Electrical and Electronics Engineering publications abstract of: 07-2017 sorted by title, page: 2

» A UHF Path Loss Model Using Learning Machine for Heterogeneous Networks
 Abstract:In this paper, we present and evaluate a new propagation model for heterogeneous networks. The designed model is multiband, multienvironment, and is usable for short and long distance. For this research, a measurement campaign was conducted in Tunis (Tunisia) using continuous wave analog technology. It concerns the most used bands (450, 850, 1800, 2100, and 2600 MHz) in rural, suburban, and urban environments. Measurements are split into two independent and random sets. The first one is used for model training, whereas the second is used for model validation. The new model is based on neural networks, uses back propagation algorithm, and obtains its inputs from Standard Propagation Model, to which we have added more parameters such as frequency, environment type, land use distribution, and diffraction loss. Model variables are computed from accurate Digital Terrain Model and Land Used maps with 2-m resolution. The statistical analysis has shown that the developed model is accurate as we obtained the following metrics: 0.235-dB absolute mean error, 6.850-dB standard deviation, and 85% correlation factor. The obtained simulation results are then compared to SPM and ITU-R P.1812-4 prediction, which are taken as reference to highlight the benefit of the new model. Autors: M. Ayadi;A. Ben Zineb;S. Tabbane; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3675 - 3683 Publisher: IEEE
» A Unified Framework for Vehicle Rerouting and Traffic Light Control to Reduce Traffic Congestion
 Abstract:As the number of vehicles grows rapidly each year, more and more traffic congestion occurs, becoming a big issue for civil engineers in almost all metropolitan cities. In this paper, we propose a novel pheromone-based traffic management framework for reducing traffic congestion, which unifies the strategies of both dynamic vehicle rerouting and traffic light control. Specifically, each vehicle, represented as an agent, deposits digital pheromones over its route, while roadside infrastructure agents collect the pheromones and fuse them to evaluate real-time traffic conditions as well as to predict expected road congestion levels in near future. Once road congestion is predicted, a proactive vehicle rerouting strategy based on global distance and local pheromone is employed to assign alternative routes to selected vehicles before they enter congested roads. In the meanwhile, traffic light control agents take online strategies to further alleviate traffic congestion levels. We propose and evaluate two traffic light control strategies, depending on whether or not to consider downstream traffic conditions. The unified pheromone-based traffic management framework is compared with seven other approaches in simulation environments. Experimental results show that the proposed framework outperforms other approaches in terms of traffic congestion levels and several other transportation metrics, such as air pollution and fuel consumption. Moreover, experiments over various compliance and penetration rates show the robustness of the proposed framework. Autors: Zhiguang Cao;Siwei Jiang;Jie Zhang;Hongliang Guo; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Jul 2017, volume: 18, issue:7, pages: 1958 - 1973 Publisher: IEEE
» A Unifying Model for Camera Calibration
 Abstract:This paper proposes a unified theory for calibrating a wide variety of camera models such as pinhole, fisheye, cata-dioptric, and multi-camera networks. We model any camera as a set of image pixels and their associated camera rays in space. Every pixel measures the light traveling along a (half-) ray in 3-space, associated with that pixel. By this definition, calibration simply refers to the computation of the mapping between pixels and the associated 3D rays. Such a mapping can be computed using images of calibration grids, which are objects with known 3D geometry, taken from unknown positions. This general camera model allows to represent non-central cameras; we also consider two special subclasses, namely central and axial cameras. In a central camera, all rays intersect in a single point, whereas the rays are completely arbitrary in a non-central one. Axial cameras are an intermediate case: the camera rays intersect a single line. In this work, we show the theory for calibrating central, axial and non-central models using calibration grids, which can be either three-dimensional or planar. Autors: Srikumar Ramalingam;Peter Sturm; Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence Publication date: Jul 2017, volume: 39, issue:7, pages: 1309 - 1319 Publisher: IEEE
» A Unipolar/Bipolar High-Voltage Pulse Generator Based on Positive and Negative Buck–Boost DC–DC Converters Operating in Discontinuous Conduction Mode
 Abstract:This paper presents a new high-voltage pulse generator, which is based on positive and negative buck-boost (BB) converters fed from a relatively low voltage dc supply. The proposed generator is able to generate unipolar or bipolar high-voltage pulses via operating the BB converters with series or parallel connected outputs respectively using a common input dc source. The components of each converter are rated at half of the pulsed voltage magnitude in the unipolar mode. The converters in the proposed pulse generator operate in discontinuous conduction mode. This enhances system efficiency, as the circuit only operates when it is desired to generate a pulsed output voltage, otherwise the circuit is switched to idle mode with zero current. Detailed illustration of the proposed approach is presented along with a full design of the system components for given output pulse specifications. Finally, simulation and experimental results are presented to validate the proposed concept. Autors: Ahmed A. Elserougi;Ahmed M. Massoud;Shehab Ahmed; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5368 - 5379 Publisher: IEEE
» A Variable Step-Size Normalized Subband Adaptive Filter With a Step-Size Scaler Against Impulsive Measurement Noise
 Abstract:This brief introduces a variable step-size (VSS) normalized subband adaptive filter (NSAF) using a step-size scaler to improve the robustness against impulsive measurement noise. When impulsive measurement noise appears, the step size of the proposed VSS NSAF is scaled down by the step-size scaler, which is suitable for application in the NSAF. This removes a possibility of updating weight estimates based on defective information of the subband output errors due to impulsive measurement noise. In the proposed VSS NSAF, the equations for updating the step size are constructed by interpreting the behavior of the mean square deviation of the conventional NSAF and applying the step-size scaler. The step-size scaler utilizes the sum of the subband output errors, which can be influenced by impulsive measurement noise. Simulations using the proposed VSS NSAF show an excellent transient and steady-state behavior with colored input in impulsive-noise environments. Autors: Junwoong Hur;Insun Song;Poogyeon Park; Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs Publication date: Jul 2017, volume: 64, issue:7, pages: 842 - 846 Publisher: IEEE
» A Variation-Tolerant Near-Threshold Processor With Instruction-Level Error Correction
 Abstract:Timing error resilience is a promising alternative to eliminate margins and improve energy efficiency in subthreshold and near-threshold processors. However, the existing techniques have some limitations, such as uncontaminated architecture registers (ARs), strict timing constraints on error consolidation and propagation, and high design complexity. To address these limitations, a new timing error resilience technique based on sacrificial instruction-level registers is proposed. It dynamically captures and incrementally records the changes of ARs at each instruction boundary. Once a timing error occurs, it only needs to restore the changed ARs to a preerror state. Then, the erroneous instruction can be safely reexecuted. This technique is applicable to different processors. The 32-bit embedded processor employing the proposed technique is demonstrated in a 40-nm CMOS technology. This variation-tolerant processor operates at 27.4 MHz under 0.6 V with 8.7% total area overhead compared with the baseline without timing error resilience. At the same throughput, the proposed technique achieves 44% and 27% energy benefits compared with the baseline and the canary technique, respectively. Autors: Sheng Wang;Chen Chen;Xiao-Yan Xiang;Jian-Yi Meng; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Jul 2017, volume: 25, issue:7, pages: 1993 - 2006 Publisher: IEEE
» A Virtual Inertia Control Strategy for DC Microgrids Analogized With Virtual Synchronous Machines
 Abstract:In a dc microgrid (DC-MG), the dc bus voltage is vulnerable to power fluctuation derived from the intermittent distributed energy or local loads variation. In this paper, a virtual inertia control strategy for DC-MG through bidirectional grid-connected converters (BGCs) analogized with virtual synchronous machine (VSM) is proposed to enhance the inertia of the DC-MG, and to restrain the dc bus voltage fluctuation. The small-signal model of the BGC system is established, and the small-signal transfer function between the dc bus voltage and the dc output current of the BGC is deduced. The dynamic characteristic of the dc bus voltage with power fluctuation in the DC-MG is analyzed in detail. As a result, the dc output current of the BGC is equivalent to a disturbance, which affects the dynamic response of the dc bus voltage. For this reason, a dc output current feedforward disturbance suppressing method for the BGC is introduced to smooth the dynamic response of the dc bus voltage. By analyzing the control system stability, the appropriate virtual inertia control parameters are selected. Finally, simulations and experiments verified the validity of the proposed control strategy. Autors: Wenhua Wu;Yandong Chen;An Luo;Leming Zhou;Xiaoping Zhou;Ling Yang;Yanting Dong;Josep M. Guerrero; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 6005 - 6016 Publisher: IEEE
» A Visualization Tool for Real-Time Dynamic Contingency Screening and Remedial Actions
 Abstract:This paper proposes a real-time visual interactive transient stability screening and remedial action tool that uses an approach based on Lyapunov functions to enable the selection of appropriate remedial actions that stabilize power systems due to large disturbances and cascading failures. At present, there is no effective tool that enables making a well-informed choice from amongst a profusion of remedial action alternatives. Conventionally, transient stability analysis of power system is performed offline to assess the capability of the power system to withstand specific disturbances and to investigate the dynamic response of the power system as the network is restored to normal operation. In this paper, postfault stable and controlling unstable equilibrium points are determined using a homotopy-based approach. Subsequently, stability assessment of the system and the corresponding potential remedial actions are determined from the equilibrium points of the system dynamical model. The real-time transient stability analysis and remedial action algorithm are incorporated with the visualization tool to facilitate interactive decision making in real time. The transient stability analysis and remedial action algorithm, and the visualization tool are demonstrated on several test systems including the equivalent Western Electricity Coordinating Council system and the simplified New England 39 bus test system. Autors: Joydeep Mitra;Mohammed Benidris;Nga Nguyen;Sidart Deb; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3268 - 3278 Publisher: IEEE
» A Wide Detection Range Mercury Ion Sensor Using Si MOSFET Having Single-Walled Carbon Nanotubes as a Sensing Layer
 Abstract:This letter investigates the response of a wide detection range mercury ion sensor based on Si MOSFET having a floating-gate (FG) and a control-gate (CG) in horizontal direction. Single-walled carbon nanotubes (SWNTs) are formed between the FG and the CG by using an inkjet-printing method. The interaction between themercury ions and SWNTs is studied by measuring transient current response (I–t). Conductance change is measured from 1 fM to in saturated transient current region. The measured transient response shows that the drain current () is appreciably changed in pMOSFET sensor and almost notchanged in nMOSFET sensor. By analyzing the conductance change of the pMOSFET sensor with the concentration of mercury ions, it is shown that the work-function of SWNTs increases due to hole doping and the increases as a result. Autors: Jongmin Shin;Yoonki Hong;Meile Wu;Jong-Ho Lee; Appeared in: IEEE Electron Device Letters Publication date: Jul 2017, volume: 38, issue:7, pages: 959 - 962 Publisher: IEEE
» A Wide-Range Capacitive Sensor for Linear and Angular Displacement Measurement
 Abstract:A new capacitive sensor that is suitable for measuring both linear and angular displacements of a shaft over a wide range is reported in this paper. The sensor consists of a cylindrical shaft with a semi-hollow cylinder attached in the center; the shaft is capable of moving along the axis as well as rotating about the axis. Two pairs of semi-hollow-cylindrical electrodes surround the shaft, which is grounded. The amount of linear displacement and rotation is calculated by measuring the change in the capacitance of each of the four electrodes with respect to the shaft. A prototype sensor was constructed and tested; the rms error obtained is 0.6% for the linear displacement and less than 0.6% for the angular displacement. The proposed sensor has potential applications in several robotic, industrial, and automotive fields. Autors: Narendiran Anandan;Boby George; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5728 - 5737 Publisher: IEEE
» A Wideband Multilayer Substrate Integrated Waveguide Cavity-Backed Slot Antenna Array
 Abstract:In this paper, a wideband multilayer substrate integrated waveguide (SIW)-based cavity-backed slot array is proposed. The array element is constructed by stacking five layers of SIW cavity-backed slots and has a wide impedance bandwidth from 18 to 30 GHz. Two different feed networks based on probe coupling and slot coupling are introduced to maintain the wideband characteristic of the proposed element when employed in an array. Two arrays fed by the proposed feed networks are designed, fabricated, and tested. The measured results show that both the arrays employing probe coupling and slot coupling feed networks have a wide impedance bandwidth over 30%. Within the obtained operation bands, good radiation performance is achieved. Moreover, advantages and disadvantages of the proposed two feed networks are discussed. Autors: Yang Cai;Yingsong Zhang;Can Ding;Zuping Qian; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3465 - 3473 Publisher: IEEE
