Electrical and Electronics Engineering publications abstract of: 03-2017 sorted by title, page: 16

» Sensorless Frequency and Voltage Control in the Stand-Alone DFIG-DC System
Abstract:
A sensorless stand-alone control scheme of a doubly fed induction generator (DFIG)-DC system is investigated in this paper. In this layout, the stator voltage is rectified by a diode bridge that is directly connected to a dc bus. The rotor-side voltage source inverter is the only controlled converter required in this system and is directly powered by the same dc bus created by the stator-side rectifier. DC voltage and stator frequency are regulated by two independent proportional-integral regulators that give the references for inner current controllers implementing field-oriented control. As it is capable of creating a stable and regulated dc bus, this system can be conveniently adopted to supply dc loads or to form a dc grid. Due to the constraint imposed by the stator diode bridge, the DFIG has to operate under a constant stator voltage, and the conventional stator field-oriented control implemented in stand-alone ac DFIG must be modified. This paper presents the control structure and the theoretical framework for the controller synthesis. Simulation and experimental validations on a small-scale rig are included.
Autors: Gil D. Marques;Matteo F. Iacchetti;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 1949 - 1957
Publisher: IEEE
 
» Sequential Detector Design for Spectrum Sensing Considering Instantaneously Nonidentically Distributed Samples
Abstract:
This paper studies signal detection methods in cognitive radios based on both the well-known likelihood ratio test (LRT) and the sequential probability ratio test (SPRT) considering instantaneously nonidentically distributed samples. Since it is rather impractical to perform the ideal test that fully reflects such a change of a sample statistic, we used a practical detection method that optimally approximates the ideal log-likelihood ratio with respect to its statistical mean. In the LRT scenario, we found that there exists a nonnegligible performance gap between the ideal and practical tests, and the related experiments and theoretical analyses are also explored. Furthermore, we propose how to design a sequential detector in a robust manner to guarantee predefined false-alarm and missed-detection constraints for both the ideal and practical SPRTs.
Autors: Yeon-Jea Cho;Dong-Jo Park;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2158 - 2169
Publisher: IEEE
 
» Series Compensator Based on Cascaded Transformers Coupled With Three-Phase Bridge Converters
Abstract:
This paper proposes a multilevel series compensator (MSC) to deal with voltage sags/swells, harmonic compensation, or reactive power compensation. Such a device can be considered as a dynamic voltage restorer or a series active power filter (Series-APF). The MSC can improve the power quality of loads located in stiff systems. The configuration is based on three-phase bridge (TPB) converters connected by means of cascaded single-phase transformers. This arrangement permits the use of a single dc-link. A generalization for -stages in which -transformers are coupled with -TPB converters is presented. The topology permits generating a high number of levels in the voltage waveforms with a low number of power switches in comparison with a classic topology. The multilevel waveforms are generated by the converters through a suitable pulsewidth modulation (PWM) strategy that takes into consideration the transformer turns ratios. Modularity and simple maintenance make the proposed MSC an attractive solution compared with some conventional configurations. Model, PWM strategy, and overall control are discussed in this paper. Simulation and experimental results are presented as well.
Autors: Gregory Arthur de Almeida Carlos;Cursino Brandão Jacobina;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 1271 - 1279
Publisher: IEEE
 
» Service Curve Estimation-Based Characterization and Evaluation of Closed-Loop Flow Control
Abstract:
Closed-loop flow control protocols, such as the prominent implementation transmission control protocol (TCP), are prevalent in the Internet, today. TCP has continuously been improved for greedy traffic sources to achieve high throughput over networks with large bandwidth delay products. Recently, the increasing use for streaming and interactive applications, such as voice and video, has shifted the focus toward its delay performance. Given the need for real-time communication of non-greedy sources via TCP, we present an estimation method for performance evaluation of closed-loop flow control protocols. We characterize an end-to-end connection by a service curve that provides statistical guarantees for arbitrary traffic. The estimation is based on end-to-end measurements at the application level that include all effects induced by the network and by the protocol stacks of the end systems. From our measurements, we identify different causes for delays. We show that significant delays are due to queueing in protocol stacks. Notably, this occurs even if the utilization is moderate. Using our estimation method, we compare the impact of fundamental mechanisms of TCP on delays at the application level: in detail, we analyze parameters relevant for network dimensioning, including buffer provisioning and active queue management, and parameters for server configuration, such as the congestion control algorithm. By applying our method as a benchmark, we find that a good selection can largely improve the delay performance of TCP.
Autors: Ralf Lübben;Markus Fidler;
Appeared in: IEEE Transactions on Network and Service Management
Publication date: Mar 2017, volume: 14, issue:1, pages: 161 - 175
Publisher: IEEE
 
» Seven-bit 700-MS/s Four-Way Time-Interleaved SAR ADC With Partial $V_{mathrm {cm}}$ -Based Switching
Abstract:
This brief presents a 7-bit 700-MS/s four-way time-interleaved successive approximation register (SAR) analog-to-digital converter (ADC). A partial -based switching method is proposed that requires less digital overhead from the SAR controller and achieves better conversion accuracy. Compared with switchback switching, the proposed method can further reduce the common mode variation by 50%. In addition, the impacts of such a reduction on the comparator offset, noise, and input parasitic are theoretically analyzed and verified by simulation. The prototype fabricated in a 65-nm CMOS technology occupies an active area of 0.025 mm2. The measurement results at the 700 MS/s sampling rate show that the ADC achieves signal-to-noise-and-distortion ratio of 40 dB at Nyquist input and consumes 2.72 mW from a 1.2 V supply, which results in a Walden FoM of 48 fJ/conversion step.
Autors: Dezhi Xing;Yan Zhu;Chi-Hang Chan;Sai-Weng Sin;Fan Ye;Junyan Ren;Seng-Pan U;Rui Paulo Martins;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Mar 2017, volume: 25, issue:3, pages: 1168 - 1172
Publisher: IEEE
 
» Shape Estimation from Shading, Defocus, and Correspondence Using Light-Field Angular Coherence
Abstract:
Light-field cameras are quickly becoming commodity items, with consumer and industrial applications. They capture many nearby views simultaneously using a single image with a micro-lens array, thereby providing a wealth of cues for depth recovery: defocus, correspondence, and shading. In particular, apart from conventional image shading, one can refocus images after acquisition, and shift one's viewpoint within the sub-apertures of the main lens, effectively obtaining multiple views. We present a principled algorithm for dense depth estimation that combines defocus and correspondence metrics. We then extend our analysis to the additional cue of shading, using it to refine fine details in the shape. By exploiting an all-in-focus image, in which pixels are expected to exhibit angular coherence, we define an optimization framework that integrates photo consistency, depth consistency, and shading consistency. We show that combining all three sources of information: defocus, correspondence, and shading, outperforms state-of-the-art light-field depth estimation algorithms in multiple scenarios.
Autors: Michael W. Tao;Pratul P. Srinivasan;Sunil Hadap;Szymon Rusinkiewicz;Jitendra Malik;Ravi Ramamoorthi;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Mar 2017, volume: 39, issue:3, pages: 546 - 560
Publisher: IEEE
 
» Shape-Based Building Detection in Visible Band Images Using Shadow Information
Abstract:
This paper introduces a novel methodology for automated detection of buildings from single high-resolution optical images with only visible red, green, and blue bands of data. In particular, we first investigate the shadow evidence to focus on building regions. Then, a novel Markov random field (MRF)-based region growing segmentation technique is proposed. Image is oversegmented into smaller homogeneous regions that can be used to replace the rigid structure of the pixel grid. An iterative classification merging is then applied over this set of regions. At each iteration, regions are classified using a region-level MRF model, then, according to the position of shadows, regions having the same class are merged to produce new regions whose shapes are appropriate to rectangles. The final buildings are determined using a recursive minimum bounding rectangle. The experimental results prove that the proposed method is applicable in various areas (high dense urban, suburban, and rural) and is highly robust and reliable.
Autors: Tran-Thanh Ngo;Vincent Mazet;Christophe Collet;Paul de Fraipont;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Mar 2017, volume: 10, issue:3, pages: 920 - 932
Publisher: IEEE
 
» Shaping Diverted Plasmas With Symplectic Maps
Abstract:
We construct an area preserving and integrable map to represent magnetic surfaces with triangularity in single-null divertor tokamaks. The magnetic surfaces obtained by the map can assume different asymmetric geometries and the position of X-point, through the choices of values for some free parameters. The safety factor profile is independent of the geometric parameters and can also be chosen arbitrarily. We combine the divertor integrable map with a nonintegrable map that simulates the effect of external magnetostatic perturbations. The application of this methodology permits to obtain the escape patterns of magnetic field lines on the divertor plates.
Autors: Geraldo Roberson;Marisa Roberto;Iberê Luiz Caldas;Tiago Kroetz;Ricardo Luiz Viana;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Mar 2017, volume: 45, issue:3, pages: 356 - 363
Publisher: IEEE
 
» Shift Factor-Based SCOPF Topology Control MIP Formulations With Substation Configurations
Abstract:
Topology control (TC) is an effective tool for managing congestion, contingency events, and overload control. The majority of TC research has focused on line and transformer switching. Substation reconfiguration is an additional TC action, which consists of opening or closing breakers not in series with lines or transformers. Some reconfiguration actions can be simpler to implement than branch opening, seen as a less invasive action. This paper introduces two formulations that incorporate substation reconfiguration with branch opening in a unified TC framework. The first method starts from a topology with all candidate breakers open, and breaker closing is emulated and optimized using virtual transactions. The second method takes the opposite approach, starting from a fully closed topology and optimizing breaker openings. We provide a theoretical framework for both methods and formulate security-constrained shift factor MIP TC formulations that incorporate both breaker and branch switching. By maintaining the shift factor formulation, we take advantage of its compactness, especially in the context of contingency constraints, and by focusing on reconfiguring substations, we hope to provide system operators additional flexibility in their TC decision processes. Simulation results on a subarea of PJM illustrate the application of the two formulations to realistic systems.
Autors: Evgeniy A. Goldis;Pablo A. Ruiz;Michael C. Caramanis;Xiaoguang Li;C. Russ Philbrick;Aleksandr M. Rudkevich;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1179 - 1190
Publisher: IEEE
 
» Short Read Mapping: An Algorithmic Tour
Abstract:
Ultra-high-throughput next-generation sequencing (NGS) technology allows us to determine the sequence of nucleotides of many millions of DNA molecules in parallel. Accompanied by a dramatic reduction in cost since its introduction in 2004, NGS technology has provided a new way of addressing a wide range of biological and biomedical questions, from the study of human genetic disease to the analysis of gene expression, protein–DNA interactions, and patterns of DNA methylation. The data generated by NGS instruments comprise huge numbers of very short DNA sequences, or “reads,” that carry little information by themselves. These reads therefore have to be pieced together by well-engineered algorithms to reconstruct biologically meaningful measurements, such as the level of expression of a gene. To solve this complex, high-dimensional puzzle, reads must be mapped back to a reference genome to determine their origin. Due to sequencing errors and to genuine differences between the reference genome and the individual being sequenced, this mapping process must be tolerant of mismatches, insertions, and deletions. Although optimal alignment algorithms to solve this problem have long been available, the practical requirements of aligning hundreds of millions of short reads to the 3-billion-base-pair-long human genome have stimulated the development of new, more efficient methods, which today are used routinely throughout the world for the analysis of NGS data.
Autors: Stefan Canzar;Steven L. Salzberg;
Appeared in: Proceedings of the IEEE
Publication date: Mar 2017, volume: 105, issue:3, pages: 436 - 458
Publisher: IEEE
 
» Short-Frequency Fourier Transform for Fault Diagnosis of Induction Machines Working in Transient Regime
Abstract:
Transient-based methods for fault diagnosis of induction machines (IMs) are attracting a rising interest, due to their reliability and ability to adapt to a wide range of IM’s working conditions. These methods compute the time–frequency (TF) distribution of the stator current, where the patterns of the related fault components can be detected. A significant amount of recent proposals in this field have focused on improving the resolution of the TF distributions, allowing a better discrimination and identification of fault harmonic components. Nevertheless, as the resolution improves, computational requirements (power computing and memory) greatly increase, restricting its implementation in low-cost devices for performing on-line fault diagnosis. To address these drawbacks, in this paper, the use of the short-frequency Fourier transform (SFFT) for fault diagnosis of induction machines working under transient regimes is proposed. The SFFT not only keeps the resolution of traditional techniques, such as the short-time Fourier transform, but also achieves a drastic reduction of computing time and memory resources, making this proposal suitable for on-line fault diagnosis. This method is theoretically introduced and experimentally validated using a laboratory test bench.
Autors: Jordi Burriel-Valencia;Ruben Puche-Panadero;Javier Martinez-Roman;Angel Sapena-Bano;Manuel Pineda-Sanchez;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Mar 2017, volume: 66, issue:3, pages: 432 - 440
Publisher: IEEE
 
