach for different populations and speeds, thus reducing the overhead of frequent cluster reformation in VANETs.
Kong, F, Sun, X, Guo, YJ, Leung, VCM, Zhu, Q & Zhu, H 2018, 'Queue-Aware Power Consumption Minimization in Two-Tier Heterogeneous Networks', IEEE Transactions on Vehicular Technology, vol. 67, no. 9, pp. 8875-8889.
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© 1967-2012 IEEE. In this paper, we study the network average power consumption minimization problem in a two-tier heterogeneous network by optimally tuning the activation ratio of micro base stations (BSs) under the quality of service (QoS) constraints of the network mean queueing delay and the network signal-to-interference ratio (SIR) coverage. With the consideration of dynamic packets arrivals, each BS can either be busy or be idle depending on its queueing status. The network performance is thus critically determined by the traffic intensity of each BS. With the assumption of universal frequency reuse, the average traffic intensity of each tier is characterized by a set of fixed-point equations, which can be solved by a proposed iterative method. By using the approximation that BSs of the same tier have the same SIR coverage, the cumulative distribution function of the traffic intensity of each tier is further obtained. On that basis, the network average power consumption per area, the network mean queueing delay, and the network SIR coverage are characterized. Numerical results demonstrate that if the idle power coefficient is below a certain threshold, then the optimal activation ratio equals the one to minimize the network average power consumption per area; otherwise, the optimal activation ratio can be obtained according to the QoS constraints. It is further shown that universal frequency reuse outperforms spectrum partitioning in terms of both the network average power consumption and the network SIR coverage in the considered scenario.
Kusakunniran, W, Wu, Q, Ritthipravat, P & Zhang, J 2018, 'Hard exudates segmentation based on learned initial seeds and iterative graph cut', Computer Methods and Programs in Biomedicine, vol. 158, pp. 173-183.
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© 2018 Elsevier B.V. (Background and Objective): The occurrence of hard exudates is one of the early signs of diabetic retinopathy which is one of the leading causes of the blindness. Many patients with diabetic retinopathy lose their vision because of the late detection of the disease. Thus, this paper is to propose a novel method of hard exudates segmentation in retinal images in an automatic way. (Methods): The existing methods are based on either supervised or unsupervised learning techniques. In addition, the learned segmentation models may often cause miss-detection and/or fault-detection of hard exudates, due to the lack of rich characteristics, the intra-variations, and the similarity with other components in the retinal image. Thus, in this paper, the supervised learning based on the multilayer perceptron (MLP) is only used to identify initial seeds with high confidences to be hard exudates. Then, the segmentation is finalized by unsupervised learning based on the iterative graph cut (GC) using clusters of initial seeds. Also, in order to reduce color intra-variations of hard exudates in different retinal images, the color transfer (CT) is applied to normalize their color information, in the pre-processing step. (Results): The experiments and comparisons with the other existing methods are based on the two well-known datasets, e_ophtha EX and DIARETDB1. It can be seen that the proposed method outperforms the other existing methods in the literature, with the sensitivity in the pixel-level of 0.891 for the DIARETDB1 dataset and 0.564 for the e_ophtha EX dataset. The cross datasets validation where the training process is performed on one dataset and the testing process is performed on another dataset is also evaluated in this paper, in order to illustrate the robustness of the proposed method. (Conclusions): This newly proposed method integrates the supervised learning and unsupervised learning based techniques. It achieves the improved performa...
Lai, W, Ni, W, Wang, H & Liu, RP 2018, 'Analysis of Average Packet Loss Rate in Multi-Hop Broadcast for VANETs', IEEE Communications Letters, vol. 22, no. 1, pp. 157-160.
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© 2017 IEEE. Multi-hop relay can effectively improve the average packet loss rate (PLR) of vehicular ad hoc networks within a particular zone of interest. Challenges arise from analyzing the average PLR affected by distributed relay selections, which depend on the mobility of vehicles, the wireless channel conditions, and media access control (MAC). In this letter, we propose an average PLR analysis model taking into account the above three factors. However, the closed-form expression for the average PLR is intractable mainly due to the multiple integral of the joint distance distribution integrating with the channel conditions and vehicle mobility. An explicit expression for the upper bound of the average PLR is obtained by using Taylor series expansion, Holder's inequality, and the relay probability relaxation, which can facilitate the selection of the parameters at the physical and MAC layers for a better PLR. Simulation results validate our analyses.
Li, K, Ni, W, Duan, L, Abolhasan, M & Niu, J 2018, 'Wireless Power Transfer and Data Collection in Wireless Sensor Networks', IEEE Transactions on Vehicular Technology, vol. 67, no. 3, pp. 2686-2697.
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© 1967-2012 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, whereas the other nodes 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 EHMDP, aiming to minimize data packet loss from a network of sensor nodes in terms of the nodes' energy consumption and data queue state information. The scheduling problem is first formulated by a centralized MDP model, assuming that the complete states of each node are well known by the base station. This presents the upper bound of the data that can be collected in a rechargeable wireless sensor network. Next, we relax the assumption of the availability of full state information so that the data transmission and WPT can be semidecentralized. The simulation results show that, in terms of network throughput and packet loss rate, the proposed algorithm significantly improves the network performance.
Li, L, Liu, Z & Zhang, J 2018, 'Unsupervised image co-segmentation via guidance of simple images', Neurocomputing, vol. 275, pp. 1650-1661.
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© 2017 Elsevier B.V. This paper proposes a novel image co-segmentation method, which aims to segment the common objects in a group of images. The proposed method takes advantages of the reliability of simple images and successfully improves the performance. The images are first ranked by the complexities based on their saliency maps. Then, the simple images, in which objects are common and easy to be segmented, are selected and processed to obtain their segmentation results, these segmentation results are taken as the samples of the targeted objects. Finally, the remaining complicated images are segmented with the guidance of the samples. The experiments on the iCoseg dataset demonstrate the outperformance and robustness of the proposed method.
Li, M, Liu, Y & Guo, YJ 2018, 'Shaped Power Pattern Synthesis of a Linear Dipole Array by Element Rotation and Phase Optimization Using Dynamic Differential Evolution', IEEE Antennas and Wireless Propagation Letters, vol. 17, no. 4, pp. 697-701.
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Li, M, Yang, Y, Xu, KD, Zhu, X & Wong, SW 2018, 'Microwave On-Chip Bandpass Filter Based on Hybrid Coupling Technique', IEEE Transactions on Electron Devices, vol. 65, no. 12, pp. 5453-5459.
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© 2018 IEEE. In this paper, a novel on-chip circuit design approach is proposed using hybrid coupling technique. Taking advantage of this technique, a microwave bandpass filter (BPF) is proposed as a design example for proof of concept. Based on stub-loaded stepped-impedance transmission lines and folded stepped-impedance meander line from different metal layers, the proposed BPF can generate three transmission zeros (TZs) and two transmission poles (TPs), which are excited through the hybrid mutual couplings between the inductive and capacitive metals. To understand the principle of this configuration, an equivalent LC-circuit model is presented and simplified, of which the TZs and TPs of the proposed BPF are estimated by the extracted transfer function. The calculated results exhibit good agreements with the simulated and measured ones. In addition, the bandwidth and center frequency of the proposed BPF can be tuned flexibly. Finally, to further demonstrate the feasibility of this approach in practice, the structure is implemented and fabricated in a commercial 0.13- μm SiGe (Bi)-CMOS technology. The measurement results show that the proposed BPF, whose chip size is 0.39 mm × 0.45 mm (excluding the test pads), can realize a wide bandwidth from 19.7 to 33.2 GHz with a return loss of 15.8 dB and insertion loss of 3.8 dB at the center frequency of 26.5 GHz.
Lin, J-Y, Wong, S-W, Zhu, L, Yang, Y, Zhu, X, Xie, Z-M & He, Y 2018, 'A Dual-Functional Triple-Mode Cavity Resonator With the Integration of Filters and Antennas', IEEE Transactions on Antennas and Propagation, vol. 66, no. 5, pp. 2589-2593.
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Lin, W, Chen, S-L, Ziolkowski, RW & Guo, YJ 2018, 'Reconfigurable, Wideband, Low-Profile, Circularly Polarized Antenna and Array Enabled by an Artificial Magnetic Conductor Ground', IEEE Transactions on Antennas and Propagation, vol. 66, no. 3, pp. 1564-1569.
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© 1963-2012 IEEE. A reconfigurable, wideband, and low-profile circular polarization (CP) antenna is presented. Its wideband CP reconfigurability is realized by incorporating RF switches into a cross-bowtie radiator. A compact, wide bandwidth, and polarization-independent artificial magnetic conductor ground plane is developed to minimize the overall profile of the antenna while maintaining its wide bandwidth. The simplicity of this single-element design facilitates the realization of a reconfigurable, wide bandwidth CP array that achieves higher directivity without changing its overall profile. Prototypes of the single element and of a 1 × 4 array of these elements were fabricated and tested. The measured results for both prototypes are in good agreement with their simulated values, validating their design principles. They are low profile with a height ∼ 0.05 λ0. The array exhibits a wide fractional operational bandwidth: 1.65 GHz (21.7%), and a high realized gain: 13 dBic. Since they would enhance their channel capacity and avoid polarization mismatch issues, these reconfigurable CP antenna systems are very suitable for modern wireless systems.
Liu, Y, Bai, J, Xu, KD, Xu, Z, Han, F, Liu, QH & Jay Guo, Y 2018, 'Linearly Polarized Shaped Power Pattern Synthesis With Sidelobe and Cross-Polarization Control by Using Semidefinite Relaxation', IEEE Transactions on Antennas and Propagation, vol. 66, no. 6, pp. 3207-3212.
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© 1963-2012 IEEE. In this communication, the problem of synthesizing a linearly polarized shaped power pattern with accurate control on both sidelobe and cross-polarization (XP) levels is considered. For a user-defined desired polarization direction, the definitions of realizable co-polarization (COP) and XP directions for an arbitrary propagation direction in the shaped pattern are presented. With the help of such definitions, the considered problem is formulated as finding appropriate excitations so as to produce a shaped power pattern in which the realizable COP component meets prescribed lower and upper bounds, the realizable XP component and the total power pattern are less than their upper bounds in the regions of interest. The semidefinite relaxation method in the literature is then extended to solve this vectorial pattern synthesis problem. The proposed method can include the mutual coupling and platform effects by using vectorial active element patterns of an antenna array. A set of synthesis examples with different array geometries and radiation requirements are conducted to validate the effectiveness and advantages of the proposed method.
Liu, Y, Cheng, J, Xu, KD, Yang, S, Liu, QH & Guo, YJ 2018, 'Reducing the Number of Elements in the Synthesis of a Broadband Linear Array With Multiple Simultaneous Frequency-Invariant Beam Patterns', IEEE Transactions on Antennas and Propagation, vol. 66, no. 11, pp. 5838-5848.
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© 2018 IEEE. The problem of reducing the number of elements in a broadband linear array with multiple simultaneous crossover frequency-invariant (FI) patterns is considered. Different from the single FI pattern array case, every element channel in the multiple FI pattern array is divided and followed by multiple finite-impulse-response (FIR) filters, and each of the multiple FIR filters has a set of coefficients. In this situation, a collective filter coefficient vector and its energy bound are introduced for each element, and then the problem of reducing the number of elements is transformed as minimizing the number of active collective filter coefficient vectors. In addition, the radiation characteristics including beam pointing direction, mainlobe FI property, sidelobe level, and space-frequency notching requirement for each of the multiple patterns can be formulated as multiple convex constraints. The whole synthesis method is implemented by performing an iterative second-order cone programming (SOCP). This method can be considered as a significant extension of the original SOCP for synthesizing broadband sparse array with single FI pattern. Numerical synthesis results show that the proposed method by synthesizing multiple discretized crossover FI patterns can save more elements than the original iterative SOCP by using a single continuously scannable FI pattern for covering the same space range. Moreover, even for multiple FI-patterns case with complicated space-frequency notching, the proposed method is still effective in the reduction of the number of elements.
Luo, Y, Pan, J, Zhang, JA & Huang, S 2018, 'Worst-Case Performance Optimization Beamformer with Embedded Array’s Active Pattern', International Journal of Antennas and Propagation, vol. 2018, pp. 1-5.
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This paper proposes an adaptive array beamforming method by embedding antennas’ active pattern in the worst-case performance optimization algorithm. This method can significantly reduce the beamformer’s performance degradation caused by inconsistency between hypothesized ideal array models and practical ones. Simulation and measured results consistently demonstrate the robustness and effectiveness of the proposed method in dealing with array manifold mismatches.
Lyu, X, Ni, W, Tian, H, Liu, RP, Wang, X, Giannakis, GB & Paulraj, A 2018, 'Distributed Online Optimization of Fog Computing for Selfish Devices With Out-of-Date Information', IEEE Transactions on Wireless Communications, vol. 17, no. 11, pp. 7704-7717.
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© 2002-2012 IEEE. By performing fog computing, a device can offload delay-tolerant computationally demanding tasks to its peers for processing, and the results can be returned and aggregated. In distributed wireless networks, the challenges of fog computing include lack of central coordination, selfish behaviors of devices, and multi-hop signaling delays, which can result in outdated network knowledge and prevent effective cooperations beyond one hop. This paper presents a new approach to enable cooperations of N selfish devices over multiple hops, where selfish behaviors are discouraged by a tit-for-tat mechanism. The tit-for-tat incentive of a device is designed to be the gap between the helps (in terms of energy) the device has received and offered; and indicates how much help the device can offer at the next time slot. The tit-for-tat incentives can be evaluated at every device by having all devices broadcast how much help they offered in the past time slot, and used by all devices to schedule task offloading and processing. The approach achieves asymptotic optimality in a fully distributed fashion with a time-complexity of less than O(N2). The optimality loss resulting from multi-hop signaling delays and consequently outdated tit-for-tat incentives is proved to asymptotically diminish. Simulation results show that our approach substantially reduces the time-average energy consumption of the state of the art by 50% and accommodates more tasks, by engaging devices hops away under multi-hop delays.
Lyu, X, Ren, C, Ni, W, Tian, H & Liu, RP 2018, 'Distributed Optimization of Collaborative Regions in Large-Scale Inhomogeneous Fog Computing', IEEE Journal on Selected Areas in Communications, vol. 36, no. 3, pp. 574-586.
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© 1983-2012 IEEE. Fog computing enables resource-limited network devices to help each other with computationally demanding tasks, but has yet to be implemented in large scales due to sophisticated control and network inhomogeneity. This paper presents a new fully distributed online optimization to asymptotically minimize the time-average cost of fog computing, where tasks are selected to be offloaded and processed independently between different links and devices by measuring their cost effectiveness at each time slot. A key contribution is that we optimize the cost-effectiveness measures which achieve the asymptotic optimality over infinite time. Another contribution is that we optimize placeholders at the devices; which create collaborative computing regions of tasks in the vicinity of the point of capture, prevent tasks being offloaded beyond, preserve the asymptotic optimality and reduce delay. This is achieved in a distributed fashion by discovering the optimal substructure of the placeholders. Simulations show that the average size of collaborative regions is only 3.2 out of total 500 servers, and the system income increases by 43% as compared with existing techniques.
Lyu, X, Ren, C, Ni, W, Tian, H, Liu, RP & Guo, YJ 2018, 'Multi-Timescale Decentralized Online Orchestration of Software-Defined Networks', IEEE Journal on Selected Areas in Communications, vol. 36, no. 12, pp. 2716-2730.
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© 1983-2012 IEEE. Decentralized orchestration of the control plane is critical to the scalability and reliability of software-defined network (SDN). However, existing orchestrations of SDN are either one-off or centralized, and would be inefficient the presence of temporal and spatial variations in traffic requests. In this paper, a fully distributed orchestration is proposed to minimize the time-average cost of SDN, adapting to the variations. This is achieved by stochastically optimizing the on-demand activation of controllers, adaptive association of controllers and switches, and real-time request processing and dispatching. The proposed approach is able to operate at multiple timescales for activation and association of controllers, and request processing and dispatching, thereby alleviating potential service interruptions caused by orchestration. A new analytic framework is developed to confirm the asymptotic optimality of the proposed approach in the presence of non-negligible signaling delays between controllers. Corroborated from extensive simulations, the proposed approach can save up to 73% the time-average operational cost of SDN, as compared to the existing static orchestration.
Lyu, X, Tian, H, Ni, W, Zhang, Y, Zhang, P & Liu, RP 2018, 'Energy-Efficient Admission of Delay-Sensitive Tasks for Mobile Edge Computing', IEEE Transactions on Communications, vol. 66, no. 6, pp. 2603-2616.
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© 1972-2012 IEEE. Task admission is critical to delay-sensitive applications in mobile edge computing, but is technically challenging due to its combinatorial mixed nature and consequently limited scalability. We propose an asymptotically optimal task admission approach which is able to guarantee task delays and achieve (1 - ∈)-approximation of the computationally prohibitive maximum energy saving at a time-complexity linearly scaling with devices. ∈ is linear to the quantization interval of energy. The key idea is to transform the mixed integer programming of task admission to an integer programming (IP) problem with the optimal substructure by pre-admitting resource-restrained devices. Another important aspect is a new quantized dynamic programming algorithm which we develop to exploit the optimal substructure and solve the IP. The quantization interval of energy is optimized to achieve an [O(∈),O(1/∈)]-tradeoff between the optimality loss and time complexity of the algorithm. Simulations show that our approach is able to dramatically enhance the scalability of task admission at a marginal cost of extra energy, as compared with the optimal branch and bound method, and can be efficiently implemented for online programming.
Ma, X, Liang, J, Liu, R, Ni, W, Li, Y, Li, R, Ma, W & Qi, C 2018, 'A Survey on Data Storage and Information Discovery in the WSANs-Based Edge Computing Systems', Sensors, vol. 18, no. 2, pp. 546-546.
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In the post-Cloud era, the proliferation of Internet of Things (IoT) has pushed the horizon of Edge computing, which is a new computing paradigm with data are processed at the edge of the network. As the important systems of Edge computing, wireless sensor and actuator networks (WSANs) play an important role in collecting and processing the sensing data from the surrounding environment as well as taking actions on the events happening in the environment. In WSANs, in-network data storage and information discovery schemes with high energy efficiency, high load balance and low latency are needed because of the limited resources of the sensor nodes and the real-time requirement of some specific applications, such as putting out a big fire in a forest. In this article, the existing schemes of WSANs on data storage and information discovery are surveyed with detailed analysis on their advancements and shortcomings, and possible solutions are proposed on how to achieve high efficiency, good load balance, and perfect real-time performances at the same time, hoping that it can provide a good reference for the future research of the WSANs-based Edge computing systems.
Mangca, DC, Gerasta, OJ, Luna, AL, Zhu, X & Hora, JA 2018, 'On-the-fly Computation Method in Field-Programmable Gate Array for Analog-to-Digital Converter Linearity Testing', Journal of Engineering and Technological Sciences, vol. 50, no. 5, pp. 589-606.
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This paper presents a new approach to linearity testing of analog-to-digital converters (ADCs) through on-the-fly computation in field-programmable gate array (FPGA) hardware. The proposed method computes the linearity while it is processing without compromising the accuracy of the measurement, so very little overhead time is required to compute the final linearity. The results will be displayed immediately after a single ramp is supplied to the device under test. This is a cost-effective chip testing solution for semiconductor companies, achieved by reducing computing time and utilization of low-cost and low-specification automatic test equipment (ATE). The experimental results showed that the on-the-fly computation method significantly reduced the computation time (up to 44.4%) compared to the conventional process. Thus, for every 100M 12-bit ADC tested with 32 hits per code, the company can save up to 139,972 Php on electricity consumption.
Mishra, SK, Puthal, D, Rodrigues, JJPC, Sahoo, B & Dutkiewicz, E 2018, 'Sustainable Service Allocation Using a Metaheuristic Technique in a Fog Server for Industrial Applications', IEEE Transactions on Industrial Informatics, vol. 14, no. 10, pp. 4497-4506.
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© 2005-2012 IEEE. Reducing energy consumption in the fog computing environment is both a research and an operational challenge for the current research community and industry. There are several industries such as finance industry or healthcare industry that require a rich resource platform to process big data along with edge computing in fog architecture. As a result, sustainable computing in a fog server plays a key role in fog computing hierarchy. The energy consumption in fog servers depends on the allocation techniques of services (user requests) to a set of virtual machines (VMs). This service request allocation in a fog computing environment is a nondeterministic polynomial-time hard problem. In this paper, the scheduling of service requests to VMs is presented as a bi-objective minimization problem, where a tradeoff is maintained between the energy consumption and makespan. Specifically, this paper proposes a metaheuristic-based service allocation framework using three metaheuristic techniques, such as particle swarm optimization (PSO), binary PSO, and bat algorithm. These proposed techniques allow us to deal with the heterogeneity of resources in the fog computing environment. This paper has validated the performance of these metaheuristic-based service allocation algorithms by conducting a set of rigorous evaluations.
Movassaghi, S, Smith, DB, Abolhasan, M & Jamalipour, A 2018, 'Opportunistic Spectrum Allocation for Interference Mitigation Amongst Coexisting Wireless Body Area Networks', ACM Transactions on Sensor Networks, vol. 14, no. 2, pp. 1-22.
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Wireless Body Area Networks (WBANs) are seen as the enabling technology for developing new generations of medical applications, such as remote health monitoring. As such it is expected that WBANs will predominantly transport mission-critical and delay sensitive data. A key strategy towards building a reliable WBAN is to ensure such networks are highly immune to interference. To achieve this, new and intelligent wireless spectrum allocation strategies are required not only to avoid interference, but also to make best-use of the limited available spectrum. This article presents a new spectrum allocation scheme referred to as Smart Channel Assignment (SCA), which maximizes the resource usage and transmission speed by deploying a partially-orthogonal channel assignment scheme between coexisting WBANs as well as offering a convenient tradeoff among spectral reuse efficiency, transmission rate, and outage. Detailed analytical studies verify that the proposed SCA strategy is robust to variations in channel conditions, increase in sensor node-density within each WBAN, and an increase in number of coexisting WBANs.
Nan, Y, Huang, X & Guo, YJ 2018, 'Generalized Continuous Wave Synthetic Aperture Radar for High Resolution and Wide Swath Remote Sensing', IEEE Transactions on Geoscience and Remote Sensing, vol. 56, no. 12, pp. 7217-7229.
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© 2018 IEEE. A generalized continuous wave synthetic aperture radar (GCW-SAR) concept is proposed in this paper. By using full-duplex radio frontend and continuous wave signaling, the GCW-SAR system can overcome a number of limitations inherent within the existing SAR systems and achieve high-resolution and wide-swath remote sensing with low-power signal transmission. Unlike the conventional pulsed SAR and the frequency-modulated continuous-wave SAR, the GCW-SAR reconstructs a radar image by directly correlating the received 1-D raw data after self-interference cancellation with predetermined location-dependent reference signals. A fast imaging algorithm, called the piecewise constant Doppler (PCD) algorithm, is also proposed, which produces the radar image recursively in the azimuth direction without any intermediate step, such as range compression and migration compensation, as required by conventional algorithms. By removing the stop-and-go assumption or slow-time sampling in azimuth, the PCD algorithm not only achieves better imaging quality but also allows for more flexible waveform and system designs. Analyses and simulations show that the GCW-SAR tolerates significant self-interference and works well with a large selection of various system parameters. The work presented in this paper establishes a solid theoretical foundation for next-generation imaging radars.
Nguyen, DN, Dutkiewicz, E & Krunz, M 2018, 'Harvesting Short-Lived White Spaces via Opportunistic Traffic Offloading Between Mobile Service Providers', IEEE Transactions on Cognitive Communications and Networking, vol. 4, no. 3, pp. 635-647.
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Currently, Wi-Fi (IEEE 802.11) is the most widely adopted wireless technology for mobile traffic offloading at hot spots. Despite its great success, Wi-Fi is constrained by the over-crowded unlicensed spectrum, which leads to poor user experience, especially in urban areas. This paper introduces an opportunistic cooperation framework that allows mobile service providers (MSPs) to offload traffic onto each other's network by harvesting short-lived spectrum/resources of cellular systems. Specifically, through traffic offloading, MSPs aim to maximize their profit while maintaining their quality of service (QoS) commitments. For that purpose, we model the strategic cooperation between MSPs as a stochastic Markov game in which the dynamics of resource availability and user behaviors are captured via a Markov decision process. We prove that the game is irreducible and admits a Nash Equilibrium at which all MSPs benefit from traffic offloading. A practical algorithm that uses only local information to govern traffic offloading at MSPs is then developed. Numerical simulations show that by designing appropriate profit sharing contracts, our proposed algorithm can achieve almost the same performance as that of a socially optimal solution. The derived traffic offloading strategies not only improve QoS and revenue for MSPs, but also can be used to guide MSPs on when to turn off their base stations while the traffic volume is light (e.g., during nighttime).
Nguyen, DN, Krunz, M & Dutkiewicz, E 2018, 'Full-Duplex MIMO Radios: A Greener Networking Solution', IEEE Transactions on Green Communications and Networking, vol. 2, no. 3, pp. 652-665.
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© 2017 IEEE. Relative to half-duplex (HD) radios, in-band full-duplex (FD) radios have the potential to double a link's capacity. However, such gain may not necessarily extend to the network-wide throughput, which may actually degrade under FD radios due to excessive network interference. This paper identifies the unique advantages of FD radios and leverages multi-input multioutput (MIMO) communications to translate the FD spectral efficiency gain at the PHY level to the throughput and power efficiency gain at the network layer. We first derive sufficient conditions under which FD-MIMO radios can asymptotically double the throughput of the same network of HD-MIMO ones. Specifically, if a network of 2N HD radios (N links) can achieve a total throughput of dN bps (i.e., d bps per link), then an FD-capable network with the same number of links and network/channel realization can achieve 2N (d-1) bps [i.e., (d-1) bps per direction of a bidirectional link]. To leverage this theoretical gain, we exploit the 'spatial signature' readily captured in the network interference to design an MAC protocol that allows multiple FD links to concurrently communicate while adapting their radiation patterns to minimize network interference. The protocol does not require any feedback nor coordination among nodes. Extensive simulations show that the proposed MAC design dramatically outperforms traditional CSMA-based and the non-orthogonal multiple access protocols with either HD or FD radios with respect to both throughput and energy efficiency. Note that in the literature, network interference is often treated as colored noise that then gets whiten during the signal detection process. However, through our MAC protocol, we emphasize that, unlike random noise, network interference has its own structure that can be 'mined' for 'intelligence' to better align the transceiver's signal.
Ni, W, Zhang, JA, Fang, Z, Abolhasan, M, Liu, RP & Guo, YJ 2018, 'Analysis of Finite Buffer in Two-Way Relay: A Queueing Theoretic Point of View', IEEE Transactions on Vehicular Technology, vol. 67, no. 4, pp. 3690-3694.
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© 1967-2012 IEEE. The impact of a finite relay buffer on the throughput of two-way relay is analyzed from a new queueing theoretic point of view. Distinctively from recent Markov model based analyses, the proposed queueing theoretic analysis is able to infer closed-form asymptotic upper bounds for the throughput, shed valuable insights, and point out limitations in the recent analyses. Validated by simulations, our queueing theoretic analysis reveals that the throughput is increasingly insusceptible to the size of the relay buffer, as the buffer enlarges. Moreover, locking the relay in transmitting xored packets can hardly improve the throughput, especially under balanced channel conditions. This is due to the fact that the relay queues stabilize nonempty, and hence, xored packets are forwarded in most cases.
