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Electrical and Electronics Engineering publications abstract of: 01-2017 sorted by title, page: 10

» Resource Allocation for Virtualized Wireless Networks with Backhaul Constraints
Abstract:
In this letter, we study resource allocation for wireless virtualized networks considering both the backhaul capacity of the infrastructure provider (InP) and the users’ quality-of-service (QoS) requirements. We focus on the profit gained by a mobile virtual network operator (MVNO), which is a middleman who buys physical resource from the InP, bundling them into virtual resources called slides before selling off the service providers. The objective of the MVNO is to maximize its profit while guaranteeing the backhaul constraint and users’ QoS by jointly allocating the slices and the uplink transmit power to the users. To solve the formulated mixed integer non-convex problem, we propose a distributed solution framework based on Lagrangian relaxation to a find suboptimal decision about slice and transmit power allocations. We further propose a low-complexity solution based on the concept of a matching game that does not require any global information. Numerical results are provided to evaluate the performance of the proposed schemes.
Autors: Tuan LeAnh;Nguyen H. Tran;Duy Trong Ngo;Choong Seon Hong;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 148 - 151
Publisher: IEEE
 
» Response Characteristics of Coaxial Capacitance Sensor for Horizontal Segregated and Non-Uniform Oil-Water Two-Phase Flows
Abstract:
In this paper, the response characteristics of a coaxial capacitance sensor for horizontal oil-water two-phase flows with segregated and non-uniform phase distribution are investigated. First, the experiment of horizontal oil-water two-phase flow is carried out in a 20-mm inner diameter pipe with a flow concentration device. The response signals of the coaxial capacitance sensor under different flow patterns are collected by a data acquisition device. Meanwhile, the liquid holdup is measured using three pairs of parallel-wire capacitance probes and quick closing valve technology to uncover the complex slippage behaviors between phases. Then, the effects of the flow slippage and non-uniform phase distribution on the sensor response characteristics are investigated based on the equivalent impedance circuit analysis and adaptive optimal kernel time-frequency representation. In general, the results show that the coaxial capacitance sensor presents preferable response resolution for selected horizontal oil-water two-phase flow patterns, such as stratified flow and stratified flow with mixing at interface. However, as the flow pattern evolves to dispersed oil-in-water and water flow with high water-cut, the response resolution of the coaxial capacitance sensor is lower.
Autors: Hongxin Zhang;Lusheng Zhai;Yunfeng Han;Xuan Chen;Zhongke Gao;Ningde Jin;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 359 - 368
Publisher: IEEE
 
» Reviewers and Editors Appreciation 2016
Abstract:
On behalf of the Editorial Board, I would like to thank all our reviewers for their effort and dedication. As has already become customary, at the beginning of each year we recognize reviewers for their sustained and outstanding review contributions. The list of 2016 exemplary reviewers is provided below.
Autors: Octavia A. Dobre;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 3 - 3
Publisher: IEEE
 
» RF Passive Components Based on Aluminum Nitride Cross-Sectional Lamé-Mode MEMS Resonators
Abstract:
This paper presents a new class of monolithic integrated RF passive components based on the recently developed aluminum nitride (AlN) MEMS cross-sectional Lamé-mode resonator (CLMR) technology. First, we experimentally demonstrate a 920-MHz CLMR showing the values of electromechanical coupling coefficient () and quality factor () in excess of 6.2% and 1750, respectively. To the best our knowledge, the resulting figure of merit (), in excess of 108, is the highest ever reported for AlN-based piezoelectric resonators using interdigitated metallic electrodes (IDTs) and operating in the same frequency range. Second, we report the measured performance of an 870-MHz ladder filter, synthesized using three degenerate CLMRs. This device shows the values of fractional bandwidth (BW) in excess of 3.8% and an insertion loss of ~1.5 dB. Finally, we report the performance of the first piezoelectric transformer (PT) based on the CLMR technology. This device, dubbed “cross-sectional Lamé-mode transformer,” exploits the high- of the CLMR technology to achieve high values of open-circuit voltage-gains () in excess of 39. To the best of our knowledge, such a high -value is the highest ever reported for MEMS-based PTs operating in the- microwave frequency range.
Autors: Cristian Cassella;Guofeng Chen;Zhenyun Qian;Gwendolyn Hummel;Matteo Rinaldi;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 237 - 243
Publisher: IEEE
 
» RF Power Analysis on 5.8 GHz Low-Power Amplifier Using Resonant Tunneling Diodes
Abstract:
This letter reports the analysis of RF power characteristics in a microwave amplifier using resonant tunneling diodes (RTDs). The implemented IC shows a return loss of more than 11 dB with a low dc-power consumption of 0.42 mW and a power gain of 8.6 dB at 5.8 GHz. The maximum linear RF output power with a uniform gain of 8.6 dB is measured to be −25.4 dBm at the same frequency. The gain hump phenomenon is observed in an input power range from −32 dBm to −16 dBm, and is shown to arise from a sudden movement of the operating point from the negative differential resistance (NDR) region to the positive differential resistance (PDR) region, based on a large-signal load-line analysis together with a harmonic balance simulation.
Autors: Jongwon Lee;Kyounghoon Yang;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2017, volume: 27, issue:1, pages: 61 - 63
Publisher: IEEE
 
» RF-MEMS Tuned GaN HEMT based Cavity Oscillator for X-band
Abstract:
This letter presents a radio frequency micro-electromechanical systems (RF-MEMS) tuned cavity oscillator for X-band. The active part of the oscillator is implemented in GaN-HEMT MMIC technology. The RF-MEMS-switches are realized on a quartz substrate that is surface mounted on a low loss PCB. The PCB is intruded in an aluminum cavity acting as an electrically moveable wall. For a three-row RF-MEMS setup, a tuning range of 5 % around an oscillation frequency of 10 GHz is demonstrated in measurements. The phase noise is as low as −140 dBc/Hz to −129 dBc/Hz at 100 kHz from the carrier, depending on the configuration of the RF-MEMS.
Autors: Mikael Hörberg;Thomas Emanuelsson;Per Ligander;Szhau Lai;Herbert Zirath;Dan Kuylenstierna;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Jan 2017, volume: 27, issue:1, pages: 46 - 48
Publisher: IEEE
 
» RFI Mitigation in Aperture Synthesis Radiometers Using a Modified CLEAN Algorithm
Abstract:
For aperture synthesis radiometers, sparse samplings on the - frequency plane cause undesirable sidelobes in the synthesized beam. Through these sidelobes, artificial sources emitting in the protected 1400–1427 MHz band contaminate the retrievals of the soil moisture and ocean salinity (SMOS) from MIRAS measurements. One effective way to correct the artificial interferences is to create a synthetic signal to compensate for the interference’s impact. Based on the similar idea, in this letter, we describe an algorithm to compensate for the interference’s impact by constructing an artificial signal as close as possible to the Gaussian beam. Numerical studies using synthetic and real SMOS data have been carried out to demonstrate that the proposed algorithm outperforms the classical CLEAN algorithm in correcting the impact of the extended radio frequency interference source.
Autors: Fei Hu;Xiaohui Peng;Feng He;Liang Wu;Jun Li;Yayun Cheng;Dong Zhu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 13 - 17
Publisher: IEEE
 
» Road Vibrations as a Source to Detect the Presence and Speed of Vehicles
Abstract:
The study of vehicular traffic is essential for modern cities to determine the efficiency of their current roads and to plan new infrastructure that keeps the mobility of its inhabitants. Technologies that provide detailed data of the current situation on the roads are needed to reduce journey times and pollution emissions and consequently improve the quality of life of the people. Smart streets featuring sensor networks offer the possibility to study with high accuracy the traffic conditions on every point of the road. Using sensor networks parameters like speed, travel direction, and type of vehicles can be precisely calculated. Furthermore, it is possible to determine in real time the peak hours and the site of accidents. Different sources such as sound, magnetism, or vibrations can be used to monitor the traffic flow. From them, road vibrations are of special interest because of their potential for energy harvesting by using piezoelectric films and thus reducing the dependence on external power sources. This paper presents a study that provides the bases to develop a 2-D sensor network using MEMS accelerometers placed on the width and length of the road surface to monitor continuously the traffic flow. In this paper, piezoelectric acceleration sensors, based on the same measuring principle as MEMS accelerometers, are used with the objective to analyze in detail the amplitudes and frequency ranges in which vibrations occur. From this information, the algorithms to determine the presence of vehicles, their travel direction, and speed are developed.
Autors: Javier Rivas;Ralf Wunderlich;Stefan J. Heinen;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 377 - 385
Publisher: IEEE
 
» Robotic Room-Level Localization Using Multiple Sets of Sonar Measurements
Abstract:
In this paper, we aim to achieve robust and cost-effective room-level localization for the indoor mobile robot. It is unrealistic to obtain precise localization information from the sonar sensors because of the sparseness and uncertainty. Our attempts show that the room-level localization can be achieved using sonar sensors by accumulating the sonar data to overcome the limitations of sensor performance. To this end, we formulate the room-level localization as a joint sparse coding problem, which encourages the coding vectors to share the common room sparsity, but different locations. We systematically evaluate the performance of the different coding strategies on the collected sonar measurement data set.
Autors: Huaping Liu;Fuchun Sun;Bin Fang;Xinyu Zhang;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jan 2017, volume: 66, issue:1, pages: 2 - 13
Publisher: IEEE
 
» Robust Adaptive Fault-Tolerant Control for a Class of Unknown Nonlinear Systems
Abstract:
This paper studies the fault-tolerant tracking control problem for a class of strict-feedback nonlinear systems subjected to actuator faults and external disturbances. The prior knowledge for actuator fault, nonlinearity, and external disturbance is totally unknown, besides the control directions. Based on a backstepping approach, an adaptive fault-tolerant control scheme is developed, without utilizing neural networks. In the control design, a group of new feedback mechanisms are proposed to compensate for the unknown system dynamics and actuator faults. Furthermore, to relax a requirement of the initial system states, a modification technique is designed to adjust the reference signal and virtual control laws for a short time. It is shown that the global closed-loop stability is guaranteed and the tracking performance is achieved. The above result is illustrated via simulations on a one-link manipulator and a ship autopilot.
Autors: Jin-Xi Zhang;Guang-Hong Yang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 585 - 594
Publisher: IEEE
 
» Robust Global Trajectory Tracking for Underactuated VTOL Aerial Vehicles Using Inner-Outer Loop Control Paradigms
Abstract:
This paper proposes a feedback control strategy to let the dynamics of a class of under-actuated vertical take-off and landing (VTOL) aerial vehicle tracking a desired position and attitude trajectory globally with respect to the initial conditions. The proposed feedback controller is derived following an inner-outer loop control paradigm, namely by considering the attitude, which is governed by means of a hybrid controller so as to overcome the well-known topological constraints, serving as a virtual input to stabilize the aircraft position. Two different approaches, the first one obtained by assuming perfect knowledge of the vehicle dynamics and the second one obtained by considering uncertainties and exogenous disturbances, are proposed and compared by analyzing the interconnection between the hybrid attitude and the continuous-time position closed-loop subsystems. The effectiveness of the obtained results is demonstrated by means of simulations and experiments using a miniature quadrotor prototype.
Autors: Roberto Naldi;Michele Furci;Ricardo G. Sanfelice;Lorenzo Marconi;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 97 - 112
Publisher: IEEE
 
» Robust Output Regulation of Strongly Passive Linear Systems With Multivalued Maximally Monotone Controls
Abstract:
The use of multivalued controls derived from a special maximally monotone operator are studied in this paper. Starting with a strongly passive linear system (with possible parametric uncertainty and external disturbances) a multivalued control law is derived, ensuring regulation of the output to a desired value. The methodology used falls in a passivity-based control context, where we study how the multivalued control affects the dissipation equation of the closed-loop system, from which we derive its robustness properties. Finally, some numerical examples together with implementation issues are presented to support the main result.
Autors: Félix A. Miranda-Villatoro;Fernando Castaños;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 238 - 249
Publisher: IEEE
 
» Robust Partial Feedback Linearizing Excitation Controller Design for Multimachine Power Systems
Abstract:
This paper presents a new robust nonlinear excitation controller design for synchronous generators in multimachine power systems to enhance the transient stability. The mismatches between the original power system model and formulated mathematical model are considered as uncertainties, which are modeled through the satisfaction of matching conditions. The exogenous noises appearing from measurements are incorporated with the power system model including the two-axis model of synchronous generators. The partial feedback linearization technique is used to design the controller which transforms the original nonlinear multimachine power system model into several reduced-order linear and autonomous subsystems. The desired control law is obtained for each subsystem and implemented in a decentralized manner provided that the dynamics of the autonomous subsystems have no effects on the overall stability of the system. The analysis related to the dynamics of noisy autonomous subsystems is also included and the proposed controller has the excellent capability to decouple these noises. Finally, the performance of the proposed control scheme is evaluated on an IEEE 39-bus benchmark power system following different types of large disturbances. The performance of the proposed controller is compared to that of a partial feedback linearizing controller, which is designed without robustness properties, to verify the effectiveness of the proposed control scheme.
Autors: M. A. Mahmud;M. J. Hossain;H. R. Pota;Amanullah M. T. Oo;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 3 - 16
Publisher: IEEE
 