» A Word Line Pulse Circuit Technique for Reliable Magnetoelectric Random Access Memory
 Abstract:A word line pulse (WLP) circuit scheme is proposed toward the implementation of magnetoelectric random access memory (MeRAM). The circuit improves the write error rate (WER) and cell area efficiency by generating a better write pulse compared to conventional bitline pulse (BLP) techniques in terms of the pulse slew rate and amplitude. For the voltage-controlled magnetic anisotropy-induced precessional switching of the magnetic tunnel junction (MTJ), the write pulse shape has a large impact on the switching probability. Typically, a square shape pulse results in higher switching probability compared to that of a triangular shape pulse with long rise and falling edges, since the square shape pulse causes a more stable precessional trajectory of the free layer magnetization by providing a relatively constant in-plane-dominant effective field. Compared to the BLP scheme, the WLP can generate a better square shape pulse by eliminating discharge paths under the pulse condition, using the gain of the access transistor, and effectively diminishing the capacitive loading which needs to be driven. A macrospin compact model of voltage-controlled MTJ shows that the WLP can improve WER by times and allow MeRAM to have four-time improvement in area efficiency of driver circuits compared to the BLP. Autors: Hochul Lee;Albert Lee;Shaodi Wang;Farbod Ebrahimi;Puneet Gupta;Pedram Khalili Amiri;Kang L. Wang; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Jul 2017, volume: 25, issue:7, pages: 2027 - 2034 Publisher: IEEE
» Abnormal Recovery Phenomenon Induced by Hole Injection During Hot Carrier Degradation in SOI n-MOSFETs
 Abstract:This letter investigates an abnormal recovery phenomenon induced by hole injection during hot carrier degradation in silicon-on-insulator n-type metal–oxide–semiconductor transistors. The method by which the hole injection induces the abnormal recovery behavior can be clarified by different hot carrier degradation (HCD) measurement sequences. According to this HCD result, the channel surface energy band is drawn down and the interface defect will be temporarily shielded, an effect caused by the trapped hole. Furthermore, results of different stress voltage experiments indicate that the amount of hole injection is determined by the electric field between the gate and drain. Autors: Ying-Hsin Lu;Ting-Chang Chang;Li-Hui Chen;Yu-Shan Lin;Xi-Wen Liu;Jih-Chien Liao;Chien-Yu Lin;Chen-Hsin Lien;Kuan-Chang Chang;Sheng-Dong Zhang; Appeared in: IEEE Electron Device Letters Publication date: Jul 2017, volume: 38, issue:7, pages: 835 - 838 Publisher: IEEE
» Absorptive Bandstop Filter With Prescribed Negative Group Delay and Bandwidth
 Abstract:An absorptive bandstop filter is proposed and synthesized with prescribed negative group delay (NGD) and negative group delay bandwidth (NBW). It is realized with resistor-loaded coupled-line structures where the NGD can be controlled by the Q-factors of resonators. The resistor of the first section is determined for impedance matching, also providing a negative delay. A prototype is developed, following the proposed design procedure, with NGD = −6.5 ns and NBW= 105 MHz obtained. The proposed method is experimentally validated by the good agreement between the synthesized and measured results. Autors: Liang-Feng Qiu;Lin-Sheng Wu;Wen-Yan Yin;Jun-Fa Mao; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Jul 2017, volume: 27, issue:7, pages: 639 - 641 Publisher: IEEE
» Acceleration of Frequency Sweeping in Eddy-Current Computation
 Abstract:In this paper, a novel method for accelerating frequency sweeping in eddy-current calculation using finite-element method is presented. Exploiting the fact that between adjacent frequencies, the eddy-current distributions are similar, an algorithm is proposed to accelerate the frequency sweeping computation. The solution of the field quantities under each frequency, which involves solving a system of linear equations using the conjugate gradients squared (CGS) method, is accelerated by using an optimized initial guess—the final solution from the previous frequency. Numerical tests show that this treatment could speed up the convergence of the CGS solving process, i.e., reduced number of iterations reaching the same relative residuals or reaching smaller residuals with the same iteration number. Autors: Mingyang Lu;Anthony Peyton;Wuliang Yin; Appeared in: IEEE Transactions on Magnetics Publication date: Jul 2017, volume: 53, issue:7, pages: 1 - 8 Publisher: IEEE
» Acceleration of Rotating Plasma Flows in Crossed Magnetic Fields
 Abstract:In the previous investigations, an intermode exchange was used to demonstrate the transfer of energy and momentum into using different kinematic degrees of freedom. This paper examines using a hydrodynamic approach using a cold, neutral flow in a rotating cylindrical plasma column using crossed magnetic fields. Results show that the twirling plasma flow in a cylindrical vortex can be accelerated in an axial direction, thereby resulting an energy/momentum transfer in the axial direction. These results are analogous to the creation of a plasma thruster using this effect. Autors: Alexander R. Karimov;Paul A. Murad; Appeared in: IEEE Transactions on Plasma Science Publication date: Jul 2017, volume: 45, issue:7, pages: 1710 - 1716 Publisher: IEEE
» Accurate Attitude Estimation of a Moving Land Vehicle Using Low-Cost MEMS IMU Sensors
 Abstract:This paper presents a novel Kalman filter for the accurate determination of a vehicle’s attitude (pitch and roll angles) using a low-cost MEMS inertial measurement unit (IMU) sensor, comprising a tri-axial gyroscope and a tri-axial accelerometer. Currently, vehicles deploy expensive gyroscopes for attitude determination. A low-cost MEMS gyro cannot be used because of the drift problem. Typically, an accelerometer is used to correct this drift by measuring the attitude from gravitational acceleration. This is, however, not possible in vehicular applications, because accelerometer measurements are corrupted by external accelerations produced due to vehicle movements. In this paper, we show that vehicle kinematics allow the removal of external accelerations from the lateral and vertical axis accelerometer measurements, thus giving the correct estimate of lateral and vertical axis gravitational accelerations. An estimate of the longitudinal axis gravitational acceleration can then be obtained by using the vector norm property of gravitational acceleration. A Kalman filter is designed, which implements the proposed solution and uses the accelerometer in conjunction with the gyroscope to accurately determine the attitude of a vehicle. Hence, this paper enables the use of extremely low-cost MEMS IMU for accurate attitude determination in vehicular domain for the first time. The proposed filter was tested by both simulations and experiments under various dynamic conditions and results were compared with five existing methods from the literature. The proposed filter was able to maintain sub-degree estimation accuracy even under very severe and prolonged dynamic conditions. To signify the importance of the achieved accuracy in determining accurate attitude, we investigated its use in two vehicular applications: vehicle yaw estimate and vehicle location estimate by dead reckoning and showed the performance improvements obtained by the proposed filter. Autors: Hamad Ahmed;Muhammad Tahir; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Jul 2017, volume: 18, issue:7, pages: 1723 - 1739 Publisher: IEEE
» Accurate Determination of Induction Machine Torque and Current Versus Speed Characteristics
 Abstract:The determination of induction machine torque and current speed characteristics relies on methods based on either direct testing or calculation, using a machine equivalent circuit (EC). Both methods may lead to significant errors. As a contribution to a still open discussion, this paper presents the challenges encountered using these methods and an approach is presented in this paper to overcome the inherent challenges. The proposed approach considers saturation, and compensates for skin effect and machine temperature to improve accuracy. Five induction motors of different pole pairs were analyzed and tested to provide the understanding of the underlying issues of predicting torque and current characteristics of induction machines. The findings indicate that, for direct testing, multiple data points closer to nominal voltage are required. In the case of EC modeling, proper correction of the model for temperature and saturation leads to improved prediction of the torque characteristics of general purpose induction machines. Autors: Emmanuel B. Agamloh;Andrea Cavagnino;Silvio Vaschetto; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3285 - 3294 Publisher: IEEE
» Accurate Estimation of CMOS Power Consumption Considering Glitches by Using Waveform Lookup
 Abstract:Gate-level power estimation methodologies are often considered as a sign-off level reference for digital circuit design. Nevertheless, when gate delays and related effects like glitches are taken into account, commercial state-of-the-art gate-level power estimators show surprisingly large estimation errors. Following an analysis of factors causing these inaccuracies, a novel gate-level power estimation approach is proposed, which combines lookup-based macromodels with the accuracy of analog signal waveforms and achieves significantly better results under the influence of glitches. Autors: Michael Meixner;Tobias G. Noll; Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs Publication date: Jul 2017, volume: 64, issue:7, pages: 787 - 791 Publisher: IEEE
» Achievable Rate With Closed-Form for SISO Channel and Broadcast Channel in Visible Light Communication Networks
 Abstract:In this paper, we study the channel capacity and region for both the single-input-single-output (SISO) channel and broadcast channel (BC) in visible light communication (VLC) systems, under the peak optical power, average optical power, and electrical power constraints. Under the condition that the input signal is continuous, we develop a closed-form lower bound (termed ABG lower bound) and an upper bound for SISO channel using the entropy power inequality and Lagrangian function method. Moreover, a closed-form achievable rate region (termed ABG region) is derived for the VLC BC. Furthermore, for a multi-light-emitting diode and multiuser VLC system, we propose an achievable rate expression for each user, and then investigate a VLC BC beamforming design problem by utilizing the obtained closed-form expression. The beamforming design problem is shown to be NP-hard, and we transform this problem into a convex semidefinite program by using the semidefinite relaxation technique. Finally, numerical results are presented to evaluate the performance of the proposed ABG lower bound/region and the beamforming design. Autors: Shuai Ma;Ruixin Yang;Hang Li;Zhi-Long Dong;Huaxi Gu;Shiyin Li; Appeared in: Journal of Lightwave Technology Publication date: Jul 2017, volume: 35, issue:14, pages: 2778 - 2787 Publisher: IEEE
» Achievable Rates for Gaussian Degraded Relay Channels With Non-Vanishing Error Probabilities
 Abstract:This paper revisits the Gaussian degraded relay channel, where the link that carries information from the source to the destination is a physically degraded version of the link that carries information from the source to the relay. The source and the relay are subject to expected power constraints. The -capacity of the channel is characterized and it is strictly larger than the capacity for any , which implies that the channel does not possess the strong converse property. The proof of the achievability part is based on several key ideas: block Markov coding, which is used in the classical decode-forward strategy, power control for Gaussian channels under expected power constraints, and a careful scaling between the block size and the total number of block uses. The converse part is proved by first establishing two non-asymptotic lower bounds on the error probability, which are derived from the type-II errors of some binary hypothesis tests. Subsequently, each lower bound is simplified by conditioning on an event related to the power of some linear combination of the codewords transmitted by the source and the relay. Lower and upper bounds on the second-order term of the optimal coding rate are also obtained. Autors: Silas L. Fong;Vincent Y. F. Tan; Appeared in: IEEE Transactions on Information Theory Publication date: Jul 2017, volume: 63, issue:7, pages: 4183 - 4201 Publisher: IEEE
» Achieving a Large Gain-Bandwidth Product From a Compact Antenna
 Abstract:This paper presents a method to achieve high gain (>20 dBi) and wide bandwidth (>55%) from a compact antenna that is less than one wavelength tall and only in diameter at the lowest operating frequency. The antenna comprises of an optimized single-layer superstrate, made out of four dielectric sections, and a ground plane, which are separated by an air cavity. The permittivity and thickness of the dielectric sections decrease in the transverse direction. Two-step optimization method was implemented employing a customized full-wave optimizer to optimize the width and thickness of each dielectric section in the superstrate, while maintaining a fixed overall diameter of the antenna. This optimization results in an antenna with a high gain and a large 3-dB gain bandwidth, without compromising on antenna footprint. A prototype of the new antenna having a superstrate with stepped thickness was fabricated and tested. It exhibits a measured peak broadside directivity and a peak realized gain of 20.7 and 20.2 dBi, respectively. Its measured gain-bandwidth product of 5969 and directivity-bandwidth product (DBP) of 6580 are almost three times the best figures for resonant cavity antennas (RCAs). The total area of the new antenna prototype is and its overall height is at the lowest operating frequency. It is significantly more compact and its DBP per unit area and aperture efficiency are significantly greater than those of lens-based antennas. Its measured 3-dB gain bandwidth of 57% is unprecedented for high-gain short antennas, including RCAs. Moreover, over the entire bandwidth, sidelobe levels of the antenna are around - 12;12 and −21 dB in the E- and H-planes, respectively. Autors: Affan Aziz Baba;Raheel M. Hashmi;Karu P. Esselle; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3437 - 3446 Publisher: IEEE
» Achieving Low-Recovery Time in AlGaN/GaN HEMTs With AlN Interlayer Under Low- Noise Amplifiers Operation