» Shortest Link Scheduling Algorithms in Wireless Networks Under the SINR Model
Abstract:
This paper considers the shortest link scheduling problem in wireless networks under the signal-to-interference-plus-noise ratio (SINR) model. We propose an -approximation algorithm called shortest link scheduling with power control (SLSPC) with oblivious power assignment and an -approximation algorithm called shortest link scheduling with uniform or mean power assignment (SLSUM) with uniform or mean power control, where is a constant serving as a regulatory factor for slight transmit power adjustment, and where and denote the lengths of the longest and shortest links, respectively. We conduct a rigorous theoretical performance analysis to analyze the feasibility and approximation factors of the proposed algorithms. We also carry out an extensive comparison-based simulation study, whose results indicate that the performances of SLSPC and SLSUM are superior over the state of the art as the set of the so-called “black and gray” links, which are difficult to schedule and should be sequentially scheduled, is completely removed by adjusting the transmit power appropriately via . Our numerical analysis demonstrates that the approximation ratios of our algorithms are tighter than the best known ratios.
Autors: Jiguo Yu;Baogui Huang;Xiuzhen Cheng;Mohammed Atiquzzaman;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2643 - 2657
Publisher: IEEE
 
» Signal Constellations Based on Eisenstein Integers for Generalized Spatial Modulation
Abstract:
This letter introduces signal constellations based on multiplicative groups of Eisenstein integers, i.e., hexagonal lattices. These sets of Eisenstein integers are proposed as signal constellations for generalized spatial modulation. The algebraic properties of the new constellations are investigated and a set partitioning technique is developed. This technique can be used to design coded modulation schemes over hexagonal lattices.
Autors: Jürgen Freudenberger;Sergo Shavgulidze;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 556 - 559
Publisher: IEEE
 
» Signal Processing Challenges in Cellular-Assisted Vehicular Communications: Efforts and developments within 3GPP LTE and beyond
Abstract:
Vehicular communications is an important enabler for enhancing the safety on roads by supporting mutual awareness of vehicles as well as for improving the efficiency of transportation through smart traffic management by intelligent transport systems (ITSs). Governments around the world have set ambitious goals for road fatality reduction in the near future; e.g., the European Union targets a 50% reduction of road fatalities by 2020 as compared to the year 2010. Furthermore, traffic telematic systems aim to minimize the environmental impact of transportation and maximize the utilization of available road infrastructure by adaptive traffic management. To realize these challenging targets, autonomous wireless information exchange among vehicles-vehicle to vehicle (V2V)-and with roadside infrastructure-vehicle to infrastructure (V2I)-are central ingredients. In addition to traffic efficiency and safetyrelated issues, vehicular communications is increasingly recognized as an important revenue driver by car manufacturing companies since it enables wirelessly connected in-vehicle entertainment systems that support on-demand video streaming and online Internet access for passengers. Also, in the future, machine-type communication is expected to play a major role in vehicular environments, with more sensors that monitor the internal state of vehicles and autonomously exchange service and maintenance information with cloud servers of manufacturers. Depending on the considered use-case, distinct quality of service (QoS) requirements come into play [1]: infotainment applications for in-car users require high bandwidth and network capacity, active road safety relies on delay- and outage-critical data transmission, whereas information exchange for road traffic efficiency management typically comes without strict QoS requirements and exhibits graceful degradation of performance with increasing latency.
Autors: Stefan Schwarz;Tal Philosof;Markus Rupp;
Appeared in: IEEE Signal Processing Magazine
Publication date: Mar 2017, volume: 34, issue:2, pages: 47 - 59
Publisher: IEEE
 
» Signal Processing for Smart Vehicle Technologies: Part 2 [From the Guest Editors]
Abstract:
Autors: John H.L. Hansen;Kazuya Takeda;Sanjeev M. Naik;Mohan M. Trivedi;Gerhard U. Schmidt;Yingying Jennifer Chen;Wade Trappe;
Appeared in: IEEE Signal Processing Magazine
Publication date: Mar 2017, volume: 34, issue:2, pages: 18 - 21
Publisher: IEEE
 
» Signaling Design of Two-Way MIMO Full-Duplex Channel: Optimality Under Imperfect Transmit Front-End Chain
Abstract:
We derive the optimal signaling for a multiple input multiple output (MIMO) full-duplex (FD) two-way channel under imperfect transmit front-end chains. We characterize two-way rates of the channel by using a game-theoretical approach, where we focus on the Pareto boundary of the achievable rate region and the Nash equilibrium (NE). For a MIMO FD channel, the Pareto boundary achieves the global optimality. However, deriving the Pareto boundary amounts to solving a family of centralized non-convex problems. By introducing auxiliary variables, we decouple and convert the Pareto boundary into a family of convex problems, which enables us to obtain the Pareto boundary with low computational complexity. In a MISO FD two-way channel, we further present a closed-form expression for the Pareto-optimal signaling. In our numerical examples, we quantify gains in the achievable rates of the Pareto-optimal signaling over the zero-forcing beamforming and NE. For a distributed MIMO FD channel, we establish the existence of NE and present a condition for the uniqueness of NE. We then propose an iterative water-filling algorithm, which is capable of reaching the NE. Through simulations, the threshold of the self-interference level is found below which the FD NE outperforms the half-duplex TDMA.
Autors: Shuqiao Jia;Behnaam Aazhang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Mar 2017, volume: 16, issue:3, pages: 1619 - 1632
Publisher: IEEE
 
» Silicon Thyristors for Ultrahigh Power (GW) Applications
Abstract:
Evolution of thyristor technology and the design concepts, which brought and maintain the phase control thyristor (PCT) at the top of a power pyramid, are discussed. The state-of-the-art device concepts like electrically triggered thyristor and light triggered thyristor are described for voltage classes up to 8.5 kV and maximal on-state rated current of 6 kA. Main focus is laid on the PCTs for high-voltage direct current transmission, the enabler of power transmission beyond the 10-GW level.
Autors: Jan Vobecký;Hans-Joachim Schulze;Peter Streit;Franz-Josef Niedernostheide;Virgiliu Botan;Jens Przybilla;Uwe Kellner-Werdehausen;M. Bellini;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 760 - 768
Publisher: IEEE
 
» Simulation of Mass Sensor Based on Luminescence of Micro/Nano Electromechanical Resonator
Abstract:
We report a novel mass sensor based on detecting the luminescence from micro/nano electromechanical resonators. Multi-physics simulation has been conducted to elucidate this concept. It is found that the added mass affects both the resonant frequency and oscillating amplitude of the mechanical resonator. However, we mainly use the change of oscillating amplitude to detect the added mass by observing varied optical intensity. For the device simulated, the sensitivity ( per microgram) is 2% if using frequency measurement through electronic circuits, while the sensitivity ( per microgram) is 377% using amplitude measurement through the proposed optical method.
Autors: Lijie Li;
Appeared in: IEEE Electron Device Letters
Publication date: Mar 2017, volume: 38, issue:3, pages: 395 - 398
Publisher: IEEE
 
» Simulation Study of Large-Scale Charge Sharing Mitigation Using Seamless Guard Band
Abstract:
In this paper, a novel seamless guard band (SGB) technique for charge sharing mitigation is studied using 3-D TCAD numerical simulations. The simulations results in 65-nm twin-well bulk CMOS technology indicate that the SGB technique can not only mitigate the single-event transient pulsewidth greatly but also mitigate the charge sharing between logical nodes or logical cells significantly. The simulation results also indicate that the SGB technique is superior to the conventional guard band (GB) technique, for it is more beneficial for parasitic bipolar effect mitigation. Using SGB technique, the single-event double-transient (SEDT) generation is mitigated completely under low LET particle (LET ) radiation, and the SEDT pulsewidth is mitigated > 50% even with the LET of 80 , which is > 25% from GB technique. Finally, the SGB technique can be applied to the construction of a radiation-hardened standard cell library conveniently, and its area penalty is 1–1.67 , which is the same with that of the GB technique.
Autors: Pengcheng Huang;Shuming Chen;Jianjun Chen;Liang Bin;Zhenyu Wu;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Mar 2017, volume: 17, issue:1, pages: 176 - 183
Publisher: IEEE
 
» Simulation-Based Study About the Lifetime and Incident Light Properties Dependence of the Optically Triggered 4H-SiC Thyristors Operation
Abstract:
We investigated a methodology to design light-triggered thyristors thanks to TCAD. The simulation model accuracy, especially the holding current and the minimum incident light intensity to turn-ON, were compared with experimental results. The influence of SiC epitaxial layer lifetime and the incident light properties (wavelength and intensity) on the optically triggered 4H-SiC thyristor characteristics have been studied by simulation. We considered the wavelength dependence of quantum efficiency, penetration depth, and photon energy. The holding current and turn-ON time depends on the lifetime. The minimum intensity to turn-ON the device significantly depends on the wavelength. This intensity becomes less than 0.003 times when the wavelength changed from 380 to 325 nm. In addition, the breakover voltage is affected by the constant incident light even if the intensity is tiny.
Autors: Junichi Hasegawa;Loris Pace;Luong Viêt Phung;Mutsuko Hatano;Dominique Planson;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 1203 - 1208
Publisher: IEEE
 
» Simultaneous Echo Power and Doppler Frequency Measurement System Based on Microwave Photonics Technology
Abstract:
A Doppler shift measurement system based on four-wave mixing effect in a highly nonlinear fiber is demonstrated practically. The system exhibits two low-frequency voltages, which are functions of the Doppler shift, and therefore, low-cost low-frequency photodetectors can be employed in the system. No sophisticated electrical instrument is required to perform the measurement. The scheme is able to simultaneously and independently measure the Doppler frequency of a radar echo and its power level with carrier frequency up to 40 GHz. The system is suitable to be employed in any microwave photonics (MWP) radar system with broad frequency agility characteristics or the other MWP systems operating based on frequency hopping technique.
Autors: Hossein Emami;Mohammadreza Hajihashemi;Sayed Ehsan Alavi;Mohammad Ghanbarisabagh;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Mar 2017, volume: 66, issue:3, pages: 508 - 513
Publisher: IEEE
 
» Simultaneous Vehicle Real-Time Longitudinal and Lateral Velocity Estimation
Abstract:
Accurate information on vehicle longitudinal and lateral velocities is vital for the efficient operation of many vehicle control systems. In this paper, an estimation structure to simultaneously estimate vehicle velocities in longitudinal and lateral directions is developed and experimentally validated. This structure includes two parallel estimators: The first estimator is a kinematic-based observer for longitudinal velocity estimation, and the second is a combination of a kinematic-based observer and an inverse tire model to estimate vehicle lateral velocity. The proposed structure can effectively handle the additive biases, which are common in a vehicle's stock accelerometers' signals, and provide an accurate estimate of vehicle velocities when one (or more than one) wheel experiences excessive slippage. Additionally, the proposed structure is not sensitive to changes in parameters of the tire model and vehicle mass. The performance of this estimation structure is validated by experimental studies.
Autors: A. Rezaeian;A. Khajepour;W. Melek;S.-Ken Chen;N. Moshchuk;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 1950 - 1962
Publisher: IEEE
 
» Simultaneous Wireless Transfer of Power and Information in a Decode-and-Forward Two-Way Relaying Network
Abstract:
We consider a simultaneous wireless transfer of information and power in a two-way relaying network, where a decode-and-forward protocol is employed for data exchange between two source devices at different rates. The data exchange is accomplished in two time phases (TPs) with possibly asymmetric TP ratios, where the relay is powered by the source devices in the first phase through simultaneous wireless information and power transfer (SWIPT) either by power splitting (PS) or by time switching (TS). For the network, resource allocation of the PS and TP ratios for the PS-based SWIPT and that of the TS and TP ratios for the TS-based SWIPT are studied to minimize the system outage probability. We first solve the joint optimization problem of each case with the instantaneous channel state information and then propose suboptimal schemes utilizing one or two values for the TP ratio to lower the implementation complexity. The results from analysis and simulation show that the proposed schemes outperform the benchmark scheme with equal resource allocation and that the gain gets more prominent as the rates of the data exchanged or the relay locations become more asymmetric.
Autors: Thinh Phu Do;Iickho Song;Yun Hee Kim;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Mar 2017, volume: 16, issue:3, pages: 1579 - 1592
Publisher: IEEE
 
» Single Defect Discharge Events in Vertical-Nanowire Tunnel-FETs
Abstract:
In this paper, we investigate the single defect discharge events in Ge-source n-type vertical nanowire tunnel field effect transistors, by monitoring the relaxation phase which follows bias temperature instability (BTI) stress. Threshold voltage shift induced by single discharge events follows a bimodal Weibull distribution, with the location parameter of the second mode being significantly higher than the first one. Both modes are temperature independent. Based on TCAD simulations, we propose that the second mode is associated with defects located at the source/channel junction close to the channel/oxide interface, while the first mode is ascribed to oxide traps far from the source/channel junction. Although present in smaller numbers, such traps with a larger average impact on the device characteristics are expected to dominate the BTI-induced variability in a large population of nanoscale devices for realistic applications.
Autors: Antonio Fiore;Jacopo Franco;Moonju Cho;Felice Crupi;Sebastiano Strangio;Philippe J. Roussel;Rita Rooyackers;Nadine Collaert;Dimitri Linten;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Mar 2017, volume: 17, issue:1, pages: 253 - 258
Publisher: IEEE
 