» Robust Risk-Constrained Unit Commitment With Large-Scale Wind Generation: An Adjustable Uncertainty Set Approach
Abstract:
This paper addresses two vital issues which are barely discussed in the literature on robust unit commitment (RUC): 1) how much the potential operational loss could be if the realization of uncertainty is beyond the prescribed uncertainty set; 2) how large the prescribed uncertainty set should be when it is used for RUC decision making. In this regard, a robust risk-constrained unit commitment (RRUC) formulation is proposed to cope with large-scale volatile and uncertain wind generation. Differing from existing RUC formulations, the wind generation uncertainty set in RRUC is adjustable via choosing diverse levels of operational risk. By optimizing the uncertainty set, RRUC can allocate operational flexibility of power systems over spatial and temporal domains optimally, reducing operational cost in a risk-constrained manner. Moreover, since impact of wind generation realization out of the prescribed uncertainty set on operational risk is taken into account, RRUC outperforms RUC in the case of rare events. The traditional column and constraint generation (C&CG) and two algorithms based on C&CG are adopted to solve the RRUC. As the proposed algorithms are quite general, they can also apply to other RUC models to improve their computational efficiency. Simulations on a modified IEEE 118-bus system demonstrate the effectiveness and efficiency of the proposed methodology.
Autors: Cheng Wang;Feng Liu;Jianhui Wang;Feng Qiu;Wei Wei;Shengwei Mei;Shunbo Lei;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 723 - 733
Publisher: IEEE
 
» Robust Shrinkage Normalized Sign Algorithm in an Impulsive Noise Environment
Abstract:
In this brief, a robust shrinkage normalized sign (RSHNS) algorithm is presented, which uses an optimal step size by minimizing the energy of the noise-free a posteriori error signal and using Price's theorem. To reduce the impact of impulsive noise, the noise-free error signal is estimated by using the robust shrinkage method. It uses two threshold parameters as compared to that in the conventional shrinkage method. Finally, the improved convergence performance of the proposed RSHNS algorithm is demonstrated through simulation results in system identification and echo-cancellation applications.
Autors: Sheng Zhang;Jiashu Zhang;Hongyu Han;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jan 2017, volume: 64, issue:1, pages: 91 - 95
Publisher: IEEE
 
» Robust Sparse Coding for Mobile Image Labeling on the Cloud
Abstract:
With the rapid development of the mobile service and online social networking service, a large number of mobile images are generated and shared on the social networks every day. The visual content of these images contains rich knowledge for many uses, such as social categorization and recommendation. Mobile image labeling has, therefore, been proposed to understand the visual content and received intensive attention in recent years. In this paper, we present a novel mobile image labeling scheme on the cloud, in which mobile images are first and efficiently transmitted to the cloud by Hamming compressed sensing, such that the heavy computation for image understanding is transferred to the cloud for quick response to the queries of the users. On the cloud, we design a sparse correntropy framework for robustly learning the semantic content of mobile images, based on which the relevant tags are assigned to the query images. The proposed framework (called maximum correntropy-based mobile image labeling) is very insensitive to the noise and the outliers, and is optimized by a half-quadratic optimization technique. We theoretically show that our image labeling approach is more robust than the squared loss, absolute loss, Cauchy loss, and many other robust loss function-based sparse coding methods. To further understand the proposed algorithm, we also derive its robustness and generalization error bounds. Finally, we conduct experiments on the PASCAL VOC’07 data set and empirically demonstrate the effectiveness of the proposed robust sparse coding method for mobile image labeling.
Autors: Dapeng Tao;Jun Cheng;Xinbo Gao;Xuelong Li;Cheng Deng;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Jan 2017, volume: 27, issue:1, pages: 62 - 72
Publisher: IEEE
 
» Robust Stabilization of a Wheeled Mobile Robot Using Model Predictive Control Based on Neurodynamics Optimization
Abstract:
In this paper, a robust model predictive control (MPC) scheme using neural network-based optimization has been developed to stabilize a physically constrained mobile robot. By applying a state-scaling transformation, the intrinsic controllability of the mobile robot can be regained by incorporation into the control input an additional exponential decaying term. An MPC-based control method is then designed for the robot in the presence of external disturbances. The MPC optimization can be formulated as a convex nonlinear minimization problem and a primal–dual neural network is adopted to solve this optimization problem over a finite receding horizon. The computational efficiency of MPC has been improved by the proposed neurodynamic approach. Experimental studies under various dynamic conditions have been performed to demonstrate the performance of the proposed approach.
Autors: Hanzhen Xiao;Zhijun Li;Chenguang Yang;Lixian Zhang;Peijiang Yuan;Liang Ding;Tianmiao Wang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 505 - 516
Publisher: IEEE
 
» Robust Ultra-High Resolution Microwave Planar Sensor Using Fuzzy Neural Network Approach
Abstract:
In this paper, we develop a robust and fault-tolerant approach to microwave-based sensitive measurements using fuzzy neural network (FNN). Microwave chemic-identification, recently, is employing active planar ring resonators to enhance the resolutions significantly. However, in practice, when the technology of resolution improves, the results become more prone to minor variations in the measurement setup and user error. In order to eliminate these unwanted and uncontrollable deviations from the final allocations, we propose a novel and robust approach that uses more than one parameter out of measurements and incorporates FNN as a machine learning architecture at the post processing stage of sensing to obtain fault-tolerant classification. We have compared different membership functions used in the FNN and shown improvement in assigning accuracy from 49% (single parameter-dependent) up to 81.5% (three parameters-dependent) on an average of four materials, such as isopropanol-2 (IPA), ethanol, acetone, and water.
Autors: Mohammad Abdolrazzaghi;Mohammad Hossein Zarifi;Witold Pedrycz;Mojgan Daneshmand;
Appeared in: IEEE Sensors Journal
Publication date: Jan 2017, volume: 17, issue:2, pages: 323 - 332
Publisher: IEEE
 
» Room-Temperature Single-Photon Detection With 1.5-GHz Gated InGaAs/InP Avalanche Photodiode
Abstract:
A room-temperature single-photon detector was demonstrated with InGaAs/InP avalanche photodiode (APD) with negligible afterpulse effect and low dark count rates. The APD was operated in 1.5-GHz sinusoidally gated Geiger mode by using appropriate low-pass filters to minimize the capacitive spike noises. A detection efficiency of ~21% was attained with the dark count rate of per gate and a afterpulse probability of 1.4%, showing excellent performance without cooling. Moreover, we varied the amplitude of the sinusoidal gates to further optimize the performance. The room-temperature single-photon detectors with compact structures and low power consumption offer advantages in practical quantum key distribution and ultra-distance laser ranging systems.
Autors: Yan Liang;Yuanjin Chen;Zinan Huang;Guomin Bai;Min Yu;Heping Zeng;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 142 - 145
Publisher: IEEE
 
» Root Sparse Bayesian Learning for Off-Grid DOA Estimation
Abstract:
The performance of the existing sparse Bayesian learning (SBL) methods for off-grid direction-of-arrival (DOA) estimation is dependent on the tradeoff between the accuracy and the computational workload. To speed up the off-grid SBL method while remain a reasonable accuracy, this letter describes a computationally efficient root SBL method for off-grid DOA estimation, which adopts a coarse grid and considers the sampled locations in the coarse grid as the adjustable parameters. We utilize an expectation–maximization algorithm to iteratively refine this coarse grid and illustrate that each updated grid point can be simply achieved by the root of a certain polynomial. Simulation results demonstrate that the computational complexity is significantly reduced, and the modeling error can be almost eliminated.
Autors: Jisheng Dai;Xu Bao;Weichao Xu;Chunqi Chang;
Appeared in: IEEE Signal Processing Letters
Publication date: Jan 2017, volume: 24, issue:1, pages: 46 - 50
Publisher: IEEE
 
» Rotor Configurations for Improved Starting and Synchronous Performance of Line Start Permanent-Magnet Synchronous Motor
Abstract:
This paper presents two new rotor configurations for the line start permanent-magnet synchronous motors (PMSMs). The first configuration proposed here uses inset consequent magnet pole arrangement with double cage, and results into improved starting performance when compared to the other rotor configurations previously used. The second configuration proposed uses a combination of circumferentially and radially magnetized magnets (hybrid rotor), with induced magnet poles, which results into improved synchronous performance. Two-dimensional finite-element analysis has been employed in the analysis of transient and steady-state performances. The experimental prototypes for the second configuration are built and tested extensively. To demonstrate the effectiveness of the hybrid rotor configuration, an additional prototype is made that employs the circumferentially magnetized magnets (spoke magnet type rotor), and performance of the proposed rotor is benchmarked with this. Analysis, simulation, and experimental results indicate that the proposed rotor configuration leads to improved steady-state performance, by utilizing 10% less magnet volume than the benchmarked spoke rotor. The proposed configurations are also suitable for inverter-fed brushless dc, and PMSMs.
Autors: R. T. Ugale;B. N. Chaudhari;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 138 - 148
Publisher: IEEE
 
» Rough-Set-Based Color Channel Selection
Abstract:
Color channel selection is essential for accurate segmentation of sky and clouds in images obtained from ground-based sky cameras. Most prior works in cloud segmentation use threshold-based methods on color channels selected in an ad hoc manner. In this letter, we propose the use of rough sets for color channel selection in visible-light images. Our proposed approach assesses color channels with respect to their contribution for segmentation and identifies the most effective ones.
Autors: Soumyabrata Dev;Florian M. Savoy;Yee Hui Lee;Stefan Winkler;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 52 - 56
Publisher: IEEE
 
» Round-Trip Energy Efficiency of Wireless Energy Powered Massive MIMO System With Latency Constraint
Abstract:
We consider a massive MIMO system with frequency-division duplex, where a base station (BS) transfers energy to multiple users in the downlink and the users simultaneously transmit information to the BS in the uplink using the harvested energy. The objective of this letter is to optimize the round-trip energy efficiency (EE) by transmit power allocation at the BS while guaranteeing the delay outage requirements of different users with Poisson traffic arrivals. The service rate and the delay outage probability are first derived. Then, the power allocation problem is formulated as a non-convex problem, which is then transformed into a convex one. The results indicate that the proposed power allocation can significantly improve the round-trip EE of wireless energy powered massive MIMO system.
Autors: Long Zhao;Xiaodong Wang;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 12 - 15
Publisher: IEEE
 
» Running Stability of a Prototype Vehicle in a Side-Suspended HTS Maglev Circular Test Track System
Abstract:
To improve the running speed of the high-Tc superconductor (HTS) maglev system, a circular test track system with the maglev vehicle suspending beside the permanent magnetic guideway (PMG) is studied. A test to determine the change in guidance force when a YBa2Cu3O7 (YBCO) bulk gets close to and off the center of the PMG is carried out and the curve of relation between levitation gap and vertical eccentric displacement of the YBCO bulk under constant guidance force is obtained. The results show that eccentric motion in the vertical direction may occur during free side-suspended operation of the maglev vehicle in the circular track, which leads to a reduction in levitation gap and an increase in vertical eccentric displacement, decaying and enhancing the guidance force, respectively. Eccentric motion can be effectively restrained by reducing the field cooling height and the weight of the maglev vehicle to improve the running stability of the maglev vehicle. Finally, a circular test track 6.5 m in diameter and 20.4 m in length and a prototype vehicle are designed and constructed on the basis of the side-suspended HTS maglev system.
Autors: Dajin Zhou;Chenyu Cui;Lifeng Zhao;Yong Zhang;Xiqing Wang;Yong Zhao;
Appeared in: IEEE Transactions on Applied Superconductivity
Publication date: Jan 2017, volume: 27, issue:1, pages: 1 - 7
Publisher: IEEE
 
» RWiN: New Methodology for the Development of Reconfigurable WSN
Abstract:
This paper presents new challenges for the development of reconfigurable wireless sensor networks (RWSNs) that adapt dynamically their behaviors to their environment under different properties. An RWSN is a set of networked nodes that execute reconfigurable software tasks for the control of local sensors. We propose a new design methodology named RWiN of an RWSN using unified modeling language (UML) to analyze, construct, develop, and verify easily RWSN architectures. For that, we formulate a metamodel of RWSN based on UML to describe a zone-based architecture that uses a communication protocol for the optimization of distributed reconfigurations. To control the design complexity, we model each agent of this architecture by nested state machines. To verify the temporal constraints by communicating agents, each one is modeled by a timed automaton. The paper’s contribution is applied to a case study, which is simulated with TRMSim-WSN and UPPAAL environment to expose the originality of this new architecture.
Autors: Hanen Grichi;Olfa Mosbahi;Mohamed Khalgui;Zhiwu Li;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 109 - 125
Publisher: IEEE
 
» Safeguarding Decentralized Wireless Networks Using Full-Duplex Jamming Receivers
Abstract:
In this paper, we study the benefits of full-duplex (FD) receiver jamming in enhancing the physical-layer security of a two-tier decentralized wireless network with each tier deployed with a large number of pairs of a single-antenna transmitter and a multi-antenna receiver. In the underlying tier, the transmitter sends unclassified information and the receiver works in the half-duplex (HD) mode receiving the desired signal. In the overlaid tier, the transmitter delivers confidential information in the presence of randomly located eavesdroppers, and the receiver works in the FD mode radiating jamming signals to confuse eavesdroppers and receiving the desired signal simultaneously. We provide a comprehensive performance analysis and network design under a stochastic geometry framework. Specifically, we consider the scenarios where each FD receiver uses single- and multi-antenna jamming, and analyze the connection probability and the secrecy outage probability of a typical FD receiver by deriving accurate expressions and more tractable approximations for the two probabilities. We also determine the optimal deployment density of the FD-mode tier to maximize the network-wide secrecy throughput subject to constraints including the given dual probabilities and the network-wide throughput of the HD-mode tier. Numerical results are demonstrated to verify our theoretical findings, and show that the network-wide secrecy throughput is significantly improved by properly deploying the FD-mode tier.
Autors: Tong-Xing Zheng;Hui-Ming Wang;Qian Yang;Moon Ho Lee;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 278 - 292
Publisher: IEEE
 