 Abstract:Three transistors with different AlGaN/GaN interface designs (sharp interface, standard interface, and an extra AlN interlayer) were studied in-depth under conditions mimicking low-noise amplifiers (LNAs) operation. A new measurement setup, analog to LNAs operation condition, is established to measure recovery time on device level. For the first time, a direct relationship between the recovery time and the design of AlGaN/GaN interface is revealed in devices with Carbon doping buffer in this letter. An extremely low-recovery time is demonstrated in the transistor with an AlN interlayer. Both transistors without an AlN interlayer exhibit severe gain and drain current degradation after pulsed input stress. The transistor with a sharp interface shows a recovery time around 10 ms, whereas the transistorwith a standard interface shows even much longer recovery time. These results imply that AlN interlayer, which can effectively block the injection of hot electrons to AlGaN bulk or surface traps, is highly preferred in systems where LNAs need to function promptly after an input overdrive. Autors: Tongde Huang;Olle Axelsson;Johan Bergsten;Mattias Thorsell;Niklas Rorsman; Appeared in: IEEE Electron Device Letters Publication date: Jul 2017, volume: 38, issue:7, pages: 926 - 928 Publisher: IEEE
» Active Harmonic Reduction Using DC-Side Current Injection Applied in a Novel Large Current Rectifier Based on Fork-Connected Autotransformer
 Abstract:In this paper, a novel large current rectifier using the fork-connected autotransformer and dc-side current injection method is proposed. The fork-connected autotransformer outputs two sets of three-phase voltages with 60° phase difference, and feeds two three-phase half-wave rectifiers. Compared with the isolated line-frequency transformer, the proposed autotransformer has lower kilovoltampere (kVA) rating under the same load power. An optimal designed single-phase full-bridge inverter is used to inject the compensation currents into the dc side of the two three-phase half-wave rectifier, which can reduce the harmonics in input line current to be an acceptable level. The kVA rating of the single-phase full-bridge inverter is very lower, and the proposed large current rectifier draws nearly sinusoidal currents from the ac main after using the dc-side injection. A 4 kW prototype is set up to validate the theoretical analysis and evaluate the performance. Autors: Fangang Meng;Xiaona Xu;Lei Gao;Chunwei Cai; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5250 - 5264 Publisher: IEEE
» Activity Probability-Based Performance Analysis and Contention Control for IEEE 802.11 WLANs
 Abstract:In this paper, we develop a contention window (CW) control scheme for practical IEEE 802.11 wireless local area networks (WLANs) that have node heterogeneity in terms of the traffic load, transmission rate, and packet size. We introduce activity probability, i.e., the probability that a node contends for medium access opportunities at a given time. We then newly develop a performance analysis model that enables analytic estimation on the contention status including the collision probability, collision time, back-off time, and throughput with comprehensive consideration of node heterogeneity. Based on the newly developed model, we derive the theoretically ideal contention status, and develop a CW control scheme that achieves the ideal contention status in an average sense. We perform extensive NS-3 simulations and real testbed experiments for evaluation of both the proposed performance analysis model and CW control scheme. The results show that the proposed model provides accurate prediction on the contention status, and the proposed CW control scheme achieves considerable throughput improvement compared to the existing schemes which do not comprehensively consider node heterogeneity. Autors: Junsu Choi;Seongho Byeon;Sunghyun Choi;Kwang Bok Lee; Appeared in: IEEE Transactions on Mobile Computing Publication date: Jul 2017, volume: 16, issue:7, pages: 1802 - 1814 Publisher: IEEE
 Abstract:The hybrid filter bank (HFB) has been considered as a promising solution for high-speed, high-resolution analog-to-digital conversion. In this letter, we propose an adaptable HFB architecture of which the conversion band can be adapted according to the frequency band of interest, e.g., the entire working band of a wideband receiver or a subband with an arbitrary spectrum position. Furthermore, we propose a strategy based on the adaptable HFB for a wideband receiver to efficiently fulfill different tasks. For spectrum sensing, the entire wideband conversion HFB is used. While for subband signal receiving, the subband conversion HFB is utilized. Examples show that compared with the existing HFB studies in which the wanted subband signal is extracted from the digitalized entire working band, the proposed strategy can significantly simplify the receiving process for subband signals, because the subband conversion HFB has a filtering effect on the input spectrum. Autors: Xu Liu;Wei Li;Jibo Wei;Longwang Cheng; Appeared in: IEEE Communications Letters Publication date: Jul 2017, volume: 21, issue:7, pages: 1525 - 1528 Publisher: IEEE
» Adaptive Bit Allocation for Consistent Video Quality in Scalable High Efficiency Video Coding
 Abstract:Scalable video coding (SVC) is a coding paradigm that allows once-encoded video content to be used in diverse scenarios. SVC-coded videos can be transmitted and rendered at specified bitrates according to network bandwidth and end device requirements. In this paper, an adaptive bit allocation algorithm is proposed for the emerging scalable High Efficiency Video Coding (SHVC) standard. The bit budget at the group-of-pictures level is allocated according to buffer occupancy. Picture complexity, measured using the predicted mean absolute difference (MAD), buffer occupancy, and hierarchical level, is proposed for regulating the bitrate at the picture level. The MAD of the current picture is predicted using a novel mean prediction error (MPE) model, which is obtained from the advanced motion vector prediction, and the test zone search specified in SHVC and the associated reference software of SHVC. Moreover, MPE is used to determine the number of assigned bits at the coding-tree-unit level. The bit budget of each level is incorporated with the model for computing the required quantization parameter. Experimental results reveal that the proposed method achieves accurate bitrates with enhanced and consistent visual quality and more satisfactorily controls buffer occupancy compared with the state-of-the-art approaches reported in the literature. Autors: Shih-Hsuan Yang;Phuong Binh Vo; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Jul 2017, volume: 27, issue:7, pages: 1555 - 1567 Publisher: IEEE
» Adaptive Dynamic Programming-Based Optimal Control Scheme for Energy Storage Systems With Solar Renewable Energy
 Abstract:In this paper, a novel optimal energy storage control scheme is investigated in smart grid environments with solar renewable energy. Based on the idea of adaptive dynamic programming (ADP), a self-learning algorithm is constructed to obtain the iterative control law sequence of the battery. Based on the data of the real-time electricity price (electricity rate in brief), the load demand (load in brief), and the solar renewable energy (solar energy in brief), the optimal performance index function, which minimizes the total electricity cost and simultaneously extends the battery's lifetime, is established. A new analysis method of the iterative ADP algorithm is developed to guarantee the convergence of the iterative value function to the optimum under iterative control law sequence for any time index in a period. Numerical results and comparisons are presented to illustrate the effectiveness of the developed algorithm. Autors: Qinglai Wei;Guang Shi;Ruizhuo Song;Yu Liu; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5468 - 5478 Publisher: IEEE
» Adaptive Energy Management System Based on a Real-Time Model Predictive Control With Nonuniform Sampling Time for Multiple Energy Storage Electric Vehicle
 Abstract:The performance of a dual energy storage electric vehicle system mainly depends on the quality of its power and energy managements. A real-time management strategy supported by a model predictive control (MPC) using the nonuniform sampling time concept is developed and fully addressed in this paper. First, the overall multiple energy storage powertrain model including its inner control layer is represented with the energetic macroscopic representation and used to introduce the energy strategy level. The model of the system with its inner control layer is translated into the state-space domain in order to develop an MPC approach. The management algorithm based on mixed short- and long-term predictions is compared to rule-based and constant sampling time MPC strategies in order to assess its performance and its ability to be used in a real vehicle. The real-time simulation results indicate that, compared to other strategies, the proposed MPC strategy can balance the power and the energy of the dual energy storage system more effectively, and reduce the stress on batteries. Moreover, battery and supercapacitor key variables are kept within safety limits, increasing the lifetime of the overall system. Autors: Oleg Gomozov;João Pedro F. Trovão;Xavier Kestelyn;Maxime R. Dubois; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Jul 2017, volume: 66, issue:7, pages: 5520 - 5530 Publisher: IEEE
» Adaptive Importance Sampling: The past, the present, and the future
 Abstract:A fundamental problem in signal processing is the estimation of unknown parameters or functions from noisy observations. Important examples include localization of objects in wireless sensor networks [1] and the Internet of Things [2]; multiple source reconstruction from electroencephalograms [3]; estimation of power spectral density for speech enhancement [4]; or inference in genomic signal processing [5]. Within the Bayesian signal processing framework, these problems are addressed by constructing posterior probability distributions of the unknowns. The posteriors combine optimally all of the information about the unknowns in the observations with the information that is present in their prior probability distributions. Given the posterior, one often wants to make inference about the unknowns, e.g., if we are estimating parameters, finding the values that maximize their posterior or the values that minimize some cost function given the uncertainty of the parameters. Unfortunately, obtaining closed-form solutions to these types of problems is infeasible in most practical applications, and therefore, developing approximate inference techniques is of utmost interest. Autors: Monica F. Bugallo;Victor Elvira;Luca Martino;David Luengo;Joaquin Miguez;Petar M. Djuric; Appeared in: IEEE Signal Processing Magazine Publication date: Jul 2017, volume: 34, issue:4, pages: 60 - 79 Publisher: IEEE
» Adaptive In-Cache Streaming for Efficient Data Management
 Abstract:The design of adaptive architectures is frequently focused on the sole adaptation of the processing blocks, often neglecting the power/performance impact of data transfers and data indexing in the memory subsystem. In particular, conventional address-based models, supported on cache structures to mitigate the memory wall problem, often struggle when dealing with memory-bound applications or arbitrarily complex data patterns that can be hardly captured by prefetching mechanisms. Stream-based techniques have proven to efficiently tackle such limitations, although not well-suited to handle all types of applications. To mitigate the limitations of both communication paradigms, an efficient unification is herein proposed, by means of a novel in-cache stream paradigm, capable of seamlessly adapting the communication between the address-based and stream-based models. The proposed morphable infrastructure relies on a new dynamic descriptor graph specification, capable of handling regular arbitrarily complex data patterns, which is able to improve the main memory bandwidth utilization through data reutilization and reorganization techniques. When compared with state-of-the-art solutions, the proposed structure offers higher address generation efficiency and achievable memory throughputs, and a significant reduction of the amount of data transfers and main memory accesses, resulting on average in 13 times system performance speedup and in 245 times energy-delay product improvement, when compared with the previous implementations. Autors: Nuno Neves;Pedro Tomás;Nuno Roma; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Jul 2017, volume: 25, issue:7, pages: 2130 - 2143 Publisher: IEEE
» Adaptive Local Movement Modeling for Robust Object Tracking
 Abstract:In this paper, we present a new strategy for modeling the motion of local patches for single-object tracking that can be seamlessly applied to most part-based trackers in the literature. The proposed adaptive local movement modeling method is able to model the local movement distribution of the image patches defining the object to track and the reliability of each image patch. Given the output of a base tracking algorithm, a Gaussian mixture model (GMM) is first used to model the distribution of the movement of local patches relative to the center of gravity of the tracked object. Then, the GMM is combined with the chosen base tracker in a boosting framework, which gives an efficient integrated scheme for the tracking task. This provides a robust procedure to detect outliers in the local motion of the patches. The algorithm is highly configurable with the possibility to change the number of local patches used for tracking and to adapt to the variations of the tracked object. The extensive tracking results on standard data sets show that equipping state-of-the-art trackers with our technique remarkably improves their performance. Autors: Baochang Zhang;Zhigang Li;Alessandro Perina;Alessio Del Bue;Vittorio Murino;Jianzhuang Liu; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Jul 2017, volume: 27, issue:7, pages: 1515 - 1526 Publisher: IEEE
» Adaptive Notch Filter-Based Multipurpose Control Scheme for Grid-Interfaced Three-Phase Four-Wire DG Inverter
 Abstract:The power electronic converter and its control system form an integral part of distributed generation (DG) systems interfacing renewable energy sources to the utility network. This paper proposes an adaptive notch filter-based multipurpose control scheme for grid interfacing DG inverter under corrupted grid conditions. The proposed control scheme uses a frequency adaptive sequence components extractor, which is capable of extracting instantaneous symmetrical components and harmonic components of three-phase signals. The DG inverter in this study consists of three single-phase voltage source inverters with common dc bus and coupled to utility grid via three single-phase transformers. The proposed control scheme enables the DG inverter to perform multiple tasks such as reference power injection to grid, low voltage ride through, load reactive power support, and compensation of harmonic, unbalanced, and neutral currents. The efficacy of the proposed control scheme is evaluated through MATLAB/Simulink simulations and experimentally verified using a hardware-in-the-loop based system. Autors: Raja Sekhara Reddy Chilipi;Naji Al Sayari;Khalifa Hassan Al Hosani;Abdul R. Beig; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 4015 - 4027 Publisher: IEEE