» Single-Antenna FMCW Radar CMOS Transceiver IC
Abstract:
This paper presents a CMOS transceiver IC for a single-antenna frequency-modulated continuous wave (FMCW) radar. Since transmitter (Tx) leakage is critical in a single antenna radar with CMOS technology, a comprehensive leakage canceling technique is proposed. It is able to cancel all the leakages caused by antenna reflection, asymmetry of a balanced structure, and lossy substrate without additional power or area. Even-order harmonic leakages from the power amplifier (PA) are also reduced by an even-harmonic filter, which is implemented simply by removing the real ground from the symmetrical point of the PA output transformer. Matching networks are simplified by using a modified coupler structure. A low-noise combining amplifier is used to make the combining circuit compact. As a result, the transceiver achieves the output power of −1.6 dBm, the phase noise of −105.44 dBc/Hz at 1MHz offset, the receiver (Rx) gain of 15.3 dB, and the noise figure of 11.6 dB. Tx leakages are canceled so that the isolation between Tx and Rx is 47.3 dB. The chip consumes 74.1 mA from a 1.5-V power supply. Despite the high integration level, the chip area including pads is 1.7 mm 0.9 mm. A -band FMCW radar module with a single antenna is implemented with this chip.
Autors: Gitae Pyo;Choul-Young Kim;Songcheol Hong;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Mar 2017, volume: 65, issue:3, pages: 945 - 954
Publisher: IEEE
 
» Single-Layer Focusing Gradient Metasurface for Ultrathin Planar Lens Antenna Application
Abstract:
A single-layer focusing gradient metasurface (MS) built by one element-group is proposed. The element-group is designed by well connecting the phase shift range of two similar single-layer elements under the condition of transmitting efficiencies over 0.7. The proposed MS can focus the propagating plane wave on a point and a patch antenna is placed at its focus to build a high-gain planar lens antenna. This lens antenna achieves pencil-shaped far-field radiation pattern with a simulation peak gain of 16.7 dB at 10 GHz. The single-layer structure makes it easy to fabricate the MS with low profile and satisfying performances. Finally, the MS and the patch antenna are fabricated, assembled, and measured. The measured results are in good agreement with the simulations.
Autors: Haipeng Li;Guangming Wang;Jiangang Liang;Xiangjun Gao;Haisheng Hou;Xinyan Jia;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1452 - 1457
Publisher: IEEE
 
» Six-Port Reflectometer Using Edge-Coupled Microstrip Couplers
Abstract:
This letter presents the design of a six-port reflectometer (SPR), which makes use of edge-coupled, coupled-line microstrip couplers. By designing the couplers to have coupling slightly larger than the isolation, good -point placement on the complex plane is obtained. The SPR -points are obtained by a proposed two-step process using two standard terminations—a matched load and an open circuit load. The designed SPR has been tested using various loads and the computed load reflection coefficients have been compared against those of a standard commercial Vector Network Analyzer. The raw dynamic range is 21–39 dB in the frequency range from 1.6 to 2.2 GHz and the uncalibrated load reflection coefficients follow the expected values closely, with average phase error spread of only about 2.7%–7.7%. The designed SPR is fabricated on FR4 substrate. It achieves a reduction in size due to lesser number of components and is ideal for narrowband and low cost use.
Autors: Debapratim Ghosh;Girish Kumar;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 245 - 247
Publisher: IEEE
 
» Sizing of Stand-Alone Solar PV and Storage System With Anaerobic Digestion Biogas Power Plants
Abstract:
This paper presents a deterministic approach for sizing a solar photovoltaic (PV) and energy storage system (ESS) with anaerobic digestion (AD) biogas power plant (BPP) to meet a proportional scaled-down demand of the national load in Kenya, Africa. The aim is to achieve a minimal levelized cost of energy (LCOE) for the system while minimizing the energy imbalance between generation and demand due to AD generator constraint and solar resource. This system also aims to maximize the sizing of PV as to follow the future trend of high penetration of PV. LCOE for the system and a levelized cost of delivery (LCOD) are calculated for the hybrid energy system with the presence of energy storage. Four years of solar data collected from Johannesburg, Africa, are used for system sizing purposes. An in-depth study of the optimization problem has been given and particle swarm optimization with the interior point method is chosen for solar panel sizing. The optimal sizing ratio for the generation sources AD and PV is 2.4:5. The results show that the hybrid system will be cost effective compared to the AD-only system when the discount rate drops below 8% with the current technology costs.
Autors: Chun Sing Lai;Malcolm D. McCulloch;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2112 - 2121
Publisher: IEEE
 
» Slicer Architectures for Analog-to-Information Conversion in Channel Equalizers
Abstract:
The scaling of analog-to-digital converter (ADC) power consumption with communication bandwidth imposes severe limits on its precision, which significantly impacts receiver performance. In this paper, we consider a “space-time” generalization of the flash architecture by allowing a fixed number of slicers to be dispersed in time (i.e., sampling offset) as well as space (i.e., amplitude), with the goal of investigating its capabilities for analog-to-information conversion (i.e., enabling reliable recovery of digital information, rather than faithful reproduction of the input signal) in the context of channel equalization for binary signaling over a dispersive channel. We first study standard symbol-spaced ADC with severe quantization constraints, estimating the minimum number of slicers needed to avoid error floors. We observe that the performance is sensitive to channel realization and sampling phase, which motivates a more flexible space-time architecture. Using ideas similar to those underlying compressive sensing, we prove that such architectures have no fundamental limitations in theory: randomly dispersing enough one-bit slicers over space and time does provide information sufficient for reliable equalization. We then focus on practical designs for symbol-spaced and fractionally-spaced sampling subject to a constraint on the number of slicers, and propose an algorithm for optimizing slicer thresholds, which significantly improves performance over a standard design.
Autors: Aseem Wadhwa;Upamanyu Madhow;Naresh R. Shanbhag;
Appeared in: IEEE Transactions on Communications
Publication date: Mar 2017, volume: 65, issue:3, pages: 1234 - 1246
Publisher: IEEE
 
» Smart Contracts - Dumb Idea
Abstract:
Increasingly in e-commerce, smart contracts have relied on the code as the contract. But code can be hacked and fail, leaving multiple parties potentially exposed to legal gray areas, great financial loss, and little recourse. Here, Kieron O'Hara considers the ramifications of such contracts by exploring what happened when the Ethereum platform was hacked in the summer of 2016.
Autors: Kieron O'Hara;
Appeared in: IEEE Internet Computing
Publication date: Mar 2017, volume: 21, issue:2, pages: 97 - 101
Publisher: IEEE
 
» Smart Power Devices and ICs Using GaAs and Wide and Extreme Bandgap Semiconductors
Abstract:
We evaluate and compare the performance and potential of GaAs and of wide and extreme bandgap semiconductors (SiC, GaN, Ga2O3, and diamond), relative to silicon, for power electronics applications. We examine their device structures and associated materials/process technologies and selectively review the recent experimental demonstrations of high voltage power devices and IC structures of these semiconductors. We discuss the technical obstacles that still need to be addressed and overcome before large-scale commercialization commences.
Autors: T. Paul Chow;Ichiro Omura;Masataka Higashiwaki;Hiroshi Kawarada;Vipindas Pala;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 856 - 873
Publisher: IEEE
 
» Social-Aware Video Recommendation for Online Social Groups
Abstract:
Group recommendation plays a significant role in today's social media systems, where users form social groups to receive multimedia content together and interact with each other, instead of consuming the online content individually. Limitations of traditional group recommendation approaches are as follows. First, they usually infer group members’ preferences by their historical behaviors, failing to capture inactive users’ preferences from the sparse historical data. Second, relationships between group members are not studied by these approaches, which fail to capture the inherent personality of members in a group. To address these issues, we propose a social-aware group recommendation framework that jointly utilizes both social relationships and social behaviors to not only infer a group's preference, but also model the tolerance and altruism characteristics of group members. Based on the observation that the following relationship in the online social network reflects common interests of users, we propose a group preference model based on external experts of group members. Furthermore, we model users’ tolerance (willingness to receive content not preferred) and altruism (willingness to receive content preferred by friends). Finally, based on the group preference model, we design recommendation algorithms for users under different social contexts. Experimental results demonstrate the effectiveness of our approach, which significantly improves the recommendation accuracy against traditional approaches, especially in the cases of inactive group members.
Autors: Lifeng Sun;Xiaoyan Wang;Zhi Wang;Hong Zhao;Wenwu Zhu;
Appeared in: IEEE Transactions on Multimedia
Publication date: Mar 2017, volume: 19, issue:3, pages: 609 - 618
Publisher: IEEE
 
» Socio-Ethical Implications of Implantable Technologies in the Military Sector [Guest Editorial]
Abstract:
Autors: Katina Michael;M.G. Michael;Jai C. Galliot;Rob Nicholls;
Appeared in: IEEE Technology and Society Magazine
Publication date: Mar 2017, volume: 36, issue:1, pages: 7 - 9
Publisher: IEEE
 
» Soft Errors Induced by High-Energy Electrons
Abstract:
In the semiconductor reliability community, soft error research has primarily focused on neutrons and alpha particles. However, there are certain situations and environments in which high-energy electrons may also lead to soft errors. In this paper, we show that high energy electrons and the secondary particles created by them are capable of producing soft errors. In this paper, the energy dependence of electron-induced soft errors in a 28 nm bulk CMOS SRAM-based FPGA is recorded. Error rates are measured in both the embedded RAM and configuration RAM of the FPGA. This paper is the first research to explore the energy dependence of electron-induced single-event upsets in a commercial-off-the-shelf device. The measured electron-induced error cross sections are between and /bit depending on memory cell tested and the electron energy. Monte Carlo energy deposition simulations are used to further explore the mechanisms involved.
Autors: Matthew J. Gadlage;Austin H. Roach;Adam R. Duncan;Aaron M. Williams;Dobrin P. Bossev;Matthew J. Kay;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Mar 2017, volume: 17, issue:1, pages: 157 - 162
Publisher: IEEE
 
» Soft Magnetic Material Status and Trends in Electric Machines
Abstract:
This paper gives an overview on the history and trends of magnetic materials used in electrical machines and motors. The presented materials include silicon–iron, nickel–iron, and cobalt–iron lamination steels, as well as amorphous and nanocrystalline magnetic materials and soft magnetic composites. Development trends and current usage of these selected materials are presented, giving an outlook on the new magnetic material research with regard to electrical machine applications.
Autors: Andreas Krings;Aldo Boglietti;Andrea Cavagnino;Steve Sprague;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2405 - 2414
Publisher: IEEE
 
» Soft-Failures Induced by System-Level ESD
Abstract:
Hundreds of static discharges were directed to a circuit board containing a custom test chip, and the resulting soft-failures were recorded. The large time-derivative of the ESD current is the primary cause of soft-failures in this system. Magnetic coupling between traces and bondwires produces glitches at IO pins; the magnitude of these glitches is increased by the bounce of the on-chip supply net relative to the on-board supply. Additionally, logic upsets due to substrate current collection are observed when the equipment-under-test is tethered, i.e., when it has a low impedance path to Earth-ground.
Autors: Nicholas A. Thomson;Yang Xiu;Elyse Rosenbaum;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Mar 2017, volume: 17, issue:1, pages: 90 - 98
Publisher: IEEE
 
» Software Versus Hardware Approach to Emissions Monitoring
Abstract:
Many operations use hardware-based continuous emissions monitoring systems (CEMS) to track boiler emissions. This hardware approach uses pumps, filters, and analyzing instruments to draw emissions from the combustion equipment and measure their levels. Using hardware can be costly and time consuming as it requires daily deployments of calibration gases to confirm the system is providing accurate measurements. And when CEMs fail, data blackouts can occur. In addition, the lifespan of hardware is short, averaging eight to ten years. Due to these factors, more and more industrial operators are abandoning hardware in favor of software for emissions monitoring. This software approach is often referred to as a predictive emissions monitoring system. This paper compares the hardware and software approaches, and features a boiler application case study to showcase the financial advantages of the software approach.
Autors: Keith Smith;Dawn Cole;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 1717 - 1721
Publisher: IEEE
 
» Solar Energy Used for Grid Connection: A Detailed Assessment Including Frequency Response and Algorithm Comparisons for an Energy Conversion System
Abstract:
To help reduce losses in a distributed generation system, this article proposes a suitable method involving a three-phase multifunctional grid-connected solar energy conversion system (SECS). A two-stage circuit topology is used in this work; the first stage is a boost converter, which serves the purpose of maximum power point tracking (MPPT), and the second stage is a four-leg voltage source converter (VSC), which serves the purpose of feeding extracted energy along with improving power quality in the distribution system. The SECS not only feeds solar photovoltaic (SPV) energy into the grid but also acts to balance grid currents, compensate for reactive power, eliminate harmonics, and mitigate neutral current. A feedforward term for the SPV contribution is used to improve the dynamic response for climatic changes. The PV array voltage is continuously adjusted with the help of a boost converter to achieve MPPT, whereas the dc-link voltage of the VSC is kept constant using a proportional-integral (PI) controller. A second-order generalized integrator quadrature (SOGI-Q)-based algorithm is proposed for the control of a four-leg VSC.
Autors: Chinmay Jain;Bhim Singh;
Appeared in: IEEE Industry Applications Magazine
Publication date: Mar 2017, volume: 23, issue:2, pages: 37 - 50
Publisher: IEEE
 
