#### Electrical and Electronics Engineering publications abstract of: 07-2017 sorted by title, page: 3

» 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
» An Optical MEMS Accelerometer Based on a Two-Dimensional Photonic Crystal Add-Drop Filter
 Abstract:In this paper, a novel optical microelectromechanical systems accelerometer sensor is proposed by using a two-dimensional photonic crystal add-drop filter which is relied on a wavelength modulation approach. The proposed optical sensing system consists of a laser diode light source, tunable add-drop filter based on ring resonator principal, photo-detector, and integrated waveguides. Simulation results show that the functional characteristics of the proposed sensor are as follows: mechanical sensitivity of 1.6 nm/g, linear measurement range of 156 to 156 g, optical sensitivity of 0.0756 nm/g, and first resonance frequency of 12.9 kHz. These functional characteristics make it very interesting in a wide spectrum of applications, ranging from consumer electronics to automotive and inertial navigation. Autors: Arash Sheikhaleh;Kambiz Abedi;Kian Jafari; Appeared in: Journal of Lightwave Technology Publication date: Jul 2017, volume: 35, issue:14, pages: 3029 - 3034 Publisher: IEEE
» An Output-Current-Dependent DC-Link Energy Regulation Scheme for a Family of Soft-Switched AC/DC Offline LED Drivers Without Electrolytic Capacitors
 Abstract:In order to provide a constant current to the Light-emitting diodes (LEDs) and to minimize the size and cost of the driver circuit in ac/dc offline LED drivers, electrolytic capacitors are conventionally used due to their high energy density and low cost. However, electrolytic capacitors are sensitive to operating temperature and have much shorter lifetime than the LED semiconductor devices. This paper proposes an improved control scheme that is capable to control the output LED current and regulate the dc-link capacitor's energy simultaneously for a family of single-stage soft-switched high power factor LED driver topologies. Each of these topologies consists of an integrated power factor correction (PFC) circuit. Due to the proposed controller's capability to control the LED current directly via variable frequency control and the dc-link capacitor's voltage via duty ratio control, the required energy storage capacitance can be significantly reduced, thereby allowing small size film capacitor to be used as the energy storage capacitor. Simulation results are provided on two different LED driver topologies, one with an integrated boost PFC stage and the other one with an integrated buck–boost PFC stage, to verify the performance of the proposed control scheme. Experimental results are also been provided on a 12-W prototype to highlight the merits of this paper. Autors: John Lam;Nader El-Taweel;Mehdi Abbasi; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5838 - 5850 Publisher: IEEE
» An Overview of Remote Isolation Systems Applied in Process Industries
 Abstract:This paper describes the application of remote isolation applied in mining industry conveyance systems. Remote isolation removes personnel from potentially dangerous electrical lockout tasks by removing the element of human error. Safe verified isolation of electrical systems has proved to increase production output by reducing the required time to electrically isolate industrial systems where zero energy is required prior to performing work. Time saved to both isolate and de-isolate is converted to production time and increased manufacturing throughput. This paper describes the application of remote isolation systems, discusses implementation of enhanced safety systems and the necessary engagement with local regulating authorities. Finally, a case study of an actual installation discusses specific details where these systems have been installed. Autors: David B. Durocher;Mike Lane; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 4136 - 4141 Publisher: IEEE
» An RF-Powered DLL-Based 2.4-GHz Transmitter for Autonomous Wireless Sensor Nodes
 Abstract:This paper presents the system and circuit design of a compact radio frequency (RF)-powered 2.4-GHz CMOS transmitter (TX) to be used for autonomous wireless sensor nodes (WSNs). The proposed TX utilizes the received dedicated RF signal for both energy harvesting as well as frequency synthesis. A TX RF carrier is derived from the received RF signal by means of a delay locked loop and XOR-based frequency multiplier. The 50- load is subsequently driven by a tuned switching RF power amplifier (PA) with 25% duty cycle input for high global efficiency. The design is fabricated in 40-nm CMOS technology and occupies a die area of 0.16 mm2. Experimental results show a rectifier with 36.83% peak efficiency and power management circuit with 120-nA current consumption that enables a low start-up power of −18.4 dBm. The TX outputs a continuous 2.44-GHz RF signal at −2.57 dBm with 36.5% PA drain efficiency and 23.9% global efficiency from a 915-MHz RF input and supports ON–OFF keying modulation. Autors: Mark Stoopman;Kathleen Philips;Wouter A. Serdijn; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Jul 2017, volume: 65, issue:7, pages: 2399 - 2408 Publisher: IEEE
» An Ultralow-Power Wake-Up Receiver Based on Direct Active RF Detection
 Abstract:An ultralow-power direct active RF detection wake-up receiver (WuRx) is presented. In order to reduce the power consumption and system complexity, a differential RF envelope detector is implemented in a complementary current-reuse architecture. The detector sensitivity is enhanced through an embedded matching network with signal passive amplification. A prototype receiver is fabricated in 0.18- CMOS technology with a core size of 0.46 mm2. At the operating frequency of 2.4 GHz, the receiver achieves a −50 dBm sensitivity [10−3 bit error rate (BER)] at a data rate of 200 kbps while consuming from a 0.8 V supply voltage. The WuRx is capable of achieving a 10−3 BER for 200 kb/s data rate with a signal to interference ratio greater than −30 dB at ±10 MHz offset. Autors: Kuang-Wei Cheng;Shih-En Chen; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Jul 2017, volume: 64, issue:7, pages: 1661 - 1672 Publisher: IEEE
» Analog Transmission of Correlated Sources Over Fading SIMO Multiple Access Channels
 Abstract:Joint source-channel coding for discrete-time analog sources is an appealing transmission approach because of its extremely low delay and complexity. When the users access the channel orthogonally, analog transmission of correlated information over fading multiple access channels (MACs) using modulo-like mappings provides better performance than uncoded transmission. In this paper, we propose a simplified decoder for modulo mappings in possibly non-orthogonal MAC scenarios with a single-antenna users and a multiple-antenna receiver. Sphere decoding is investigated to reduce the computational complexity when the number of users is large. In addition, affordable strategies are proposed to optimize the mapping parameters according to the channel conditions and the source correlation. The obtained results show that the use of modulo mappings is suitable when the number of antennas at the receiver is larger than the number of users and for high correlation between user data. Autors: Pedro Suárez-Casal;Óscar Fresnedo;Luis Castedo;Javier García-Frías; Appeared in: IEEE Transactions on Communications Publication date: Jul 2017, volume: 65, issue:7, pages: 2999 - 3011 Publisher: IEEE
» Analyses and Experiments of the Schottky Contact Super Barrier Rectifier (SSBR)
 Abstract:In this letter, the electrical characteristics of the Schottky contact super barrier rectifier (SSBR) are explained and verified by simulations and experiments. In addition to an MOS channel operating as a super barrier, there is an indirect Schottky contact in the SSBR for electrons. Adjusting both the Schottky contact for coarse adjustment and the super barrier for fine adjustment can improve the tradeoff between the forward voltages and reverse leakage currents. The SSBR exhibits similar Schottky-like electrical characteristics to those of the SBR with ohmic contact presented earlier, except that there is no conductivity modulation for the SSBR, and it still operates in unipolar conducting mode at forward voltages above the p-n junction knee voltage. The measured breakdown voltage of SSBR is 56 V, and the reverse recovery time is approximately30 ns. Autors: Wensuo Chen;Ruijin Liao;Zheng Zeng;Peijian Zhang;Yi Zhong;Kaizhou Tan;Hao Chen;Bo Zhang; Appeared in: IEEE Electron Device Letters Publication date: Jul 2017, volume: 38, issue:7, pages: 902 - 905 Publisher: IEEE
» Analysis and Damping of Mechanical Resonance of Wind Power Generators Contributing to Frequency Regulation
 Abstract:Wind power generators will become increasingly useful in modern power systems; therefore, they should be able to support the system frequency in a way similar to that of conventional generators. Droop and virtual inertia are the most reported methods in the literature. However, their impact on the generator and system frequency stability, when the double-mass mechanical dynamics of a wind power generator are considered, has not been addressed thoroughly. In this paper, small-signal modeling, analysis, and eigenvalues studies are used to show that incorporating a wind power generator in the frequency regulation can expose its shaft to forces stimulating its natural resonance frequency dynamics and lead to instability. This paper shows that the mechanical resonance of frequency-regulating wind generators must be studied and enhanced not individually but as a part of the whole power system stability analyses. To overcome the stability problem caused by implementing frequency regulation in wind generators, this paper investigates different alternatives to stabilize the generator dynamics and, at the same time, minimize undesirable interference in the conventional wind power generator controllers. Time-domain simulation results validate the analytical results and discussions. Autors: Mohammadreza Fakhari Moghaddam Arani;Yasser Abdel-Rady I. Mohamed; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 3195 - 3204 Publisher: IEEE
» Analysis and Design of a Single-Stage Isolated AC–DC LED Driver With a Voltage Doubler Rectifier
 Abstract:In order to reduce the cost and volume of small-medium power ac–dc light-emitting diode (LED) lighting systems, single-stage LED drivers are often used to drive LEDs with constant current. In this paper, a single-stage isolated high-power factor ac–dc LED driver is proposed and analyzed in detail, which is composed of a buck–boost power factor correction unit operating in discontinuous conduction mode and an isolated dc/dc unit with a voltage doubler rectifier, and the two units are integrated together by sharing the same power switch. Very high input power factor is achieved since the PFC unit operates with almost fixed duty ratio during half period of the utility line voltage. Since a voltage doubler rectifier is included in the isolated dc/dc unit, magnetic core size of the transformer and voltage stress of the secondary side diodes are reduced remarkably. First, the operating principle and performance of the LED driver are analyzed. Then, the main parameters are quantitatively calculated out in detail. Finally, a comparative analysis is presented and a 120 W experimental prototype with 1 A output current is built according to the calculated parameters and the experimental results are presented to verify the correctness of the theoretical analysis and parameter design. Autors: Quanming Luo;Jian Huang;Qingqing He;Kun Ma;Luowei Zhou; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5807 - 5817 Publisher: IEEE
» Analysis and Design of Adaptive OCDMA Passive Optical Networks
 Abstract:Optical code division multiple access (OCDMA) systems can support multiple classes of service by differentiating code parameters, power level, and diversity order. In this paper, we analyze bit error rate (BER) performance of a multiclass 1-D/2-D OCDMA system and propose a new approximation method that can be used to generate accurate estimation of system BER using a simple mathematical form. The proposed approximation provides insight into proper system level analysis, system level design and sensitivity of system performance to the factors such as code parameters, power level, and diversity order. Considering code design, code cardinality, and system performance constraints, two design problems are defined and their optimal solutions are provided. We, then, propose an adaptive OCDMA passive optical networks (OCDMA-PON) that adaptively shares unused resources of inactive users among active ones to improve upstream system performance. Using the approximated BER expression and defined design problems, two adaptive code allocation algorithms for the adaptive OCDMA-PON are presented and their performances are evaluated by simulation. Simulation results show that the adaptive code allocation algorithms can increase average transmission rate or decrease average transmitted optical power of optical network units for dynamic traffic patterns. According to the simulation results, for an adaptive OCDMA-PON with BER value of 10-7 and user activity probability of 0.5, transmission rate (transmitted optical power) can be increased (decreased) by a factor of 2.53 (0.25) compared to fixed code assignment. Autors: Mohammad Hadi;Mohammad Reza Pakravan; Appeared in: Journal of Lightwave Technology Publication date: Jul 2017, volume: 35, issue:14, pages: 2853 - 2863 Publisher: IEEE
» Analysis and Design of Current-Fed Half-Bridge (C)(LC)–( LC) Resonant Topology for Inductive Wireless Power Transfer Application
 Abstract:This paper proposes and analyzes a new power electronics circuit topology for wireless inductive power transfer application using current-fed half-bridge converter with CCL-LC resonant network. The major focus is analysis and implementation of a new current-fed resonant topology with current-sharing and voltage doubling features. Generally, inductive power transfer circuits with current fed converter use parallel CL resonant tank to transfer power effectively through air gap. However, in medium power application, this topology suffers from a major limitation of high voltage stress across the inverter semiconductor devices owing to high reactive power consumed by loosely coupled coil. In proposed topology, this is mitigated by adding a capacitor in series with the coil developing series-parallel CCL tank. The power flow is controlled through variable frequency modulation. Soft-switching of the devices is obtained irrespective of the load current. For grid-to-vehicle or solar-to-vehicle, the converter is analyzed and detailed design procedure is illustrated. Experimental results are presented to verify the analysis and demonstrate the performance. Autors: Suvendu Samanta;Akshay Kumar Rathore;Duleepa J. Thrimawithana; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3917 - 3926 Publisher: IEEE
» Analysis and Suppression of Zero Sequence Circulating Current in Open Winding PMSM Drives With Common DC Bus