Niazi, M, Mishra, A & Gill, AQ 2018, 'What Do Software Practitioners Really Think About Software Process Improvement Project Success? An Exploratory Study', Arabian Journal for Science and Engineering, vol. 43, no. 12, pp. 7719-7735.
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© 2018, King Fahd University of Petroleum & Minerals. Software practitioners have always shown a significant interest in implementing software process improvement (SPI) initiatives to ensure the delivery of quality products. Software industry and SPI methodologies have evolved over a period of time; however, still many SPI initiatives have not been successful. There is a need to understand software practitioners’ perspectives on SPI success which can be helpful for tailoring or improving effective situation-specific SPI methodologies. This research presents an exploratory study of Turkish software development organizations. The main research question is: What software practitioners’ really think about SPI project success. This study was conducted with 27 Turkish software development organizations to identity and analyse important SPI factors that contribute to the success of SPI projects. The results reveal that professional growth, increased professional recognition, project planning, monitoring of project risks, providing technical support, adoption of current technologies, strong leadership and commitment are among the highest ranked factors that contribute towards the success of SPI initiatives. The findings of this research provide a foundation for further work in tailoring and improving situation-specific SPI methodologies for software project environments.
Pham, TM, Farrell, R, Dooley, J, Dutkiewicz, E, Nguyen, DN & Tran, L-N 2018, 'Efficient Zero-Forcing Precoder Design for Weighted Sum-Rate Maximization With Per-Antenna Power Constraint', IEEE Transactions on Vehicular Technology, vol. 67, no. 4, pp. 3640-3645.
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© 1967-2012 IEEE. This paper proposes an efficient (semi-closed-form) zero-forcing (ZF) precoder design for the weighted sum-rate maximization problem under per-antenna power constraint (PAPC). Existing approaches for this problem are based on either interior-point methods that do not favorably scale with the problem size or subgradient methods that are widely known to converge slowly. To address these shortcomings, our proposed method is derived from three elements: minimax duality, alternating optimization (AO), and successive convex approximation (SCA). Specifically, the minimax duality is invoked to transform the considered problem into an equivalent minimax problem, for which we then recruit AO and SCA to find a saddle point, which enables us to take advantages of closed-form expressions and hence achieve fast convergence rate. Moreover, the complexity of the proposed method scales linearly with the number of users, compared to cubically for the standard interior-point methods. We provide an analytical proof for the convergence of the proposed method and numerical results to demonstrate its superior performance over existing approaches. Our proposed method offers a powerful tool to characterize the achievable rate region of ZF schemes under PAPC for massive multiple-input multiple-output.
Pham, TT, Nguyen, DN, Dutkiewicz, E, Center, JR, Eisman, JA & Nguyen, TV 2018, 'A profiling analysis of contributions of cigarette smoking, dietary calcium intakes, and physical activity to fragility fracture in the elderly', Scientific Reports, vol. 8, no. 1.
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AbstractFragility fracture and bone mineral density (BMD) are influenced by common and modifiable lifestyle factors. In this study, we sought to define the contribution of lifestyle factors to fracture risk by using a profiling approach. The study involved 1683 women and 1010 men (50+ years old, followed up for up to 20 years). The incidence of new fractures was ascertained by X-ray reports. A “lifestyle risk score” (LRS) was derived as the weighted sum of effects of dietary calcium intake, physical activity index, and cigarette smoking. Each individual had a unique LRS, with higher scores being associated with a healthier lifestyle. Baseline values of lifestyle factors were assessed. In either men or women, individuals with a fracture had a significantly lower age-adjusted LRS than those without a fracture. In men, each unit lower in LRS was associated with a 66% increase in the risk of total fracture (non-adjusted hazard ratio [HR] 1.66; 95% CI, 1.26 to 2.20) and still significant after adjusting for age, weight or BMD. However, in women, the association was uncertain (HR 1.30; 95% CI, 1.11 to 1.53). These data suggest that unhealthy lifestyle habits are associated with an increased risk of fracture in men, but not in women, and that the association is mediated by BMD.
Pupatwibul, P, Banjar, A, Hossain, I, Braun, R & Moulton, B 2018, 'A novel software-defined networking controller: The Distributed Active Information Model (DAIM)', International Journal of Electronics and Telecommunications, vol. 64, no. 2, pp. 209-216.
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This paper presents a new OpenFlow controller: the Distributed Active Information Model (DAIM). The DAIM controller was developed to explore the viability of a logically distributed control plane. It is implemented in a distributed way throughout a software-defined network, at the level of the switches. The method enables local process flows, by way of local packet switching, to be controlled by the distributed DAIM controller (as opposed to a centralised OpenFlow controller). The DAIM ecosystem is discussed with some sample code, together with flowcharts of the implemented algorithms. We present implementation details, a testing methodology, and an experimental evaluation. A performance analysis was conducted using the Cbench open benchmarking tool. Comparisons were drawn with respect to throughput and latency. It is concluded that the DAIM controller can handle a high throughput, while keeping the latency relatively low. We believe the results to date are potentially very interesting, especially in light of the fact that a key feature of the DAIM controller is that it is designed to enable the future development of autonomous local flow process and management strategies.
Qin, C, Ni, W, Tian, H, Liu, RP & Guo, YJ 2018, 'Joint Beamforming and User Selection in Multiuser Collaborative MIMO SWIPT Systems With Nonnegligible Circuit Energy Consumption', IEEE Transactions on Vehicular Technology, vol. 67, no. 5, pp. 3909-3923.
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© 1967-2012 IEEE. Multiantenna beamforming has potential to improve the efficiency of simultaneous wireless information and power transfer (SWIPT). Existing designs are focused on the downlink of multiple-input-single-output under the assumption of single-antenna users and negligible energy consumption in users' circuitry, despite the fact that using multiple antennas on the user side can further improve system efficiency. In this paper, novel multiuser collaborative multiple-input multiple-output SWIPT systems are studied under the assumption of nonnegligible circuit energy consumption. Particularly, we convexify and maximize the uplink sum rate of active users, while maintaining the quality of service of their downlink data. The beamformers and durations of both links, and the power splitting factors of individual users are jointly optimized, using semidefinite programming and golden search. Further, the selection of active users is optimized, where all users are assumed to be active in the beginning and those detrimental to the sum-rate maximization are continually deactivated. Evident from simulations, the proposed approaches can eliminate the need for computationally prohibitive combinatorial integer programming at a marginal cost of the sum rate.
Qin, P, Chen, S & Guo, YJ 2018, 'Recent Advances in Reconfigurable Antennas at University of Technology Sydney', Journal of Communications and Information Networks, vol. 3, no. 1, pp. 15-20.
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Qin, P-Y, Ji, L-Y, Chen, S-L & Guo, YJ 2018, 'Dual-Polarized Wideband Fabry–Perot Antenna With Quad-Layer Partially Reflective Surface', IEEE Antennas and Wireless Propagation Letters, vol. 17, no. 4, pp. 551-554.
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© 2002-2011 IEEE. A new quad-layer partially reflective surface (PRS) is presented in this letter for dual-polarized Fabry-Perot (FP) cavity antennas with an improved gain bandwidth. Four layers of metallic square rings are printed on each side of two dielectric substrates separated by an air gap of about λ/27 (λ is the wavelength in the open air) at 5.5 GHz. The total profile of the FP cavity is about λ /2. By properly choosing the dimensions of square rings and the distance between the two substrates, the phase of the reflection coefficient of the PRS increases with the operating frequency, demonstrating a broadband property. In order to validate the performance of the proposed PRS, a dual-polarized FP antenna is designed, which has peak realized gains of 14.7 and 15.5 dBi with 1 dB bandwidths of more than 10% for two polarizations. Furthermore, the input reflection coefficients are lower than -15 dB in the 5.05-5.8 GHz band, and the isolation of the dual-polarized modes is more than 30 dB.
Qumer Gill, A, Loumish, A, Riyat, I & Han, S 2018, 'DevOps for information management systems', VINE Journal of Information and Knowledge Management Systems, vol. 48, no. 1, pp. 122-139.
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PurposeDevelopment and operations (DevOps) is complex in nature. Organizations are unsure how to effectively establish a DevOps capability for the continuous delivery of information management systems. This paper aims to compile and analyze DevOps by applying the well-known systematic literature review (SLR) approach. This review is intended to provide a knowledge base to support the informed, effective and less risky adoption of DevOps for information management systems.Design/methodology/approachIn this qualitative research study, the SLR method was applied to identify 3,790 papers, of which, 32 relevant papers were selected and reviewed.FindingsThe results are organized using the well-known ISO/IEC 24744 metamodel elements: people (roles), process, technology and artifacts. In total 11 major roles, 6 processes, 23 technologies, 5 artifacts and 7 challenges (including 6 corresponding solutions) were found. DevOps engineer is becoming a newly identified role. Continuous delivery pipeline and continuous improvement are the most highlighted major DevOps processes. Build system technology is becoming the key focus of DevOps. Finally, major challenges are around people and culture and the misunderstanding of DevOps. Potential research areas are: DevOps analytics, artifacts and tool–chain integration.Research limitations/implicationsThe research findings will serve as a resource for both practitioners and researchers who have interest in the research and adoption of DevOps for information management systems.Multimedia Tools and Applications, vol. 77, no. 13, pp. 17247-17267.
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© 2017, Springer Science+Business Media, LLC. Affective image analysis, which estimates humans’ emotion reflection on images, has attracted increasing attention. Most of the existing methods focus on developing efficient visual features according to theoretical and empirical concepts, and extract these features from an image as a whole. However, analyzing emotion from an entire image, can only extract the dominant emotion conveyed by the whole image, which ignores the affective differences existing among different regions within the image. This may reduce the performance of emotion recognition, and limit the range of possible applications. In this paper, we are the first to propose the concept of affective map, by which image emotion can be represented at region-level. In an affective map, the value of each pixel represents the probability of the pixel belonging to a certain emotion category. Two popular application exemplars, i.e. affective image classification and visual saliency computing, are explored to prove the effectiveness of the proposed affective map. Analyzing detailed image emotion at a region-level, the accuracy of affective image classification has been improved 5.1% on average. The Area Under the Curve (AUC) of visual saliency detection has been improved 15% on average.
Rouzbehi, K, Heidary Yazdi, SS & Shariati Moghadam, N 2018, 'Power Flow Control in Multi-Terminal HVDC Grids Using a Serial-Parallel DC Power Flow Controller', IEEE Access, vol. 6, pp. 56934-56944.
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Saputra, YM, Hoang, DT, Nguyen, DN & Dutkiewicz, E 2018, 'A Novel Mobile Edge Network Architecture with Joint Caching-Delivering and Horizontal Cooperation', IEEE Transactions on Mobile Computing, vol. 20, no. 1, pp. 19-31.
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Mobile edge caching/computing has been emerging as a promising paradigm toprovide new services (e.g., ultra-high rate, ultra-reliable, and/or low-latencycommunications) in future wireless networks. In this paper, we introduce anovel mobile edge caching network architecture that leverages the optimal jointcaching-delivering with horizontal cooperation among mobile edge nodes (MENs),namely JOCAD. Under this architecture, MENs cooperate with each other in bothcaching and delivering contents, aiming to simultaneously minimize the totalaverage delay for the mobile users and mitigate the network traffic on thebackhaul link. Extensive simulations demonstrate that the proposed solutionscan reduce the total average delay for the whole network up to 40% comparedwith the most frequency-of-access policy, and up to 25% compared with locallyoptimal caching policy (i.e., without collaboration). Furthermore, the proposedsolutions also increase the cache hit rate for the network by four times,thereby dramatically reducing the traffic load on the backhaul network.
Saputra, YM, Hoang, DT, Nguyen, DN, Dutkiewicz, E, Niyato, D & Kim, DI 2018, 'Distributed Deep Learning at the Edge: A Novel Proactive and Cooperative Caching Framework for Mobile Edge Networks', IEEE Wireless Communications Letters, vol. 8, no. 4, pp. 1-1.
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This letter proposes two novel proactive cooperative caching approaches usingdeep learning (DL) to predict users' content demand in a mobile edge cachingnetwork. In the first approach, a (central) content server takesresponsibilities to collect information from all mobile edge nodes (MENs) inthe network and then performs our proposed deep learning (DL) algorithm topredict the content demand for the whole network. However, such a centralizedapproach may disclose the private information because MENs have to share theirlocal users' data with the content server. Thus, in the second approach, wepropose a novel distributed deep learning (DDL) based framework. The DDL allowsMENs in the network to collaborate and exchange information to reduce the errorof content demand prediction without revealing the private information ofmobile users. Through simulation results, we show that our proposed approachescan enhance the accuracy by reducing the root mean squared error (RMSE) up to33.7% and reduce the service delay by 36.1% compared with other machinelearning algorithms.
Shariati, N, Scott, JR, Schreurs, D & Ghorbani, K 2018, 'Multitone Excitation Analysis in RF Energy Harvesters—Considerations and Limitations', IEEE Internet of Things Journal, vol. 5, no. 4, pp. 2804-2816.
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© 2018 IEEE. The effect of multitone excitation on the dc response of a voltage-doubler radio frequency energy harvester is analyzed. Theoretical analysis as well as frequency and time domain (TD) simulations were conducted to clarify the findings. Measurements were also carried out to validate the results. The measured, simulations and theoretical results are in good agreement. This paper focuses on evaluating the performance of a voltage doubler rectifier under multitone excitation (input power is the same in the single-tone and multitone case). Based on TD and harmonic balance simulations, theoretical and measurement analyses, it is evident that the application of multiple tones simultaneously within the matched frequency band and with the same average available power results in a lower average output dc power when compared with the single-tone case with the same input power. This trend is evident over a broad low input power range of −50 to −10 dBm (0.01–100 µW).
Soldani, D, Guo, YJ, Barani, B, Mogensen, P, I, C-L & Das, SK 2018, '5G for Ultra-Reliable Low-Latency Communications', IEEE Network, vol. 32, no. 2, pp. 6-7.
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© 2018 IEEE. The articles in this special section focus on fifth generation (5G) mobile communication for ultra-reliable low-latency communications. With the expected superior performance to the current generation of mobile networks, 5G systems are poised to support new and diverse usage scenarios and applications, thus enriching the lives of citizens and the productivity of industry and public sectors. The widely accepted scenarios for 5G include enhanced mobile broadband (eMBB), addressing human-centric use cases for access to multimedia content, services and data; ultra-reliable low-latency communications (URLLC) with strict requirements, especially in terms of latency and reliability; and massive machine type communications (mMTC) for a very large number of connected devices typically transmitting a relatively low volume of non-delay-sensitive data. The articles in this section present the most relevant scenarios, prominent research outcomes, and state-of-the-art advances of 5G systems for URLLC achieving the Third Generation Partnership Project (3GPP) targets on latency and reliability requirements to successfully deliver delay-sensitive information. In 3GPP, the performance target for control plane latency is 10 ms, and for user plane latency it is 0.5 ms for downlink and uplink directions, separately.
Sun, H-H, Zhu, H, Ding, C & Guo, YJ 2018, 'Wideband Planarized Dual-Linearly-Polarized Dipole Antenna and Its Integration for Dual-Circularly-Polarized Radiation', IEEE Antennas and Wireless Propagation Letters, vol. 17, no. 12, pp. 2289-2293.
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© 2002-2011 IEEE. A planarized dual-linearly-polarized (dual-LP) antenna and an integrated dual-circularly-polarized (dual-CP) antenna are proposed in this letter. For the dual-LP antenna, two groups of dipoles are fed by two balun-included feed networks to achieve ±45° polarizations. The feed networks and the radiators are printed on two sides of a substrate, forming a fully planar structure. Taking advantage of its planar configuration, the dual-LP antenna is further integrated with a wideband coupler to realize dual-CP radiation. The coupler is bent and squeezed into the space between the radiators and the reflector, leading to a compact structure. Both the dual-LP antenna and the dual-CP antenna have very stable radiation performances across a wide operating band >66%.
Sutton, GJ, Liu, RP & Guo, YJ 2018, 'Delay and Reliability of Load-Based Listen-Before-Talk in LAA', IEEE Access, vol. 6, pp. 6171-6182.
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© 2013 IEEE. With the release of the 5 GHz unlicensed spectrum has emerged licensed-Assisted access, in which long-Term evolution (LTE) operators compete with Wi-Fi users for a share of the unlicensed spectrum so as to augment their licensed spectrum. Subsequently, there has been the need to develop a LTE channel access mechanism that enables harmonious coexistence between Wi-Fi and LTE. Load-based listen-before-Talk (LB-LBT) has been adopted as this LTE channel access mechanism by the 3rd Generation Partnership Project (3GPP). Theoretical modelling of LB-LBT schemes has focused on throughput and fair channel-Time sharing between Wi-Fi and LTE technologies. We explore a LB-LBT scheme that belongs to LBT category 4, as recommended by the 3GPP, and develop a model for the distribution of the medium access control (MAC) delays experienced by the Wi-Fi packets and LTE frames. The model, validated by simulations, reveals design insights that can be used to dynamically adjust the LB-LBT parameters not only to achieve channel-Time fairness, but also to guarantee MAC-delay bounds, with specified probability.
Sutton, GJ, Zeng, J, Liu, RP, Ni, W, Nguyen, DN, Jayawickrama, BA, Huang, X, Abolhasan, M & Zhang, Z 2018, 'Enabling Ultra-Reliable and Low-Latency Communications through Unlicensed Spectrum', IEEE Network, vol. 32, no. 2, pp. 70-77.
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© 2018 IEEE. In this article, we aim to address the question of how to exploit the unlicensed spectrum to achieve URLLC. Potential URLLC PHY mechanisms are reviewed and then compared via simulations to demonstrate their potential benefits to URLLC. Although a number of important PHY techniques help with URLLC, the PHY layer exhibits an intrinsic trade-off between latency and reliability, posed by limited and unstable wireless channels. We then explore MAC mechanisms and discuss multi-channel strategies for achieving low-latency LTE unlicensed band access. We demonstrate, via simulations, that the periods without access to the unlicensed band can be substantially reduced by maintaining channel access processes on multiple unlicensed channels, choosing the channels intelligently, and implementing RTS/CTS.
Takalkar, M, Xu, M, Wu, Q & Chaczko, Z 2018, 'A survey: facial micro-expression recognition', Multimedia Tools and Applications, vol. 77, no. 15, pp. 19301-19325.
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© 2017, Springer Science+Business Media, LLC. Facial expression recognition plays a crucial role in a wide range of applications of psychotherapy, security systems, marketing, commerce and much more. Detecting a macro-expression, which is a direct representation of an ‘emotion,’ is a relatively straight-forward task. Playing a pivotal role as macro-expressions, micro-expressions are more accurate indicators of a train of thought or even subtle, passive or involuntary thoughts. Compared to macro-expressions, identifying micro-expressions is a much more challenging research question because their time spans are narrowed down to a fraction of a second, and can only be defined using a broader classification scale. This paper is an all-inclusive survey-cum-analysis of the various micro-expression recognition techniques. We analyze the general framework for micro-expression recognition system by decomposing the pipeline into fundamental components, namely face detecting, pre-processing, facial feature detection and extraction, datasets, and classification. We discuss the role of these elements and highlight the models and new trends that are followed in their design. Moreover, we provide an extensive analysis of micro-expression recognition systems by comparing their performance. We also discuss the new deep learning features that can, in the near future, replace the hand-crafted features for facial micro-expression recognition. This survey has been developed, focusing on the methodologies applied, databases used, performance regarding recognition accuracy and comparing these to distil the gaps in the efficiencies, future scope, and research potentials. Through this survey, we intend to look into this problem and develop a comprehensive and efficient recognition scheme. This study allows us to identify open issues and to determine future directions for designing real-world micro-expression recognition systems.
Usman, M, Yang, N, Jan, MA, He, X, Xu, M & Lam, K-M 2018, 'A Joint Framework for QoS and QoE for Video Transmission over Wireless Multimedia Sensor Networks', IEEE Transactions on Mobile Computing, vol. 17, no. 4, pp. 746-759.
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© 2002-2012 IEEE. With the emergence of Wireless Multimedia Sensor Networks (WMSNs), the distribution of multimedia contents have now become a reality. Without proper management, the transmission of multimedia data over WMSNs affects the performance of networks due to excessive packet-drop. The existing studies on Quality of Service (QoS) mostly deal with simple Wireless Sensor Networks (WSNs) and as such do not account for an increasing number of sensor nodes and an increasing volume of data. In this paper, we propose a novel framework to support QoS in WMSNs along with a light-weight Error Concealment (EC) scheme. The EC schemes play a vital role to enhance Quality of Experience (QoE) by maintaining an acceptable quality at the receiving ends. The main objectives of the proposed framework are to maximize the network throughput and to cover-up the effects produced by dropped video packets. To control the data-rate, Scalable High efficiency Video Coding (SHVC) is applied at multimedia sensor nodes with variable Quantization Parameters (QPs). Multi-path routing is exploited to support real-time video transmission. Experimental results show that the proposed framework can efficiently adjust large volumes of video data under certain network distortions and can effectively conceal lost video frames by producing better objective measurements.
Vo, K, Pham, T, Nguyen, DN, Kha, HH & Dutkiewicz, E 2018, 'Subject-Independent ERP-Based Brain–Computer Interfaces', IEEE Transactions on Neural Systems and Rehabilitation Engineering, vol. 26, no. 4, pp. 719-728.
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Brain–computer interfaces (BCIs) are desirable for people to express their thoughts, especially those with profound disabilities in communication.
The classification of brain patterns for each different subject requires an extensively time-consuming learning stage specific to that person, in order to reach satisfactory
accuracy performance. The training session could also be
infeasible for disabled patients as they may not fully understand the training instructions. In this paper, we propose a
unified classification scheme based on ensemble classifier,
dynamic stopping, and adaptive learning. We apply
this scheme on the P300-based BCI, with the subjectindependent manner, where no learning session is required for new experimental users. According to our theoretical analysis and empirical results, the harmonized integration of these three methods can significantly boost up the average accuracy from 75.00% to 91.26%, while at the same
time reduce the average spelling time from 12.62 to 6.78 iterations, approximately to two-fold faster. The experiments were conducted on a large public dataset which had been used in other related studies. Direct comparisons between our work with the others’ are also reported in details.
Wang, N, Li, H-W, Ding, C, Shi, L-Y, Jia, H-Z, Ren, Z-D & Zhao, Z-Y 2018, 'A Double-Voltage-Controlled Effective Thermal Conductivity Model of Graphene for Thermoelectric Cooling', IEEE Transactions on Electron Devices, vol. 65, no. 3, pp. 1185-1191.
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© 1963-2012 IEEE. Graphene provides a new opportunity for thermoelectric study based on its unique heat transfer behavior controllable by a gate voltage. In this paper, an effective thermal conductivity model of graphene for thermoelectric cooling is proposed. The model is based on a double-voltage-control mechanism. According to the law of Fourier heat conduction, an effective thermal conductivity model of the proposed thermoelectric cooling device is derived taking a tunable external voltage into account. Then, a gate voltage is used which can change graphene's thermoelectric characteristics. To verify the correctness and effectiveness of the proposed model, a circuit simulation model using HSPICE is built based on the thermoelectric duality. The simulation results from HSPICE and the calculated results from the mathematic model show good agreements with each other. This paper provides a novel precisely controlling method for thermoelectric cooling.
Wang, TQ & Huang, X 2018, 'Fractional Reverse Polarity Optical OFDM for High Speed Dimmable Visible Light Communications', IEEE Transactions on Communications, vol. 66, no. 4, pp. 1565-1578.
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© 1972-2012 IEEE. In this paper, fractional reverse polarity optical orthogonal frequency division multiplexing (FRPO-OFDM) is studied to enable dimming compatible visible light communications. The scheme combines a layered asymmetrically clipped optical OFDM (ACO-OFDM) sequence with an information-carrying brightness control sequence (BCS) in the form of M -ary pulse position modulation. We derive the expressions of the FRPO-OFDM signal and its achievable brightness level, and develop an effective detector which can recover information from both sequences based on maximum likelihood detection. We show that when the detector is to be implemented, the use of multi-layer ACO-OFDM imposes strong periodicity on the BCS, which leads to a trade-off between spectral efficiency and brightness resolution for dimming control. It is shown that high spectral efficiency can be achieved with practical dimming requirements. Simulation results show that the extra information carried by the BCS can be decoded with extremely low bit error rate and thus has negligible impacts on the demodulation of the ACO-OFDM signal, when the system nonlinearity is not dominating.
Wang, TQ, Li, H & Huang, X 2018, 'Interference Cancellation for Layered Asymmetrically Clipped Optical OFDM With Application to Optical Receiver Design', Journal of Lightwave Technology, vol. 36, no. 11, pp. 2100-2113.
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© 1983-2012 IEEE. In this paper, we study a novel two-stage receiver to demodulate layered asymmetrically clipped optical orthogonal frequency division multiplexing for intensity modulation direct detection based visible light communications. Designed for avoiding the error propagation of the conventional receiver, the first stage of the receiver is a soft interference cancellation (SIC) module which evaluates the minimum mean square error (MMSE) estimates of the signals in different layers. For this stage, we derive the exact formula of the MMSE estimator, and compare the achieved mean square error and bit error rate (BER) with those of the existing simplified SIC receiver. We show that the estimation error in a layer has negligible impact on the design of estimators in the subsequent layers. Using the outputs of the SIC module, the second stage performs noise clipping to suppress the additive noise. For this stage, we present two schemes, the SIC-based iterative noise clipping (SIC-INC) and the SIC-based direct noise clipping (SIC-DNC). The simulation results show that SIC-INC can achieve BERs similar to those of the SIC-based diversity combining receiver with optimum combining coefficients. It is also shown that SIC-DNC outperforms the existing advanced receivers by up to 0.8 dB at the BER of 10{-4}.
Wang, W, Hoang, DT, Niyato, D, Wang, P & Kim, DI 2018, 'Stackelberg Game for Distributed Time Scheduling in RF-Powered Backscatter Cognitive Radio Networks', IEEE Transactions on Wireless Communications, vol. 17, no. 8, pp. 5606-5622.
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© 2002-2012 IEEE. In this paper, we study the transmission strategy adaptation problem in an RF-powered cognitive radio network, in which hybrid secondary users are able to switch between the harvest-then-transmit mode and the ambient backscatter mode for their communication with the secondary gateway. In the network, a monetary incentive is introduced for managing the interference caused by the secondary transmission with imperfect channel sensing. The sensing-pricing-transmitting process of the secondary gateway and the transmitters is modeled as a single-leader-multi-follower Stackelberg game. Furthermore, the follower sub-game among the secondary transmitters is modeled as a generalized Nash equilibrium problem with shared constraints. Based on our theoretical discoveries regarding the properties of equilibria in the follower sub-game and the Stackelberg game, we propose a distributed, iterative strategy searching scheme that guarantees the convergence to the Stackelberg equilibrium. The numerical simulations show that the proposed hybrid transmission scheme always outperforms the schemes with fixed transmission modes. Furthermore, the simulations reveal that the adopted hybrid scheme is able to achieve a higher throughput than the sum of the throughput obtained from the schemes with fixed transmission modes.
Wang, Y, Wang, Z, Jia, W, He, X & Jiang, M 2018, 'Joint Learning of Body and Part Representation for Person Re-Identification', IEEE Access, vol. 6, pp. 44199-44210.