» Solar Potential Analysis Method Using Terrestrial Laser Scanning Point Clouds
Abstract:
Analysis of sunlight or solar potential requires the data for a targeted scene to be authentic and accessible as much as possible. In this regard, the data for a real-world scene acquired by ground-based laser scanners are comprehensive and convenient, thus potentially meeting this requirement. To get an accurate result and offer an automatic solution for sunlight analysis, this paper proposes a solar potential analysis method that is run directly on 3-D ground laser scanning point clouds. Our method simulates natural illumination, sunlight hours, and solar radiation of the targeted scene for a specified period. This method first extracts the region of interest (ROI) to obtain targeted points. Then, we compute solar position as a virtual light source and propose a control method acting on the ROI to constraint deviation from the point light source. Finally, we adopt the generalized hidden point removal algorithm to cast shadow of obstruction on the ROI. Besides, experiments to validate the shading method results are carried out for three different periods. The quantitative results in the Xiamen case evaluated by the Hausdorff distance demonstrate the advantage and feasibility of our proposed method.
Autors: Pengdi Huang;Ming Cheng;Yiping Chen;Dawei Zai;Cheng Wang;Jonathan Li;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Mar 2017, volume: 10, issue:3, pages: 1221 - 1233
Publisher: IEEE
 
» Solid Mathematical Marbling
Abstract:
Years of research have been devoted to computer-generated 2D marbling, whereas 3D marbling has yet to be explored. The proposed mathematical marbling of 3D solids supports a compact random-access vector representation, creating solid marbling textures by composing closed-form 3D pattern tool functions. The resulting representation is feature-preserving and resolution-independent, and it consumes very little memory. To facilitate the solid-marbling texture authoring process, the authors also developed an intuitive user interface and a genetic algorithm.
Autors: Shufang Lu;Xiaogang Jin;Aubrey Jaffer;Fei Gao;Xiaoyang Mao;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Mar 2017, volume: 37, issue:2, pages: 90 - 98
Publisher: IEEE
 
» Sound-Event Classification Using Robust Texture Features for Robot Hearing
Abstract:
Sound-event classification often utilizes time–frequency analysis, which produces an image-like spectrogram. Recent approaches such as spectrogram image features and subband power distribution image features extract the image local statistics such as mean and variance from the spectrogram. They have demonstrated good performance. However, we argue that such simple image statistics cannot well capture the complex texture details of the spectrogram. Thus, we propose to extract the local binary pattern (LBP) from the logarithm of the Gammatone-like spectrogram. However, the LBP feature is sensitive to noise. After analyzing the spectrograms of sound events and the audio noise, we find that the magnitude of pixel differences, which is discarded by the LBP feature, carries important information for sound-event classification. We thus propose a multichannel LBP feature via pixel difference quantization to improve the robustness to the audio noise. In view of the differences between spectrograms and natural images, and the reliability issues of LBP features, we propose two projection-based LBP features to better capture the texture information of the spectrogram. To validate the proposed multichannel projection-based LBP features for robot hearing, we have built a new sound-event classification database, the NTU-SEC database, in the context of social interaction between human and robot. It is publicly available to promote research on sound-event classification in a social context. The proposed approaches are compared with the state of the art on the RWCP database and the NTU-SEC database. They consistently demonstrate superior performance under various noise conditions.
Autors: Jianfeng Ren;Xudong Jiang;Junsong Yuan;Nadia Magnenat-Thalmann;
Appeared in: IEEE Transactions on Multimedia
Publication date: Mar 2017, volume: 19, issue:3, pages: 447 - 458
Publisher: IEEE
 
» Sparse Grassmannian Embeddings for Hyperspectral Data Representation and Classification
Abstract:
We propose an approach for the representation and classification of hyperspectral data that exploits the geometric framework, the Grassmann manifold, i.e., a parameterization of -dimensional subspaces of . Multiple pixels from a data class are used to capture the variability of the class information using a subspace representation. We use two metrics defined on the Grassmannian, chordal and geodesic, and several pseudometrics to measure the pairwise distances between the points, i.e., subspaces. Once a distance matrix is generated, classical multidimensional scaling is applied to find a configuration of points with preserved or approximated original distances, thus realizing an embedding of the Grassmannian in Euclidean space. A sparse support vector machine trained in the embedding space simultaneously classifies embedded subspaces and selects a subset of optimal dimensions (features) using a weight ratio criterion. The resulting embedding affords substantial model order reduction for classification and data visualization. In many cases, this framework provides linearly separable representations even when raw data are not linearly separable. We analyze frameworks and compare binary classification results for several distances. Finally, we illustrate the embedding of multiple data classes.
Autors: Sofya Chepushtanova;Michael Kirby;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Mar 2017, volume: 14, issue:3, pages: 434 - 438
Publisher: IEEE
 
» Sparse Random Linear Network Coding With Precoded Band Codes
Abstract:
This letter proposes a sparse network code based on band matrices for lossy networks. The proposed code is precoded, has no wrap-around, and allows only a limited number of bands. Compared with existing works, the code simplifies decoding, enables more flexible recoding, and is able to significantly reduce the reception overhead that might be caused by recoding.
Autors: Ye Li;Jun Zhu;Zhihua Bao;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 480 - 483
Publisher: IEEE
 
» Spatial Analytic Interfaces: Spatial User Interfaces for In Situ Visual Analytics
Abstract:
As wearable devices gain acceptance, we need to ask, What will user interfaces look like in a post-smartphone world? Will these future interfaces support sophisticated interactions in a mobile context? The authors draw from visual analytics concepts to address the growing need for individuals to manage information on personal devices. Spatial analytic interfaces (SAIs) can leverage the benefits of spatial interaction to enable everyday visual analytics tasks to be performed in-situ, at the most beneficial place and time. They explore the possibilities for such interfaces using head-worn display technology and discuss current developments and future research goals for the successful development of SAIs.
Autors: Barrett Ens;Pourang Irani;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Mar 2017, volume: 37, issue:2, pages: 66 - 79
Publisher: IEEE
 
» Spatial Logistic Regression for Support-Vector Classification of Hyperspectral Imagery
Abstract:
The traditional use of support-vector machines for hyperspectral imagery exploits spectral information alone; however, classifiers that incorporate spatial context have witnessed increasing interest due to their potential for significant improvement over spectral-only approaches. A new paradigm for spatial-spectral support-vector classification is introduced in which spatial context is included into the logistic regression commonly used with support-vector classifiers to provide a probabilistic output. In experimental results, the proposed approach is compared to methods representative of two prominent families of spatial-spectral support-vector classifiers—composite kernels and postprocessing regularization—and it is observed that the proposed approach provides superior classification accuracy.
Autors: Wu Liu;James E. Fowler;Chunhui Zhao;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Mar 2017, volume: 14, issue:3, pages: 439 - 443
Publisher: IEEE
 
» Spatial-Aware Collaborative Representation for Hyperspectral Remote Sensing Image Classification
Abstract:
Representation-residual-based classifiers have attracted much attention in recent years in hyperspectral image (HSI) classification. How to obtain the optimal representa-tion coefficients for the classification task is the key problem of these methods. In this letter, spatial-aware collaborative representation (CR) is proposed for HSI classification. In order to make full use of the spatial–spectral information, we propose a closed-form solution, in which the spatial and spectral features are both utilized to induce the distance-weighted regularization terms. Different from traditional CR-based HSI classification algorithms, which model the spatial feature in a preprocessing or postprocessing stage, we directly incorporate the spatial information by adding a spatial regularization term to the representation objective function. The experimental results on three HSI data sets verify that our proposed approach outperforms the state-of-the-art classifiers.
Autors: Junjun Jiang;Chen Chen;Yi Yu;Xinwei Jiang;Jiayi Ma;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Mar 2017, volume: 14, issue:3, pages: 404 - 408
Publisher: IEEE
 
» Spatial-Temporal Dynamic Monitoring of Vegetation Recovery After the Wenchuan Earthquake
Abstract:
Mountainous vegetation recovery after major earthquakes has important implications for preventing postseismic soil erosion and geo-hazards. However, regional recovery processes of the postseismic vegetation and its spatial patterns have not been thoroughly studied. In this paper, we examined the vegetation recovery processes following the 2008 Wenchuan earthquake (Ms. 7.8) using 16-day interval MODIS normalized difference vegetation index time series from 2000 to 2014. The Savitzky–Golay filter and cross-correlogram spectral matching were used to eliminate the influences of cloud and intraannual phenology. Change vector analysis was applied to measure the postseismic vegetation recovery conditions for each year. We find that the heavily affected vegetation areas are mainly located along the southern part of the earthquake surface rupture. Additionally, five major affected vegetation types have been identified: shrubland, grassland, broadleaf/mixed, needleleaf, and plantation. Shrubland represents the largest fraction of vegetation type in the heavily affected area, whereas plantation comprises the smallest fraction of vegetation type in the heavily affected area. Further analysis indicates that the changing trend of postseismic vegetation conditions in the first six years can be grouped into three classes: recovering, fluctuating, and deteriorating. Recovering and fluctuating classes cover 59% and 37% of the heavily affected areas, respectively, and are the two dominant postseismic vegetation classes. In contrast, the deteriorating recovery class covers just 4% of the affected areas. The recovering vegetation is primarily located around the epicenter, and most of the fluctuating classes is located to the northeast of the epicenter. These results demonstrate that the Wenchuan earthquake has long-term and important influences on mountain vegetation, and more attention shoul- be given to the locations of deteriorating and fluctuating vegetation following mountain disasters.
Autors: Wentao Yang;Wenwen Qi;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Mar 2017, volume: 10, issue:3, pages: 868 - 876
Publisher: IEEE
 
» Spatial-Temporal Network Coding Based on BATS Code
Abstract:
Erasure networks can usually benefit from both spatial and temporal network coding, i.e., coding across packets both from different network edges as well as from different time slots. In this letter, we propose a joint spatial and temporal networking scheme with finite temporal coding length by extending the batch sparse (BATS) code proposed by Yang and Yeung. For the original BATS code, the batch size is usually set as the temporal coding length . With the proposed spatial-temporal BATS code, a larger batch size , with being the min-cut of the network, is used so that the spatial network coding can be applied together with temporal network coding. Simulation results show that the proposed scheme achieves significant throughput gain over the pure spatial or temporal network coding schemes.
Autors: Xiaoli Xu;Yong Liang Guan;Yong Zeng;Chee-Cheon Chui;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 620 - 623
Publisher: IEEE
 
» Spatio-Temporal Waveform Design for Multiuser Massive MIMO Downlink With 1-bit Receivers
Abstract:
Internet-of-Things (IoT) refers to a high-density network of low-cost, low-bitrate terminals and sensors where low energy consumption is also one central feature. As the power budget of classical receiver chains is dominated by the high-resolution analog-to-digital converters (ADCs), there is a growing interest toward deploying receiver architectures with reduced bit or even 1-bit ADCs. In this paper, we study waveform design, optimization, and detection aspects of multiuser massive MIMO downlink, where user terminals adopt very simple 1-bit ADCs with oversampling. In order to achieve spectral efficiency higher than 1 bit/s/Hz per real dimension, and per receiver antenna, we propose a two-stage precoding structure, namely, a novel quantization precoder followed by maximum-ratio transmission or zero-forcing-type spatial channel precoder which jointly form the multiuser multiantenna transmit waveform. The quantization precoder outputs are designed and optimized, under appropriate transmitter and receiver filter bandwidth constraints, to provide controlled intersymbol interference enabling the input symbols to be uniquely detected from 1-bit quantized observations with a low-complexity symbol detector in the absence of noise. An additional optimization constraint is also imposed in the quantization precoder design to increase the robustness against noise and residual interuser interference (IUI). The purpose of the spatial channel precoder, in turn, is to suppress the IUI and provide high beamforming gains such that good symbol error rates can be achieved in the presence of noise and interference. Extensive numerical evaluations illustrate that the proposed spatio-temporal precoder-based multiantenna waveform design can facilitate good multiuser link performance, despite the extremely simple 1-bit ADCs in the receivers, hence being one possible enabling technology for the future low-complexity IoT networks.
Autors: Ahmet Gokceoglu;Emil Björnson;Erik G. Larsson;Mikko Valkama;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Mar 2017, volume: 11, issue:2, pages: 347 - 362
Publisher: IEEE
 
» Special Section on the 25th IEEE International Symposium on Software Reliability Engineering (ISSRE 2014)
Abstract:
The papers in this special section were presented at the 2014 International Symposium on Software Reliability Engineering (ISSRE) that was held from 3 to 6 November 2014 in Naples, Italy.
Autors: R. Pietrantuono;K. Goseva-Popstojanova;C. Smidts;
Appeared in: IEEE Transactions on Reliability
Publication date: Mar 2017, volume: 66, issue:1, pages: 2 - 2
Publisher: IEEE
 