» Adaptive Optimal Stochastic Control of Delay-Tolerant Networks
 Abstract:Optimal stochastic control of delay tolerant networks is studied in this paper. First, the structure of optimal two-hop forwarding policies is derived. In order to be implemented, such policies require knowledge of certain global system parameters such as the number of mobiles or the rate of contacts between mobiles. But, such parameters could be unknown at system design time or may even change over time. In order to address this problem, adaptive policies are designed that combine estimation and control: based on stochastic approximation techniques, such policies are proved to achieve optimal performance in spite of lack of global information. Furthermore, the paper studies interactions that may occur in the presence of several DTNs which compete for the access to a gateway node. The latter problem is formulated as a cost-coupled stochastic game and a unique Nash equilibrium is found. Such equilibrium corresponds to the system configuration in which each DTN adopts the optimal forwarding policy determined for the single network problem. Autors: Eitan Altman;Francesco De Pellegrini;Daniele Miorandi;Giovanni Neglia; Appeared in: IEEE Transactions on Mobile Computing Publication date: Jul 2017, volume: 16, issue:7, pages: 1815 - 1829 Publisher: IEEE
» Adaptive SM-MIMO for mmWave Communications With Reduced RF Chains
 Abstract:In this paper, a novel multiple-input multiple-output (MIMO) transmission scheme, termed as receive antenna selection (RAS)-aided spatial modulation MIMO (SM-MIMO), is proposed for millimeter-wave (mmWave) communications. It employs the spatial modulation (SM) concept and the RAS technique to tackle the costs of the multiple radio frequency (RF) chains at both link ends. Moreover, we develop a pair of RAS algorithms for the proposed mmWave RAS-SM scheme based on the capacity maximization (max-capacity) and the bit-error rate (BER) minimization criteria, which are formulated as two combinatorial optimization problems. The theoretical gradients of the capacity and the BER with respect to RAS variables are derived and the convexities of these problems are discussed. Furthermore, a novel iterative algorithm through jointly designing the log-barrier algorithm (LbA) and the simplified conjugate gradient method is proposed for RAS optimization. Our simulation results show that the proposed RAS-SM schemes are capable of achieving considerable performance gains over conventional norm-based and eigenvalue-based schemes in mmWave MIMO channels, while avoiding an overwhelming complexity imposed by exhaustive search. Autors: Ping Yang;Yue Xiao;Yong Liang Guan;Zilong Liu;Shaoqian Li;Wei Xiang; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Jul 2017, volume: 35, issue:7, pages: 1472 - 1485 Publisher: IEEE
» Adaptive Source Localization Based Station Keeping of Autonomous Vehicles
 Abstract:We study the problem of driving a mobile sensory agent to a target whose location is specified only in terms of the distances to a set of sensor stations or beacons. The beacon positions are unknown, but the agent can continuously measure its distances to them as well as its own position. This problem has two particular applications: (1) capturing a target signal source whose distances to the beacons are measured by these beacons and broadcasted to a surveillance agent, (2) merging a single agent to an autonomous multi-agent system so that the new agent is positioned at desired distances from the existing agents. The problem is solved using an adaptive control framework integrating a parameter estimator producing beacon location estimates, and an adaptive motion control law fed by these estimates to steer the agent toward the target. For location estimation, a least-squares adaptive law is used. The motion control law aims to minimize a convex cost function with unique minimizer at the target location, and is further augmented for persistence of excitation. Stability and convergence analysis is provided, as well as simulation results demonstrating performance and transient behavior. Autors: Samet Güler;Barış Fidan;Soura Dasgupta;Brian D. O. Anderson;Iman Shames; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3122 - 3135 Publisher: IEEE
» Adaptive Time-Switching Based Energy Harvesting Relaying Protocols
 Abstract:Considering a dual-hop energy-harvesting (EH) relaying system, this paper advocates novel relaying protocols based on adaptive time-switching (TS) for amplify-and-forward and decode-and-forward modes, respectively. The optimal TS factor is first studied, which is adaptively adjusted based on the dual-hop channel state information (CSI), accumulated energy, and threshold signal-to-noise ratio (SNR), to achieve the maximum throughput efficiency per block. To reduce the CSI overhead at the EH relay, a low-complexity TS factor design is presented, which only needs single-hop CSI to determine the TS factor. Theoretical results show that, in comparison with the conventional solutions, the proposed optimal/low-complexity TS factor can achieve higher limiting throughput efficiency for sufficiently small threshold SNR. As the threshold SNR approaches infinity, the throughput efficiency of the proposed optimal/low-complexity TS factor tends to zero in a much slower pace than that of the conventional solutions. Simulation results are presented to corroborate the proposed methodology. Autors: Haiyang Ding;Xiaodong Wang;Daniel Benevides da Costa;Yunfei Chen;Fengkui Gong; Appeared in: IEEE Transactions on Communications Publication date: Jul 2017, volume: 65, issue:7, pages: 2821 - 2837 Publisher: IEEE
» Adaptive Transmit-Side Equalization for Serial Electrical Interconnects at 100 Gb/s Using Duobinary
 Abstract:The ever-increasing demand for more efficient data communication calls for new, advanced techniques for high speed serial communication. Although newly developed systems are setting records, off-line determination of the optimal equalizer settings is often needed. Well-known adaptive algorithms are mainly applied for receive-side equalization. However, transmit-side equalization is desirable for its reduced linearity requirements. In this paper, an adaptive sign–sign least mean square equalizer algorithm is developed applicable for an analog transmit-side feed-forward equalizer (FFE) capable of transforming non-return-to-zero modulation to duobinary (DB) modulation at the output of the channel. In addition to the derivation of the update strategy, extra algorithms are developed to cope with the difficult transmit–receive synchronization. Using an analog six tap bit-spaced equalizer, the algorithm is capable of optimizing DB communication of 100Gb/s over 1.5-m Twin-Ax cable. Both simulations and experimental results are presented to prove the capabilities of the algorithm demonstrating automated determination of FFE parameters, such that error-free communication is obtained (BER using PRBS9). Autors: Michiel Verplaetse;Timothy De Keulenaer;Arno Vyncke;Ramses Pierco;Renato Vaernewyck;Joris Van Kerrebrouck;Johan Bauwelinck;Guy Torfs; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Jul 2017, volume: 64, issue:7, pages: 1865 - 1876 Publisher: IEEE
» Add-On Module of Active Disturbance Rejection for Set-Point Tracking of Motion Control Systems
 Abstract:Active disturbance rejection control (ADRC) as a standalone motion solution has been made available in recent years on various industrial platforms. The idea of ADRC, however, can be integrated with the existing control technologies seamlessly, as shown in this paper. A modularized ADRC design is proposed in this particular work for set-point tracking task in motion control, such that better uncertainty rejection can be obtained without any change in the existing proportional-derivative control with a linear observer. It is proven that a certain extended state of the observer, i.e., the integration of the observer error, can serve as an estimation for the “total disturbance” in low-frequency range by only tuning the augmented gain. This enables the estimation and cancellation of the “total disturbance” to be incorporated into the existing control loop. Also, a comparison between the methods with and without such “module” is discussed. The proposed ADRC is implemented and validated experimentally using a laboratory manipulator, where the desired set-point tracking performance in position control is achieved under unknown mass variations and sudden external disturbances. Autors: Wenchao Xue;Rafal Madonski;Krzysztof Lakomy;Zhiqiang Gao;Yi Huang; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 4028 - 4040 Publisher: IEEE
» Advanced Control Strategies of PMSG-Based Wind Turbines for System Inertia Support
 Abstract:This paper investigates two novel control strategies that enable system inertia supports by permanent magnet synchronous generator (PMSG) wind turbines during transient events. The first strategy seeks to provide inertia support to the system through simultaneous utilization of dc-link capacitor energy, and wind turbine (WT) rotor kinetic energy (KE). The second strategy supports system inertia through orderly exerting dc-link capacitor energy of WT and then WT rotor KE via a cascading control scheme. Both strategies can effectively provide system inertia support by fully utilizing WT's own potentials, while the second strategy distinguishes itself by minimizing its impacts on wind energy harvesting. Case studies of one synchronous generator connected with a PMSG-based WT considering sudden load variations have been studied to validate and compare the two proposed strategies on providing rapid inertia response for the system. Autors: Yujun Li;Zhao Xu;Kit Po Wong; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 3027 - 3037 Publisher: IEEE
» Advanced Data Exploitation in Speech Analysis: An overview
 Abstract:With recent advances in machine-learning techniques for automatic speech analysis (ASA)-the computerized extraction of information from speech signals-there is a greater need for high-quality, diverse, and very large amounts of data. Such data could be game-changing in terms of ASA system accuracy and robustness, enabling the extraction of feature representations or the learning of model parameters immune to confounding factors, such as acoustic variations, unrelated to the task at hand. However, many current ASA data sets do not meet the desired properties. Instead, they are often recorded under less than ideal conditions, with the corresponding labels sparse or unreliable. Autors: Zixing Zhang;Nicholas Cummins;Bjoern Schuller; Appeared in: IEEE Signal Processing Magazine Publication date: Jul 2017, volume: 34, issue:4, pages: 107 - 129 Publisher: IEEE
» Aerospace Needs, Microelectronics, and the Quest for Reliability: 1962–1975 [Scanning Our Past]
 Abstract:This computer system is not intended for use in the operation of nuclear facilities, aircraft navigation or communications systems, or air traffic control machines, or for any other uses where the failure of the computer system could lead to death, personal injury, or severe environmental damage.—Apple Computer, Inc., Macbook Users Guide, 2006, p. 109. Autors: Paul E. Ceruzzi; Appeared in: Proceedings of the IEEE Publication date: Jul 2017, volume: 105, issue:7, pages: 1456 - 1465 Publisher: IEEE
» Affine Invariant Description and Large-Margin Dimensionality Reduction for Target Detection in Optical Remote Sensing Images
 Abstract:A novel target detection method based on affine invariant interest point detection, feature encoding, and large-margin dimensionality reduction (LDR) is proposed for optical remote sensing images. First, four types of interest point detectors are introduced, and their performance in extracting low-level affine invariant descriptors using affine shape estimation is compared. Such a description can deal with significant affine transformations, including viewpoints. Second, feature encoding, which extends bag-of-words (BOW) by encoding high-order statistics, is selected to generate mid-level representation. Finally, LDR based on the large-margin constraint and stochastic subgradient is introduced to make the high-dimensional mid-level representation applicable for target detection. The experiments on aircraft and vehicle detections illustrate the effectiveness of the affine invariant description and LDR (compared with principal component analysis) in improving the detection performance. The experiments also demonstrate the effectiveness of the proposed method compared with popular approaches including Gabor, HOG, LBP, BOW, and R-CNN. Autors: Lihong Wan;Laiwen Zheng;Hong Huo;Tao Fang; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Jul 2017, volume: 14, issue:7, pages: 1116 - 1120 Publisher: IEEE
» Agile All-Digital DPD Feedback Loop
 Abstract:This paper presents an original agile all-digital feedback loop receiver system for power amplifier (PA) linearization using digital predistortion (DPD). The proposed feedback loop is based on a radio-frequency pulse-width modulation analog-to-digital converter. For proof of concept, the system was implemented using a single field programmable gate array chip. Additionally, the system is also presented in a remote version, suitable for future centralized radio access network, in which the DPD can be performed in a central unit, far from the PA. Measurement results of important DPD metrics, such as adjacent channel power ratio (ACPR) and error vector magnitude (EVM), are presented and evaluated to verify the correct functioning of the proposed feedback loop. The obtained results demonstrate the system’s agility and high analog input bandwidth from a few megahertzes up to almost 4 GHz, while maintaining the LTE ACPR and EVM requirements. Autors: André Prata;Jorge C. Santos;Arnaldo S. R. Oliveira;Nuno Borges Carvalho; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Jul 2017, volume: 65, issue:7, pages: 2476 - 2484 Publisher: IEEE
» AI to ensure fewer UFOs
 Abstract:Is it a bird? A plane? Or is it a remotely operated quadrotor conduct ing surveillance or preparing to drop a deadly payload? Human observers won’t have to guess—or keep their eyes glued to computer monitors— now that there’s superhuman artificial intelligence capable of distinguishing drones from those other flying objects. Automated watchfulness, thanks to machine learning, has given police and other agencies tasked with maintaining security an important countermeasure to help them keep pace with swarms of new drones taking to the skies. Autors: Jeremy Hsu; Appeared in: IEEE Spectrum Publication date: Jul 2017, volume: 54, issue:7, pages: 10 - 11 Publisher: IEEE