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© 2013 IEEE. Person re-identification (ReID), aiming to identify people among multiple camera views, has attracted an increasing attention due to the potential of application in surveillance security. Large variations in subjects' postures, view angles, and illuminating conditions as well as non-ideal human detection significantly increase the difficulty of person ReID. Learning a robust metric for measuring the similarity between different person images is another under-addressed problem. In this paper, following the recent success of part-based models, in order to generate a discriminative and robust feature representation, we first propose to learn global and weighted local body-part features from pedestrian images. Then, in the training phase, angular loss and part-level classification loss are employed jointly as a similarity measure to train the network, which significantly improves the robustness of the resultant network against feature variance. Experimental results on several benchmark data sets demonstrate that our method outperforms the state-of-the-art methods.
Wang, Y, Zhang, J, Liu, Z, Wu, Q, Zhang, Z & Jia, Y 2018, 'Depth Super-Resolution on RGB-D Video Sequences With Large Displacement 3D Motion', IEEE Transactions on Image Processing, vol. 27, no. 7, pp. 3571-3585.
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© 1992-2012 IEEE. To enhance the resolution and accuracy of depth data, some video-based depth super-resolution methods have been proposed, which utilizes its neighboring depth images in the temporal domain. They often consist of two main stages: motion compensation of temporally neighboring depth images and fusion of compensated depth images. However, large displacement 3D motion often leads to compensation error, and the compensation error is further introduced into the fusion. A video-based depth super-resolution method with novel motion compensation and fusion approaches is proposed in this paper. We claim that 3D nearest neighboring field (NNF) is a better choice than using positions with true motion displacement for depth enhancements. To handle large displacement 3D motion, the compensation stage utilized 3D NNF instead of true motion used in the previous methods. Next, the fusion approach is modeled as a regression problem to predict the super-resolution result efficiently for each depth image by using its compensated depth images. A new deep convolutional neural network architecture is designed for fusion, which is able to employ a large amount of video data for learning the complicated regression function. We comprehensively evaluate our method on various RGB-D video sequences to show its superior performance.
Wang, Z & Piccardi, M 2018, 'Minimum-risk temporal alignment of videos', Multimedia Tools and Applications, vol. 77, no. 12, pp. 14891-14906.
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Temporal alignment of videos is an important requirement of tasks such as video comparison, analysis and classification. Most of the approaches proposed to date for video alignment leverage dynamic programming algorithms whose parameters are manually tuned. Conversely, this paper proposes a model that can learn its parameters automatically by minimizing a meaningful loss function over a given training set of videos and alignments. For learning, we exploit the effective framework of structural SVM and we extend it with an original scoring function that suitably scores the alignment of two given videos, and a loss function that quantifies the accuracy of a predicted alignment. The experimental results from four video action datasets show that the proposed model has been able to outperform a baseline and a state-of-the-art algorithm by a large margin in terms of alignment accuracy.
Wu, K, Ni, W, Su, T, Liu, RP & Guo, YJ 2018, 'Fast and Accurate Estimation of Angle-of-Arrival for Satellite-Borne Wideband Communication System', IEEE Journal on Selected Areas in Communications, vol. 36, no. 2, pp. 314-326.
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© 1983-2012 IEEE. Accurate estimation of angle-of-arrival (AoA) is critical to wideband satellite communications, but is susceptible to receive noises and can be ambiguous due to space/cost-effective hybrid antenna array designs with localized analog phased subarrays. As a matter of fact, there has yet to be an unambiguous estimator even for narrow-band systems. This paper proposes a new design of subarray-specific time-varying phase shifts, which enables unambiguous and noise-tolerant estimation of AoA in localized hybrid arrays. Particularly, the new phase shifts deliver deterministic phase changes in the cross-correlations of receive signals between subarrays, and enable the cross-correlations to be coherently accumulated across subarrays and sub-carriers to eliminate ambiguities and tolerate noises. Another important contribution of the paper is that we optimize the frequency interval for coherent accumulation across sub-carriers, leveraging between estimation errors, and accumulation gains. Evident from simulations, our approach is able to dramatically improve the estimation accuracy by orders of magnitudes with significantly reduced requirements of complexities and training symbols, as compared with the state of the art. The approach is robust against noises, with estimation errors asymptotically achieving a rigorously developed lower bound.
Wu, K, Ni, W, Su, T, Liu, RP & Guo, YJ 2018, 'Robust Unambiguous Estimation of Angle-of-Arrival in Hybrid Array With Localized Analog Subarrays', IEEE Transactions on Wireless Communications, vol. 17, no. 5, pp. 2987-3002.
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© 2018 IEEE. Hybrid array is able to leverage array gains, transceiver sizes, and costs for massive multiple-input-multiple-output systems in millimeter-wave frequencies. Challenges arise from the estimation of angle-of-arrival (AoA) in localized hybrid arrays, due to the array structure and the resultant estimation ambiguities and susceptibility to noises. This paper eliminates the ambiguities and enhances the tolerance to the noises based on our new discoveries. Particularly, by designing new subarray-specific time-varying phase shifts, we discover that the cross-correlations between the gains of consecutive subarrays have consistent signs except the strongest. This enables the cross-correlations to be deterministically calibrated and constructively combined for the noise-tolerant estimation of the propagation phase offset between adjacent subarrays. Given the phase offset, the AoA can be estimated unambiguously with few training symbols. We also derive a closed-form lower bound for the mean square error of AoA estimation. Corroborated by simulations, our approach is able to dramatically improve estimation accuracy by orders of magnitude while reducing complexity and training symbols, as compared to the state of the art. With the ambiguities eliminated, the estimation errors of our method asymptotically approach the lower bound, as training symbols increase.
Wu, L, Xu, M, Zhu, G, Wang, J & Rao, T 2018, 'Appearance features in Encoding Color Space for visual surveillance', Neurocomputing, vol. 308, pp. 21-30.
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© 2018 Elsevier B.V. Person re-identification and visual tracking are two important tasks in video surveillance. Many works have been done on appearance modeling for these two tasks. However, existing feature descriptors are mainly constructed on three-channel color spaces, such like RGB, HSV and XYZ. These color spaces somehow enable meaningful representation for color, yet may lack distinctiveness for real-world tasks. In this paper, we propose a multi-channel Encoding Color Space (ECS), and consider the color distinction with the design of image feature descriptor. In order to overcome the illumination variation and shape deformation, we design features on the basis of the Encoding Color Space and Histogram of Oriented Gradient (HOG), which enables rich color-gradient characteristics. Additionally, we extract Second Order Histogram (SOH) on the descriptor constructed to capture abstract information with layout constrains. Exhaustive experiments are performed on datasets VIPeR, CAVIAR, CUHK01 and Visual Tracking Benchmark. Experimental results on these datasets show that our feature descriptors could achieve promising performance.
Xia, H, Zhuge, R, Li, H, Song, S, Jiang, F & Xu, M 2018, 'Single Image Rain Removal via a Simplified Residual Dense Network', IEEE Access, vol. 6, pp. 66522-66535.
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© 2013 IEEE. The single-image rain removal problem has attracted tremendous interests within the deep learning domains. Although deep learning based de-raining methods outperform many conventional methods, there are still unresolved issues in regards to improving the performance. In this paper, we propose a simplified residual dense network (SRDN) to improve the de-raining performance and cut down the computation time. Inspired by the image processing domain knowledge that a rainy image can be decomposed into a base (low-pass) layer and a detail (high-pass) layer, we train our network by directly learning the residual between the detail layer of rainy images and the detail layer of clean images. It can both significantly reduce the mapping range from input to output and easily employ the image enhancement operation to handle the heavy rain with hazy looks. Instead of designing a deeper network structure to increase the learning ability of network, we propose a simplified dense block to explore more effective information between layers and, hence, reduce the computation time of network. Experiments on both synthetic and real-world images demonstrate that our SRDN network can achieve competitive results in comparison with the benchmarked and conventional approaches for single-image rain removal.
Xie, H, He, Z & Veitch, D 2018, 'Disturbance observer-based visual servoing for multirotor unmanned aerial vehicles', at - Automatisierungstechnik, vol. 66, no. 3, pp. 258-267.
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Abstract This paper presents a disturbance observer based input saturated visual servoing law for a quadrotor unmanned aerial vehicle (UAV). The controller regulates the 4D relative pose, i. e., 3D translational and yaw motion, between the vehicle and a planar horizontal visual target in an environment with external disturbances. A feedforward control is used to compensate the lumped disturbance consisting of both system uncertainties and external disturbances. The feedback control part is based on a nested saturation control, which is used to bound the orientation of the UAV and therefore helps to keep the visual target in the camera’s field of view. Simulation results are provided to demonstrate controller performance.
Xu, KD, Li, M, Liu, Y, Yang, Y & Liu, QH 2018, 'Design of Triplexer Using E-Stub-Loaded Composite Right-/Left-Handed Resonators and Quasi-Lumped Impedance Matching Network', IEEE Access, vol. 6, pp. 18814-18821.
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© 2013 IEEE. A compact triplexer based on E-stub-loaded composite right-/left-handed (ESL-CRLH) resonators with quasi-lumped impedance matching network is presented in this paper. The equivalent circuit model of the ESL-CRLH resonator is presented first and its left-/right-handed capacitance/inductance elements are fully derived. Then, a quasi-lumped impedance matching circuit is designed to connect the three ESL-CRLH resonator based filter channels for the triplexer construction. Finally, the designed triplexer obtains high isolations among the ports and low in-band insertion losses of the three filter channels centered at 1.86, 2.41, and 3.25 GHz, of which a miniaturized layout has been realized. Good agreement between the simulated and measured results can be observed to validate the design idea.
Xuan, J, Lu, J, Zhang, G, Xu, RYD & Luo, X 2018, 'Doubly Nonparametric Sparse Nonnegative Matrix Factorization Based on Dependent Indian Buffet Processes', IEEE Transactions on Neural Networks and Learning Systems, vol. 29, no. 5, pp. 1835-1849.
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© 2012 IEEE. Sparse nonnegative matrix factorization (SNMF) aims to factorize a data matrix into two optimized nonnegative sparse factor matrices, which could benefit many tasks, such as document-word co-clustering. However, the traditional SNMF typically assumes the number of latent factors (i.e., dimensionality of the factor matrices) to be fixed. This assumption makes it inflexible in practice. In this paper, we propose a doubly sparse nonparametric NMF framework to mitigate this issue by using dependent Indian buffet processes (dIBP). We apply a correlation function for the generation of two stick weights associated with each column pair of factor matrices while still maintaining their respective marginal distribution specified by IBP. As a consequence, the generation of two factor matrices will be columnwise correlated. Under this framework, two classes of correlation function are proposed: 1) using bivariate Beta distribution and 2) using Copula function. Compared with the single IBP-based NMF, this paper jointly makes two factor matrices nonparametric and sparse, which could be applied to broader scenarios, such as co-clustering. This paper is seen to be much more flexible than Gaussian process-based and hierarchial Beta process-based dIBPs in terms of allowing the two corresponding binary matrix columns to have greater variations in their nonzero entries. Our experiments on synthetic data show the merits of this paper compared with the state-of-the-art models in respect of factorization efficiency, sparsity, and flexibility. Experiments on real-world data sets demonstrate the efficiency of this paper in document-word co-clustering tasks.
Xue, R, Huang, S, Luo, X, Jiang, D & Da Xu, RY 2018, 'Semantic emotion-topic model based social emotion mining', Journal of Web Engineering, vol. 17, no. 1-2, pp. 73-92.
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With the booming of social media users, more and more short texts with emotion labels appear, which contain users' rich emotions and opinions about social events or enterprise products. Social emotion mining on social media corpus can help government or enterprise make their decisions. Emotion mining models involve statistical-based and graph-based approaches. Among them, the former approaches are more popular, e.g. Latent Dirichlet Allocation (LDA)-based Emotion Topic Model. However, they are suffering from low retrieval performance, such as the bad accuracy and the poor interpretability, due to them only considering the bag-of-words or the emotion labels in social media corpus. In this paper, we propose a LDA-based Semantic Emotion-Topic Model (SETM) combining emotion labels and inter-word relations to enhance the retrieval performance of social emotion mining result. The performance influence of four factors on SETM are considered, i.e., association relations, computing time, topic number and semantic interpretability. Experimental results show that the accuracy of our proposed model is 0.750, compared with 0.606, 0.663 and 0.680 of Emotion Topic Model (ETM), Multi-label Supervised Topic Model (MSTM) and Sentiment Latent Topic Model (SLTM) respectively. Besides, the computing time of our model is reduced by 87.81% through limiting word frequency, and its accuracy is 0.703, compared with 0.501, 0.648 and 0.642 of the above baseline methods. Thus, the proposed model has broad prospects in social emotion mining area.
Yan, B, Zhao, Q, Wang, Z & Zhang, JA 2018, 'Adaptive decomposition-based evolutionary approach for multiobjective sparse reconstruction', Information Sciences, vol. 462, pp. 141-159.
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© 2018 Elsevier Inc. This paper aims at solving the sparse reconstruction (SR) problem via a multiobjective evolutionary algorithm. Existing multiobjective evolutionary algorithms for the SR problem have high computational complexity, especially in high-dimensional reconstruction scenarios. Furthermore, these algorithms focus on estimating the whole Pareto front rather than the knee region, thus leading to limited diversity of solutions in knee region and waste of computational effort. To tackle these issues, this paper proposes an adaptive decomposition-based evolutionary approach (ADEA) for the SR problem. Firstly, we employ the decomposition-based evolutionary paradigm to guarantee a high computational efficiency and diversity of solutions in the whole objective space. Then, we propose a two-stage iterative soft-thresholding (IST)-based local search operator to improve the convergence. Finally, we develop an adaptive decomposition-based environmental selection strategy, by which the decomposition in the knee region can be adjusted dynamically. This strategy enables to focus the selection effort on the knee region and achieves low computational complexity. Experimental results on simulated signals, benchmark signals and images demonstrate the superiority of ADEA in terms of reconstruction accuracy and computational efficiency, compared to five state-of-the-art algorithms.
Yang, T, Ding, C, Ziolkowski, RW & Guo, YJ 2018, 'Circular hole ENZ photonic crystal fibers exhibit high birefringence', Optics Express, vol. 26, no. 13, pp. 17264-17264.
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© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement —A novel photonic crystal fiber (PCF) design that yields very high birefringence is proposed and analyzed. Its significantly enhanced birefringence is achieved by filling selected air holes in the cladding with an epsilon-near-zero (ENZ) material. Extensive simulation results of this asymmetric material distribution in the lower THz range demonstrate that the reported PCF has a birefringence above 0.1 and a loss below 0.01 cm−1 over a wide band of frequencies. Moreover, it exhibits near zero dispersion at 0.75 THz for both the X- and Y-polarization modes and a birefringence equal to 0.28. This THz PCF is then scaled successfully to optical frequencies. While the high birefringence is maintained, this optical PCF has a very high loss in its Y-polarization mode and, consequently, yields single-polarization single-mode (SPSM) propagation, exhibiting near zero dispersion at the optical telecom wavelength of 1.55 μm. The ideal ENZ materials used for these conceptual models are replaced with realistic ones for both the THz and optical PCF designs. With the currently available ENZ materials, the realistic PCFs still have a high birefringence, but with higher losses compared to the idealized results. Future developments of ENZ materials that achieve lower loss properties will mitigate this issue in any frequency band of high interest.
Yang, T, Ding, C, Ziolkowski, RW & Jay Guo, Y 2018, 'A Scalable THz Photonic Crystal Fiber With Partially-Slotted Core That Exhibits Improved Birefringence and Reduced Loss', Journal of Lightwave Technology, vol. 36, no. 16, pp. 3408-3417.
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© 1983-2012 IEEE. A photonic crystal fiber (PCF) based on high resistivity silicon is reported that exhibits high birefringence, low loss, and flat dispersion characteristics across a wide bandwidth in the THz regime. Except for the center region, which remains the background dielectric, its core is occupied by a set of rectangular air slots. The material and configuration lead to high birefringence and low loss. The simulation results, which include the material losses, indicate that a birefringence value of 0.82 and a total loss of 0.011 cm-1, including the effective material loss and confinement losses, are achieved at 1.0 THz. These values are a factor of ten times higher and four times lower, respectively, than many recent designs. The numerical analyses also demonstrate that the reported PCF can be scaled to any desired portion of the THz regime, while maintaining a similar birefringence, simply by changing the lattice constant. This 'scalable' characteristic is shown to be applicable to other PCF designs. It could facilitate a novel way of testing THz fibers, i.e., it suggests that one only needs to test the preform to validate the performance of the fiber at higher frequencies. This outcome would significantly reduce the design complexity and the costs of PCF testing.
Yang, W, Li, J, Zheng, H & Xu, RYD 2018, 'A Nuclear Norm Based Matrix Regression Based Projections Method for Feature Extraction', IEEE Access, vol. 6, pp. 7445-7451.
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© 2013 IEEE. In the traditional graph embedding framework, the graph is usually built by k-NN or r-ball. Since it is difficult to manually set the parameters k and r in the high-dimensional space, sparse representation-based methods are usually introduced to automatically build the graphs. In recent years, nuclear norm-based matrix regression (NMR) has been proposed for face recognition using the low rank structural information (i.e., the image matrix-based error model). Inspired by NMR, we give a NMR-based projections (NMRP) method for feature extraction and recognition. The experiments on FERET and extended Yale B face databases show that NMR can be used to build the graph while NMRP is an effective feature extraction method.
Yang, X, Qin, P-Y, Liu, Y, Yin, Y-Z & Guo, YJ 2018, 'Analysis and Design of a Broadband Multifeed Tightly Coupled Patch Array Antenna', IEEE Antennas and Wireless Propagation Letters, vol. 17, no. 2, pp. 217-220.
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© 2017 IEEE. In this letter, a multifeed tightly coupled patch array antenna capable of broadband operation is analyzed and designed. First, an antenna array composed of infinite elements with each element excited by a feed is proposed. To produce specific polarized radiation efficiently, a new patch element is proposed, and its characteristics are studied based on a 2-port network model. Full-wave simulation results show that the infinite antenna array exhibits both a high efficiency and desirable radiation pattern in a wide frequency band (10 dB bandwidth) from 1.91 to 5.35 GHz (94.8%). Second, to validate its outstanding performance, a realistic finite 4 × 4 antenna prototype is designed, fabricated, and measured in our laboratory. The experimental results agree well with simulated ones, where the frequency bandwidth (VSWR < 2) is from 2.5 to 3.8 GHz (41.3%). The inherent compact size, light weight, broad bandwidth, and good radiation characteristics make this array antenna a promising candidate for future communication and advanced sensing systems.
Yang, Y & Zhu, X 2018, 'A Wideband Reconfigurable Antenna With 360° Beam Steering for 802.11ac WLAN Applications', IEEE Transactions on Antennas and Propagation, vol. 66, no. 2, pp. 600-608.
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© 1963-2012 IEEE. A novel 360° beam steering patch antenna with parasitic elements is presented in this paper. The designed antenna consists of a radiating patch and six parasitic elements, each of which is connected through a group of shorting vias controlled by p-i-n diode switches. By switching on the desired groups of the shorting vias, the electric field distribution inside substrate cavity appears at the desired beam direction. Rotationally switching on the groups of the shorting vias, the performance of 360° beam scanning is realized. To further understand operating mechanism, the antenna is modeled with equivalent circuit in terms of the on and off status of a sector of the antenna, which can be used as a design guide for shorting-vias-controlled reconfigurable microstrip patch antennas. The fabricated antenna achieves a bandwidth of 14.5%, a peak gain of 10 dBi, and the efficiency of 80.5%. The achieved beamwidths are 42° and 97° in azimuth and elevation planes, respectively. With an ability of being steered around zenith axis at six directions, the scanned beam range covers the entire 360°. The physical dimension is only 2.5 λg for the size and 0.5λg for the profile. This antenna operates from 5.1 to 5.9 GHz and has significant meaning in the IEEE 802.11ac wireless local area network applications due to its capabilities of generating 360° steered beams.
Yang, Y, Li, Z, Wang, S, Chen, X, Wang, J & Guo, YJ 2018, 'Miniaturized High-Order-Mode Dipole Antennas Based on Spoof Surface Plasmon Polaritons', IEEE Antennas and Wireless Propagation Letters, vol. 17, no. 12, pp. 2409-2413.
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© 2002-2011 IEEE. A miniaturization method for antennas is developed based on spoof surface plasmon polaritons (SSPPs). With a large phase constant on the SSPPs transmission line, the guide wavelength can be dramatically reduced, with great potential on the miniaturization application of antennas. By introducing a miniaturization factor M, the relationship between M and the phase constant on the SSPPs dipole is studied, providing guidance to the design of miniaturized SSPPs dipoles. Then, SSPPs dipoles operating at 2.4 GHz are designed, including both the odd-And even-resonance dipoles. Simple feeding structures are developed for the odd-And even-resonance dipoles, respectively, and particularly for the even-resonance mode to realize a transition from 50 Ω to very large input impedance of the dipole. The miniaturized SSPPs dipoles operating at the 1st, 2nd, 3rd, and 4th modes are fabricated. The measured reflection coefficients and radiation patterns show good agreements with the simulated results. It can be concluded that the dipole lengths for these modes are reduced by 8%, 11%, 10%, and 13%, respectively, compared with the conventional printed dipoles on the same substrate.
Yang, Y, Zhu, H, Zhu, X & Xue, Q 2018, 'A Low-Loss Bandpass Filter using Edge-Coupled Resonator With Capacitive Feeding in (Bi)-CMOS Technology', IEEE Electron Device Letters, vol. 39, no. 6, pp. 787-790.
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© 1980-2012 IEEE. In this Letter, a flexible approach for low-loss on-chip bandpass filter (BPF) design in CMOS technology is presented. The proposed approach takes the advantages of a combination of an edge-coupled electromagnetic structure, namely resonator, and a pair of metal-insulator-metal capacitors for BPF implementation. To demonstrate the insight of the approach, the designed resonator is analyzed in details by means of a simplified equivalent LC-circuit model. Then, the impact on the BPF design due to the variations of the feeding capacitance is investigated. To prove the concept, both the resonator and BPF are fabricated in a standard 0.13- μ m CMOS technology. The measured results show that the designed resonator can generate a notch with 20-dB attenuation at 59.4 GHz, while the BPF has a center frequency of 35.4 GHz with an insertion loss of 1.7 dB. The chip size of both devices, excluding the test pads, is only 0.039 mm2 (0.15 × 0.26 mm2).
Yang, Y, Zhu, X & Xue, Q 2018, 'Design of an Ultracompact On-Chip Bandpass Filter Using Mutual Coupling Technique', IEEE Transactions on Electron Devices, vol. 65, no. 3, pp. 1087-1093.
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© 1963-2012 IEEE. In this paper, design of an ultracompact bandpass filter (BPF) in GaAs technology without compromising its electrical performance is investigated by means of both theoretical analysis and electromagnetic simulation. In particular, the relationship between the external quality factor and the coupling coefficient of the second-order BPF is formulized to better understand the principle of the mutual coupling effect. To prove the concept, the designed filter is implemented in a commercial 0.1-μm GaAs technology. A step-by-step design guideline is elaborated. The BPF has not only the merits of ultracompactness, but also remarkable insertion loss (IL) compared with other state-of-The-Art on-chip designs. The measurement results show that the 1-dB bandwidth of the BPF is from 28 to 36 GHz, while the IL is less than 1 dB at 29.5 GHz. In addition, more than 40-dB rejection is achieved from 56 to 69 GHz. The size of the filter is only 230 × 280 μm2, excluding the pads, which is equivalent to 0.074 × 0.09 λg μm2} at 28 GHz. To the best of our knowledge, the proposed design is known to be the most compact one in the open literature using GaAs technologies.
Yuan, W, Wu, N, Yan, C, Li, Y, Huang, X & Hanzo, L 2018, 'A Low-Complexity Energy-Minimization-Based SCMA Detector and Its Convergence Analysis', IEEE Transactions on Vehicular Technology, vol. 67, no. 12, pp. 12398-12403.
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© 2018 IEEE. Sparse code multiple access (SCMA) has emerged as a promising non-orthogonal multiple access technique for the next-generation wireless communication systems. Since the signal of multiple users is mapped to the same resources in SCMA, its detection imposes a higher complexity than that of the orthogonal schemes, where each resource slot is dedicated to a single user. In this paper, we propose a low-complexity receiver for SCMA systems based on the radical variational free energy framework. By exploiting the pairwise structure of the likelihood function, the Bethe approximation is utilized for estimating the data symbols. The complexity of the proposed algorithm only increases linearly with the number of users, which is much lower than that of the maximum a posteriori detector associated with exponentially increased complexity. Furthermore, the convergence of the proposed algorithm is analyzed, and its convergence conditions are derived. Simulation results demonstrate that the proposed receiver is capable of approaching the error probability performance of the conventional message-passing-based receiver.
Yuan, X, Feng, Z, Xu, W, Ni, W, Zhang, JA, Wei, Z & Liu, RP 2018, 'Capacity Analysis of UAV Communications: Cases of Random Trajectories', IEEE Transactions on Vehicular Technology, vol. 67, no. 8, pp. 7564-7576.
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© 1967-2012 IEEE. This paper analyzes the link capacity between autonomous unmanned aerial vehicles (UAVs) with random three-dimensional (3-D) trajectories. This is distinctively different from existing works typically under the assumption of either two-dimensional (2-D) or deterministic trajectories, and particularly interesting to applications such as surveillance and air combat. The key idea is that we geometrically derive the probability distributions of the UAV-to-UAV (U2U) distances which, by exploiting the Jensen's inequality, can be translated to the closed-form bounds for the capacity between UAVs, and between UAVs and ground stations. Another important aspect is that we extrapolate the idea to dense UAV networks, and analyze the impact of network densification, imperfect channel state information, and interference from ground transmitters on the capacity. Corroborated by simulations, our analysis shows that a U2U link with random 2-D trajectories is superior in terms of capacity due to its short average link distance. It is also revealed that a UAV-to-ground link can incur substantially lower capacity than a U2U link even in the case the 3-D coverage of the UAVs is the same, as the result of its longer average link length.
Zeng, J, Lv, T, Liu, RP, Su, X, Peng, M, Wang, C & Mei, J 2018, 'Investigation on Evolving Single-Carrier NOMA Into Multi-Carrier NOMA in 5G', IEEE Access, vol. 6, pp. 48268-48288.
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© 2013 IEEE. Non-orthogonal multiple access (NOMA) is one promising technology, which provides high system capacity, low latency, and massive connectivity, to address several challenges in the fifth-generation wireless systems. In this paper, we first reveal that the NOMA techniques have evolved from single-carrier NOMA (SC-NOMA) into multi-carrier NOMA (MC-NOMA). Then, we comprehensively investigated on the basic principles, enabling schemes and evaluations of the two most promising MC-NOMA techniques, namely sparse code multiple access (SCMA) and pattern division multiple access (PDMA). Meanwhile, we consider that the research challenges of SCMA and PDMA might be addressed with the stimulation of the advanced and matured progress in SC-NOMA. Finally, yet importantly, we investigate the emerging applications, and point out the future research trends of the MC-NOMA techniques, which could be straightforwardly inspired by the various deployments of SC-NOMA.
Zeng, J, Peng, J, Liu, RP & Su, X 2018, 'Comments on “Cross-Tier Cooperation for Optimal Resource Utilization in Ultra-Dense Heterogeneous Networks”', IEEE Transactions on Vehicular Technology, vol. 67, no. 11, pp. 11307-11308.