» Special Section on the International Conference on Data Engineering 2015
Abstract:
The papers in this special section were presented at the 31st International Conference on Data Engineering that was held in Seoul, Korea, on April 13-17, 2015. 17, 2015.
Autors: Wolfgang Lehner;Johannes Gehrke;Kyuseok Shim;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Mar 2017, volume: 29, issue:3, pages: 497 - 498
Publisher: IEEE
 
» Spectral-Efficient Quadrature Spatial Modulation Cooperative Amplify and Forward Spectrum-Sharing Systems
Abstract:
Quadrature spatial modulation (QSM) is a recent multiple-input–multiple-output (MIMO) digital transmission paradigm. Combining QSM with cooperative relaying in spectrum-sharing systems improves the overall spectral efficiency and enhances the communication reliability. In this paper, we study the performance of QSM-MIMO amplify-and-forward (AF) cooperative relaying spectrum-sharing systems, in which a multiantenna secondary source communicates with a secondary receiver with the help of a secondary AF relay in the presence of multiple primary receivers. In particular, a closed-form expression for the average pairwise error probability (PEP) of the secondary system is derived and used to obtain a tight upper bound of the average bit error probability (ABEP) over Rayleigh fading channels. In addition, a simple asymptotic, yet accurate, expression is derived and analyzed to show the effect of key parameters. Simulation results are presented to validate numerical analysis. Results reveal that QSM with cooperative relaying improves the spectrum-sharing systems' performance.
Autors: Ali Afana;Salama Ikki;Raed Mesleh;Ibrahem Atawi;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2857 - 2861
Publisher: IEEE
 
» Spectrum Sensing in Full-Duplex Cognitive Radio Networks Under Hardware Imperfections
Abstract:
Direct-conversion radio transceivers can offer reprogrammable and low-cost hardware solutions for full-duplex (FD) cognitive radio networks (CRNs). However, they are susceptible to radio-frequency (RF) impairments, such as in-phase (I) and quadrature (Q) imbalance (IQI), which can significantly limit spectrum sensing capabilities. This paper is devoted to quantifying and evaluating the effects of IQI in single- and multichannel energy detectors operating in FD mode under both cooperative and noncooperative spectrum sensing scenarios. In this context, closed-form expressions are derived for the false alarm and detection probabilities in the general case, where partial self-interference suppression (SIS) and joint transmitter (TX) and receiver (RX) IQI are considered. Furthermore, simplified closed-form expressions for the special cases, where either the RF front end is ideal or the SIS technique is perfect, are also presented. The presented analytical results have been verified through extensive simulations and indicate that the IQI and partial SIS can significantly affect spectrum sensing accuracy in FD-based CRNs. Specifically, if ideal RF front end is assumed, spectrum sensing error can significantly increase, leading to a reduction in the CRN performance and a negative effect on the performance of primary (PR) networks. Hence, when designing spectrum sharing algorithms for FD-based CRNs, the hardware impairments should be considered to improve the CRN performance while minimizing the negative effects on PR users.
Autors: Alexandros-Apostolos A. Boulogeorgos;Haythem A. Bany Salameh;George K. Karagiannidis;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2072 - 2084
Publisher: IEEE
 
» Spent Nuclear Fuel is not the Problem [Point of View]
Abstract:
Why are terms like “dread,” “danger,” and “intractable” applied to describe the management of the spent nuclear fuel produced by today’s commercial nuclear reactors? The small mass and compact form of this spent fuel are the most positive attributes of nuclear power, when compared to the massive volumes of waste we discharge when fossil fuels are burned.
Autors: Per F. Peterson;
Appeared in: Proceedings of the IEEE
Publication date: Mar 2017, volume: 105, issue:3, pages: 411 - 414
Publisher: IEEE
 
» Spurring Innovation in Spatial Haptics: How Open-Source Hardware Can Turn Creativity Loose
Abstract:
This article discusses an open-hardware robotics kit approach for designing spatial haptic interfaces. Our development of an open-source haptic device kit called WoodenHaptics, for which blueprints have been made available online for free download, enables interaction designers with little electromechanical experience to modify, manufacture, and assemble fully working haptic devices. This article addresses the processes of open-sourcing spatial haptic devices by covering the key mechanical and electrical principles needed for high-fidelity haptic rendering, the mathematical foundations for spatial haptics, the challenges to open-sourcing software and hardware and teaching it to different communities, and the history of the WoodenHaptics project itself.
Autors: Michael C. Yip;Jonas Forsslund;
Appeared in: IEEE Robotics & Automation Magazine
Publication date: Mar 2017, volume: 24, issue:1, pages: 65 - 76
Publisher: IEEE
 
» SSIT's 45th Anniversary [President's Message]
Abstract:
Autors: Paul Cunningham;
Appeared in: IEEE Technology and Society Magazine
Publication date: Mar 2017, volume: 36, issue:1, pages: 5 - 9
Publisher: IEEE
 
» Stability Analysis of the Shunt Regulator With Nonlinear Controller in PCU Based on Describing Function Method
Abstract:
The shunt regulator is a key part of the power conditioning unit, which is becoming more and more important in the spacecrafts. Due to the nonlinear link, the switch operating with hysteresis control, the shunt regulator is a nonlinear system; however, the stability analysis method for the system is still grounded on the approximate linearization method, which neglects some of the ac and dc characteristics. In this paper, a novel stability analysis method for the nonlinear systems is proposed based on the describing function, which can be used to model the nonlinear link in the shunt regulator system. Further, the different conclusion of the shunt regulator system stability are drawn, by the approximate linearization method and the stability analysis method proposed in this paper, respectively. Finally, the simulation and experimental results prove the correctness of the stability analysis method with describing function and discover the incompletion of the approximate linearization methods on the stability analysis. Therefore, this paper provides a new way to analyze the stability of the nonlinear systems.
Autors: Hong Li;Shiheng Wang;Jinhu Lü;Xiaojie You;Xinghuo Yu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Mar 2017, volume: 64, issue:3, pages: 2044 - 2053
Publisher: IEEE
 
» Stability Improvement of a Two-Area Power System Connected With an Integrated Onshore and Offshore Wind Farm Using a STATCOM
Abstract:
This paper presents stability-improvement results of a two-area power system connected with an integrated onshore and offshore wind farm (WF) using a static synchronous compensator (STATCOM). The onshore WF of 19.8 MW is based on dynamic-slip induction generator, while the offshore WF of 100 MW is based on doubly-fed induction generator. The qd axis equivalent-circuit model is derived to establish the complete system model under three-phase balanced conditions. A lead-lag power-oscillation damping controller (PODC) of the STATCOM is designed by using the phase-compensation method based on modal control theory to damp out low-frequency oscillations of the studied two-area power system. A systematic strategy using a frequency-domain approach based on eigenvalue analysis and a time-domain approach based on nonlinear-model simulations is performed to evaluate the effectiveness of the proposed control scheme. It can be concluded from the simulation results that the proposed STATCOM joined with the designed PODC is capable of improving stability of the studied two-area power system connected with the integrated onshore and offshore WF under various disturbance conditions.
Autors: Li Wang;Che-Hao Chang;Bing-Lin Kuan;Anton V. Prokhorov;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 867 - 877
Publisher: IEEE
 
» Stability Region of $p$ -Persistent CSMA Systems
Abstract:
This letter investigates the stability region of -persistent carrier sense multiple access systems with users, where each user has an unlimited length of queue, its own arrival rate, and (re)transmission probability. To do this, we apply Foster–Lyapunov stability theorem and show the necessary and sufficient condition of the system stability in terms of the existence of queue-stabilizing (re)transmission probability. Then, using a multiobjective optimization problem, we characterize the boundary of the stability region.
Autors: Jun-Bae Seo;Hu Jin;
Appeared in: IEEE Communications Letters
Publication date: Mar 2017, volume: 21, issue:3, pages: 652 - 655
Publisher: IEEE
 
» Stabilization and Entropy Reduction via SDP-Based Design of Fixed-Order Output Feedback Controllers and Tuning Parameters
Abstract:
This paper addresses the problem of designing fixed-order output feedback controllers and tuning parameters for reducing the instability of linear time-invariant (LTI) systems. Specifically, continuous-time (CT) and discrete-time (DT) LTI systems are considered, whose coefficients are rational functions of design parameters that are searched for in a given semi-algebraic set. Two instability measures are considered, the first defined as the spectral abscissa (CT case) or the spectral radius (DT case), and the second defined as the sum of the real parts of the unstable eigenvalues (CT case) or the product of the magnitudes of the unstable eigenvalues (DT case). Two sufficient conditions are given for establishing either the non-existence or the existence of design parameters that reduce the considered instability measure under a desired value. These conditions require to solve a semidefinite program (SDP), which is a convex optimization problem, and to find the roots of a multivariate polynomial, which is a difficult problem in general. To overcome this difficulty, a technique based on linear algebra operations is exploited, which easily provides the sought roots in common cases by taking into account the structure of the polynomial under consideration. Also, it is shown that these conditions are also necessary by increasing enough the size of the SDP under some mild assumptions. Lastly, it is explained how the proposed methodology can be used to search for design parameters that minimize a given cost function while reducing the instability.
Autors: Graziano Chesi;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Mar 2017, volume: 62, issue:3, pages: 1094 - 1108
Publisher: IEEE
 
» Stabilization Effect on Hydrogen Pressure for Fuel Cell Fueled by Sodium Tetrahydroborate With Multiple Power Converter Control
Abstract:
A hydrogen generation system for fuel-cell (FC) hybrid electric vehicles fueled by powdery sodium tetrahydroborate (STEPS) has been proposed and developed. In this system, it is difficult to control the pressure of the hydrogen supplied to a FC stack. This problem may cause damage to the solid polymer electrolyte membrane of the FC stack or an imbalance in the generated electrical power. As a solution to this problem, a control method that uses multiple power converters, consisting of boost and bidirectional choppers, is applied to a prototype vehicle fueled by STEPS. The proposed control method can suppress rapid variation in the output power of the FC stack. This study shows that the proposed control method can improve the performance of hydrogen pressure control through test runs using a prototype vehicle and simulations using the derived model.
Autors: Keisuke Tomoda;Yuto Aisaka;Taishi Fukuzawa;Nobukazu Hoshi;Noboru Katayama;Atsuhiro Yoshizaki;Keiichi Hirata;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Mar 2017, volume: 53, issue:2, pages: 1200 - 1209
Publisher: IEEE
 
» Standards Energize Automation and Control [Standards]
Abstract:
Examines the relationship between standards development and automation and control. Over the past decades, there has been a boom in automation. We have come to depend on automation techniques and tools. Software and hardware tools facilitate the transactions of financial markets, energy production and distribution, travel, and modern production plants for almost all products. Discusses work being done by standards organizations, including the IEEE to ensure the quality and safety of automated products/services. Standards address a range of issues, including but not limited to various protocols to help maximize product functionality and compatibility, facilitate interoperability, and support consumer safety and public health. Standards form the fundamental building blocks for product development by establishing consistent protocols that can be universally understood and adopted.
Autors: Daleep Mohla;
Appeared in: IEEE Industry Applications Magazine
Publication date: Mar 2017, volume: 23, issue:2, pages: 92 - 92
Publisher: IEEE
 
» Startup Takes On Growing Demand for Visual Search Technology
Abstract:
Learn how one startup company, ViSenze, found success by choosing the right vertical domain and leveraging high-quality training data.
Autors: Guangda Li;Chua Tat-Seng;
Appeared in: IEEE Multimedia
Publication date: Mar 2017, volume: 24, issue:1, pages: 17 - 19
Publisher: IEEE
 
» State Estimation for the Individual and the Population in Mean Field Control With Application to Demand Dispatch
Abstract:
This paper concerns state estimation problems in a mean field control setting. In a finite population model, the goal is to estimate the joint distribution of the population state and the state of a typical individual. The observation equations are a noisy measurement of the population. The general results are applied to demand dispatch for regulation of the power grid, based on randomized local control algorithms. In prior work by the authors it is shown that local control can be designed so that the aggregate of loads behaves as a controllable resource, with accuracy matching or exceeding traditional sources of frequency regulation. The operational cost is nearly zero in many cases. The information exchange between grid and load is minimal, but it is assumed in the overall control architecture that the aggregate power consumption of loads is available to the grid operator. It is shown that the Kalman filter can be constructed to reduce these communication requirements, and to provide the grid operator with accurate estimates of the mean and variance of quality of service (QoS) for an individual load.
Autors: Yue Chen;Ana Bušić;Sean P. Meyn;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Mar 2017, volume: 62, issue:3, pages: 1138 - 1149
Publisher: IEEE
 