» Sample-Based Attribute Selective A$n$ DE for Large Data
Abstract:
More and more applications have come with large data sets in the past decade. However, existing algorithms cannot guarantee to scale well on large data. Averaged n-Dependence Estimators (AnDE) allows for flexible learning from out-of-core data, by varying the value of (number of super parents). Hence, AnDE is especially appropriate for large data learning. In this paper, we propose a sample-based attribute selection technique for AnDE. It needs one more pass through the training data, in which a multitude of approximate AnDE models are built and efficiently assessed by leave-one-out cross validation. The use of a sample reduces the training time. Experiments on 15 large data sets demonstrate that the proposed technique significantly reduces AnDE's error at the cost of a modest increase in training time. This efficient and scalable out-of-core approach delivers superior or comparable performance to typical in-core Bayesian network classifiers.
Autors: Shenglei Chen;Ana M. Martínez;Geoffrey I. Webb;Limin Wang;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Jan 2017, volume: 29, issue:1, pages: 172 - 185
Publisher: IEEE
 
» Sampled-Time-Domain Analysis of a Digitally Implemented Current Controlled Inverter
Abstract:
This paper presents a sampled-time-domain analysis to investigate the sampling effect on instantaneous switching frequency of a digitally implemented hysteresis current control (HCC) in a voltage source inverter (VSI). The generalized expression of the instantaneous switching frequency with the consideration of sampling frequency has been derived. The effect of variation in sampling frequency on effective hysteresis band and switching frequency has been analyzed. The difference between maximum to minimum switching frequency of a fixed-band HCC VSI depends on the sampling frequency of the digital controller. The sampling also generates a steady-state tracking error exceeding the fixed-band limit at the fundamental frequency for fixed hysteresis band operation. The analysis has been done to achieve fixed switching frequency with variable hysteresis band and with varying sampling period. The frequency spectrum of the load current is presented to show the effect of a digital controller. The sampling effect on the switching performance has been demonstrated for a single-phase VSI under different loading conditions. To verify the analytical results, the simulation and experimental results are obtained with the current controller implemented on a field programmable gate array-based digital controller.
Autors: Mayank Kumar;Rajesh Gupta;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 217 - 227
Publisher: IEEE
 
» Sampling Rate Distortion
Abstract:
Consider a discrete memoryless multiple source with components of which possibly different sources are sampled at each time instant and jointly compressed in order to reconstruct all the sources under a given distortion criterion. A new notion of sampling rate distortion function is introduced, and is characterized first for the case of fixed-set sampling. Next, for independent random sampling performed without knowledge of the source outputs, it is shown that the sampling rate distortion function is the same regardless of whether or not the decoder is informed of the sequence of sampled sets. Furthermore, memoryless random sampling is considered with the sampler depending on the source outputs and with an informed decoder. It is shown that deterministic sampling, characterized by a conditional point-mass, is optimal and suffices to achieve the sampling rate distortion function. For memoryless random sampling with an uninformed decoder, an upper bound for the sampling rate distortion function is seen to possess a similar property of conditional point-mass optimality. It is shown by example that memoryless sampling with an informed decoder can outperform strictly any independent random sampler, and that memoryless sampling can do strictly better with an informed decoder than without.
Autors: Vinay Praneeth Boda;Prakash Narayan;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 563 - 574
Publisher: IEEE
 
» Satellite-Based Offshore Wind Resource Assessment in the Mediterranean Sea
Abstract:
Identification of prominent sea areas for the efficient exploitation of offshore wind energy potential requires primarily the assessment and modeling of several aspects of the long-term wind climate. In this work, the offshore wind speed and wind direction climate of the Mediterranean Sea is analytically described, the corresponding offshore wind energy potential is estimated on an annual and seasonal basis, and candidate areas for potential offshore wind farm development are identified. The analysis is based on ocean surface wind fields obtained from the Blended Sea Winds product, provided by the U.S. National Oceanic and Atmospheric Administration (NOAA), from 1995 to 2014. The satellite data are evaluated with reference to buoy wind measurements in the Spanish and Greek Seas. Wind data analysis reveals areas in the western and eastern Mediterranean Sea with high mean annual wind speed combined with rather low temporal variability. The obtained results suggest that offshore wind power potential in the Mediterranean Sea is fairly exploitable at specific suitable locations, such as the Gulf of Lions (with mean annual wind power density up to 1600 W/m) and the Aegean Sea (with mean annual wind power density up to 1150 W/m), that are certainly worth further in-depth assessment for exploiting offshore wind energy. Finally, based on the available offshore wind resource potential and the water depth suitability, three specific sites (in the Gulf of Valencia and the Adriatic and Ionian Seas) are selected and the average wind power output for a specific wind turbine type is estimated.
Autors: Takvor Soukissian;Flora Karathanasi;Panagiotis Axaopoulos;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jan 2017, volume: 42, issue:1, pages: 73 - 86
Publisher: IEEE
 
» Saturation Behavior for a Comb-Like Light-Induced Synaptic Transistor
Abstract:
We propose and fabricate a comb-like light-induced synaptic transistor composed of two InGaN/GaN multiple-quantum-well diodes (MQWDs) with a common base. One InGaN/GaN MQWD is used as an emitter of light, and another InGaN/GaN MQWD is used as a collector. When a presynaptic voltage is applied to the emitter to generate light, the collector absorbs the emitted light and demonstrates an excitatory postsynaptic voltage (EPSV). Saturated EPSV behavior occurs at the collector when multiple pulse signals are continuously applied to the emitter. The saturated EPSV value is increased and the saturated pulse number is reduced as the amplitude of the applied pulse signal increases. Experimental results indicate that continuous stimuli with a high pulse intensity will greatly improve the memory effect during the learning process.
Autors: Guixia Zhu;Xumin Gao;Yuanhang Li;Jialei Yuan;Wei Yuan;Yongchao Yang;Zhiyu Zhang;Yongjin Wang;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 71 - 74
Publisher: IEEE
 
» Scalable Approach for Power Droop Reduction During Scan-Based Logic BIST
Abstract:
The generation of significant power droop (PD) during at-speed test performed by Logic Built-In Self Test (LBIST) is a serious concern for modern ICs. In fact, the PD originated during test may delay signal transitions of the circuit under test (CUT): an effect that may be erroneously recognized as delay faults, with consequent erroneous generation of test fails and increase in yield loss. In this paper, we propose a novel scalable approach to reduce the PD during at-speed test of sequential circuits with scan-based LBIST using the launch-on-capture scheme. This is achieved by reducing the activity factor of the CUT, by proper modification of the test vectors generated by the LBIST of sequential ICs. Our scalable solution allows us to reduce PD to a value similar to that occurring during the CUT in field operation, without increasing the number of test vectors required to achieve a target fault coverage (FC). We present a hardware implementation of our approach that requires limited area overhead. Finally, we show that, compared with recent alternative solutions providing a similar PD reduction, our approach enables a significant reduction of the number of test vectors (by more than 50%), thus the test time, to achieve a target FC.
Autors: Martin Omaña;Daniele Rossi;Filippo Fuzzi;Cecilia Metra;Chandrasekharan Chandra Tirumurti;Rajesh Galivanche;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 238 - 246
Publisher: IEEE
 
» Scalable GaSb/InAs Tunnel FETs With Nonuniform Body Thickness
Abstract:
GaSb/InAs heterojunction tunnel FETs are strong candidates in building future low-power ICs, as they could provide both steep subthreshold swing and large ON-state current (). However, at short-channel lengths, they suffer from large tunneling leakage originating from the small bandgap and small effective masses of the InAs channel. As proposed in this paper, this problem can be significantly mitigated by reducing the channel thickness, meanwhile retaining a thick source-channel tunnel junction, thus forming a design with a nonuniform body thickness. Because of the quantum confinement, the thin InAs channel offers a large bandgap and large effective masses, reducing the ambipolar and source-to-drain tunneling leakage at OFF-state. The thick GaSb/InAs tunnel junction, instead, offers a low tunnel barrier and small effective masses, allowing a large tunnel probability at ON-state. In addition, the confinement-induced band discontinuity enhances the tunnel electric field and creates a resonant state, further improving . Atomistic quantum transport simulations show that ballistic A/m is obtained at 15-nm channel length, A/m, and V, while with uniform body thickness, the largest achievable is only 25 A/m. Simulations also indicate that this design is scalable to sub-10-nm channel length.
Autors: Jun Z. Huang;Pengyu Long;Michael Povolotskyi;Gerhard Klimeck;Mark J. W. Rodwell;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 96 - 101
Publisher: IEEE
 
» Scanning the Issue
Abstract:
Looking at Intersections: A Survey of Intersection Monitoring, Behavior and Safety Analysis of Recent Studies
Autors: Petros Ioannou;A. V. ‘Bal’ Balakrishnan;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Jan 2017, volume: 18, issue:1, pages: 1 - 3
Publisher: IEEE
 
» Scavenging for Energy: A Rectenna Design for Wireless Energy Harvesting in UHF Mobile Telephony Bands
Abstract:
The development of distributed and ubiquitous electronic devices is an achievement of modern technology that has the potential to revolutionize many aspects of human life. Such electronic devices are being employed not only in consumer areas like home automation, intelligent transportation systems, and personal entertainment but also for health-care applications, such as noninvasive biomedical parameter monitoring, as well as industrial and military applications.
Autors: Valentina Palazzi;Massimo Del Prete;Marco Fantuzzi;
Appeared in: IEEE Microwave Magazine
Publication date: Jan 2017, volume: 18, issue:1, pages: 91 - 99
Publisher: IEEE
 
» Secure Degrees of Freedom of the Gaussian Diamond-Wiretap Channel
Abstract:
In this paper, we consider the Gaussian diamond-wiretap channel that consists of an orthogonal broadcast channel from a source to two relays and a Gaussian fast-fading multiple access-wiretap channel from the two relays to a legitimate destination and an eavesdropper. For the multiple access part, we consider both the case with full channel state information (CSI) and the case with no eavesdropper’s CSI, at the relays and the legitimate destination. For both the cases, we establish the exact secure degrees of freedom and generalize the results for multiple relays. Our results show: 1) how to strike a balance between sending message symbols and common noise symbols from the source to the relays in the broadcast component and 2) how to combine artificial noise-beamforming and noise-alignment techniques at the relays in the multiple access component. In the case with full CSI, we propose a scheme where the relays simultaneously beamform common noise signals in the null space of the legitimate destination’s channel, and align them with the message signals at the eavesdropper. In the case with no eavesdropper’s CSI, we present a scheme that efficiently utilizes the broadcast links by incorporating computation between the message and common noise symbols at the source. Finally, most of our achievability and converse techniques can also be adapted to the Gaussian (non-fading) channel model.
Autors: Si-Hyeon Lee;Wanyao Zhao;Ashish Khisti;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 496 - 508
Publisher: IEEE
 
» Security of an Ordered-Based Distributive Jamming Scheme
Abstract:
This letter proposes a new efficient yet simple distributed ordered-based jamming scheme for securing a legitimate transmission and powering a wireless receiver equipped with a nonlinear energy harvester. A legitimate source node (Alice) communicates with one legitimate receive node (Bob) and one legitimate radio-frequency energy-harvesting node (Dana) in the presence of an eavesdropping node (Eve). A set of cooperative nodes (Jims) are deployed in the network to power Dana and secure the legitimate transmissions by jamming Eve. In each time slot, only one Jim is selected. Our proposed scheme does not require the instantaneous channel state information (CSI) of Eve’s links or the global CSI of the legitimate nodes at a legitimate central unit. The numerical results demonstrate that our scheme achieves higher average secrecy throughput than that achieved by the best-jammer scheme.
Autors: Ahmed El Shafie;Dusit Niyato;Naofal Al-Dhahir;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 72 - 75
Publisher: IEEE
 
» Segmented Kalman Filter Based Antistrong Transient Impact Method for Vortex Flowmeter
Abstract:
Vortex flowmeter is installed in piping to measure the fluid flow rate. The piping is easily disturbed by strong transient impact in the application fields, such as other components impacting on the pipeline, manual knocking on the pipe, and opening and closing of valves. The strong transient impact will be picked up by the vortex flow sensor, which makes the vortex flowmeter output wrong measurement results. The current commonly used digital signal processing method can do nothing about it. To solve this problem, an experimental setup is built in our laboratory to study the impact interference, and a large number of vortex flow sensor output signals are collected. The characteristics of transient impacts outputted by the vortex sensor are analyzed so as to describe this type of signal quantitatively. The pattern of transient impact is that the signal amplitudes increase suddenly and then attenuate gradually. A segmented Kalman filter based digital signal processing method is proposed according to this pattern. The data segment containing strong transient impact is found first; the transient impact power is reduced by filtering the data segment second; and through spectral analysis of the filtered signal, the maximum peak of the spectrum is extracted as the vortex flow signal finally. The algorithm is implemented in real time by a low-power microcontroller. Both gas and water flow experiments have been conducted to verify the validity and reliability of the antistrong transient impact algorithm.
Autors: Chun-Li Shao;Ke-Jun Xu;Zhang-Ping Shu;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Jan 2017, volume: 66, issue:1, pages: 93 - 103
Publisher: IEEE
 