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© 2018 IEEE. Two adaptive dedicated channel allocation algorithms, namely dynamic dedicated channel partitioning (D2CP) and dynamic dedicated channel partitioning with cooperation (D2CP-C), were proposed in [1] to improve the system throughput of ultra-dense networks (UDN). However, due to the incorrect use of the geometric-arithmetic mean inequality theorem, the average system throughput could not be guaranteed to be optimal. In this letter, we study the proposed D2CP and D2CP-C algorithms in UDN and deduce the average system throughput. Consequently, we prove that the equal resource allocation strategy proposed in [1] is strictly not optimal.
Zha, X, Ni, W, Wang, X, Liu, RP, Guo, YJ, Niu, X & Zheng, K 2018, 'The Impact of Link Duration on the Integrity of Distributed Mobile Networks', IEEE Transactions on Information Forensics and Security, vol. 13, no. 9, pp. 2240-2255.
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© 2005-2012 IEEE. A major challenge in distributed mobile networks is network integrity, resulting from short link duration and severe transmission collisions. This paper analyzes the impact of link duration and transmission collisions on a range of on-the-fly authentication protocols, which operate based on predistributed keys and can instantly verify and forward messages. All unexpired messages within a link duration can be verified retrospectively, once the keys are matched on-the-air. We develop a new general 4D Markov model which, apart from the first three dimensions modeling a cycle of the protocols, is able to unprecedentedly capture unexpired messages between cycles in the fourth dimension. Validated by simulation, our analysis reveals that the on-the-fly authentication is efficient under short link duration, but is susceptible to transmission collisions. The authentication requires holistic cross-layer designs of retransmission and rekeying. The proposed model is able to facilitate the design of the protocol parameters, which allows the protocols to significantly outperform the state of the art.
Zhang, G, Piccardi, M & Borzeshi, EZ 2018, 'Sequential Labeling With Structural SVM Under Nondecomposable Losses', IEEE Transactions on Neural Networks and Learning Systems, vol. 29, no. 9, pp. 4177-4188.
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IEEE Sequential labeling addresses the classification of sequential data, which are widespread in fields as diverse as computer vision, finance, and genomics. The model traditionally used for sequential labeling is the hidden Markov model (HMM), where the sequence of class labels to be predicted is encoded as a Markov chain. In recent years, HMMs have benefited from minimum-loss training approaches, such as the structural support vector machine (SSVM), which, in many cases, has reported higher classification accuracy. However, the loss functions available for training are restricted to decomposable cases, such as the 0-1 loss and the Hamming loss. In many practical cases, other loss functions, such as those based on the F & #x2081; measure, the precision/recall break-even point, and the average precision (AP), can describe desirable performance more effectively. For this reason, in this paper, we propose a training algorithm for SSVM that can minimize any loss based on the classification contingency table, and we present a training algorithm that minimizes an AP loss. Experimental results over a set of diverse and challenging data sets (TUM Kitchen, CMU Multimodal Activity, and Ozone Level Detection) show that the proposed training algorithms achieve significant improvements of the F & #x2081; measure and AP compared with the conventional SSVM, and their performance is in line with or above that of other state-of-the-art sequential labeling approaches.
Zhang, JA, Huang, X, Guo, YJ, Yuan, J & Jr, RWH 2018, 'Multibeam for Joint Communication and Sensing Using Steerable Analog Antenna Arrays', IEEE Transactions on Vehicular Technology,2019, vol. 68, no. 1, pp. 671-685.
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Beamforming has great potential for joint communication and sensing (JCAS),which is becoming a demanding feature on many emerging platforms such asunmanned aerial vehicles and smart cars. Although beamforming has beenextensively studied for communication and radar sensing respectively, itsapplication in the joint system is not straightforward due to differentbeamforming requirements by communication and sensing. In this paper, wepropose a novel multibeam framework using steerable analog antenna arrays,which allows seamless integration of communication and sensing. Different toconventional JCAS schemes that support JCAS using a single beam, our frameworkis based on the key innovation of multibeam technology: providing fixed subbeamfor communication and packet-varying scanning subbeam for sensing,simultaneously from a single transmitting array. We provide a systemarchitecture and protocols for the proposed framework, complying well withmodern packet communication systems with multicarrier modulation. We alsopropose low-complexity and effective multibeam design and generation methods,which offer great flexibility in meeting different communication and sensingrequirements. We further develop sensing parameter estimation algorithms usingconventional digital Fourier transform and 1D compressive sensing techniques,matching well with the multibeam framework. Simulation results are provided andvalidate the effectiveness of our proposed framework, beamforming designmethods and the sensing algorithms.
Zhang, T, Bao, J, Cai, Z, Yang, Y, Zhu, H, Zhu, X & Dutkiewicz, E 2018, 'A <inline-formula> <tex-math notation='LaTeX'>$C$ </tex-math> </inline-formula>-Band Compact Wideband Bandpass Filter With High Selectivity and Improved Return Loss', IEEE Microwave and Wireless Components Letters, vol. 28, no. 9, pp. 777-779.
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© 2001-2012 IEEE. In this letter, a C-band compact wideband bandpass filter (BPF) with high selectivity and improved return loss (RL) is proposed. Two pairs of short-circuited stubs are employed on a transmission-line model to generate three transmission poles and two transmission zeros (TZs), where the odd-and even-mode analysis is used to analyze the resonant frequencies of the BPF. By applying the transversal signal-interference technique, two additional TZs can be generated in the upper and lower stopbands, respectively. The measured results show that the 3-dB fractional bandwidth is 62.8% at the center frequency of 5 GHz. The RL and the insertion loss within the passband are better than 22 and 0.6 dB, respectively. Moreover, the roll-off rate is up to 100 dB/GHz.
Zhang, T, Gao, X, Du, J & Guo, YJ 2018, 'Full EM Design Method For HTS MMIC Josephson Mixers', IEEE Transactions on Applied Superconductivity, vol. 28, no. 4, pp. 1-5.
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© 2002-2011 IEEE. We report the full electromagnetic (EM) design and simulation method, and applied it to develop a 34-GHz high-temperature superconducting (HTS) microwave monolithic integrated circuit Josephson mixer. The mixer is modeled in EM simulation software, high-frequency simulation structural simulator, with the junction area modeled as an excitation port with frequency-dependent impedance. Impedance matching between the junction and RF/IF ports is then optimized accordingly. Module design is carried out for the optimized HTS Josephson mixer, and the cavity resonance issue is investigated and eliminated. The HTS mixer module was experimentally developed and measured to verify the simulation. The measured frequency response of the conversion gain agrees with the simulation results of combined RF and IF transmission loss.
Zhang, T, Jia, W, Gong, C, Sun, J & Song, X 2018, 'Semi-supervised dictionary learning via local sparse constraints for violence detection', Pattern Recognition Letters, vol. 107, pp. 98-104.
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© 2017 Elsevier B.V. In this paper, we propose a novel semi-supervised learning framework for violence detection in video surveillance. With this framework, a classifier which distinguishes violent behavior from normal behavior can be trained using inexpensive unlabeled data with the assistance of human operators. Our approach can learn a single dictionary and a predictive linear classifier jointly. Specifically, we integrate the reconstruction error of labeled and unlabeled data, representation constraints and the coefficient incoherence into an objective function for dictionary learning, which enhances the representative and discriminative power of the established dictionary. This has contributed to that the dictionary and the classifier learned from the labeled set yield very small generalization error on unseen data. Experimental results on benchmark datasets have demonstrated the effectiveness of our approach in violence detection.
Zhang, T, Li, J, Jia, W, Sun, J & Yang, H 2018, 'Fast and robust occluded face detection in ATM surveillance', Pattern Recognition Letters, vol. 107, pp. 33-40.
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© 2017 Elsevier B.V. Crimes with respect to ATMs (Automatic Teller Machines) have attracted more and more attention, where criminals deliberately cover their faces in order to avoid being identified. This paper proposes a fast and robust face occlusion detection algorithm for ATM surveillance, which is demonstrated to be effective and efficient to handle arbitrarily occluded faces. In this algorithm, we innovatively propose to make use of the Omega shape formed by the head and shoulder of the person for head localization to tackle severe face occlusion. For this purpose, we first construct a novel energy function for elliptical head contour detection. Then, we develop a fast and robust head tracking algorithm, which utilizes the gradient and shape cues in a Bayesian framework. Lastly, to verify whether a detected head is occluded or not, we propose to fuse information from both skin color and face structure using the AdaBoost algorithm. Experimental results on real world data show that our proposed algorithm can achieve 98.64% accuracy on face detection and 98.56% accuracy on face occlusion detection, even though there are severe occlusions in faces, at a speed of up to 12 frames per second.
Zhang, T, Zou, J & Jia, W 2018, 'Fast and robust road sign detection in driver assistance systems', Applied Intelligence, vol. 48, no. 11, pp. 4113-4127.
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© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Road sign detection plays a critical role in automatic driver assistance systems. Road signs possess a number of unique visual qualities in images due to their specific colors and symmetric shapes. In this paper, road signs are detected by a two-level hierarchical framework that considers both color and shape of the signs. To address the problem of low image contrast, we propose a new color visual saliency segmentation algorithm, which uses the ratios of enhanced and normalized color values to capture color information. To improve computation efficiency and reduce false alarm rate, we modify the fast radial symmetry transform (RST) algorithm, and propose to use an edge pairwise voting scheme to group feature points based on their underlying symmetry in the candidate regions. Experimental results on several benchmarking datasets demonstrate the superiority of our method over the state-of-the-arts on both efficiency and robustness.
Zhang, X, Lin, J, Chen, Z, Sun, F, Zhu, X & Fang, G 2018, 'An Efficient Neural-Network-Based Microseismic Monitoring Platform for Hydraulic Fracture on an Edge Computing Architecture', Sensors, vol. 18, no. 6, pp. 1828-1828.
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© 2018 by the authors. Licensee MDPI, Basel, Switzerland. Microseismic monitoring is one of the most critical technologies for hydraulic fracturing in oil and gas production. To detect events in an accurate and efficient way, there are two major challenges. One challenge is how to achieve high accuracy due to a poor signal-to-noise ratio (SNR). The other one is concerned with real-time data transmission. Taking these challenges into consideration, an edge-computing-based platform, namely Edge-to-Center LearnReduce, is presented in this work. The platform consists of a data center with many edge components. At the data center, a neural network model combined with convolutional neural network (CNN) and long short-term memory (LSTM) is designed and this model is trained by using previously obtained data. Once the model is fully trained, it is sent to edge components for events detection and data reduction. At each edge component, a probabilistic inference is added to the neural network model to improve its accuracy. Finally, the reduced data is delivered to the data center. Based on experiment results, a high detection accuracy (over 96%) with less transmitted data (about 90%) was achieved by using the proposed approach on a microseismic monitoring system. These results show that the platform can simultaneously improve the accuracy and efficiency of microseismic monitoring.
Zhang, X, Lv, T, Ni, W, Cioffi, JM, Beaulieu, NC & Guo, YJ 2018, 'Energy-Efficient Caching for Scalable Videos in Heterogeneous Networks', IEEE Journal on Selected Areas in Communications, vol. 36, no. 8, pp. 1802-1815.
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© 1983-2012 IEEE. By suppressing repeated content deliveries, wireless caching has the potential to substantially improve the energy efficiency (EE) of the fifth-generation communication networks. In this paper, we propose two novel energy-efficient caching schemes in heterogeneous networks, namely, scalable video coding (SVC)-based fractional caching and SVC-based random caching, which can provide on-demand video services with different perceptual qualities. We derive the expressions for successful transmission probabilities and ergodic service rates. Based on the derivations and the established power consumption models, the EE maximization problems are formulated for the two proposed caching schemes. By taking logarithmic approximations of the l0-norm, the problems are efficiently solved by the standard gradient projection method. Numerical results validate the theoretical analysis and demonstrate the superiority of our proposed caching schemes, compared to three benchmark strategies.
Zhang, Z, Chen, J, Wu, Q & Shao, L 2018, 'GII Representation-Based Cross-View Gait Recognition by Discriminative Projection With List-Wise Constraints', IEEE Transactions on Cybernetics, vol. 48, no. 10, pp. 2935-2947.
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© 2017 IEEE. Remote person identification by gait is one of the most important topics in the field of computer vision and pattern recognition. However, gait recognition suffers severely from the appearance variance caused by the view change. It is very common that gait recognition has a high performance when the view is fixed but the performance will have a sharp decrease when the view variance becomes significant. Existing approaches have tried all kinds of strategies like tensor analysis or view transform models to slow down the trend of performance decrease but still have potential for further improvement. In this paper, a discriminative projection with list-wise constraints (DPLC) is proposed to deal with view variance in cross-view gait recognition, which has been further refined by introducing a rectification term to automatically capture the principal discriminative information. The DPLC with rectification (DPLCR) embeds list-wise relative similarity measurement among intraclass and inner-class individuals, which can learn a more discriminative and robust projection. Based on the original DPLCR, we have introduced the kernel trick to exploit nonlinear cross-view correlations and extended DPLCR to deal with the problem of multiview gait recognition. Moreover, a simple yet efficient gait representation, namely gait individuality image (GII), based on gait energy image is proposed, which could better capture the discriminative information for cross view gait recognition. Experiments have been conducted in the CASIA-B database and the experimental results demonstrate the outstanding performance of both the DPLCR framework and the new GII representation. It is shown that the DPLCR-based cross-view gait recognition has outperformed the-state-of-the-art approaches in almost all cases under large view variance. The combination of the GII representation and the DPLCR has further enhanced the performance to be a new benchmark for cross-view gait recognition.
Zhao, J, Mao, X & Zhang, J 2018, 'Learning deep facial expression features from image and optical flow sequences using 3D CNN', The Visual Computer, vol. 34, no. 10, pp. 1461-1475.
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© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. Facial expression is highly correlated with the facial motion. According to whether the temporal information of facial motion is used or not, the facial expression features can be classified as static and dynamic features. The former, which mainly includes the geometric features and appearance features, can be extracted by convolution or other learning filters; the latter, which are aimed to model the dynamic properties of facial motion, can be calculated through optical flow or other methods, respectively. When 3D convolutional neural networks (CNNs) are introduced, the extraction of two different types of features mentioned above becomes easy. In this paper, one 3D CNN architecture is presented to learn the static and dynamic features from facial image sequences and extract high-level dynamic features from optical flow sequences. Two types of dense optical flow, which contain the tracking information of facial muscle movement, are calculated according to different image pair construction methods. One is the common optical flow, and the other is an enhanced optical flow which is called accumulative optical flow. Four components of each type of optical flow are used in experiments. Three databases, two acted databases and one nearly realistic database, are selected to conduct the experiments. The experiments on the two acted databases achieve state-of-the-art accuracy, and indicate that the vertical component of optical flow has an advantage over other components in recognizing facial expression. The experimental results on the three selected databases show that more discriminative features can be learned from image sequences than from optical flow or accumulative optical flow sequences, and the accumulative optical flow contains more motion information than optical flow if the frame distance of the image pairs used to calculate them is not too large.
Zhao, N, Yang, X, Ren, A, Zhang, Z, Zhao, W, Hu, F, Ur Rehman, M, Abbas, H & Abolhasan, M 2018, 'Antenna and Propagation Considerations for Amateur UAV Monitoring', IEEE Access, vol. 6, pp. 28001-28007.
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© 2013 IEEE. The broad application spectrum of unmanned aerial vehicles is making them one of the most promising technologies of Internet of Things era. Proactive prevention for public safety threats is one of the key areas with vast potential of surveillance and monitoring drones. Antennas play a vital role in such applications to establish reliable communication in these scenarios. This paper considers line-of-sight and non-line-of-sight threat scenarios with the perspective of antennas and electromagnetic wave propagation.
Zheng, D, Zhang, H, Zhang, JA & Su, SW 2018, 'Stability Analysis for Switched Systems with Sequence-based Average Dwell Time', International Journal of Control, pp. 1-9.
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This note investigates the stability of both linear and nonlinear switchedsystems with average dwell time. Two new analysis methods are proposed.Different from existing approaches, the proposed methods take into account thesequence in which the subsystems are switched. Depending on the predecessor orsuccessor subsystems to be considered, sequence-based average preceding dwelltime (SBAPDT) and sequence-based average subsequence dwell time (SBASDT)approaches are proposed and discussed for both continuous and discrete timesystems. These proposed methods, when considering the switch sequence, have thepotential to further reduce the conservativeness of the existing approaches. Acomparative numerical example is also given to demonstrate the advantages ofthe proposed approaches.
Zheng, D, Zhang, H, Zhang, JA & Wang, G 2018, 'Consensus of multi-agent systems with faults and mismatches under switched topologies using a delta operator method', Neurocomputing, vol. 315, pp. 198-209.
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© 2018 Elsevier B.V. This paper studies the consensus of multi-agent systems with faults and mismatches under switched topologies using a delta operator method. Since faults and mismatches can result in failure of the consensus even for a fixed topology with a spanning tree, how to reach a consensus is a complicated and challenging problem under such circumstances especially when part topologies have no spanning tree. Although some works studied the influence of faults and mismatches on the consensus, there is little work on reaching a consensus for the multi-agent systems with faults and mismatches. In this paper, we introduce the delta operator to unify the consensus analysis for continuous, discrete, or sampled systems under one framework. We develop the theories on the delta operator systems first and then apply theories of the delta operator systems to the consensus problems. By converting the consensus problems into stability problems, we investigate and prove consensus and the associated conditions for systems 1) without any fault, 2) with a known fault, and 3) with unknown faults, under switching topologies with matching or mismatching coefficients. Numerical examples are provided and validate the effectiveness of the theoretical results.
Zhong, Y, Dutkiewicz, E, Yang, Y, Zhu, X, Zhou, Z & Jiang, T 2018, 'Internet of Mission-Critical Things: Human and Animal Classification—A Device-Free Sensing Approach', IEEE Internet of Things Journal, vol. 5, no. 5, pp. 3369-3377.
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© 2014 IEEE. The well-known Internet of Things (IoT) is recently being considered for critical missions, such as search and rescue, surveillance, and border patrol. One of the most critical issues that these applications are currently facing is how to correctly distinguish between human and animal targets in a cost-effective way. In this paper, we present a relatively low-cost, but robust approach that uses a combination of device-free sensing (DFS) and machine-learning technologies to tackle this issue. In order to validate the feasibility of the presented approach, a variety of data is collected in a cornfield using impulse-radio ultra-wideband (IR-UWB) transceivers. These data are then used to investigate the influence of different statistical properties of the radio-frequency (RF) signal on the accuracy of human/animal target classification. Based on the probability density function of different statistical properties, two distinguishing features for target classification are found, namely, standard deviation and root mean spread delay spread. Using them, the impact on the classification accuracy due to different classifiers, number of training samples, and different values of signal-To-noise ratio is extensively verified. Even with the worst case, the classification accuracy of the system is still better than 91% in terms of distinguishing between human and animal targets (including goats and dogs), which indicates that the presented approach has a great potential to be deployed in the near future.
Zhong, Y, Yang, Y, Zhu, X, Huang, Y, Dutkiewicz, E, Zhou, Z & Jiang, T 2018, 'Impact of Seasonal Variations on Foliage Penetration Experiment: A WSN-Based Device-Free Sensing Approach', IEEE Transactions on Geoscience and Remote Sensing, vol. 56, no. 9, pp. 5035-5045.
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© 2018 IEEE. Foliage penetration (FOPEN) has been found to be a critical mission for a variety of applications, ranging from surveillance to military. Recently, an emerging technology, namely wireless sensor network (WSN)-based device-free sensing (DFS), has been introduced to the domain of FOPEN. This technology only utilizes radio-frequency signals for target detection and classification; thus, no additional hardware is required, just a wireless transceiver. Although the feasibility of using this technology for human detection indoors has been explored to some extent, it is questionable if the same technology can be transferred to outdoors. As far as FOPEN is concerned, the impact of seasonal variations on detection accuracy can be severe. To address this concern, in this paper, an experiment is conducted in four seasons, and how to ensure reasonable detection accuracy with seasonal variations is intensively investigated. To fully evaluate the potential of using the WSN-based DFS for FOPEN, an impulse-radio ultrawideband technology-based prototype is used to collect data samples in different seasons. Unlike the conventional approach based on a combination of statistical properties of received-signal strength and a support vector machine, this approach adopts two special measures for performance enhancement. One measure is to use a higher order cumulant (HOC) algorithm for feature extraction, so that the impact on detection accuracy due to unwanted clutters can be minimized. The other one is to determine the optimal parameters of the classifier by means of a flower pollination algorithm. Consequently, the adverse effects on detection accuracy due to variations of weather conditions in four seasons can be accommodated. According to the experimental result, it is shown that the average classification accuracy of the presented approach can be improved by at least 20% under all seasons with an ensured robustness.
Zhou, Y, Zheng, K, Ni, W & Liu, RP 2018, 'Elastic Switch Migration for Control Plane Load Balancing in SDN', IEEE Access, vol. 6, pp. 3909-3919.
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© 2013 IEEE. Software-defined network (SDN) provides a solution for the scalable network framework with decoupled control and data plane. Migrating switches can balance the resource utilization of controllers and improve network performance. Switch migration problem has to date been formulated as a resource utilization maximization problem to address the scalability of the control plane. However, this problem is NP-hard with high-computational complexities and without addressing the security challenges of the control plane. In this paper, we propose a switch migration method, which interprets switch migration as a signature matching problem and is formulated as a 3-D earth mover's distance model to protect strategically important controllers in the network. Considering the scalability, we further propose a heuristic method which is time-efficient and suitable to large-scale networks. Simulation results show that our proposed methods can disguise strategically important controllers by diminishing the difference of traffic load between controllers. Moreover, our proposed methods can significantly relieve the traffic pressure of controllers and prevent saturation attacks.
Zhu, H & Abbosh, AM 2018, 'A Compact Tunable Directional Coupler with Continuously Tuned Differential Phase', IEEE Microwave and Wireless Components Letters, vol. 28, no. 1, pp. 19-21.
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© 2001-2012 IEEE. A tunable directional coupler with outputs that have continuously tuned phase difference and constant magnitude is presented. The initial design is based on a 3-dB branch-line coupler with two arms having variable electrical lengths. To realize the variable-length lines, a novel concept of tunable phase shifting unit, which includes a pair of inductor-varactor loaded coupled lines, is proposed. By controlling the shifting phase of the two arms, the differential phase (i.e., the phase difference between the two output ports) can be tuned continuously. Explicit relation between the objective differential phase of the device and the required shifting phase of those units is analyzed and explained. To validate the design, a prototype is built, simulated, and tested. The experimental and predicted results agree well and show that the device can realize arbitrary and continuously tunable differential phase from 45° to 135°. The overall size of the design is only 0.18 λ{g} \times 0.24 λ{g} , which is extremely compact compared with using a cascaded coupler-phase shifters and is thus suitable for miniaturized wireless systems.
Zhu, H, Abbosh, AM & Guo, L 2018, 'Planar In-Phase Filtering Power Divider With Tunable Power Division and Controllable Band for Wireless Communication Systems', IEEE Transactions on Components, Packaging and Manufacturing Technology, vol. 8, no. 8, pp. 1458-1468.
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© 2011-2012 IEEE. A wideband in-phase power divider with tunable power division ratio (PDR) and filtering response is presented. The proposed design is quite compact and consists of a three-line coupled structure and loaded with a pair of varactor-loaded short-ended stubs at two output terminations. A variable power division is realized by tuning the coupling factors between the centerline and sidelines of the three-line coupled structure using a pair of varactors. A varactor at the center of the loaded short-ended stub and another one connecting the end of the stub to the ground is used to control the center frequency and band of operation. A prototype is modeled using the microstrip technique and then simulated and tested. The experimental result indicates a tunability of PDR from 0.5:1 to 2:1 across wideband range of 60% and a controllable band from 35% to 63.2%, with 13% center frequency tunability, sharp passband cutoff selectivity, as well as harmonic suppression to more than 6 GHz (4 times the center frequency). Moreover, the overall loss is around 1-1.2 dB; the isolation is more than 14 dB, whereas the differential phase is less than 7° in all the investigated cases.
Zhu, H, Yang, Y, Zhu, X, Sun, Y & Wong, S-W 2018, 'Miniaturized Resonator and Bandpass Filter for Silicon-Based Monolithic Microwave and Millimeter-Wave Integrated Circuits', IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 65, no. 12, pp. 4062-4071.
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© 2018 IEEE. This paper introduces a unique approach for the implementation of a miniaturized on-chip resonator and its application for the first-order bandpass filter (BPF) design. This approach utilizes a combination of a broadside-coupling technique and a split-ring structure. To fully understand the principle behind it, simplified LC equivalent-circuit models are provided. By analyzing these models, guidelines for implementation of an ultra-compact resonator and a BPF are given. To further demonstrate the feasibility of using this approach in practice, both the implemented resonator and the filter are fabricated in a standard 0.13-μm (Bi)-CMOS technology. The measured results show that the resonator can generate a resonance at 66.75 GHz, while the BPF has a center frequency at 40 GHz and an insertion loss of 1.7 dB. The chip size of both the resonator and the BPF, excluding the pads, is only 0.012mm2 (0.08 × 0.144 mm2).
Zhu, H, Zhu, X, Yang, Y & Xue, Q 2018, 'Design of Wideband Third-Order Bandpass Filters Using Broadside-Coupled Resonators in 0.13-$\mu$ m (Bi)-CMOS Technology', IEEE Transactions on Microwave Theory and Techniques, vol. 66, no. 12, pp. 5593-5604.
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© 2018 IEEE. In this paper, two third-order bandpass filters (BPFs) designed for millimeter-wave applications are presented. Unlike previously published ones, the proposed designs use a 'cell-based' approach, which utilizes identical broadside-coupled resonators (BCRs) with series and shunt capacitors. The capacitors are mainly used as J -inverters to achieve the desired frequency responses. To fully understand the operational mechanism of the presented approach, both the BCR and BPFs are analyzed using the simplified LC-equivalent circuit models. To prove the concept, both BPFs are implemented in a standard 0.13- μm silicon-germanium bipolar complementary metal-oxide-semiconductor technology. According to the on-wafer measurement results, the BPFs exhibit the excellent performance including flat in-band responses with relatively large harmonic suppression. The first design has a 1-dB bandwidth from 23.9 to 39.7 GHz with an insertion loss of 3.9 dB at the center frequency of 31 GHz. The stopband attenuation is better than 45 dB at 58 GHz. The 1-dB bandwidth of the second design covers from 26.7 to 44.3 GHz with an insertion loss of 3.1 dB at the center frequency of 35 GHz, and stopband attenuation up to 35 dB is achieved at 59 GHz. Both designs occupy an identical area of 0.073 mm 2 (0.248×0.294 mm 2 ), excluding the G-S-G testing pads.
Zhu, J, Liao, S, Yang, Y, Li, S & Xue, Q 2018, '60 GHz Dual-Circularly Polarized Planar Aperture Antenna and Array', IEEE Transactions on Antennas and Propagation, vol. 66, no. 2, pp. 1014-1019.
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© 1963-2012 IEEE. This communication presents new designs of dual-circularly polarized (CP) planar aperture antenna and array for 60 GHz applications. First, a four-port planar aperture antenna with its feeding network is developed that exhibits wide impedance bandwidth, dual-CP radiation as well as high gain. Then, based on the proposed antenna, a new scheme of building a dual-CP array is proposed. With this new scheme that combines the power splitting network and series feeding method, four sequentially fed antenna elements are successfully combined to form a CP radiation array. The experimental results show that the -10 dB impedance bandwidths of the antenna and the array are more than 18.2% (55-66 GHz). While the 3 dB axial ratio bandwidths are from 54.2 to 64.3 GHz (17.2%) for the antenna and from 54.8 to 65 GHz (17%) for the array. The maximum gains achieved are 13.7 and 17.85 dBic for the antenna and array, respectively.
