#### Electrical and Electronics Engineering publications abstract of: 07-2017 sorted by title, page: 13

» Realization of Low Scattering for a High-Gain Fabry–Perot Antenna Using Coding Metasurface
 Abstract:We present a novel method to design a conventional Fabry–Perot (F-P) antenna but with low scattering. Combining a coding metasurface and an F-P antenna together could effectively reduce the scattering and keep high gain simultaneously. The coding element consists of two layers of square metallic patches printed on both sides of a dielectric substrate. The bottom metallic patch helps form a partially reflecting surface (PRS) for the F-P antenna, while the upper metallic patch is utilized to construct the coding metasurface with an optimized coding sequence, aiming to reduce the scattering of the F-P antenna by redirecting electromagnetic energies in all directions. Based on the specially designed coding metasurface, a good scattering reduction without degrading the radiation performance of the F-P antenna is achieved. Both simulated and experimental results demonstrate the excellent performance of the proposed antenna, with a peak measured gain of 19.8 dBi and a significant scattering reduction in the frequency range of 8–12 GHz. Autors: Lei Zhang;Xiang Wan;Shuo Liu;Jia Yuan Yin;Qian Zhang;Hao Tian Wu;Tie Jun Cui; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3374 - 3383 Publisher: IEEE
» Reasoning About Job Completion Time in Vehicular Clouds
 Abstract:In order to enhance dependability and availability, it is common practice in conventional clouds to assign two servers to each job. In this paper, we investigate the effect of such a redundancy-based job assignment strategy on job completion time in vehicular clouds. We offer a heuristic analysis of the expected job completion time under this strategy. A comprehensive set of simulations confirmed the accuracy of our analytical predictions. Autors: Ryan Florin;Puya Ghazizadeh;Aida Ghazi Zadeh;Samy El-Tawab;Stephan Olariu; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Jul 2017, volume: 18, issue:7, pages: 1762 - 1771 Publisher: IEEE
» Receding Horizon Control of Wind Power to Provide Frequency Regulation
 Abstract:With the increased penetration of wind generation in power systems, there is a rising interest in the provision of frequency regulation by wind turbines in order to relieve the burden on remaining conventional generation units. As a first step, the possible contribution of wind power to frequency regulation by optimally anticipating load imbalances in the power system is investigated. This ability is studied by implementing a receding horizon control which takes future load and wind variations into account. In this way, the available energy reserves of the wind turbine over a certain time horizon are optimally exploited to damp frequency oscillations while keeping the energy losses within defined limits. Results indicate that the receding horizon controller will mainly damp overfrequencies as its upward regulation capability is restricted to the available kinetic energy in the turbines. Moreover, it is shown that load forecast errors only slightly influence the results as the controller iteratively determines the optimal trajectory. Even if no load forecast is available, the proposed controller is still capable of damping frequency variations resulting from the simulated load profile by 25%, while keeping the energy yield above 97% compared to optimal power point tracking. Autors: Pieter Tielens;Dirk Van Hertem; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2663 - 2672 Publisher: IEEE
» Recoverable Energy of Radiating Structures
 Abstract:In this paper, the maximum “recoverable” energy of a radiator is determined. This energy is defined as the maximum energy that can be recovered from the electromagnetic field distribution in entire space generated by the radiator up to the time point considered. The calculation procedure is based on minimizing the future radiated energy. It is shown that the concept of recoverable energy has no problems with so-called “negative energies,” or with any dependence on coordinate system, issues that compromise many definitions found in literature of the concept of “stored” energy for a radiator. The question can be raised whether “recoverable” energy can be identified with stored energy for a radiator. Autors: Guy A. E. Vandenbosch; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3575 - 3588 Publisher: IEEE
» Recursive Identification of Hammerstein Systems: Convergence Rate and Asymptotic Normality
 Abstract:In this work, recursive identification algorithms are developed for Hammerstein systems under the conditions considerably weaker than those in the existing literature. For example, orders of linear subsystems may be unknown and no specific conditions are imposed on their moving average part. The recursive algorithms for estimating both linear and nonlinear parts are based on stochastic approximation and kernel functions. Almost sure convergence and strong convergence rates are derived for all estimates. In addition, the asymptotic normality of the estimates for the nonlinear part is also established. The nonlinearity considered in the paper is more general than those discussed in the previous papers. A numerical example verifies the theoretical analysis with simulation results. Autors: Biqiang Mu;Han-Fu Chen;Le Yi Wang;George Yin;Wei Xing Zheng; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3277 - 3292 Publisher: IEEE
» Reducing Costs of LIPA Handover Through Bearer Reservation With Preemption
 Abstract:In long-term evolution-advanced (LTE-Advanced) networks, a local IP access (LIPA) mechanism allows packets to be routed locally between home eNodeBs (HeNBs) without being passed back to the core network. When a user equipment (UE) communicates with another UE through LIPA and hands over to an eNodeB (eNB), lots of unnecessary message exchanges are required to release and reestablish bearers between HeNB and eNB. To reduce the handover costs, we propose a bearer reservation with preemption (BRP) scheme to reserve bearers instead of releasing bearers for handover sessions. To ensure that normal sessions are not affected by the reserved bearers, the reserved bearers are preemptible by normal sessions. Results of performance evaluation show that, in most cases, more than of message exchanges can be reduced by the BRP scheme. Autors: Chih-Hao Lai;Hui-Ling Chang;Meng-Hsun Tsai;Chia-Ying Lin; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Jul 2017, volume: 66, issue:7, pages: 6428 - 6438 Publisher: IEEE
» Reduction of Sufficient Conditions for Optimal Control Problems With Subgroup Symmetry
 Abstract:In this paper, we apply symmetry reduction techniques from geometric mechanics to sufficient conditions for local optimality in optimal control problems. After reinterpreting some previous results for left-invariant problems on Lie groups, we focus on optimal control problems with subgroup symmetry. For these problems, the necessary conditions for optimality can be simplified by exploiting symmetries so as to reduce the number of variables needed to describe trajectories of the system. We show that sufficient conditions for optimality, based on the non-existence of conjugate points, can be simplified in an analogous way to the necessary conditions. We demonstrate these simplifications by analyzing an optimal control problem that models a spinning top in a gravitational field, and we give particular attention to the example of an axisymmetric sleeping top. The results we derive in this paper allow us to determine which trajectories of a sleeping top are locally optimal solutions of the optimal control problem, which is a new result that has not appeared in previous literature. Autors: Andy Borum;Timothy Bretl; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3209 - 3224 Publisher: IEEE
» Redundant Local-Loop Insertion for Unidirectional Routing
 Abstract:As the semiconductor manufacturing technology continues to scale down to sub-10 nm, unidirectional layout style has become the mainstream for lower metal layers with tight pitches. Conventional redundant via (RV) insertion for yield improvement has become obsolete because unidirectional routing patterns forbid off-track routing, i.e., wire bending, for the metal coverage of RVs. To enhance the yield, redundant local-loop insertion (RLLI) is a new way of inserting RVs due to its compatibility with the unidirectional layout style. This paper proposes the first global optimization engine for RLLI considering advanced manufacturing constraints. Our key contributions include bounded timing impact analysis and evaluation for the local-loop structure, net-based local-loop candidate generation and pruning, an integer linear programming (ILP) formulation and scalable iterative relaxation/linear programming solving (IRLS) with incremental search scheme. Experimental results demonstrate that with bounded timing impact (within 1%), the ILP formulation obtains highest insertion rate while the IRLS with incremental search scheme achieves scalable solutions with competitive solution qualities. Autors: Xiaoqing Xu;Yibo Lin;Meng Li;Jiaojiao Ou;Brian Cline;David Z. Pan; Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Publication date: Jul 2017, volume: 36, issue:7, pages: 1113 - 1125 Publisher: IEEE
» Reed–Muller Codes Achieve Capacity on Erasure Channels
 Abstract:We introduce a new approach to proving that a sequence of deterministic linear codes achieves capacity on an erasure channel under maximum a posteriori decoding. Rather than relying on the precise structure of the codes, our method exploits code symmetry. In particular, the technique applies to any sequence of linear codes where the blocklengths are strictly increasing, the code rates converge, and the permutation group of each code is doubly transitive. In other words, we show that symmetry alone implies near-optimal performance. An important consequence of this result is that a sequence of Reed–Muller codes with increasing blocklength and converging rate achieves capacity. This possibility has been suggested previously in the literature but it has only been proven for cases where the limiting code rate is 0 or 1. Moreover, these results extend naturally to all affine-invariant codes and, thus, to extended primitive narrow-sense BCH codes. This also resolves, in the affirmative, the existence question for capacity-achieving sequences of binary cyclic codes. The primary tools used in the proof are the sharp threshold property for symmetric monotone Boolean functions and the area theorem for extrinsic information transfer functions. Autors: Shrinivas Kudekar;Santhosh Kumar;Marco Mondelli;Henry D. Pfister;Eren Şaşoǧlu;Rüdiger L. Urbanke; Appeared in: IEEE Transactions on Information Theory Publication date: Jul 2017, volume: 63, issue:7, pages: 4298 - 4316 Publisher: IEEE
» Reference Injected Phase-Locked Loops (PLL-RIs)
 Abstract:In this paper, we use synchronization to reduce phase-locked loop (PLL) phase noise and improve its locking behavior with an attenuated reference signal injection (RI) into a voltage-controlled CMOS delay-line ring-type oscillator. The transient and steady-state behavior of the PLL-RI are described by a nonlinear differential equation, which is further studied by the phase-plane method. The nonlinear equation is linearized for the small-signal condition and the s-domain noise transfer functions and noise bandwidths for different noise sources are derived. The effect of the loop parameters and the injection strength on the output phase noise, loop settling time, and lock in range is analyzed. Finally, the analysis is verified by the SPICE simulation and measurement results from an 1-GHz PLL-RI with 130-nm standard RF CMOS technology. Simulation and measurement results show phase noise reduction and improved settling behavior of a PLL-RI compared with a conventional PLL. Autors: Feiran Lei;Marvin H. White; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Jul 2017, volume: 64, issue:7, pages: 1651 - 1660 Publisher: IEEE
» Reflection Reduction Through Modal Filtering for Integrated Antenna Measurements Above 100 GHz
 Abstract:Feeding integrated antennas during a measurement requires special feeding structures. Due to the small antenna dimensions, these feeding structures are often much bigger than the antenna under test (AUT) itself and with chip sizes of around 1 mm2, the achievable separation between antenna and feed is limited. Wafer probes have to be used to feed the AUT during passive antenna measurements and present a large reflective surface in close proximity to the AUT. Reflections from the wafer probe cause interference on the measurement surface and distort the results. The same is true for active antenna measurements, where bondwires and the package can have a significant effect on the radiated fields. The fragility and size of the components do not allow to reduce reflections with absorbers, which is why modal filtering was used in this paper to mitigate undesired reflections and improve the measurement result through postprocessing. Two issues that limit the performance of the algorithm are discussed, namely, phase center inaccuracies of the AUT and a limited measurement surface. It is shown that modal filtering is applicable to integrated antenna measurements at frequencies over 100 GHz and that a significant improvement in the measured radiation pattern can be achieved. Furthermore, it is shown that the postprocessed results make it possible to measure the directivity of integrated antennas, despite strong probe reflections. Autors: Linus Boehm;Alexander Foerstner;Martin Hitzler;Christian Waldschmidt; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3712 - 3720 Publisher: IEEE
» Regeneration of Sooty Surface Using Nanosecond Pulsed Dielectric Barrier Discharge
 Abstract:In this paper, the regeneration of sooty surface by using nanosecond pulsed surface dielectric barrier discharge type reactor is investigated experimentally. The goal is to characterize the regeneration process as a function of the applied voltage magnitude and pulse polarity. The reactor is composed of two electrodes separated by a dielectric and are arranged asymmetrically. The power supply system provides high voltage pulses with the following characteristics: voltage up to ±10 kV; rise and decay time less than 50 ns; and a frequency of 2 kHz. The main results show that the regeneration performance increases with the applied voltage magnitude and the duration of treatment. Furthermore, depending on the polarity and the magnitude of the applied voltage pulse, the cleaned surface area can be either more uniform along the active electrode (negative pulses) or extended on the dielectric surface (positive pulses). The regeneration mechanism remains not very well understood, but it seems that the soot particle size is reduced mainly due to the interaction with ozone molecules and oxygen radicals generated by the discharge. Autors: Noureddine Zouzou;Arthur Claude Aba'a Ndong;Eric Moreau; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3982 - 3988 Publisher: IEEE
» Regularized Deep Belief Network for Image Attribute Detection
 Abstract:In general, an image attribute is a human-nameable visual property that has a semantic connotation. Appropriate modeling of the intrinsic contextual correlations among attributes plays a fundamental role in attribute detection. In this paper, we consider image attribute detection from the perspective of regularized deep learning. In particular, we propose a regularized deep belief network (rDBN) to perform the image attribute detection task, which is composed of two parts: 1) a detection DBN (dDBN) that models the joint distribution of images and their corresponding attributes, which acts as an attribute detector and 2) a contextual restricted Boltzmann machine that explicitly models the correlations among attributes acting as a regularizer that restraints the output detection result given by the dDBN to meet the contextual prior of attributes. Furthermore, we propose an efficient fine-tuning scheme that can further optimize the performance of the dDBN by backpropagation. Experimental results show that the proposed rDBN obtains improvements over the state-of-the-art methods for attribute detection on the benchmark data sets. Autors: Fei Wu;Zhuhao Wang;Weiming Lu;Xi Li;Yi Yang;Jiebo Luo;Yueting Zhuang; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Jul 2017, volume: 27, issue:7, pages: 1464 - 1477 Publisher: IEEE
» Regulating the Output Voltage of the Resonant Switched-Capacitor Converters Below Their Resonant Frequencies
 Abstract:Resonant switched-capacitor converters have widely been used recently to increase conversion power density. The most significant drawback of these converters is voltage regulation problem when their input voltages vary in wide ranges. Here, a basic double voltage-ratio resonant switched-capacitor converter (SCC) is analyzed and simulated below its resonant frequency under the different operation modes to overcome this problem. The converter different parameters are calculated under both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) conditions. The advantages and drawbacks of these operation modes are compared and the closed-loop control of the converter is also investigated based on the extended describing function approach. The given analyses demonstrate that the output voltage can be well-regulated under the CCM1 and DCM2 operation modes even when wide input voltage and load variations are applied. Besides, the DCM1 operation mode must be avoided when output voltage regulation is important. Based on the given analytical and experimental results, switching frequency varies in a reasonable range to regulate the output voltage. Also, faster transient responses, smaller output capacitor, and smaller resonant tank components can be used below the resonant frequency, as compared to the above resonant frequency, but lower efficiency value is achieved. The given approach has been extended to the other resonant SCCs as well. Autors: Reza Beiranvand; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5236 - 5249 Publisher: IEEE