» Seismic Time–Frequency Analysis via STFT-Based Concentration of Frequency and Time
Abstract:
Time–frequency (TF) analysis can reveal local variations in seismic data processing and interpretation, where seismic signals are nonstationary and time varying. High-quality TF representation (TFR) is important for revealing the local information about these nonstationary seismic signals and describing geological structures. Due to the Heisenberg uncertainty principle, traditional TF methods (e.g., short time Fourier transform and continuous wavelet transform) cannot get the finest time resolution and the best frequency resolution at the same time, which leads to ambiguous TFR with a negative effect on the seismic signal analysis. Concentration in frequency and time is proposed to distinguish the different TF contents of time-dependent signals with time-varying amplitude and instantaneous frequencies. We introduce this promising TF analysis tool to seismic data processing. Experiments on synthetic signals and seismic data show its validity and effectiveness, which is helpful for seismic data interpretation in the future.
Autors: Naihao Liu;Jinghuai Gao;Xiudi Jiang;Zhuosheng Zhang;Qian Wang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 127 - 131
Publisher: IEEE
 
» Seizure Prediction Using Undulated Global and Local Features
Abstract:
In this study, a seizure prediction method is proposed based on a patient-specific approach by extracting undulated global and local features of preictal/ictal and interictal periods of EEG signals. The proposed method consists of feature extraction, classification, and regularization. The undulated global feature is extracted using phase correlation between two consecutive epochs of EEG signals and an undulated local feature is extracted using the fluctuation and deviation of EEG signals within the epoch. These features are further used for classification of preictal/ictal and interictal EEG signals. A regularization technique is applied on the classified outputs for the reduction of false alarms and improvement of the overall prediction accuracy (PA). The experimental results confirm that the proposed method provides high PA (i.e., 95.4%) with low false positive per hour using intracranial EEG signals in different brain locations of 21 patients from a benchmark dataset. Combining global and local features enables the transition point to be determined between different types of signals with greater accuracy, resulting successful versus unsuccessful prediction of seizure. The theoretical contribution of this study may provide an opportunity for the development of a clinical device to predict forthcoming seizure in real time.
Autors: Mohammad Zavid Parvez;Manoranjan Paul;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jan 2017, volume: 64, issue:1, pages: 208 - 217
Publisher: IEEE
 
» Selective Assembly System With Unreliable Bernoulli Machines and Finite Buffers
Abstract:
Selective assembly has been employed to obtain high-precision assemblies of two mating parts. Most studies only consider the case where machines are reliable and the buffer capacity is infinite. However, unreliable machines and finite buffers are commonly observed in many assembly systems, such as battery pack assemblies and powertrain production lines in the automotive industry. This paper studies a selective assembly system with two component machines, two finite buffers, and one assembly machine. Each component can exhibit different quality behaviors. Bernoulli machine reliability models are assumed. Analytical methods based on a two-level decomposition procedure are developed to evaluate the system performance efficiently. Numerical experiments suggest that the iteration always converges and can deliver high estimation accuracy. Extension to larger systems is also discussed.
Autors: Feng Ju;Jingshan Li;Weiwen Deng;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jan 2017, volume: 14, issue:1, pages: 171 - 184
Publisher: IEEE
 
» Self-Heating During submicrosecond Current Transients in Pr0.7Ca0.3MnO3-Based RRAM
Abstract:
In filamentary RRAM, the role of self-heating in set/reset (by ion transport) is well established. However, in nonfilamentary Pr0.7Ca0.3MnO3 (PCMO) RRAM, self-heating during set/reset has not been explored. Recently, we have shown self-heating to explain nonlinearity in dc IV characteristics. In this paper, we present the observation of self-heating using transient current during pulses. We show that the cooling timescale is limited by measurement system timescale (~30 ns). The self-heating-based experimental current transient timescale is longer (50–100 ns) and is not described by simple exponential decay. To explain this behavior, self-heating in PCMO RRAM (where Joule heating and current increase create a positive feedback) is implemented into technology computer aided design simulations. Simulations produce excellent agreement with experiments. Eventually, simulations deviate from experiments when thermally assisted ionic transport during set/reset is not included in the model. To interrupt the continuous self-heating, an n-pulse-train with cooling time between pulses versus single pulse-based set/reset experiment was designed with the same peak bias time. Set/reset effectiveness degrades as n increases while effect of increasing cooling time confirmed a cooling timescale of ~30 ns. Overall, self-heating provides a consistent explanation of the transient currents. Thus, this paper establishes that self-heating considerations must be included for PCMO-based RRAM modeling and design.
Autors: N. Panwar;A. Khanna;P. Kumbhare;I. Chakraborty;U. Ganguly;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 137 - 144
Publisher: IEEE
 
» Self-Learning RF Receiver Systems: Process Aware Real-Time Adaptation to Channel Conditions for Low Power Operation
Abstract:
Prior research has established that dynamically trading-off the performance of the radio-frequency (RF) front-end for reduced power consumption across changing channel conditions, using a feedback control system that modulates circuit and algorithmic level “tuning knobs” in real-time based on received signal quality, leads to significant power savings. It is also known that the optimal power control strategy depends on the process conditions corresponding to the RF devices concerned. This leads to an explosion in the search space needed to find the best feedback control strategy, across all combinations of channel conditions and receiver process corners, making simulation driven optimal control law design impractical and computationally infeasible. Since this problem is largely intractable due to the above complexity of simulation, we propose a self-learning strategy for adaptive RF systems. In this approach, RF devices learn their own performance vs. power consumption vs. tuning knob relationships “on-the-fly” and formulate the most power-optimal control strategy for real-time adaptation of the RF system using neural-network based learning techniques during real-time operation. The methodology is demonstrated using SISO and MIMO RF receiver front-ends as test vehicles and is supported by hardware validation leading to 2.5X-3X power savings with minimal overhead.
Autors: Debashis Banerjee;Barry Muldrey;Xian Wang;Shreyas Sen;Abhijit Chatterjee;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jan 2017, volume: 64, issue:1, pages: 195 - 207
Publisher: IEEE
 
» Self-Powered UV-B Photodetector Based on Hybrid Al:MgZnO/PEDOT:PSS Schottky Diode
Abstract:
Wide bandgap Al-doped MgZnO (AMZO) films with a Mg content up to 47.5% were prepared on sapphire substrates. Conductivities of the AMZO films were greatly improved through zinc vapor annealing. Vertical structure photodiodes were fabricated by introducing poly (3, 4-ethylenedioxythiophene) poly (styrenesulfonate) (PEDOT:PSS) as a Schottky contact. The photodiode showed characteristics response to the UV-B light, with a peak responsivity of 19.1 mA/W at 278 nm and a visible rejection ratio of over two orders without external bias. The high performance was attributed to the high conductivity of the AMZO film and good Schottky contact formed using PEDOT:PSS.
Autors: Qinghong Zheng;Jin Huang;Chuxia Han;Yanqin Chen;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 79 - 82
Publisher: IEEE
 
» Self-Triggered Model Predictive Control for Nonlinear Input-Affine Dynamical Systems via Adaptive Control Samples Selection
Abstract:
In this paper, we propose a self-triggered formulation of model predictive control for continuous-time nonlinear input-affine networked control systems. Our control method specifies not only when to execute control tasks but also provides a way to discretize the optimal control trajectory into several control samples, so that the reduction of communication load will be obtained. Stability analysis under the sample-and-hold implementation is also given, which guarantees that the state converges to a terminal region where the system can be stabilized by a local state feedback controller. Some simulation examples validate our proposed framework.
Autors: Kazumune Hashimoto;Shuichi Adachi;Dimos V. Dimarogonas;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 177 - 189
Publisher: IEEE
 
» Semantics-Enabled Framework for Spatial Image Information Mining of Linked Earth Observation Data
Abstract:
Recent developments in sensor technology are contributing toward the tremendous growth of remote sensing (RS) archives (currently, at the petabyte scale). However, this data largely remain unexploited due to the current limitations in the data discovery, querying, and retrieval capabilities. This issue becomes exacerbated in disaster situations, where there is a need for rapid processing and retrieval of the affected areas. Furthermore, the retrieval of images based on the spatial configurations of affected regions [land use/cover (LULC) classes] in an image is important in disaster situations such as floods and earthquakes. The majority of existing Earth observation (EO) image information mining (IIM) systems does not consider the spatial relations among image regions during image retrieval (aka spatial semantic gap). In this work, we have specifically addressed two issues, i.e., explicit modeling of topological and directional relationships between image regions, and development of a resource description framework (RDF)-based spatial semantic graphs (SSGs). This enables more intuitive querying and reasoning on the archived data. A spatial IIM (SIIM) framework is proposed, which integrates a logic-based reasoning mechanism to extract the hidden spatial relationships (both topological and directional) and enables image retrieval based on spatial relationships. The system is tested using several spatial relations-based queries on the RS image repository of flood-affected areas to check its applicability in post flood scenario. Precision, recall, and F-measure metrics were used to evaluate the performance of the SIIM system, which showed good potential for spatial relations-based image retrieval.
Autors: Kuldeep R. Kurte;Surya S. Durbha;Roger L. King;Nicolas H. Younan;Rangaraju Vatsavai;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 29 - 44
Publisher: IEEE
 
» Semi-Analytical Approach for Finite-Element Analysis of Multi-Turn Coil Considering Skin and Proximity Effects
Abstract:
Native application of finite-element method (FEM) to the analysis of skin and proximity effects in multi-turn coils results in large equation systems, whose solution needs long computational time. This paper proposes a semi-analytical approach to overcome this problem. For the analysis of the proximity effect, the complex permeability of a round conducting wire immersed in uniform time-harmonic magnetic fields is represented in a closed form. Then, the homogenized complex permeability over the cross section of the multi-turn coil is analytically evaluated using the Ollendorff formula. The magnetoquasistatic problem is thus replaced by the magnetostatic one, in which the multi-turn coil is treated as a uniform material with the homogenized complex permeability. The skin effect is taken into consideration by introducing the corresponding impedance in the circuit equation. The proposed method is shown to give the impedance of multi-turn coils, which is in good agreement with that obtained by the conventional FEM as well as experiments.
Autors: Hajime Igarashi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 7
Publisher: IEEE
 
» Semi-Automated Tracking: A Balanced Approach for Self-Monitoring Applications
Abstract:
The authors present an approach for designing self-monitoring technology called "semi-automated tracking," which combines both manual and automated data collection methods. Through this approach, they aim to lower the capture burdens, collect data that is typically hard to track automatically, and promote awareness to help people achieve their self-monitoring goals. They first specify three design considerations for semi-automated tracking: data capture feasibility, the purpose of self-monitoring, and the motivation level. They then provide examples of semi-automated tracking applications in the domains of sleep, mood, and food tracking to demonstrate strategies they developed to find the right balance between manual tracking and automated tracking, combining each of their benefits while minimizing their associated limitations.
Autors: Eun Kyoung Choe;Saeed Abdullah;Mashfiqui Rabbi;Edison Thomaz;Daniel A. Epstein;Felicia Cordeiro;Matthew Kay;Gregory D. Abowd;Tanzeem Choudhury;James Fogarty;Bongshin Lee;Mark Matthews;Julie A. Kientz;
Appeared in: IEEE Pervasive Computing
Publication date: Jan 2017, volume: 16, issue:1, pages: 74 - 84
Publisher: IEEE
 
» Semi-Supervised Tensor-Based Graph Embedding Learning and Its Application to Visual Discriminant Tracking
Abstract:
An appearance model adaptable to changes in object appearance is critical in visual object tracking. In this paper, we treat an image patch as a two-order tensor which preserves the original image structure. We design two graphs for characterizing the intrinsic local geometrical structure of the tensor samples of the object and the background. Graph embedding is used to reduce the dimensions of the tensors while preserving the structure of the graphs. Then, a discriminant embedding space is constructed. We prove two propositions for finding the transformation matrices which are used to map the original tensor samples to the tensor-based graph embedding space. In order to encode more discriminant information in the embedding space, we propose a transfer-learning- based semi-supervised strategy to iteratively adjust the embedding space into which discriminative information obtained from earlier times is transferred. We apply the proposed semi-supervised tensor-based graph embedding learning algorithm to visual tracking. The new tracking algorithm captures an object's appearance characteristics during tracking and uses a particle filter to estimate the optimal object state. Experimental results on the CVPR 2013 benchmark dataset demonstrate the effectiveness of the proposed tracking algorithm.
Autors: Weiming Hu;Jin Gao;Junliang Xing;Chao Zhang;Stephen Maybank;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jan 2017, volume: 39, issue:1, pages: 172 - 188
Publisher: IEEE
 