 Abstract:In this paper, the zero sequence circulating current in open winding permanent magnet synchronous machine (OW-PMSM) drives with common dc bus is systematically analyzed for the first time. It is revealed that the zero sequence circulating current is affected by zero sequence back-electromotive force, cross coupling voltages in zero sequence from the machine side, pulse-width modulation induced zero sequence voltage, and inverter nonlinearity from the inverter side. Particularly, the influences from the cross coupling voltages in zero sequence and parasitic effect of inverter nonlinearity are investigated for the first time in this paper. Then, the synthetic model of the equivalent zero sequence circuit is proposed as well. Each cause is studied independently via analytical modeling, finite element analysis, and experiments. Meanwhile, to tackle this issue, the relevant suppression strategy using frequency adaptive proportional resonant controller is presented and tested on the 3 kW OW-PMSM platform. Autors: Hanlin Zhan;Zi-qiang Zhu;Milijana Odavic; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3609 - 3620 Publisher: IEEE
» Analysis of 220-GHz Low-Loss Quasi-Elliptic Waveguide Bandpass Filter
 Abstract:A 220-GHz low-loss and wideband waveguide bandpass filter with fourth-order quasi-elliptic response is presented and analyzed in this letter. An electric cross-coupling realized by easily manufactured capacitive iris is introduced in the classical folded quadruplet topology. The prototype fabricated by conventional computer numerical control (CNC)-metal-milling technology exhibits meaningful results of an insertion loss of around 0.6 dB and a 3-dB fractional bandwidth of 9.8% centered at 214.3 GHz, which are in excellent agreement with the simulated ones. The effects of tolerance and surface roughness on the filter performance are discussed in detail. All the results indicate that the present CNC process can meet the accuracy and roughness requirement of such waveguide filter in WR-4 band. Autors: Jiang-Qiao Ding;Sheng-Cai Shi;Kang Zhou;Dong Liu;Wen Wu; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Jul 2017, volume: 27, issue:7, pages: 648 - 650 Publisher: IEEE
» Analysis of Clockwise and Counter-Clockwise Hysteresis Characteristics in 3-D NAND Flash Memory Cells
 Abstract:The origin of two different hysteresis pheno- mena observed in a few cells of 3-D NAND flash memory with a tube-type poly-Si body was analyzed. To identify the origin, we analyzed the capture and emission property of charges in two different trap sites by measuring devices at various temperature conditions and using fast I–V measurement. It was found that the clockwise hysteresis property is originated from the traps in the tunneling oxide butted to tube-type poly-Si body and the counter-clockwise hysteresis property is originated from the traps in the high- blocking dielectric. Although the number of abnormal cells with a large hysteresis is much smaller than that of the normal cells, it is confirmed by pulse measurement that these abnormal cells can produce large threshold voltage variations. Autors: Ho-Jung Kang;Nagyong Choi;Jong-Ho Bae;Byung-Gook Park;Jong-Ho Lee; Appeared in: IEEE Electron Device Letters Publication date: Jul 2017, volume: 38, issue:7, pages: 867 - 870 Publisher: IEEE
» Analysis of D2D Underlaid Cellular Networks: SIR Meta Distribution and Mean Local Delay
 Abstract:We study the performance of device-to-device (D2D) communication underlaying cellular wireless network in terms of the meta distribution of the signal-to-interference ratio (SIR), which is the distribution of the conditional SIR distribution given the locations of the wireless nodes. Modeling D2D transmitters and base stations as Poisson point processes (PPPs), moments of the conditional SIR distribution are derived in order to calculate analytical expressions for the meta distribution and the mean local delay of the typical D2D receiver and cellular downlink user. It turns out that for D2D users, the total interference from the D2D interferers and base stations is equal in distribution to that of a single PPP, while for downlink users, the effect of the interference from the D2D network is more complicated. We also derive the region of transmit probabilities for the D2D users and base stations that result in a finite mean local delay and give a simple inner bound on that region. Finally, the impact of increasing the base station density on the mean local delay, the meta distribution, and the density of users reliably served is investigated with numerical results. Autors: Mohammad Salehi;Abbas Mohammadi;Martin Haenggi; Appeared in: IEEE Transactions on Communications Publication date: Jul 2017, volume: 65, issue:7, pages: 2904 - 2916 Publisher: IEEE
» Analysis of Evolving Oil Spills in Full-Polarimetric and Hybrid-Polarity SAR
 Abstract:Oil spill detection using a time series of images acquired off Norway in June 2015 with the uninhabited aerial vehicle synthetic aperture radar is examined. The relative performance of a set of features derived from quad-polarization versus hybrid-polarity (HP) modes in detection of various types of slicks as they evolve on a high wind driven sea surface is evaluated. It is shown that the HP mode is comparable with the full-polarimetric mode in its ability to distinguish the various slicks from open water (OW) for challenging conditions of high winds (9–12 m/s), small release volumes (0.2–0.5 m3), and during the period 0–9 h following release. The features that contain the cross-polarization component are better for distinguishing the various slicks from open water at later and more developed stages. Although these features are not available in the HP mode, we identify alternative features to achieve similar results. In addition, a clear correlation between the results of individual features and their dependence on particular components within the two-scale Bragg scattering theory is identified. The features that show poor detectability of the oil slicks are those that are independent of the small-scale roughness, while the features resulting in good separability were dependent on several factors in the two-scale Bragg scattering model. We conclude that the HP mode is a viable alternative for SAR-based oil spill detection and monitoring that provides comparable results to those from the quad-polarimetric SAR. Autors: Martine M. Espeseth;Stine Skrunes;Cathleen E. Jones;Camilla Brekke;Benjamin Holt;Anthony P. Doulgeris; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Jul 2017, volume: 55, issue:7, pages: 4190 - 4210 Publisher: IEEE
» Analysis of GaN HEMTs Switching Transients Using Compact Model
 Abstract:This paper presents a methodology to model GaN power HEMT switching transients. Thus, a compact model to predict devices’ pulse switching characteristics and current collapse reliability issue has been developed. Parasitic RC subcircuits and a standard double-pulse switching tester to model intrinsic parasitic effects and to analyze power dissipation of GaN power HEMT are proposed and presented. Switching transient including gate-lag and drain-lag is predicted for ideal (without trap) and nonideal (with trap) devices. The results are validated by and compared to 2-D finite-element technology computer-aided design simulations. The original aim of this exercise is to develop a fast (near-real-time) model which can predict dynamic behavior of single and multiple power GaN HEMTs used for the switching transients of GaN power devices at circuit level. Autors: Soroush Faramehr;Petar Igić; Appeared in: IEEE Transactions on Electron Devices Publication date: Jul 2017, volume: 64, issue:7, pages: 2900 - 2905 Publisher: IEEE
» Analysis of Handover Failures in Heterogeneous Networks With Fading
 Abstract:The handover process is one of the most critical functions in a cellular network and is in charge of maintaining seamless connectivity of user equipments across multiple cells. The handover process is driven by signal measurements from the neighboring base stations (BSs), and it is adversely affected by the time and frequency selectivity of the radio propagation channel. In this paper, we introduce a new model for analyzing handover performance in heterogeneous networks (HetNets) as a function of vehicular user velocity, cell size, and mobility management parameters. In order to investigate the impact of shadowing and fading on handover performance, we extract relevant statistics obtained from a Third-Generation Partnership Project (3GPP)-compliant HetNet simulator, and subsequently, we integrate these statistics into our analytical model to analyze both handover failure and ping-pong probabilities under fluctuating channel conditions. Computer simulations validate the analytical findings, which show that fading can significantly degrade the handover performance in HetNets with vehicular users. Autors: Karthik Vasudeva;Meryem Simsek;David López-Pérez;İsmail Güvenç; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Jul 2017, volume: 66, issue:7, pages: 6060 - 6074 Publisher: IEEE
» Analysis of Space Charge Distribution in dc Corona Discharge Field Computed With Finite-Element Method
 Abstract:Method of the dc corona field calculation is proposed. Suitable boundary conditions of the discharge electrode are investigated. Computations based upon the finite-element method are performed using commercial programs. A new mathematical expression, which meets Kaptzov’s assumption, is introduced to describe the electric charge distribution near the surface of the corona electrode. Application of the COMSOL, which enables us to use the iterative procedure merged with MATLAB capabilities has been used for the modeling. Space charge density distribution in interelectrode space is presented. 2-D numerical model for computation of the direct current corona field in wire-to-plane electrode system is presented. Results have been obtained using mathematical model and compared with experimental ones. Autors: Povilas Marčiulionis; Appeared in: IEEE Transactions on Plasma Science Publication date: Jul 2017, volume: 45, issue:7, pages: 1698 - 1703 Publisher: IEEE
» Analysis of the Short-Term Response in the Drain Current of a-IGZO TFT to Light Pulses
 Abstract:In this letter, the response in the drain current ( of the amorphous indium–gallium–zinc oxide thin-film transistors under positive-bias illumination stress is measured with respect to time in less than 5 s under light pulses with altering frequencies and duty ratios. The curves of under the light pulses are affected by the different defect-reacting rates under illumination and in the dark. By taking the derivative of , the trend of the change in the number of defects becomes clear. The total behavior of in response to light pulses can be fairly predicted by the integral of the derivative terms with a correction factor of charge trapping. Autors: H.-W. Liu;P.-C. Chan;J.-H. Lin;C.-Y. Chang;Y.-H. Tai; Appeared in: IEEE Electron Device Letters Publication date: Jul 2017, volume: 38, issue:7, pages: 887 - 889 Publisher: IEEE
» Analysis of Transient Electromagnetic Scattering From Composite Conducting-Dielectric Targets With the Time-Domain Fast Dipole Method
 Abstract:An efficient time-domain fast dipole method is proposed to accelerate the time-domain volume-surface integral equation for analyzing the transient electromagnetic scattering from composite conducting-dielectric targets with arbitrary shape and inhomogeneity. This scheme is based on the equivalent dipole moment and the Taylor series expansion of the transient far-field. The computational complexity and memory requirement of the proposed algorithm can be reduced considerably by embedding the fast algorithm in a hierarchical framework. Several numerical examples are presented to demonstrate the accuracy and efficiency of the proposed method. Autors: G. S. Cheng;D. Z. Ding;R. S. Chen; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3800 - 3805 Publisher: IEEE
» Analysis of Winding Configurations and Slot-Pole Combinations in Fractional-Slots Resolvers
 Abstract:Resolvers, due to their robust structure, are widely used in automation systems. The need for accurate position estimation beside the precise control of present PM motors, persuade machine designers to select a resolver with high pole numbers. By the aid of concentrated winding topologies high pole numbers is accessible. Among different topologies of concentrated windings fractional slot (FS) type has been focused by a lot of researches. FS concentrated winding (FSCW) offers high pole number under limited slots, identical on tooth coils, short end winding, and compact design. However, depending on the topology, there are major drawbacks, such as magnetic noises, high sub-harmonics, high leakage inductances, high core losses, and low fault-tolerance, resulted from inappropriate slot-pole combinations. So, in this paper after developing FSCW principles for resolvers, different configurations, including slot-pole combinations and winding layers are suggested. Then, 3-D time stepping finite element method is used to introduce five indices for evaluating the perfectness of these combinations and arrangements on the performance of resolvers. Finally, a prototype of 10-pole axial flux resolver has been constructed and tested. Good agreement between experimental and simulation results are obtained. Autors: Ramin Alipour-Sarabi;Zahra Nasiri-Gheidari;Farid Tootoonchian;Hashem Oraee; Appeared in: IEEE Sensors Journal Publication date: Jul 2017, volume: 17, issue:14, pages: 4420 - 4428 Publisher: IEEE
» Analytic Passive Intermodulation Model for Flange Connection Based on Metallic Contact Nonlinearity Approximation
 Abstract:Passive intermodulation (PIM) is one of the major reliability problems in microwave communication systems. In this paper, the PIM interference generated by the metal–insulator–metal (MIM) contact nonlinearity was analytically modeled and experimentally verified. The pressure-dependent nonlinear – equations of the MIM contact were derived based on electrical contact theory and verified using a manufactured MIM contact structure. Then a point source model for the PIM product based on the metallic contact nonlinearity was proposed. The PIM product is mainly determined by the contact resistance, surface current density, and nonlinear current coefficient from the model, and in the small contact resistance region, the PIM level decreasing rates are 60, 60, and 20 dB/decade by decreasing the contact resistance, surface current density, and the nonlinear current coefficient, respectively. A designated PIM current source was utilized to verify the relationship. In the end, the PIM equation for the rectangular waveguide connection was derived based on the point source model. This model will provide guidance on low PIM system design. Autors: Xiaolong Zhao;Yongning He;Ming Ye;Fan Gao;Wenbo Peng;Yun Li;Chunjiang Bai;Wanzhao Cui; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Jul 2017, volume: 65, issue:7, pages: 2279 - 2287 Publisher: IEEE
» Analytical Expression for the Time-Domain Green’s Function of a Discrete Plane Wave Propagating in a 3-D FDTD Grid