» AID: A Benchmark Data Set for Performance Evaluation of Aerial Scene Classification
 Abstract:Aerial scene classification, which aims to automatically label an aerial image with a specific semantic category, is a fundamental problem for understanding high-resolution remote sensing imagery. In recent years, it has become an active task in the remote sensing area, and numerous algorithms have been proposed for this task, including many machine learning and data-driven approaches. However, the existing data sets for aerial scene classification, such as UC-Merced data set and WHU-RS19, contain relatively small sizes, and the results on them are already saturated. This largely limits the development of scene classification algorithms. This paper describes the Aerial Image data set (AID): a large-scale data set for aerial scene classification. The goal of AID is to advance the state of the arts in scene classification of remote sensing images. For creating AID, we collect and annotate more than 10000 aerial scene images. In addition, a comprehensive review of the existing aerial scene classification techniques as well as recent widely used deep learning methods is given. Finally, we provide a performance analysis of typical aerial scene classification and deep learning approaches on AID, which can be served as the baseline results on this benchmark. Autors: Gui-Song Xia;Jingwen Hu;Fan Hu;Baoguang Shi;Xiang Bai;Yanfei Zhong;Liangpei Zhang;Xiaoqiang Lu; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Jul 2017, volume: 55, issue:7, pages: 3965 - 3981 Publisher: IEEE
» Air-Filled Long Slot Leaky-Wave Antenna Based on Folded Half-Mode Waveguide Using Silicon Bulk Micromachining Technology for Millimeter-Wave Band
 Abstract:An air-filled long slot leaky-wave antenna (LWA) based on folded half-mode waveguide (FHMW) fabricated using silicon substrate is proposed for millimeter-wave application. As is well known, the high-permittivity silicon dielectric is not suitable for antenna design. Thanks to the through-wafer dry etching and gold-plating processes deriving from the silicon bulk micromachining technology, three purely air-filled structures including the vertical part of the FHMW that also acts as the leaky-wave long slot in the top layer, horizontal part of the FHMW and matching section in the middle layer, and coupling slot in the bottom layer constitute the high-performance air-filled long slot LWA. To the best of the authors’ knowledge, this is the first time that an FHMW is adopted for antenna design. Compared with the conventional half-mode waveguide, the profile is lowered, the required silicon layer number is fixed to three, and the design can be more flexible. Experiment of the fabricated prototype shows that the main beam can be scanned from 41° to 49° with a gain variation between 13.15 and 15.41 dBi in the frequency range from 56 to 64 GHz. Moreover, confirmation of the design strategy provides the feasibility to realize the system-in-package solution. Autors: Le Chang;Zhijun Zhang;Yue Li;Shaodong Wang;Zhenghe Feng; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3409 - 3418 Publisher: IEEE
» Air-to-Dielectric-Filled Two-Hole Substrate-Integrated Waveguide Directional Coupler
 Abstract:A two-hole directional coupler consisting of an air-filled substrate-integrated waveguide (AFSIW) coupled to a dielectric-filled substrate-integrated waveguide (SIW) is introduced and studied for the first time. The design of the proposed two-hole coupler, based on different dielectric-loaded SIWs and on multilayer printed circuit board process, is presented in detail with its theoretical foundation. The proposed coupler is of interest for monitoring high-performance, self-packaged, and low-cost millimeter-wave substrate integrated systems based on AFSIW. For demonstration purposes, a forward coupler operating in the Ka-band satellite uplink frequency band (27 to 31 GHz) has been designed and fabricated. In its frequency range of operation, it achieves measured insertion loss, coupling, and isolation of 0.28 ± 0.15 dB, 20.8 ± 0.24 dB, and 46.76 ± 3.92 dB, respectively. Autors: Frédéric Parment;Anthony Ghiotto;Tan-Phu Vuong;Jean-Marc Duchamp;Ke Wu; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Jul 2017, volume: 27, issue:7, pages: 621 - 623 Publisher: IEEE
» Algorithmic Principles of Remote PPG
 Abstract:This paper introduces a mathematical model that incorporates the pertinent optical and physiological properties of skin reflections with the objective to increase our understanding of the algorithmic principles behind remote photoplethysmography (rPPG). The model is used to explain the different choices that were made in existing rPPG methods for pulse extraction. The understanding that comes from the model can be used to design robust or application-specific rPPG solutions. We illustrate this by designing an alternative rPPG method, where a projection plane orthogonal to the skin tone is used for pulse extraction. A large benchmark on the various discussed rPPG methods shows that their relative merits can indeed be understood from the proposed model. Autors: Wenjin Wang;Albertus C. den Brinker;Sander Stuijk;Gerard de Haan; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Jul 2017, volume: 64, issue:7, pages: 1479 - 1491 Publisher: IEEE
» Alternative LP and SOCP Hierarchies for ACOPF Problems
 Abstract:The alternating current optimal power flow (ACOPF) problem optimizes the generation and the distribution of electric energy taking into account the active and the reactive power generation limits, demand requirements, bus voltage limits, and network flow limits. The ACOPF problem can be formulated as a nonconvex polynomial program that is generally difficult to solve due to the nonlinear power flow constraints. A recently proposed approach to globally solve the ACOPF problem is through the formulation of a hierarchy of semidefinite programs that are computationally challenging to solve for large-scale problems. In this paper, we explore a solution approach that alleviates this computational burden by using hierarchies of linear and second order cone programs and by exploiting the network structure of the transmission grid. Furthermore, we show that the first level of the second order cone hierarchy is equivalent to solving the conic dual of the approximation that was recently proposed in the literature, which provides the optimal solution of the ACOPF problem for special network topologies. Autors: Xiaolong Kuang;Bissan Ghaddar;Joe Naoum-Sawaya;Luis F. Zuluaga; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2828 - 2836 Publisher: IEEE
» Aluminum-Doped Zinc Oxide Transparent Electrode Prepared by Atomic Layer Deposition for Organic Light Emitting Devices
 Abstract:Transparent conductive aluminum-doped zinc oxide (AZO) films are being introduced as alternatives to indium tin oxide (ITO) films, because they do not contain indium, which is expensive and toxic. In this study, the structural, electrical, and optical properties of AZO electrodes fabricated by atomic layer deposition (ALD) at a low temperature of 150 °C were examined by X-ray photoemission spectroscopy and scanning electron microscopy. The H2O purge time was changed in the ZnO cycle to alter the orientation of crystal phases and the film's electrical conductivity. An optimized AZO electrode, which had an Al:Zn mole ratio of 1:49, was prepared with a 20 s H2 O purge time. The resulting transparent electrode had a low resistivity (1.25 mΩ·cm ± 0.2 mΩ·cm) and a high transmittance (83.2% at 550 nm). The AZO film exhibited a high work function of 4.7 eV. Consequently, an classic organic light-emitting device (OLED) with an N,N′-bis-(1naphthl)-diphenyl-1,1′ -diphenyl-4,4′ -diamine and tris(8-quinolinolato) aluminum structure was fabricated on a glass substrate using the optimized AZO anode, and a maximum current efficiency of 3.9 cd/A was achieved. These results suggest that this method for preparing transparent conductive films via ALD can be used to create anodes for OLEDs. Autors: Hui Liu;Yun-Fei Liu;Peng-Peng Xiong;Ping Chen;Hui-Ying Li;Jing-Wen Hou;Bo-Nan Kang;Yu Duan; Appeared in: IEEE Transactions on Nanotechnology Publication date: Jul 2017, volume: 16, issue:4, pages: 634 - 638 Publisher: IEEE
» Amplified Spontaneous Emission and Rayleigh Scattering in Few-Mode Fiber Raman Amplifiers
 Abstract:A theoretical model of noise—amplified spontaneous emission and Rayleigh backscattering—in few-mode fiber Raman amplifiers is presented in this letter. Based on this model, the equalization of the signal modal gain determines the equalization of the noise modal gain. The model can also be used to predict the mode-dependent optical signal-noise ratio. The theoretical results of this model are consistent with reported experimental results. Autors: Wei Wang;Jian Zhao;Zhiqun Yang;Chao Li;Zhen Wang;Liyao Yu;Ruilong Mi; Appeared in: IEEE Photonics Technology Letters Publication date: Jul 2017, volume: 29, issue:14, pages: 1159 - 1162 Publisher: IEEE
» An 802.11a/b/g/n/ac WLAN Transceiver for $2 \times 2$ MIMO and Simultaneous Dual-Band Operation With +29 dBm $\text{P}_{\mathrm {sat}}$ Integrated Power Amplifiers
 Abstract:This paper describes the first dual-band MIMO 802.11a/b/g/n/ac WLAN RF transceiver capable of simultaneous dual-band operation. The measured receiver sensitivity of 2 GHz at 54 Mbps is −78.3 dBm and of 5 GHz for VHT80 is −66 dBm. The 802.11ac MIMO 20-MHz MCS0 2 and 5 GHz receiver sensitivity levels are −96 and −95.5 dBm, respectively. Integrated power amplifiers with of +29 dBm enable the 2-GHz transmitters to achieve TX output power of +23.5 dBm at 54-Mbps 64-quadratic-amplitude modulation (QAM). The 5-GHz transmitters achieve +17 dBm output for VHT80 256-QAM. This WLAN-BT connectivity system-on-chip is implemented in 40-nm CMOS technology. Autors: Shing Tak Yan;Lu Ye;Raghavendra Kulkarni;Edward Myers;Hsieh-Chih Shih;Hongbing Wu;Shadi Saberi;Darshan Kadia;Dicle Ozis;Lei Zhou;Eric Middleton;Joo Leong Tham; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Jul 2017, volume: 52, issue:7, pages: 1798 - 1813 Publisher: IEEE
» An LC Decoupling Network for Two Antennas Working at Low Frequencies
 Abstract:This paper presents an LC low-pass network to decouple a pair of coupled antennas working at low frequencies. Comparing with existing decoupling techniques, the proposed decoupling network provides a wideband but compact decoupling solution. Moreover, a generalized one-fit-all scheme is justified to implement the decoupling network with an antenna independent core network. By adjusting a few external components, the same core network can be applied to a collection of antenna pairs with different coupling levels and antenna form factors. Four design examples are given to demonstrate the unique features of the proposed network for low-frequency applications. In all cases, the decoupling network significantly improves the isolation between two antennas over a wide frequency band while the intrinsic matching bandwidth of the antennas is maintained. Autors: Huan Meng;Ke-Li Wu; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Jul 2017, volume: 65, issue:7, pages: 2321 - 2329 Publisher: IEEE
» An Accurate Field Model Requiring Minimal Map Data for Guiding and Diffusion in Streets and Buildings
 Abstract:Theory of normal mode propagation in a line-of-sight street scenario is extended to include propagation into buildings through coupling to a diffuse indoor field. Signal strength predictions are in close agreement with measurements, producing 2 dB and ≤ 3.5 dB root-mean-square model-data difference, in line-of-sight and outdoor-indoor scenarios, respectively. The full 3-D field model predicts actual signal directions and antenna correlations as a function of range, important for evaluating performance of directional antennas and spatial diversity. Only minimal description of the environment is needed, i.e., street width and representative building wall properties, without any interior details. Autors: Dmitry Chizhik;Mauricio Rodríguez;Rodolfo Feick;Reinaldo A. Valenzuela; Appeared in: IEEE Transactions on Wireless Communications Publication date: Jul 2017, volume: 16, issue:7, pages: 4537 - 4546 Publisher: IEEE
» An Accurate Subcircuit Model of SiC Half-Bridge Module for Switching-Loss Optimization
 Abstract:The increasing demand for high power density requires the power converter to operate in high switching frequency. Silicon carbide (SiC) power module is regarded as one of the most promising candidates for high-frequency applications due to the superior switching speed and low switching loss. With the increase of switching frequency, the switching loss will be the limiting factor of efficiency. Hence, it should be minimized during each switching transition. The optimization of switching loss is normally achieved by the repetitive double pulse test experiments. It is time-consuming to find an optimum gate resistance to achieve the tradeoff between switching loss and electromagnetic interface. In this paper, an accurate subcircuit model for SiC power module is proposed to assist optimization of switching loss in converter design. By considering the device physics and structure, an accurate Miller capacitance model is obtained. Moreover, a parameter extraction procedure is presented, which is based on the datasheet. Good agreements are achieved between the PSpice simulation and experiment. Autors: Shan Yin;Pengfei Tu;Peng Wang;King Jet Tseng;Chen Qi;Xiaolei Hu;Michael Zagrodnik;Rejeki Simanjorang; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3840 - 3848 Publisher: IEEE
» An Adaptive Multilook Approach for Small Sets of Multitemporal SAR Data Based on Adaptive Joint Data Vector
 Abstract:The multitemporal interferometric synthetic aperture radar (InSAR) technique is a potential tool for measuring digital elevation models and surface deformation. It has the advantage of high precision, competitive spatial resolution, and wide coverage. To improve the accuracy of the final results, some adaptive multilook strategies have been proposed in which the identification of statistically homogeneous pixels (SHPs) is the key task. However, these methods are not always reliable in the case of small data sets. To improve this reliability, SHPs are identified based on the adaptive joint data vector comprising of temporal sample and spatial information in this letter. Additionally, the formulation of adaptive joint data vector is combined with local spatial features of SAR images. The presented adaptive multilook approach can be used in many interferometric applications, such as InSAR data filtering and coherence estimation. Experiments on six TerraSAR-X stripmap images of Tianjin in China validate the feasibility and effectiveness of the proposed approach. Autors: Huina Song;Yingfei Sun;Robert Wang;Ning Li;Bowen Zhang;Yingjie Wang;Wenbo Fei; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Jul 2017, volume: 14, issue:7, pages: 1161 - 1165 Publisher: IEEE
» An Adaptive QR Decomposition Processor for Carrier-Aggregated LTE-A in 28-nm FD-SOI