Zhu, M, He, B & Wu, Q 2018, 'Single Image Dehazing Based on Dark Channel Prior and Energy Minimization', IEEE Signal Processing Letters, vol. 25, no. 2, pp. 174-178.
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© 2017 IEEE. Hazy images have limited visibility and low contrast. The degradation is expressed by transmission map, which is one of the most important estimates of single image dehazing. Transmission map estimation is an underconstraint problem, and lots of priors have been proposed. Among them, the dark channel prior is widely recognized. However, traditional methods have not fully exploited its power due to improper assumptions or operations, which cause unwanted artifacts. The postrefinement algorithms employed to remove these artifacts in turn undermine the merits of the prior. In this letter, a novel method for estimating transmission map by energy minimization is proposed to solve this problem. The energy function combines the dark channel prior with piecewise smoothness. The method is compared to the state-of-the-art methods and shows outstanding performance.
Zou, S, Tang, Y, Ni, W, Liu, RP & Wang, L 2018, 'Resource multi-objective mapping algorithm based on virtualized network functions: RMMA', Applied Soft Computing, vol. 66, pp. 220-231.
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Zuo, Y, Wu, Q, An, P & Shang, X 2018, 'Integrated cosparse analysis model with explicit edge inconsistency measurement for guided depth map upsampling', Journal of Electronic Imaging, vol. 27, no. 04, pp. 1-1.
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© 2018 SPIE and IS & T. A low-resolution depth map can be upsampled through the guidance from the registered high-resolution color image. This type of method is so-called guided depth map upsampling. Among the existing methods based on Markov random field (MRF), either data-driven or model-based prior is adopted to construct the regularization term. The data-driven prior can implicitly reveal the relation between color-depth image pair by training on external data. The model-based prior provides the anisotropic smoothness constraint guided by high-resolution color image. These types of priors can complement each other to solve the ambiguity in guided depth map upsampling. An MRF-based approach is proposed that takes both of them into account to regularize the depth map. Based on analysis sparse coding, the data-driven prior is defined by joint cosparsity on the vectors transformed from color-depth patches using the pair of learned operators. It is based on the assumption that the cosupports of such bimodal image structures computed by the operators are aligned. The edge inconsistency measurement is explicitly calculated, which is embedded into the model-based prior. It can significantly mitigate texture-copying artifacts. The experimental results on Middlebury datasets demonstrate the validity of the proposed method that outperforms seven state-of-the-art approaches.
Zuo, Y, Wu, Q, Zhang, J & An, P 2018, 'Explicit Edge Inconsistency Evaluation Model for Color-Guided Depth Map Enhancement', IEEE Transactions on Circuits and Systems for Video Technology, vol. 28, no. 2, pp. 439-453.
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© 2016 IEEE. Color-guided depth enhancement is used to refine depth maps according to the assumption that the depth edges and the color edges at the corresponding locations are consistent. In methods on such low-level vision tasks, the Markov random field (MRF), including its variants, is one of the major approaches that have dominated this area for several years. However, the assumption above is not always true. To tackle the problem, the state-of-the-art solutions are to adjust the weighting coefficient inside the smoothness term of the MRF model. These methods lack an explicit evaluation model to quantitatively measure the inconsistency between the depth edge map and the color edge map, so they cannot adaptively control the efforts of the guidance from the color image for depth enhancement, leading to various defects such as texture-copy artifacts and blurring depth edges. In this paper, we propose a quantitative measurement on such inconsistency and explicitly embed it into the smoothness term. The proposed method demonstrates promising experimental results compared with the benchmark and state-of-the-art methods on the Middlebury ToF-Mark, and NYU data sets.
Zuo, Y, Wu, Q, Zhang, J & An, P 2018, 'Minimum Spanning Forest With Embedded Edge Inconsistency Measurement Model for Guided Depth Map Enhancement', IEEE Transactions on Image Processing, vol. 27, no. 8, pp. 4145-4159.
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© 1992-2012 IEEE. Guided depth map enhancement based on Markov random field (MRF) normally assumes edge consistency between the color image and the corresponding depth map. Under this assumption, the low-quality depth edges can be refined according to the guidance from the high-quality color image. However, such consistency is not always true, which leads to texture-copying artifacts and blurring depth edges. In addition, the previous MRF-based models always calculate the guidance affinities in the regularization term via a non-structural scheme, which ignores the local structure on the depth map. In this paper, a novel MRF-based method is proposed. It computes these affinities via the distance between pixels in a space consisting of the minimum spanning trees (forest) to better preserve depth edges. Furthermore, inside each minimum spanning tree, the weights of edges are computed based on the explicit edge inconsistency measurement model, which significantly mitigates texture-copying artifacts. To further tolerate the effects caused by noise and better preserve depth edges, a bandwidth adaption scheme is proposed. Our method is evaluated for depth map super-resolution and depth map completion problems on synthetic and real data sets, including Middlebury, ToF-Mark, and NYU. A comprehensive comparison against 16 state-of-the-art methods is carried out. Both qualitative and quantitative evaluations present the improved performances.
Abeywickrama, HV, Jayawickrama, BA, He, Y & Dutkiewicz, E 1970, 'Empirical Power Consumption Model for UAVs', 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), IEEE, Chicago, IL, USA, USA, pp. 1-5.
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© 2018 IEEE. Unmanned Aerial Vehicles (UAV) are gaining popularity in a range of areas and are already being used for a wide variety of purposes. While UAVs have many desirable features, limited battery lifetime is identified as a key restriction in UAV applications. Typical UAVs being electric devices, powered by on-board batteries, this constrain has limited their capabilities to a considerable extent. Thus planning UAV missions in an energy efficient manner is of utmost importance. To achieve this, for prediction of power consumption, it is necessary to have a reliable power consumption model. In this paper, we present a consistent and complete power consumption model for UAVs based on empirical studies of battery usage for various UAV activities. The power consumption model presented in this paper can be readily used for energy efficient UAV mission planning.
Abeywickrama, HV, Jayawickrama, BA, He, Y & Dutkiewicz, E 1970, 'Potential Field Based Inter-UAV Collision Avoidance Using Virtual Target Relocation', 2018 IEEE 87th Vehicular Technology Conference (VTC Spring), 2018 IEEE 87th Vehicular Technology Conference (VTC Spring), IEEE, Porto, Portugal, pp. 1-5.
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© 2018 IEEE. Unmanned Aerial Vehicles (UAV) are becoming popular in a range of areas. This has given rise to the concept of UAV swarms, where multiple UAVs act together to achieve a common task. With multiple UAVs flying in close proximity to each other, sharing the same airspace, the risk of inter-UAV collisions increases. It's important to avoid these collisions while having minimal impact on the UAV system. We propose a novel Potential Field Method (PFM) based algorithm for inter-UAV collision avoidance which considerably reduces the total time taken by the UAV system to achieve its goal. We control the collision avoidance actions of the UAVs by virtually relocating their targets. The positions of the virtual targets are calculated to minimize the collision probability, based on a probability function we introduced. The proposed algorithm reduces the total system time approximately by 20\% as opposed to the traditional PFM.
Ajayan, AR, Al-Doghman, F & Chaczko, Z 1970, 'Visualizing Multimodal Big Data Anomaly Patterns in Higher-Order Feature Spaces', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE, Sydney, NSW, Australia, pp. 1-9.
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The world today, as we know it, is profuse with information about humans and objects. Datasets generated by cyber-physical systems are orders of magnitude larger than their current information processing capabilities. Tapping into these big data flows to uncover much deeper perceptions into the functioning, operational logic and smartness levels attainable has been investigated for quite a while. Knowledge Discovery & Representation capabilities across mutiple modalities holds much scope in this direction, with regards to their information holding potential. This paper investigates the applicability of an arithmetic tool Tensor Decompositions and Factorizations in this scenario. Higher order datasets are decomposed for Anomaly Pattern capture which encases intelligence along multiple modes of data flow. Preliminary investigations based on data derived from Smart Grid Smart City Project are compliant with our hypothesis. The results proved that Abnormal patterns detected in decomposed Tensor factors encompass deep information energy content from Big Data as efficiently as other Pattern Extraction and Knowledge Discovery frameworks, while salvaging time and resources.
Al-Doghman, F, Chaczko, Z & Brookes, W 1970, 'Adaptive Consensus-based Aggregation for Edge Computing', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE, Sydney, Australia.
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The swift expansion in employing IoT and the tendency to apply its application have encompassed a wide range of fields in our life. The heterogeneity and the massive amount of data produced from IoT require adaptive collection and transmission processes that function closed to front-end to mitigate these issues. In this paper, We introduced a method
of aggregating IoT data in a consensus way using Bayesian analysis and Markov Chain techniques. The aim is to enhance the quality of data traveling within IoT framework.
Amirgholipour, S, He, X, Jia, W, Wang, D & Zeibots, M 1970, 'A-CCNN: Adaptive CCNN for Density Estimation and Crowd Counting', 2018 25th IEEE International Conference on Image Processing (ICIP), 2018 25th IEEE International Conference on Image Processing (ICIP), IEEE, Athens, Greece, pp. 948-952.
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© 2018 IEEE. Crowd counting, for estimating the number of people in a crowd using vision-based computer techniques, has attracted much interest in the research community. Although many attempts have been reported, real-world problems, such as huge variation in subjects' sizes in images and serious occlusion among people, make it still a challenging problem. In this paper, we propose an Adaptive Counting Convolutional Neural Network (A-CCNN) and consider the scale variation of objects in a frame adaptively so as to improve the accuracy of counting. Our method takes advantages of contextual information to provide more accurate and adaptive density maps and crowd counting in a scene. Extensively experimental evaluation is conducted using different benchmark datasets for object-counting and shows that the proposed approach is effective and outperforms state-of-the-art approaches.
Anwar, MJ, Gill, AQ & Beydoun, G 1970, 'A review of information privacy laws and standards for secure digital ecosystems', ACIS 2018 - 29th Australasian Conference on Information Systems, Australasian Conference on Information Systems, Sydney, Australia.
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© 2018 authors. Information privacy is mainly concerned with the protection of personally identifiable information. Information privacy is an arduous task, in particular, in the context of complex adaptive and multi-party heterogeneous digital ecosystems. There is a need to identify and understand the relevant privacy laws and standards for designing the secure digital ecosystems. This paper presents the results of our information privacy research in digital ecosystems through the lens of local and international privacy regulations and standards. A qualitative research method was applied to review a set of identified privacy laws across the four layers of digital ecosystem. The evaluation criteria has been applied to evaluate the applicability and coverage of the selected seven information privacy laws to people, process, information and technology layers of the digital ecosystems. The research results indicate that information privacy is a critical phenomenon; however, it is not adequately addressed in the context of end-to-end digital ecosystems. It is recommended that a multi-layered privacy by design approach is required by reviewing and mapping information privacy laws and standards to design the secure digital ecosystems.
Bah, AO, Ziolkowski, RW, Pei-Yuan Qin & Guo, YJ 1970, 'Design and Analysis of a Wide Angle Impedance Matching Metasurface for Wideband Antenna Arrays', 12th European Conference on Antennas and Propagation (EuCAP 2018), 12th European Conference on Antennas and Propagation (EuCAP 2018), Institution of Engineering and Technology, London.
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© Institution of Engineering and Technology.All Rights Reserved. A wide bandwidth, low profile, double sided, wide angle impedance matching metasurface is reported. It alleviates the well-known problem of impedance mismatch caused by mutual coupling when an array is in its scan mode. Each unit cell of the metasurface contains two multi-resonant, tightly-coupled unequal arm Jerusalem cross elements on the top and bottom sides of a thin substrate. Each element consists of two orthogonal capacitively loaded strips. The wide bandwidth of the metasurface is achieved by tightly coupling these multi-resonant elements. The metasurface is capable of facilitating wide angle scanning over a 6:1 impedance bandwidth without the need for bulky dielectrics or multi-layered structures.
Basnet, S, Jayawickrama, BA, He, Y & Dutkiewicz, E 1970, 'Fairness Aware Resource Allocation for Average Capacity Maximisation in General Authorized Access User', 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), IEEE, Chicago, IL, USA, USA, pp. 1-5.
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© 2018 IEEE. Spectrum Access System (SAS) is a three-tier spectrum sharing framework proposed for 3.5 GHz by Federal Communication Commission (FCC) in the United States. General Authorized Access (GAA) users in SAS do not have an assigned channel and can opportunistically access the Priority Access Licensee (PAL) channel satisfying the interference constraint proposed by FCC. Coexistence among GAA users in SAS is a key problem to be solved to enhance the system capacity to meet the increasing traffic demand. In this work, we propose a method for fair and efficient spectrum utilisation for GAA users. To achieve the fairness among GAA users equal interference budget allocation scheme is proposed for each set of GAA users that can hear each other. Our proposed method decide the optimal channel switching schedule that maximises the average capacity of GAA users while satisfying the interference constraint at PAL protection area. This work jointly considers the fairness between GAA users and the average capacity maximisation of GAA network. Simulation result justifies the performance of our proposed method for average capacity maximisation of GAA users and fairness between GAA users by comparing with existing works.
Basnet, S, Jayawickrama, BA, He, Y & Dutkiewicz, E 1970, 'Transmit Power Allocation for General Authorized Access in Spectrum Access System Using Carrier Sensing Range', 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), IEEE, Chicago, IL, USA, USA, pp. 1-5.
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© 2018 IEEE. The optimal use of spectrum is a key focus for all regulatory bodies. Federal Communications Commission has introduced Spectrum Access System (SAS) to maximise the spectrum utilisation in the US 3.5 GHz band. SAS is a three-tier spectrum sharing framework where Citizen Broadband Radio Service (CBRS) devices can access the channel when it is not used by Incumbent Access users. CBRS consists of Priority Access Licensee (PAL) and General Authorized Access (GAA). In this paper, we consider the problem of optimum transmit power allocation for GAA users using a carrier sensing range i.e. maximum distance a user can be sensed while guaranteeing the interference to PAL from GAA users is below the threshold. We use carrier sensing range to find the sets of GAA users that cannot transmit at the same time and adjust the interference budget of transmitting GAA users. We present an algorithm for transmit power allocation for GAA users in the SAS. The proposed algorithm uses the transmission characteristics and location information provided by Citizen Broadband Radio Service Devices to SAS to maximise the peak capacity of GAA users ensuring the interference constraint to PAL. Simulation results show that the proposed algorithm significantly increases the peak capacity of GAA users by considering the carrier sensing range and adjusted interference budget.
Bautista, MG, Hora, J & Dutkiewicz, E 1970, 'Design Methodology of a Miniaturized Millimetre Wave Integrated Passive Resonator Using (Bi)-CMOS Technology', 2018 18TH INTERNATIONAL SYMPOSIUM ON COMMUNICATIONS AND INFORMATION TECHNOLOGIES (ISCIT), 18th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Bangkok, THAILAND, pp. 147-151.
Bautista, MG, Zhang, XP, Zhu, X & Dutkiewicz, E 1970, 'Design of On-Chip Edge-Coupled Resonator and Its Application for Bandpass Filter in CMOS Technology', 2018 18TH INTERNATIONAL SYMPOSIUM ON COMMUNICATIONS AND INFORMATION TECHNOLOGIES (ISCIT), 18th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Bangkok, THAILAND, pp. 137-140.
Bautista, MG, Zhang, XP, Zhu, X & Dutkiewicz, E 1970, 'Design of On-Chip Edge-Coupled Resonator and Its Application for Bandpass Filter in CMOS Technology', 2018 18th International Symposium on Communications and Information Technologies (ISCIT), 2018 18th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Bangkok, Thailand, pp. 137-140.
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© 2018 IEEE. In this work, the design of a compact on-chip edge-coupled resonator is presented. To understand the insight of the presented resonator, a simplified LC-equivalent circuit model is provided, and electromagnetic simulation is utilized for performance optimization. To demonstrate the potential of the presented resonator, a bandpass filter design example is also given. By taking advantage of using metal-insulator-metal capacitors, a compact filter can be designed. For proving of concept, both the presented resonator and filter are implemented and fabricated using standard CMOS technology. A good agreement between simulation and measurement has been achieved. The measured results show that the filter has a resonance at 35.4 GHz with an insertion loss of 1.7 dB and greater than-10 dB of return loss. The miniaturized chip area of both the resonator and the BPF, excluding the pads, is only 0.039 mm 2 (0.15 × 0.26 mm 2 ).
Braun, R, Miller, G, Chaczko, Z & Brookes, W 1970, 'First experiences of Studios in the new Data Engineering program', 2018 17th International Conference on Information Technology Based Higher Education and Training (ITHET), 2018 17th International Conference on Information Technology Based Higher Education and Training (ITHET), IEEE, Olhao, Portugal, pp. 1-5.
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© 2018 IEEE. This paper describes the Studio experiences created for Data and Electronic Engineering students at the University of Technology Sydney. It describes the purpose of the Studios, and their structure. It completes with a retrospective of what worked, and what did not work, and suggests future changes.
Cao, Y & Veitch, D 1970, 'Network Timing, Weathering the 2016 Leap Second', IEEE INFOCOM 2018 - IEEE Conference on Computer Communications, IEEE INFOCOM 2018 - IEEE Conference on Computer Communications, IEEE, Honolulu, HI, USA, pp. 1826-1834.
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© 2018 IEEE. We collect high resolution timing packet data from 459 public Stratum-1 NTP servers during the leap second event of Dec. 2016, including all those participating in the NTP Pool Project, using a testbed with GPS and atomic clock synchronized DAG cards. We report in detail on a wide variety of anomalous behaviors found both at the NTP protocol level, and in the detailed timestamp performance of the server clocks themselves, which can last days or even weeks after the event. Overall, only 37.3% of servers had Adequate performance overall.
Casareo, K & Chaczko, Z 1970, 'Beacon-Based Localization Middleware for Tracking in Medical and Healthcare Environments', 2018 12th International Symposium on Medical Information and Communication Technology (ISMICT), 2018 12th International Symposium on Medical Information and Communication Technology (ISMICT), IEEE, Sydney, NSW, Australia, pp. 1-6.
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© 2018 IEEE. This research paper proposes a Middleware model for a Localization System that may be applied in Healthcare environments such as Hospitals or Nursing Homes to track staff, patients, visitors and equipment. It investigates literature regarding indoor localization methods and limitations to determine a suitable algorithm that may be implemented in an infrastructure oriented software. The methodology used to build and test the software is explained. It then illustrates the concept of the Localization Middleware and how it might be used when deployed indoor premises, inside such rooms as a hospital wards, In terms of the functional responsibilities, it is expected to offer an effective implementation of the distance measurement algorithm for Received Signal Strength and the Linear Least-Squares localization algorithm. The simulations of the localization algorithm with the given simulation results are looking promising. However, the real-time tests demonstrated that the range measurement was insufficiently precise to be reliable. Given a more accurate and reliable distance measurement, a more precise localization result could be attained.
Chaczko, Z, Gordon, LC & Bożejko, W 1970, 'The Metamodel of Heritage Preservation for Medical Big Data', Computer Aided Systems Theory – EUROCAST 2017 (LNCS), International Conference on Computer Aided Systems Theory, Springer International Publishing, Las Palmas de Gran Canaria, Spain, pp. 366-371.
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At present the real challenge of Digital Data Preservation concerns methods of keeping all important attributes of the data and preserving their originality. The key is to keep the living part of the data. It is the essence of the Heritage concept. The Heritage is about the concrete data the concept gives the interconnection to other aspects of the reality. Nowadays the physical value and the aspects of items complete the relevance of information. But the question is what is heritage and which parameters defining the artifact or the information as a heritage? The context and the interpretation of data is the answer. The heritage term is defining as the crucial and central part of the presented research. Big data analytics in healthcare is evolving into a promising field for providing insight from very large data sets and improving outcomes while reducing costs.
Chaczko, Z, Kale, A, Santana-Rodriguez, JJ & Suarez-Araujo, CP 1970, 'Towards an IOT Based System for Detection and Monitoring of Microplastics in Aquatic Environments', 2018 IEEE 22nd International Conference on Intelligent Engineering Systems (INES), 2018 IEEE 22nd International Conference on Intelligent Engineering Systems (INES), IEEE, Las Palmas de Gran Canaria, Spain, pp. 000057-000062.
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© 2018 IEEE. Monitoring presence of micro-plastics in the ocean and fresh waters is an important research topic due to a need to preserve marine ecosystem. Microplastics represent threats to living organisms, producing harmful effects, ultimately also having an impact on humans through the food-chain. Use of laboratory-based and in situ techniques do help in investigating density and scale of this kind of pollutants. The in-situ sensing techniques are gaining popularity due to automation and continuous availability. These techniques though need an accurate hardware and efficient computing model to achieve desired success. Here, we propose an IoT based system called 'SmartIC' using specialized sensors and intelligent computing tools, specifically designed for in-situ monitoring of microplastics in natural aquatic environments. This paper is focused on system architecture, monitoring process and outline of experimental work. The initial research provides very promising results. A further course of the investigation with validation will be conducted in future to establish the proposed system completely.
Chaczko, Z, Klempous, R, Nikodem, J & Rozenblit, J 1970, '24/7 Model of Collaborative Engineering', 2018 IEEE 22nd International Conference on Intelligent Engineering Systems (INES), 2018 IEEE 22nd International Conference on Intelligent Engineering Systems (INES), IEEE, Las Palmas de Gran Canaria, Spain, pp. 000013-000014.
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© 2018 IEEE. This paper presents a short overview of pioneering work on the 24/7 model of collaborative engineering and its practical applications in software development domain. The primary goal of the approach was to enable students, engineers and researchers to practice collaboration in virtual space. The secondary goal was to learn how to cooperatively manage and execute engineering projects more efficiently and on-time. The model relies on collaborative and consensus based agreements among geographically distributed institutions. These institutions agree to participate in cooperative and continuous (24/7) mode of operation where participating teams execute interdisciplinary tasks across different geographic, temporal and cultural zones. The interest in various collaborative models is steadily increasing. The idea has been adopted by many sectors of the industry, research and education, allowing for smart logistics and transportation, interdisciplinary product development, manufacturing design, global monitoring, international enterprise collaboration and many other applications. This paper explains the key concepts, the methodology, projects undertaken and tools developed during many years of collaboration between several prestigious educational institutions.
Chaczko, Z, Slehar, S & Shnoudi, T 1970, 'Game-Theory Based Cognitive Radio Policies for Jamming and Anti-Jamming in the IoT', 2018 12th International Symposium on Medical Information and Communication Technology (ISMICT), 2018 12th International Symposium on Medical Information and Communication Technology (ISMICT), IEEE, Sydney, NSW, Australia.
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© 2018 IEEE. The Cognitive Radio can be considered as a mandatory part of the Internet of Things applications. It helps to solve the sacristy issues in the frequency bands of the wireless network component of the technology. However, the security problem is the primary challenge that needs to be carefully mitigated. Specifically, defending the Cognitive Radio mechanism against the jamming attacks. The aim this research paper is to investigate and provide a reliable and adaptive Cognitive Radio protection methods against the jamming attacks. Thus, improving the performance of the wireless network of IoT technology, enhancing the bandwidth and solving the issue of the sacristy of the frequency bands. The mentioned objectives will be accomplished by the aid of the game theory which is modelled as an anti-jamming game and by adapting the multi-arm bandit (MAB) policies. However, to solve the sacristy issue in the frequency band spectrum of the cognitive radio, some MAB policies were adapted such as Upper Confidence Bound (UCB), Thompson Sampling and Kullback-Leibler Upper Confidence Bound (KL-UCB). The results show some improvements and enhancements to the sacristy problem in the frequency band spectrum. To conclude, the Thompson Sampling MAB policy was the best to be adapted for solving the problem, as it resulted with lowest regrets and highest rewards compared to the other MAB policies.
Chaczko, Z, Wazirali, R, Gordon, LC & Bożejko, W 1970, 'Steganographic Data Heritage Preservation Using Sharing Images App', Springer International Publishing, pp. 150-156.
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Chemalamarri, VD, Braun, R, Lipman, J & Abolhasan, M 1970, 'A Multi-agent Controller to enable Cognition in Software Defined Networks', 2018 28th International Telecommunication Networks and Applications Conference (ITNAC), 2018 28th International Telecommunication Networks and Applications Conference (ITNAC), IEEE, Sydney, Australia, pp. 52-56.
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© 2018 IEEE. Current SDN controllers are not cognitive. We propose a new architecture for an SDN controller to enable intelligence. The proposed new architecture is based on Multi-agent systems. As a prototype, we have built a MAS-SDN controller using the GOAL agent programming language. We highlight the motivation behind the new architecture, describe the architecture and provide some initial results.
Cheng, Q, Nguyen, DN, Dutkiewicz, E & Mueck, MD 1970, 'Protecting Operational Information of Incumbent and Secondary Users in FCC Spectrum Access System', 2018 IEEE International Conference on Communications (ICC), 2018 IEEE International Conference on Communications (ICC 2018), IEEE, Kansas City, MO, USA.
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© 2018 IEEE. Both Federal Communications Commission (FCC) and European Telecommunications Standards Institute (ETSI) support dynamic spectrum access (DSA) as an enabling technology for spectrum sharing. To effectively realize DSA in practice, users (from both defense and civil sectors) are required to share their (radio) operational information. That risks exposing their security, privacy, and business plan to unintended agents. In this paper, taking FCC's spectrum access system (SAS) as a study case, we propose a privacy-preserving scheme for DSA by leveraging encryption and obfuscation methods (PSEO). To implement PSEO, we propose an interference calculation scheme that allows users to calculate interference budget without revealing their operation information (e.g., antenna height, transmit power, location...), referred to as blind interference calculation method (BICM). BICM also reduces the computing overhead of PSEO, compared with FCC's SAS by moving interference budgeting tasks to local users and calculating it in an offline manner. Extensive detailed analysis and simulations show that our proposed PSEO is able to better protect all users' operational privacy, guaranteeing efficient spectrum utilization with less online overhead, compared with state of the art approaches.
Cui, P-F, Zhang, JA, Lu, W-J, Guo, YJ & Zhu, H-B 1970, 'Sparse Channel Modelling Using Multi-Measurement Vector Compressive Sensing', 2018 IEEE Global Communications Conference (GLOBECOM), GLOBECOM 2018 - 2018 IEEE Global Communications Conference, IEEE, Abu Dahbi, UAE.
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© 2018 IEEE. Channel sparsity is well exploited for channel estimation, but there is very limited work on sparse channel modelling, which studies and characterizes the statistical properties of sparse channel coefficients. In this paper, we study sparse channel modelling using real measured channel data in off-body signal propagation. We propose multi-measurement vector based compressive sensing algorithms for extracting sparse channel coefficients, study the statistical properties of these extracted coefficients, and develop an algorithm for generating simulated channels using the statistical sparse model. The proposed method can be directly applied to other channel measurements, and is very useful for channel simulation and developing advanced sparse channel estimation schemes.
Debabrata Karmokar, K & Jay Guo, Y 1970, 'Continuous Backward-to-Forward Beam-Scanning Conformal Leaky-Wave Antenna', 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP), 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP), IEEE, Auckland, New Zealand, pp. 72-73.
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© 2018 IEEE. A periodic substrate integrated waveguide (SIW) structure based conformal leaky-wave antenna (LWA) is presented. The LWA is capable of scanning its beam from near backfire, backward endfire, through the broadside to the forward direction. The-10-dB reflection coefficient bandwidth of the antenna is 7.428-10.47 GHz. The gain of the antenna is greater than 10 dBi throughout the beam scan range from-84° to +19°with a variation of source frequency from 7.3 to 10.3 GHz.