» Semiautomatic Registration of Terrestrial Laser Scanning Data Using Perspective Intensity Images
Abstract:
Point cloud registration is an important procedure for terrestrial laser scanning data processing. Artificial targets are usually used in practice to guarantee a robust registration. However, installing and locating targets are labor-intensive for large surveying and mapping project. A methodology for semiautomatic registration of terrestrial point clouds using perspective intensity images is presented in this letter. To register two point clouds, perspective intensity image series of the scanning area are first generated from the point clouds. Then, corner points are extracted from the generated perspective intensity images and are interactively selected as tie points. The 3-D coordinates of the selected tie points are directly obtained or estimated using least squares method. Registration parameters are solved using singular value decomposition. To improve robustness and accuracy of the registration, random sample consensus is used to remove outliers in the tie points. The robustness and effectiveness of the presented methodology is demonstrated by experimental results.
Autors: Yu-Bin Liang;Yan Qiu;Tie-Jun Cui;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jan 2017, volume: 14, issue:1, pages: 28 - 32
Publisher: IEEE
 
» Semidefinite Relaxation of Optimal Power Flow for AC–DC Grids
Abstract:
The proliferation of technologies operating on dc power has motivated the system planners toward integration of dc and ac grids. The optimal power flow (OPF) analysis is widely used to determine the economically efficient operating points of the power grids. The OPF problem in ac–dc grids is a non-convex optimization problem due to the nonlinear power flow equations and the operating constraints imposed by the ac–dc converters. In this paper, we study the OPF problem in ac–dc grids to address the non-convexity of the problem. The objective of the ac–dc OPF problem is to jointly minimize the generation cost and the losses on the lines and converters. The optimization problem is subject to the ac and dc power flow constraints, the limits of the voltages and line flows, and the operating limits of the converters. We use convex relaxation techniques and transform the problem to a semidefinite program. We derive a sufficient condition for zero relaxation gap to obtain the global optimal solution. Simulations are performed on an IEEE 118-bus test system connected to sample dc grids. We show that the zero relaxation gap condition holds for the case study and the global optimal solution can be obtained.
Autors: Shahab Bahrami;Francis Therrien;Vincent W.S. Wong;Juri Jatskevich;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 289 - 304
Publisher: IEEE
 
» Semiparametric Estimation of Mutual Information and Related Criteria: Optimal Test of Independence
Abstract:
We derive independence tests by means of dependence measures thresholding in a semiparametric context. Precisely, the estimates of -mutual informations, associated to -divergences between a joint distribution and the product distribution of its marginals, are derived through the dual representation of -divergences. The asymptotic properties of the proposed estimates are established, including consistency, asymptotic distributions, and large deviations principle. The obtained tests of independence are compared via their relative asymptotic Bahadur efficiency and numerical simulations. It follows that the proposed semiparametric mutual information test is the optimal one. On the other hand, the proposed approach provides a new method for estimating the mutual information in a semiparametric setting, as well as a model selection procedure in a large class of dependence models, including semiparametric copulas.
Autors: Amor Keziou;Philippe Regnault;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 57 - 71
Publisher: IEEE
 
» Semitransparent and Flexible Mechanically Reconfigurable Electrically Small Antennas Based on Tortuous Metallic Micromesh
Abstract:
A novel optically transparent, flexible, and mechanically reconfigurable zeroth-order resonant (ZOR) antenna using stretchable micromesh structure is presented in this paper. The size reduction of the antenna is achieved by using the ZOR property, and the uniform metallic patches of the antenna are replaced with the tortuous micromesh. The tortuous micromesh structures provide a high degree of freedom for stretching when encapsulated in elastomeric polymers with added feature of semitransparency. Accordingly, the structure can undergo mechanical deformation such as stretching (up to 40%), folding, or twisting without breakage. The resonant frequency of the antennas is linearly reconfigurable from 2.94 to 2.46 GHz upon stretching.
Autors: Taehee Jang;Cheng Zhang;Hongseok Youn;Jing Zhou;L. Jay Guo;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 150 - 158
Publisher: IEEE
 
» Sending Perishable Information: Coding Improves Delay-Constrained Throughput Even for Single Unicast
Abstract:
This paper considers network communications under a hard timeliness constraint, where a source node streams perishable information to a destination node over a directed acyclic graph subject to a hard delay constraint. Transmission along any edge incurs unit delay, and it is required that every information bit generated at the source at the beginning of time to be received and recovered by the destination at the end of time , where is the maximum allowed end-to-end delay. We study the corresponding delay-constrained unicast capacity problem. This paper presents the first example showing that network coding (NC) can achieve strictly higher delay-constrained throughput than routing even for the single unicast setting and the NC gain can be arbitrarily close to 2 in some instances. This is in sharp contrast to the delay-unconstrained () single-unicast case where the classic min-cut/max-flow theorem implies that coding cannot improve throughput over routing. Motivated by the above findings, a series of investigation on the delay-constrained capacity problem is also made, including: 1) an equivalent multiple-unicast representation based on a time-expanded graph approach; 2) a new delay-constrained capacity upper bound and its connections to the existing routing-based results [Ying et al. 2011]; 3) an example showing that the penalty of using random linear NC can be unbounded; and 4) a counter example of the tree-packing Edmonds’ theorem in the new delay-constrai ed setting. Built upon the time-expanded graph approach, we also discuss how our results can be readily extended to cyclic networks. Overall, our results suggest that delay-constrained communication is fundamentally different from the well-understood delay-unconstrained one and call for investigation participation.
Autors: Chih-Chun Wang;Minghua Chen;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jan 2017, volume: 63, issue:1, pages: 252 - 279
Publisher: IEEE
 
» Series–Parallel-Form Switch-Linear Hybrid Envelope-Tracking Power Supply to Achieve High Efficiency
Abstract:
Envelope tracking (ET) techniques have been used to improve the efficiency of power amplifiers in wireless communication systems. The switch-linear hybrid (SLH) ET power supply, which features both wide tracking bandwidth and high efficiency, has received a great deal of attention. In both series- and parallel-form SLH ET power supply, the power loss of the linear amplifier is relatively high. This paper proposes a series–parallel form for the SLH ET power supply, which includes two switched-mode converters and one linear amplifier, to reduce both the output voltage swing and output current of the linear amplifier, thus reducing the power loss of the linear amplifier. A current prediction control scheme is proposed to remove the current sensor in the switched-mode converter, achieving accurate control for high-frequency current. A prototype is built for 5 MHz wideband code division multiple access envelope signal tracking and 40 W peak output power. The tested efficiency of the proposed configuration is 80.4%, which is much higher than that of the series-form SLH ET power supply.
Autors: Qian Jin;Xinbo Ruan;Xiaoyong Ren;Yazhou Wang;Yang Leng;Chi K. Tse;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 244 - 252
Publisher: IEEE
 
» Series-Parallel Charge Pump Conditioning Circuits for Electrostatic Kinetic Energy Harvesting
Abstract:
This paper presents a new family of conditioning circuits used in electrostatic kinetic energy harvesters (e-KEHs), generalizing a previously reported conditioning circuit known as the Bennet's doubler. The proposed topology implements a conditioning scheme described by a rectangular charge-voltage cycle (QV-cycle) of tunable aspect ratio. These circuits show an exponential increase of the converted energy over operation time if studied in the sole electrical domain. The QV-cycle's aspect ratio can be set to values that were previously inaccessible with other exponential conditioning circuits. After a brief intuitive presentation of the new topology, its operation is rigorously analyzed and its dynamics are quantitatively derived in the electrical domain. In particular, the aspect ratio of the rectangular QV-cycle describing the biasing scheme of the transducer is expressed as a function of the circuit's parameters. Practical considerations about the use of the reported conditioning circuits in actual e-KEHs are also presented. These include a discussion on the applications of the proposed conditioning, a description of the effects of electrical nonidealities, and a proposition of an energy extracting interface.
Autors: Armine Karami;Dimitri Galayko;Philippe Basset;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Jan 2017, volume: 64, issue:1, pages: 227 - 240
Publisher: IEEE
 
» Shifting Trends in Bimodal Phytoplankton Blooms in the North Pacific and North Atlantic Oceans From Space With the Holo-Hilbert Spectral Analysis
Abstract:
Merged satellite ocean color data were used to examine trends in the timing and magnitude of phytoplankton blooms. Special emphasis was placed on the peak shift of spring and autumn/winter blooms in the North Pacific and North Atlantic Oceans with bimodal seasonal cycles. Ensemble empirical mode decomposition and Holo-Hilbert spectral analysis were combined to extract seasonal signals and investigate their modulation at multiple time-scales. In the temperate North Atlantic Ocean, earlier and decreasing spring blooms were detected with delayed and increased autumn blooms. The temperate North Pacific Ocean presented delayed and increased spring and autumn blooms, with the delay in fall blooms was larger than spring ones. The separation between two bloom peaks was increasing in both temperate North Atlantic and Pacific regions. The intrinsic variation in bloom timing and magnitude in these selected regions could be clearly extracted by ensemble empirical mode decomposition. Further Holo-Hilbert spectral results showed that changes in the annual cycle and bloom characteristics were modulated by interannual variability. These results suggest the critical role of interannual variability in the modulation of phytoplankton seasonality.
Autors: Min Zhang;Yuanling Zhang;Fangli Qiao;Jia Deng;Gang Wang;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 57 - 64
Publisher: IEEE
 
» Short Time High-Resistance State Instability of TaOx-Based RRAM Devices
Abstract:
In this letter, TiN/TaO/Ta2O5–x/Pt-based resistive switching devices were fabricated and tested. Short time high-resistance state instability phenomenon was observed during pulse programming verification measurement. This instability phenomenon was observed in about a minute after the RESET operation for high resistance states. In contrast, the measured low-resistance states after SET operation with current compliance are quite stable. This high resistance short time instability could cause incorrect write operations and reliability issues. Possible mechanisms were proposed to explain this high resistance states short time instability phenomenon of the TaOx-based resistive switching devices.
Autors: Xinyi Li;Huaqiang Wu;Bin Gao;Ning Deng;He Qian;
Appeared in: IEEE Electron Device Letters
Publication date: Jan 2017, volume: 38, issue:1, pages: 32 - 35
Publisher: IEEE
 
» Sign-Magnitude Encoding for Efficient VLSI Realization of Decimal Multiplication
Abstract:
Decimal multiplication is a complex operation, where intermediate partial products (IPPs) are commonly selected from a set of precomputed radix- multiples. Some works require only via recoding digits of to one-hot representation of signed digits in . This reduces the selection logic at the cost of one extra IPP. Two’s complement signed-digit (TCSD) encoding is often used to represent IPPs, where dynamic negation (via one xor per bit of multiples) is required for the recoded digits of in . In this paper, despite generation of 17 IPPs, for 16-digit operands, we manage to start the partial product reduction (PPR) with 16 IPPs that enhance the VLSI regularity. Moreover, we save 75% of negating xors via representing precomputed multiples by sign-magnitude signed-digit (SMSD) encoding. For the first-level PPR, we devise an efficient adder, with two SMSD input numbers, whose sum is represented with TCSD encoding. Thereafter, multilevel TCSD 2:1 reduction leads to two TCSD accumulated partial products, which collectively undergo a special early initiated conversion scheme to get at the final binary-coded decimal product. As such, a VLSI implementation of -digit parallel decimal multiplier is synthesized, wher- evaluations show some performance improvement over previous relevant designs.
Autors: Saeid Gorgin;Ghassem Jaberipur;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 75 - 86
Publisher: IEEE
 
» Signal Model-Based Fault Coding for Diagnostics and Prognostics of Analog Electronic Circuits
Abstract:
Analog circuits have been extensively used in industrial systems, and their failure may make the systems work abnormally and even cause accidents. In order to monitor their status, detect faults, and predict their failure early, this study proposes a signal model-based fault coding to monitor the circuit response after being stimulated to perform a fault diagnosis without training a large amount of sample data and fault classifiers. Manifold features extracted from circuit responses are associated with a fault-indicating curve in the feature space, in which a group of fault bases are uniformly and continuously distributed along with gradual deviation from the nominal value of one critical component. These bases can be deployed in a factory setting but used during field operation. Fault coding is converted to a novel optimization problem, and the optimized solution forms a fault code representing fault class, suitable for realizing fault detection, and isolation for different components. A fault indicator based on comparison between fault codes can describe performance degradation trends. To improve the prediction accuracy, historical degradation data are collected and considered as a priori exemplars, and a novel exemplar-based conditional particle filter is proposed to track a degradation process for the prediction of remaining useful performance. Case studies on two analog filter circuits demonstrate that the proposed method achieves relatively high fault diagnosis and prognosis accuracy. The main advantages of our study are two-fold: first, the high diagnostic accuracy can still be obtained even if there is no large amount of training data; second, the prognostic effect remains relatively stable whenever triggering prognosis module.
Autors: Zhenbao Liu;Taimin Liu;Junwei Han;Shuhui Bu;Xiaojun Tang;Michael Pecht;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 605 - 614
Publisher: IEEE
 
» Signal Processing Projects at Technische Universität Darmstadt: How to engage undergraduate students in signal processing practice
Abstract:
This article is meant to share our experience on integrating signal processing hands-on opportunities into formal engineering education at Technische Universität (TU) Darmstadt, Germany. As many universities face the challenge of how best to provide hands-on experience to undergraduate students, we hope to inspire our colleagues and perhaps trigger new hands-on projects by sharing our insights. At TU Darmstadt, we believe that it is essential to provide undergraduate students with hands-on signal processing opportunities right from the starting point of their studies through graduation.
Autors: Tim Schack;Michael Eric Muma;Abdelhak M. Zoubir;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 16 - 30
Publisher: IEEE
 
» Signal Processing: The Expected and the Unexpected [From the Editor]
Abstract:
Autors: Min Wu;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 3 - 3
Publisher: IEEE
 