 Abstract:In this paper, a closed-form expression for the time-domain dyadic Green’s function of a discrete plane wave (DPW) propagating in a 3-D finite-difference time-domain (FDTD) grid is derived. In order to verify our findings, the time-domain implementation of the DPW-injection technique is developed with the use of the derived expression for 3-D total-field/scattered-field (TFSF) FDTD simulations. This implementation requires computations of the time-domain Green’s function of DPW with the use of multiple-precision arithmetic. Then, excitations at the TFSF interface can be computed as a time-domain convolution of a source function with Green’s function of DPW. The developed time-domain implementation of the DPW-injection technique demonstrates the leakage error across the TFSF interface around the numerical noise level that verifies the correctness of the derivation. Autors: Tomasz P. Stefański;Bartosz Reichel; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3607 - 3614 Publisher: IEEE
» Analytical Model of Correlation Factor for Human-Body Model to Transmission-Line Pulse ESD Testing
 Abstract:Physics of correlation between standard ESD testing and transmission line pulse test results on semiconductor devices using a simple resistor (R) inductor (L) capacitor (C) circuit model approach is presented. The correlation is not a constant factor, however, it can be used to evaluate the time to failure for the device during the human-body model event and is attributed to the time to induce the thermal runaway of the device during the electrostatic-discharge event. Autors: Jian-Hsing Lee;Natarajan Mahadeva Iyer; Appeared in: IEEE Electron Device Letters Publication date: Jul 2017, volume: 38, issue:7, pages: 952 - 954 Publisher: IEEE
» Analytical Modeling of Rough Surface SAR Images Under Small Perturbation Approximation
 Abstract:In high-resolution synthetic aperture radar (SAR) images, the spatial pattern of a homogenous region conveys rich information regarding the specific scatterers being imaged. Analytical modelings of both scattering and imaging processes are critical to better interpret a specific scatterer’s appearances in SAR imagery and thereafter quantitatively retrieve its physical parameters. Small-scale rough surface scattering represents one of the mostly common scattering mechanisms and yet its SAR image characteristics have not been well studied. This becomes more critical in millimeter-wave/terahertz regime as smooth surfaces would become slightly rough under millimeter/submillimeter wavelengths. In this paper, we recast the small perturbation method (SPM) approximation of rough surface scattering under the deterministic finite-length surface condition. By ignoring evanescent waves, a simplified SPM solution for rough facet is derived as well as the analytical form of its SAR image under the conventional setup. Then, we reformulate the scattering imaging process of rough facet as a signal processing chain that further reveals the underlying mechanism of rough surface as imaged by radar. The proposed method is extensively validated against the method of moments in terms of both scattering coefficients and imaging patterns. It is found that under the conventional SPM validity condition, the error of scattering coefficients is less than 1.5 dB, while the correlation between SPM-calculated and MoM-calcualted SAR images is larger than 0.9. The proposed model of rough facet SAR image could serve as the theoretical basis for parameter inversion and surface reconstruction. Preliminary cases of the inversion of rough surface spectrum using both simulated and real SAR image patches are presented. Autors: Feng Xu;Peng Wang; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Jul 2017, volume: 55, issue:7, pages: 3694 - 3707 Publisher: IEEE
» Analyzing Burn Out and Random Trips at Starting: Induction Motors Driving Main Blowers
 Abstract:Two squirrel-cage induction motors rated at 2,984 kW, 6.9 kV, 60 Hz, and 3,556 r/min with a direct start driving a main blower in a blast furnace facility present random trips during starts and also an event of motor burning. These trips interrupt the motor starting by 50 and 46 N function actuations. Considering the risk of motor damage, the consequent interruption of blown air supplied to the furnace, and the risk of human injuries by step or touch voltage, this article presents an analysis of the causes and a proposition for a solution to eliminate these trips. Autors: Leonardo Adolpho Silva;Karina Giancoti;Francisco Amaro;Igor Amariz Pires; Appeared in: IEEE Industry Applications Magazine Publication date: Jul 2017, volume: 23, issue:4, pages: 66 - 75 Publisher: IEEE
» Angle-of-Arrival-Dependent Interference Modeling in Rician Massive MIMO
 Abstract:In this paper, we study the uplink in a single-cell massive multiple-input–multiple-output system. The base station (BS) is equipped with three antenna arrays, each covering one third of the cell area. Each antenna array comprises a large yet finite number of antennas. The single-antenna users are randomly and uniformly distributed in the cell, transmitting to the BS utilizing full channel inversion power control. All users experience Rician fading. Receiver maximum-ratio-combining is performed at the BS. Under such a setting, we focus on one cell sector and analyze the intrasector interference in a realistic situation where the number of BS antennas is not extremely large compared with the user number. In particular, we show that, due to the line-of-sight (LoS) component of the channel, the interference is partially determined by the angles of arrival of the signals. We approximate the LoS component interference by a Beta mixture. The interference in Rician fading is then modeled as a noncentral chi-square distribution with a random noncentrality parameter, corresponding to the LoS component. The approximate interference distribution can be used to compute signal-to-interference-ratio-dependent metrics such as outage probability and average throughput. Autors: Yeqing Hu;Yi Hong;Jamie Evans; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Jul 2017, volume: 66, issue:7, pages: 6171 - 6183 Publisher: IEEE
» Antieavesdropping With Selfish Jamming in Wireless Networks: A Bertrand Game Approach
 Abstract:Wireless communications are vulnerable to eavesdropping attacks due to their broadcast nature. To deal with their emerging challenge of physical layer security, in this paper, we study the antieavesdropping problem in the presence of selfish jammers, who desire to achieve maximum profit for themselves. We consider both the single-channel multijammer (SCMJ) model and the multichannel single-jammer (MCSJ) model. We investigate the interaction between the source that transmits secret information and friendly jammer nodes who assist the source by interfering with the eavesdropper. This problem is formulated as an oligopoly market consisting of a few firms and a buyer. By modeling the problem as a Bertrand game based on price competition, we obtain the optimal pricing scheme for the friendly, while for selfish jammers, the utility of those jammers is maximized. For the SCMJ model, we prove the existence of Bertrand Equilibrium by deriving a closed-form expression for the optimal price strategy. For the MCSJ model, a closed-form expression for power allocation is derived, based on which a new algorithm is designed to obtain the optimal strategy of the jammer. Finally, via simulations, we verify our theoretical analysis. Autors: Kun Wang;Li Yuan;Toshiaki Miyazaki;Song Guo;Yanfei Sun; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Jul 2017, volume: 66, issue:7, pages: 6268 - 6279 Publisher: IEEE
» APPLES: Efficiently Handling Spin-lock Synchronization on Virtualized Platforms
» Application of Adaptive Digital Beamforming to Osaka University Phased Array Weather Radar
 Abstract:The X-band phased array weather radar (PAWR) at Osaka University has a rapid scanning rate and is capable of high-density observations in elevation; it produces approximately 100 plan position indicator radar images with a 60-km range, at different elevation angles, in less than 30 s. The PAWR uses a fan-shaped beam with a narrow beamwidth (1.2°) in azimuth and a wider beamwidth (from 5° to 10°) in elevation. With digital beamforming (DBF), the elevation beamwidth can be reduced to 1.2°, using 128 antenna elements arranged in tandem. Although the fan-shaped beam is useful for rapid scanning, the received signals tend to be affected by ground clutter. In this paper, we investigate the clutter suppression capability of common DBF methods: Fourier, Capon, and minimum mean-square error (MMSE) beamforming. Furthermore, to improve performance when the PAWR data contain errors—such as lacking data caused by mechanical problems—a correction method is proposed. The effect of clutter suppression using MMSE is shown to be greatly improved if used together with the proposed correction method. The resulting method is shown to sufficiently suppress clutter in all elevation angles above a few degrees, even in the presence of strong clutter; its clutter reduction performance is compared and found to be superior to the ones of the analyzed conventional DBF methods. Autors: Hiroshi Kikuchi;Eiichi Yoshikawa;Tomoo Ushio;Fumihiko Mizutani;Masakazu Wada; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Jul 2017, volume: 55, issue:7, pages: 3875 - 3884 Publisher: IEEE
» Application-Based Optimization of Multi-Level Clustering in Ad Hoc and Sensor Networks
 Abstract:Multi-level clustering offers the scalability that is essential to large-scale ad hoc and sensor networks in addition to supporting energy-efficient strategies for gathering data. The optimality of a multi-level network largely depends on two design variables: 1) the number of levels and 2) the number of nodes operating at each level. We characterize these variables within a multi-hop multi-level hierarchical network of variable sizes that gathers and aggregates data at each level. Our network communication cost model (EEHC-VA) is parameterized by the size of the data forwarded at each level. We minimize the communication cost to obtain the optimal probabilities of distributed and independent selection of level-(+1) nodes from level- nodes. Interestingly, we have identified intervals—based on the number of nodes and aggregated data sizes—within which single- or two-level hierarchies are optimal. The results have been numerically verified for a wide range of parameters and validated with network simulations. Finally, the impact of these results on the network architectures is discussed for selected applications and aggregation schemes. Autors: Deepa Phanish;Edward J. Coyle; Appeared in: IEEE Transactions on Wireless Communications Publication date: Jul 2017, volume: 16, issue:7, pages: 4460 - 4475 Publisher: IEEE
» Applying Spatial Orbit Motion to Accelerometer Sensitivity Measurement
 Abstract:For appropriate application of an accelerometer, it is required to measure both its geometric axis of sensitivity and transverse sensitivity. Besides single-axial vibration exciters and planar testing systems, a tri-axial vibration exciter with the ability of generating spatial orbit motion steps in the field of transducer calibration. The method of applying spatial orbit motion to accelerometer sensitivity measurement is investigated. Amplitudes and phases of the acceleration components for a tri-axial vibration exciter to compose a given spatial orbit is derived. The accelerometer output vector of a spatial spherical orbit that is composed of multiple rotated circular orbits is constructed. The over determined rectilinear equations of the accelerometer output vector are formulated to solve the accelerometer’s sensitivity by the least squares approach. The output vectors of the spatial spherical orbit are distributed on a sphere surface and the determined accelerometer sensitivity matches well with the spatial orbit motion and the measured accelerometer outputs. Autors: Zhihua Liu;Chenguang Cai;Mei Yu;Ming Yang; Appeared in: IEEE Sensors Journal Publication date: Jul 2017, volume: 17, issue:14, pages: 4483 - 4491 Publisher: IEEE
» Approximately Optimal Computing Budget Allocation for Selection of the Best and Worst Designs
 Abstract:Ordinal optimization is an efficient technique to choose and rank various engineering designs that require time-consuming discrete-event simulations. Optimal computing budget allocation (OCBA) has been an important tool to enhance its efficiency such that the best design is selected in a timely fashion. It, however, fails to address the issue of selecting the best and worst designs efficiently. The need to select both rapidly given a fixed computing budget has arisen from many applications. This work develops a new OCBA-based approach for selecting both best and worst designs at the same time. Its theoretical foundation is laid. Our numerical results show that it can well outperform all the existing methods in terms of probability of correct selection and computational efficiency. Autors: JunQi Zhang;Liang Zhang;Cheng Wang;MengChu Zhou; Appeared in: IEEE Transactions on Automatic Control Publication date: Jul 2017, volume: 62, issue:7, pages: 3249 - 3261 Publisher: IEEE
» Architecture and Algorithms for Privacy Preserving Thermal Inertial Load Management by a Load Serving Entity
 Abstract:Motivated by the growing importance of demand response in modern power system's operations, we propose an architecture and supporting algorithms for privacy preserving thermal inertial load management as a service provided by the load serving entity (LSE). We focus on an LSE managing a population of its customers’ air conditioners, and propose a contractual model where the LSE guarantees quality of service to each customer in terms of keeping their indoor temperature trajectories within respective bands around the desired individual comfort temperatures. We show how the LSE can price the contracts differentiated by the flexibility embodied by the width of the specified bands. We address architectural questions of (i) how the LSE can strategize its energy procurement based on price and ambient temperature forecasts, (ii) how an LSE can close the real-time control loop at the aggregate level while providing individual comfort guarantees to loads, without ever measuring the states of an air conditioner for privacy reasons. Control algorithms to enable our proposed architecture are given, and their efficacy is demonstrated on real data. Autors: Abhishek Halder;Xinbo Geng;P. R. Kumar;Le Xie; Appeared in: IEEE Transactions on Power Systems Publication date: Jul 2017, volume: 32, issue:4, pages: 3275 - 3286 Publisher: IEEE
» Are You Flexible Enough to Adapt? [From the Editor's Desk]
 Abstract:Presents the introductory editorial for this issue of the publication. Autors: Alfy Riddle; Appeared in: IEEE Microwave Magazine Publication date: Jul 2017, volume: 18, issue:5, pages: 6 - 10 Publisher: IEEE
» Artificial Potential-Based Adaptive ${{H}_{\infty }}$ Synchronized Tracking Control for Accommodation Vessel
 Abstract:Combining with artificial potential field and robust methods, the neural network (NN)-based adaptive synchronized tracking control is proposed for accommodation vessel (AV). The control task is to drive AV synchronous tracking floating production storage and offloading (FPSO). For finishing the task, NN is employed to approximate the unknown nonlinear dynamics of AV; method is to guarantee the system states of AV robust to exogenous disturbances; artificial potential method aims to produce the attractive and repulsive forces to assist AV maintaining desired distance with FPSO so that the gangway connecting both AV and FPSO is operated smoothly. Finally, it is proven that the proposed control scheme can guarantee that all error signals of the tracking control are Semi-Globally Uniformly Ultimately Bounded (SGUUB) and AV can synchronously track FPSO to desired accuracy. The simulation results further demonstrate the effectiveness of the proposed method. Autors: Guoxing Wen;Shuzhi Sam Ge;Fangwen Tu;Yoo Sang Choo; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5640 - 5647 Publisher: IEEE