» Reliability Enhancement of Low-Power Sequential Circuits Using Reconfigurable Pulsed Latches
 Abstract:Pulsed latches are gaining increased visibility in low-power ASIC designs. They provide an alternative sequential element with high performance and low area and power consumption, taking advantage of both latch and flip-flop features. While the circuit reliability and robustness against different process, voltage, and temperature variations are considered as critical issues with current technologies, no significant reliability study was proposed for pulsed latch circuits. In this paper, we present a study on the effect of different PVT variations on the behavior of pulsed latches, considering the effect on both the pulser and the latch. In addition, two novel design approaches are presented to enhance the reliability of pulsed latch circuits, while keeping their main advantages of high performance, low power, and small area. Experiments performed using Synopsys 28nm PDK demonstrate the ability of the proposed approaches to keep the same reliability level at different supply voltages and temperatures in the presence of process variations, with a very small area overhead of around 3%. The two proposed designs have negligible power overhead when running at nominal supply voltage, and they have higher yield per unit power when compared with the traditional design at different voltages and temperatures. Autors: Wael M. Elsharkasy;Amin Khajeh;Ahmed M. Eltawil;Fadi J. Kurdahi; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Jul 2017, volume: 64, issue:7, pages: 1803 - 1814 Publisher: IEEE
» Reliable Relay: Autonomous Social D2D Paradigm for 5G LoS Communications
 Abstract:Next generation 5G networks contemplate to exploit millimeter Wave (mmWave) for a massive increase in data rates but its inherent characteristic of line-of-sight (LoS) brings up the challenge of directional synchronization of transmitters and receivers. In this letter, we propose a fusion of social Internet-of-Things and device-to-device (D2D) communications, shaping social D2D to tackle mmWave LoS challenge using an independent “reliable relay” scheme. We introduce distributed social network of devices and propose social-communication graph formation and autonomous trustworthy relay procedure. Utilizing reliable relay, a non-LoS device can communicate to 5G networks without compromising the contents privacy. Our analysis demonstrates that agile reliable relay substantially improves the capacity gain and data rate and can be an integral part of existing relay selection schemes. NS3-based simulations validate the proliferation in throughput with minimum additional delays. Autors: Farooque Hassan Kumbhar;Navrati Saxena;Abhishek Roy; Appeared in: IEEE Communications Letters Publication date: Jul 2017, volume: 21, issue:7, pages: 1593 - 1596 Publisher: IEEE
» Reliable Renewable Generation and Transmission Expansion Planning: Co-Optimizing System's Resources for Meeting Renewable Targets
 Abstract:The current renewable-driven generation expansion wave, pushed by high renewable targets, is not accompanied by the same movement in the transmission expansion planning (TEP) side. In this context, new techniques are needed to balance the cost of relying in expensive reserve resources and the cost of building new lines to ensure least-cost reserve deliverability and foster new renewable projects. The situation is worsened in the presence of contingencies, where the interaction between the optimal reserve siting and deployment, the amount of renewable curtailment, the construction of new lines, and the selection of candidate renewable sites to be developed became even more complex. This paper presents a two-stage min-max-min model for co-optimizing the expansion of the transmission system and renewable generation capacity to meet renewable targets under high security standards and renewable uncertainty. In order to account for realistic reserve needs and its interaction with the expansion plan, correlations between renewables injection as well as generation and transmission (GT) outages are accounted for in a robust fashion. In order to ensure security within a flexible framework, the concept of compound GT security criteria is presented. Three case studies are proposed to illustrate the applicability of the proposed model. A case study with realistic data from the Chilean system is presented and solutions obtained with different levels of security are tested against a set of 10 000 simulated scenarios of renewable injections and system component outages. Autors: Alexandre Moreira;David Pozo;Alexandre Street;Enzo Sauma; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 3246 - 3257 Publisher: IEEE
» Remaining Useful Life Prediction Based on a General Expression of Stochastic Process Models
 Abstract:In remaining useful life (RUL) prediction, stochastic process models are widely used to describe the degradation processes of systems. For age-dependent stochastic process models, the RUL probability density function (PDF) can be calculated using a closed-form solution. For state-dependent models, however, it is difficult to calculate such a closed-form solution. Therefore, the RUL is always approximately estimated using a sequential Monte Carlo-based method, but this method has some limitations. First, it only provides a numerical approximation result whose accuracy highly relies on the quality and quantity of the simulated degradation trajectories. Second, the time interval is unable to be adjusted during the state transition process, resulting in too few discrete probability densities in the result near the end-of-life. This paper describes the degradation processes using a general expression of age- and state-dependent models. The analytical solution of the RUL PDF is derived from the general expression. After that, a new RUL prediction method is proposed. In this method, a series of degradation trajectories are generated through degradation process simulation. The RUL PDF is estimated by inputting the state values of the degradation trajectories into the analytical solution. The validity of the proposed method is verified using fatigue-crack-growth data. Autors: Naipeng Li;Yaguo Lei;Liang Guo;Tao Yan;Jing Lin; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5709 - 5718 Publisher: IEEE
» Remote Handling Refurbishment Process for the European IFMIF Target Assembly: Concept Design, Simulation and Validation in Virtual Environment
 Abstract:The remote handling (RH) maintenance of components of International Fusion Materials Irradiation Facility (IFMIF) is one of the most challenging activities to be performed to guarantee the required high level of IFMIF plant availability. Among these components, the maintenance of the target assembly (TA) system appears to be critical, because it is located in the most severe region of neutron irradiation. The present European TA design is based on the so-called replaceable backplate (BP) bayonet concept. It was developed with the objective to reduce the waste material and to simplify the procedures for the target and BP replacement, thus reducing the intervention time for their substitution. The RH maintenance activity for the TA comprises a number of in situ refurbishment tasks, such as the removal of the BP, cleaning of surfaces from lithium solid deposition, inspection of the target body, installation of a new BP, and testing of the assembled system. However, there is also the possibility to replace the entire TA and to perform these refurbishment tasks offline in a dedicated hot cell. To accomplish all the refurbishment operations for the TA within the expected time for maintenance, the annual preventive maintenance period for IFMIF has been fixed in 20 days; several 3-D kinematic simulations in virtual reality environment and experimental activities aimed at developing and validating the implemented maintenance procedures for this component were carried out, in collaboration with the IDEAinVR Laboratory of CREATE/University of Naples Federico II, at the research center at ENEA Brasimone, Italy. The in situ refurbishment processes and the target replacement were simulated and tested and the feasibility of each maintenance operation was proved. In this paper, a description of the simulations and the validation activities carried out together with the main outcomes obtained are given. Autors: G. Miccichè;L. Lorenzelli;F. Frascati;G. Di Gironimo;R. Mozzillo; Appeared in: IEEE Transactions on Plasma Science Publication date: Jul 2017, volume: 45, issue:7, pages: 1824 - 1830 Publisher: IEEE
» Representation and Factorization of Discrete-Time Rational All-Pass Functions
 Abstract:In this paper, we obtain a general characterization of discrete-time all-pass rational matrix functions from state-space representations. We establish a general characterization of the solutions of LMI's and Riccati equations. Finally, we derive a complete factorization theory of all-pass functions. Our results are obtained in the most general setting, without introducing any ad hoc assumption and can be applied to a variety of problems such as the discrete-time counterpart of the model reduction problems solved by Glover in continuous-time. Autors: Augusto Ferrante;Giorgio Picci; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3262 - 3276 Publisher: IEEE
» Research of Single-Event Burnout in Floating Field Ring Termination of Power MOSFETs
 Abstract:This paper presents the 2-D numerical simulation results of the single-event burnout (SEB) in the floating field ring (FFR) termination of a power MOSFET for the first time. We investigate the SEB triggering mechanism and SEB performance based on a 140-V typical FFR termination, and find that the structure is sensitive to SEB because of a sharp temperature rise appearing at the p+ base/n-drift junction. A 140-V hardened FFR termination (an n-type buffer layer is added between the epitaxial layer and substrate layer) is also studied in this paper that can demonstrate much better SEB performance without sacrificing the basic characteristics compared to the standard one. In addition, the hardening mechanism is explained, and the performances of the hardened structures with different buffer layer thickness are discussed. As a result, the safe operating area can reach the value of the breakdown voltage when the thickness achieves or exceeds . Autors: Cheng-Hao Yu;Ying Wang;Jun Liu;Ling-Ling Sun; Appeared in: IEEE Transactions on Electron Devices Publication date: Jul 2017, volume: 64, issue:7, pages: 2906 - 2911 Publisher: IEEE
» Resilience Enhancement With Sequentially Proactive Operation Strategies
 Abstract:Extreme weather events, many of which are climate change related, are occurring with increasing frequency and intensity and causing catastrophic outages, reminding the need to enhance the resilience of power systems. This paper proposes a proactive operation strategy to enhance system resilience during an unfolding extreme event. The uncertain sequential transition of system states driven by the evolution of extreme events is modeled as a Markov process. At each decision epoch, the system topology is used to construct a Markov state. Transition probabilities are evaluated according to failure rates caused by extreme events. For each state, a recursive value function, including a current cost and a future cost, is established with operation constraints and intertemporal constraints. An optimal strategy is established by optimizing the recursive model, which is transformed into a mixed integer linear programming by using the linear scalarization method, with the probability of each state as the weight of each objective. The IEEE 30-bus system, the IEEE 118-bus system, and a realistic provincial power grid are used to validate the proposed method. The results demonstrate that the proposed proactive operation strategies can reduce the loss of load due to the development of extreme events. Autors: Chong Wang;Yunhe Hou;Feng Qiu;Shunbo Lei;Kai Liu; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2847 - 2857 Publisher: IEEE
» Resilience of Energy Infrastructure and Services: Modeling, Data Analytics, and Metrics
 Abstract:Large-scale power failures induced by severe weather have become frequent and damaging in recent years, causing millions of people to be without electricity service for days. Although the power industry has been battling weather-induced failures for years, it is largely unknown how resilient the energy infrastructure and services really are to severe weather disruptions. What fundamental issues govern the resilience? Can advanced approaches such as modeling and data analytics help industry to go beyond empirical methods? This paper discusses the research to date and open issues related to these questions. The focus is on identifying fundamental challenges and advanced approaches for quantifying resilience. In particular, the first aspect of this problem is how to model large-scale failures, recoveries, and impacts, involving the infrastructure, service providers, customers, and weather. The second aspect is how to identify generic vulnerability in the infrastructure and services through large-scale data analytics. The third aspect is to understand what resilience metrics are needed and how to develop them. Autors: Chuanyi Ji;Yun Wei;H. Vincent Poor; Appeared in: Proceedings of the IEEE Publication date: Jul 2017, volume: 105, issue:7, pages: 1354 - 1366 Publisher: IEEE
» Resilience-Oriented Pre-Hurricane Resource Allocation in Distribution Systems Considering Electric Buses
 Abstract:Proactive preparedness to cope with extreme weather events is significantly helpful in reducing the restoration cost and enhancing the resilience of distribution systems. This paper is focused on the resource allocation problem in distribution systems ahead of a coming hurricane. Generation resources such as diesel oil and batteries are considered for allocation, which can be used to serve outage critical load in the post-hurricane restoration. Electric buses are also considered as a kind of resource. Considering the uncertainties of system faults, the allocation problem is formulated into a mixed-integer stochastic nonlinear program. A heuristic method is then proposed, which obtains the allocation plan by solving a mixed-integer linear program. Numerical simulations are performed on the IEEE 123-node feeder system under several scenarios to demonstrate the effectiveness of the proposed method. The impacts of resources transportation cost, initial distribution of electric buses, and hurricane severity on the allocation plan are discussed. Autors: Haixiang Gao;Ying Chen;Shengwei Mei;Shaowei Huang;Yin Xu; Appeared in: Proceedings of the IEEE Publication date: Jul 2017, volume: 105, issue:7, pages: 1214 - 1233 Publisher: IEEE
» Resistive Coupling-Based Waveform Relaxation Algorithm for Analysis of Interconnect Circuits
 Abstract:A parallel waveform relaxation (WR) algorithm is presented for transient analysis of large distributed interconnect networks. The proposed algorithm partitions interconnect circuits using a Norton interface derived from positive and negative resistors. A theoretical framework is provided to study the convergence properties of the proposed algorithm. From this discussion, a procedure to select the relaxation resistances is described which reduces the number of iterations for the WR algorithm to converge. Numerical examples illustrate the parallelizability and good scaling of the proposed method with respect to the size of the network and the number of central processing units. Autors: Tarik Menkad;Anestis Dounavis; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Jul 2017, volume: 64, issue:7, pages: 1877 - 1890 Publisher: IEEE
» Resistive Sensor Linearity Improvement Based on Change-Ratio-Decreasing and Change-Ratio-Increasing Subunits
 Abstract:To increase the linearity of the resistive sensor, a combined system composed of the change-ratio-decreasing subunit (CRDSU) and the change-ratio-increasing subunit (CRISU) is designed. In the CRDSU/CRISU, the change ratio of the output decreases/increases with the increase of the input. CRDSU and CRISU are used as the neighboring arms of the electrical bridge to convert the measured quantity to the output voltage. The combined system for the displacement sensor based on the piezoresistive effect of conductive polymer composite is developed as an example. The piezoresistive curve of the composite has a transition deformation. If the composite deformation is more/less than the transition deformation, the change ratio of the resistance decreases/increases with the increase of the displacement. To construct the combined system in which the varying tendencies for the change ratios of the resistances for CRDSU and CRISU are opposite, the initial deformations are applied on the subunits which are placed on the opposite sides of the measured workpiece. The experimental results verify the feasibility of using the combined system to improve the linearity. Autors: Luheng Wang; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Jul 2017, volume: 66, issue:7, pages: 1831 - 1836 Publisher: IEEE
» Resolution-Based Content Discovery in Network of Caches: Is the Control Traffic an Issue?