» State-Machine and Deferred-Update Replication: Analysis and Comparison
Abstract:
In the paper, we analyze and experimentally compare two popular replication schemes relying on atomic broadcast: state machine replication (SMR) and deferred update replication (DUR). We estimate the lower bounds on the time of executing requests by the SMR and DUR systems running on multi-core servers. We also consider variants of systems that can process read-only requests with a lower overhead. In the analysis of DUR, we consider conflict patterns. We then formally show the scalability of SMR and DUR, which reflects the capacity of systems to effectively utilize an increasing number of processor cores. Next, we compare SMR and DUR experimentally under different levels of contention, using several benchmarks. We show throughput, abort rate (in DUR), and network congestion. The key results of our work are that neither system is superior in all cases, and that the theoretical and experimental results are heavily influenced by the dominance of either the CPU execution time or atomic broadcast time. We therefore propose to combine both replication schemes and gain the best of both worlds.
Autors: Paweł T. Wojciechowski;Tadeusz Kobus;Maciej Kokociński;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Mar 2017, volume: 28, issue:3, pages: 891 - 904
Publisher: IEEE
 
» Statistical Analysis and Comparison of 2T and 3T1D e-DRAM Minimum Energy Operation
Abstract:
Bio-medical wearable devices restricted to their small-capacity embedded-battery require energy-efficiency of the highest order. However, minimum-energy point (MEP) at sub-threshold voltages is unattainable with SRAM memory, which fails to hold below 0.3V because of its vanishing noise margins. This paper examines the minimum-energy operation point of 2T and 3T1D e-DRAM gain cells at the 32-nm technology node with different design points: up-sizing transistors, using high-th transistors, read/write wordline assists; as well as operating conditions (i.e., temperature). First, the e-DRAM cells are evaluated without considering any process variations. Then, a full-factorial statistical analysis of e-DRAM cells is performed in the presence of threshold voltage variations and the effect of upsizing on mean MEP is reported. Finally, it is shown that the product of the read and write lengths provides a knob to tradeoff energy-efficiency for reliable MEP energy operation.
Autors: Manish Rana;Ramon Canal;Esteve Amat;Antonio Rubio;
Appeared in: IEEE Transactions on Device and Materials Reliability
Publication date: Mar 2017, volume: 17, issue:1, pages: 42 - 51
Publisher: IEEE
 
» Statistical Considerations in the Creation of Realistic Synthetic Power Grids for Geomagnetic Disturbance Studies
Abstract:
Studies to evaluate the power system impacts of geomagnetic disturbances (GMDs) can benefit from geographically realistic public test cases to validate methodologies and analysis tools. Presently very few GMD test cases exist that are not restricted by data confidentiality. In this paper, we outline a method to generate completely synthetic transmission system networks suitable for GMD studies. Public energy and census data form the basis for generation, load, and geographic substation placement. The transmission line topology of the synthetic network is designed to match statistical characteristics observed on the Eastern Interconnect in North America: average nodal degree, average shortest path length, and average clustering coefficient. We apply the Delaunay triangulation to transmission network synthesis, showing it provides an excellent starting place for generating realistic topologies. A 150-bus case is developed and released with benchmark GMD results, for using in testing GMD models and methods.
Autors: Adam B. Birchfield;Kathleen M. Gegner;Ti Xu;Komal S. Shetye;Thomas J. Overbye;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1502 - 1510
Publisher: IEEE
 
» Statistical Dependence of Gate Metal Work Function on Various Electrical Parameters for an n-Channel Si Step-FinFET
Abstract:
This paper presents a 3-D statistical simulation study of an n-channel Si step-FinFET due to work-function variability depending on grain orientation of metal gate. The statistical fluctuation induced by metal gate granularity on threshold-voltage (), ON current (), and OFF current () are estimated for a wide range of channel length and effective fin width for varying average grain size using Technology Computer Aided Design simulator. We investigated the effect of grain on magnitude of variability and also on shapes of various electrical parameters of distribution. The results indicate that decreases for increase in each dimension of the device. The value of , and reduces as channel length increases. However, and increase as fin width increases. The distribution of electrical parameters is near to normal for small grain size and becomes bimodal at large grain size. The proposed structure shows excellent behavior in terms of threshold-voltage (), subthreshold swing, and current ratio () compared with conventional FinFET at high temperature. It is found that the hot carrier effect reduces with increased effective channel width.
Autors: Rajesh Saha;Brinda Bhowmick;Srimanta Baishya;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 969 - 976
Publisher: IEEE
 
» Statistical Distributions of the Copolarized and Cross-Polarized Phase Differences of Stratified Media
Abstract:
We determine the statistical distributions of the copolarized and cross-polarized phase differences of fields scattered from a stack of two 2-D rough interfaces in any observation plane. This communication is carried within the framework of the first-order small perturbation method. The probability laws are established for Gaussian distributions of heights and for infinite extension interfaces. We show that, outside the incidence plane, the cross-polarized phase difference is not uniformly distributed and contains information about the stratified medium.
Autors: Richard Dusséaux;Saddek Afifi;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1517 - 1521
Publisher: IEEE
 
» Statistical Meta-Analysis of Presentation Attacks for Secure Multibiometric Systems
Abstract:
Prior work has shown that multibiometric systems are vulnerable to presentation attacks, assuming that their matching score distribution is identical to that of genuine users, without fabricating any fake trait. We have recently shown that this assumption is not representative of current fingerprint and face presentation attacks, leading one to overestimate the vulnerability of multibiometric systems, and to design less effective fusion rules. In this paper, we overcome these limitations by proposing a statistical meta-model of face and fingerprint presentation attacks that characterizes a wider family of fake score distributions, including distributions of known and, potentially, unknown attacks. This allows us to perform a thorough security evaluation of multibiometric systems against presentation attacks, quantifying how their vulnerability may vary also under attacks that are different from those considered during design, through an uncertainty analysis. We empirically show that our approach can reliably predict the performance of multibiometric systems even under never-before-seen face and fingerprint presentation attacks, and that the secure fusion rules designed using our approach can exhibit an improved trade-off between the performance in the absence and in the presence of attack. We finally argue that our method can be extended to other biometrics besides faces and fingerprints.
Autors: Battista Biggio;Giorgio Fumera;Gian Luca Marcialis;Fabio Roli;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Mar 2017, volume: 39, issue:3, pages: 561 - 575
Publisher: IEEE
 
» Steep Switching Hybrid Phase Transition FETs (Hyper-FET) for Low Power Applications: A Device-Circuit Co-design Perspective–Part I
Abstract:
Hybrid-phase-transition FETs (Hyper-FETs) are recently proposed steep switching devices that utilize the phase transition materials (PTM) to achieve a boost in the ratio of ON ( and OFF currents (. Prototypical demonstrations of the Hyper-FET have shown performance improvement in comparison with conventional transistors, which motivates the evaluation of its device-circuit design space. In part I, we analyze the device aspects establishing the effects of the resistivity and phase transition thresholds of the PTM on the characteristics of Hyper-FETs. Our analysis shows that the ratio of insulating and metallic state resistivity ( and respectively) of the PTM needs to be higher than the of its host transistor to achieve performance improvement in Hyper-FET. For a host transistor with and , .cm and .cm.cm is required to achieve roper device functionality with a boost in . Additionally, we establish the ranges of phase transition thresholds that yield proper functionality of the Hyper-FETs considering different targets. The methodology of choosing appropriate PTM geometry to achieve the target device characteristics is also described. We show that with proper design, Hyper-FETs achieve 94% larger at iso- compared with a FinFET. We examine the circuit design aspects of Hyper-FET in part II.
Autors: Ahmedullah Aziz;Nikhil Shukla;Suman Datta;Sumeet Kumar Gupta;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 1350 - 1357
Publisher: IEEE
 
» Steering Focusing Waves in a Reverberation Chamber With Generalized Time Reversal
Abstract:
Generalized time reversal was introduced in a previous paper from a theoretical point of view. In this paper, experiments are conducted to demonstrate its application to a reverberation chamber, as a method for generating coherent wavefronts in a medium displaying random propagation. Wavefronts thus generated were sampled over a planar surface, confirming that they propagate as if in a free-space environment. The accuracy with which they match their free-space counterpart is not affected by changing their features, e.g., direction of arrival and focus. These results prove that a single excitation antenna can generate complex wavefronts when coupled to diffusive wave propagation.
Autors: Andrea Cozza;Florian Monsef;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Mar 2017, volume: 65, issue:3, pages: 1349 - 1356
Publisher: IEEE
 
» Stem Cell Plasticity and Niche Dynamics in Cancer Progression
Abstract:
Objective: Cancer stem cells (CSCs) have been hypothesized to initiate and drive tumor growth and recurrence due to their self-renewal ability. If correct, this hypothesis implies that successful therapy must focus primarily on eradication of this CSC fraction. However, recent evidence suggests stemness is niche dependent and may represent one of many phenotypic states that can be accessed by many cancer genotypes when presented with specific environmental cues. A better understanding of the relationship of stemness to niche-related phenotypic plasticity could lead to alternative treatment strategies. Methods: Here, we investigate the role of environmental context in the expression of stem-like cell properties through in-silico simulation of ductal carcinoma. We develop a two-dimensional hybrid discrete-continuum cellular automata model to describe the single-cell scale dynamics of multicellular tissue formation. Through a suite of simulations, we investigate interactions between a phenotypically heterogeneous cancer cell population and a dynamic environment. Results: We generate homeostatic ductal structures that consist of a mixture of stem and differentiated cells governed by both intracellular and environmental dynamics. We demonstrate that a wide spectrum of tumor-like histologies can result from these structures by varying microenvironmental parameters. Conclusion: Niche driven phenotypic plasticity offers a simple first-principle explanation for the diverse ductal structures observed in histological sections from breast cancer. Significance: Conventional models of carcinogenesis largely focus on mutational events. We demonstrate that variations in the environmental niche can produce intraductal cancers independent of genetic changes in the resident cells. Therapies targeting the microenvironmental niche may offer an alternative cancer prevention strategy.
Autors: Noemi Picco;Robert A. Gatenby;Alexander R. A. Anderson;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Mar 2017, volume: 64, issue:3, pages: 528 - 537
Publisher: IEEE
 
» Step JTE, an Edge Termination for UHV SiC Power Devices With Increased Tolerances to JTE Dose and Surface Charges
Abstract:
An edge termination method, referred to as guard-ring-assisted multistep junction termination extension (MS-GR-JTE), is presented for ultrahigh voltage silicon carbide (SiC) power devices. In comparisonwith other JTEs, the MS-GR-JTE creates a step electric field (EF) distribution with greatly reduced peak EF at the corners and edges of the device, resulting in a superior breakdown voltage (BV) performance with wide tolerances to JTE dose and SiC surface charges. According to the numerical simulations based on a 100--thick epilayer, an optimized MS-GR-JTE shows that the 15-kV BV performance with wide tolerances of cm to JTE dose and cm to positive surface charges are obtained, respectively, both superior to other compared JTEs.
Autors: Cai-Neng Zhou;Yan Wang;Rui-Feng Yue;Gang Dai;Jun-Tao Li;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 1193 - 1196
Publisher: IEEE
 
» Stepping Up Security with Signal Processing: Innovative tools and approaches address threats on multiple fronts [Special Reports]
Abstract:
Signal processing is helping to make life a little less scary. Cyberattacks, street crime, terrorist strikes, and other types of public threats have the potential to devastate lives, destroy businesses, and even bring down governments. Finding ways to defuse potential threats, as well as pinpoint perpetrators before they can act, is important for maintaining public security as well as ensuring a better quality of life for people worldwide.
Autors: John Edwards;
Appeared in: IEEE Signal Processing Magazine
Publication date: Mar 2017, volume: 34, issue:2, pages: 14 - 17
Publisher: IEEE
 
» Stochastic Long-Term Hydrothermal Scheduling With Parameter Uncertainty in Autoregressive Streamflow Models
Abstract:
The optimal scheduling of hydrothermal systems requires the representation of uncertainties in future streamflows to devise a cost-effective operations policy. Stochastic optimization has been widely used as a powerful tool to solve this problem but results will necessarily depend on the stochastic model used to generate future scenarios for streamflows. Periodic autoregressive (PAR) models have been widely used in this task. However, its parameters are typically unknown and must be estimated from historical data, incorporating a natural estimation error. Furthermore, the model is just a linear approximation of the real stochastic process. The consequence is that the operator will be uncertain about the correct linear model that should be used at each period. The objective of this work is to assess the impacts of incorporating the uncertainty of the parameters of the PAR models into a stochastic hydrothermal scheduling model. The proposed methodology is tested with case studies based on data from the Brazilian hydroelectric system. It is shown that when the uncertainty of the parameters is ignored, the policies given by the stochastic optimization tend to be too optimistic.
Autors: Bernardo Bezerra;Álvaro Veiga;Luiz Augusto Barroso;Mario Pereira;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 999 - 1006
Publisher: IEEE
 
» Stochastic Stability Condition for the Extended Kalman Filter With Intermittent Observations
Abstract:
In order to tackle the intermittent observations, this brief addresses the stochastic stability problem of the extended Kalman filter by means of analyzing the prediction error covariance matrix (PECM) and the estimation error performance of the estimator. With the transmitted measurement output of the filter modeled as a Bernoulli process, the existence of a crucial arrival rate is proved such that the PECM is mean bounded when the arrival rate exceeds a threshold value. Moreover, offline sufficient conditions for the stochastic stability of the estimation error are also derived. A numerical example is given to demonstrate the feasibility of the proposed method.
Autors: Xiangdong Liu;Luyu Li;Zhen Li;Tyrone Fernando;Herbert H. C. Iu;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Mar 2017, volume: 64, issue:3, pages: 334 - 338
Publisher: IEEE
 