» Assessing Cement Plant Thermal Performance
 Abstract:Energy consumption is one of the largest cost components in the production of Portland cement. Energy is consumed through the fuel required to make the cement, as well as the electricity consumed to operate the manufacturing equipment. This paper discusses the fuel requirements for producing cement, and demonstrates some simple techniques for assessing and improving thermal performance. The basic heat requirements for driving the chemical processes are the starting point for the assessment. These are found to be rather similar throughout the industry with only minor differences between different facilities. Higher chemical variability increases the heat requirements as more heat is required for the reactions and the reaction temperatures are higher. Thermal efficiency is primarily determined by the thermal recuperation of heat contained in the fuel combustion exhaust gases and the intermediate product, clinker. This heat is recuperated in preheaters and clinker coolers, respectively. The factors that drive efficient heat recuperation are discussed and simple performance assessment indicators provided. Operators who pay close attention to their thermal performance can reduce operating costs and obtain a competitive advantage in the market. Autors: John Kline;Charles Kline; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 4097 - 4108 Publisher: IEEE
» Assessment of High-Frequency Performance Limit of Black Phosphorus Field-Effect Transistors
 Abstract:Recently, gigahertz frequencies have been reported with black phosphorus (BP) field-effect transistors (FETs), yet the high-frequency performance limit has remained unexplored. Here we project the frequency limit of BP FETs based on rigorous atomistic quantum transport simulations and the small-signal circuit model. Our self-consistent nonequilibrium Green’s function (NEGF) simulation results show that semiconducting BP FETs exhibit clear saturation behaviors with the drain voltage, unlike zero-bandgap graphene devices, leading to >10 THz frequencies for both intrinsic cutoff frequency () and unity power gain frequency (). To develop keen insight into practical devices, we discuss the optimization of and by varying various device parameters such as channel length (), oxide thickness, device width, gate resistance, contact resistance, and parasitic capacitance. Although extrinsic and can be significantly affected by the contact resistance and parasitic capacitance, they can remain near THz frequency range ( GHz; THz) through proper engineering, particularly with an aggressive- channel length scaling ( nm). Our benchmark against the experimental data indicates that there still exists large room for optimization in fabrication, suggesting further advancement of high-frequency performance of state-of-the-art BP FETs for the future analog and radio-frequency applications. Autors: Demin Yin;AbdulAziz AlMutairi;Youngki Yoon; Appeared in: IEEE Transactions on Electron Devices Publication date: Jul 2017, volume: 64, issue:7, pages: 2984 - 2991 Publisher: IEEE
» Assessment of Power Swings in Hydropower Plants Through High-Order Modeling and Eigenanalysis
 Abstract:POWER plants are subject to introduce disturbances in the power grid, resulting from interactions with the dynamical behavior of the energy source subsystem. In the case of hydropower plants when used to compensate for variations of power generation and consumption, instabilities or undesirable disturbances may arise. They may be caused by phenomena such as part load vortex rope pulsations in the draft tube of Francis turbines. This may affect the dynamical behavior of the power plant and lead to troublesome interactions with the grid. This paper presents a case study of an existing hydropower plant that illustrates the effects of pressure pulsations due to vortex rope precession on the draft tube of Francis turbines. It also showcases possible solutions to the mitigation of the effects of this disturbing hydraulic phenomenon over the operation of the generators and electrical system. The investigated system is a 1-GW hydropower plant (4 × 250 MW units). The assessment of the power swings is performed through modal analysis combined with frequency-domain and time-domain simulations, which are then compared with onsite measurements. Autors: Pedro C. O. Silva;Christophe Nicolet;Patrick Grillot;Jean-Louis Drommi;Basile Kawkabani; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 3345 - 3354 Publisher: IEEE
» Assessment of Terra MODIS On-Orbit Polarization Sensitivity Using Pseudoinvariant Desert Sites
 Abstract:The Moderate Resolution Imaging Spectroradiometer (MODIS) is currently flying on NASA’s Earth Observing System Terra and Aqua satellites, launched in 1999 and 2002, respectively. MODIS reflective solar bands in the visible wavelength range are known to be sensitive to polarized light based on prelaunch polarization sensitivity tests. After about five years of on-orbit operations, it was discovered that the polarization sensitivity at short wavelengths had shown a noticeable increase. In this paper, we examine the impact of polarization on measured top-of-atmosphere (TOA) reflectances based on MODIS Collection-6 L1B over pseudoinvariant desert sites. The standard polarization correction equation is used in combination with simulated at-sensor radiances using the second simulation of a satellite signal in the Solar Spectrum, Vector Radiative Transfer Code (6SV). We ignore the polarization contribution from the surface and a ratio approach is used for both 6SV-derived input parameters and observed TOA reflectances. Results indicate that significant gain corrections up to 25% are required near the end of scan for the 412 and 443 nm bands. The polarization correction reduces the seasonal fluctuations in reflectance trends and mirror side ratios from 30% and 12% to 10% and 5%, respectively, for the two bands. Comparison of the effectiveness of the polarization correction with the results from the NASA Ocean Biology Processing Group shows a good agreement in the corrected reflectance trending results and their seasonal fluctuations. Autors: Aisheng Wu;Xu Geng;Andrew Wald;Amit Angal;Xiaoxiong Xiong; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Jul 2017, volume: 55, issue:7, pages: 4168 - 4176 Publisher: IEEE
» Asymmetric Hysteresis Modeling and Compensation Approach for Nanomanipulation System Motion Control Considering Working-Range Effect
 Abstract:Atomic force microscope (AFM) has been defined as the one of the most powerful instruments to explore micro/nanoworld in various fields. To lower imaging noise, AFMs are commonly equipped with open-loop nanopositioners (scanners). However, the hysteretic effect of the AFM positioners is a dominate factor that increases the position error during AFM-based manipulations. To reduce hysteresis, inverse compensation approach is an effective solution. Normally, one compensator is designed for the manipulation task with maximum working range, which may not be efficient enough for maintaining uniform accuracy for tasks with different working ranges. The objective of this study is to develop a working-range adapted compensator to tackle this challenge. First, a generalized method that can precisely model various types of hysteresis is required. To fulfill this, a flexible Prandtl–Ishlinskii (PI) type model, named extended unparallel PI model, is employed. Based on this model, an implicit hysteresis compensation approach is developed, and its stability condition and control gain optimization approach are proposed. Combining the modeling and compensation approaches, a working-range adapted hysteresis compensator is finally established. Experimental results demonstrate that the mean control errors of the compensator are uniformly below in different working ranges. Autors: Zhiyong Sun;Bo Song;Ning Xi;Ruiguo Yang;Lina Hao;Yongliang Yang;Liangliang Chen; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5513 - 5523 Publisher: IEEE
» Asymptotic Analysis of Area Spectral Efficiency and Energy Efficiency in PPP Networks With SLNR Precoder
 Abstract:This paper aims at characterizing the energy efficiency (EE)—area spectral efficiency (ASE) tradeoff in random geometry networks with multiple-antenna arrays at base stations (BSs). In particular, ASE and EE are studied with respect to the transmit power when BSs use a signal-to-leakage-plus-noise ratio (SLNR) precoder. When the static power consumption cannot be neglected, EE behaves linearly with respect to ASE before a sharp decreasing of EE due to the interference-limited characteristic of the network. Our contribution relies on the derivation of a closed-form expression for ASE with SLNR precoder in the asymptotic regime, i.e., when the number of antennas and users grows to infinity, using stochastic geometry. We derive EE from a linear power consumption model afterwards. Unlike conventional SLNR precoders, the average signal-to-interference-plus-noise ratio and the leakage to other cells are considered in a geometry-dependent network. Extensive Monte Carlo simulations show that despite the asymptotic nature of the theoretical analysis, the closed-form expressions are tight with respect to simulations even for the moderate number of antennas and users. Hence, the analysis can be used for realistic network performance analysis. Autors: Ahmad Mahbubul Alam;Philippe Mary;Jean-Yves Baudais;Xavier Lagrange; Appeared in: IEEE Transactions on Communications Publication date: Jul 2017, volume: 65, issue:7, pages: 3172 - 3185 Publisher: IEEE
» Asymptotic Analysis of Plane Wave Scattering by a Fast Moving PEC Wedge
 Abstract:This contribution is concerned with the exact and asymptotic scattering of an oblique incident time-harmonic electromagnetic plane wave from a fast moving perfectly electric conducting wedge. By utilizing the Lorentz transformation and applying Maxwelln’s boundary conditions in the (scatterer) co-moving frame, an exact solution for the total fields is obtained in both the co-moving (scatterer) and the laboratory (incident field) frames. The fields are evaluated asymptotically in the high frequency regime in which the scattered field is presented as a sum of three wave types: the direct (reflected) wave, a shadowing wave, and a diffraction wave. Novel relativistic wave phenomena that are associated with the scatterer dynamics are explored. Autors: Ram Tuvi;Timor Melamed; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3638 - 3644 Publisher: IEEE
» Asynchronous Non-Generational Model to Parallelize Metaheuristics: A Bioinformatics Case Study
 Abstract:The integration of parallel computing techniques into metaheuristics has traditionally represented a promising approach to tackle computationally demanding optimization problems. In the last years, metaheuristics have evolved by including more complex search mechanisms whose parallelization often leads to performance issues under classic parallel schemes. This work investigates the asynchronous non-generational parallelization model, which is aimed at dealing with performance pitfalls by allowing worker threads to behave as asynchronous independent agents. We incorporate asynchronous principles into a recently proposed metaheuristic for multiobjective optimization, the Indicator-Based Multiobjective Bat Algorithm, and apply the resulting approach to solve a real-world problem in the bioinformatics domain: the reconstruction of evolutionary histories. Experiments on multicore multiprocessor systems comprising up to 64 cores reveal the suitability of the model to address the main challenges of the metaheuristic design under study, outperforming other implementations and methods in terms of parallel performance while also achieving significant solution quality. Autors: Sergio Santander-Jiménez;Miguel A. Vega-Rodríguez; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Jul 2017, volume: 28, issue:7, pages: 1825 - 1838 Publisher: IEEE
» Attenuation Induced by Water Vapor Along Earth-Space Links: Selecting the Most Appropriate Prediction Method
 Abstract:This communication presents an improved approximate method for the estimation of water vapor attenuation along Earth-space slant paths, over the 1–350-GHz frequency range. Evaluated against a large set of radiosonde data, the proposed method provides more accurate results than those delivered by the current alternative approximation methods included in Annex 2 of recommendation ITU-R P.676-10. This result is important as it sheds light on which approximate water vapor attenuation model should be selected for predictions along Earth-space slant paths. Autors: Lorenzo Luini;Carlo Riva;L. Emiliani; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3806 - 3808 Publisher: IEEE
» Autocorrelation Analysis as a Technique to Study Physical Mechanisms of MOSFET Low-Frequency Noise
 Abstract:A low-frequency noise (LFN) analysis technique is introduced, based on the autocorrelation of the LFN spectra in terms of frequency, biasing, and temperature. This technique reveals information about the mechanisms behind 1/ noise that is difficult to obtain otherwise. These correlation analyses provide strong evidence that the LFN of both nMOS and pMOS transistors is mainly composed of the superposition of thermally activated random telegraph signals (RTSs). The methodology enables quantification and validation of old and new LFN models, and, therefore, helps to clarify the relation between RTS and 1/ that is still frequently debated in the literature. Autors: Thiago H. Both;Jeroen A. Croon;Maurício Banaszeski da Silva;Hans P. Tuinhout;Andries J. Scholten;Adrie Zegers-van Duijnhoven;Gilson I. Wirth; Appeared in: IEEE Transactions on Electron Devices Publication date: Jul 2017, volume: 64, issue:7, pages: 2919 - 2926 Publisher: IEEE
» Automated Compression Device for Viscoelasticity Imaging
 Abstract:Noninvasive measurement of tissue viscoelastic properties is gaining more attention for screening and diagnostic purposes. Recently, measuring dynamic response of tissue under a constant force has been studied for estimation of tissue viscoelastic properties in terms of retardation times. The essential part of such a test is an instrument that is capable of creating a controlled axial force and is suitable for clinical applications. Such a device should be lightweight, portable, and easy to use for patient studies to capture tissue dynamics under external stress. In this paper, we present the design of an automated compression device for studying the creep response of materials with tissue-like behaviors. The device can be used to apply a ramp-and-hold force excitation for a predetermined duration of time and it houses an ultrasound probe for monitoring the creep response of the underlying tissue. To validate the performance of the device, several creep tests were performed on tissue-mimicking phantoms, and the results were compared against those from a commercial mechanical testing instrument. Using a second-order Kelvin–Voigt model and surface measurement of the forces and displacements, retardation times and were estimated from each test. These tests showed strong agreement between our automated compression device and the commercial mechanical testing system, with an average relative error of 2.9% and 12.4%, for and , respectively. Also, we present the application of compression device to measure local retardation times for four different p- antoms with different size and stiffness. Autors: Alireza Nabavizadeh;Randall R. Kinnick;Mahdi Bayat;Carolina Amador;Matthew W. Urban;Azra Alizad;Mostafa Fatemi; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Jul 2017, volume: 64, issue:7, pages: 1535 - 1546 Publisher: IEEE