 Abstract:As networking attempts to cleanly separate the control plane and forwarding plane abstractions, it also defines a clear interface between these two layers. An underlying network state is represented as a view to act upon in the control plane. We are interested in studying some fundamental properties of this interface, both in a general framework, and in the specific case of content routing. We try to evaluate the traffic between the two planes based on allowing a minimum level of acceptable distortion in the network state representation in the control plane. We apply our framework to content distribution, and see how we can compute the overhead of maintaining the location of content in the control plane. This is of importance to evaluate resolution-based content discovery in content-oriented network architectures: we identify scenarios where the cost of updating the control plane for content routing overwhelms the benefit of fetching the nearest copy. We also show how to minimize the cost of this overhead when associating costs to peering traffic and to internal traffic for network of caches. Autors: Bita Azimdoost;Cedric Westphal;Hamid R. Sadjadpour; Appeared in: IEEE Transactions on Communications Publication date: Jul 2017, volume: 65, issue:7, pages: 2943 - 2955 Publisher: IEEE
» Resonance Reduction for AC Drives With Small Capacitance in the DC Link
 Abstract:Pulse-width modulated ac drives equipped with a small dc-link capacitor are becoming an attractive solution for electric drive applications with moderate requirements for shaft dynamic performance. However, when these drives are fed from a weak grid, a resonance between the line side impedance and the dc-link capacitor appears. Due to this resonance, the total harmonic distortion and the partially weighted harmonic distortion of the line currents are increased, which may raise compatibility problems with the ac line harmonic standards. This paper proposes a novel dc-link voltage compensation method, which can reduce the amplitude of the aforementioned oscillation, while the large dc-link voltage variation, caused by the rectification, can be eliminated from the motor current. The method has been experimentally validated and the results show excellent performance. Autors: Laszlo Mathe;Lajos Török;Dong Wang;Dezso Sera; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3814 - 3820 Publisher: IEEE
» Resonances in Axially Symmetric Dielectric Objects
 Abstract:A high-order convergent and robust numerical solver is constructed and used to find complex eigenwavenumbers and electromagnetic eigenfields of dielectric objects with axial symmetry. The solver is based on Fourier-Nyström discretization of combined integral equations for the transmission problem and can be applied to demanding resonance problems at microwave, terahertz, and optical wavelengths. High achievable accuracy, even at very high wavenumbers, makes the solver ideal for benchmarking and for assessing the performance of general-purpose commercial software. Autors: Johan Helsing;Anders Karlsson; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Jul 2017, volume: 65, issue:7, pages: 2214 - 2227 Publisher: IEEE
» Resource Allocation and Outage Analysis for an Adaptive Cognitive Two-Way Relay Network
 Abstract:In this paper, an adaptive two-way relay cooperation scheme is studied for multiple-relay cognitive radio networks to improve the performance of secondary transmissions. The power allocation and relay selection schemes are derived to minimize the secondary outage probability where only statistical channel information is needed. Exact closed-form expressions for secondary outage probability are derived under a constraint on the quality of service of primary transmissions in terms of the required primary outage probability. To better understand the impact of primary user interference on secondary transmissions, we further investigate the asymptotic behaviors of the secondary relay network, including power allocation and outage probability, when the primary signal-to-noise ratio goes to infinity. Simulation results are provided to illustrate the performance of the proposed schemes. Autors: Qunwei Li;Pramod K. Varshney; Appeared in: IEEE Transactions on Wireless Communications Publication date: Jul 2017, volume: 16, issue:7, pages: 4727 - 4737 Publisher: IEEE
» Resource Allocation for D2D-Enabled Vehicular Communications
 Abstract:The widely deployed cellular network, assisted with device-to-device (D2D) communications, can provide a promising solution to support efficient and reliable vehicular communications. Fast channel variations caused by high mobility in a vehicular environment need to be properly accounted for when designing resource allocation schemes for the D2D-enabled vehicular networks. In this paper, we perform spectrum sharing and power allocation based only on slowly varying large-scale fading information of wireless channels. Pursuant to differing requirements for different types of links, i.e., high capacity for vehicle-to-infrastructure (V2I) links and ultrareliability for vehicle-to-vehicle (V2V) links, we attempt to maximize the ergodic capacity of the V2I connections while ensuring reliability guarantee for each V2V link. Sum ergodic capacity of all V2I links is first taken as the optimization objective to maximize the overall V2I link throughput. Minimum ergodic capacity maximization is then considered to provide a more uniform capacity performance across all V2I links. Novel algorithms that yield optimal resource allocation and are robust to channel variations are proposed. Their desirable performance is confirmed by computer simulation. Autors: Le Liang;Geoffrey Ye Li;Wei Xu; Appeared in: IEEE Transactions on Communications Publication date: Jul 2017, volume: 65, issue:7, pages: 3186 - 3197 Publisher: IEEE
» Resource Allocation in Wireless Powered Relay Networks: A Bargaining Game Approach
 Abstract:Information and power transfer in mobile relay networks have recently emerged simultaneously, where the relay can harvest the radio frequency (RF) energy and then use this energy for data forwarding and system operation. Most of the previous works do not consider that the relay may have its own objectives, such as using the harvested energy for its own transmission instead of maximizing transmission of the network. Therefore, in this paper, we propose a Nash bargaining approach to balance the information transmission efficiency of source–destination pairs and the harvested energy of the relay in a wireless powered relay network with multiple source–destination pairs and one relay. We analyze and prove that the Nash bargaining problem has several desirable properties such as the discreteness and quasi-concavity, when it is decomposed into three subproblems: the energy transmission power optimization, the power control for data transmission, and the time division between energy transmission and data transmission. Based on the theoretical analysis, we propose an alternating power control and time-division algorithm to find a suboptimal solution. Simulation results clearly show and demonstrate the properties of the problem and the convergence of our algorithm. Autors: Zijie Zheng;Lingyang Song;Dusit Niyato;Zhu Han; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Jul 2017, volume: 66, issue:7, pages: 6310 - 6323 Publisher: IEEE
» Resource Exchange in Smart Grid Connected Cooperative Cognitive Radio Networks
 Abstract:Wireless telecommunications is experiencing a massive penetration of wireless devices and an exponential growth in wireless applications. To accommodate the expected service requirements with the available radio resources, we present a new radio resource exchange scheme for a smart grid connected cognitive radio system, in which independently harvested energy can be stored in the smart grid in the form of on-grid credit. The secondary system will gain spectrum usage by either forwarding primary data or transferring energy credit directly to the primary system. In particular, to maximize the overall energy saving while meeting the throughput requirement, the utilities of both systems are optimized by jointly designing the subchannel assignment scheme with power control. First, for any given subchannel assignment, we have derived the optimal power allocated by both primary and secondary systems to each subchannel. Then, the characteristics of the subchannel assignment scheme are analyzed, and the complexity of finding the optimal assignment is reduced. Finally, a novel joint subchannel assignment and power control scheme is proposed to decide whether and how to cooperate by comparing the utilities of both systems with and without cooperation. Simulations results are presented to verify the optimality of the derived scheme. Autors: Xueqing Huang;Nirwan Ansari; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Jul 2017, volume: 66, issue:7, pages: 6291 - 6298 Publisher: IEEE
» Response-Time Analysis in Hierarchically-Scheduled Time-Partitioned Distributed Systems
 Abstract:This paper develops an offset-based response-time analysis technique for analyzing complex distributed real-time systems where processing and communication resources use the time-partitioning strategy to isolate the operation of separate software components. Time partitioning may be provided in the processors by an ARINC 653 compliant operating system, and in the networks via the TTP communication protocol. The software components executed by the system may themselves be distributed and complex, composed of many concurrent tasks and with one or more end-to-end flows that may have end-to-end timing requirements. The developed analysis supports hierarchical scheduling where a primary scheduler performs time partitioning into separate partitions, and secondary fixed-priority schedulers dispatch the different concurrent tasks inside each partition. It also supports end-to-end flows that are either synchronized with the partition schedule or not. This is the first time that this kind of analysis is developed. An evaluation of an improvement introduced in the analysis is discussed. Two representative case studies are described. Autors: J. Carlos Palencia;Michael González Harbour;J. Javier Gutiérrez;Juan M. Rivas; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Jul 2017, volume: 28, issue:7, pages: 2017 - 2030 Publisher: IEEE
» Retrievals of Lake Ice Thickness From Great Slave Lake and Great Bear Lake Using CryoSat-2
 Abstract:Satellite observations have revealed decreases in the duration of the seasonal snow and ice coverage of Great Slave Lake (GSL) and Great Bear Lake (GBL), large freshwater lakes in Northern Canada. However, limited information is available about ice thickness changes. Here, we present and validate a method to retrieve lake ice thickness using the CryoSat-2 (CS2) radar altimeter. These are the first satellite altimeter retrievals of lake ice thickness. Under optimal conditions, the CS2 signal is scattered from both the snow–ice and the ice–water interfaces, with returns from each interface being of sufficient power to be identified in the radar waveform. The distance between the scattering horizons is used to determine the ice thickness, similar to traditional ground penetrating radar measurements. The seasonal evolution of ice thickness of GBL and GSL is compared with in situ measurements, modeled ice thicknesses, and previous studies. The impact of ice and snow properties on signal penetration and the thickness retrieval are examined with synthetic aperture radar imagery. The CS2 ice thickness retrievals are able to observe the seasonal thickening of the lake ice and closely match the in situ measurements over both lakes (, m). Thickness retrievals of thin ice are limited by a minimum waveform peak separation of 2 range bins, approximately 0.26 m in ice. Although not designed for lake ice studies, CS2 and future SAR satellite altimeter missions offer new possibilities to monitor the ice and water levels of climatically sensitive and influential lakes. Autors: Justin F. Beckers;J. Alec Casey;Christian Haas; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Jul 2017, volume: 55, issue:7, pages: 3708 - 3720 Publisher: IEEE
» RISE-Based Adaptive Control of Hydraulic Systems With Asymptotic Tracking
 Abstract:Parametric uncertainty associated with unmodeled disturbance always exist in physical hydraulic systems, and complicate the advanced nonlinear controller design. In this paper, an adaptive compensation with a robust integral of the sign of the error (RISE) feedback is developed for high precise tracking control of hydraulic motion system. To handle both payload and hydraulic unknown parameters in one controller, a chain of integrator nonlinear system model is first derived, and an adaptive RISE controller is then proposed, in which adaptive law is synthesized to handle parametric uncertainty and RISE robust term to attenuate unmodeled disturbance. The major feature of the proposed controller is that it can theoretically guarantee asymptotic tracking performance with a continuous control input, in the presence of various parametric uncertainties and unmodeled disturbances such as unconsidered dynamics as well as external disturbances via Lyapunov analysis. However, the proposed controller takes the acceleration as a system state, which usually suffers heavy noise pollution and thus cannot be utilized directly in actual control. To solve this practical issue, in this paper, a tracking differentiator is employed to extract high-quality acceleration signal and to make the proposed controller feasible execution. The effectiveness of the proposed nonlinear controller is demonstrated via comparative experimental results. Autors: Jianyong Yao;Wenxiang Deng;Zongxia Jiao; Appeared in: IEEE Transactions on Automation Science and Engineering Publication date: Jul 2017, volume: 14, issue:3, pages: 1524 - 1531 Publisher: IEEE
» Risk Assessment of Multi-Timescale Cascading Outages Based on Markovian Tree Search
 Abstract:In the risk assessment of cascading outages, the rationality of simulation and efficiency of computation are both of great significance. To overcome the drawback of sampling-based methods that huge computation resources are required and the shortcoming of initial contingency selection practices that the dependencies in sequences of outages are omitted, this paper proposes a novel risk assessment approach by searching on Markovian Tree. The Markovian tree model is reformulated from the quasi-dynamic multitimescale simulation model proposed recently to ensure reasonable modeling and simulation of cascading outages. Then, a tree search scheme is established to avoid duplicated simulations on same cascade paths, significantly saving the computation time. To accelerate the convergence of a risk assessment, a risk estimation index is proposed to guide the search for states with major contributions to the risk, and the risk assessment is realized based on the risk estimation index with a forward tree search and backward update algorithm. The effectiveness of the proposed method is illustrated on a four-node power system, and its convergence profile as well as efficiency is demonstrated on the RTS-96 test system. Autors: Rui Yao;Shaowei Huang;Kai Sun;Feng Liu;Xuemin Zhang;Shengwei Mei;Wei Wei;Lijie Ding; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2887 - 2900 Publisher: IEEE
» Robot-Assisted Maintenance of Wireless Sensor Networks Using Wireless Energy Transfer