» STRAD Wheel: Web-Based Library for Visualizing Temporal Data
Abstract:
Recent advances in web development, including the introduction of HTML5, have opened a door for visualization researchers and developers to quickly access larger audiences worldwide. Open source libraries for the creation of interactive visualizations are becoming more specialized but also modular, which makes them easy to incorporate in domain-specific applications. In this context, the authors developed STRAD (Spatio-Temporal-Radar) Wheel, a web-based library that focuses on the visualization and interactive query of temporal data in a compact view with multiple temporal granularities. This article includes two application examples in urban planning to help illustrate the proposed visualization's use in practice.
Autors: Diana Fernöndez-Prieto;Carol Naranjo-Valero;José Tiberio Hernández;Hans Hagen;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Mar 2017, volume: 37, issue:2, pages: 99 - 105
Publisher: IEEE
 
» Strategic Valuation of Smart Grid Technology Options in Distribution Networks
Abstract:
The increasing penetration of renewable distributed generation (DG) sources in distribution networks can lead to violations of network constraints. Thus, significant network reinforcements may be required to ensure that DG output is not constrained. However, the uncertainty around the magnitude, location, and timing of future DG capacity renders planners unable to take fully informed decisions and integrate DG at a minimum cost. In this paper, we propose a novel stochastic planning model that considers investment in conventional assets as well as smart grid assets such as demand-side response, coordinated voltage control and soft open points. The model also considers the possibility of active power generation curtailment of the DG units. A node-variable formulation has been adopted to relieve the substantial computational burden of the resulting mixed integer nonlinear programming problem. A case study shows that smart technologies can possess significant strategic value due to their inherent flexibility in dealing with different system evolution trajectories. This latent benefit remains undetected under traditional deterministic planning approaches which may hinder the transition to the smart grid.
Autors: Ioannis Konstantelos;Spyros Giannelos;Goran Strbac;
Appeared in: IEEE Transactions on Power Systems
Publication date: Mar 2017, volume: 32, issue:2, pages: 1293 - 1303
Publisher: IEEE
 
» Stray Magnetic Field Analysis of ITER Poloidal Field Converter Unit
Abstract:
Due to the space limitation and safety concerns, the non-same-phase anti-parallel connection structure is applied in the International Thermonuclear Experimental Reactor (ITER) Poloidal Field (PF) converter unit. Consequently, the electromagnetic interference caused by the strong stray magnetic field has been one of the main concerns in its design. And this paper mainly presents the stray magnetic field analysis of ITER PF converter unit. At first, an isolated phase bus (IPB) is designed for the shielding of the alternating magnetic field generated by the ac busbars to avoid overheating on ferromagnetic materials in the fire wall. The stray magnetic field on the fire wall is analyzed to verify the shielding effectiveness of the IPB. Then, the stray magnetic field generated by the converter bridges and dc reactors which is very hard to be shielded is analyzed separately. The results show that the stray magnetic field exceeds the limit value and will be a potential threat for the instrument and control (I&C) system. All the analysis presented in this paper will provide useful inputs for the electromagnetic compatibility design and test of the I&C system.
Autors: Yong Yang;Ming Zhang;Zhiquan Song;Minxue Xia;Kexun Yu;Li Jiang;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Mar 2017, volume: 45, issue:3, pages: 495 - 500
Publisher: IEEE
 
» Structure Detection of Wiener–Hammerstein Systems With Process Noise
Abstract:
Identification of nonlinear block-oriented models has been extensively studied. The presence of the process noise and more precisely its location in the block-oriented model essentially influence the development of a consistent identification algorithm. This paper is proposed with the aim to localize the process noise in the block-oriented model for accurate nonlinear modeling. To this end, the response of a Wiener–Hammerstein system is theoretically analyzed, and the disturbance component in the output, caused by the process noise preceding the static nonlinearity, is shown to be dependent on the input signal. Inspired by such a theoretical observation, a simple and new protocol is developed to determine the location of the process noise with respect to the static nonlinearity using an input signal that is periodic but nonstationary within one period. In addition, the proposed technique is promising to detect the type of certain static nonlinearity (e.g., dead zone and saturation). Finally, it is validated on a simulated example and a real-life benchmark.
Autors: Erliang Zhang;Maarten Schoukens;Johan Schoukens;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Mar 2017, volume: 66, issue:3, pages: 569 - 576
Publisher: IEEE
 
» Study of Bend Discontinuities in Substrate Integrated Gap Waveguide
Abstract:
This letter presents a study of bend discontinuities in the substrate integrated gap waveguide (SIGW), and proposes a simple solution to minimize the discontinuity effects. Both curved and chamfered right-angle bends are studied. It is found that with a proper ratio of the chamfered length and the bend via diameter, the possible cavity resonances can be suppressed and the desired performance is achieved. The curved bend, however, allows the bend via to have a larger diameter, which could be required due to the fabrication issue. This letter will be of great help to realize future feeding networks for SIGW antenna arrays or other types of cost-effective SIGW passive components, where many discontinuities are naturally present. The proposed discontinuity solution is validated experimentally by a fabricated SIGW prototype of two 90° bends.
Autors: Jing Zhang;Xiupu Zhang;Ahmed A. Kishk;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Mar 2017, volume: 27, issue:3, pages: 221 - 223
Publisher: IEEE
 
» Study of Formation and Development of Lubricant Bridge in Head–Disk Interface Using Molecular Dynamic Method
Abstract:
The lubricant bridge connecting the slider and the disk will significantly deteriorate the read–write stability of the hard disk drive. This paper builds a model of disk-lubricant-slider system. The coarse-grained bead-spring model is used to represent perfluoropolyethers molecules. And the molecular dynamic method is used to study the formation time and the molecule number of the lubricant bridge under different disk rotation speeds and slider flying heights. Furthermore, the influence of lubricant bridge on the pressure acting on the slider pad is also studied.
Autors: Xiangyu Dai;Jingshi Zhang;Shengnan Shen;Hui Li;Tianqi Zhai;Shijin Wu;Sheng Liu;Hejun Du;
Appeared in: IEEE Transactions on Magnetics
Publication date: Mar 2017, volume: 53, issue:3, pages: 1 - 4
Publisher: IEEE
 
» Study of GaN-Based LEDs With Hybrid SiO2 Microsphere/Nanosphere AntiReflection Coating as a Passivation Layer by a Rapid Convection Deposition
Abstract:
A hybrid SiO2 micro/nanospheres antireflection coating, deposited by a rapid convection deposition, acting as a passivation layer of GaN-based light-emitting diodes (LEDs) is studied in this paper. Since the critical angle could be enlarged by antireflection coating, Fresnel reflection could be reduced. In addition, due to the roughened surface of hybrid SiO2 microsphere/nanosphere antireflection coating, the scattering effect could be increased. Thus, the light extraction efficiency could be further enhanced. As compared with a conventional LED (device A), at 20 mA, the studied device C exhibits 18.7% enhancement in light output power without any degradation of electrical properties. Reduced leakage current could also be achieved. Therefore, the use of hybrid SiO2 microsphere/nanosphere antireflection coating could effectively improve the performance of GaN-based LEDs.
Autors: Chi-Hsiang Hsu;Yi-Chun Chan;Wei-Cheng Chen;Ching-Hong Chang;Jian-Kai Liou;Shiou-Ying Cheng;Der-Feng Guo;Wen-Chau Liu;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 1134 - 1139
Publisher: IEEE
 
» Study of Interface Traps in AlGaN/GaN MISHEMTs Using LPCVD SiNx as Gate Dielectric
Abstract:
Interface trapping is one of the most notorious effects that limit device performance in GaN-based MIS high electron mobility transistors (MISHEMTs). In this paper, we present a comprehensive study on interface traps in AlGaN/GaN MISHEMTs using low pressure chemical vapor deposition SiNx as gate dielectric. We combined the trapping analysis in MIS diodes and actual MISHEMTs to estimate the interface trap state densities ( and their distributions in the device, and to investigate their influence on device electrical properties. Two types of interface traps with different emission time constants, designated as “slow” and “fast” traps, were identified and characterized by means of pulse-mode current-voltage measurements and a frequency dependent conductance method. It was found that “fast” traps located in the device access region could be effectively restrained by passivation using plasma enhanced chemical vapor deposition SiNx. However, “slow” traps, no matter whether located beneath the metal gate or in the access region, were less influenced by passivation. Due to the strong interference of traps in the access region, extraction using the conventional conductance method was not accurate for the lateral GaN-based MIS diodes. A modified small-signal equivalent circuit that includes the impedance of traps in the access region is proposed. Proper passivation for the device access region is essential when using the conductance method for GaN-based MIS devices.
Autors: Xing Lu;Kun Yu;Huaxing Jiang;Anping Zhang;Kei May Lau;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 824 - 831
Publisher: IEEE
 
» Sub-100 mV Computing With Electro-Mechanical Relays
Abstract:
The energy efficiency of a CMOS digital logic circuit is fundamentally limited by the nonideal switching behavior of transistors, specifically their nonzero off-state current and finite subthreshold slope. In contrast, mechanical switches (relays) can achieve zero off-state current and perfectly abrupt switching characteristics; therefore, they have attracted growing interest for ultralow-power computing applications. A challenge for electro-mechanical relay technology is to reduce the hysteresis voltage, because this sets the minimum operating voltage of the relays. Herein, we report a surface-micromachinedelectrostatically actuated relaywith <70-mV hysteresis voltage, achieved by designing it to have relatively large structural stiffness and to operate in nonpull-inmode. A relay-based inverter circuit is demonstrated to operate reliably with a switching voltage below 100 mV, representing a significant milestone toward ultralow-power mechanical computing.
Autors: Chuang Qian;Alexis Peschot;Benjamin Osoba;Zhixin Alice Ye;Tsu-Jae King Liu;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 1323 - 1329
Publisher: IEEE
 
» Subband Filtered Multi-Carrier Systems for Multi-Service Wireless Communications
Abstract:
Flexibly supporting multiple services, each with different communication requirements and frame structure, has been identified as one of the most significant and promising characteristics of next generation and beyond wireless communication systems. However, integrating multiple frame structures with different subcarrier spacing in one radio carrier may result in significant inter-service-band-interference (ISBI). In this paper, a framework for multi-service (MS) systems is established based on a subband filtered multi-carrier system. The subband filtering implementations and both asynchronous and generalized synchronous (GS) MS subband filtered multi-carrier (SFMC) systems have been proposed. Based on the GS-MS-SFMC system, the system model with ISBI is derived and a number of properties on ISBI are given. In addition, low-complexity ISBI cancelation algorithms are proposed by precoding the information symbols at the transmitter. For asynchronous MS-SFMC system in the presence of transceiver imperfections, including carrier frequency offset, timing offset, and phase noise, a complete analytical system model is established in terms of desired signal, inter-symbol-interference, inter-carrier-interference, ISBI, and noise. Thereafter, new channel equalization algorithms are proposed by considering the errors and imperfections. Numerical analysis shows that the analytical results match the simulation results, and the proposed ISBI cancelation and equalization algorithms can significantly improve the system performance in comparison with the existing algorithms.
Autors: Lei Zhang;Ayesha Ijaz;Pei Xiao;Atta Quddus;Rahim Tafazolli;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Mar 2017, volume: 16, issue:3, pages: 1893 - 1907
Publisher: IEEE
 
» Submillimolar Detection of Adenosine Monophosphate Using Graphene-Based Electrochemical Aptasensor
Abstract:
In this paper, we present a successful demonstration of a graphene-based field-effect-transistor-like electrochemical nanobiosensor to accurately detect ultralow concentrations of adenosine monophosphate (AMP). Graphene being a two-dimensional material is a suitable option as a sensing element due to its biocompatibility and large surface area. It has also demonstrated surface binding chemistries as well as its ability to serve as a conducting channel. A short 20-base deoxyribonucleic acid (DNA) aptamer is used as the sensing element to ensure that the interaction between the analyte and the aptamer occurs within the Debye length of the electrolyte. The sensor is found to be nonlinear in nature and sensitive in the picomolar (pM) and nanomolar (nM) concentrations of AMP. The linear region of operation is found to be 1 nM–100 μM and percentage change in drain current in this concentration region is calculated as . A minimum concentration of 10 pM of AMP has been detected using this type of sensor.
Autors: Debopam Datta;Xenia Meshik;Souvik Mukherjee;Ketaki Sarkar;Min S. Choi;Mojgan Mazouchi;Sidra Farid;Yung Yu Wang;Peter John Burke;Mitra Dutta;Michael A. Stroscio;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Mar 2017, volume: 16, issue:2, pages: 196 - 202
Publisher: IEEE
 