 Abstract:This paper presents an adaptive QR decomposition (QRD) processor for five-band carrier-aggregated Long Term Evolution-Advanced downlinks. The design uses time and frequency correlation properties of wireless channels to reduce QRD computations while maintaining an uncoded bit error rate loss below 1 dB. An analysis on the performance of a linear interpolating QRD is presented, and optimum distances for different channel conditions are suggested. The Householder transform suited for spatially correlated scenarios is chosen and modified for concurrent vector rotations resulting in high throughput. Based on these, a parallel hardware architecture suitable for easy reconfigurability and low power is developed and fabricated in 28-nm fully depleted silicon-on-insulator technology. The QRD unit occupies 205k gates of logic and has a maximum throughput of 22 MQRD/s while consuming 29 mW of power. On a circuit level, the back gate feature is leveraged to double operational frequency in low time-frequency correlation channels or to lower power consumption to 1.9 mW in favorable conditions. The proposed system provides designers with multiple levels of adaptive control from architectural to circuit level for power-performance tradeoffs and is well suited for mobile devices operating on limited battery energy. Autors: Rakesh Gangarajaiah;Ove Edfors;Liang Liu; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Jul 2017, volume: 64, issue:7, pages: 1914 - 1926 Publisher: IEEE
» An Advanced Impedance Calibration Method for Nanoscale Microwave Imaging at Broad Frequency Range
 Abstract:A new calibration method for nanoscale complex impedance imaging with the scanning microwave microscope is presented, which allows to calibrate the complete frequency range in a short automated procedure. The vector network analyzer and the corresponding electronically switched calibration capabilities in combination with time domain gating and microwave network modeling are used to de-embed the full system. The entire calibration requires not more than 5 min and the acquisition of one single electrostatic force microscopy approach curve. In order to demonstrate the broadband capabilities, calibrated approach curves at various frequencies are presented. Nano-Schottky diodes on a semiconductor substrate as well as biological cells were measured to demonstrate that the sample conductance and susceptance are in agreement with the theoretical expectations for the samples. This advanced workflow of quantitative impedance calibration may have many applications in the fields of semiconductor failure analysis, 2-D materials, and biological samples in their native liquid environment. Autors: Manuel Kasper;Georg Gramse;Ferry Kienberger; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Jul 2017, volume: 65, issue:7, pages: 2418 - 2424 Publisher: IEEE
» An Algorithm to Identify Surface Snowfall From GPM DPR Observations
 Abstract:The Dual-Frequency Precipitation Radar (DPR) on board the Global Precipitation Measurement (GPM) core satellite has reflectivity measurements at two different frequency bands, namely, Ku- and Ka-bands. The dual-frequency ratio from these measurements has been used to perform rain-type classification and microphysics retrieval in the current DPR level 2 algorithm. In this paper, a surface snowfall identification algorithm is developed using GPM DPR observations. This algorithm provides a new approach to detect snowfall through radar observations, such as measured dual-frequency ratio. This algorithm is developed using GPM DPR data as well as Atmospheric Radiation Measurement (ARM) X/Ka-band radar data during the snowfall experiment. Several snow events observed by both DPR and ground radars are used in the algorithm validation, showing good comparisons. Autors: Minda Le;V. Chandrasekar;Sounak Biswas; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Jul 2017, volume: 55, issue:7, pages: 4059 - 4071 Publisher: IEEE
» An All-Digital Fully Integrated Inductive Buck Regulator With A 250-MHz Multi-Sampled Compensator and a Lightweight Auto-Tuner in 130-nm CMOS
 Abstract:A 125-MHz fully integrated inductive buck voltage regulator using 11.6-nH wirebond inductance and 3.2-nF on-chip capacitance is presented in 130-nm CMOS. An all-digital architecture is presented to ease integration in digital process nodes. The IVR demonstrates enhanced bandwidth enabled by a multi-sampled digital compensator with reduced precision computation. A fast and lightweight auto-tuning engine is presented to optimize steady-state stability and transient response under variation in passives. A resistive transient assist scheme and an adaptive all-digital discontinuous conduction mode control are presented to reduce transient response time and enhance light-load efficiency, respectively. The 130-nm testchip demonstrates a peak efficiency of 71% and a 2.9-V/ output slew during large reference transient. Autors: Monodeep Kar;Arvind Singh;Anand Rajan;Vivek De;Saibal Mukhopadhyay; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Jul 2017, volume: 52, issue:7, pages: 1825 - 1835 Publisher: IEEE
» An Alternate Circuit for Narrow-Bandpass Elliptic Microstrip Filter Design
 Abstract:This letter demonstrates the dual transmission zeros (TZs) of bandpass elliptic prototype filters that can be directly implemented with two resonators in microstrip. An experimental filter based on the proposed alternate circuits is designed and fabricated. In order to improve the rejection of stopband, two additional TZs are introduced to the proposed filter. By means of directly implementing an elliptic bandpass filter in microstrip, the insertion loss of the presented filter can be less than 0.8 dB, and the result is better than 0.583, which means the proposed filter has a good selectivity. Autors: Sen Chen;Ling-Feng Shi;Gong-Xu Liu;Jian-Hui Xun; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Jul 2017, volume: 27, issue:7, pages: 624 - 626 Publisher: IEEE
» An Anisotropic Diffusion-Based Dynamic Combined Energy Model for Seismic Denoising
 Abstract:In this letter, we combine anisotropic and isotropic diffusion models and establish a combined energy variational model for seismic denoising. We propose a dynamic threshold to separate seismic sections into different feature areas and to choose different diffusion methods more precisely according to the characteristics of the seismic sections. Multilevel noise and multilevel edges can be treated automatically. Denoised results from a synthetic model and from field seismic sections demonstrate that our proposed model can suppress random noise and preserve the features of seismic sections efficiently. Autors: Hui Chen;Jun Feng;Bin Zhou;Ying Hu;Ke Guo; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Jul 2017, volume: 14, issue:7, pages: 1061 - 1065 Publisher: IEEE
» An ANN-GA Semantic Rule-Based System to Reduce the Gap Between Predicted and Actual Energy Consumption in Buildings
 Abstract:This paper addresses the endemic problem of the gap between predicted and actual energy performance in public buildings. A system engineering approach is used to characterize energy performance factoring in building intrinsic properties, occupancy patterns, environmental conditions, as well as available control variables and their respective ranges. Due to the lack of historical data, a theoretical simulation model is considered. A semantic mapping process is proposed using principle component analysis (PCA) and multi regression analysis (MRA) to determine the governing (i.e., most sensitive) variables to reduce the energy gap with a (near) real-time capability. Further, an artificial neural network (ANN) is developed to learn the patterns of this semantic mapping, and is used as the cost function of a genetic algorithm (GA)-based optimization tool to generate optimized energy saving rules factoring in multiple objectives and constraints. Finally, a novel rule evaluation process is developed to evaluate the generated energy saving rules, their boundaries, and underpinning variables. The proposed solution has been tested on both a simulation platform and a pilot building – a care home in the Netherlands. Validation results suggest an average 25% energy reduction while meeting occupants’ comfort conditions. Autors: Baris Yuce;Yacine Rezgui; Appeared in: IEEE Transactions on Automation Science and Engineering Publication date: Jul 2017, volume: 14, issue:3, pages: 1351 - 1363 Publisher: IEEE
» An Automatic Equalizer Based on Forward–Flyback Converter for Series-Connected Battery Strings
 Abstract:This paper proposes an automatic any-cells-to-any-cells battery equalizer, which merges the forward and flyback converters through a common multiwinding transformer. The windings of the transformer are divided into two groups, which have opposite polarities. The principles of the proposed equalizer are that the equalization in one group is achieved based on forward conversion and the balancing between the two different groups is based on flyback conversion, by which the magnetic energy stored in the transformer can be automatically reset without using additional demagnetizing circuits. Moreover, only one MOSFET and one primary winding are required for each cell, resulting in smaller size and lower cost. One pair of complementary control signals is employed for all MOSFETs, and energy can be automatically and directly delivered from any high-voltage cells to any low-voltage cells without the requirement of cell monitoring circuits, thereby leading to a high balancing efficiency and speed. The proposed topology can achieve the global equalization for a long battery string through connecting the secondary sides of transformers without the need of additional components for the equalization among modules, which also overcomes the mismatching problem of multiple windings. The validity of the proposed equalizer is verified through experiments, and the balancing efficiency can reach up to 89.4% over a wide range of conditions. Autors: Yunlong Shang;Bing Xia;Chenghui Zhang;Naxin Cui;Jufeng Yang;Chunting Chris Mi; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5380 - 5391 Publisher: IEEE
» An Early Preamble Collision Detection Scheme Based on Tagged Preambles for Cellular M2M Random Access
 Abstract:In this paper, we propose an early preamble collision detection (e-PACD) scheme at the first step of random access (RA) procedure based on tagged preambles (PAs), which consist of both PA and tag Zadoff–Chu sequences using different root numbers, respectively. The proposed e-PACD scheme enables faster PA collision detection and notification, compared with the conventional RA scheme. Accordingly, it can reduce the RA delay and remove resource wastes which occur at the third step of the conventional RA procedure. The reduced RA delay achieved by the proposed e-PACD scheme can contribute to an ultralow latency requirement in fifth-generation (5G) cellular networks. In addition, the proposed e-PACD scheme enables the eNodeB to monitor the number of RA-attempting nodes (RA load) on each physical RA channel slot. The PACD probability and the RA load monitoring accuracy are mathematically analyzed, and the RA performance enhancement of the proposed scheme is evaluated in terms of RA success probability, average RA delay, and RA resource efficiency, compared with the conventional RA scheme. Autors: Han Seung Jang;Su Min Kim;Hong-Shik Park;Dan Keun Sung; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Jul 2017, volume: 66, issue:7, pages: 5974 - 5984 Publisher: IEEE
» An Early Stage Interturn Fault Diagnosis of PMSMs by Using Negative-Sequence Components
 Abstract:This paper proposes an early stage interturn short-circuit fault (ISCF) diagnosis method for permanent magnet synchronous machines. A fault indicator is suggested based on a new theoretical analysis of the relationship between the fault current and the rotor speed. The fault indicator is shown to be robust to the rotor speed changes in slight ISCFs. It is calculated by introducing negative-sequence components (NSCs). It is shown that the fault indicator using NSCs can diagnose slighter ISCFs than that using zero-sequence components. Experimental results demonstrate the effectiveness of the proposed method for diagnosing early stage ISCFs with a small number of short-circuited turns and low fault current. Autors: Hyeyun Jeong;Seokbae Moon;Sang Woo Kim; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5701 - 5708 Publisher: IEEE
» An ECC-Assisted Postpackage Repair Methodology in Main Memory Systems
 Abstract:As dynamic random access memories (DRAMs) operate in the field, hard errors resulting from wearout occur. Unless corrected or repaired, hard errors halt normal operations, degrading the performance of a system and causing the replacement of memory modules. To improve performance and availability of memory modules, error-correcting codes (ECCs) are employed in a memory system. However, since recent field studies on DRAM errors have shown that a correctable error is highly likely to result in another error with the same address and in the same column or row, incorporating ECCs for mitigating not only soft errors but also hard errors in field operations is insufficient for ensuring reliable field operations. We propose a methodology that detects and repairs aging errors in DRAMs while operating in the field. We propose a methodology that reconfigures the remaining redundant resources after manufacturing-level repair into postpackage redundant resources. We also propose an ECC-assisted postpackage repair (PPR) flow that detects an error, identifies the type and location of the error, and invokes PPR for aging errors without built-in self-test/repair circuits. Employing a 2-GB ECC–dual in-line memory module of data-rate type three synchronous dynamic random access memories as a case study, we demonstrate that our PPR scheme improves the lifetime of DRAMs. Autors: Dae-Hyun Kim;Linda Milor; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Jul 2017, volume: 25, issue:7, pages: 2045 - 2058 Publisher: IEEE
» An Efficient and Easy-to-Implement Tag Identification Algorithm for UHF RFID Systems
 Abstract:In this letter, a novel sub-frame-based dynamic frame slotted ALOHA (DFSA) algorithm is proposed for efficient tag identification based on EPC C1 Gen2 radio frequency identification (RFID) standard. Through the observation of slot states in a sub-frame, the reader estimates the tag number, and quickly adjusts the frame length to match the quantity of backlog. Once the appropriate frame length is observed, the algorithm will return to traditional DSFA. We use the modified maximum a posteriori probability (MAP) method for the estimation of tag quantity to improve the accuracy. To reduce the computation complexity of traditional MAP, we use tables to store estimation numbers. Due to the length strict of sub-frames, only a relatively small size of memory is required. Simulation results show that dynamic sub-frame MAP can improve the system utility (approximately 0.36) and reduce the computation complexity, only with an addition of less than 3-kB memory. Autors: Yongrui Chen;Jian Su;Weidong Yi; Appeared in: IEEE Communications Letters Publication date: Jul 2017, volume: 21, issue:7, pages: 1509 - 1512 Publisher: IEEE