 Abstract:Wireless sensor networks (WSNs) have proven to be an effective and dynamic paradigm for many applications, including structural health monitoring and tracking systems. However, the supply of energy to the sensors plays a key role in the success of these applications as well as the design and deployment of these networks. Currently, most WSNs are powered by batteries, which must be replaced frequently, increasing maintenance costs and operational complexity. In this paper, we propose a practical framework, called wirelessly energy-charged (WINCH), for battery maintenance; it involves recharging sensor batteries using mobile robots. This framework integrates a routing process in which the cluster heads are selected optimally, as in the low-energy adaptive clustering hierarchy–centralized protocol (LEACH-C), and the robots visit the sites frequently based on need and place themselves in the optimal positions with respect to the selected cluster heads. This approach considerably reduces overhead compared with existing methods. Moreover, we have developed an empirical model of the energy charging rate for sensor nodes. We use this model to compute the amount of energy harvested by each sensor in the proximity of the mobile charger. Simulation experiments for a wide range of design parameters and using several metrics, such as energy consumption, network throughput, and coverage, demonstrate the effectiveness of the proposed framework compared with an existing work. Autors: Uthman Baroudi; Appeared in: IEEE Sensors Journal Publication date: Jul 2017, volume: 17, issue:14, pages: 4661 - 4671 Publisher: IEEE
» Robust $H_{\infty }$ Group Consensus for Interacting Clusters of Integrator Agents
 Abstract:In this technical note, we investigate the group consensus for networks of agents modeled by single-integrator with model uncertainty and external disturbance. By developing tools from algebraic graph theory, matrix analysis as well as Lyapunov stability theory, we are able to derive some sufficient conditions in terms of the structure and strength of the couplings among agents so as to guarantee the group consensus with desired performance. Such conditions are structural and easy to check. Furthermore, some adaptation laws are proposed to address the coupling strength problem arising from the consideration that the theoretical value is usually much larger than expected in practice. Finally, some simulation examples are presented to demonstrate the efficiency of the theoretical findings. Autors: Jiahu Qin;Qichao Ma;Wei Xing Zheng;Huijun Gao;Yu Kang; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3559 - 3566 Publisher: IEEE
» Robust Active Disturbance Rejection Control of Induction Motor Systems Based on Additional Sliding-Mode Component
 Abstract:This paper deals with motion control systems with induction motor, subject to severe requirements on both dynamics and steady-state behavior. The proposed control methodology could be viewed as an advancement of the standard field oriented control. It consists of two control loops, i.e., the rotor flux and the speed control loops, designed using the active disturbance rejection control method, with the aim to cope with both exogenous and endogenous disturbances, which are estimated by means of two linear extended state observers and then compensated. Moreover, with the aim of achieving total robustness, a sliding-mode based component is designed, in order to take into account disturbance estimation errors and uncertainties in the knowledge of the control gains. The effectiveness of this approach is shown by means of numerical simulations, and experiments carried out on a suitably developed test set-up. Finally, experimental comparisons between the proposed robust active disturbance rejection control, and the basic active disturbance rejection control are given. Autors: Francesco Alonge;Maurizio Cirrincione;Filippo D’Ippolito;Marcello Pucci;Antonino Sferlazza; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5608 - 5621 Publisher: IEEE
» Robust Adaptive Normalized Cross-Correlation for Stereo Matching Cost Computation
 Abstract:Stereo matching is a challenging task because stereo images are affected by many factors, such as radiometric distortion, sun and rain flare, flying snow, occlusion, textureless and noisy image regions, and object boundaries. However, most of the existing methods for stereo matching aim to solve only one specific problem. As a result, their performance is degraded significantly when operating with stereo images captured under a variety of scenes and conditions. In this paper, we propose a novel matching cost function based on adaptive normalized cross-correlation (ANCC). We demonstrate several weaknesses of ANCC and propose techniques to resolve them. In addition, we employ available information, such as intensity mean, intensity variance, and support window radius, to estimate the parameters of the proposed matching cost function. Compared with ANCC, the proposed matching cost function reduces the error rates from 24.1% to 17.8% in the Middlebury data set and from 64.1% to 26.4% in the KITTI data set. In addition, for noisy stereo pairs, the proposed function reduces the error rate from 73.6% to 37.3%. The qualitative and quantitative experimental results based on stereo images in different data sets under various conditions show that our proposed matching cost function outperforms state-of-the-art matching cost functions in indoor and outdoor stereo images having various radiometric distortions. Autors: Vinh Quang Dinh;Cuong Cao Pham;Jae Wook Jeon; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Jul 2017, volume: 27, issue:7, pages: 1421 - 1434 Publisher: IEEE
» Robust Attitude Stabilization for Nonlinear Quadrotor Systems With Uncertainties and Delays
 Abstract:Robust attitude stabilization problem is dealt with for quadrotor systems subject to nonlinear and coupling dynamics, uncertainties including parametric uncertainties, unmodeled uncertainties, and external disturbances, and time-varying state and input delays. A robust attitude stabilization controller is proposed consisting of a nominal state-feedback controller and a robust compensator. The nominal controller is designed for the uncertain and delay free model to achieve the desired control performances, while the robust compensator is added to restrain the effects of uncertainties and delays on the closed-loop control system. The design method leads to a linear time-invariant feedback controller and the resulted closed-loop control system has a feature of two-loop type. The robust uniform asymptotical stability and bounded-input bounded-state stability are proven. Experimental results on the quadrotor system are given to validate the effectiveness of the designed robust control method. Autors: Hao Liu;Jianxiang Xi;Yisheng Zhong; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5585 - 5594 Publisher: IEEE
» Robust Defense Strategy for Gas–Electric Systems Against Malicious Attacks
 Abstract:This paper proposes a methodology to identify and protect vulnerable components of connected gas and electric infrastructures from malicious attacks, and to guarantee a resilient operation by deploying valid corrective actions, while accounting for the interdependence of the gas pipeline network and power transmission network. The proposed mathematical formulation gives rise to to a trilevel optimization problem, where the lower level is a multiperiod economic dispatch of the gas–electric system and seeks operating strategies under available resources and given attack, the middle level distinguishes the most threatening attack on the coupled physical infrastructures, and the upper level provides optimal preventive decisions to reinforce the vulnerable components and increase the system resilience. By reformulating the lower level problem as a mixed integer linear programming, a nested column-and-constraint generation algorithm is developed to solve the min–max–min model. Case studies on two test systems demonstrate the effectiveness and efficiency of the proposed methodology. Autors: Cheng Wang;Wei Wei;Jianhui Wang;Feng Liu;Feng Qiu;Carlos M. Correa-Posada;Shengwei Mei; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2953 - 2965 Publisher: IEEE
» Robust Nonlinear Regulation: Continuous-Time Internal Models and Hybrid Identifiers
 Abstract:The paper deals with the problem of robust output regulation for minimum-phase nonlinear systems in a semiglobal setting. We present a different perspective to the problem of adaptive regulation in which prediction error identification methods, which are routinely used in other control contexts, can be adopted to design robust nonlinear regulators. The proposed control structure combines continuous-time dynamics and “hybrid identifiers”, the latter specifically designed to estimate the actual steady-state control law. The proposed framework encompasses existing frameworks proposed so far in the nonlinear continuous-time literature. Autors: Francesco Forte;Lorenzo Marconi;Andrew R. Teel; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3136 - 3151 Publisher: IEEE
» Robust Operation of Microgrids via Two-Stage Coordinated Energy Storage and Direct Load Control
 Abstract:This paper proposes a robust optimization approach for optimal operation of microgrids. The uncertain output variation of renewable energy sources (RESs) is addressed by collaboratively scheduling of energy storage (ES) and direct load control (DLC) through a two-stage complementary framework: an hour-ahead charging/discharging of ES and a quarter-hour-ahead activation of DLC. The objective is to maximize the total profit of the microgrid considering operation and maintenance costs of ES units, wind turbines and photovoltaics, and transaction with main grid and customer loads. Assuming the power output of RES randomly varies within a bounded uncertainty set, the problem is modeled to a two-stage robust optimization model and solved by a column-and-constraint generation algorithm. Compared with conventional operation methods, the ES and DLC are coordinated in different time-scales, and RES uncertainties are fully addressed during operation decision-making, ensuring the solutions to be optimal and robust for any realization of uncertainty. The proposed methodology is verified on the IEEE 33-bus distribution system through a wide range of different tests. Autors: Cuo Zhang;Yan Xu;Zhao Yang Dong;Jin Ma; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2858 - 2868 Publisher: IEEE
» Robust Stabilization for Uncertain Saturated Time-Delay Systems: A Distributed-Delay-Dependent Polytopic Approach
 Abstract:This technical note investigates the robust stabilization problem for uncertain linear systems with discrete and distributed delays under saturated state feedback. Different from the existing approaches, a distributed-delay-dependent polytopic approach is proposed in this technical note, and the saturation nonlinearity is represented as the convex combination of state feedback and auxiliary distributed-delay feedback. Then, by incorporating an appropriate augmented Lyapunov-Krasovskii (L-K) functional and some integral inequalities, the less conservative stabilization and robust stabilization conditions are proposed in terms of linear matrix inequalities (LMIs). The effectiveness and reduced conservatism of the proposed conditions are illustrated by numerical examples. Autors: Yonggang Chen;Shumin Fei;Yongmin Li; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3455 - 3460 Publisher: IEEE
» Robust Stochastic Design of Signal-Controlled Road Network Under Uncertain Travel Demands
 Abstract:A robust stochastic design and signal control (RoSign) is considered for urban traffic network under uncertain travel demand. The optimal solutions for RoSign can be cast as a stochastic mathematical program with equilibrium constraints (SMPEC) and efficiently solved by a stochastic projected cutting plane (SPC) with global convergence. While robust optimization is considered a good alternative against high-consequence realization of uncertainty, a flexible signal timing using a budget of uncertainty in demand is investigated. Sensitivity analysis of SPC against budgeted uncertainty in travel demand is performed. Numerical computation and comparison are also made with other heuristics using real-data road networks. Results indicate that SPC enjoyed a greater gain of achieving road network robustness whilst incurring less sub-optimality loss against uncertain demand as compared to other alternatives. Autors: Suh-Wen Chiou; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3152 - 3164 Publisher: IEEE
» Robust Timing Calibration for PET Using L1-Norm Minimization
 Abstract:Positron emission tomography (PET) relies on accurate timing information to pair two 511-keV photons into a coincidence event. Calibration of time delays between detectors becomes increasingly important as the timing resolution of detector technology improves, as a calibration error can quickly become a dominant source of error. Previous work has shown that the maximum likelihood estimate of these delays can be calculated by least squares estimation, but an approach is not tractable for complex systems and degrades in the presence of randoms. We demonstrate the original problem to be solvable iteratively using the LSMR algorithm. Using the LSMR, we solve for 60 030 delay parameters, including energy-dependent delays, in 4.5 s, using 1 000 000 coincidence events for a two-panel system dedicated to clinical locoregional imaging. We then extend the original least squares problem to be robust to random coincidences and low statistics by implementing -norm minimization using the alternating direction method of the multipliers (ADMM) algorithm. The ADMM algorithm converges after six iterations, or 20.6 s, and improves the timing resolution from 64.7 ± 0.1s full width at half maximum (FWHM) uncalibrated to 15.63 ± 0.02ns FWHM. We also demonstrate this algorithm’s applicability to commercial systems using a GE Discovery 690 PET/CT. We scan a rotating transmission source, and after subtracting the 511-keV photon time-of-flight due to the source position, we calculate 13 824 per-crystal delays using 5 000 000 coincidence events in 3.78 s with three iterations, while showing a timing resolution improvement that is significantly better than previous calibration methods in the literature. Autors: David L. Freese;David F. C. Hsu;Derek Innes;Craig S. Levin; Appeared in: IEEE Transactions on Medical Imaging Publication date: Jul 2017, volume: 36, issue:7, pages: 1418 - 1426 Publisher: IEEE
» Rotor Design for High-Speed High-Power Permanent-Magnet Synchronous Machines
 Abstract:Permanent-magnet synchronous machines (PMSMs) are considered a very promising machine type for high-speed (HS) applications. As permanent-magnet (PM) materials are generally fragile, a high-strength sleeve is required to protect the PMs from damage due to the extreme centrifugal forces. The rotor sleeve occupies space of the effective airgap of the PMSMs; therefore, it is difficult to perform the electromagnetic (EM) design without an accurate estimation of the sleeve thickness, which is determined by mechanical issues. In this paper, an integrated mechanical- EM design method is proposed for the rotor design of HS PMSMs. A 200-kW 40 000 r/min surface mounted PM machine is taken to illustrate the design procedure of the proposed method. Three commonly used sleeve materials are investigated and their mechanical performances are analyzed. The optimal dimensions for the rotors with different sleeves are obtained by considering the strength and EM limits. The EM, thermal, and rotor dynamic performances of the designed rotors are analyzed and compared. In the end, a new rotor sleeve topology is proposed to reduce the rotor eddy current losses. Autors: Haiyang Fang;Ronghai Qu;Jian Li;Pei Zheng;Xinggang Fan; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3411 - 3419 Publisher: IEEE