» Automated Online Exam Proctoring
 Abstract:Massive open online courses and other forms of remote education continue to increase in popularity and reach. The ability to efficiently proctor remote online examinations is an important limiting factor to the scalability of this next stage in education. Presently, human proctoring is the most common approach of evaluation, by either requiring the test taker to visit an examination center, or by monitoring them visually and acoustically during exams via a webcam. However, such methods are labor intensive and costly. In this paper, we present a multimedia analytics system that performs automatic online exam proctoring. The system hardware includes one webcam, one wearcam, and a microphone for the purpose of monitoring the visual and acoustic environment of the testing location. The system includes six basic components that continuously estimate the key behavior cues: user verification, text detection, voice detection, active window detection, gaze estimation, and phone detection. By combining the continuous estimation components, and applying a temporal sliding window, we design higher level features to classify whether the test taker is cheating at any moment during the exam. To evaluate our proposed system, we collect multimedia (audio and visual) data from subjects performing various types of cheating while taking online exams. Extensive experimental results demonstrate the accuracy, robustness, and efficiency of our online exam proctoring system. Autors: Yousef Atoum;Liping Chen;Alex X. Liu;Stephen D. H. Hsu;Xiaoming Liu; Appeared in: IEEE Transactions on Multimedia Publication date: Jul 2017, volume: 19, issue:7, pages: 1609 - 1624 Publisher: IEEE
» Automated Planning for Robotic Cleaning Using Multiple Setups and Oscillatory Tool Motions
 Abstract:This paper presents planning algorithms for robotic cleaning of stains on nonplanar surfaces. Access to different portions of the stain may require frequent repositioning and reorienting of the object. Some portions with prominent stain may require multiple passes to remove the stain completely. Two robotic arms have been used in the experiments. The object is immobilized with one arm and the cleaning tool is manipulated with the other. The algorithm generates a sequence of reorientation and repositioning moves required to clean the part after analyzing the stain. The plan is generated by accounting for the kinematic constraints of the robot. Our algorithm uses a depth-first branch-and-bound search to generate setup plans. Cleaning trajectories are generated and optimal cleaning parameters are selected by the algorithm. We have validated our approach through numerical simulations and robotic cleaning experiments with two KUKA robots.Note to Practitioners—We encounter nonrepetitive cleaning tasks everyday in both industrial and household environments. Variations in stain pattern, geometry, and material of the object make it difficult to manually program robots for such tasks. In this paper, we present planning algorithms to automate the cleaning task using robots. The practical impact of our approach is evidenced by the actual robot results involving realistic examples like cleaning of hard paint stains on curved surfaces and rust on metal surfaces. Practitioners from industry can use the methods presented in this paper to develop automated robotic systems for nonrepetitive tasks like cleaning and polishing. Our approach caters to the primary requirements of these applications like multiple setups, multiple passes within each setup, and determination of optimal motion parameters like velocity, force, and oscillation frequency of the cleaning tool. Autors: Ariyan M. Kabir;Krishnanand N. Kaipa;Jeremy Marvel;Satyandra K. Gupta; Appeared in: IEEE Transactions on Automation Science and Engineering Publication date: Jul 2017, volume: 14, issue:3, pages: 1364 - 1377 Publisher: IEEE
» Automatic Detection of Defects in Tire Radiographic Images
 Abstract:This paper is about the detection of tire defects in multi-textural radiographic images. We consider the tire defects characterization problem in ways of local regularity analysis and scale characteristic. Optimal scale and threshold parameters are selected using a defect edge measurement model to frame defect edge detection. This framework distinguishes the defects from the background textures. Finally, a novel method for detection of tire defects is proposed based on wavelet multiscale analysis. We provide examples with a consistent dataset of 400 images selected over 3700 industrial images in order to illustrate and validate the obtained results which demonstrate substantial improvement over the state of the art. Autors: Yan Zhang;Dimitri Lefebvre;Qingling Li; Appeared in: IEEE Transactions on Automation Science and Engineering Publication date: Jul 2017, volume: 14, issue:3, pages: 1378 - 1386 Publisher: IEEE
» Automatic Detection of Marine Gas Seeps Using an Interferometric Sidescan Sonar
 Abstract:There is a significant need for reliable, cost-effective, and preferably automatic methods for detecting and monitoring marine gas seeps. Seeps at the seafloor may originate from natural sources including sediments releasing biogenic methane and volcanoes releasing CO2, or from man-made constructions such as pipelines or well heads, and potentially also from subseafloor CO2 storage sites. Improved seep detection makes it possible to estimate the amount of greenhouse gases entering the oceans, and to promptly detect and address potential leaks to reduce environmental and economical consequences. Sonar is an excellent tool for seep detection due to the strong acoustic backscatter properties of gas-filled bubbles in water. Existing methods for acoustic seep detection include multibeam and sidescan surveying, as well as active and passive sensors mounted on a stationary platform. In this work, we develop a new method for automatic seep detection using an interferometric sidescan sonar. We apply signal processing techniques combined with knowledge about acoustical and spatial properties of seeps for improved detectability. The proposed method fills an important gap in existing technology—the ability to automatically detect a seep during a single pass with an autonomous underwater vehicle (AUV) equipped with an interferometric sidescan sonar. Results from simulations as well as field data from two leaking abandoned wells in the North Sea indicate that small seeps are consistently detected on a sandy seafloor even when the observation time is limited (a single pass with the AUV). We explore the detection capability for different seafloor types ranging from silt to gravel. Autors: Ann Elisabeth Albright Blomberg;Torstein Olsmo Sæbø;Roy Edgar Hansen;Rolf Birger Pedersen;Andreas Austeng; Appeared in: IEEE Journal of Oceanic Engineering Publication date: Jul 2017, volume: 42, issue:3, pages: 590 - 602 Publisher: IEEE
» Automatic Identification of Pathology-Distorted Retinal Layer Boundaries Using SD-OCT Imaging
 Abstract:Objective: We propose an effective automatic method for identification of four retinal layer boundaries from the spectral domain optical coherence tomography images in the presence and absence of pathologies and morphological changes due to disease. Methods: The approach first finds an approximate location of three reference layers and then uses these to bound the search space for the actual layers, which is achieved by modeling the problem as a graph and applying Dijkstra's shortest path algorithm. The edge weight between nodes is determined using pixel distance, slope similarity to a reference, and nonassociativity of the layers, which is designed to overcome the distorting effects that pathology can play in the boundary determination. Results: The accuracy of our method was evaluated on three different datasets. It outperforms the current five state-of-the-art methods. On average, the mean and standard deviation of the root-mean-square error in the form of mean standard deviation in pixels for our method is 1.57 0.69, which is lower than compared to the existing top five methods of 16.17 22.64, 6.66 9.11, 5.70 10.54, 3.69 2.04, and 2.29 1.54. Conclusion: Our method is highly accurate, robust, reliable, and consistent. This identification can enable to quantify the biomarkers of the retina in large-scale study for assessing, monitoring di- ease progression, as well as early detection of retinal diseases. Significance: Identification of these boundaries can help to determine the loss of neuroretinal cells or layers and the presence of retinal pathology, which can be used as features for the automatic determination of the stages of retinal diseases. Autors: Md Akter Hussain;Alauddin Bhuiyan;Andrew Turpin;Chi D. Luu;R. Theodore Smith;Robyn H. Guymer;Ramamohanrao Kotagiri; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Jul 2017, volume: 64, issue:7, pages: 1638 - 1649 Publisher: IEEE
» Automatic Modulation Classification of Overlapped Sources Using Multiple Cumulants
 Abstract:Automatic modulation classification (AMC) for overlapped sources plays an important role in spectrum monitoring and signal interception. In this paper, we propose a feature-based AMC framework for multiple overlapped sources. The framework first separates the overlapped sources via blind channel estimation and then conducts novel maximum-likelihood-based multicumulant classification (MLMC) for each of the sources. MLMC employs multiple cumulants of arbitrary orders and arbitrary lags as discriminating features and a maximum likelihood ratio test for decision making. Hence, MLMC maximizes the probability of correct classification under the condition that the selected cumulants are utilized. Moreover, both the case with perfect channel estimation and the practically more relevant case with blind channel estimations, called fast independent component analysis and natural gradient independent component analysis, are presented to facilitate the signal separation process. Extensive simulations are also conducted to verify the validity and the superiority of the proposed framework and the MLMC algorithm. Autors: Sai Huang;Yuanyuan Yao;Zhiqing Wei;Zhiyong Feng;Ping Zhang; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Jul 2017, volume: 66, issue:7, pages: 6089 - 6101 Publisher: IEEE
» Automatic Quantification of Tumour Hypoxia From Multi-Modal Microscopy Images Using Weakly-Supervised Learning Methods
 Abstract:In recently published clinical trial results, hypoxia-modified therapies have shown to provide more positive outcomes to cancer patients, compared with standard cancer treatments. The development and validation of these hypoxia-modified therapies depend on an effective way of measuring tumor hypoxia, but a standardized measurement is currently unavailable in clinical practice. Different types of manual measurements have been proposed in clinical research, but in this paper we focus on a recently published approach that quantifies the number and proportion of hypoxic regions using high resolution (immuno-)fluorescence (IF) and hematoxylin and eosin (HE) stained images of a histological specimen of a tumor. We introduce new machine learning-based methodologies to automate this measurement, where the main challenge is the fact that the clinical annotations available for training the proposed methodologies consist of the total number of normoxic, chronically hypoxic, and acutely hypoxic regions without any indication of their location in the image. Therefore, this represents a weakly-supervised structured output classification problem, where training is based on a high-order loss function formed by the norm of the difference between the manual and estimated annotations mentioned above. We propose four methodologies to solve this problem: 1) a naive method that uses a majority classifier applied on the nodes of a fixed grid placed over the input images; 2) a baseline method based on a structured output learning formulation that relies on a fixed grid placed over the input images; 3) an extension to this baseline based on a latent structured output learning formulation that uses a graph that is flexible in terms of the amount and positions of nodes; and 4) a pixel-wise labeling based on a fully-convolutional neural network. Using a data set of 89 weakly annotated pairs of IF and HE images from eight tumors, we show that the quantitativ- results of methods (3) and (4) above are equally competitive and superior to the naive (1) and baseline (2) methods. All proposed methodologies show high correlation values with respect to the clinical annotations. Autors: Gustavo Carneiro;Tingying Peng;Christine Bayer;Nassir Navab; Appeared in: IEEE Transactions on Medical Imaging Publication date: Jul 2017, volume: 36, issue:7, pages: 1405 - 1417 Publisher: IEEE
» Auxiliary Beam Pair Enabled AoD and AoA Estimation in Closed-Loop Large-Scale Millimeter-Wave MIMO Systems
 Abstract:Channel estimation is of critical importance in millimeter-wave (mmWave) multiple-input multiple-output (MIMO) systems. Due to the use of large antenna arrays, low-complexity mmWave specific channel estimation algorithms are required. In this paper, an auxiliary beam pair design is proposed to provide high-resolution estimates of the channel’s angle-of-departure (AoD) and angle-of-arrival (AoA) for mmWave MIMO systems. By performing an amplitude comparison with respect to each auxiliary beam pair, a set of ratio measures that characterize the channel’s AoD and AoA are obtained by the receiver. Either the best ratio measure or the estimated AoD is quantized and fed back to the transmitter via a feedback channel. The proposed technique can be incorporated into control channel design to minimize initial access delay. Though the design principles are derived assuming a high-power regime, evaluation under more realistic assumption shows that by employing the proposed method, good angle estimation performance is achieved under various signal-to-noise ratio levels and channel conditions. Autors: Dalin Zhu;Junil Choi;Robert W. Heath; Appeared in: IEEE Transactions on Wireless Communications Publication date: Jul 2017, volume: 16, issue:7, pages: 4770 - 4785 Publisher: IEEE
» Back-Projection Cortical Potential Imaging: Theory and Results