» Signal-Tracing Techniques for In-System FPGA Debugging of High-Level Synthesis Circuits
Abstract:
High-level synthesis (HLS) promises to increase designer productivity in the face of increasing field-programmable gate array sizes, and broaden the market of use, allowing software designers to reap the benefits of hardware implementation. One roadblock to HLS adoption is the lack of an in-system debugging infrastructure. Although designers can run their software code on a workstation, or simulate the register-transfer level, neither can reliably capture the behaviors, and therefore bugs, that may be present in the final system. Debugging hardware circuits in-system requires using signal-tracing to record circuit behavior for later offline analysis. In this paper, we present a debugging architecture, which automatically records key hardware signals, and relates them back to the original software source code. This architecture allows designers to debug HLS circuits in-system, in the context of the original source code. We present several signal-tracing techniques, tailored to HLS circuits, which allow a much longer execution trace to be captured. These techniques include signal compression, dynamically changing which signals are recorded cycle-by-cycle, and offline signal restoration. Compared to using an embedded logic analyzer to perform signal-tracing, our architecture increases the length of execution trace that can be recorded by 127X. For each 100 Kb of trace buffer memory, our architecture can record 15 369 executed lines of C code.
Autors: Jeffrey Goeders;Steven J. E. Wilton;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jan 2017, volume: 36, issue:1, pages: 83 - 96
Publisher: IEEE
 
» Significance and detection of very low degree of polymerization of paper in transformers
Abstract:
It is a general belief that mineral oil filled power transformers are designed to operate reliably for up to 40 years. However, there are many transformers installed worldwide operating well beyond such age. Therefore, transformer end-of-life should not be simply indicated by the designed 40 years, but determined by the insulation system end-of-life.
Autors: Michel Duval;Alfonso De Pablo;Ivanka Atanasova-Hoehlein;Marius Grisaru;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Jan 2017, volume: 33, issue:1, pages: 31 - 38
Publisher: IEEE
 
» Silicon-Integrated High-Density Electrocortical Interfaces
Abstract:
Recent demand and initiatives in brain research have driven significant interest toward developing chronically implantable neural interface systems with high spatiotemporal resolution and spatial coverage extending to the whole brain. Electroencephalography-based systems are noninvasive and cost efficient in monitoring neural activity across the brain, but suffer from fundamental limitations in spatiotemporal resolution. On the other hand, neural spike and local field potential (LFP) monitoring with penetrating electrodes offer higher resolution, but are highly invasive and inadequate for long-term use in humans due to unreliability in long-term data recording and risk for infection and inflammation. Alternatively, electrocorticography (ECoG) promises a minimally invasive, chronically implantable neural interface with resolution and spatial coverage capabilities that, with future technology scaling, may meet the needs of recently proposed brain initiatives. In this paper, we discuss the challenges and state-of-the-art technologies that are enabling next-generation fully implantable high-density ECoG interfaces, including details on electrodes, data acquisition front-ends, stimulation drivers, and circuits and antennas for wireless communications and power delivery. Along with state-of-the-art implantable ECoG interface systems, we introduce a modular ECoG system concept based on a fully encapsulated neural interfacing acquisition chip (ENIAC). Multiple ENIACs can be placed across the cortical surface, enabling dense coverage over wide area with high spatiotemporal resolution. The circuit and system level details of ENIAC are presented, along with measurement results.
Autors: Sohmyung Ha;Abraham Akinin;Jiwoong Park;Chul Kim;Hui Wang;Christoph Maier;Patrick P. Mercier;Gert Cauwenberghs;
Appeared in: Proceedings of the IEEE
Publication date: Jan 2017, volume: 105, issue:1, pages: 11 - 33
Publisher: IEEE
 
» Simplified High-Order DOA and Range Estimation With Linear Antenna Array
Abstract:
In this letter, we propose a new efficient method to estimate the direction-of-arrival (DOA) and range of near-field sources in a decoupled way. First, a non-Hermitian cumulant matrix is constructed, whose eigenvectors associated with zero eigenvalues are used to directly estimate the DOA by using the MUSIC algorithm. Then, the ranges are estimated with the estimated DOA by orthogonalizing the remained eigenvectors. Compared with other modified 2-D MUSIC, the proposed algorithm can greatly reduce the computational complexity by avoiding a 2-D search with only one matrix and one eigenvalue decomposition. Simulation results show the effectiveness of the proposed method.
Autors: Jianzhong Li;Yide Wang;Cédric Le Bastard;Gang Wei;Biyun Ma;Meng Sun;Zhiwen Yu;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 76 - 79
Publisher: IEEE
 
» Simulation of Inrush Dynamics for Unbalanced Distribution Systems Using Dynamic-Phasor Models
Abstract:
Microgrids are a possible solution to mitigate the extensive interruptions in service to end-use customers caused by abnormal events, such as major natural disasters. Microgrids can be formed by energizing portions of the distribution system to interconnect generators and critical loads. In this scenario, inrush dynamic currents can present a barrier for forming microgrids by preventing the necessary switching operations and/or damaging equipment. Modeling inrush dynamics, through electromagnetic transient tools, presents a challenge when the microgrid represents a large portion of a distribution feeder. This paper uses a dynamic-phasor approach to approximate the envelope of inrush dynamics; thus, allowing simulations of large systems. The two main contributions of this paper are: a) a new formulation to solve a set of dynamic-phasor differential equations representing an unbalanced distribution system; and b) modeling of transformer saturation in the dynamic-phasor frame. These two contributions allow the inrush phenomena to be simulated on full-size microgrid and/or distribution feeder models. The new formulation and model are implemented in GridLAB-D, and tested on IEEE test systems. The simulations showed good approximation as compared with a more accurate electromagnetic transient simulation in PSCAD software.
Autors: Marcelo A. Elizondo;Francis K. Tuffner;Kevin P. Schneider;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jan 2017, volume: 32, issue:1, pages: 633 - 642
Publisher: IEEE
 
» Simulations of Sectioned Cavity for High-Harmonic Gyrotron
Abstract:
A recently proposed method of decreasing the ohmic losses in long gyrotron cavities is thoroughly studied. Its workability is proved using various simulations. A fourth-cyclotron-harmonic submillimeter-wavelength gyrotron, which utilizes this method, is designed, and its ability to operate with high efficiency is numerically demonstrated.
Autors: Ilya V. Bandurkin;Yury K. Kalynov;Petr B. Makhalov;Ivan V. Osharin;Andrey V. Savilov;Ilya V. Zheleznov;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 300 - 305
Publisher: IEEE
 
» Simulations to True Animals’ Long-Distance Geomagnetic Navigation
Abstract:
How animals navigate in their cross-continental migration has puzzled scientists for centuries. To date, the mechanism behind this mysterious navigation remains unclear. In this paper, a hypothesis is developed and computer simulations have been performed to investigate long-distance animal navigation. Simulation results show that animals may be able to complete their long-distance navigation by observing a spatial angle included by the geomagnetic field line and a geographic direction, without necessarily knowing any prior landmark information. Our results not only match existing observation reports in detail on the long-distance migration routes of animals, but also are able to explain the conflicting evidence on the role of geomagnetic field in animal navigation. We think our results could help reveal the actual mechanism of animal navigation. This paper also provides a potential solution for global and local area navigation of mankind and machines assisted by artificial sensors.
Autors: Xiaokang Qi;Dexin Ye;Yongzhi Sun;Changzhi Li;Lixin Ran;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 8
Publisher: IEEE
 
» Simultaneous Analysis of 2D Echo Views for Left Atrial Segmentation and Disease Detection
Abstract:
We propose a joint information approach for automatic analysis of 2D echocardiography (echo) data. The approach combines a priori images, their segmentations and patient diagnostic information within a unified framework to determine various clinical parameters, such as cardiac chamber volumes, and cardiac disease labels. The main idea behind the approach is to employ joint Independent Component Analysis of both echo image intensity information and corresponding segmentation labels to generate models that jointly describe the image and label space of echo patients on multiple apical views, instead of independently. These models are then both used for segmentation and volume estimation of cardiac chambers such as the left atrium and for detecting pathological abnormalities such as mitral regurgitation. We validate the approach on a large cohort of echoes obtained from 6,993 studies. We report performance of the proposed approach in estimation of the left-atrium volume and detection of mitral-regurgitation severity. A correlation coefficient of 0.87 was achieved for volume estimation of the left atrium when compared to the clinical report. Moreover, we classified patients that suffer from moderate or severe mitral regurgitation with an average accuracy of 82%.
Autors: Gregory Allan;Saman Nouranian;Teresa Tsang;Alexander Seitel;Maryam Mirian;John Jue;Dale Hawley;Sarah Fleming;Ken Gin;Jody Swift;Robert Rohling;Purang Abolmaesumi;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jan 2017, volume: 36, issue:1, pages: 40 - 50
Publisher: IEEE
 
» Simultaneous Guiding Template Optimization and Redundant via Insertion for Directed Self-Assembly
Abstract:
In sub-10 nm technology nodes, next generation lithography technologies are urgently required, and the diblock copolymer directed self-assembly (DSA) technology has shown its strong potential for contact/via layer fabrication. In addition, post-layout redundant via insertion has become a necessary step to guarantee sufficient yield and circuit reliability. However, existing redundant via insertion algorithms are not suitable for DSA since they could seriously deteriorate via manufacturability. In contrast, a sophisticated DSA-aware redundant via insertion algorithm may not only enhance circuit reliability but also improve DSA manufacturability. In this paper, we propose the first work of simultaneous guiding template optimization and redundant via insertion for DSA. Two integer linear programming (ILP)-based algorithms and an efficient graph-based approach are provided. The two ILP-based algorithms optimally maximize via manufacturability and the redundant via insertion rate. In addition, reduction techniques are presented to greatly improve the computational efficiency of ILP. For the graph-based approach, all feasible via patterns composed of original vias and redundant vias are identified. Then, the original problem is transformed into a graph formulation and efficiently optimized. Experimental results show that the ILP-based algorithms can find optimal solutions with reasonable computation time, and the graph-based algorithm can solve the problem much more efficiently and derive near-optimal solutions.
Autors: Shao-Yun Fang;Yun-Xiang Hong;Yi-Zhen Lu;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jan 2017, volume: 36, issue:1, pages: 156 - 169
Publisher: IEEE
 
» Simultaneous Wireless Power/Data Transfer for Electric Vehicle Charging
Abstract:
The major drawback of the battery charging in traditional electric vehicles is the use of plug-in charging devices. The aim of this paper is to propose a wireless battery charging method, in addition to power transfer, data related to battery status, vehicle ID code, or emergency messages can be simultaneously transferred between the grid and vehicle. This work applies inductive power transfer to complete the charging system. The proposed control system can monitor the operating status on the secondary (vehicle) side in real time and adjust charging current depending on the battery status. Furthermore, the proposed mechanism is able to make an immediate stop, if there is any contingency, such as overcharging voltage or current. This will be beneficial to efficient and safety concern during the charging process.
Autors: Chih-Cheng Huang;Chun-Liang Lin;Yuan-Kang Wu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 682 - 690
Publisher: IEEE
 
» Single Image Super-Resolution via Locally Regularized Anchored Neighborhood Regression and Nonlocal Means
Abstract:
The goal of learning-based image super resolution (SR) is to generate a plausible and visually pleasing high-resolution (HR) image from a given low-resolution (LR) input. The SR problem is severely underconstrained, and it has to rely on examples or some strong image priors to reconstruct the missing HR image details. This paper addresses the problem of learning the mapping functions (i.e., projection matrices) between the LR and HR images based on a dictionary of LR and HR examples. Encouraged by recent developments in image prior modeling, where the state-of-the-art algorithms are formed with nonlocal self-similarity and local geometry priors, we seek an SR algorithm of similar nature that will incorporate these two priors into the learning from LR space to HR space. The nonlocal self-similarity prior takes advantage of the redundancy of similar patches in natural images, while the local geometry prior of the data space can be used to regularize the modeling of the nonlinear relationship between LR and HR spaces. Based on the above two considerations, we first apply the local geometry prior to regularize the patch representation, and then utilize the nonlocal means filter to improve the super-resolved outcome. Experimental results verify the effectiveness of the proposed algorithm compared with the state-of-the-art SR methods.
Autors: Junjun Jiang;Xiang Ma;Chen Chen;Tao Lu;Zhongyuan Wang;Jiayi Ma;
Appeared in: IEEE Transactions on Multimedia
Publication date: Jan 2017, volume: 19, issue:1, pages: 15 - 26
Publisher: IEEE
 
» Size Dependence of Nanoparticle Magnetization
Abstract:
The magnetization of noninteracting metallic nanoparticles is investigated by comparing the particle-size and temperature dependences of the magnetization for several mechanisms. The nanoparticle magnetization deviates from that of the underlying bulk materials due to zero-temperature and thermal effects, and on a mean-field level, the corresponding surface-core interaction is described by a Landau–Ginzburg approach. A major factor is the reduced atomic coordination at the surface, which has often, but not always, opposite effects on the zero-temperature magnetization and Curie temperatures. The coordination effect is particularly pronounced for very weak itinerant ferromagnets and for strongly exchange-enhanced Pauli paramagnets. With regard to external magnetic fields, the nanoparticle magnetization involves several “superparamagnetic” phenomena, namely, Néel relaxation, Brownian relaxation, and Langevin macrospin paramagnetism.
Autors: R. Skomski;B. Balamurugan;P. Manchanda;M. Chipara;D. J. Sellmyer;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 7
Publisher: IEEE
 