» Rotor Notching for Electromagnetic Noise Reduction of Induction Motors
 Abstract:This paper presents a new technique, notching the induction motor rotor core, so as to reduce the electromagnetic noise by suppressing the vibration due to the rotor slot permeance harmonics. First, the principle of such technique is presented along with theoretical analysis. Then, finite element method is used to calculate the Maxwell force harmonics and the vibration spectra of a 5.5 kW 3000 r/m commercial induction motor and a modified motor. Finally, experimental results are given to validate the proposed technique by testing the vibration and acoustic noise spectra of the two induction motors. It is shown that the modified motor has about 5 dB(A) reduction of the overall sound pressure level compared with the commercial one. Autors: Gui-Yu Zhou;Jian-Xin Shen; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3361 - 3370 Publisher: IEEE
» Rotor Surface Ferrite Permanent Magnets in Electrical Machines: Advantages and Limitations
 Abstract:Permanent-magnet synchronous machines (PMSM) are gaining a foothold in a growing number of applications. However, the high cost of these machines compared with the prices of induction motors, whose production process is mature and material costs are low, limits the use of PMSMs with rare-earth permanent magnets in many potential cases. A viable design solution for a PMSM cost reduction is to use low-cost ferrite magnets instead of rare-earth ones. Nevertheless, it is challenging to apply ferrite magnets to a high-power rotor surface magnet PMSM because of their weaker magnetic properties compared with the rare-earth magnets and the risk of irreversible demagnetization. This paper aims to investigate the boundaries and limiting factors for achieving the maximum tangential stress and linear current density at a certain air gap diameter by using rotor surface ferrite magnets. The computed results are validated by a prototype, which was designed within the described boundaries. Autors: Ilya Petrov;Markku Niemelä;Pavel Ponomarev;Juha Pyrhönen; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5314 - 5322 Publisher: IEEE
» Rotor Temperature Estimation in Doubly-Fed Induction Machines Using Rotating High-Frequency Signal Injection
 Abstract:Thermal monitoring is a common feature in most electric machine drives since thermal overloading is one of the most common causes of motor failures. Contact-type sensors are normally used to measure the stator temperature in electric machines. However, use of this type of sensor is not advisable in the rotor as it requires cabling to a rotating part or the use of a wireless transmission system. Consequently, measurement of the rotor temperature is not easy in practice and is not normally implemented in standard machines. An alternative to rotor temperature measurement is rotor temperature estimation. To date, only thermal models have been used for rotor temperature estimation in doubly-fed induction machines (DFIMs). This paper proposes rotor temperature estimation in DFIMs using high-frequency signal injection. The proposed method estimates the rotor temperature from the rotor high frequency resistance, which is a function of the rotor windings temperature. The method does not interfere with the normal operation of the drive and can be implemented in existing DFIM drives without requiring additional hardware. Autors: David Diaz Reigosa;Juan Manuel Guerrero;Alberto B. Diez;Fernando Briz; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3652 - 3662 Publisher: IEEE
» Rotor/Stator Inter-Turn Short Circuit Fault Detection for Saturable Wound-Rotor Induction Machine by Modified Magnetic Equivalent Circuit Approach
 Abstract:This paper presents a new method to model healthy and faulty wound-rotor induction machines (WRIMs) with and without inter-turn short circuit fault by a single set of equations. The model is presented for a machine with arbitrary pole, and rotor and stator slot numbers. A single set of equations, including both electric and magnetic parts, is solved to obtain full dynamic behavior of the machine. Therefore, the modified magnetic equivalent circuit with non-linear elements is used for modeling and a numerical technique is employed to solve the non-linear equations. The proposed modified method has a simple calculation procedure in comparison with the conventional magnetic equivalent circuit method. Solving the electric and magnetic equations by a single set of equations is the main advantage of the presented method, which is proposed for a WRIM machine, for the first time. In addition, to increase the accuracy, the saturation phenomenon is also considered in the model. Due to the saturation effect, there are some non-linear algebraic magnetic equations, which should be simultaneously solved with differential equations. A trapezoidal technique is used to convert differential equations to algebraic ones. To solve the non-linear equations, non-linear equations, Newton Newton–Raphson method is employed. Current signature analysis is used for rotor and stator inter-turn short circuit fault detection. Finally, the finite-element method is used to verify the effectiveness of the proposed modeling method. It is worth noting that the proposed method can model a healthy and faulty machine with different faults by a single model. Autors: Peyman Naderi;Abbas Shiri; Appeared in: IEEE Transactions on Magnetics Publication date: Jul 2017, volume: 53, issue:7, pages: 1 - 13 Publisher: IEEE
» Rural Macrocell Path Loss Models for Millimeter Wave Wireless Communications
 Abstract:Little is known about millimeter wave (mmWave) path loss in rural areas with tall base station antennas; yet, as shown here, surprisingly long distances (greater than 10 km) can be achieved in clear weather with less than 1 W of power. This paper studies past rural macrocell (RMa) propagation models and the current third generation partnership project (3GPP) RMa path loss models for frequencies from 0.5 to 30 GHz adopted from the International Telecommunications Union-Radiocommunication Sector (ITU-R). We show that 3GPP and ITU-R RMa path loss models were derived for frequencies below 6 GHz, yet are being asserted for use up to 30 GHz. Until this paper, there has not been published data to support mmWave RMa path loss models. In this paper, 73-GHz measurements in rural Virginia are used to develop a new RMa path loss model that is more accurate and easier to apply for varying transmitter antenna heights than the existing 3GPP/ITU-R RMa path loss models, and may be used for frequencies from 0.5 to 100 GHz. The measurement system used here has a measurement range comparable to a wideband (800-MHz radio frequency bandwidth) channel sounder with 21.7-dBW effective isotropic radiated power. Measured data verify a new path loss model that uses a close-in free space reference distance with a novel height-dependent path loss exponent (CIH model). This work shows that the CIH model is accurate and stable, and is frequency-independent beyond the first meter of propagation, and effectively models the path loss dependence on base station height in rural channels. Autors: George R. MacCartney;Theodore S. Rappaport; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Jul 2017, volume: 35, issue:7, pages: 1663 - 1677 Publisher: IEEE
» Saliency Detection by Fully Learning a Continuous Conditional Random Field
 Abstract:Salient object detection is aimed at detecting and segmenting objects that human eyes are most focused on when viewing a scene. Recently, conditional random field (CRF) is drawn renewed interest, and is exploited in this field. However, when utilizing a CRF with unary and pairwise potentials having essential parameters, most existing methods only employ manually designed parameters, or learn parameters partly for the unary potentials. Observing that the saliency estimation is a continuous labeling issue, this paper proposes a novel data-driven scheme based on a special CRF framework, the so-called continuous CRF (C-CRF), where parameters for both unary and pairwise potentials are jointly learned. The proposed C-CRF learning provides an optimal way to integrate various unary saliency features with pairwise cues to discover salient objects. To the best of our knowledge, the proposed scheme is the first to completely learn a C-CRF for saliency detection. In addition, we propose a novel formulation of pairwise potentials that enables learning weights for different spatial ranges on a superpixel graph. The proposed C-CRF learning-based saliency model is tested on 6 benchmark datasets and compared with 11 existing methods. Our results and comparisons have provided further support to the proposed method in terms of precision-recall and F-measure. Furthermore, incorporating existing saliency models with pairwise cues through the C-CRF are shown to provide marked boosting performance over individual models. Autors: Keren Fu;Irene Yu-Hua Gu;Jie Yang; Appeared in: IEEE Transactions on Multimedia Publication date: Jul 2017, volume: 19, issue:7, pages: 1531 - 1544 Publisher: IEEE
» Sb-Doped $p$ -MgZnO/ $n$ -Si Heterojunction UV Photodetector Fabricated by Dual Ion Beam Sputtering
 Abstract:Sb-doped p-Mg0.1Zn0.9O/-Si-based heterojunction ultraviolet photodetectors were fabricated using dual ion beam sputtering. Current–Voltage measurements showed good rectifying behavior in fabricated devices with rectifying ratio as high as 251.35 at ± 4 V. The detectors exhibited good ultraviolet spectral response having peak responsivity of 0.025 A/W (at 310 nm) and 0.32 A/W (at 320 nm) at −30 V. The values of peak responsivity and external quantum efficiency increased from 1.7 mA/W and 0.75% (at 0 V) to 0.32 A/W and 134.26% (at −30 V), respectively. The value of detectivity of heterojunction devices was calculated to be cm Hz at −5 V. Autors: Ritesh Bhardwaj;Pankaj Sharma;Rohit Singh;Shaibal Mukherjee; Appeared in: IEEE Photonics Technology Letters Publication date: Jul 2017, volume: 29, issue:14, pages: 1215 - 1218 Publisher: IEEE
» Scalable Certificate Revocation Schemes for Smart Grid AMI Networks Using Bloom Filters
 Abstract:Given the scalability of the advanced metering infrastructure (AMI) networks, maintenance and access of certificate revocation lists (CRLs) pose new challenges. It is inefficient to create one large CRL for all the smart meters (SMs) or create a customized CRL for each SM since too many CRLs will be required. In order to tackle the scalability of the AMI network, we divide the network into clusters of SMs, but there is a tradeoff between the overhead at the certificate authority (CA) and the overhead at the clusters. We use Bloom filters to reduce the size of the CRLs in order to alleviate this tradeoff by increasing the clusters’ size with acceptable overhead. However, since Bloom filters suffer from false positives, there is a need to handle this problem so that SMs will not discard important messages due to falsely identifying the certificate of a sender as invalid. To this end, we propose two certificate revocation schemes that can identify and nullify the false positives. While the first scheme requires contacting the gateway to resolve them, the second scheme requires the CA additionally distribute the list of certificates that trigger false positives. Using mathematical models, we have demonstrated that the probability of contacting the gateway in the first scheme and the overhead of the second scheme can be very low by properly designing the Bloom filters. In order to assess the scalability and validate the mathematical formulas, we have implemented the proposed schemes using Visual C. The results indicate that our schemes are much more scalable than the conventional CRL and the mathematical and simulation results are almost identical. Moreover, we simulated the distribution of the CRLs in a wireless mesh-based AMI network using ns-3 network simulator and assessed its distribution overhead. Autors: Khaled Rabieh;Mohamed M.E.A. Mahmoud;Kemal Akkaya;Samet Tonyali; Appeared in: IEEE Transactions on Dependable and Secure Computing Publication date: Jul 2017, volume: 14, issue:4, pages: 420 - 432 Publisher: IEEE
» Scalable Face Track Retrieval in Video Archives Using Bag-of-Faces Sparse Representation
 Abstract:Huge video archives consisting of news programs, dramas, movies, and Web videos (e.g., YouTube) are available in our daily life. In all these videos, human is usually one of the most important subjects. Using state-of-the-art techniques, we can efficiently detect and track faces in the videos. In order to organize large-scale face tracks, containing sequences of (detected) consecutive faces in the videos, we propose an efficient method to retrieve human face tracks using bag-of-faces sparse representation (BoF-SR). Using the proposed method, a face track is encoded as a single BoF-SR, therefore allowing an efficient indexing method to handle large-scale data. To further consider the possible variations in face tracks, we generalize our method to find multiple SRs, in an unsupervised manner, to represent a bag of faces and balance the tradeoff between performance and retrieval time. The experimental results on two real-world (million-scale) data sets confirm that the proposed methods achieve significant performance gains compared with different state-of-the-art methods. Autors: Bor-Chun Chen;Yan-Ying Chen;Yin-Hsi Kuo;Thanh Duc Ngo;Duy-Dinh Le;Shin’ichi Satoh;Winston H. Hsu; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Jul 2017, volume: 27, issue:7, pages: 1595 - 1603 Publisher: IEEE
» Scalable Single Source Shortest Path Algorithms for Massively Parallel Systems
 Abstract:We consider the single-source shortest path (SSSP) problem: given an undirected graph with integer edge weights and a source vertex , find the shortest paths from to all other vertices. In this paper, we introduce a novel parallel algorithm, derived from the Bellman-Ford and Delta-stepping algorithms. We employ various pruning techniques, such as edge classification and direction-optimization, to dramatically reduce inter-node communication traffic, and we propose load balancing strategies to handle higher-degree vertices. These techniques are particularly effective on power-law graphs, as demonstrated by our extensive performance analysis. In the largest tested configuration, an R-MAT graph with vertices and edges on 32,768 Blue Gene/Q nodes, we have achieved a processing rate of three Trillion Edges Per Second (TTEPS), a four orders of magnitude improvement over the best published results. Autors: Venkatesan T. Chakaravarthy;Fabio Checconi;Prakash Murali;Fabrizio Petrini;Yogish Sabharwal; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Jul 2017, volume: 28, issue:7, pages: 2031 - 2045 Publisher: IEEE
» Scalable Spectrum Allocation and User Association in Networks With Many Small Cells