 Abstract:Electroencephalography (EEG) is the single brain monitoring technique that is non-invasive, portable, passive, exhibits high-temporal resolution, and gives a directmeasurement of the scalp electrical potential. Amajor disadvantage of the EEG is its low-spatial resolution, which is the result of the low-conductive skull that “smears” the currents coming from within the brain. Recording brain activity with both high temporal and spatial resolution is crucial for the localization of confined brain activations and the study of brainmechanismfunctionality, whichis then followed by diagnosis of brain-related diseases. In this paper, a new cortical potential imaging (CPI) method is presented. The new method gives an estimation of the electrical activity on the cortex surface and thus removes the “smearing effect” caused by the skull. The scalp potentials are back-projected CPI (BP-CPI) onto the cortex surface by building a well-posed problem to the Laplace equation that is solved by means of the finite elements method on a realistic head model. A unique solution to the CPI problem is obtained by introducing a cortical normal current estimation technique. The technique is based on the same mechanism used in the well-known surface Laplacian calculation, followed by a scalp-cortex back-projection routine. The BP-CPI passed four stages of validation, including validation on spherical and realistic head models, probabilistic analysis (Monte Carlo simulation), and noise sensitivity tests. In addition, the BP-CPI was compared with the minimum norm estimate CPI approach and found superior for multi-source cortical potential distributions with very good estimation results (CC >0.97) on a realistic head model in the regions of interest, for two representative cases. The BP-CPI can be easily incorporated in different monitoring tools and help researchers by maintaining an accurate estimati- n for the cortical potential of ongoing or event-related potentials in order to have better neurological inferences from the EEG. Autors: Dror Haor;Reuven Shavit;Moshe Shapiro;Amir B. Geva; Appeared in: IEEE Transactions on Medical Imaging Publication date: Jul 2017, volume: 36, issue:7, pages: 1583 - 1595 Publisher: IEEE
» Backtracking Codebook Matching Algorithm Based on Codebook Correlation for Uplink SCMA System
 Abstract:In this letter, we have investigated the frequency diversity gain of a sparse code multiple access (SCMA) system to improve spectrum utilization by exploiting the codebook correlation in the SCMA system. To this end, a backtracking codebook matching (BCM) algorithm is proposed, whereby there are more successfully scheduled users, which are allocated the low-correlated codebooks. Simulation results exhibit the superiority of the BCM algorithm and the impact of codebook correlation on scheduling. Autors: Yanpeng Dai;Min Sheng;Junyu Liu;Lei Liu;Jiandong Li; Appeared in: IEEE Communications Letters Publication date: Jul 2017, volume: 21, issue:7, pages: 1597 - 1600 Publisher: IEEE
» Backward to Forward Scanning Periodic Leaky-Wave Antenna With Wide Scanning Range
 Abstract:A new type of circularly polarized printed periodic leaky-wave antenna (LWA) structure with a wide scanning range and reduced sidelobe level (SLL) is presented. Fifteen matched unit cells (UCs) are cascaded along the direction of propagation to provide seamless frequency scanning from 20 to 29 GHz with a scanning range of 95° from backward to forward quadrant. The open-stopband has been suppressed around the broadside region by matching the input impedance of the UC to the characteristic impedance of the transmission line. Two empirical transmission line models are presented to describe the behavior of the periodic LWA. Parametric study using full-wave simulation is used to improve the SLL and minimize the axial ratio of the circular polarization leading to a fully optimized periodic leaky LWA. Autors: Mohammad H. Rahmani;Dominic Deslandes; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3326 - 3335 Publisher: IEEE
» Balanced Proper Orthogonal Decomposition Applied to Magnetoquasi-Static Problems Through a Stabilization Methodology
 Abstract:Model order reduction (MOR) methods are applied in different areas of physics in order to reduce the computational time of large scale systems. It has been an active field of research for many years, in mechanics especially, but it is quite recent for magnetoquasi-static problems. Although the most famous method, the proper orthogonal decomposition (POD) has been applied for modeling many electromagnetic devices, this method can lack accuracy for low-order magnitude output quantities, like flux associated with a probe in regions where the field is low. However, the balanced POD (BPOD) is an MOR method, which takes into account these output quantities in its reduced model to render them accurately. Even if the BPOD may lead to unstable reduced systems, this can be overcome by a stabilization procedure. Therefore, the POD and the stabilized BPOD will be compared on a 3-D linear magnetoquasi-static field problem. Autors: Laurent Montier;Thomas Henneron;Benjamin Goursaud;Stéphane Clénet; Appeared in: IEEE Transactions on Magnetics Publication date: Jul 2017, volume: 53, issue:7, pages: 1 - 10 Publisher: IEEE
» Band-Selectively Tunable Electromagnetic Bandgap Structures With Open-Circuit Lines and Variable Capacitors
 Abstract:We discuss the band-selective tuning of specific bandgaps (BGs) in an electromagnetic BG (EBG) structure. Two variable capacitors (VCs) attached to an open-circuit line (an element of the EBG structure) are selectively excited by voltage standing waves in the open-circuit line, and they can selectively tune the first and second BGs. With the change in a VC by 4.8 pF, the first BG moves from 0.55 to 0.39 GHz with almost no shift of the second one, while the second BG is tuned from 1.61 to 1.29 GHz with a 1.8-pF change in the other VC. This tuning technique can be potentially applied to other microwave devices using resonant phenomena such as antennas and filters. Autors: Yoshiaki Kasahara;Hiroshi Toyao;Eiji Hankui; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Jul 2017, volume: 27, issue:7, pages: 615 - 617 Publisher: IEEE
» Bandpass Class-F Power Amplifier Based on Multifunction Hybrid Cavity–Microstrip Filter
 Abstract:This brief presents a filter-integrated high-efficiency class-F power amplifier (PA). The hybrid cavity–microstrip filtering circuit is employed not only to realize output impedance matching and the third-harmonic manipulation but also to provide high-selectivity bandpass responses. To fulfill the requirements of high-efficiency class-F PAs, cavity resonators and microstrip feeding structures are involved, and their benefits are fully exploited. The metal cavity resonator features a high value and, thus, low loss in the passband, resulting in high efficiency. Moreover, metal walls of cavities act as heat sink for the transistor. The microstrip feeding structures are used to improve the skirt selectivity and manipulate the third harmonic. Moreover, it features easy integration with the transistor, and thus, the transition between cavity and microstrip lines is eliminated. The hybrid filter is characterized based on filter synthesis theory. Complex impedance conversion analysis is carried out to guide the impedance transformation from 50 to a complex one desired by the transistor. For demonstration, a filtering PA operating at 2.4 GHz is designed and measured. It exhibits both high-selectivity bandpass responses and good PA performance with maximum power-added efficiency of 70.9% at 40.8-dBm output power. Autors: Qing-Yi Guo;Xiu Yin Zhang;Jin-Xu Xu;Yuan Chun Li;Quan Xue; Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs Publication date: Jul 2017, volume: 64, issue:7, pages: 742 - 746 Publisher: IEEE
» Bandpass-to-Bandstop Reconfigurable Tunable Filters with Frequency and Bandwidth Controls
 Abstract:A novel method is proposed for designing bandpass-to-bandstop reconfigurable tunable filters. The proposed method employs standard bandpass and bandstop design theory which does not require complex coupling synthesizing process, and can be applied for arbitrary-order bandpass-to-bandstop reconfigurable filters with both frequency and bandwidth control. Second-order and third-order bandpass-to-bandstop reconfigurable filters from 2 to 2.7 GHz were built to demonstrate the proposed method. The filters offer wide frequency and bandwidth tuning flexibility in both bandpass and bandstop modes, and occupy an area smaller than 20 mm mm on a substrate with relative dielectric constant substrate. Theory and measured results are presented with good agreement. Autors: Tao Yang;Gabriel M. Rebeiz; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Jul 2017, volume: 65, issue:7, pages: 2288 - 2297 Publisher: IEEE
» Battling the Extreme: A Study on the Power System Resilience
 Abstract:The electricity infrastructure is a critical lifeline system and of utmost importance to our daily lives. Power system resilience characterizes the ability to resist, adapt to, and timely recover from disruptions. The resilient power system is intended to cope with low probability, high risk extreme events including extreme natural disasters and man-made attacks. With an increasing awareness of such threats, the resilience of power systems has become a top priority for many countries. Facing the pressing urgency for resilience studies, the objective of this paper is to investigate the resilience of power systems. It summarizes practices taken by governments, utilities, and researchers to increase power system resilience. Based on a thorough review on the existing metrics system and evaluation methodologies, we present the concept, metrics, and a quantitative framework for power system resilience evaluation. Then, system hardening strategies and smart grid technologies as means to increase system resilience are discussed, with an emphasis on the new technologies such as topology reconfiguration, microgrids, and distribution automation; to illustrate how to increase system resilience against extreme events, we propose a load restoration framework based on smart distribution technology. The proposed method is applied on two test systems to validify its effectiveness. In the end, challenges to the power system resilience are discussed, including extreme event modeling, practical barriers, interdependence with other critical infrastructures, etc. Autors: Zhaohong Bie;Yanling Lin;Gengfeng Li;Furong Li; Appeared in: Proceedings of the IEEE Publication date: Jul 2017, volume: 105, issue:7, pages: 1253 - 1266 Publisher: IEEE
» Bayesian Estimation of Intrinsic Tissue Oxygenation and Perfusion From RGB Images
 Abstract:Multispectral imaging (MSI) can potentially assist the intra-operative assessment of tissue structure, function and viability, by providing information about oxygenation. In this paper, we present a novel technique for recovering intrinsic MSI measurements from endoscopic RGB images without custom hardware adaptations. The advantage of this approach is that it requires no modification to existing surgical and diagnostic endoscopic imaging systems. Our method uses a radiometric color calibration of the endoscopic camera’s sensor in conjunction with a Bayesian framework to recover a per-pixel measurement of the total blood volume (THb) and oxygen saturation (SO2) in the observed tissue. The sensor’s pixel measurements are modeled as weighted sums over a mixture of Poisson distributions and we optimize the variables SO2 and THb to maximize the likelihood of the observations. To validate our technique, we use synthetic images generated from Monte Carlo physics simulation of light transport through soft tissue containing sub-surface blood vessels. We also validate our method on in vivo data by comparing it to a MSI dataset acquired with a hardware system that sequentially images multiple spectral bands without overlap. Our results are promising and show that we are able to provide surgeons with additional relevant information by processing endoscopic images with our modeling and inference framework. Autors: Geoffrey Jones;Neil T. Clancy;Yusuf Helo;Simon Arridge;Daniel S. Elson;Danail Stoyanov; Appeared in: IEEE Transactions on Medical Imaging Publication date: Jul 2017, volume: 36, issue:7, pages: 1491 - 1501 Publisher: IEEE
» Bayesian Nonparametric Relational Topic Model through Dependent Gamma Processes
 Abstract:Traditional relational topic models provide a successful way to discover the hidden topics from a document network. Many theoretical and practical tasks, such as dimensional reduction, document clustering, and link prediction, could benefit from this revealed knowledge. However, existing relational topic models are based on an assumption that the number of hidden topics is known a priori, which is impractical in many real-world applications. Therefore, in order to relax this assumption, we propose a nonparametric relational topic model using stochastic processes instead of fixed-dimensional probability distributions in this paper. Specifically, each document is assigned a Gamma process, which represents the topic interest of this document. Although this method provides an elegant solution, it brings additional challenges when mathematically modeling the inherent network structure of typical document network, i.e., two spatially closer documents tend to have more similar topics. Furthermore, we require that the topics are shared by all the documents. In order to resolve these challenges, we use a subsampling strategy to assign each document a different Gamma process from the global Gamma process, and the subsampling probabilities of documents are assigned with a Markov Random Field constraint that inherits the document network structure. Through the designed posterior inference algorithm, we can discover the hidden topics and its number simultaneously. Experimental results on both synthetic and real-world network datasets demonstrate the capabilities of learning the hidden topics and, more importantly, the number of topics. Autors: Junyu Xuan;Jie Lu;Guangquan Zhang;Richard Yi Da Xu;Xiangfeng Luo; Appeared in: IEEE Transactions on Knowledge and Data Engineering Publication date: Jul 2017, volume: 29, issue:7, pages: 1357 - 1369 Publisher: IEEE
» BDMA for Millimeter-Wave/Terahertz Massive MIMO Transmission With Per-Beam Synchronization
 Abstract:We propose beam division multiple access (BDMA) with per-beam synchronization (PBS) in time and frequency for wideband massive multiple-input multiple-output (MIMO) transmission over millimeter-wave (mmW)/Terahertz (THz) bands. We first introduce a physically motivated beam domain channel model for massive MIMO and demonstrate that the envelopes of the beam domain channel elements tend to be independent of time and frequency when both the numbers of antennas at base station and user terminals (UTs) tend to infinity. Motivated by the derived beam domain channel properties, we then propose PBS for mmW/THz massive MIMO. We show that both the effective delay and Doppler frequency spreads of wideband massive MIMO channels with PBS are reduced by a factor of the number of UT antennas compared with the conventional synchronization approaches. Subsequently, we apply PBS to BDMA, investigate beam scheduling to maximize the ergodic achievable rates for both uplink and downlink BDMA, and develop a greedy beam scheduling algorithm. Simulation results verify the effectiveness of BDMA with PBS for mmW/THz wideband massive MIMO systems in typical mobility scenarios. Autors: Li You;Xiqi Gao;Geoffrey Ye Li;Xiang-Gen Xia;Ni Ma; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Jul 2017, volume: 35, issue:7, pages: 1550 - 1563 Publisher: IEEE