» An Efficient and Stabilizing Model Predictive Control of Switched Systems
 Abstract:Model Predictive Control (MPC) of switched systems typically requires an on-line solution of a Mixed Integer Program (MIP). Since the worst case complexity of the optimization problem increases exponentially with respect to the number of integer variables, an on-line implementation of the MPC for problems with large number of sub-systems and/or large horizons is usually expensive. In this technical note, we propose a stabilizing MPC formulation for state-dependent switched systems, that enables a tradeoff between the computational complexity of the MPC controller and the optimal performance of the closed-loop system. The proposed approach uses a pre-terminal set, in addition to the positively invariant terminal set, which aids in reducing the on-line complexity although at the expense of optimality. Examples are presented to illustrate the computational benefits of the proposed MPC strategy over existing MPC for switched systems. Autors: K. Hariprasad;Sharad Bhartiya; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3401 - 3407 Publisher: IEEE
» An Efficient Globally Optimal Algorithm for Asymmetric Point Matching
 Abstract:Although the robust point matching algorithm has been demonstrated to be effective for non-rigid registration, there are several issues with the adopted deterministic annealing optimization technique. First, it is not globally optimal and regularization on the spatial transformation is needed for good matching results. Second, it tends to align the mass centers of two point sets. To address these issues, we propose a globally optimal algorithm for the robust point matching problem in the case that each model point has a counterpart in scene set. By eliminating the transformation variables, we show that the original matching problem is reduced to a concave quadratic assignment problem where the objective function has a low rank Hessian matrix. This facilitates the use of large scale global optimization techniques. We propose a modified normal rectangular branch-and-bound algorithm to solve the resulting problem where multiple rectangles are simultaneously subdivided to increase the chance of shrinking the rectangle containing the global optimal solution. In addition, we present an efficient lower bounding scheme which has a linear assignment formulation and can be efficiently solved. Extensive experiments on synthetic and real datasets demonstrate the proposed algorithm performs favorably against the state-of-the-art methods in terms of robustness to outliers, matching accuracy, and run-time. Autors: Wei Lian;Lei Zhang;Ming-Hsuan Yang; Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence Publication date: Jul 2017, volume: 39, issue:7, pages: 1281 - 1293 Publisher: IEEE
» An Efficient Optimal Control Method for Open-Loop Transient Stability Emergency Control
 Abstract:With the expansion of modern power systems, the stability issues become more and more prominent. Transient stability emergency control is usually designed in open-loop schemes and applies proper actions to avoid system collapse when transient stability cannot be guaranteed in serious contingencies. Taking transient stability and economic efficiency of power system into consideration, the emergency control problem can be modeled as an optimal control problem, which is computational expensive. In this paper, an optimal control method with constraint aggregation is proposed to reduce computational complexity. The yield nonlinear problem is a fairly small-scale optimization problem which can be efficiently solved by predictor–corrector interior point method. The adjoint sensitivity analysis (ASA) is employed to evaluate the first-order derivative while Broyden–Fletcher–Goldfarb–Shanno (BFGS) algorithm is used to obtain the second-order derivative. Besides, very dishonest Newton (VDHN) method and reusage of LU factorization results are explored to accelerate the forward and backward integration phase of ASA, respectively. The proposed approach is tested on four cases with different scales, and shows its potential in computational efficiency. Autors: Zhihao Li;Guoqiang Yao;Guangchao Geng;Quanyuan Jiang; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2704 - 2713 Publisher: IEEE
» An Efficient Tri-Level Optimization Model for Electric Grid Defense Planning
 Abstract:The work reported in this paper aims at developing a practical and efficient tool for utility transmission planners to protect critical transmission assets from potential physical attacks. A trilevel min–max–min optimization model is proposed to represent actions of a planner, an attacker, and an operator. These three agents share a common objective function, which is the system load shedding. The strong duality theorem is used to merge the middle- and lower-level problems into a single-level one. The resulting mixed-integer bilevel model is solved by a Benders decomposition technique using primal cuts. Two case studies are presented as applications of this novel technique. Additionally, the proposed technique is compared with an implicit enumeration algorithm. Autors: Xuan Wu;Antonio J. Conejo; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2984 - 2994 Publisher: IEEE
» An EH0-Mode Microstrip Leaky-Wave Antenna With Periodical Loading of Shorting Pins
 Abstract:In this paper, a novel class of microstrip leaky-wave antennas (MLWAs) under the operation of the fundamental EH0-mode in a microstrip line (MSL) is presented. The leaky-wave radiation is realized by periodically loading a set of shorting pins in the central plane along the longitudinal direction. Due to the inductive effect of these shorting pins, the phase constant of this pin-loaded MSL is reduced below its free-space counterpart so as to create a fast-wave frequency region for leaky-wave propagation and radiation. Compared with its counterpart higher order EH1- or EH2-mode MLWAs, the strip width of this EH0-mode MLWA can be freely designed with unspecified or narrow strip width. Our extensive investigations are then carried out to demonstrate its inductive-loaded fast-wave mechanism and distinctive characteristics, such as narrower strip width, low cutoff frequency, wide single-mode band, and controllable leakage constant in the fast-wave region. In final, two antenna prototypes with strip widths of 4.0 and 7.5 mm are designed, fabricated, and measured, with simulated and measured results in good agreement, validating the proposed pin-loaded technique for designs of EH0-mode MLWAs. Autors: Danpeng Xie;Lei Zhu;Xiao Zhang; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3419 - 3426 Publisher: IEEE
» An Electrochemistry Study of Cryoelectrolysis in Frozen Physiological Saline
 Abstract:Cryoelectrolysis is a new minimally invasive tissue ablation surgical technique that combines the processes of electrolysis and solid/liquid phase transformation (freezing). This study investigated this new technique by measuring the pH front propagation and the changes in resistance in a tissue simulant made of physiological saline gel with a pH dye as a function of the sample temperature in the high subzero range above the eutectic. Results demonstrated that effective electrolysis can occur in a high subzero freezing milieu and that the propagation of the pH front is only weakly dependent on temperature. These observations are consistent with a mechanism involving ionic movement through the concentrated saline solution channels between ice crystals at subfreezing temperatures above the eutectic. Moreover, results suggest that Joule heating in these microchannels may cause local microscopic melting, the observed weak dependence of pH front propagation on temperature, and the large changes in resistance with time. A final insight provided by the results is that the pH front propagation from the anode is more rapid than from the cathode, a feature indicative of the electro-osmotic flow from the cathode to the anode. The findings in this paper may be critical for designing future cryoelectrolytic ablation surgery protocols. Autors: Thomas J. Manuel;Pujita Munnangi;Boris Rubinsky; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Jul 2017, volume: 64, issue:7, pages: 1654 - 1659 Publisher: IEEE
» An End-to-End Implanted Brain–Machine Interface Antenna System Performance Characterizations and Development
 Abstract:Brain-machine interface (BMI) is a multidisciplinary field that has been recently developed in an attempt to help restore functionalities for paralyzed individuals. One of the key components for the implementation of a wireless BMI necessitates unique designs for both the internal brain and external head antennas. In this paper, we initially revisited the design of an optimized 1-mm3 implantable antenna transferring power and data with a reduced size low profile external reader antenna by utilizing radio-frequency identification (RFID)-inspired backscattering. Detailed computational assessments and specific absorption rate evaluations are performed. Prototypes were characterized in terms of link efficiency through a realized RFID link with up to −25 dB link efficiency. The noise analysis for antennas in biological systems was performed using two novel absorption-noise models. And finally a channel capacity estimation was performed, proving that the BMI antenna link could support up to 100 recording channels. An end-to-end BMI antenna system characterization is detailed in this paper for multichannel implanted neural recording applications. Autors: Lingnan Song;Yahya Rahmat-Samii; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3399 - 3408 Publisher: IEEE
» An Energy-Efficient Hybrid SAR-VCO $\Delta \Sigma$ Capacitance-to-Digital Converter in 40-nm CMOS
 Abstract:This paper presents a highly digital, 0-1 MASH capacitance-to-digital converter (CDC). The CDC works by sampling a reference voltage on the sensing capacitor and then quantizing the charge stored in it by a 9-bit successive approximation register analog-to-digital converter. The residue is fed to a ring voltage-controlled oscillator (VCO) and quantized in time domain. The outputs from the two stages are combined to produce a quantized output with the first-order noise shaping. The proposed two-stage architecture reduces the impact of the VCO’s nonlinearity. A digital calibration technique is used to track the VCO’s gain across process, voltage, and temperature. The absence of any operational amplifier and low oversampling ratio for the VCO results in high energy efficiency. A prototype CDC in a 40-nm CMOS process achieves a 64.2-dB SNR while operating from a 1-V supply and using a sampling frequency of 3 MHz. The prototype achieves a CDC figure of merit of 55 fJ/conversion-step. Autors: Arindam Sanyal;Nan Sun; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Jul 2017, volume: 52, issue:7, pages: 1966 - 1976 Publisher: IEEE
» An Energy-Scalable Accelerator for Blind Image Deblurring
 Abstract:Camera shake is a common cause of blur in cell-phone camera images. Removing blur requires deconvolving the blurred image with a kernel, which is typically unknown and needs to be estimated from the blurred image. This kernel estimation is computationally intensive and takes several minutes on a CPU, which makes it unsuitable for mobile devices. This paper presents the first hardware accelerator for kernel estimation for image deblurring applications. Our approach, using a multi-resolution iteratively reweighted least squares deconvolution engine with DFT-based matrix multiplication, a high-throughput image correlator, and a high-speed selective update-based gradient projection solver, achieves a 78x reduction in kernel estimation runtime, and a 56x reduction in total deblurring time for a image, enabling quick feedback to the user. Configurability in kernel size and number of iterations gives up to ten times energy scalability, allowing the system to trade off runtime with image quality. The test chip, fabricated in TSMC 40-nm CMOS technology, consumes 105 mJ for kernel estimation running at 83 MHz and 0.9 V, making it suitable for integration into mobile devices. Autors: Priyanka Raina;Mehul Tikekar;Anantha P. Chandrakasan; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Jul 2017, volume: 52, issue:7, pages: 1849 - 1862 Publisher: IEEE
» An Enhanced Viola-Jones Vehicle Detection Method From Unmanned Aerial Vehicles Imagery
 Abstract:This research develops an advanced vehicle detection method, which improves the original Viola-Jones (V-J) object detection scheme for better vehicle detections from low-altitude unmanned aerial vehicle (UAV) imagery. The original V-J method is sensitive to objects’ in-plane rotation, and therefore has difficulties in detecting vehicles with unknown orientations in UAV images. To address this issue, this research proposes a road orientation adjustment method, which rotates each UAV image once so that the roads and on-road vehicles on rotated images will be aligned with the horizontal direction and the V-J vehicle detector. Then, the original V-J can be directly applied to achieve better efficiency and accuracy. The enhanced V-J method is further applied for vehicle tracking. Testing results show that both vehicle detection and tracking methods are competitive compared with other existing methods. Future research will focus on expanding the current methods to detect other transport modes, such as buses, trucks, motorcycles, bicycles, and pedestrians. Autors: Yongzheng Xu;Guizhen Yu;Xinkai Wu;Yunpeng Wang;Yalong Ma; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Jul 2017, volume: 18, issue:7, pages: 1845 - 1856 Publisher: IEEE
» An Entropy-Based Analysis of GPR Data for the Assessment of Railway Ballast Conditions
 Abstract:The effective monitoring of ballasted railway track beds is fundamental for maintaining safe operational conditions of railways and lowering maintenance costs. Railway ballast can be damaged over time by the breakdown of aggregates or by the upward migration of fine clay particles from the foundation, along with capillary water. This may cause critical track settlements. To that effect, early stage detection of fouling is of paramount importance. Within this context, ground penetrating radar (GPR) is a rapid nondestructive testing technique, which is being increasingly used for the assessment and health monitoring of railway track substructures. In this paper, we propose a novel and efficient signal processing approach based on entropy analysis, which was applied to GPR data for the assessment of the railway ballast conditions and the detection of fouling. In order to recreate a real-life scenario within the context of railway structures, four different ballast/pollutant mixes were introduced, ranging from clean to highly fouled ballast. GPR systems equipped with two different antennas, ground-coupled (600 and 1600 MHz) and air-coupled (1000 and 2000 MHz), were used for testing purposes. The proposed methodology aims at rapidly identifying distinctive areas of interest related to fouling, thereby lowering significantly the amount of data to be processed and the time required for specialist data processing. Prominent information on the use of suitable frequencies of investigation from the investigated set, as well as the relevant probability values of detection and false alarm, is provided. Autors: Francesco Benedetto;Fabio Tosti;Amir M. Alani; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Jul 2017, volume: 55, issue:7, pages: 3900 - 3908 Publisher: IEEE