 Abstract:A scalable framework is developed to allocate radio resources across a large number of densely deployed small cells with given traffic statistics on a slow timescale. Joint user association and spectrum allocation is first formulated as a convex optimization problem by dividing the spectrum among all possible transmission patterns of active access points (APs). To improve scalability with the number of APs, the problem is reformulated using local patterns of interfering APs. To maintain global consistency among local patterns, inter-cluster interaction is characterized as hyper-edges in a hyper-graph with nodes corresponding to subcarriers allocated to APs. A scalable solution is obtained by iteratively solving a convex optimization problem for bandwidth allocation with reduced complexity and followed by a global spectrum allocation using hyper-graph coloring. Numerical results demonstrate the proposed solution for a network with 100 APs and several hundred user equipment. For a given quality of service, the proposed scheme can often increase the network capacity severalfold compared with assigning each user to the strongest AP with full-spectrum reuse. Autors: Binnan Zhuang;Dongning Guo;Ermin Wei;Michael L. Honig; Appeared in: IEEE Transactions on Communications Publication date: Jul 2017, volume: 65, issue:7, pages: 2931 - 2942 Publisher: IEEE
» Scanned 3-D Intracardiac ARFI and SWEI for Imaging Radio-Frequency Ablation Lesions
 Abstract:Radio-frequency ablation (RFA) is used to locally disrupt electrical propagation in myocardium and treat arrhythmias, and direct visualization of ablation lesions by acoustic radiation force methods may benefit RFA procedures. This paper compares four imaging modalities, B-mode, acoustic radiation force impulse (ARFI), single-track-location shear wave elasticity imaging (STL-SWEI), and multiple-track-location shear wave elasticity imaging (MTL-SWEI), in their ability to resolve RFA lesions in four ex vivo experiments. Ablation lesions are shown to be marked by at least a local halving of ARFI displacements and doubling of shear wave speeds. In a controlled ablation of ex vivo porcine and canine cardiac tissue, STL-SWEI and ARFI are shown to have a similar CNR, better than MTL-SWEI and B-mode. The SWEI modalities are demonstrated to have improved imaging of distal lesion boundaries. Gaps smaller than 5 mm are visualized in ablation lines made of discretely spaced ablations, and complex structures are reconstructed through depth in an “x” ablation experiment. Scans of suspended atria show increased noise, but successfully visualize ablations in ARFI, MTL-SWEI, and STL-SWEI. Autors: Peter Hollender;Lily Kuo;Virginia Chen;Stephanie Eyerly;Patrick Wolf;Gregg Trahey; Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Publication date: Jul 2017, volume: 64, issue:7, pages: 1034 - 1044 Publisher: IEEE
» Scanning the Issue
 Abstract:A Survey on Approaches of Motion Mode Recognition Using SensorsM. Elhoushi, J. Georgy, A. Noureldin, and M. J. KorenbergRecognition of the mode of motion or mode of transit of the user or platform carrying a device is needed in portable navigation, as well as other technological domains. An extensive survey on motion mode recognition approaches is provided in this paper. The survey compares and describes motion mode recognition approaches from different viewpoints: usability and convenience, types of devices in terms of setup mounting and data acquisition, various types of sensors used, signal processing methods employed, features extracted, and classification techniques. This paper ends with a quantitative comparison of the performance of motion mode recognition modules developed by researchers in different domains. Autors: Petros Ioannou; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Jul 2017, volume: 18, issue:7, pages: 1657 - 1661 Publisher: IEEE
» Scatter Component Analysis: A Unified Framework for Domain Adaptation and Domain Generalization
 Abstract:This paper addresses classification tasks on a particular target domain in which labeled training data are only available from source domains different from (but related to) the target. Two closely related frameworks, domain adaptation and domain generalization, are concerned with such tasks, where the only difference between those frameworks is the availability of the unlabeled target data: domain adaptation can leverage unlabeled target information, while domain generalization cannot. We propose Scatter Component Analyis (SCA), a fast representation learning algorithm that can be applied to both domain adaptation and domain generalization. SCA is based on a simple geometrical measure, i.e., scatter, which operates on reproducing kernel Hilbert space. SCA finds a representation that trades between maximizing the separability of classes, minimizing the mismatch between domains, and maximizing the separability of data; each of which is quantified through scatter. The optimization problem of SCA can be reduced to a generalized eigenvalue problem, which results in a fast and exact solution. Comprehensive experiments on benchmark cross-domain object recognition datasets verify that SCA performs much faster than several state-of-the-art algorithms and also provides state-of-the-art classification accuracy in both domain adaptation and domain generalization. We also show that scatter can be used to establish a theoretical generalization bound in the case of domain adaptation. Autors: Muhammad Ghifary;David Balduzzi;W. Bastiaan Kleijn;Mengjie Zhang; Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence Publication date: Jul 2017, volume: 39, issue:7, pages: 1414 - 1430 Publisher: IEEE
» Sci Chic: Combining Art, Engineering, and Fashion
 Abstract:In the spring of 2015, my junior year as a mechanical engineering major, I was serving as the president of the University of Florida (UF) chapter of the Society of Women Engineers (SWE). That semester, we had organized a brand-new event for our SWE chapter, Three-Dimensional (3-D) Printing Outreach Day. In partnership with our campus science library, more than 100 students were brought to UF's campus to learn about 3-D modeling, 3-D printing, and engineering. This day served as a moment of personal and entrepreneurial inspiration for me that led to the creation of my company. Autors: Erin Winick; Appeared in: IEEE Potentials Publication date: Jul 2017, volume: 36, issue:4, pages: 19 - 23 Publisher: IEEE
» Sea Wind Extraction From RADARSAT-2 and Scatterometer Data Over the Gulf of Mexico
 Abstract:A marine wind field extraction methodology that produced results with km of spatial resolution using RADARSAT-2 wide and ScanSAR narrow acquisition modes was applied over the Gulf of Mexico. Bootstrap method with median values was applied on the spatial resampling step and showed to be efficient to eliminate extreme values from double bounce by targets on the water, which are undesirable for wind estimation, without the need of postprocess to exclude outliers. An empirical CMOD-IFR2 model was used with wind direction information to initialize the model obtained from QuikSCAT scatterometer. The estimated values were compared with measurements from four anemometers. Modeled wind fields were resampled at the same QuikSCAT spatial resolution with the bootstrap method, and correlation coefficients were found to be greater than 0.75 for all ScanSAR narrow images. The initial spatial resolution probably plays an important issue on the results, as the correlation coefficients for all wide images were almost zero. This hypothesis must be further investigated. Autors: Douglas Fraga Rodrigues;Luiz Landau;Audalio Rebelo Torres Junior;Regina Lanzillotti;Fernando Pellon de Miranda; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Jul 2017, volume: 14, issue:7, pages: 1007 - 1011 Publisher: IEEE
» Searching Trajectories by Regions of Interest
 Abstract:With the increasing availability of moving-object tracking data, trajectory search is increasingly important. We propose and investigate a novel query type named trajectory search by regions of interest (TSR query). Given an argument set of trajectories, a TSR query takes a set of regions of interest as a parameter and returns the trajectory in the argument set with the highest spatial-density correlation to the query regions. This type of query is useful in many popular applications such as trip planning and recommendation, and location based services in general. TSR query processing faces three challenges: how to model the spatial-density correlation between query regions and data trajectories, how to effectively prune the search space, and how to effectively schedule multiple so-called query sources. To tackle these challenges, a series of new metrics are defined to model spatial-density correlations. An efficient trajectory search algorithm is developed that exploits upper and lower bounds to prune the search space and that adopts a query-source selection strategy, as well as integrates a heuristic search strategy based on priority ranking to schedule multiple query sources. The performance of TSR query processing is studied in extensive experiments based on real and synthetic spatial data. Autors: Shuo Shang;Lisi Chen;Christian S. Jensen;Ji-Rong Wen;Panos Kalnis; Appeared in: IEEE Transactions on Knowledge and Data Engineering Publication date: Jul 2017, volume: 29, issue:7, pages: 1549 - 1562 Publisher: IEEE
» Secrecy Outage for Wireless Sensor Networks
 Abstract:This letter addresses physical layer security (PLS) for a wireless sensor network, in which multiple sensor nodes communicate with a single sink in the presence of an eavesdropper. Under the assumption of sink using outdated channel state information (CSI) of the eavesdropper link, the outage probability of achievable secrecy rate under Weibull fading is investigated and its analytical expressions are derived. Specifically, we consider sensor scheduling to enhance PLS, thereby, we quantify the degradation in outage probability due to outdated CSI under the best-node scheduling scheme and compare it with conventional round-robin scheduling. Finally, we analyze secrecy outage probability conditional on successful transmission and provide practical insights into the effect of outdated CSI of the eavesdropper. The derived theoretical results are validated through simulations. Autors: Furqan Jameel;Shurjeel Wyne;Ioannis Krikidis; Appeared in: IEEE Communications Letters Publication date: Jul 2017, volume: 21, issue:7, pages: 1565 - 1568 Publisher: IEEE
» Secure Multiple Amplify-and-Forward Relaying Over Correlated Fading Channels
 Abstract:This paper quantifies the impact of correlated fading on secure communication of multiple amplify-and-forward (AF) relaying networks. In such a network, the base station (BS) is equipped with multiple antennas and communicates with the destination through multiple AF relays, while the message from the relays can be overheard by an eavesdropper. We focus on the practical communication scenario, where the main and eavesdropper’s channels are correlated. In order to enhance the transmission security, transmit antenna selection is performed at the BS, and the best relay is chosen according to the full- or partial-relay selection criterion, which relies on the dual-hop relay channels or the second-hop relay channels, respectively. For these criteria, we study the impact of correlated fading on the network secrecy performance, by deriving an analytical approximation for the secrecy outage probability and an asymptotic expression for the high main-to-eavesdropper ratio. From these results, it is concluded that the channel correlation is always beneficial to the secrecy performance of full relay selection. However, it deteriorates the secrecy performance if partial-relay selection is used, when the number of antennas at the BS is less than the number of relays. Autors: Lisheng Fan;Rui Zhao;Feng-Kui Gong;Nan Yang;George K. Karagiannidis; Appeared in: IEEE Transactions on Communications Publication date: Jul 2017, volume: 65, issue:7, pages: 2811 - 2820 Publisher: IEEE
» Security-Adaptive Voltage Conversion as a Lightweight Countermeasure Against LPA Attacks
 Abstract:A voltage converter with adaptive security features is proposed as a lightweight countermeasure against leakage power analysis (LPA) attacks. When an LPA attack is sensed by the proposed security-adaptive (SA) voltage converter, a discharging resistor starts sinking redundant current to alter the signature of the load power dissipation. The power dissipation induced by the discharging resistor is scrambled by the SA voltage converter to maximize the amount of the inserted noise to the input power profile of the cryptographic against LPA attacks. As compared with a conventional cryptographic circuit that does not house any countermeasure, the lowest measurement-to-disclose value of a cryptographic circuit that employs the proposed voltage converter can be enhanced over 6145 times against LPA attacks. Autors: Weize Yu;Selçuk Köse; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Jul 2017, volume: 25, issue:7, pages: 2183 - 2187 Publisher: IEEE
» Segment-Oriented Depiction and Analysis for Hyperspectral Image Data
 Abstract:A novel segment-oriented dictionary learning (SeODL) framework for hyperspectral image (HSI) classification is proposed. Differing from existing HSI classification methods which directly process the original whole spectral curves of pixels, our work focuses on local segment analysis to achieve fine depiction and effective exploitation. Viewing the separated segment as a basic processing unit, we first cluster them into two sets with the homogeneity in trend and fluctuation, and then two small dictionaries can be quickly learned. Second, to get meticulous and discriminability enhanced segment-oriented representations (SORs), the segments of the training and test pixels are coded on a novel binary-separated coding strategy. The coding stage for obtaining SORs is sped up by the employment of our proposed enhanced orthogonal matching pursuit technique. A characteristic splicing classifier with high performance can be trained using these SORs of the training pixels. Finally, a spiral searching strategy and a multiple majority-voting method are adopted for fully spatial information incorporation of the test pixels whose final SORs will be embedded into the trained characteristics splicing classifier to ascertain the labels. Experimental results on three real HSI data sets demonstrate the superiority of the proposed SeODL framework over several well-known classification algorithms in terms of classification accuracies. Autors: Jihao Yin;Hui Qv;Xiaoyan Luo;Xiuping Jia; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Jul 2017, volume: 55, issue:7, pages: 3982 - 3996 Publisher: IEEE
» Segmentation of Pathological Structures by Landmark-Assisted Deformable Models
 Abstract:Computerized segmentation of pathological structures in medical images is challenging, as, in addition to unclear image boundaries, image artifacts, and traces of surgical activities, the shape of pathological structures may be very different from the shape of normal structures. Even if a sufficient number of pathological training samples are collected, statistical shape modeling cannot always capture shape features of pathological samples as they may be suppressed by shape features of a considerably larger number of healthy samples. At the same time, landmarking can be efficient in analyzing pathological structures but often lacks robustness. In this paper, we combine the advantages of landmark detection and deformable models into a novel supervised multi-energy segmentation framework that can efficiently segment structures with pathological shape. The framework adopts the theory of Laplacian shape editing, that was introduced in the field of computer graphics, so that the limitations of statistical shape modeling are avoided. The performance of the proposed framework was validated by segmenting fractured lumbar vertebrae from 3-D computed tomography images, atrophic corpora callosa from 2-D magnetic resonance (MR) cross-sections and cancerous prostates from 3D MR images, resulting respectively in a Dice coefficient of 84.7 ± 5.0%, 85.3 ± 4.8% and 78.3 ± 5.1%, and boundary distance of 1.14 ± 0.49mm, 1.42 ± 0.45mm and 2.27 ± 0.52mm. The obtained results were shown to be superior in comparison to existing deformable model-based segmentation algorithms. Autors: Bulat Ibragimov;Robert Korez;Boštjan Likar;Franjo Pernuš;Lei Xing;Tomaž Vrtovec; Appeared in: IEEE Transactions on Medical Imaging Publication date: Jul 2017, volume: 36, issue:7, pages: 1457 - 1469 Publisher: IEEE