» Beam-Domain Channel Estimation for FDD Massive MIMO Systems With Optimal Thresholds
 Abstract:Massive multiple-input multiple-output (MIMO) systems are expected to operate in the frequency-division duplex (FDD) mode, which is feasible in the channel environment with limited scattering. Since accurate channel estimation is critical for gaining unprecedented capacity, we investigate beam-domain channel estimation and feedback for FDD massive MIMO systems. In particular, we focus on the threshold-based method for channel estimation, where an enhanced estimator is proposed to exploit the common support among all beam-domain channels. For threshold-based estimation, we derive its closed-form mean-squared error (MSE) expression, and obtain an optimal threshold as a function of sparsity, noise variance, and channel variance, and a simplified threshold, which is a function of noise variance only. For the enhanced estimator, we present a threshold to identify the common support, with which an algorithm is designed to improve the estimation accuracy. As for channel feedback, we suggest to feed back only significant elements (above the given threshold) in the beam domain. Numerical results validate our derived MSE expression and demonstrate the superior performance of proposed threshold-based estimators. Autors: Xin Xiong;Xiaodong Wang;Xiqi Gao;Xiaohu You; Appeared in: IEEE Transactions on Wireless Communications Publication date: Jul 2017, volume: 16, issue:7, pages: 4669 - 4682 Publisher: IEEE
» Beamspace SU-MIMO for Future Millimeter Wave Wireless Communications
 Abstract:For future networks [i.e., the fifth generation (5G) wireless networks and beyond], millimeter-wave (mmWave) communication with large available unlicensed spectrum is a promising technology that enables gigabit multimedia applications. Thanks to the short wavelength of mmWave radio, massive antenna arrays can be packed into the limited dimensions of mmWave transceivers. Therefore, with directional beamforming, both mmWave transmitters (MTXs) and mmWave receivers (MRXs) are capable of supporting multiple beams in 5G networks. However, for the transmission between an MTX and an MRX, most works have only considered a single beam, which means that they do not make full potential use of mmWave. Furthermore, the connectivity of single beam transmission can easily be blocked. In this context, we propose a single-user (SU) multi-beam concurrent transmission scheme for future mmWave networks with multiple reflected paths. Based on spatial spectrum reuse, the scheme can be described as a multiple-input multiple-output (MIMO) technique in beamspace (i.e., in the beam-number domain). Moreover, this paper investigates the challenges and potential solutions for implementing this scheme, including multi-beam selection, cooperative beam tracking, multi-beam power allocation, and synchronization. The theoretical and numerical results show that the proposed beamspace SU-MIMO can largely improve the achievable rate of the transmission between an MTX and an MRX and, meanwhile, can maintain the connectivity. Autors: Qing Xue;Xuming Fang;Cheng-Xiang Wang; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Jul 2017, volume: 35, issue:7, pages: 1564 - 1575 Publisher: IEEE
» Beamwidth Switchable Planar Microstrip Series-Fed Slot Array Using Reconfigurable Synthesized Transmission Lines
 Abstract:A planar microstrip series-fed slot antenna array, providing two-dimensional (2-D) beamwidth-switching capability, is presented and demonstrated. A newly developed reconfigurable synthesized line was incorporated into the feed network of the slot array as ON/OFF RF switches to enable the reconfigurability. With the aid of varactor diodes, the synthesized line can be switched between two states at the same frequency. In one state, it functions as a 50- line for signal transmission, and in the other state, it is an open circuit for signal blockage. The switching is depended on the bias voltage, and the dc power consumption is very low. By wisely choosing the number of radiating elements, the E- and H-plane half-power beamwidths of the planar slot array can be shaped from (35°, 65°) to (15°, 31°). The broadside gain is varied from 7 to 14.5 dBi. The total efficiency remains better than 71%. Autors: Huy Nam Chu;Tzyh-Ghuang Ma; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3766 - 3771 Publisher: IEEE
» Bias-Independent and Self-Calibrated Electrical Method for Microwave Characterization of Dual-Parallel Mach–Zehnder Modulators Based on Two-Tone and Bias-Swing Modulation
 Abstract:A bias-independent and self-calibrated measurement is proposed for the high-frequency response of dual-parallel Mach–Zehnder modulators (DPMZMs) based on two-tone and bias-swing modulation. The two-tone and bias-swing sidebands beat with each other and generate the desired low-frequency beat notes, which allows to extracting the modulation depths and half-wave voltages of DPMZMs from the sub-MHz electrical spectrum analysis. Our measurement is bias-independent due to the insensitivity to the bias voltages of the DPMZM, and it avoids any correction for the roll-off responsivity of photodetection through the specific two-tone and bias-swing modulation. Our method is experimentally demonstrated and is compared with the traditional ones for the accuracy. The proposed electrical method features bias-independence and self-calibration, providing a low-frequency photodetection and spectrum analysis for measuring high-speed DPMZMs. Autors: Heng Wang;Shangjian Zhang;Xinhai Zou;Yali Zhang;Shuang Liu;Yong Liu; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Jul 2017, volume: 65, issue:7, pages: 2636 - 2643 Publisher: IEEE
» Bidirectional Current-Fed Half-Bridge (C) (LC)–(LC ) Configuration for Inductive Wireless Power Transfer System
 Abstract:This paper contributes to the analysis and development of a new power electronics system for bidirectional wireless power transfer (WPT). The major focus is the analysis and implementation of a new current-fed resonant topology with current-sharing and voltage-doubling features. A new bidirectional WPT system with current-fed half-bridge voltage-doubler circuit is proposed and analyzed with series–parallel and series resonant networks. Traditionally used parallel L–C resonant tank in transmitter circuit with current-fed WPT topology causes higher voltage stress across the inverter devices to compensate the reactive power consumed by the loosely coupled coil. In the proposed topology, this is mitigated by adding a suitably designed capacitor in series with the transmitter coil; thus, developing a series–parallel CLC tank. Detailed analysis and design is reported for both grid-to-vehicle and vehicle-to-grid operations. The power flow is controlled through variable frequency modulation. Soft switching of the devices is obtained irrespective of the load current. A proof-of-concept experimental hardware prototype rated at 1.2 kW is developed and tested. Experimental results are presented to verify the analysis and demonstrate the performance of the system with bidirectional power flow. Autors: Suvendu Samanta;Akshay Kumar Rathore;Duleepa J. Thrimawithana; Appeared in: IEEE Transactions on Industry Applications Publication date: Jul 2017, volume: 53, issue:4, pages: 4053 - 4062 Publisher: IEEE
» Binary-Tree Based Estimation of File Requests for Efficient Data Replication
 Abstract:Recently, data replication has received considerable attention in the field of grid computing. The main goal of data replication algorithms is to optimize data access performance by replicating the most popular files. When a file does not exist in the node where it was requested, it necessarily has to be transferred from another node, causing delays in the completion the file requests. The general idea behind data replication is to keep track of the most popular files requested in the grid and create copies of them in selected nodes. In this way, more file requests can be completed over a period of time and average job execution time is reduced. In this paper, we introduce an algorithm that estimates the potential of the files located in each node of the grid, using a binary tree structure. Also, the file scope and the file type are taken into account. By potential of a file, we mean its increasing or decreasing demand over a period of time. The file scope generally refers to the extent of the group of users which are interested or potentially interested in a file. The file types are divided into read and write intensive. Our scheme mainly promotes the high-potential files for replication, based on the temporal locality principle. The simulation results indicate that the proposed scheme can offer better data access performance in terms of the hit ratio and the average job execution time, compared to other state-of-the-art strategies. Autors: Stavros Souravlas;Angelo Sifaleras; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Jul 2017, volume: 28, issue:7, pages: 1839 - 1852 Publisher: IEEE
» Biparametric Wave Digital Filters
 Abstract:We propose a novel class of wave digital filters (WDFs), called Biparametric WDFs (BWDFs), whose power-normalized waves are defined as having two free parameters instead of just one. We explore the advantages brought by this generalization by first deriving the scattering relations and the corresponding adaptation conditions for the most common circuit elements. We then show that the added free parameters allow us to define adaptors whose ports can all be simultaneously adapted; and that these adaptors are reciprocal and their scattering relations can be defined to be multiplierless and independent of the circuit parameters. We also show that the computational cost and memory requirements of BWDFs turn out to be reduced with respect to traditional WDFs based on power-normalized waves. We then discuss the impact of this generalization on the ability of wave digital structures of this sort to accommodate nonlinear elements. We finally develop explicit wave mappings for nonlinear diodes, and discuss some examples of applications to specific nonlinear circuits (i.e., an envelope detector, an unbiased double diode clipper, and a biased double diode clipper). Autors: Alberto Bernardini;Augusto Sarti; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Jul 2017, volume: 64, issue:7, pages: 1826 - 1838 Publisher: IEEE
» Black-Box Calibration for ADCs With Hard Nonlinear Errors Using a Novel INL-Based Additive Code: A Pipeline ADC Case Study
» Blind Deconvolution Meets Blind Demixing: Algorithms and Performance Bounds
 Abstract:Suppose that we have sensors and each one intends to send a function (e.g., a signal or an image) to a receiver common to all sensors. During transmission, each gets convolved with a function . The receiver records the function , given by the sum of all these convolved signals. When and under which conditions is it possible to recover the individual signals and the blurring functions from just one received signal ? This challenging problem, which intertwines blind deconvolution with blind demixing, appears in a variety of applications, such as audio processing, image processing, neuroscience, spectroscopy, and astronomy. It is also expected to play a central role in connection with the future Internet-of-Things. We will prove that under reasonable and practical assumptions, it is possible to solve this, otherwise, highly ill-posed problem and recover the transmitted functions and the impulse responses in a robust, reliable, and efficient manner, from just one single received function by solving a semidefinite program. We derive explicit bounds on the number of measurements needed for successful recovery and prove that our method is robust in the presence of noise. Our theory is actually suboptimal, since numerical experiments demonstrate that, quite remarkably, recovery is still possible if the number of measurements is close to the number of degrees of freedom. Autors: Shuyang Ling;Thomas Strohmer; Appeared in: IEEE Transactions on Information Theory Publication date: Jul 2017, volume: 63, issue:7, pages: 4497 - 4520 Publisher: IEEE
» Blind Iterative Nonlinear Distortion Compensation Based on Thresholding
 Abstract:The sampling process in electrical devices includes nonlinear distortion that needs to be compensated to boost up the system efficiency. In this brief, a blind method is suggested for nonlinear distortion compensation. The core idea is to leverage the sparsity of the signal to cope with the ill-posedness of the distortion compensation task. The proposed scheme is an iterative method based on out of support energy minimization, in which the support information is not available. An adaptive thresholding operator is used to give a rough approximation of the support according to the estimated signal at each iteration. Various simulation scenarios have validated the capability of the suggested scheme in compensating the miscellaneous distorting functions and have confirmed its superiority over the other techniques. Autors: Masoumeh Azghani;Amirata Ghorbani;Farokh Marvasti; Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs Publication date: Jul 2017, volume: 64, issue:7, pages: 852 - 856 Publisher: IEEE
» BNB Method for No-Reference Image Quality Assessment
 Abstract:It is challenging to quantitatively assess image quality in real time without a reference image while achieving human-level perception performance. In this paper, we present a no-reference (NR) image quality assessment (IQA) method called BNB (an acronym for blurriness, noisiness, and blockiness). Our BNB method quantifies the blurriness, noisiness, and blockiness of a given image, which are considered as three critical factors affecting users’ quality of experience. This method is rooted in the observation that for any image, the difference between any two adjacent pixel values follows a generalized Laplace distribution with zero mean. This Laplace distribution changes differently when the image experiences various types of artifacts, i.e., blurriness, noisiness, and blockiness. To construct a metric for each BNB artifact, we first extract features for each type of artifacting from the changing Laplace distribution and then identify the quantitative relationship between the feature value and the variation of the artifact. Given human perception scores of a popular image database, we use the k-nearest neighbor algorithm to map our three BNB metrics of an image to a human perception score. Experimental results reveal that the image quality score obtained from our BNB method has higher correlation with human perceptual scores in addition to requiring notably less computation compared with existing NR IQA methods. Autors: Ruigang Fang;Richard Al-Bayaty;Dapeng Wu; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Jul 2017, volume: 27, issue:7, pages: 1381 - 1391 Publisher: IEEE
» Boost-Integrated Two-Switch Forward AC–DC LED Driver With High Power Factor and Ripple-Free Output Inductor Current