Diao, Y, Li, M, Sun, W, Leung, SW, Cai, Y, Zhu, F & Yang, Y 1970, 'Safety Consideration for Emerging Wireless Technologies-Evaluations of Temperature Rise in Eyes for RF Radiations up to 10 GHz', 2018 12th International Symposium on Medical Information and Communication Technology (ISMICT), 2018 12th International Symposium on Medical Information and Communication Technology (ISMICT), IEEE, Sydney, NSW, Australia.
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© 2018 IEEE. The study of temperature rise distribution in the human eye under plane electromagnetic wave exposure up to 10 GHz is presented in this paper. The effects of different frequencies and different blood perfusion rates of sclera to thermal calculations are investigated by finite difference method. The results reveal that the changes in the thermal parameter produce a maximum relative standard deviation of ~15% in the temperature rise in lens.
Ding, C, Sun, H, Guo, YJ & Ziolkowski, RW 1970, 'A general design and optimization method of tightly-coupled cross-dipoles for base station', IET Conference Publications, European Conference on Antennas and Propagation, London, UK.
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This paper investigates the working mechanism of dual-polarized tightly-coupled cross-dipoles that are widely used in cellular base station applications. The effects of couplings between sub-dipoles on the performance indexes of concern are observed. A theory of considering this type of cross-dipole as an array is proposed and validated. The proposed theory explains why a stable radiation pattern can be achieved by this kind of structure. The array model can be used to guide the introduction and optimization of a simplified cross-dipole structure for base station application.
dos Santos, AP & Chaczko, Z 1970, 'Blockchain: Status-Quo, Enablers and Inhibitors', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE, Sydney, Australia.
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Blockchain has been evolving and gaining new heights over the years. The shift in the perspective is allowing new user cases beyond the cryptocurrency space. Cryptocurrencies are digital assets supported by the complexities of cryptography, game theory and peer-to-peer networks. Blockchain became a popular platform for decentralized applications, as well as a valuable tool for start-ups seeking fundraising. The aim of this research paper is to review and assess the status quo for each branch of use cases, and then analyze the enabling and inhibiting factors influencing the adoption of blockchain. These findings permit a broader comprehension over the concepts backing blockchain. It will help new users to establish strategies, develop solutions and encourage the employment of blockchain technology.
Gamal, M, Abolhasan, M, Lipman, J, Liu, RP & Ni, W 1970, 'Multi Objective Resource Optimisation for Network Function Virtualisation Requests', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE, Sydney, Australia.
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© 2018 IEEE. Network function vitalization (NFV) as a new research concept, for both academia and industry, faces many challenges to network operators before it can be accepted into mainstream. One challenge addressed in this paper is to find the optimal placement f or a set of incoming requests with VNF service chains to serve in suitable Virtual Machines (VMs) such that a set of conflicting objectives are met. Mainly, focus is placed on maximizing the total saving cost by increasing the total CPU utilization during the processing time and increasing the processing time for every service request in the cloud network. Moreover, we aim to maximize the admitted traffic simultaneously while considering the system constraints. We formulate the problem as a multi-objective optimization problem and use a Resource Utilization Multi-Objective Evolutionary Algorithm based on Decomposition (RU-MOEA/D) algorithm to solve the problem considering the two objectives simultaneously. Extensive simulations are carried out to evaluate the effects of the different network sizes, genetic parameters and the number of server resources on the acceptable ratio of the arrival chains to serve in the available VMs. The empirical results illustrate that the proposed algorithm can solve the problem efficiently and compute the optimal solution for two objectives together within a reasonable running time.
Gao, X, Du, J, Zhang, T & Guo, YJ 1970, '0.34- THz High-Temperature Superconducting Josephson-Junction Mixer with Superior Noise and Conversion Performance', 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2018 43rd International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz 2018), IEEE, Nagoya, Japan.
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© 2018 IEEE. We present, in this work, a new thin-film antenna-coupled high-temperature superconducting (HTS) Josephson-junction terahertz (THz) mixer that demonstrates superior performance at frequencies around 0.34 THz. A novel dual-meander-slot thin-film antenna is designed to significantly improve the antenna-junction impedance matching and thus more efficient coupling of the THz signal power. Theoretical and experimental investigations are carried out to evaluate the mixer performance. This mixer can be applied to the sensitive THz wireless receivers.
Gao, X, Zhang, T, Du, J & Jay Guo, Y 1970, '300-GHz Dual-Beam Frequency-Selective On-Chip Antenna for High Tc Superconducting Receivers', ISAP 2018 - 2018 International Symposium on Antennas and Propagation, International Symposium on Antennas and Propagation (ISAP), IEEE, Busan, SOUTH KOREA.
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This paper presents a novel terahertz (THz) on-chip antenna design for highT -c superconducting (HTS) heterodyne receiver frontends. The antenna includes a two-element ring-slot array in conjunction with a hemispherical lens, which generates highly-directional dual radiation beams with stable angular separation, thus significantly facilitating the quasi-optics design for coupling radio-frequency (RF) and local oscillator (LO) THz signals. Besides, a double-layered band-pass frequency selective surface (FSS) is designed, and integrated in the THz on-chip antenna to filter out external interferences other than 300-GHz band for maximizing the HTS receiver frontend's noise performance. Numerical simulation shows that the antenna achieves a coupling efficiency of -3.5 dB and a realized gain of 13.5 dB at 300 GHz, and exhibits very stable radiation performance over the whole operating bandwidth of 283 to 316 GHz.
Ghantous, GB & Gill, AQ 1970, 'DevOps Reference Architecture for Multi-cloud IOT Applications.', CBI (1), International Conference on Business Informatics, IEEE Computer Society, Vienna, Austria., pp. 158-167.
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© 2018 IEEE. There is a growing interest among organizations in adopting DevOps approach for IoT (Internet of Things) applications. However, the challenge is: how to apply DevOps when a multi-cloud heterogeneous environment is required for IoT application. This paper aims to addresses this important challenge and proposes a DevOps Reference Architecture (DRA) to deploy IoT-applications on multi-cloud. The proposed architecture is evaluated by the means of a case study, which involves deploying an IoT application on the chosen set of clouds. The results of this initial evaluation indicate that the proposed architecture would help practitioners and researchers to understand the usefulness and applicability of DevOps approach on multi-cloud platform for automating IoT application deployment.
Gorski, T, Bednarski, J & Chaczko, Z 1970, 'Blockchain-based renewable energy exchange management system', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE, Sydney, Australia, Australia, pp. 1-6.
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The paper presents the concept of renewable energy
management system. The idea behind the system is to exploit
the potential of renewable energy generation sources so as
to provide additional energy services and participation in a
competitive energy market. These actions can significantly affect
the shortening of the period of return on investment of individual
customer in renewable energy sources. The paper contains a
concept of Electricity Consumption and Supply Management
System (ECSM) with application of blockchain technology.
ECSM provides functionality to monitor and record continuously
information about inbound and outbound energy to/from power
grid. Except monitoring inbound and outbound energy, solution
will provide the possibility to manage in automatic and manual
way when energy should be sent to energy grid. Information
about inbound/outbound energy will be part of smart contract
which will be confirmed and stored in every node.
Guo, D, Zhao, W, Cui, Y, Wang, Z, Chen, S & Zhang, J 1970, 'Siamese Network Based Features Fusion for Adaptive Visual Tracking', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), International Conference on Artificial Intelligence, Springer International Publishing, China, pp. 759-771.
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© Springer Nature Switzerland AG 2018. Visual object tracking is a popular but challenging problem in computer vision. The main challenge is the lack of priori knowledge of the tracking target, which may be only supervised of a bounding box given in the first frame. Besides, the tracking suffers from many influences as scale variations, deformations, partial occlusions and motion blur, etc. To solve such a challenging problem, a suitable tracking framework is demanded to adopt different tracking scenes. This paper presents a novel approach for robust visual object tracking by multiple features fusion in the Siamese Network. Hand-crafted appearance features and CNN features are combined to mutually compensate for their shortages and enhance the advantages. The proposed network is processed as follows. Firstly, different features are extracted from the tracking frames. Secondly, the extracted features are employed via Correlation Filter respectively to learn corresponding templates, which are used to generate response maps respectively. And finally, the multiple response maps are fused to get a better response map, which can help to locate the target location more accurately. Comprehensive experiments are conducted on three benchmarks: Temple-Color, OTB50 and UAV123. Experimental results demonstrate that the proposed approach achieves state-of-the-art performance on these benchmarks.
Haider, N, Ali, A, He, Y & Dutkiewicz, E 1970, 'Performance Analysis of Full Duplex D2D in Opportunistic Spectrum Access', 2018 18th International Symposium on Communications and Information Technologies (ISCIT), 2018 18th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Bangkok, Thailand, pp. 383-388.
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© 2018 IEEE. Opportunistic Spectrum Access (OSA) allows an efficient use of spectrum based on share-it or use-it principle and can be a viable solution for the challenging problem of spectrum scarcity. Emerging systems have been proposed for OSA, where primary users (PU) have guaranteed interference protection from secondary users (SU). The potential of Full Duplex (FD) and Device-To-device (D2D) technologies in 5G has proven to be promising for increasing data rates and network capacity. In this article using stochastic geometry and random graphs, we model and assess the D2D operations in full Duplex/half Duplex mode for SUs, while protecting the PU's transmission by defining the exclusion zone (EZ). Depending on the location and transmit power of D2D users, the induced aggregate interference should not violate the interference threshold for EZ of PUs. For this, we characterize the interference from D2D links and derive the probability for successful D2D users for half-duplex and full duplex modes. Analyses is further supported by extensive simulations results.
Haihan Sun, Can Ding & Guo, YJ 1970, 'Wideband base station antenna with reduced beam squint', 12th European Conference on Antennas and Propagation (EuCAP 2018), 12th European Conference on Antennas and Propagation (EuCAP 2018), Institution of Engineering and Technology, London, UK.
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© 2018 Institution of Engineering and Technology.All Rights Reserved. This paper presents the design procedure, theoretical analysis, and experimental results of a novel wideband dual-polarized base station antenna. The proposed antenna consists of four electric folded dipoles arranged in an octagon shape that are excited simultaneously for each polarization. It provides the ±45° slant-polarized radiation that meets all the required specifications for base station antenna elements. Experimental results show that the proposed dual-polarized antenna has a wide bandwidth of 46.4% from 1.69 GHz to 2.71 GHz with 15 dB return loss. Across this wide bandwidth, the variations of the half-power-beamwidths (HPBWs) of the two polarizations are all within 66.5° ± 5.5°, port-to-port isolation is > 30 dB, the cross-polarization discrimination (XPD) is > 20 dB and, most importantly, the beam squint is < 4° with a maximum 10° down-tilt.
Hakim, G & Braun, R 1970, 'Agent Based Modeling of a Flange Climb Derailment', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE.
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© 2018 IEEE. We report on the development of an Agent Based Model of a train derailment incident, considering a number of factors including friction and flange angle. We describe the background and objectives, and use the Rushall derailment as a Case Study. We use the NetLogo modeling environment to build our model. We describe the workings of the model. Two scenarios involving frequency of maintenance are tested using the model. We observe unexpected (emergent) results in one case.
Hora, JA, Dura, KDJ, Nabua, CMB, Nericua, RT, Gerasta, OJ, Dutkiewicz, E & Xi, Z 1970, 'A Design of Inverse Class-J Power Amplifier using Varactor Diode for 4G Communication Systems', 2018 IEEE 10th International Conference on Humanoid, Nanotechnology, Information Technology,Communication and Control, Environment and Management (HNICEM), 2018 IEEE 10th International Conference on Humanoid, Nanotechnology, Information Technology,Communication and Control, Environment and Management (HNICEM), IEEE, Baguio City, PHILIPPINES.
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Hora, JA, Piandong, DL, Empas, PEG, Gerasta, OJL, Zhu, X & Dutkiewicz, E 1970, 'A CMOS Implemented Transimpedance Amplifier Design for Optical Communications', 2018 IEEE 10th International Conference on Humanoid, Nanotechnology, Information Technology,Communication and Control, Environment and Management (HNICEM), 2018 IEEE 10th International Conference on Humanoid, Nanotechnology, Information Technology,Communication and Control, Environment and Management (HNICEM), IEEE, Baguio City, Philippines.
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© 2018 IEEE. A transimpedance amplifier for optical communication system is presented in this study. The design includes a regulated cascode and an interleaving active feedback to improve the bandwidth of the transimpedance amplifier. Multiple gain stages are also employed to greatly improve the output voltage. This is implemented in 32 nm CMOS technology using Custom Designer from Synopsys. The circuit is designed to compete with existing transimpedance amplifiers implemented in other technologies in the field of optical communications. The transimpedance amplifier design in this study has a gain of 54 dB and a bandwidth of 9.39 GHz. The layout measures 0.0011mm2 in area and the total power dissipated is 2.94 mW.
Huang, H, Xu, J, Zhang, J, Wu, Q & Kirsch, C 1970, 'Railway Infrastructure Defects Recognition using Fine-grained Deep Convolutional Neural Networks', 2018 Digital Image Computing: Techniques and Applications (DICTA), 2018 Digital Image Computing: Techniques and Applications (DICTA), IEEE, Canberra, Australia.
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© 2018 IEEE. Railway power supply infrastructure is one of the most important components of railway transportation. As the key step of railway maintenance system, power supply infrastructure defects recognition plays a vital role in the whole defects inspection sub-system. Traditional defects recognition task is performed manually, which is time-consuming and high-labor costing. Inspired by the great success of deep neural networks in dealing with different vision tasks, this paper presents an end-to-end deep network to solve the railway infrastructure defects detection problem. More importantly, this paper is the first work that adopts the idea of deep fine-grained classification to do railway defects detection. We propose a new bilinear deep network named Spatial Transformer And Bilinear Low-Rank (STABLR) model and apply it to railway infrastructure defects detection. The experimental results demonstrate that the proposed method outperforms both hand-craft features based machine learning methods and classic deep neural network methods.
Huang, J, Lin, W & Guo, YJ 1970, 'A Ultra-Light High Gain Circularly-Polarized Antenna Array for Mobile Satellite Terminals', 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, IEEE, Boston, MA, USA, pp. 1233-1234.
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© 2018 IEEE. A ultra-light, compact, high gain 16 × 6 CP antenna array is presented in this paper for Ku band mobile satellite applications. The 96-element array consists of 24 2 × 2 CP sub arrays fed by a substrate-integrated-waveguide (SIW) network. Two essential and innovative techniques were adopted in this design. First, in order to achieve the ultra-light weight, the radiation patches were etched on the Polyimide film supported by a patterned foam. A piece of thin SIW network was designed to feed the radiators. The total weight of the fabricated array prototype is only 66.5 gram and profile is low as 0.05 λ0. Second, a sequential rotation (SQR) feeding technique was applied to the aperture fed 2 × 2 CP sub array, which realized more than three times bandwidth enhancement than the direct (non-SQR) feeding approach. In addition, the measured results show the CP-operational bandwidth is 700 MHz from 11.55 to 12.25 GHz. The peak realized gain is 26.4 dBic and gain variation is stable (less than 3 dB) cross the entire operating bandwidth. Be ultra-light and high gain, it is an excellent candidate for Ku band satellite applications.
Huynh, NV, Hoang, DT, Nguyen, DN, Dutkiewicz, E, Niyato, D & Wang, P 1970, 'Reinforcement Learning Approach for RF-Powered Cognitive Radio Network with Ambient Backscatter', 2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings, IEEE Global Communications Conference, IEEE, UAE.
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For an RF-powered cognitive radio network with ambient backscatteringcapability, while the primary channel is busy, the RF-powered secondary user(RSU) can either backscatter the primary signal to transmit its own data orharvest energy from the primary signal (and store in its battery). Theharvested energy then can be used to transmit data when the primary channelbecomes idle. To maximize the throughput for the secondary system, it iscritical for the RSU to decide when to backscatter and when to harvest energy.This optimal decision has to account for the dynamics of the primary channel,energy storage capability, and data to be sent. To tackle that problem, wepropose a Markov decision process (MDP)-based framework to optimize RSU'sdecisions based on its current states, e.g., energy, data as well as theprimary channel state. As the state information may not be readily available atthe RSU, we then design a low-complexity online reinforcement learningalgorithm that guides the RSU to find the optimal solution without requiringprior- and complete-information from the environment. The extensive simulationresults then clearly show that the proposed solution achieves higherthroughputs, i.e., up to 50%, than that of conventional methods.
Jauregi Unanue, I, Zare Borzeshi, E & Piccardi, M 1970, 'A Shared Attention Mechanism for Interpretation of Neural Automatic Post-Editing Systems', Proceedings of the 2nd Workshop on Neural Machine Translation and Generation, Proceedings of the 2nd Workshop on Neural Machine Translation and Generation, Association for Computational Linguistics, Melbourne, Australia, pp. 11-17.
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Automatic post-editing (APE) systems aim to correct the systematic errors made by machine translators. In this paper, we propose a neural APE system that encodes the source (src) and machine translated (mt) sentences with two separate encoders, but leverages a shared attention mechanism to better understand how the two inputs contribute to the generation of the post-edited (pe) sentences. Our empirical observations have showed that when the mt is incorrect, the attention shifts weight toward tokens in the src sentence to properly edit the incorrect translation. The model has been trained and evaluated on the official data from the WMT16 and WMT17 APE IT domain English-German shared tasks. Additionally, we have used the extra 500K artificial data provided by the shared task. Our system has been able to reproduce the accuracies of systems trained with the same data, while at the same time providing better interpretability.
Karmokar, DK, Chen, SL & Guo, YJ 1970, 'Novel Continuous Beam Scanning Leaky-Wave Antennas Using 1-D Mushroom Structure', ISAP 2018 - 2018 International Symposium on Antennas and Propagation, International Symposium on Antennas and Propagation, IEEE, Korea, pp. 753-754.
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Novel continuous backward-to-forward beam-scanning leaky-wave antennas (LWAs) are designed using a 1-D mushroom structure. An effective method is proposed to suppress the bandgap of a mushroom structure. A smooth transition between the backward and forward leaky modes is achievable by choosing a suitable value of the via inductance, and hence the antenna has design flexibility. The study starts from an equivalent circuit of a unit cell and is verified through simulation and measurement. The measured results confirm a continuous 126° beam scan, starting from -60°, with less than 3 dB gain variation. Moreover, the measured 3dB gain bandwidth is over 58%, which is better than most of the reported LWAs.
Kempegowda, SM & Chaczko, Z 1970, 'Essential Skill of Enterprise Architect Practitioners for Digital Era', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE, Sydney, Australia, pp. 1-5.
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The technology landscape has evolved from
Mainframe to Digital platform. In this paper, we are proposing
the skills that are essential for an Enterprise Architect to be
successful in the Digital Era.
Kempegowda, SM & Chaczko, Z 1970, 'Industry 4.0 Complemented with EA Approach: A Proposal for Digital Transformation Success', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE, Sydney, Australia.
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Manufacturing industry based on steam know as
Industry 1.0 is evolving to Industry 4.0 a digital ecosystem
consisting of an interconnected automated system with realtime
data. This paper investigates and proposes, how
the digital ecosystem complemented with Enterprise
Architecture practice will ensure the success of digital
transformation.
Kempegowda, SM & Chaczko, Z 1970, 'The optimum number of Principles ideal for Enterprise Architecture practice', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE, Sydney, Australia, pp. 1-4.
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Every organization defines Principles for Enterprise Architecture (EA) practice. As there is no set standard, the principles identified exceeds the recommended number 20 by TOGAF. More the number of Principles defined it will be ignored by the Enterprise Architects instead referring for their decision making. In this paper, we identify the ideal number of principles that will motivate Architects to refer to perform their task
Khan, AA, Abolhasan, M & Ni, W 1970, '5G next generation VANETs using SDN and fog computing framework', 2018 15th IEEE Annual Consumer Communications & Networking Conference (CCNC), 2018 15th IEEE Annual Consumer Communications & Networking Conference (CCNC), IEEE, Las Vegas, NV, USA, pp. 1-6.
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© 2018 IEEE. The growth of technical revolution towards 5G Next generation networks is expected to meet various communication requirements of future Intelligent Transportation Systems (ITS). Motivated by the consumer needs for variety of ITS applications, bandwidth, high speed and ubiquity, researches are currently exploring different network architectures and techniques, which could be employed in Next generation ITS. To provide flexible network management, control and high resource utilization in Vehicular Ad-hoc Networks (VANETs) on large scale, a new hierarchical 5G Next generation VANET architecture is proposed. The key idea of this holistic architecture is to integrate the centralization and flexibility of Software Defined Networking (SDN) and Cloud-RAN (CRAN), with 5G communication technologies, to effectively allocate resources with a global view. Moreover, a fog computing framework (comprising of zones and clusters) has been proposed at the edge, to avoid frequent handovers between vehicles and RSUs. The transmission delay, throughput and control overhead on controller are analyzed and compared with other architectures. Simulation results indicate reduced transmission delay and minimized control overhead on controllers. Moreover, the throughput of proposed system is also improved.
Klempous, R, Berenguel, M, Chaczko, Z, Rozenblit, JW & Nikodem, J 1970, 'Vitae Summary: Contributions of Prof. Klempous', 2018 IEEE 22nd International Conference on Intelligent Engineering Systems (INES), 2018 IEEE 22nd International Conference on Intelligent Engineering Systems (INES), IEEE, pp. 000011-000012.
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This brief paper presents an overview of the main achievements of Prof. R. Klempous in his collaborations with the Automatic Control, Robotics an Mechatronics research group of CIESOL Center at Universidad de Almeria and the Platforma Solar de Almería, Department of Electrical and Computer Engineering, University of Arizona, Tucson and University of Technology, Sydney.
Le, AT, Nan, Y, Tran, LC, Huang, X, Guo, YJ & Vardaxoglou, Y 1970, 'Analog Least Mean Square Loop for Self-Interference Cancellation in Generalized Continuous Wave SAR', 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), IEEE, Chicago, US, pp. 1-5.
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© 2018 IEEE. Generalized continuous wave synthetic aperture radar (GCW-SAR) is a promising new imaging radar system since it applies the full-duplex (FD) transmission technique to achieve continuous signaling in order to overcome several fundamental limitations of the conventional pulsed SARs. As in any FD wireless communication system, self-interference (SI) is also a key problem which can impact on the GCW-SAR system. In this paper, the analog least mean square (ALMS) loop in the radio frequency domain is adopted to cancel the SI for a GCW-SAR system with periodic chirp signaling. The average residual SI power after the ALMS loop is analyzed theoretically by a stationary analysis. It is found that the ALMS loop not only works with random signals in general FD communication systems, but also works well with the periodic signal in GCW-SAR systems. Simulation results show that over 45 dB SI cancellation can be achieved by the ALMS loop which ensures the proper operation of the GCW-SAR system.
Li, H, Wang, TQ, Huang, X & Guo, YJ 1970, 'Matrix Normalization Based ZF Hybrid Precoded Multi-User MIMO mmWave Systems with Massive Array', 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), 2018 IEEE 88th Vehicular Technology Conference (VTC-Fall), IEEE, Chicago, USA.
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© 2018 IEEE. The superiority of exploring millimeter wave (mmWave) frequencies for future wireless communication systems has pushed forward the development of large-scale antenna arrays for achieving sufficient array gain and high spectral efficiency. In this paper, we study the matrix normalization (MN) based zero-forcing (ZF) hybrid precoding in multi-user multi-input-multi-output (MU-MIMO) mmWave systems. We derive the upper bounds of the achievable rate for two representative hybrid array structures, i.e., fully-connected structure and partially-connected structure. Analytical and simulation results validate the tightness of the proposed performance upper bounds for both hybrid structures using massive array, and provide a comparison of the achievable rate using MN and vector normalization (VN).
Li, M, Cai, YX, Bautista, MG, Yang, Y & Zhu, X 1970, 'Broadband on-chip bandpass filter using ring resonator with capacitive loading', 2018 Australian Microwave Symposium (AMS), 2018 Australian Microwave Symposium (AMS), IEEE, Brisbane, QLD, Australia, pp. 55-56.
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© 2018 IEEE. Design of a broadband on-chip bandpass filter (BPF) using grounded ring resonator with capacitive loading technique is presented in this paper. To prove the concept, a standard 0.13-μm (Bi)-CMOS technology is selected for implementation. To understand how to effectively optimize the designed BPF, parametric studies against some critical parameters are given by means of EM simulation. Finally, the implemented filter is fabricated. The measured results show that the BPF has a center frequency at 33 GHz with a bandwidth of 42.4%. The minimum insertion loss is 2.6 dB, while the stopband rejection is maintained to be better than 20 dB beyond 58 GHz. The chip, excluding the pads, is very compact at only 0.03 mm2 (0.11 × 0.28 mm2).
Li, M, Lin, J-Y, Yang, Y, Zhu, X & Wong, S-W 1970, 'A New Approach of Individually Control of Shorting Posts for Pattern Reconfigurable Antenna Designs', 2018 IEEE International Conference on Computational Electromagnetics (ICCEM), 2018 IEEE International Conference on Computational Electromagnetics (ICCEM), IEEE, Chengdu, China.
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© 2018 IEEE. This paper presents a recently proposed novel approach for pattern reconfigurable antenna designs. Individually associating a shorting post with an RF switch, the shorting post can be simply connected to the ground by turning the switch on or disconnected to the ground by turning the switch off. This approach has been successfully validated through two recently reported designs, for the implementations of transverse magnetic TM mode reconfiguration and 360° beam-steering.
Li, Y, Huang, Y, Xu, R, Seneviratne, S, Thilakarathna, K, Cheng, A, Webb, D & Jourjon, G 1970, 'Deep Content: Unveiling Video Streaming Content from Encrypted WiFi Traffic', 2018 IEEE 17th International Symposium on Network Computing and Applications (NCA), 2018 IEEE 17th International Symposium on Network Computing and Applications (NCA), IEEE, Cambridge, MA, USA.
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© 2018 IEEE. The proliferation of smart devices has led to an exponential growth in digital media consumption, especially mobile video for content marketing. The vast majority of the associated Internet traffic is now end-to-end encrypted, and while encryption provides better user privacy and security, it has made network surveillance an impossible task. The result is an unchecked environment for exploiters and attackers to distribute content such as fake, radical and propaganda videos. Recent advances in machine learning techniques have shown great promise in characterising encrypted traffic captured at the end points. However, video fingerprinting from passively listening to encrypted traffic, especially wireless traffic, has been reported as a challenging task due to the difficulty in distinguishing retransmissions and multiple flows on the same link. We show the potential of fingerprinting videos by passively sniffing WiFi frames in air, even without connecting to the WiFi network. We have developed Multi-Layer Perceptron (MLP) and Recurrent Neural Networks (RNNs) that are able to identify streamed YouTube videos from a closed set, by sniffing WiFi traffic encrypted at both Media Access Control (MAC) and Network layers. We compare these models to the state-of-the-art wired traffic classifier based on Convolutional Neural Networks (CNNs), and show that our models obtain similar results while requiring significantly less computational power and time (approximately a threefold reduction).
Li, Z, Yao, L, Nie, F, Zhang, D & Xu, M 1970, 'Multi-rate gated recurrent convolutional networks for video-based pedestrian re-identification', 32nd AAAI Conference on Artificial Intelligence, AAAI 2018, AAAI Conference on Artifical Intelligence, AAAI, New Orleans, Lousiana, USA, pp. 7081-7088.