» Selected Prediction Vectors Based FS-PTC for 3L-NPC Inverter Fed Motor Drives
 Abstract:Computational burden is a major hurdle for practical implementation of finite-state predictive torque control (FS-PTC) of motor drive fed by a multilevel inverter. One of the reasons of computational complexity is that all voltage vectors are evaluated for prediction and actuation. This paper proposes a reduced number of voltage vectors for the prediction and actuation, which are called prediction vectors in FS-PTC. The performance is investigated for a three-level neutral-point clamped inverter fed motor drive in terms of torque and flux response, stator current total harmonic distortion, robustness, average switching frequency, and neutral-point voltage variation. The number of prediction vectors is reduced based on the position of stator flux and the deviation in stator flux from its reference. Experimental results confirm that the computational burden could be reduced by 38%, while the dynamic performance is comparable with the conventional all voltage vectors based FS-PTC. Autors: Md. Habibullah;Dylan Dah-Chuan Lu;Dan Xiao;Ilham Osman;Muhammed Fazlur Rahman; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3588 - 3597 Publisher: IEEE
» Sensitivity of Manufacturing Tolerances on Cogging Torque in Interior Permanent Magnet Machines With Different Slot/Pole Number Combinations
 Abstract:The cogging torque is usually very sensitive to the manufacturing tolerances during machine mass production, and this paper investigates the different sensitivities between interior permanent magnet (IPM) machines with different slot/pole number combinations. Exemplified by two typical combinations, i.e., 12-slot/8-pole and 12-slot/10-pole designs, the fundamental performance is first analyzed under ideal conditions. Then, with the tolerances of permanent magnet diversity and tooth bulges considered, the most sensitive cases are identified for the two machines, based on which the ultimate values of additional cogging torques are obtained and compared. In order to verify the different sensitivities, the field spatial harmonics in the two machines with and without considering the tolerances are further analyzed, from which the different origins of additional cogging torque components can be obtained. Finally, the IPM prototypes with and without amplified tolerances are fabricated and tested to verify the analyses. Autors: Xiao Ge;Z. Q. Zhu; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3557 - 3567 Publisher: IEEE
 Abstract:In this letter, we study optimal sensor selection for cooperative sensing in cognitive radio networks using a linear soft fusion approach. Our goal is to find a set of K sensors and its optimal linear combination rule that maximizes the expected system capacity of secondary users while meeting the requirement on the protection of primary transmission. We formulate the problem as a cardinality-constrained convex optimization problem and propose approximation algorithms that account for the effect of pathloss and correlated shadowing. Simulation results show that the proposed algorithms achieve comparable performance to the optimal solution. Autors: Jihyun Lee;Eylem Ekici; Appeared in: IEEE Communications Letters Publication date: Jul 2017, volume: 21, issue:7, pages: 1633 - 1636 Publisher: IEEE
» Sensorless Control of Permanent Magnet Synchronous Machine Based on Second-Order Sliding-Mode Observer With Online Resistance Estimation
 Abstract:In this paper, a supertwisting algorithm based second-order sliding-mode observer (STA-SMO) with online stator resistance () estimation for sensorless control of a nonsalient permanent magnet synchronous machine is proposed. A stator current observer is designed based on an STA to estimate the back electromotive force. A discontinuous sign function in the conventional SMO is replaced by a supertwisting function. The chattering problem, unavoidable in conventional SMO, is eliminated by reducing the amplitude of switching function of an STA-SMO. Meanwhile, a parallel online estimation scheme is presented based on a modified SMO. Because mismatch between actual and set resistance may lead to estimation error and even system instability. The Lyapunov stability theorem is used to obtain the stable conditions of the proposed online observer at both motoring and generating mode. With the help of online observer, resistance uncertainties caused by temperature variation can be taken into account, which means robustness and stability of an STA-SMO can be improved. At the same time, higher position and speed estimation accuracy is obtained and operation range of sensorless control is extended. Finally, the proposed method is validated and compared with a conventional method by simulations and experiments. Autors: Donglai Liang;Jian Li;Ronghai Qu; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3672 - 3682 Publisher: IEEE
» Sensorless Direct Flux Vector Control of Synchronous Reluctance Motors Including Standstill, MTPA, and Flux Weakening
 Abstract:This paper proposes a sensorless direct flux vector control scheme for synchronous reluctance motor drives. Torque is controlled at constant switching frequency, via the closed loop regulation of the stator flux linkage vector and of the current component in quadrature with it, using the stator flux oriented reference frame. A hybrid flux and position observer combines back-electromotive force (EMF) integration with pulsating voltage injection around zero speed. Around zero speed, the position observer takes advantage of injected pulsating voltage. Instead of the commonly used current demodulation, the position error feedback is extracted here at the output of the observer's flux maps, thus resulting in immunity toward the cross-saturation position error. The maximum torque per ampere (MTPA) strategy is used. A detailed analysis puts in evidence the key advantages and disadvantages related to the use of the MTPA in the sensorless control of the synchronous reluctance machine, for both the saliency-based and the back-EMF based sensorless methods. Extensive experimental results are reported for a 2.2 kW synchronous reluctance motor prototype, showing the feasibility of the proposed method. These include speed response to step and sinusoidal load disturbances at standstill, up to 121% of rated torque, and speed response tests covering the flux weakening speed region. Autors: Arzhang Yousefi-Talouki;Paolo Pescetto;Gianmario Pellegrino; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3598 - 3608 Publisher: IEEE
» Sequential Coordination of Transmission Expansion Planning With Strategic Generation Investments
 Abstract:This paper proposes mathematical models for sequential coordination of transmission expansion planning with strategic generation investments. The proactive and reactive coordinations are modeled and studied. The interaction between transmission company (Transco) and strategic generation companies (Gencos) is modeled using the sequential-move game. This is while the interaction between the strategic Gencos is modeled as a simultaneous-move game. In the proactive coordination, the Transco expands its future transmission capacities taking into account the strategic investments by Gencos. In the reactive coordination, strategic Gencos move first and expand their future generation capacities and then Transco expands the transmission capacity. The proactive coordination is modeled as a mixed-integer bilevel linear program (MIBLP) and the reactive coordination is modeled as a mixed-integer linear program (MILP). The MIBLP has binary variables in both upper and lower levels. The Moore–Bard algorithm is parallelized and used to solve the MIBLP. The mathematical models and the parallelized Moore–Bard algorithm are tested on 3-bus and 6-bus example systems and the modified IEEE-RTS96. Also, the IEEE 118-bus test system is studied using a heuristic version of the Moore–Bard algorithm. Autors: Yaser Tohidi;Mohammad Reza Hesamzadeh;Francois Regairaz; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2521 - 2534 Publisher: IEEE
» Sequential Decision Making With Coherent Risk
 Abstract:We provide sampling-based algorithms for optimization under a coherent-risk objective. The class of coherent-risk measures is widely accepted in finance and operations research, among other fields, and encompasses popular risk-measures such as conditional value at risk and mean-semi-deviation. Our approach is suitable for problems in which tuneable parameters control the distribution of the cost, such as in reinforcement learning or approximate dynamic programming with a parameterized policy. Such problems cannot be solved using previous approaches. We consider both static risk measures and time-consistent dynamic risk measures. For static risk measures, our approach is in the spirit of policy gradient methods, while for the dynamic risk measures, we use actor-critic type algorithms. Autors: Aviv Tamar;Yinlam Chow;Mohammad Ghavamzadeh;Shie Mannor; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3323 - 3338 Publisher: IEEE
» Sequential Deep Trajectory Descriptor for Action Recognition With Three-Stream CNN
 Abstract:Learning the spatial-temporal representation of motion information is crucial to human action recognition. Nevertheless, most of the existing features or descriptors cannot capture motion information effectively, especially for long-term motion. To address this problem, this paper proposes a long-term motion descriptor called sequential deep trajectory descriptor (sDTD). Specifically, we project dense trajectories into two-dimensional planes, and subsequently a CNN-RNN network is employed to learn an effective representation for long-term motion. Unlike the popular two-stream ConvNets, the sDTD stream is introduced into a three-stream framework so as to identify actions from a video sequence. Consequently, this three-stream framework can simultaneously capture static spatial features, short-term motion, and long-term motion in the video. Extensive experiments were conducted on three challenging datasets: KTH, HMDB51, and UCF101. Experimental results show that our method achieves state-of-the-art performance on the KTH and UCF101 datasets, and is comparable to the state-of-the-art methods on the HMDB51 dataset. Autors: Yemin Shi;Yonghong Tian;Yaowei Wang;Tiejun Huang; Appeared in: IEEE Transactions on Multimedia Publication date: Jul 2017, volume: 19, issue:7, pages: 1510 - 1520 Publisher: IEEE
» Sequential Detection for Cognitive Radio With Multiple Primary Transmit Power Levels
 Abstract:In this paper, we consider the sequential detection problem in a new cognitive radio scenario when the primary user (PU) works with more than one transmit power level. Different from most existing literature where PU is assumed to operate with a constant transmit power only, this new consideration well matches the practical standards, e.g., IEEE 802.11 Series, LTE, LTE-A, and so on, as well as the adaptive powering concept that a user would vary its transmit power under different situations. The targets of the secondary user here are not only to detect the presence of PU but also to recognize PU’s transmit power levels. We first formulate a valid sequential detection approach via the modified Neyman-Pearson criterion and then derive the closed-form decision region for each PU’s transmit power level. Many interesting discussions are raised. Moreover, the average sample number, a key metric for any sequential detection method, is derived in closed form to facilitate the performance evaluation. The performance comparison of the sequential detection and the fixed sample detection for this multiple primary transmit power levels scenario is analyzed. Finally, the simulation results are presented to verify the correctness of the proposed studies. Autors: Zan Li;Shuijun Cheng;Feifei Gao;Ying-Chang Liang; Appeared in: IEEE Transactions on Communications Publication date: Jul 2017, volume: 65, issue:7, pages: 2769 - 2780 Publisher: IEEE
» SER of TAS-MRC With Relay and User Selection in MIMO-Relay Systems Over Non-Identical Nakagami Fading Channels
 Abstract:We investigate the symbol error rate (SER) of a transmit antenna selection (TAS)-maximal ratio combining (MRC) with relay and user selection in multiple-input multiple-output systems over non-identical Nakagami fading channels. This letter derives the exact cumulative density function (cdf) of the effective signal-to-noise ratio for the proposed system. Using the cdf, this letter derives the exact closed-form expressions of the TAS-MRC with relay and user selection for the SER with M-ary quadrature amplitude modulation over non-identical Nakagami fading channels including quantification of the diversity order using asymptotic analysis. Autors: Donghun Lee; Appeared in: IEEE Communications Letters Publication date: Jul 2017, volume: 21, issue:7, pages: 1645 - 1648 Publisher: IEEE
» Service Provisioning and User Association for Heterogeneous Wireless Railway Networks
 Abstract:In addition to comforting passengers’ journey, the modern railway system is responsible to support a variety of on-board Internet services to meet the passenger’s demands on seamless service provisioning. In order to provide wireless access to the train, one idea attracting increasing attention is to deploy a series of track-side access points (TAPs) with high-speed data rates along the rail lines dedicated to the broadband mobile service provisioning on board. Due to the heavy data traffic flushing into the base stations (BSs) of the cellular networks, TAPs act as a complement to the BSs in data delivery. In this paper, we focus on the TAP association problem for service provisioning in a heterogeneous wireless railway network, where the TAP and BS coexist by applying a queueing game theoretic approach. Specifically, we present comprehensive theoretical analysis of the delay performance on the circumstances of partially observed, totally unobserved, and totally observed state of the system. Moreover, based on the considered payoff model and the derived association delay time, the passenger’s equilibrium strategies on association behaviors, i.e., whether to associate with a TAP or not, are studied. Finally, performance evaluations and discussions are provided to illustrate our proposed passenger-TAP association scheme for the heterogeneous wireless railway communication system. Autors: Yun Hu;Zheng Chang;Hongyan Li;Tapani Ristaniemi;Zhu Han; Appeared in: IEEE Transactions on Communications Publication date: Jul 2017, volume: 65, issue:7, pages: 3066 - 3078 Publisher: IEEE
» Service-Oriented Cooperation Models and Mechanisms for Heterogeneous Driverless Vehicles at Continuous Static Critical Sections