» An Equivalent Simulation Method for Pulse Radar Measurement in Anechoic Chamber
 Abstract:When a pulse radar signal is implemented in a range-limited anechoic chamber for radar measurement, the transmitted and reflected signal will be coupled at the receiver. To solve this problem and equivalently simulate the whole process of pulse radar measurement in an anechoic chamber, the interrupted transmitting and receiving method is proposed in this letter based on interrupted sampling. The constraints of the transmitting and receiving parameters are deduced with the sizes of the anechoic chamber and target. The pulse compression of the proposed method is performed. Then, the window function is applied to extract the main peaks after pulse compression. Both the simulation and experimental results are provided to demonstrate the effectiveness of the proposed method in overcoming the coupling between the transmitted and reflected pulse signals. Autors: Xiaobin Liu;Jin Liu;Feng Zhao;Xiaofeng Ai;Guoyu Wang; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Jul 2017, volume: 14, issue:7, pages: 1081 - 1085 Publisher: IEEE
» An Extension of the InSAR-Based Probability Integral Method and Its Application for Predicting 3-D Mining-Induced Displacements Under Different Extraction Conditions
 Abstract:Underground extraction can be roughly classified into three types, i.e., subcritical, critical, and supercritical extraction, in accordance with the geological conditions in the overburden and the geometry of mined-out areas. In 2016, we proposed an approach based on the interferometric synthetic aperture radar (InSAR) technique and the probability integral method (PIM) for the cost-effective prediction of 3-D mining-induced displacements (abbreviated as InSAR-PIM). Due to the inherent assumption of critical extraction in the PIM, the InSAR-PIM method performs well in predicting the 3-D displacements caused by critical and/or supercritical extraction, but poorly for subcritical extraction. In this paper, we first propose a generalized PIM (GPIM) by modifying the traditional PIM with a simplified Boltzmann function. We then replace the PIM of the InSAR-PIM with the proposed GPIM to develop an extension of InSAR-PIM (referred as to InSAR-GPIM). The InSAR-GPIM was tested in the Qianyingzi coal mining area, China. The results show that the InSAR-GPIM-predicted horizontal and vertical displacements caused by subcritical, critical, and supercritical extraction agree well with the in situ observations, with average root-mean-square errors of about 0.032 and 0.050 m, respectively. These accuracies represent improvements of 60.9% and 59% when compared with the accuracies predicted by the InSAR-PIM in the horizontal and vertical directions. The results indicate that the InSAR-GPIM is capable of accurately predicting 3-D mining-induced displacements under different extraction conditions (i.e., subcritical, critical, and supercritical extraction), and it performs much better than the InSAR-PIM in the case of subcritical extraction. It is therefore believed that InSAR-GPIM will have a wider scope of applications than the previous InSAR-PIM. Autors: Ze Fa Yang;Zhi Wei Li;Jian Jun Zhu;Axel Preusse;Hui Wei Yi;Yun Jia Wang;Markus Papst; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Jul 2017, volume: 55, issue:7, pages: 3835 - 3845 Publisher: IEEE
» An Improved Describing Function With Applications for OTA-Based Circuits
 Abstract:Electronic systems make extensive use of operational transconductance amplifiers (OTAs) to build filters and oscillators. Studying the effects of the saturation nonlinearity on these OTA-based circuits is difficult and often requires lengthy simulations to check the system’s performance under large-signal operation. The describing function (DF) theory allows to circumvent these simulations by deriving a signal-dependent linearized gain, which predicts the effects of the nonlinearity. However, its use is limited since the state-of-the-art DFs deviate significantly from the real saturating behavior of OTAs. This paper proposes an improved DF, which can be directly derived from the static nonlinear characteristic of the transconductance amplifier. The performance of the proposed methodology is demonstrated for both an OTA-based filter and oscillator. It is shown that the proposed DF has a better nonlinear prediction capability than the state-of-the-art solutions. Autors: Dries Peumans;Gerd Vandersteen; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Jul 2017, volume: 64, issue:7, pages: 1748 - 1757 Publisher: IEEE
» An Improved IRA Algorithm and Its Application in Critical Eigenvalues Searching for Low Frequency Oscillation Analysis
 Abstract:On the basis of implicitly restarted Arnoldi (IRA) method, an improved algorithm is proposed, in which the dimension of Krylov subspace is dynamically increased to compute eigenvalues in specified circle. First, the radius of searching circles is dynamically expanded through automatically increasing the number of eigenvalues and the dimension of Krylov subspace, based on the locking mechanism. Second, the region where the low frequency oscillation modes located is divided into small independent computing units, which are covered by specified searching circles. Third, the independent computing units can be calculated simultaneously with no effects on each other. The proposed method can avoid eigenvalues missing caused by inappropriate resetting of search number in equidistant-searching IRA method. Furthermore, no manual intervention is needed in the proposed method. Two systems with 570 and 5272 state variables are tested in this paper, and the results indicate that the proposed method is efficient, reliable, and practical. Autors: Chongru Liu;Xiao Li;Pengfei Tian;Mu Wang; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2974 - 2983 Publisher: IEEE
» An Improved Model for Quasi-Ballistic Transport in MOSFETs
 Abstract:We have already presented a compact model for FETs operating in the quasi-ballistic regime [1]. However, this model suffers from two important problems: 1) the profile for charge density along the channel is not correctly accounted for and 2) current is not conserved throughout the channel. In this brief, we propose improvement, which does away with these inaccuracies. Autors: Avirup Dasgupta;Amit Agarwal;Yogesh Singh Chauhan; Appeared in: IEEE Transactions on Electron Devices Publication date: Jul 2017, volume: 64, issue:7, pages: 3032 - 3036 Publisher: IEEE
» An Impulsive Delay Inequality Involving Unbounded Time-Varying Delay and Applications
 Abstract:In this paper, a new impulsive delay inequality that involves unbounded and nondifferentiable time-varying delay is presented. As an application, some sufficient conditions ensuring stability and stabilization of impulsive systems with unbounded time-varying delay are derived. Some numerical examples are given to illustrate the results. Especially, a stabilizing memoryless controller for a second-order time-varying system with unbounded time-varying delay is proposed. Autors: Xiaodi Li;Jinde Cao; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3618 - 3625 Publisher: IEEE
» An Incremental Framework for Video-Based Traffic Sign Detection, Tracking, and Recognition
 Abstract:Video-based traffic sign detection, tracking, and recognition is one of the important components for the intelligent transport systems. Extensive research has shown that pretty good performance can be obtained on public data sets by various state-of-the-art approaches, especially the deep learning methods. However, deep learning methods require extensive computing resources. In addition, these approaches mostly concentrate on single image detection and recognition task, which is not applicable in real-world applications. Different from previous research, we introduce a unified incremental computational framework for traffic sign detection, tracking, and recognition task using the mono-camera mounted on a moving vehicle under non-stationary environments. The main contributions of this paper are threefold: 1) to enhance detection performance by utilizing the contextual information, this paper innovatively utilizes the spatial distribution prior of the traffic signs; 2) to improve the tracking performance and localization accuracy under non-stationary environments, a new efficient incremental framework containing off-line detector, online detector, and motion model predictor together is designed for traffic sign detection and tracking simultaneously; and 3) to get a more stable classification output, a scale-based intra-frame fusion method is proposed. We evaluate our method on two public data sets and the performance has shown that the proposed system can obtain results comparable with the deep learning method with less computing resource in a near-real-time manner. Autors: Yuan Yuan;Zhitong Xiong;Qi Wang; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Jul 2017, volume: 18, issue:7, pages: 1918 - 1929 Publisher: IEEE
» An Integrated Approach for Power System Restoration Planning
 Abstract:Power system outages/blackouts, especially weather related, are becoming more and more frequent, incurring significant economic and social costs. The ability to restore power services quickly after a blackout is crucial for power system resilience. Power system restoration is an extremely complicated process, involving multiple steps, highly combinatorial operational decisions, and highly nonlinear technical constraints, which make restoration planning an exceptionally challenging task. This paper will first introduce the restoration process and operations, examine important issues in restoration, and survey the state of the art in the research and practice of power system restoration planning. Then, we will focus on the commonly used buildup restoration planning strategy, in which the system is sectionalized into smaller subsystems with initial power sources, and then the subsystems are restored in parallel. Due to the complexity, existing approaches treat the sectionalization and restoration separately, leading to a suboptimal restoration plan. We will introduce an integrated restoration planning approach to improve the quality of restoration plans globally (such as shorter overall restoration time) by using mathematical programming and simulation in an interactive and iterative way. Case studies will be provided to illustrate the effectiveness of the proposed approach. Autors: Feng Qiu;Peijie Li; Appeared in: Proceedings of the IEEE Publication date: Jul 2017, volume: 105, issue:7, pages: 1234 - 1252 Publisher: IEEE
» An Iterative Method for Determining the Most Probable Bifurcation in Large Scale Power Systems
 Abstract:An iterative method is presented to determine the most probable voltage stability limit by identifying the closest saddle node bifurcation in a probability-loading space starting at the expected initial system state. The iterative method is applied to the probability space to identify the closest saddle node bifurcation by means of the Mahalanobis distance. Further the method provides an ellipsoidal load subspace corresponding to the most probable bifurcation. This ellipsoid is a lower bound for the probability of bifurcation. To verify the proposed methodology examples are given and the minimum Mahalanobis distance, for dependent and independent load patterns, is compared with the minimum Euclidian distance. Autors: Moritz Mittelstaedt;Sascha Bauer;Armin Schnettler; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2966 - 2973 Publisher: IEEE
» An On-line Sensor Selection Algorithm for SPRT With Multiple Sensors
 Abstract:We present an on-line sensor selection strategy (SSS) for the Sequential Probability Ratio Test (SPRT) with multiple sensors. Each sensor incurs an associated observation cost. We aim to design an SSS, in which the sensor selection may depend causally on the measurement values, that minimizes the expected total observation cost. In general, the optimal SSS can be obtained by solving a dynamic program; however, the problem is computationally quite demanding. We propose a computationally efficient algorithm in which we partition the state space into three regions and solve for the SSS in each region. The computational complexity of the proposed algorithm is linear in the number of sensors and numerical results show that it can well approximate the optimal SSS. Autors: Cheng-Zong Bai;Vijay Gupta; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3532 - 3539 Publisher: IEEE
» An Operational State Aggregation Technique for Transmission Expansion Planning Based on Line Benefits
 Abstract:This paper provides a novel technique to represent in a reduced, or compact, way temporal variability in transmission expansion planning (TEP). This reduction is handled by means of “snapshot selection.” Instead of taking into account all the possible operational states and their associated optimal power flow, a reduced group of them is selected that is representative of all the states that should have an influence on investment decisions. Considering this reduced group of operational states should lead to the same investment decisions as if all the snapshots in the target year were considered. Original operational states are compared in the space of the benefits produced by potential reinforcements considered, which are relevant drivers for investment decisions. The benefits produced by these potential reinforcements are computed based on the incremental change in operation costs resulting from their installation. A clustering algorithm is used to group together those operational states where similar line benefits are realized. Our algorithm has been tested on a modified version of the standard IEEE 24 bus system. The method produces promising results and proves to be more efficient than other snapshot selection methods used until now in computing an accurate enough selection of snapshots representing system operation variability in TEP. Autors: Quentin Ploussard;Luis Olmos;Andrés Ramos; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 2744 - 2755 Publisher: IEEE

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