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Matching pedestrians across multiple camera views has attracted lots of recent research attention due to its apparent importance in surveillance and security applications. While most existing works address this problem in a still-image setting, we consider the more informative and challenging video-based person re-identification problem, where a video of a pedestrian as seen in one camera needs to be matched to a gallery of videos captured by other non-overlapping cameras. We employ a convolutional network to extract the appearance and motion features from raw video sequences, and then feed them into a multi-rate recurrent network to exploit the temporal correlations, and more importantly, to take into account the fact that pedestrians, sometimes even the same pedestrian, move in different speeds across different camera views. The combined network is trained in an end-to-end fashion, and we further propose an initialization strategy via context reconstruction to largely improve the performance. We conduct extensive experiments on the iLIDS-VID and PRID-2011 datasets, and our experimental results confirm the effectiveness and the generalization ability of our model.
Li, Z, Zhang, J, Wu, Q & Kirsch, C 1970, 'Field-Regularised Factorization Machines for Mining the Maintenance Logs of Equipment', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Australasian Joint Conference on Artificial Intelligence, Springer International Publishing, New Zealand, pp. 172-183.
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© Springer Nature Switzerland AG 2018. Failure prediction is very important for railway infrastructure. Traditionally, data from various sensors are collected for this task. Value of maintenance logs is often neglected. Maintenance records of equipment usually indicate equipment status. They could be valuable for prediction of equipment faults. In this paper, we propose Field-regularised Factorization Machines (FrFMs) to predict failures of railway points with maintenance logs. Factorization Machine (FM) and its variants are state-of-the-art algorithms designed for sparse data. They are widely used in click-through rate prediction and recommendation systems. Categorical variables are converted to binary features through one-hot encoding and then fed into these models. However, field information is ignored in this process. We propose Field-regularised Factorization Machines to incorporate such valuable information. Experiments on data set from railway maintenance logs and another public data set show the effectiveness of our methods.
Lin, J-Y, Li, M, Wong, S-W, Yang, Y & Zhu, X 1970, 'A cavity triple-mode filter with excitation of L-shape model', 2018 Australian Microwave Symposium (AMS), 2018 Australian Microwave Symposium (AMS), IEEE, Brisbane, Australia, pp. 17-18.
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© 2018 IEEE. A triple-mode cavity filter with narrow passband realized in a single rectangular metal cavity without any tune crews, coupling apertures, iris, and corner cuts is proposed in this paper, while three resonant modes are classified as a TM mode and a pair of TE modes, which are excited by two metal probes in one single cavity. At both the upper and lower stop-bands, two transmission zeros are created to achieve a considerable out-of-band suppression. To prove the concept, a prototype is fabricated by using the silver plated aluminum technology demonstrating a measured fractional bandwidth of 3.6% at the center frequency of 2.53 GHz. The measured and simulated results are presented in good agreement.
Liu, F, Liu, Y, Guo, YJ & Liu, QH 1970, 'Synthesis of Rotated Sparse Linear Dipole Array with Shaped Power Pattern', 2018 International Applied Computational Electromagnetics Society Symposium - China (ACES), 2018 International Applied Computational Electromagnetics Society Symposium - China (ACES), IEEE, Beijing, China.
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© 2018 ACES. A new shaped pattern synthesis method is presented in which element rotations, positions and phases are co-optimized to produce a shaped beam pattern for a sparse dipole array. Compared with conventional shaped pattern synthesis using excitation amplitude and phase optimization, the proposed method can not only reduce the number of elements But also avoid the usage of unequal power dividers. A synthesis example is provided to verify the performance of the proposed method.
Luo, Q, Liu, Y, Liu, F, Ren, Y & Guo, YJ 1970, 'Fast Synthesis Algorithm for Uniformly Spaced Circular Array with Low Sidelobe Pattern', 2018 International Applied Computational Electromagnetics Society Symposium - China (ACES), 2018 International Applied Computational Electromagnetics Society Symposium - China (ACES), IEEE, Beijing, China.
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© 2018 ACES. In this paper, a highly efficient approach is proposed to synthesize the low sidelobe pattern of uniformly spaced circular array. The proposed approach can be generalized to deal with the pattern synthesis for the circular array with directional elements. Numerical examples are given to verify the effectiveness and advantage of this approach.
Mai, H, Pham, TT, Nguyen, DN & Dutkiewicz, E 1970, 'Non-Laboratory-Based Risk Factors for Automated Heart Disease Detection', 2018 12th International Symposium on Medical Information and Communication Technology (ISMICT), 2018 12th International Symposium on Medical Information and Communication Technology (ISMICT), IEEE, Sydney, Australia.
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Developing a heart disease detection model using simple non-laboratory risk factors plays an important role in preventive care, especially for high risk subjects. The model allows physicians/epidemiologists to effectively diagnose a person as having heart disease. In this work, we aim to develop a non-invasive risk prediction model for automated heart disease detection that involves age, gender, rest blood pressure, maximum heart rate, and rest electrocardiography. We examine four public datasets from 1071 participants who were referred for a special X-ray of the heart's arteries (i.e., to see if they are narrowed or blocked). The subjects also undertook a physical examination and three non-invasive tests. To estimate the heart disease status, we apply a generalized linear model with regularization paths via coordinate descent. Even without laboratory-based data (e.g., serum cholesterol, fasting blood sugar), we observed a prediction accuracy as high as 72%, compared with 76% of other comprehensive models. This observation suggests that few non-invasive factors utilizing recent advances in data analytics can replace the current practices of heart disease risk assessment.
Makhdoom, I, Abolhasan, M & Ni, W 1970, 'Blockchain for IoT: The Challenges and a Way Forward', Proceedings of the 15th International Joint Conference on e-Business and Telecommunications, International Conference on Security and Cryptography, SCITEPRESS - Science and Technology Publications, Porto, Portugal, pp. 428-439.
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Bitcoin has revolutionized the decentralized payment system by excluding the need for a trusted third party, reducing the transaction (TX) fee and time involved in TX confirmation as compared to a conventional banking system. The underlying technology of Bitcoin is Blockchain, which was initially designed for financial TXs only. However, due to its decentralized architecture, fault tolerance and cryptographic security benefits such as user anonymity, data integrity and authentication, researchers and security analysts around the world are focusing on the Blockchain to resolve security and privacy issues of IoT. But at the same time, default limitations of Blockchain, such as latency in transaction confirmation, scalability concerning Blockchain size and network expansion, lack of IoT-centric transaction validation rules, the absence of IoT-focused consensus protocols and insecure device integration are required to be addressed before it can be used securely and efficiently in an IoT e nvironment. Therefore, in this paper we analyze some of the existing consensus protocols used in various Blockchain-based applications, with a focus on investigating significant limitations in TX (Transaction) validation and consensus mechanism that make them inappropriate to be implemented in Blockchain-based IoT systems. We also propose a way forward to address these issues.
Makhdoom, I, Abolhasan, M & Ni, W 1970, 'Blockchain for IoT: The Challenges and a Way Forward', Proceedings of the 15th International Joint Conference on e-Business and Telecommunications, International Conference on Security and Cryptography, SCITEPRESS - Science and Technology Publications.
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Mehar, AM, Gill, AQ & Matawie, KM 1970, 'Analytical Model for Residential Predicting Energy Consumption.', CBI (2), IEEE Conference on Business Informatics BAPAR Workshops, IEEE Computer Society, Vienna, Austria, pp. 82-88.
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© 2018 IEEE. Effective energy consumption prediction is important for determining the demand and supply of energy. The challenge is how to predict energy consumption? This study presents an energy consumption analytical regression model and process based on the project conducted in an Australian company. This study involved the analysis of household and energy consumption datasets in the residential sector. The analytical model generation process is organised into four major stages: prepared the household and energy consumption data or data cleansing, household energy consumption clustering (segmentation or groups) using k-means clustering algorithm for similarity measure in their characteristics, stepwise multiple regression for variables selection to determine the final model's predictors, and filter the final regression model to identify the influential observations using Cook's distance and Q-Q (quantile-quantile) normal plot for improvement in the model. The final filtered regression model represents 64 percent variation to the dependent variable is explained by independent variables with correlation 0.8 between energy consumption observed and predicted values. The abovementioned process and resultant regression model seem useful for developing household energy consumptions models for managing the demand and supply of energy.
More, FJ & Chaczko, Z 1970, 'Non-invasive Methods in the Detection of Coronary Artery Disease', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE, Sydney, Australia, pp. 1-5.
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Coronary Artery Disease (CAD) is the prime causal factor in cardiovascular disease in the 21st century throughout the world. In Australia, CAD related diseases result in 12% morbidity and mortality rate. This paper summarizes the non-invasive methods of diagnosis of CAD. The association between medical science and biomedical engineering has led to the development of non-invasive methods of diagnosis of CAD. The use of new technology that exploits IoT and Body Area Networks using wearable sensor devices over the patient’s body and medical experts to diagnose CAD. Progression of clinical assessment, diagnosis, and evaluation of CAD have been achieved in the last decade. The current treatment plan for CAD focused on clinical prevention, surgical or a combination of both depending on the severity of disease. The analysis of coronary artery disease, chest pain, and various things involved in the assessment of patient’s history with relieving factors such as risk stratification and non-invasive tests used in diagnosis of CAD.
Ni, Z, Zhang, JA, Yang, K, Gao, F & Gao, Z 1970, 'Codebook Based Minimum Subspace Distortion Hybrid Precoding for Millimeter Wave Systems', 2018 IEEE Globecom Workshops (GC Wkshps), 2018 IEEE Globecom Workshops (GC Wkshps), IEEE, Abu Dhabi, United Arab Emirates.
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© 2018 IEEE. Hybrid precoding is adopted for millimeter wave (mmWave) communications to offer a good trade-off between hardware complexity and system performance. In this paper, we investigate a codebook based hybrid precoder for single-user mmWave systems with large antenna arrays. We exploit the sparse nature of mmWave channels to transform the hybrid precoding design problem into a vector space distortion optimization problem which is only related to the radio frequency (RF) precoder. A near optimal solution for the RF optimization problem is derived with the assumption of the perfect channel state information (CSI) at the transmitter, which is practically very difficult to obtain. To reduce the requirement of the CSI at the transmitter, we propose the codebook based minimum subspace distortion (MSD) hybrid precoding algorithm, which obtains CSI at the combiner side and returns the index of optimal RF codewords and the baseband precoder through a limited feedback channel. Simulation results are provided and validate the effectiveness of our proposed hybrid precoding algorithm.
Pham, TT, Nguyen, DN, Dutkiewicz, E, McEwan, AL, Leong, PHW & Fuglevand, AJ 1970, 'Feature Analysis for Discrimination of Motor Unit Action Potentials', 2018 12TH INTERNATIONAL SYMPOSIUM ON MEDICAL INFORMATION AND COMMUNICATION TECHNOLOGY (ISMICT), 12th International Symposium on Medical Information and Communication Technology (ISMICT), IEEE, Univ Technol, Sydney, AUSTRALIA, pp. 18-23.
Pham, TT, Nguyen, DN, Dutkiewicz, E, McEwan, AL, Leong, PHW & Fuglevand, AJ 1970, 'Feature Analysis for Discrimination of Motor Unit Action Potentials', 2018 12th International Symposium on Medical Information and Communication Technology (ISMICT), 2018 12th International Symposium on Medical Information and Communication Technology (ISMICT), IEEE, Sydney, Australia.
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Poostchi, H & Piccardi, M 1970, 'Cluster Labeling by Word Embeddings and WordNet’s Hypernymy', https://www.aclweb.org/anthology/U18-1, Annual Workshop of The Australasian Language Technology Association, Dunedin, New Zealand.
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Cluster labeling is the assignment of representative labels to clusters of documents or words. Once assigned, the labels can play an important role in applications such as navigation, search and document classification. However, finding appropriately descriptive labels is still a challenging task. In this paper, we propose various approaches for assigning labels to word clusters by leveraging word embeddings and the synonymy and hypernymy relations in the WordNet lexical ontology. Experiments carried out using the WebAP document dataset have shown that one of the approaches stand out in the comparison and is capable of selecting labels that are reasonably aligned with those chosen by a pool of four human annotators.
Poostchi, H, Borzeshi, EZ & Piccardi, M 1970, 'BiLSTM-CRF for Persian Named-Entity Recognition', PROCEEDINGS OF THE ELEVENTH INTERNATIONAL CONFERENCE ON LANGUAGE RESOURCES AND EVALUATION (LREC 2018), 11th International Conference on Language Resources and Evaluation (LREC), EUROPEAN LANGUAGE RESOURCES ASSOC-ELRA, JAPAN, Miyazaki, pp. 4427-4431.
Qureshi, S & Braun, R 1970, 'Dynamic Light Path Establishment In switch Fabric Using OpenFlow', 2018 26th International Conference on Systems Engineering (ICSEng), 2018 26th International Conference on Systems Engineering (ICSEng), IEEE, Sydney, Australia.
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© 2018 IEEE. In today's optical networks, Light paths are established through Network Management System and Element Management System, which is a manual and cumbersome process. Paths are computed and pre-setup according to the known traffic d emands, a nd p rovisioning a ny new service takes time. Several efforts have recently been made to make the path establishment process dynamic, including the Software Defined N etworking a pproach. H owever all of this work has assumed fully interconnected fabrics of the network devices which is generally not the case. The task of end to end path establishment between network elements and through fabric are interrelated, and this task remains incomplete, without consideration of the switch's limitations. This work highlights for the first time the issue of path establishment dynamically through a switch fabric. The paper briefly e xplains t he p roblem a nd s uggests an SDN based solution using the OpenFlow protocol. This work contributes a represention of the basic framework which will be required to make the complete path setup process dynamic. The paper also includes an operational description.
Ranglund, OJ, Haave, H, Venemyr, GO, Vold, T & Braun, R 1970, 'Gaming and scenario building: A student active approach to learning', Proceedings of the European Conference on Games-based Learning, 12th European Conference on Games Based Learning (ECGBL), ACAD CONFERENCES LTD, SKEMA Business Sch, FRANCE, pp. 526-531.
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Students like to learn from gaming if the game has a learning objective they can recognize. In this paper we present research done at a course in a Bachelor in Crisis Management and Communication at The Inland Norway University of Applied Sciences. The course consists of several two-day seminars. The assignment was handed out at the first seminar. The objective of the assignment was to develop a playable scenario for one of three platforms; Rayvn, HoloLens and Virtual Battle Space3-platform (VBS3). On the VBS3-platform from Bohemia Interactive Solutions, a town is programmed with houses, vehicles, avatars, hospitals, and a number of other features. The town is called “Lyngvik”, and all bad things happen here; fires, landslides, explosions, to mention a few. Rayvn is an incident management tool. This text based tool was interesting to test out as a tool also for the simulating/gaming. HoloLens from Microsoft was maybe the most spectacular tool to test. The 3D view and possibilities this tool offered as a tool for executing a crisis management situation was highly interesting. The students were offered advising sessions to make sure that the scenarios were playable for the tools chosen. Our data are collected from researcher’s observations, and interviews with the students. These qualitative ways of collecting data during the two-day gaming session, gave us valuable insight into how this way of offering education provided the students with a safe and fun arena to learn more from. The preliminary results have been very positive. Even if the students were hesitant when receiving the assignment, the engagement they showed when gaming and simulating, were unmistakably. Technical issues with the VBS3-platform sometimes broke flow as the game needed restarting. Also, there were students that were unfamiliar with how to move avatars and vehicles. They learned this during the session. These are issues we need to take into account, and resolve for future use of th...
Seifollahi, S, Piccardi, M & Borzeshi, EZ 1970, 'A Semi-supervised Hidden Markov Topic Model Based on Prior Knowledge', Communications in Computer and Information Science, Australasian Data Mining Conference, Springer Singapore, Melbourne, VIC, Australia,, pp. 265-276.
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© Springer Nature Singapore Pte Ltd. 2018. A topic model is an unsupervised model to automatically discover the topics discussed in a collection of documents. Most of the existing topic models only use bag-of-words representations or single-word distributions and do not consider relations between words in the model. As a consequence, these models may generate topics which are not in good agreement with human-judged topic coherence. To mitigate this issue, we present a topic model which employs topically-related knowledge from prior topics and words’ co-occurrence/relations in the collection. To incorporate the prior knowledge, we leverage a two-staged semi-supervised Markov topic model. In the first stage, we estimate a transition matrix and a low-dimensional vocabulary for the final topic model. In the second stage, we produce the final topic model where the topic assignment is performed following a Markov chain process. Experiments on real text documents from a major compensation agency demonstrate improvements of both the PMI score measure and the topic coherence.
Shen, J, Wang, Y & Zhang, J 1970, 'Memory Optimized Deep Dense Network for Image Super-resolution', 2018 Digital Image Computing: Techniques and Applications (DICTA), 2018 Digital Image Computing: Techniques and Applications (DICTA), IEEE, Canberra, Australia.
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CNN methods for image super-resolution consume a large number of training-time memory, due to the feature size will not decrease as the network goes deeper. To reduce the memory consumption during training, we propose a memory optimized deep dense network for image super-resolution. We first reduce redundant features learning, by rationally designing the skip connection and dense connection in the network. Then we adopt share memory allocations to store concatenated features and Batch Normalization intermediate feature maps. The memory optimized network consumes less memory than normal dense network. We also evaluate our proposed architecture on highly competitive super-resolution benchmark datasets. Our deep dense network outperforms some existing methods, and requires relatively less computation.
Shi, Z, Xu, M, Pan, Q, Yan, B & Zhang, H 1970, 'LSTM-based Flight Trajectory Prediction', 2018 International Joint Conference on Neural Networks (IJCNN), 2018 International Joint Conference on Neural Networks (IJCNN), IEEE, Rio de Janeiro, Brazil.
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Safety ranks the first in Air Traffic Management (ATM). Accurate trajectory prediction can help ATM to forecast potential dangers and effectively provide instructions for safely traveling. Most trajectory prediction algorithms work for land traffic, which rely on points of interest (POIs) and are only suitable for stationary road condition. Compared with land traffic prediction, flight trajectory prediction is very difficult because way-points are sparse and the flight envelopes are heavily affected by external factors. In this paper, we propose a flight trajectory prediction model based on a Long Short-Term Memory (LSTM) network. The four interacting layers of a repeating module in an LSTM enables it to connect the long-term dependencies to present predicting task. Applying sliding windows in LSTM maintains the continuity and avoids compromising the dynamic dependencies of adjacent states in the long-term sequences, which helps to improve accuracy of trajectory prediction. Taking time dimension into consideration, both 3-D (time stamp, latitude and longitude) and 4-D (time stamp, latitude, longitude and altitude) trajectories are predicted to prove the efficiency of our approach. The dataset we use was collected by ADS-B ground stations. We evaluate our model by widely used measurements, such as the mean absolute error (MAE), the mean relative error (MRE), the root mean square error (RMSE) and the dynamic warping time (DWT) methods. As Markov Model is the most popular in time series processing, comparisons among Markov Model (MM), weighted Markov Model (wMM) and our model are presented. Our model outperforms the existing models (MM and wMM) and provides a strong basis for abnormal detection and decision-making.
Shi, Z, Zhang, JA, Xu, R & Fang, G 1970, 'Human Activity Recognition Using Deep Learning Networks with Enhanced Channel State Information', 2018 IEEE Globecom Workshops (GC Wkshps), 2018 IEEE Globecom Workshops (GC Wkshps), IEEE, Abu Dhabi, United Arab Emirates.
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© 2018 IEEE. Channel State Information (CSI) is widely used for device free human activity recognition. Feature extraction remains as one of the most challenging tasks in a dynamic and complex environment. In this paper, we propose a human activity recognition scheme using Deep Learning Networks with enhanced Channel State information (DLN-eCSI). We develop a CSI feature enhancement scheme (CFES), including two modules of background reduction and correlation feature enhancement, for preprocessing the data input to the DLN. After cleaning and compressing the signals using CFES, we apply the recurrent neural networking (RNN) to automatically extract deeper features and then the softmax regression algorithm for activity classification. Extensive experiments are conducted to validate the effectiveness of the proposed scheme.
Shu-Lin Chen, Wei Lin, Pei-Yuan Qin, Guo, YJ & Ziolkowski, RW 1970, 'Novel Low-Profile Wideband Reconfigurable CP Antenna Array', 12th European Conference on Antennas and Propagation (EuCAP 2018), 12th European Conference on Antennas and Propagation (EuCAP 2018), Institution of Engineering and Technology, UK.
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© Institution of Engineering and Technology.All Rights Reserved. For future wireless communications, cost-effective, low-profile circular polarization (CP) antennas with wide bandwidth and high directivity are highly desirable to increase system capacity and suppress polarization mismatch. In this paper, a wideband circular polarization antenna array integrated with a polarization-independent artificial magnetic conductor (AMC) is reported that meets the demands. First, a wideband CP reconfigurable antenna with a pair of cross-bowtie radiators and a metal ground is presented to achieve a fractional bandwidth of 35.9%. By replacing the metal ground with a polarization-independent AMC ground, the antenna profile is reduced from 0.25λ0 to 0.05λ0 with only a slight bandwidth decrease. A wideband CP reconfigurable 4-element linear array is achieved using four of those elements. It is low profile (0.05 λ0), and has a wide operating bandwidth (21.7%), and a high realized gain (13 dBic).
Simorangkir, RBVB, Mengze Li, Yang Yang, Xu, K, Esselle, K & Dutkiewicz, E 1970, '360-Degree Polarization Scanning with the Diversity of Boresight and Conical Patterns Switching', 12th European Conference on Antennas and Propagation (EuCAP 2018), 12th European Conference on Antennas and Propagation (EuCAP 2018), Institution of Engineering and Technology, London, UK.
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© 2018 Institution of Engineering and Technology.All Rights Reserved. A novel reconfigurable antenna with the capability of 360-degree polarization scanning and the diversity of boresight and conical radiation patterns switching is presented in this paper. Each shorting-post is connected and controlled by a PIN diode to achieve the desired distribution of electric field null(s) in the substrate, where transverse magnetic (TM) modes switching between TM11 and TM02 can be accordingly realized corresponding to boresight and conical patterns. The antenna is analyzed in a cavity model, which, in terms of electric field, theoretically explains the generation of TM11 and TM02 resonant modes, and provides the audience with an innovative method of designing pattern reconfigurable antennas for the applications such as multiple-input and multiple-output (MIMO), wireless body sensor network (WBSN), Wi-Fi and WiMAX. The proposed antenna is with a competitive radius of 0.32 λg. The antenna structure is very easy to be fabricated. The measurement shows that the antenna can realize a boresight and conical pattern reconfiguration at 2.4 GHz with a gain of 6 dBi and efficiency of 86.7% (boresight mode), and 4.39 dBi and efficiency of 82.4% (conical mode).
Sun, H, Ding, C, Bird, TS & Guo, YJ 1970, 'A base station antenna element with simple structure but excellent performance', 2018 Australian Microwave Symposium (AMS), 2018 Australian Microwave Symposium (AMS), IEEE, Brsibane, QLD, Australia, pp. 35-36.
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© 2018 IEEE. A ±45° dual-polarized concentrically arranged dipole antenna is proposed for base station applications. The simple, robust antenna consists of four simple dipoles arranged in a square above a flat reflector. Two specially designed feeding networks for the two polarizations are proposed to simultaneously excite the four dipoles. Without shaping the reflector, the combination of four dipoles provides a stable radiation pattern across a wide bandwidth. Measured results show that the proposed antenna has an input reflection coefficient ≤ -14 dB from 1.71 to 2.71 GHz for both polarizations. Across this wide bandwidth (45.2%), the half-power-beamwidths (HPBWs) of the two polarizations remain very stable in the range from 60.5° to 69.5°. High port-to-port isolation ≥ 30 dB and low cross-polarization level ≤ -20 dB are achieved over the entire operating band.
Sun, H, Ding, C, Yang, T, Guo, YJ & Qin, P 1970, 'A wideband base station antenna with stable radiation pattern', 2018 Australian Microwave Symposium (AMS), 2018 Australian Microwave Symposium (AMS), IEEE, Brisbane, QLD, Australia, pp. 5-6.
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© 2018 IEEE. This paper presents the configuration and experimental results of a novel wideband dual-polarized base station antenna with superior performance. The proposed antenna consists of four electric folded dipoles arranged in an octagon shape that are excited simultaneously for each polarization. Experimental results show that this element has a wide bandwidth of 46.4% from 1.69 GHz to 2.71 GHz with ≥ 15 dB return loss. Across this wide band, the variations of the half-power-beamwidths (HPBWs) of the two polarizations are all within 66.5° ± 5.5°, the port-to-port isolation is > 28 dB, and the cross-polarization discrimination (XPD) is > 25 dB.
Sun, H-H, Ding, C & Guo, YJ 1970, 'A Novel Dual-Polarized Planar Antenna', 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, 2018 IEEE International Symposium on Antennas and Propagation & USNC/URSI National Radio Science Meeting, IEEE, Boston, MA, USA, pp. 2185-2186.
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© 2018 IEEE. A wideband dual-polarized antenna with a novel planar configuration is presented for base station applications. Two groups of simple dipoles are fed by two microstrip feed networks to achieve ±45° polarizations. A novel feeding technique that leads to a planar configuration is described. Measured results show that excellent matching and stable radiation performances are achieved over a wide band.
Tofigh, F, Mao, G, Lipman, J & Abolhasan, M 1970, 'Crowd Density Mapping Based on Wi-Fi Measurements on Train Platforms', 2018 12th International Conference on Signal Processing and Communication Systems (ICSPCS), 2018 12th International Conference on Signal Processing and Communication Systems (ICSPCS), IEEE, Cairns, Australia.
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© 2018 IEEE. Crowd distribution is a challenging issue in the management and design levels. This paper provides a passive method to derive the crowd density distribution using Wi-Fi measurements on a real scenario. Six WiFi access points (AP) are deployed in the platform 2/3 of Redfern station, Sydney to monitor the platform for a week. Based on the probability maps that are built using RSSI measurements and prior knowledge, the crowd distribution is calculated on the platform and its results are compared with distributions acquired from CCTV images. Final density heat maps are in good agreement with the acquired results from CCTV cameras.
Vold, T, Haave, H, Ranglund, OJS, Venemyr, GO, Bakken, BT, Kionig, L & Braun, R 1970, 'Flipped Gaming - testing three simulation games', 2018 17th International Conference on Information Technology Based Higher Education and Training (ITHET), 2018 17th International Conference on Information Technology Based Higher Education and Training (ITHET), IEEE, Olhao, Portugal, pp. 1-6.
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© 2018 IEEE. At the Inland Norway University of Applied Sciences 'flipped gaming' has been tested with two student groups (in 2017). This paper will present a newer version of the 'flipping' and also how a total of eight groups utilized tree different types of simulators to play the scenarios. The scenarios were developed by the student themselves as this was their mandatory assignment. The mandatory assignment was handed out in January. The assignment was about making a playable script for an incident, in addition to conduct the planning, execution and evaluation of a complete exercise in crisis management. They were given feedback once before the workshop where they presented and played the script. The tools that were used was Rayvn (https://rayvn.global/), Microsoft HoloLens (https://www.microsoft.com/nb-no/hololens) and a simulator based on a platform from Bohemia Interactive Solutions (https://bisimulations.com/)-the same platform as Virtual Battle Space 3 uses. Rayvn is an incident management tool, mainly for communication. The written messages can then be logged and stored for later reflections. Microsoft HoloLens is a tool for 3D vision, a tool that can show environments in 3D and allow the player to carry out operations using movements that are recorded and executed. This was a prototype. The game based simulator is computer based. The different views are 2D maps and 3D environments. The players use the keyboard and mouse to move the vehicles and avatars around. This in a 'disaster town', called 'Lyngvik', a very poor planned city centre with a large accident/crisis potential. The study is based on the previous study of the learning outcome from assignment that is based on student input. The mandatory assignment was to develop a playable scenario and they could choose in which of the three different simulation tools they were to play their scenario. Two by two, the groups are to play each other's scenario. They have received some supervision an...