» Subresolution Displacements in Finite Difference Simulations of Ultrasound Propagation and Imaging
Abstract:
Time domain finite difference simulations are used extensively to simulate wave propagation. They approximate the wave field on a discrete domain with a grid spacing that is typically on the order of a tenth of a wavelength. The smallest displacements that can be modeled by this type of simulation are thus limited to discrete values that are integer multiples of the grid spacing. This paper presents a method to represent continuous and subresolution displacements by varying the impedance of individual elements in a multielement scatterer. It is demonstrated that this method removes the limitations imposed by the discrete grid spacing by generating a continuum of displacements as measured by the backscattered signal. The method is first validated on an ideal perfect correlation case with a single scatterer. It is subsequently applied to a more complex case with a field of scatterers that model an acoustic radiation force-induced displacement used in ultrasound elasticity imaging. A custom finite difference simulation tool is used to simulate propagation from ultrasound imaging pulses in the scatterer field. These simulated transmit–receive events are then beamformed into images, which are tracked with a correlation-based algorithm to determine the displacement. A linear predictive model is developed to analytically describe the relationship between element impedance and backscattered phase shift. The error between model and simulation is , where is the acoustical wavelength. An iterative method is also presented that reduces the simulation error to over one iteration. The proposed technique therefore offers a computationally efficient method to model continuous subresolution displacements - f a scattering medium in ultrasound imaging. This method has applications that include ultrasound elastography, blood flow, and motion tracking. This method also extends generally to finite difference simulations of wave propagation, such as electromagnetic or seismic waves.
Autors: Gianmarco F. Pinton;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Mar 2017, volume: 64, issue:3, pages: 537 - 543
Publisher: IEEE
 
» Subscriber-Driven Interference Detection for Cloud-Based Web Services
Abstract:
Web services are now increasingly being hosted on public cloud infrastructure as a service platforms such as the Amazon Web service elastic compute cloud (EC2). However, previous studies have shown that the virtualized infrastructure used in public clouds can introduce contention among virtual machines (VMs) for shared physical host resources eventually leading to performance problems. Subscribers in a public cloud platform typically do not have access to metrics that can directly quantify the adverse impact of such inter-VM interference on Web service response times. We present a software probe based system to address this limitation. The probe is a lightweight application that runs on each Web service VM that needs to be monitored. We periodically measure the probe’s response time on a monitored VM. We then compare this response time with the probe’s previously recorded baseline no-interference response time when it executes in isolation on a VM of the same type. Statistically significant increase in the probe’s response time from the baseline is used to detect interference. The probe also indicates the type of contention at the physical host that causes the interference. This information can be exploited by a subscriber to mitigate the problem. Results show that our approach is quite effective over two different cloud platforms and a wide variety of workload scenarios. In particular, results indicate that Web service instances hosted on EC2 suffer from interference. Our probe was able to detect 93% of performance degradations triggered by such interference. In all these cases, the probe imposed an average overhead of only 3%–4% on the mean response time of the Web service being monitored.
Autors: Joydeep Mukherjee;Diwakar Krishnamurthy;Mea Wang;
Appeared in: IEEE Transactions on Network and Service Management
Publication date: Mar 2017, volume: 14, issue:1, pages: 48 - 62
Publisher: IEEE
 
» Superjunction Power Devices, History, Development, and Future Prospects
Abstract:
Superjunction has arguably been the most creative and important concept in the power device field since the introduction of the insulated gate bipolar transistor (IGBT) in the 1980s. It is the only concept known today that has challenged and ultimately proved wrong the well-known theoretical study on the limit of silicon in high-voltage devices. This paper deals with the history, device and process development, and the future prospects of Superjunction technologies. It covers fundamental physics, technological challenges as well as aspects of design and modeling of unipolar devices, such as CoolMOS. The superjunction concept is compared to other methods of enhancing the conductivity of power devices (from bipolar to employment of wide-bandgap materials) to derive its set of benefits and limitations. This paper closes with the application of the superjunction concept to other structures or materials, such as terminations, superjunction IGBTs, or silicon carbide Field Effect Transistors (FETs).
Autors: Florin Udrea;Gerald Deboy;Tatsuhiko Fujihira;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 720 - 734
Publisher: IEEE
 
» Surface Plasmon Polaritons Propagation Along Armchair and Zigzag Single-Wall Carbon Nanotubes With Different Radii
Abstract:
In this paper, we have studied chirality dependent optical properties of single-wall carbon nanotubes (CNTs), such as dynamic conductance and permittivity functions in THz, IR, and optical telecommunication bands. It is observed that CNTs with different radii yield different permittivity functions. We have presented the effects of phenomenological relaxation frequency, longitudinal surface plasmon resonance, and hybridization of π-orbitals on optical traits of armchair and zigzag CNTs. After their characterization, single-wall CNTs are utilized for guiding plasmonic surface modes, each is frequency dependent on its geometrical dimensions. It is demonstrated that surface plasmon polaritons can be excited along metallic nanotubes with very small radii. It is also revealed that as one choose the nanotube with smaller radius the propagation length and surface plasma frequency of that nanotube increase. The confinement of these modes and also their propagation length are studied and it is found that CNTs could become an excellent candidate for ultrathin plasmonic waveguides.
Autors: Sina Soleymani;Saeed Golmohammadi;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Mar 2017, volume: 16, issue:2, pages: 307 - 314
Publisher: IEEE
 
» Surface Texture Parameters of Perpendicular Magnetic Recording Disks
Abstract:
This paper presents the measured values of the surface texture parameters of commercially available perpendicular magnetic disks produced by five different vendors. In addition to the ordinary roughness parameter values, the asperity parameter values necessary for evaluating the mechanical characteristics of a head–disk interface with a clearance of less than 1 nm are evaluated. The mean asperity height is found to be 0.49 nm and the asperity density is 5044 . The asperity radius of curvature has an anisotropic nature, but its average value is approximately 20 nm. However, the peak radius of the highest asperity group associated with the asperity contact is close to 10 nm.
Autors: Kyosuke Ono;
Appeared in: IEEE Transactions on Magnetics
Publication date: Mar 2017, volume: 53, issue:3, pages: 1 - 6
Publisher: IEEE
 
» Sustainable Incentive Mechanisms for Mobile Crowdsensing: Part 1
Abstract:
Autors: Linghe Kong;Kui Ren;Muhammad Khurram Khan;Qi Li;Ammar Rayes;Merouane Debbah;Yuichi Nakamura;
Appeared in: IEEE Communications Magazine
Publication date: Mar 2017, volume: 55, issue:3, pages: 60 - 61
Publisher: IEEE
 
» Sustainable Incentives for Mobile Crowdsensing: Auctions, Lotteries, and Trust and Reputation Systems
Abstract:
Proper incentive mechanisms are critical for mobile crowdsensing systems to motivate people to actively and persistently participate. This article provides an exposition of design principles of six incentive mechanisms, drawing special attention to the sustainability issue. We cover three primary classes of incentive mechanisms: auctions, lotteries, and trust and reputation systems, as well as three other frameworks of promising potential: bargaining games, contract theory, and market- driven mechanisms.
Autors: Tie Luo;Salil S. Kanhere;Jianwei Huang;Sajal K. Das;Fan Wu;
Appeared in: IEEE Communications Magazine
Publication date: Mar 2017, volume: 55, issue:3, pages: 68 - 74
Publisher: IEEE
 
» Symbol Misalignment Estimation in Asynchronous Physical-Layer Network Coding
Abstract:
Symbol misalignment is inevitable in asynchronous physical-layer network coding (PNC) systems. It is paramount that such symbol misalignment is taken into account in PNC decoding for good performance. Thus, accurate estimation of symbol misalignment is crucial. This paper argues that, when Nyquist pulses (i.e., intersymbol-interference (ISI)-free pulses) are adopted, signal samples only need to be collected at baud rate for optimal symbol misalignment estimation. Based on this principle, we propose a highly accurate symbol misalignment estimation method with low complexity. Our method makes use of the constant amplitude zero autocorrelation sequence (Zadoff–Chu sequence (ZC sequence)). We derive a maximum-likelihood (ML) estimator for symbol misalignment based on the cross-correlation result of the ZC sequence. Unlike previous methods that employ oversampling, our estimation method requires only baud-rate sampling, thus having much lower complexity. Extensive simulations show that our method can accurately estimate both integral and fractional symbol misalignments using sinc pulse and raised-cosine (RC) pulse. The root-mean-square error (RMSE) of the estimation is below 10−2 (in unit of symbol duration) when the SNR is above 15, 18, and 21 dB for 127-, 63-, and 31-bit-length ZC sequences, respectively. Furthermore, our method, being an ML estimation method, has no error floor in the high-SNR regime, whereas the prior methods exhibit an error floor.
Autors: Qing Yang;Soung Chang Liew;Lu Lu;Yulin Shao;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Mar 2017, volume: 66, issue:3, pages: 2844 - 2852
Publisher: IEEE
 
» Symmetric U-Shaped Gate Tunnel Field-Effect Transistor
Abstract:
A novel heterojunction symmetric U-shaped gate tunnel FET (SUTFET) is proposed and investigated by Silvaco Atlas simulation. The U-shaped gate in the SUTFET can enlarge the area of the tunneling junction and facilitate the implementation of a smaller device area. Benefit from the line band-to-band tunneling process and symmetric structure design, bidirectional current flows (, pA/ at V) with the steep-switching feature of subthreshold slope (SS mV/decade at V and average SS mV/decade from 0 V < VGS < 0.05 V) are implemented. The effects of doping concentration and geometric dimensions on the device performance are investigated in order to create the SUTFET design guideline. The considerable good performance of the SUTFET makes it very attractive for ultralow-power applications.
Autors: Shupeng Chen;Shulong Wang;Hongxia Liu;Wei Li;Qianqiong Wang;Xing Wang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Mar 2017, volume: 64, issue:3, pages: 1343 - 1349
Publisher: IEEE
 
» Synergistic Approximation of Computation and Memory Subsystems for Error-Resilient Applications
Abstract:
Approximate computing is a new design paradigm that exploits the intrinsic error resilience exhibited by emerging applications to significantly improve their energy efficiency and performance. Prior work in this domain has proposed approximation techniques targeting either the computational subsystem or the memory subsystem. For the first time, this letter proposes a methodology to perform synergistic approximations across the computation and memory subsystems together that results in a significant improvement in energy consumption compared to the case when the subsystems are approximated independently. We implemented our proposed methodology using an Altera Stratix IV GX FPGA based Terasic TR4-230 development board containing a 1GB DDR3 DRAM module, which executes three error-resilient benchmarks. Experimental results demonstrate energy improvements in the range of - for minimal loss in application quality (<1%). Compared to individual approximations, our technique achieves an additional - energy savings for the same quality specifications.
Autors: Arnab Raha;Vijay Raghunathan;
Appeared in: IEEE Embedded Systems Letters
Publication date: Mar 2017, volume: 9, issue:1, pages: 21 - 24
Publisher: IEEE
 
» Synthesis of Cross-Coupled Filters With Frequency-Dependent Couplings
Abstract:
This paper presents a novel synthesis technique for coupled-resonator filters with frequency-dependent couplings. Unlike the works so far appeared in the literature, the proposed technique is not based on the optimization of a network with assigned topology, but it consists in the explicit synthesis of a folded prototype with frequency-dependent transversal couplings. The proposed procedure starts with the synthesis of a new type of canonical prototype with frequency-invariant couplings (the asymmetric lattice); this prototype is then suitably transformed by means of scaling and rotations of coupling and capacitance matrices for obtaining the new configuration with frequency-dependent couplings. Concerning the asymmetric lattice prototype, we show how this canonical network degenerates, in a special case, into the cul-de-sac form; this happens when the assigned reflection zeros are imaginary (or in pairs with opposite real part). This also implies that cul-de-sac is admissible only when reflection zeros satisfy this condition. The novel synthesis approach is illustrated with several examples. A test diplexer employing filters with frequency-dependent couplings has been designed and fabricated for validating the novel synthesis approach.
Autors: Stefano Tamiazzo;Giuseppe Macchiarella;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Mar 2017, volume: 65, issue:3, pages: 775 - 782
Publisher: IEEE
 
» Synthesis of probabilistic fuzzy classifiers using GK clustering and Bayesian estimation
Abstract:
The paper presents an automatic rule-base design of probabilistic fuzzy systems developed for classification tasks. The objective here is to present a methodology that allows the user to obtain a fuzzy classifier directly from training data, in which rules' antecedents are defined on the basis of clustering techniques and probabilistic consequents allow the presence of all classes in the same individual rule, each class associated with a measure of probability. The probability measure is calculated based on Bayes' theorem using an ideal region of the rule to update a priori information. The clustering process which supports the automatic partition of the input universe is based on the Gustafson-Kessel algorithm and is associated with a principal component analysis to reduce the dimensionality of the input data, improving this way the interpretability of the resulting classifier. The proposed approach is applied to Wine, Wisconsin breast cancer, Sonar e Ionosphere data sets. Results are compared with those of two other classifiers and show that the proposed approach can be an alternative to automatically set antecedents and consequents of probabilistic fuzzy classifiers.
Autors: Luiz Ledo;Myriam Regattieri Delgado;Jose Valente de Oliveira;
Appeared in: IEEE Latin America Transactions
Publication date: Mar 2017, volume: 15, issue:3, pages: 550 - 556
Publisher: IEEE
 

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