 Abstract:As driverless vehicles are increasingly becoming possible, so does the use of such vehicles as intelligent carriers in different domains. Intelligent transportation systems (ITSs) show increasingly heterogeneous, cyber-physical, cooperative, and service-oriented features and are beginning to be merged with the emerging cyber-physical-social systems. Given this new trend, how to make these intelligent vehicles cooperate more safely and efficiently with one another according to novel constraints, such as mission type and quality-of-service (QoS), has become a vital aspect of cooperative ITS (C-ITS). With these emerging characteristics, the classical passing-through-intersection problem has gained new connotations, worth further exploring. After analyzing the essences of this new problem, service-oriented cooperation models and mechanisms for whole autonomous vehicles approaching intersections are investigated in this paper. First, related traffic objects and possible vehicular behaviors are abstracted and modeled with the cyber-physical cooperative features and QoS constraints. A new reservation-based scheduling procedure is then conducted by employing the concepts of vehicle-to-infrastructure communication, and typical vehicular passing-through behaviors and several spatial-temporal constraints are designed to coordinate vehicles passing through an intersection divided as a series of continuous static critical sections. Given these considerations, a priority-based centralized scheduling algorithm, named csPriorFIFO, which adopts a novel priority inheritance mechanism to promote the traffic QoS of emergent vehicles, is proposed. Finally, all these designs are implemented in a traffic simulator named QoS-CITS, and the functions and the performance of these studied methods are verified and compared. Autors: Kailong Zhang;Ansheng Yang;Hang Su;Arnaud de La Fortelle;Kejian Miao;Yuan Yao; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Jul 2017, volume: 18, issue:7, pages: 1867 - 1881 Publisher: IEEE
» Setting Cosplay in Motion
 Abstract:Art and engineering have always gone hand in hand. That which is purely functional is largely displeasing-if not also delightful-to look at. After all, we have cars and appliances that come in all shapes and colors. It is why we have architecture and not simply square boxes for buildings. This relationship has continued into many aspects of both art and engineering, and for me that aspect is cosplay. Autors: Christine Marchese; Appeared in: IEEE Potentials Publication date: Jul 2017, volume: 36, issue:4, pages: 44 - 46 Publisher: IEEE
» Sharing-Aware Online Virtual Machine Packing in Heterogeneous Resource Clouds
 Abstract:One of the key problems that cloud providers need to efficiently solve when offering on-demand virtual machine (VM) instances to a large number of users is the VM Packing problem, a variant of Bin Packing. The VM Packing problem requires determining the assignment of user requested VM instances to physical servers such that the number of physical servers is minimized. In this paper, we consider a more general variant of the VM Packing problem, called the Sharing-Aware VM Packing problem, that has the same objective as the standard VM Packing problem, but allows the VM instances collocated on the same physical server to share memory pages, thus reducing the amount of cloud resources required to satisfy the users’ demand. Our main contributions consist of designing several online algorithms for solving the Sharing-Aware VM Packing problem, and performing an extensive set of experiments to compare their performance against that of several existing sharing-oblivious online algorithms. For small problem instances, we also compare the performance of the proposed online algorithms against the optimal solution obtained by solving the offline variant of the Sharing-Aware VM Packing problem (i.e., the version of the problem that assumes that the set of VM requests are known a priori). The experimental results show that our proposed sharing-aware online algorithms activate a smaller average number of physical servers relative to the sharing-oblivious algorithms, directly reduce the amount of required memory, and thus, require fewer physical servers to instantiate the VM instances requested by users. Autors: Safraz Rampersaud;Daniel Grosu; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Jul 2017, volume: 28, issue:7, pages: 2046 - 2059 Publisher: IEEE
» Short-Range Wireless Localization Based on Meta-Aperture Assisted Compressed Sensing
 Abstract:Wireless localization has become a hot topic in the area of microwave engineering. In this paper, we propose a new approach for short-range wireless localization based on meta-aperture and compressed sensing (CS). Utilizing the plasmonic dispersion of a magnetically uniaxial metamaterial, a pushpin-shaped autocorrelation characteristic of the localization system can be obtained to ensure high localization precision. Compared with existing realizations based on traveling wave excited, randomly arranged subwavelength resonant elements, our method uses a homogeneous aperture for the generation of randomized illumination. Based on the CS, localization can be obtained with much less data and much faster data processing than conventional methods. Simulation and experimental investigation are conducted, and the results demonstrate the effectiveness of the proposed approach. With the simple implementation for fast localization, our method has promising potential in practical applications. Autors: Tianyi Zhou;Huan Li;Dexin Ye;Jiangtao Huangfu;Shan Qiao;Yongzhi Sun;Weiqiang Zhu;Changzhi Li;Lixin Ran; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Jul 2017, volume: 65, issue:7, pages: 2516 - 2524 Publisher: IEEE
» Short-Term Electricity Price Forecasting With Stacked Denoising Autoencoders
 Abstract:A short-term forecasting of the electricity price with data-driven algorithms is studied in this research. A stacked denoising autoencoder (SDA) model, a class of deep neural networks, and its extended version are utilized to forecast the electricity price hourly. Data collected in Nebraska, Arkansas, Louisiana, Texas, and Indiana hubs in U.S. are utilized. Two types of forecasting, the online hourly forecasting and day-ahead hourly forecasting, are examined. In online forecasting, SDA models are compared with data-driven approaches including the classical neural networks, support vector machine, multivariate adaptive regression splines, and least absolute shrinkage and selection operator. In the day-ahead forecasting, the effectiveness of SDA models is further validated through comparing with industrial results and a recently reported method. Computational results demonstrate that SDA models are capable to accurately forecast electricity prices and the extended SDA model further improves the forecasting performance. Autors: Long Wang;Zijun Zhang;Jieqiu Chen; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2673 - 2681 Publisher: IEEE
» Short-Term Relaxation in HfOx/CeOx Resistive Random Access Memory With Selector
 Abstract:This letter illustrates short-term relaxation in CeOx-based resistive random access memory (RRAM) devices. Our results suggest that the noise of the serial selector device can impact the short-term relaxation, reduce the operating window of the RRAM, and increase the read error. Our findings indicate that the application of longer initial forming pulses can mitigate the short-term relaxation issue. Autors: Cheng-Chih Hsieh;Yao-Feng Chang;Yoocharn Jeon;Anupam Roy;Davood Shahrjerdi;Sanjay K. Banerjee; Appeared in: IEEE Electron Device Letters Publication date: Jul 2017, volume: 38, issue:7, pages: 871 - 874 Publisher: IEEE
» SIFTing Through Scales
 Abstract:Scale invariant feature detectors often find stable scales in only a few image pixels. Consequently, methods for feature matching typically choose one of two extreme options: matching a sparse set of scale invariant features, or dense matching using arbitrary scales. In this paper, we turn our attention to the overwhelming majority of pixels, those where stable scales are not found by standard techniques. We ask, is scale-selection necessary for these pixels, when dense, scale-invariant matching is required and if so, how can it be achieved? We make the following contributions: (i) We show that features computed over different scales, even in low-contrast areas, can be different and selecting a single scale, arbitrarily or otherwise, may lead to poor matches when the images have different scales. (ii) We show that representing each pixel as a set of SIFTs, extracted at multiple scales, allows for far better matches than single-scale descriptors, but at a computational price. Finally, (iii) we demonstrate that each such set may be accurately represented by a low-dimensional, linear subspace. A subspace-to-point mapping may further be used to produce a novel descriptor representation, the Scale-Less SIFT (SLS), as an alternative to single-scale descriptors. These claims are verified by quantitative and qualitative tests, demonstrating significant improvements over existing methods. A preliminary version of this work appeared in [1] . Autors: Tal Hassner;Shay Filosof;Viki Mayzels;Lihi Zelnik-Manor; Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence Publication date: Jul 2017, volume: 39, issue:7, pages: 1431 - 1443 Publisher: IEEE
» Signature Analysis for Online Motor Diagnostics: Early Detection of Rotating Machine Problems Prior to Failure
 Abstract:The Stator-current signature analysis of induction motors is a proven method to diagnose rotor squirrel-cage winding defects and air-gap-eccentricity problems. With this technology, specific frequency-current components can be identified as an indication of cage-winding defects as well as a nonuniform gap between the stator and rotor. Since these data are generally collected periodically, it is important to identify the components as early as possible. The trendable parameters can then be monitored more often to avoid in-service failure. With the application of new processing technologies, the ability to identify these critical current-signature frequency components and trend the deterioration that they indicate has improved. This allows for maintenance activities to be scheduled earlier and performed prior to failure, avoiding costly motor component damage and unplanned downtime. Autors: Ian Culbert;John Letal; Appeared in: IEEE Industry Applications Magazine Publication date: Jul 2017, volume: 23, issue:4, pages: 76 - 81 Publisher: IEEE
» Silicon valley's latest craze: brain tech [News]
 Abstract:Silicon Valley's biggest inf luencers want to get inside your head. Over the past year, four leading figures have announced plans to make gadgets that will either nestle into the fleshy folds of your brain or sit atop your head to read your thoughts from the outside. Autors: Eliza Strickland; Appeared in: IEEE Spectrum Publication date: Jul 2017, volume: 54, issue:7, pages: 8 - 9 Publisher: IEEE
» Silicon-Based SERS Substrates Fabricated by Electroless Etching
 Abstract:Surface enhanced Raman scattering has recently been proposed as a label free sensing method for diagnostic applications. Raman scattering is an excellent analysis tool because a wealth of information can be obtained using a single measurement, however the weak signal has made it unsuitable for detecting low concentrations of analytes. Using plasmonic nanostructures to create SERS substrates, the Raman signal can be amplified by several orders of magnitude, but SERS substrates have been complicated to fabricate. Here we report low-cost silicon substrates based on simple fabrication method of silver nanoparticles and silicon nanowires decorated with these nanoparticles for use as a convenient practical platform for SERS-active substrates. In addition, the placement of silver nanoparticles on silicon nanowires allowed the autoaligning of the hot spots such that low cost Raman systems with normal incident laser can be used. These substrates have the ability to detect wide range of concentrations of pyridine, as low as 10 –11 M. An enhancement factor of around 6 to 8 × 105 was observed for silver nanoparticles alone. By depositing the same nanoparticles on silicon nanowires, the enhancement factor jumped by orders of magnitude to 1011. Autors: Mohamed Y. Elsayed;Abdelaziz M. Gouda;Yehea Ismail;Mohamed A. Swillam; Appeared in: Journal of Lightwave Technology Publication date: Jul 2017, volume: 35, issue:14, pages: 3075 - 3081 Publisher: IEEE
» Simplified Erasure/List Decoding
 Abstract:It was previously shown by Hashimoto that Forney’s optimal erasure decoder can be significantly simplified, in the sense that a simplified decoder achieves the same random coding bounds, for the ensemble of independent and identically distributed codewords. In this paper, the analysis of simplified decoders is refined and generalized in several aspects. First, tighter random coding bounds for simplified decoders are derived, which equal the exact exponential behavior of the fixed composition ensemble average. Second, the exponential bounds are valid both in the erasure mode and in the list mode. Third, the analysis pertains to a rather general class of simplified decoders, including the case of mismatch in the threshold function of the decoder. Fourth, expurgated exponents, which are larger than the random coding exponents at low rates, are shown to be achievable using a significantly simpler decoder than Forney’s optimal decoder. It is shown numerically that, from the aspect of exact random coding exponents, a decoder in the spirit of Hashimoto’s is as good as Forney’s in the erasure mode, as well as in the list mode. Autors: Nir Weinberger;Neri Merhav; Appeared in: IEEE Transactions on Information Theory Publication date: Jul 2017, volume: 63, issue:7, pages: 4218 - 4239 Publisher: IEEE
» Simulation and Ship Detection Using Surface Radial Current Observing Compact HF Radar
 Abstract:This paper proposes an effective method of improving ship detection performance of a compact high-frequency (HF) radar system which has been primarily optimized for observing surface radial current velocities and bearings. Previously developed ship detection systems have been vulnerable to error sources such as environmental noise and clutter when they are applied in a compact HF radar optimized for observing surface current. In particular, the influences of error are reduced by applying a principle component analysis of the generated range-Doppler maps. A compact radar signal model is first developed by the data acquired from an operating compact HF radar site. The proposed method is then validated by comparing it to the conventional ship detection method in terms of detection and false alarm rates. The experimental results confirm that the proposed method shows superior performance in both simulated and practical environments. Autors: Sangwook Park;Chul Jin Cho;Bonhwa Ku;SangHo Lee;Hanseok Ko; Appeared in: IEEE Journal of Oceanic Engineering Publication date: Jul 2017, volume: 42, issue:3, pages: 544 - 555 Publisher: IEEE
» Simulation of Electronic DNA Sequencing Based on Intrinsic Molecular Charges
 Abstract:We model and simulate the use of ion sensitive field-effect transistor for electronic deoxyribonucleic acid (DNA) sequencing using its intrinsic molecular charge on the backbone. In this model, biological layer is treated as an ion-permeable charged membrane in solving Poisson equation. Sensor I–V characteristics are simulated, showing that the shifts of device threshold voltage respond to the DNA base-extension reaction. The simulation reveals the effects of DNA surface density, the length of a single-stranded DNA, and salt concentration on sensor performance. The simulation results demonstrate good agreement with the published experimental data, therefore, could be a good guide to actual biosensor design and fabrication. Autors: Yang Liu;Yuchen Liang;Walter Hu;Dian Zhou;Ran Liu;Jun Tao;Xuan Zeng; Appeared in: IEEE Transactions on Nanotechnology Publication date: Jul 2017, volume: 16, issue:4, pages: 711 - 720 Publisher: IEEE

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