Vu, L, Thuy, HV, Nguyen, QU, Ngoc, TN, Nguyen, DN, Hoang, DT & Dutkiewicz, E 1970, 'Time Series Analysis for Encrypted Traffic Classification: A Deep Learning Approach', 2018 18th International Symposium on Communications and Information Technologies (ISCIT), 2018 18th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Bangkok, Thailand, pp. 121-126.
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© 2018 IEEE. We develop a novel time series feature extraction technique to address the encrypted traffic/application classification problem. The proposed method consists of two main steps. First, we propose a feature engineering technique to extract significant attributes of the encrypted network traffic behavior by analyzing the time series of receiving packets. In the second step, we develop a deep learning-based technique to exploit the correlation of time series data samples of the encrypted network applications. To evaluate the efficiency of the proposed solution on the encrypted traffic classification problem, we carry out intensive experiments on a raw network traffic dataset, namely VPN-nonVPN, with three conventional classifier metrics including Precision, Recall, and F1 score. The experimental results demonstrate that our proposed approach can significantly improve the performance in identifying encrypted application traffic in terms of accuracy and computation efficiency.
Vu, TT, Huynh, NV, Hoang, DT, Nguyen, DN & Dutkiewicz, E 1970, 'Offloading Energy Efficiency with Delay Constraint for Cooperative Mobile Edge Computing Networks', 2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings, IEEE Global Communications Conference, Abu Dhabi, United Arab Emirates.
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We propose a novel edge computing network architecture that enables edgenodes to cooperate in sharing computing and radio resources to minimize thetotal energy consumption of mobile users while meeting their delayrequirements. To find the optimal task offloading decisions for mobile users,we first formulate the joint task offloading and resource allocationoptimization problem as a mixed integer non-linear programming (MINLP). Theoptimization involves both binary (offloading decisions) and real variables(resource allocations), making it an NP-hard and computational intractableproblem. To circumvent, we relax the binary decision variables to transform theMINLP to a relaxed optimization problem with real variables. After proving thatthe relaxed problem is a convex one, we propose two solutions namely ROP andIBBA. ROP is adopted from the interior point method and IBBA is developed fromthe branch and bound algorithm. Through the numerical results, we show that ourproposed approaches allow minimizing the total energy consumption and meet alldelay requirements for mobile users.
Vu, TT, Nguyen, DN & Dutkiewicz, E 1970, '2D Proactive Uplink Resource Allocation Algorithm for Event Based MTC Applications', IEEE Wireless Communications and Networking Conference (WCNC), IEEE, Barcelona, Spain.
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We propose a two dimension (2D) proactive uplink resource allocation(2D-PURA) algorithm that aims to reduce the delay/latency in event-basedmachine-type communications (MTC) applications. Specifically, when an event ofinterest occurs at a device, it tends to spread to the neighboring devices.Consequently, when a device has data to send to the base station (BS), itsneighbors later are highly likely to transmit. Thus, we propose to clusterdevices in the neighborhood around the event, also referred to as thedisturbance region, into rings based on the distance from the original event.To reduce the uplink latency, we then proactively allocate resources for theserings. To evaluate the proposed algorithm, we analytically derive the meanuplink delay, the proportion of resource conservation due to successfulallocations, and the proportion of uplink resource wastage due to unsuccessfulallocations for 2D-PURA algorithm. Numerical results demonstrate that theproposed method can save over 16.5 and 27 percent of mean uplink delay,compared with the 1D algorithm and the standard method, respectively.
Wang, H, Nguyen, DN, Hoang, DT, Dutkiewicz, E & Cheng, Q 1970, 'Real-Time Crowdsourcing Incentive for Radio Environment Maps: A Dynamic Pricing Approach', 2018 IEEE Global Communications Conference (GLOBECOM), GLOBECOM 2018 - 2018 IEEE Global Communications Conference, IEEE, UAE.
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© 2018 IEEE. To effectively utilize/harvest short-lived whitespace that accounts for more than 30% of the cellular bands, it is critical to build a real-time radio environment map. Note that existing radio spectrum maps/databases (e.g., Google Spectrum Database) are updated on a daily or weekly basis. In this paper, we introduce a novel real-time crowdsourcing incentive solution that rewards mobile users who contribute their qualified spectrum sensing data to a radio environment map. First, we develop a feature-based model based on advanced machine learning techniques in order to estimate model parameters of the radio environment map. Based on the prediction model, we then propose a smart dynamic pricing strategy including prepaid and postpaid pricing schemes. The prepaid scheme is to guarantee the minimum payment for participants, and the postpaid scheme is to reward the participants according to their contributions. Importantly, in our model, the postpaid scheme will be adjusted iteratively in a real-time manner based on the contributions of participants to the spectrum map. After that we carry out real experiments through a mobile application and a cloud spectrum database. The experiment results show that our proposed solution can achieve not only better users' utilities, but also a lower overall system cost compared with those of some existing works.
Wang, X, Zha, X, Yu, G, Ni, W, Liu, RP, Guo, YJ, Niu, X & Zheng, K 1970, 'Attack and Defence of Ethereum Remote APIs', 2018 IEEE Globecom Workshops (GC Wkshps), 2018 IEEE Globecom Workshops (GC Wkshps), IEEE, Abu Dhabi, United Arab Emirates, United Arab Emirates.
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© 2018 IEEE. Ethereum, as the first Turing-complete blockchain platform, provides various application program interfaces for developers. Although blockchain has highly improved security, faulty configuration and usage can result in serious vulnerabilities. In this paper, we focus on the security vulnerabilities of the official Go-version Ethereum client (geth). The vulnerabilities are because of the insecure API design and the specific Ethereum wallet mechanism. We demonstrate attacks exploiting these vulnerabilities in an Ethereum testbed. The vulnerabilities are confirmed by the scanning results on the public Internet. Finally, corresponding countermeasures against attacks are provided to enhance the security of the Ethereum platform.
Wang, Y, Shen, J & Zhang, J 1970, 'Deep Bi-Dense Networks for Image Super-Resolution', 2018 INTERNATIONAL CONFERENCE ON DIGITAL IMAGE COMPUTING: TECHNIQUES AND APPLICATIONS (DICTA), International Conference on Digital Image Computing - Techniques and Applications (DICTA), IEEE, AUSTRALIA, Canberra, pp. 404-411.
Wang, Y, Shen, J & Zhang, J 1970, 'Deep Bi-Dense Networks for Image Super-Resolution', 2018 Digital Image Computing: Techniques and Applications (DICTA), 2018 Digital Image Computing: Techniques and Applications (DICTA), IEEE, Canberra.
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This paper proposes Deep Bi-Dense Networks (DBD-N) for single image super-resolution. Our approach extends previous intra-block dense connection approaches by including novel inter-block dense connections. In this way, feature information propagates from a single dense block to all subsequent blocks, instead of to a single successor. To build a DBDN, we firstly construct intra-dense blocks, which extract and compress abundant local features via densely connected convolutional layers and compression layers for further feature learning. Then, we use an inter-block dense net to connect intra-dense blocks, which allow each intra-dense block propagates its own local features to all successors. Additionally, our bi-dense construction connects each block to the output, alleviating the vanishing gradient problems in training. The evaluation of our proposed method on five benchmark data sets shows that our DBDN outperforms the state of the art in SISR with a moderate number of network parameters.
Wang, Z, Xu, M, Ye, N, Wang, R & Huang, H 1970, 'RF-MVO: Simultaneous 3D Object Localization and Camera Trajectory Recovery Using RFID Devices and a 2D Monocular Camera', 2018 IEEE 38th International Conference on Distributed Computing Systems (ICDCS), 2018 IEEE 38th International Conference on Distributed Computing Systems (ICDCS), IEEE, Vienna, Austria.
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Most of the existing RFID-based localization systems cannot well locate RFID-tagged objects in a 3D space. Limited robot-based RFID solutions require reader antennas to be carried by a robot moving along an already-known trajectory at a constant speed. As the first attempt, this paper presents RFMVO, which fuses battery-free RFID and monocular visual odometry to locate stationary RFID tags in a 3D space and recover an unknown trajectory of reader antennas binding with a 2D monocular camera. The proposed hybrid system exhibits three unique features. Firstly, since the trajectory of a 2D monocular camera can only be recovered up to an unknown scale factor, RF-MVO combines the relative-scale camera trajectory with depth-enabled RF phase to estimate an absolute scale factor and spatially incident angles of an RFID tag. Secondly, we propose a joint optimization algorithm consisting of coarse-to-fine angular refinement, 3D tag localization and parameter nonlinear optimization, to improve real-time performance. Thirdly, RFMVO can determine the effect of relative tag-antenna geometry on the estimation precision, providing optimal tag positions and absolute scale factors. Our experiments show that RF-MVO can achieve 6.23cm tag localization accuracy in a 3D space and 0.0158 absolute scale factor estimation accuracy for camera trajectory recovery.
Xi, Y, Zheng, J, He, X, Jia, W & Li, H 1970, 'Beyond Context: Exploring Semantic Similarity for Tiny Face Detection', 2018 25th IEEE International Conference on Image Processing (ICIP), 2018 25th IEEE International Conference on Image Processing (ICIP), IEEE, Athens, Greece, pp. 1907-1911.
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© 2018 IEEE. Tiny face detection aims to find faces with high degrees of variability in scale, resolution and occlusion in cluttered scenes. Due to the very little information available on tiny faces, it is not sufficient to detect them merely based on the information presented inside the tiny bounding boxes or their context. In this paper, we propose to exploit the semantic similarity among all predicted targets in each image to boost current face detectors. To this end, we present a novel framework to model semantic similarity as pairwise constraints within the metric learning scheme, and then refine our predictions with the semantic similarity by utilizing the graph cut techniques. Experiments conducted on three widely-used benchmark datasets have demonstrated the improvement over the-state-of-the-arts gained by applying this idea.
Yang, T, Ding, C, Ziolkowski, RW & Guo, YJ 1970, 'High Birefringent ENZ Photonic Crystal Fibers', 2018 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD), 2018 International Conference on Numerical Simulation of Optoelectronic Devices (NUSOD), IEEE, Hong Kong, China, pp. 85-86.
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© 2018 IEEE. A novel photonic crystal fiber (PCF) design that has a simple circular air hole configuration is reported that yields a very high birefringence. The enhanced birefringence is achieved by filling a select number of the air holes in its cladding with an epsilon-near-zero (ENZ) material to break the index symmetry of its X- A nd Y-polarization states. Comparisons of initial numerical simulations based on ideal ENZ materials and then those based on realistic ones demonstrate that the high birefringence property is still maintainable with currently available ENZ materials.
Yang, Y, Xu, M, Wu, W, Zhang, R & Peng, Y 1970, '3D Multiview Basketball Players Detection and Localization Based on Probabilistic Occupancy', 2018 Digital Image Computing: Techniques and Applications (DICTA), 2018 Digital Image Computing: Techniques and Applications (DICTA), IEEE, Australia, pp. 267-274.
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© 2018 IEEE. This paper addresses the issue of 3D multiview basketball players detection and localization. Existing methods for this problem typically take background subtraction as input, which limits the accuracy of localization and the performance of further object tracking. Moreover, the performance of background subtraction based methods is heavily impacted by the occlusions in crowded scenes. In this paper, we propose an innovative method which jointly implements deep learning based player detection and occupancy probability based player localization. What's more, a new Bayesian model of the localization algorithms is developed, which uses foreground information from fisheye cameras to setup meaningful initialization values in the first step of iteration, in order to not only eliminate ambiguous detection, but also accelerate computational processes. Experimental results on real basketball game data demonstrate that our methods significantly improve the performance compared with current methods, by eliminating missed and false detection, as well as increasing probabilities of positive results.
Yang, Y, Zhu, H, Zhu, X & Xue, Q 1970, 'Integrated Third-Order Millimeter-Wave On-Chip Bandpass Filter using 0.13-μm SiGe Bi-CMOS Technology', 2018 IEEE/MTT-S International Microwave Symposium - IMS, 2018 IEEE/MTT-S International Microwave Symposium - IMS 2018, IEEE, Philadelphia, PA, pp. 1095-1098.
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© 2018 IEEE. This paper introduces an on-chip third-order bandpass filter (BPF) for millimeter-wave (mm-wave) applications. The proposed BPF is composed of three identical broadside-coupled meander-line resonators (BCMLR) which are jointly connected by three MIM capacitors through aT-shape network. The MIM capacitors are used as J-inverters for the implementation of the third-order BPF in order to achieve the desired multiple transmission poles and zeros across the passband and stopband, correspondingly. To fully understand the operational mechanism of the proposed high-order structure, the resonator and the proposed BPF are analyzed using an LC- equivalent circuit model for further investigation of the distribution of the transmission poles and zeros in terms of the metal inductance and MIM capacitance. To prove the concept, the proposed BPF prototype is implemented in a commercial 0.13-l.lm SiGe (Bi)-CMOS process. According to the results obtained from on-wafer measurement, three transmission poles and three transmission zeros are clearly observed. Noticeably, the proposed BPF exhibits excellent performances including a flat in-band response (less than 1 dB attenuation) from 26.7 GHz to 44.3 GHz with a measured insertion loss of 3.1 dB at the center frequency of 35.5 GHz and stopband attenuation up to 35 dB at 59 GHz. The chip size is 0.016 mm2(0.066 × 0.236 mm-), excluding the GSG pads.
Yao, L, Kusakunniran, W, Wu, Q, Zhang, J & Tang, Z 1970, 'Robust CNN-based Gait Verification and Identification using Skeleton Gait Energy Image', 2018 Digital Image Computing: Techniques and Applications (DICTA), 2018 Digital Image Computing: Techniques and Applications (DICTA), IEEE, Canberra, Australia.
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© 2018 IEEE. As a kind of behavioral biometrie feature, gait has been widely applied for human verification and identification. Approaches to gait recognition can be classified into two categories: model-free approaches and model-based approaches. Model-free approaches are sensitive to appearance changes. For model-based approaches, it is difficult to extract the reliable body models from gait sequences. In this paper, based on the robust skeleton points produced from a two-branch multi-stage CNN network, a novel model-based feature, Skeleton Gait Energy Image (SGEI), has been proposed. Relevant experimental performances indicate that SGEI is more robust to the cloth changes. Another contribution is that two different CNN-based architectures have been separately proposed for gait verification and gait identification. Both these two architectures have been evaluated on the datasets. They have presented satisfying performances and increased the robustness for gait recognition in the unconstrained environments with view variances and cloth variances.
Yu, G, Wang, X, Zha, X, Zhang, JA & Liu, RP 1970, 'An Optimized Round-Robin Scheduling of Speakers for Peers-to-Peers-Based Byzantine Faulty Tolerance', 2018 IEEE Globecom Workshops (GC Wkshps), 2018 IEEE Globecom Workshops (GC Wkshps), IEEE, Abu Dhabi, United Arab Emirates.
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© 2018 IEEE. Blockchain technology has been showing its strong performance on decentralized security when integrating with Internet of Things network. However, the trilemma of scalability-security-decentralization exists in Blockchain-based IoT. Therein the typical round-robin scheduling implemented in the Byzantine Faulty Tolerance (BFT) proposed by Neo's Blockchain has a significant delay when consecutive faulty miners exist. This paper proposes a novel analysis model for evaluating the network performance collapse in general, followed by an optimized round-robin scheduling for the case when the mutual latency difference is not significant enough for ranking. Based on the model, the optimized mechanism is able to increase the block rate for a specific subset of consecutive faulty miners by nearly 50% and provide a linearly positive growth rate of the mitigation with respect to the fail rate of a single miner, which strongly promotes the efficiency of the P2P-based BFT consensus algorithm.
Yu, Z & Chaczko, Z 1970, 'Optimization of IMU Indoor Localization with Wireless Sensors', 2018 IEEE 4th International Conference on Computer and Communications (ICCC), 2018 IEEE 4th International Conference on Computer and Communications (ICCC), IEEE, China, Chengdu.
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Yuan, W, Shi, Q, Wu, N, Guo, Q & Huang, X 1970, 'Gaussian Message Passing Based Passive Localization in the Presence of Receiver Detection Failures', 2018 IEEE 87th Vehicular Technology Conference (VTC Spring), 2018 IEEE 87th Vehicular Technology Conference (VTC Spring), IEEE, Porto, Portugal, pp. 1-5.
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© 2018 IEEE. This paper considers the issue of passive localization based on time of arrival (TOA) measurement in the presence of receiver detection failures. In passive localization, the signal sent from the transmitter is reflected or relayed by «passive» target and then received at several distributed receivers. The target's position can be determined by collecting range mea- surements from all receivers. With a linearized model for range measurements, we build a factor graph model and implement Gaussian message passing algorithm to obtain target location and detect link failures. The Cramer-rao bound (CRB) is also derived to evaluate the performance of proposed algorithm. Simulation results verify the effectiveness of proposed factor graph approach.
Zhang, H, Huang, X & Guo, YJ 1970, 'Low-Complexity Digital Modem Implementation for High-Speed Point-to-Point Wireless Communications', 2018 18th International Symposium on Communications and Information Technologies (ISCIT), 2018 18th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Bangkok, Thailand, pp. 171-175.
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© 2018 IEEE. A low-complexity digital modem is presented in this paper for achieving high-speed and wideband point-To-point (P2P) wireless communications. By combining multiple functionalities into the transmitter and receiver filters, the signal processing complexity in the digital baseband can be significantly reduced. The structures and the implementation using field programmable gate array (FPGA) for the transmitter and receiver filters are described in details. Pre-equalization for reducing the impact of practical channel frequency response can be easily incorporated into the transmitter filter structure. The experimental test results using a 20 Gigabits per second (Gbps) digital modem prototype demonstrate the satisfactory performance with low FPGA resource usage.
Zhang, H, Huang, X & Guo, YJ 1970, 'Low-Complexity Digital Modem Implementation for High-Speed Point-to-Point Wireless Communications', 2018 18TH INTERNATIONAL SYMPOSIUM ON COMMUNICATIONS AND INFORMATION TECHNOLOGIES (ISCIT), 18th International Symposium on Communications and Information Technologies (ISCIT), IEEE, Bangkok, THAILAND, pp. 16-21.
Zhang, J, Wu, Q, Shen, C, Zhang, J, Lu, J & van den Hengel, A 1970, 'Goal-Oriented Visual Question Generation via Intermediate Rewards', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), European Conference on Computer Vision, Springer International Publishing, Munich, Germany, pp. 189-204.
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© 2018, Springer Nature Switzerland AG. Despite significant progress in a variety of vision-and-language problems, developing a method capable of asking intelligent, goal-oriented questions about images is proven to be an inscrutable challenge. Towards this end, we propose a Deep Reinforcement Learning framework based on three new intermediate rewards, namely goal-achieved, progressive and informativeness that encourage the generation of succinct questions, which in turn uncover valuable information towards the overall goal. By directly optimizing for questions that work quickly towards fulfilling the overall goal, we avoid the tendency of existing methods to generate long series of inane queries that add little value. We evaluate our model on the GuessWhat?! dataset and show that the resulting questions can help a standard ‘Guesser’ identify a specific object in an image at a much higher success rate.
Zhang, P, Wu, Q, Xu, J & Zhang, J 1970, 'Long-Term Person Re-identification Using True Motion from Videos', 2018 IEEE Winter Conference on Applications of Computer Vision (WACV), 2018 IEEE Winter Conference on Applications of Computer Vision (WACV), IEEE, Lake Tahoe, NV, USA, pp. 494-502.
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© 2018 IEEE. Most person re-identification approaches and benchmarks assume that pedestrians go across the surveillance network without significant appearance changes in a brief period, which explicitly restricts person re-identification to a short-term event and incurs inter-sample similarity measurement by appearance matching. However, pedestrians are likely to reappear in the surveillance network after a long-time interval (long-term) and change their wearing in many real-world scenarios. These scenarios inevitably cause appearances between subjects more ambiguous and indistinguishable. In this paper we consider these scenarios and propose a unified feature representation based on true motion cues from videos named FIne moTion encoDing (FITD). Our hypothesis is that people keep constant motion patterns under non-distraction walking condition. Therefore, the motion characteristics are more reliable than static appearance feature to describe a walking person. Particularly, we extract motion patterns hierarchically by encoding trajectory-aligned descriptors with Fisher vectors in a spatial-aligned pyramid. To verify benefits of the proposed FITD, we collect a new dataset typically for the long-term situations. Extensive experiments demonstrate the merits of our FITD especially for the long-term scenarios.
Zhang, T, Gong, C, Jia, W, Song, X, Sun, J & Wu, X 1970, 'Supervised Image Classification with Self-Paced Regularization', 2018 IEEE International Conference on Data Mining Workshops (ICDMW), 2018 IEEE International Conference on Data Mining Workshops (ICDMW), IEEE, Singapore, Singapore, pp. 411-414.
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© 2018 IEEE. In this paper, we present a new scheme for image classification that is robust to samples noises. The proposed scheme depicts a novel sparse classification model with self-paced learning mechanism. First, inspired by the outstanding performance of curriculum learning, we integrate the idea of self-paced learning into supervised class-specific dictionary learning to select appropriate training samples. Secondly, we design a novel sparse representation model associated with self-paced learning regularization, which employs locally linear reconstruction to improve the accuracy of the classifier and exploit the manifold structure of data. By using the designed model, a classification scheme integrating self-paced learning is proposed to exploit more discriminative image information. The experimental results on two typical datasets indicate that our constructed model achieves the competitive performance when compared with the state-of-the-art methods.
Zhang, Z, Wu, Q, Wang, Y & Chen, F 1970, 'Fine-Grained and Semantic-Guided Visual Attention for Image Captioning', 2018 IEEE Winter Conference on Applications of Computer Vision (WACV), 2018 IEEE Winter Conference on Applications of Computer Vision (WACV), IEEE, Lake Tahoe, NV, USA, pp. 1709-1717.
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© 2018 IEEE. Soft-attention is regarded as one of the representative methods for image captioning. Based on the end-to-end CNN-LSTM framework, it tries to link the relevant visual information on the image with the semantic representation in the text (i.e. captioning) for the first time. In recent years, there are several state-of-the-art methods published, which are motivated by this approach and include more elegant fine-tune operation. However, due to the constraints of CNN architecture, the given image is only segmented to fixed-resolution grid at a coarse level. The overall visual feature created for each grid cell indiscriminately fuses all inside objects and/or their portions. There is no semantic link among grid cells, although an object may be segmented into different grid cells. In addition, the large-area stuff (e.g. sky and beach) cannot be represented in the current methods. To tackle the problems above, this paper proposes a new model based on the FCN-LSTM framework which can segment the input image into a fine-grained grid. Moreover, the visual feature representing each grid cell is contributed only by the principal object or its portion in the corresponding cell. By adopting the pixel-wise labels (i.e. semantic segmentation), the visual representations of different grid cells are correlated to each other. In this way, a mechanism of fine-grained and semantic-guided visual attention is created, which can better link the relevant visual information with each semantic meaning inside the text through LSTM. Without using the elegant fine-tune, the comprehensive experiments show promising performance consistently across different evaluation metrics.
Zhang, Z, Wu, Q, Wang, Y & Chen, F 1970, 'Size-Invariant Attention Accuracy Metric for Image Captioning with High-Resolution Residual Attention', 2018 Digital Image Computing: Techniques and Applications (DICTA), 2018 Digital Image Computing: Techniques and Applications (DICTA), IEEE, Canberra, Australia, pp. 1-8.
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© 2018 IEEE. Spatial visual attention mechanisms have achieved significant performance improvements for image captioning. To quantitatively evaluate the performances of attention mechanisms, the 'attention correctness' metric has been proposed to calculate the sum of attention weights generated for ground truth regions. However, this metric cannot consistently measure the attention accuracy among the element regions with large size variance. Moreover, its evaluations are inconsistent with captioning performances across different fine-grained attention resolutions. To address these problems, this paper proposes a size-invariant evaluation metric by normalizing the 'attention correctness' metric with the size percentage of the attended region. To demonstrate the efficiency of our size-invariant metric, this paper further proposes a high-resolution residual attention model that uses RefineNet as the Fully Convolutional Network (FCN) encoder. By using the COCO-Stuff dataset, we can achieve pixel-level evaluations on both object and 'stuff' regions. We use our metric to evaluate the proposed attention model across four high fine-grained resolutions (i.e., 27×27, 40×40, 60×60, 80×80). The results demonstrate that, compared with the 'attention correctness' metric, our size-invariant metric is more consistent with the captioning performances and is more efficient for evaluating the attention accuracy.
Zhu, H & Abbosh, AM 1970, 'Wideband tunable reflection-type phase shifter using high-directivity directional coupler', 2018 Australian Microwave Symposium (AMS), 2018 Australian Microwave Symposium (AMS), IEEE, Brisbane, QLD, Australia, pp. 49-50.
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© 2018 IEEE. A wideband tunable phase shifter that uses the concept of reflection-type phase shifter is proposed. The device is based on a tunable high-directivity directional coupler. The coupler uses two pairs of interconnected coupled-lines with suitable coplanar-waveguide transmission lines embedded within the ground plane. The tuning is realized by using two varactors and two inductors connected to two terminals of the coupler. Full-wave simulation is performed using co-simulation within ADS momentum using accurate SPICE model of the tuning elements. Moreover, a prototype is fabricated and tested. The tested results reveal that the proposed design can achieve wide operating bandwidth (105% fractional bandwidth) with 40° tuning phase.
Zhu, H & Guo, YJ 1970, 'Modified Wideband Tandem Couplers with Arbitrary Coupling Coefficient and its Implementation in Beam-Forming Networks', 2018 Asia-Pacific Microwave Conference (APMC), 2018 Asia-Pacific Microwave Conference (APMC), IEEE, Kyoto, Japan, pp. 542-544.
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© 2018 IEICE This paper presents a wideband quadrature coupler using a modified Tandem structure with two stages of cascaded coupled-lines. The proposed design is built in the stripline configuration, which can achieve wide operating bandwidth and excellent matching as well as high isolation across the whole band range. The proposed design with coupling coefficient of 3-dB and 1.77-dB is applied in the design of a wideband beam-forming network for wideband applications. Experimental result has been carried out, verifying that the design approach is useful for wideband applications.
Zhu, HL, Cao, YX, Ding, C, Wei, G & Jay Guo, Y 1970, 'Main Beam Manipulation of Patch Antenna Using Non-uniform Meta-surface', ISAP 2018 - 2018 International Symposium on Antennas and Propagation, International Symposium on Antennas and Propagation, IEEE, Busan, South Korea.
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A method to manipulate the main beam of patch antenna using non-uniform meta-surface (MS) is proposed in this paper. The proposed antenna is composed of a non-uniform MS placed directly atop of a patch antenna with an area of 100∗100 mm2 (0.82 λ 0∗ 0.82 λ 0), making it compact and low profile. After adding the MS to the patch antenna, the main-beam direction can be tilted by an angle of 30° from the boresight direction. The proposed antenna is studied and designed to operate around 2.45 GHz. Simulated results show that the antenna has an operating bandwidth from 2.372.51GHz and peak realized gain of 7.3dBi.