» Skyrmion Sensor-Based Low-Power Global Interconnects
Abstract:
In this paper, we propose the use of magnetic skyrmion sensors for low-voltage, low-current global interconnects. Magnetic skyrmions have shown great potential for low-power circuit applications, since skyrmions can be generated and moved by remarkably low-current pulses. We propose the use of skyrmion-based current sensors at the receiver that allows low-current signal transmission through the line. The proposed skyrmion sensor consists of a magnetic nanotrack on top of a spin-Hall metal (SHM). The skyrmion is nucleated in the nanotrack by using spin-polarized current and, subsequently, moved along the nanotrack by using a charge current through the SHM. This charge current is the input current from a global interconnect line, which moves the skyrmion depending on the logic input to the line. The resistance of a magnetic tunnel junction (MTJ) at the receiver is based on the movement/location of the skyrmion. This resistance change is sensed using a reference MTJ and a simple complementary metal–oxide–semiconductor (CMOS) inverter. Such a receiver configuration acts as a built-in latch, and hence, expensive voltage converters or transimpedance amplifiers can be avoided, which are the bottlenecks in a conventional low-power interconnect design. Our simulation results indicate that for a 10 mm Cu-line in 45 nm CMOS technology, the energy consumption with skyrmion-based sensing is lower compared with full swing and lower compared with low-swing CMOS interconnect.
Autors: Zubair Al Azim;Mei-Chin Chen;Kaushik Roy;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jan 2017, volume: 53, issue:1, pages: 1 - 6
Publisher: IEEE
 
» Sliding-Mode Control of Memristive Chua's Systems via the Event-Based Method
Abstract:
This brief studies the sliding-mode control (SMC) scheme of uncertain memristive Chua's circuits via the event-based method. The sliding-mode controller possesses the advantage of its strong robustness and fast response over other control techniques. However, this controller is generally required to be executed in a continuous manner in order to make the trajectories of augmented systems drive onto the sliding surface in a finite time. In practice, these control methods are performed in a digital form. Thus, this brief proposes the event-based SMC which is executed only when necessary. Meanwhile, the existence of the lower bound for interexecution time is derived in this brief. Finally, a case study is conducted to illustrate the effectiveness of the derived results.
Autors: Shiping Wen;Tingwen Huang;Xinghuo Yu;Michael Z. Q. Chen;Zhigang Zeng;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Jan 2017, volume: 64, issue:1, pages: 81 - 85
Publisher: IEEE
 
» Small Antennas Remote Impedance Measurement Using Electrostatic Discharge
Abstract:
The conventional techniques to measure the input impedance of an antenna are based on comparing the reflected signal to the incident signal at the antenna port at a given frequency. A network analyzer connected to the antenna under test through a feeding cable is the most common impedance measurement setup. The induced current on the outer surface of the feeding cable in the electrically small antenna (ESA) case, however, significantly interferes with this process. Therefore, the traditional methods to measure the input impedance such as using a network analyzer may not be suitable for an ESA. A remote impedance measurement technique based on the impulse responses of an ESA terminated to three standard loads, short/open/matched load, is introduced. Two different types of antennas are designed and simulated using a full-wave simulator and then the impulse responses are computed using a transient simulator software. Thereafter, two different circuit models are introduced and the parameters of these models are computed using three impulse responses. The input impedance of both antennas are computed directly from the full-wave simulations as well as the remote measurement technique and the results are compared. Finally, both antennas are prototyped, measured, and the input impedances of the antennas are compared for the direct measurement using a network analyzer and the proposed technique. The presented results confirm the accuracy of the proposed method.
Autors: Majid Manteghi;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 44 - 51
Publisher: IEEE
 
» Small Data, Mid Data, and Big Data Versus Algebra, Analysis, and Topology [Perspectives]
Abstract:
Big data has become a hot topic during the last few years. But at times, its meaning has been quite confusing. I hope that through sharing my thoughts in this article, we can have a better understanding of what big data is.
Autors: Xiang-Gen Xia;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 48 - 51
Publisher: IEEE
 
» Small-Area Si Photovoltaics for Low-Flux Infrared Energy Harvesting
Abstract:
Silicon photovoltaics are prospective candidates to power mm-scale implantable devices. These applications require excellent performance for small-area cells under low-flux illumination condition, which is not commonly achieved for silicon cells due to shunt leakage and recombination losses. Small area (1–10 mm) silicon photovoltaic cells are studied in this paper, where performance improvements are demonstrated using a surface n-type doped emitter and Si3N4 passivation. A power conversion efficiency of more than 17% is achieved for 660-nW/mm2 illumination at 850 nm. The silicon cells demonstrate improved power conversion efficiency and reduced degradation under low illumination conditions in comparison with conventional crystalline silicon photovoltaic cells available commercially.
Autors: Eunseong Moon;David Blaauw;Jamie D. Phillips;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 15 - 20
Publisher: IEEE
 
» Soft Error Rate Reduction of Combinational Circuits Using Gate Sizing in the Presence of Process Variations
Abstract:
Soft errors in combinational logic circuits are emerging as a significant reliability concern for nanoscale VLSI designs. This paper presents a novel sensitivity-based gate sizing methodology to reduce the soft error rate (SER) of combinational circuits in the presence of process variations. The proposed method is based on modeling the statistics of SER of the circuit gates as a random variable to formulate a statistical optimization problem. A backward traversing algorithm with capability for incremental analysis is developed for computing the distribution of circuit gates of SER random variables. We present a gate resizing algorithm in which the gates with the most contribution to the circuit SER are selected in a candidate set using a statistical ordering approach. The proposed algorithm trades off SER reduction and area overheads. The experimental results show that using the proposed methodology, the circuit statistical SER can be reduced by up to 56.4% compared with the 14.8% SER reduction of a circuit obtained using the worst case methodology at the expense of 10% area overhead under 10% process variation ratio. The results also show that the proposed method achieves about 40% more SER reduction compared with that obtained using closed-form analysis for statistical soft error rate estimation (CASSER), the most recently published similar work, in the same experimental conditions. Comparing the runtime of the proposed optimization algorithm with the optimization based on CASSER, it is observed that the proposed method is two orders of magnitude faster than CASSER due to its incremental analysis property.
Autors: Mohsen Raji;Behnam Ghavami;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jan 2017, volume: 25, issue:1, pages: 247 - 260
Publisher: IEEE
 
» Soft-Decision-Aided, Smoothness-Constrained Channel Estimation over Time-Varying Fading Channels With No Channel Model Information
Abstract:
We consider frequency-flat time-varying fading channels with no channel model information (CMI). By introducing the smoothness function to measure the extent of channel fluctuation, we derive a robust soft-decision-aided (SDA) channel estimator based on Pareto optimality of the double-objective optimization of the likelihood function of the received signal sequence and the smoothness constraint of the channel estimates. Compared with the conventional maximum-likelihood-based channel estimators derived under the block-fading assumption, the newly derived SDA-Pareto estimator gives more freedom to the channel estimation process, allowing channel estimates to have controlled variations to track the time-varying channel more closely. Compared with estimators derived based on the maximum a posteriori probability or the minimum mean-square error criterion which require explicit acquisition of the CMI, the SDA-Pareto estimator significantly simplifies the channel measurement process by requiring only a suitable regularization parameter to balance the trade-off between the likelihood function and the smoothness condition. An adaptive algorithm is proposed to adjust the regularization parameter adaptively, enabling an efficient and effective implementation of the SDA-Pareto estimator in practical applications. Simulation studies are provided to demonstrate the advantage of the SDA-Pareto estimator over the conventional estimators in both channel estimation accuracy and error-rate performance.
Autors: Haifeng Yuan;Pooi-Yuen Kam;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 73 - 86
Publisher: IEEE
 
» Software Sophistry and Political Sleight of Hand
Abstract:
Whether to boost sales or advance a political agenda, use of deceptive tactics for manipulating public opinion is pervasive in modern culture.
Autors: Hal Berghel;
Appeared in: Computer
Publication date: Jan 2017, volume: 50, issue:1, pages: 82 - 87
Publisher: IEEE
 
» Solution Processed Amorphous ZnSnO Thin-Film Phototransistors
Abstract:
Amorphous ZnSnO (-ZnSnO) thin films were synthesized by a combustion solution method to fabricate thin-film phototransistors. The -ZnSnO phototransistors are extremely sensitive to UV light, with evident photoelectric effect identified at various gate voltages. The UV sensitivity is rather high ( for the ratio of photocurrent to dark-current) at the off-state, while it is quite low () at the on-state. The device behaviors can completely recover to the original state within 2000 s after switching off the UV light at both on- and off-states. We demonstrate that the UV behaviors of -ZnSnO phototransistors can be well controlled by gate voltages. This paper is expected to provide a fundamental knowledge of performances of amorphous oxide phototransistors for practical applications.
Autors: Lisha Feng;Genyuan Yu;Xifeng Li;Jianhua Zhang;Zhizhen Ye;Jianguo Lu;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jan 2017, volume: 64, issue:1, pages: 206 - 210
Publisher: IEEE
 
» Space-Time and Space-Frequency Block Coded Vector OFDM Modulation
Abstract:
Vector orthogonal frequency division multiplexing (OFDM) is a promising modulation scheme, which allows for a flexible configuration and connects OFDM and single-carrier frequency domain equalization in a unified framework. In this letter, we design Alamouti-like space-time block coded and space-frequency block coded vector OFDM systems. Based on these schemes, we prove that, with two transmit and one receive antenna, the diversity order of the zero-forcing receiver is fixed to 2 over frequency selective fading channels, while that of the minimum mean square error receiver depends on the channel memory length, the vector block size, and the spectral efficiency.
Autors: Jing Han;Geert Leus;
Appeared in: IEEE Communications Letters
Publication date: Jan 2017, volume: 21, issue:1, pages: 204 - 207
Publisher: IEEE
 
» Sparse Unmixing With Dictionary Pruning for Hyperspectral Change Detection
Abstract:
The localization of changes that occur between the images in a multitemporal series is crucial for many applications, ranging from environmental monitoring to military surveillance. In contrast to traditional change detection methods, unmixing-based change detection has been shown to have the important added benefit of providing subpixel-level information on the nature of the changes, instead of only providing the location of the changes. Recently, sparse unmixing has also been introduced to hyperspectral change detection, resulting in a method that circumvents the drawbacks of regular spectral unmixing approaches. Sparse unmixing-based change detection reveals the changes that occur in a multitemporal series, at subpixel level, and in terms of the library spectra and their sparse abundances, and provides enhanced change detection performance, especially when subpixel-level changes have occurred. However, sparse unmixing is generally an ill-conditioned and time-consuming process, especially as the size of the utilized spectral library increases. In this paper, dictionary pruning is exploited for the first time for hyperspectral change detection using sparse unmixing, in order to alleviate the ill-conditioning of the problem and achieve decreased computation times and enhanced change detection performance. Experimental results on both realistic synthetic and real datasets are used to validate the proposed approach.
Autors: Alp Ertürk;Marian-Daniel Iordache;Antonio Plaza;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 321 - 330
Publisher: IEEE
 
» Spatial Modeling of Lidar-Derived Woody Biomass Estimates Collected Along Transects in a Heterogeneous Savanna Landscape
Abstract:
Waveforms from the Ice, Cloud and land Elevation Satellite have successfully estimated footprint-level canopy height and aboveground biomass even in structurally complex savanna ecosystems. However, at the landscape level wall-to-wall maps are preferred since they are more easily integrated with other geospatial data products. We evaluated and compared the utility of inverse distance weighting, cokriging, regression kriging and image segmentation methods to create wall-to-wall maps from footprint-level estimates of biomass across a 13 600-Ha Oak savanna landscape in Santa Clara county, California. The four methods estimated biomass with between 39% (inverse distance weighting) and 66% (image segmentation) of variance explained and RMSE of 42% and 32% of the mean, respectively. When more waveforms were available across or along track to characterize patch biomass with the image segmentation method, 78% of variance in biomass was explained (RMSE = 21% of the mean). Overall, the mean biomass estimated by the four methods did not differ significantly but a visual inspection of the output maps showed marked differences in the ability of each model to mimic the primary variable's landscape-level trend. We conclude that transects of lidar data can be used to create wall-to-wall biomass maps in savannas but the methods require a higher sampling intensity and informative auxiliary data to reproduce the variability of the biomass across the landscape. We recommend that future satellite lidar missions increase the sampling intensity across track so that biomass observations are made and characterized at the scale at which they vary
Autors: David Gwenzi;Michael Andrew Lefsky;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Jan 2017, volume: 10, issue:1, pages: 372 - 384
Publisher: IEEE
 
» Special Article Series on Signal Processing Education via Hands-On and Design Projects [From the Guest Editors]
Abstract:
Autors: Hana Godrich;Arye Nehorai;Ali Tajer;Maria Sabrina Greco;Changshui Zhang;
Appeared in: IEEE Signal Processing Magazine
Publication date: Jan 2017, volume: 34, issue:1, pages: 13 - 15
Publisher: IEEE
 
» Speckle Suppression of OKG Imaging in Highly Turbid Medium Using SC-Assisted Fundamental Frequency
Abstract:
We propose a method to suppress the speckle of optical Kerr gated (OKG) imaging in highly turbid medium using an 800-nm femtosecond laser, in which, the 800-nm fundamental frequency light and the supercontinuum (SC) containing the fundamental frequency are used as the gating beam and imaging beam, respectively. A sequence of images of a test chart hidden behind a highly turbid medium is obtained using the OKG technique. Compared with images obtained with OKG imaging using only the fundamental frequency, the image resolution and contrast of images obtained through OKG imaging using the SC-assisted fundamental frequency are both significantly enhanced.
Autors: Yuhu Ren;Jinhai Si;Wenjiang Tan;Yipeng Zheng;Junyi Tong;Xun Hou;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 106 - 109
Publisher: IEEE
 
» Spectral Characteristics of Narrow-Linewidth High-Power 1180 nm DBR Laser With Surface Gratings
Abstract:
We report narrow-linewidth 1180-nm GaInNAs/GaAs distributed Bragg reflector lasers reaching up to ~500-mW continuous-wave output power at room temperature. The lasers employ surface gratings, which avoided the problematic regrowth and enabled a high side-mode suppression ratio over a relatively large mode-hop-free tuning range. The wavelength tuning rates of 0.1 nm/°C and 1 pm/mA were obtained by changing the mount temperature and the drive current, respectively. The lasers exhibit a narrow emission linewidth (<250 kHz) even at high output power levels. The side-mode suppression ratio is relatively independent of the power level and remains higher than 50 dB even in the vicinity of the roll-off point. An outstanding temperature stability is provided by good carrier confinement in the GaInNAs/GaAs quantum well. A 2000 h burn-in with constant 1.5 A bias at 20 °C improved the output characteristics slightly and did not reveal any failure among the tested components.
Autors: Heikki Virtanen;Antti T. Aho;Jukka Viheriälä;Ville-Markus Korpijärvi;Topi Uusitalo;Mervi Koskinen;Mihail Dumitrescu;Mircea Guina;
Appeared in: IEEE Photonics Technology Letters
Publication date: Jan 2017, volume: 29, issue:1, pages: 114 - 117
Publisher: IEEE
 
» Spectrum Auction for Differential Secondary Wireless Service Provisioning With Time-Dependent Valuation Information
Abstract:
In this paper, we propose a spectrum auction mechanism for secondary spectrum access in cognitive radio networks. Different from existing works in the literature, the time-dependent buyer valuation information is employed in the proposed mechanism so that the primary spectrum owner (PO) can determine more favorable spectrum allocations and pricing functions in order to maximize the expected auction revenue. In addition, to exploit the temporal spectrum reusability, the proposed mechanism allows each secondary wireless user to declare its specific time preferences, including service starting time, delay tolerance, and service length. By further considering the heterogeneities in secondary wireless service provisioning, the proposed mechanism is able to support heterogeneous forms (continuous or disjointed spectrum usages) of secondary spectrum requests. Specifically, at the beginning of the auction frame, secondary wireless users report their different spectrum usage requests along with the bidding prices, while the PO decides a single-step spectrum allocation and calculates the payment for each winner based on not only the received bids but also the known time-dependent valuation information. Theoretical analyses and simulation results show that the proposed auction mechanism can satisfy all desired economic properties, and can improve the spectrum allocation efficiency and auction revenue compared with counterparts.
Autors: Changyan Yi;Jun Cai;Gong Zhang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Jan 2017, volume: 16, issue:1, pages: 206 - 220
Publisher: IEEE
 
» SRLSP: A Face Image Super-Resolution Algorithm Using Smooth Regression With Local Structure Prior
Abstract:
The performance of traditional face recognition systems is sharply reduced when encountered with a low-resolution (LR) probe face image. To obtain much more detailed facial features, some face super-resolution (SR) methods have been proposed in the past decade. The basic idea of a face image SR is to generate a high-resolution (HR) face image from an LR one with the help of a set of training examples. It aims at transcending the limitations of optical imaging systems. In this paper, we regard face image SR as an image interpolation problem for domain-specific images. A missing intensity interpolation method based on smooth regression with a local structure prior (LSP), named SRLSP for short, is presented. In order to interpolate the missing intensities in a target HR image, we assume that face image patches at the same position share similar local structures, and use smooth regression to learn the relationship between LR pixels and missing HR pixels of one position patch. Performance comparison with the state-of-the-art SR algorithms on two public face databases and some real-world images shows the effectiveness of the proposed method for a face image SR in general. In addition, we conduct a face recognition experiment on the extended Yale-B face database based on the super-resolved HR faces. Experimental results clearly validate the advantages of our proposed SR method over the state-of-the-art SR methods in face recognition application.
Autors: Junjun Jiang;Chen Chen;Jiayi Ma;Zheng Wang;Zhongyuan Wang;Ruimin Hu;
Appeared in: IEEE Transactions on Multimedia
Publication date: Jan 2017, volume: 19, issue:1, pages: 27 - 40
Publisher: IEEE
 
» Stability of Positive Switched Linear Systems: Weak Excitation and Robustness to Time-Varying Delay
Abstract:
This article investigates the stability of positive switched linear systems. We start from motivating examples and focus on the case when each switched subsystem is marginally stable (in the sense that all the eigenvalues of the subsystem matrix are in the closed left-half plane with those on the imaginary axis simple) instead of asymptotically stable. A weak excitation condition is first proposed such that the considered positive switched linear system is exponentially stable. An extension to the case without dwell time assumption is also presented. Then, we study the influence of time-varying delay on the stability of the considered positive switched linear system. We show that the proposed weak excitation condition for the delay-free case is also sufficient for the asymptotic stability of the positive switched linear system under unbounded time-varying delay. In addition, it is shown that the convergence rate is exponential if there exists an upper bound for the delay, irrespective of the magnitude of this bound. The motivating examples are revisited to illustrate the theoretical results.
Autors: Ziyang Meng;Weiguo Xia;Karl H. Johansson;Sandra Hirche;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 399 - 405
Publisher: IEEE
 
» Stability of Simple Lumped-Distributed Networks With Negative Capacitors
Abstract:
A majority of non-Foster antenna matching circuits and non-Foster metamaterials are based on a simple parallel combination of positive and negative capacitor. It is known that these networks are stable if the overall “mesh” capacitance is positive. Here, we show that this widely accepted criterion fails if a transmission line of any finite length (different from zero) is inserted between an ideal positive capacitor and an ideal negative capacitor. Such a network is always unstable, which appears to be a serious drawback. However, we also show that a realistic, band-limited negative capacitor can be designed in a way that assures stable operation.
Autors: Josip Loncar;Silvio Hrabar;Damir Muha;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jan 2017, volume: 65, issue:1, pages: 390 - 395
Publisher: IEEE
 
» Stabilization of Delay Systems: Delay-Dependent Impulsive Control
Abstract:
The stabilization problem of delay systems is studied under the delay-dependent impulsive control. The main contributions of this technical note are that, for one thing, it shows that time delays in impulse term may contribute to the stabilization of delay systems, that is, a control strategy which does not work without delay feedback in impulse term can be activated to stabilize some unstable delay systems if there exist some time delay feedbacks; for another, it shows the robustness of impulsive control, that is, the designed control strategy admits the existence of some time delays in impulse term which may do harm to the stabilization. In this technical note, from impulsive control point of view we firstly propose an impulsive delay inequality. Then we apply it to the delay systems which may be originally unstable, and derive some delay-dependent impulsive control criteria to ensure the stabilization of the addressed systems. The effectiveness of the proposed strategy is evidenced by two illustrative examples.
Autors: Xiaodi Li;Shiji Song;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 406 - 411
Publisher: IEEE
 
» Stabilizing Transmission Intervals for Nonlinear Delayed Networked Control Systems
Abstract:
In this note, we consider a nonlinear process with delayed dynamics to be controlled over a communication network in the presence of disturbances and study robustness of the resulting closed-loop system with respect to network-induced phenomena such as sampled, distorted, delayed and lossy data as well as scheduling protocols. For given plant-controller dynamics and communication network properties (e.g., propagation delays and scheduling protocols), we quantify the control performance level (in terms of - gains) as the transmission interval varies. Maximally Allowable Transfer Interval (MATI) labels the greatest transmission interval for which a prespecified - gain is attained. The proposed methodology combines impulsive delayed system modeling with Lyapunov-Razumikhin techniques to allow for MATIs that are smaller than the communication delays. Other salient features of our methodology are the consideration of variable delays, corrupted data and employment of model-based estimators to prolong MATIs. The present stability results are provided for the class of Uniformly Globally Exponentially Stable (UGES) scheduling protocols. The well-known Round Robin (RR) and Try-Once-Discard (TOD) protocols are examples of UGES protocols. Finally, a nonlinear example is provided to demonstrate the benefits of the proposed approach.
Autors: Domagoj Tolić;Sandra Hirche;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jan 2017, volume: 62, issue:1, pages: 488 - 494
Publisher: IEEE
 
» Stable Detection of Movement Intent From Peripheral Nerves: Chronic Study in Dogs
Abstract:
Peripheral nerves provide access to highly processed and segregated neural command signals from the brain that control skeletal muscles. Detecting these signals could provide lifelike, intuitive control of high-degree-of-freedom prosthetic limbs. However, detection of individual fascicle neural activity within a nerve has not yet been accomplished without compromising the nerve. The purpose of this study was to detect fascicular-level neural activity in freely moving animals with nonpenetrating nerve cuff electrodes. Three dogs were implanted with 16-contact flat interface nerve electrodes (FINEs) on the sciatic nerve with total duration of the implant ranging from four to nine months with functional recordings lasting 2.2–7.5 months. The recorded neural activity during normal treadmill walking was used to localize fascicular sources within the nerve and their recovered activity was compared with the ankle movements using binary classification against gait phase. The signal-to-noise ratio (SNR) of the neural signals obtained from the FINE was between 3.65 and 7.59 dB. Postmortem analysis showed that the focal points of the recovered fascicular activity were located within 0.75 0.38 mm from the nearest major fascicles. The two movement intents recovered from each fascicle matched the actual observed ankle movements with overall accuracy of 70%–80% and false crosstalk rate of < 10%. The significant outcome of this study is detecting multiple voluntary fascicular activities with consistent accuracy over time from freely moving animals. It demonstrates the potential of using the FINE in the designs of intuitively controlled advanced prostheses and ultimately improving patient’s quality of life.
Autors: Yazan M. Dweiri;Thomas E. Eggers;Luis E. Gonzalez-Reyes;Joseph Drain;Grant A. McCallum;Dominique M. Durand;
Appeared in: Proceedings of the IEEE
Publication date: Jan 2017, volume: 105, issue:1, pages: 50 - 65
Publisher: IEEE
 
» State Asymmetry Driven State Remapping in Phase Change Memory
Abstract:
Phase change memory (PCM) is one of the most promising candidates to replace DRAM as main memory in deep submicron regime. Regardless of single-level or multiple-level cells, the programming costs to each state exhibit significant asymmetries in latency, energy and endurance. In this paper, we exploit the potential of reducing programming costs in terms of latency, energy, and endurance for PCM through state remapping. First, quantitative programming models are constructed for cost assessments. Then, both dynamic and static remapping schemes are analyzed and compared. The observation that the efficacy of dynamic state remappings is instable motivates us to propose a static remapping technique, which outperforms previous work in cost reduction within much lower implementation overhead. The optimality of the proposed static state remapping is also proved. The evaluation results confirm the efficacy of the proposed state remapping technique in delivering a stable and promising cost reduction in latency, energy, and wear.
Autors: Mengying Zhao;Yuan Xue;Jingtong Hu;Chengmo Yang;Tiantian Liu;Zhiping Jia;Chun Jason Xue;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Jan 2017, volume: 36, issue:1, pages: 27 - 40
Publisher: IEEE
 
» State Estimation for a Class of Piecewise Affine State-Space Models
Abstract:
We propose a filter for piecewise affine state-space models. In each filtering recursion, the true filtering posterior distribution is a mixture of truncated normal distributions. The proposed filter approximates the mixture with a single normal distribution via moment matching. The proposed algorithm is compared with the extended Kalman filter (EKF) in a numerical simulation, where the proposed method obtains, on average, better root mean square error than the EKF.
Autors: Rafael Rui;Tohid Ardeshiri;Henri Nurminen;Alexandre Bazanella;Fredrik Gustafsson;
Appeared in: IEEE Signal Processing Letters
Publication date: Jan 2017, volume: 24, issue:1, pages: 61 - 65
Publisher: IEEE
 
» State Estimation of Micropositioning Stage With Piezoactuators
Abstract:
In this paper, a nonsmooth Kalman filtering method is proposed for noise suppression of micropositioning stages with piezoelectric actuators described by the so-called sandwich model with hysteresis. According to the characteristics of the system, a nonsmooth stochastic state-space equation is constructed. In this model, an autoswitcher is introduced to adapt the nonsmooth operation conditions. Then, the convergence of the novel Kalman filter is discussed. Subsequently, the comparison in simulation between the proposed filtering scheme with the unscented Kalman filter and particle filter is presented. Finally, the experimental results on a micropositioning stage with piezoelectric actuator are illustrated.
Autors: Haifen Li;Yonghong Tan;Ruili Dong;Yanyan Li;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jan 2017, volume: 64, issue:1, pages: 563 - 573
Publisher: IEEE
 
» State of the Journal
Abstract:
Presents the editor's view of the current state of this journal publication.
Autors: David A. Forsyth;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Jan 2017, volume: 39, issue:1, pages: 1 - 2
Publisher: IEEE
 

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