 Abstract:This paper proposes a boost-integrated two-switch forward ac–dc light-emitting diode (LED) driver with a high power factor and ripple-free output inductor current. In the proposed LED driver, the maximum switch voltages are clamped to the voltage level of the dc-link capacitor without an RCD snubber circuit by adopting a two-switch forward structure, and the magnetizing inductor energy is restored in the dc-link capacitor to prevent the magnetizing inductor from saturating without a tertiary winding. Moreover, the relatively small capacitance can be utilized by the output capacitor, as the output inductor current ripple is significantly reduced by the additional circuit, unlike in the conventional LED driver. Hence, the LC filter at the output stage is simplified. The proposed LED driver has a high power factor and the power efficiency is improved. The theoretical analysis results of the proposed LED driver are verified on an output 24 [V]–1.4 [A] prototype. Autors: Sin-Woo Lee;Hyun-Lark Do; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Jul 2017, volume: 64, issue:7, pages: 5789 - 5796 Publisher: IEEE
» Bridging Presilicon and Postsilicon Debugging by Instruction-Based Trace Signal Selection in Modern Processors
 Abstract:Although using presilicon information in postsilicon debugging phase seems interesting, space and time limitations of existing formal verification tools restrict the possibility of this idea. In this paper, the effective usage of presilicon information to enhance postsilicon trace signal selection in modern processors is discussed. Furthermore, a novel architecture for dynamic per-cycle selection of signals based on the present instruction is implemented and synthesized. In presilicon phase, first, a set of controlling signals and their corresponding rules are extracted manually. Based on these rules, a set of data from model is extracted using an automatic formal method, which determines which signals should be traced at postsilicon according to the values of controlling signals. This mechanism alone results in an average of 79% and 54% bits to be pruned from the traceable signals for Leon3 and multithreaded DLX processors and 86% and 75% improvement when used in conjunction with traditional methods, respectively. Autors: Fatemeh Refan;Bijan Alizadeh;Zainalabedin Navabi; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Jul 2017, volume: 25, issue:7, pages: 2059 - 2070 Publisher: IEEE
» Broadband Efficiency-Enhanced Mutually Coupled Harmonic Postmatching Doherty Power Amplifier
 Abstract:The postmatching topology is an effective approach for broadening the bandwidth of a Doherty power amplifier (DPA). Its efficiency can be enhanced using a second-harmonic short-circuit network (SHSN), but at the expense of bandwidth. In this paper, the SHSNs with mutual coupling are proposed to achieve efficiency enhancement without sacrificing bandwidth. A broadband Doherty amplifier was designed and fabricated based on commercially available gallium nitride HEMT (Cree CGH 40006P) devices to validate the proposed technique. Under continuous-wave excitation, the measured results of the proposed DPA demonstrated that a wide bandwidth of 40% (1.8–2.7 GHz) can be maintained, with the 6-dB back-off drain efficiency between 47.5% and 54%. Using a wideband code-division multiple access 3GPP test signal with the peak-to-average power ratio of 6.6 dB, the adjacent channel power ratio over the entire frequency band is below −30 and −25 dBc at a 6-dB back-off and saturation, respectively. Autors: Xin Yu Zhou;Shao Yong Zheng;Wing Shing Chan;Shichang Chen;Derek Ho; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Jul 2017, volume: 64, issue:7, pages: 1758 - 1771 Publisher: IEEE
» Building Young Minds Brick by Brick
 Abstract:For working parents, there's an intensity to Thursdays that can border on the overwhelming. Status reports are due, kids have tests to prepare for, and meetings pile up from projects unfinished from the week, making my Outlook calendar look like one of Piet Mondrian's more colorful works. Careful observers of my calendar are apt to notice, in the weeks between September and December, blocks of time appearing with an peculiar subject: LEGO coaching. Autors: Lee Clontz; Appeared in: IEEE Potentials Publication date: Jul 2017, volume: 36, issue:4, pages: 30 - 35 Publisher: IEEE
» Bunch Current Measurement Using a High-Speed Photodetector at HLS II
 Abstract:This paper presents a novel bunch current measurement system based on an ultrafast photodetector and a high-speed digitizer at Hefei light source II (HLS II). We use a metal–semiconductor–metal photodetector to measure the emitted optical synchrotron radiation intensity directly, representing the bunch current intensity. To achieve bunch-by-bunch resolution, the sampling rate of the system is nearly 225 GS/s, which is achieved via a dedicated equivalent sampling algorithm. The detailed description of the experimental setup and the equivalent sampling algorithm are presented. According to preliminary tests of the daily operation mode and single-bunch mode, the measured root-mean-square of the beam current is ~1%, which shows that the new system satisfies the requirements for high-precision bunch current measurements. In addition, experimental results of the “HLS” Morse-code fill pattern mode demonstrate that this system could also be a convenient and robust tool for beam top-up modes in the future. Autors: Tianyu Zhou;Yongliang Yang;Baogen Sun;Ping Lu;Fangfang Wu;Jigang Wang;Zeran Zhou;Qing Luo;Qian Wang;Hao Li; Appeared in: IEEE Transactions on Nuclear Science Publication date: Jul 2017, volume: 64, issue:7, pages: 1886 - 1890 Publisher: IEEE
» Capacity Analysis of NOMA With mmWave Massive MIMO Systems
 Abstract:Non-orthogonal multiple access (NOMA), millimeter wave (mmWave), and massive multiple-input-multiple-output (MIMO) have been emerging as key technologies for fifth generation mobile communications. However, less studies have been done on combining the three technologies into the converged systems. In addition, how many capacity improvements can be achieved via this combination remains unclear. In this paper, we provide an in-depth capacity analysis for the integrated NOMA-mmWave-massive-MIMO systems. First, a simplified mmWave channel model is introduced by extending the uniform random single-path model with angle of arrival. Afterward, we divide the capacity analysis into the low signal to noise ratio (SNR) and high-SNR regimes based on the dominant factors of signal to interference plus noise ratio. In the noise-dominated low-SNR regime, the capacity analysis is derived by the deterministic equivalent method with the Stieltjes–Shannon transform. In contrast, the statistic and eigenvalue distribution tools are invoked for the capacity analysis in the interference-dominated high-SNR regime. The exact capacity expression and the low-complexity asymptotic capacity expression are derived based on the probability distribution function of the channel eigenvalue. Finally, simulation results validate the theoretical analysis and demonstrate that significant capacity improvements can be achieved by the integrated NOMA-mmWave-massive-MIMO systems. Autors: Di Zhang;Zhenyu Zhou;Chen Xu;Yan Zhang;Jonathan Rodriguez;Takuro Sato; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Jul 2017, volume: 35, issue:7, pages: 1606 - 1618 Publisher: IEEE
» Capacity Bounds for Discrete-Time, Amplitude-Constrained, Additive White Gaussian Noise Channels
 Abstract:The capacity-achieving input distribution of the discrete-time, additive white Gaussian noise (AWGN) channel with an amplitude constraint is discrete and seems difficult to characterize explicitly. A dual capacity expression is used to derive analytic capacity upper bounds for scalar and vector AWGN channels. The scalar bound improves on McKellips’ bound and is within 0.1 bit of capacity for all signal-to-noise ratios (SNRs). The 2-D bound is within 0.15 bits of capacity provably up to 4.5 dB; numerical evidence suggests a similar gap for all SNRs. As the SNR tends to infinity, these bounds are accurate and match with a volume-based lower bound. For the 2-D complex case, an analytic lower bound is derived by using a concentric constellation and is shown to be within 1 bit of capacity. Autors: Andrew Thangaraj;Gerhard Kramer;Georg Böcherer; Appeared in: IEEE Transactions on Information Theory Publication date: Jul 2017, volume: 63, issue:7, pages: 4172 - 4182 Publisher: IEEE
» Capacity Results for the Multicast Cognitive Interference Channel
 Abstract:The capacity region of the multicast Cognitive Inter-Ference Channel (CIFC) is investigated. This channel consists of two independent transmitters that wish to multicast two different messages, each to a different set of users. In addition, one of the transmitters—commonly referred to as the cognitive transmitter—has prior non-causal knowledge of both messages to be transmitted. This scenario subsumes some long-standing open problems, such as the interference channel, the broadcast channel, and multicast communications. The aim of this paper is the derivation of optimal interference mitigation techniques under different interference regimes. To this end, two settings, namely the multi-primary CIFC, i.e., and , and its complementary, the multi-secondary CIFC, i.e., and , are investigated as an attempt to build a thorough understanding for the more general multicast CIFC setting. It is shown that, for some interference regimes, well-known coding techniques for the standard CIFC remain still optimal under the constraint of multicasting to multiple users. However, in other interference regimes, capacity achieving coding and decoding schemes prove to be more involved. A careful combination of these coding schemes and new outer bounding techniques allows to characterize the capacity region for several classes of discrete memoryless and Gaussian multicast CIFC under different interference regimes. Autors: Meryem Benammar;Pablo Piantanida;Shlomo Shamai Shitz; Appeared in: IEEE Transactions on Information Theory Publication date: Jul 2017, volume: 63, issue:7, pages: 4119 - 4136 Publisher: IEEE
» Carbon-Based Pressure Sensors With Wavy Configuration
 Abstract:We demonstrate all-solution-processed pressure sensors consisting of carbon-based nano-composites with a wavy configuration using patterned polydimethylsiloxane molds. The sensitivity of the proposed sensors was increased by 36% at the applied pressure levels of 1 k N/. Significantly, the resistance was mostly recovered after a release from 3 M N/ without conspicuous hysteresis, and a very stable and robust operation was secured during the pressure and release cycle. Compared with the as-supplied pressure-sensitive rubber films, the carbon-based nano-composite with a wavy configuration exhibited gradual changes, including a linear change in the low-pressure regime. Autors: Ban-Suk Park;Tae-Jun Ha; Appeared in: IEEE Electron Device Letters Publication date: Jul 2017, volume: 38, issue:7, pages: 979 - 982 Publisher: IEEE
» Carrier Aggregation for Cooperative Cognitive Radio Networks
 Abstract:The ever-increasing demand for mobile Internet and high-data-rate applications poses unique challenging requirements for 5G mobile networks, including spectrum limitations and massive connectivity. Cognitive radio and carrier aggregation (CA) have recently been proposed as promising technologies to overcome these challenges. In this paper, we investigate joint relay selection and optimal power allocation in an underlay cooperative cognitive radio with CA, taking into account the availability of multiple carrier components in two frequency bands, subject to outage probability requirements for primary users (PUs). The secondary user network employs relay selection, where the relay that maximizes the end-to-end sum rate is selected, assuming both decode-and-forward and amplify-and-forward relaying. The resulting optimization problems are optimally solved using convex optimization tools, i.e., dual decomposition and an efficient iterative method, allowing their application in practical implementations. Simulation results illustrate that the proposed configuration exploits the available degrees of freedom efficiently to maximize the SU rate, while meeting the PU average outage probability constraints. Autors: Panagiotis D. Diamantoulakis;Koralia N. Pappi;Sami Muhaidat;George K. Karagiannidis;Tamer Khattab; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Jul 2017, volume: 66, issue:7, pages: 5904 - 5918 Publisher: IEEE
» Centralized and Distributed Energy Efficiency Designs in Wireless Backhaul HetNets
 Abstract:This paper studies the joint design of downlink transmit beamforming and power allocation in two-tier wireless backhaul small cell heterogeneous networks. We consider reverse time division duplexing combined with equal spectrum splitting between two tiers for interference mitigation. We formulate a constrained optimization problem with the objective of maximizing the proposed access energy efficiency, defined by the ratio of the sum achievable rate at the users to the overall consumed power, where the power consumption model includes the adaptive decoding power. The formulated problem is non-convex and generally NP-hard. To solve it, we first apply the high-complexity branch-and-bound algorithm to find the global optimal solution. Then, we develop a lower complexity algorithm which iteratively solves the convex approximated problem until convergence. Compared with the conventional methods, this algorithm converges faster to a solution that is very close to the global optimal solution achieved by the branch-and-bound approach. Finally, we exploit the framework of the alternating direction method of multipliers on the convex approximated problem to develop a distributed algorithm. Numerical results are obtained to show the improvement of our proposed model with much better power conservation compared with the different design of fixed circuit power assignment. Autors: Tri Minh Nguyen;Animesh Yadav;Wessam Ajib;Chadi Assi; Appeared in: IEEE Transactions on Wireless Communications Publication date: Jul 2017, volume: 16, issue:7, pages: 4711 - 4726 Publisher: IEEE
» CFVIE Formulation for EM Scattering on Inhomogeneous Anisotropic—Metallic Objects
 Abstract:The coupled-field volume integral equation-Dini series expansion (CFVIE-DSE) method is employed for electromagnetic scattering on inhomogeneous anisotropic-metallic objects. The anisotropic coating is both of gyroelectric and gyromagnetic type. Unlike traditional methods that describe the metallic core through a surface integral, a full-wave method is developed based on VIEs only, in conjunction with modified tensorial Green’s functions, taking into account the electric boundary condition (BC) on core’s perfect electric conducting surface. CFVIE-DSE is then solved using entire domain basis functions of Dini-type. New orthogonal sets in the domain of anisotropy are developed for the proper satisfaction of the physical BCs, along with the reduction of the CFVIE to algebraic form. The method is fully validated, and numerical results regarding radar cross section (RCS) computations for various anisotropic configurations are presented. Autors: Georgios D. Kolezas;Grigorios P. Zouros; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Jul 2017, volume: 65, issue:7, pages: 3788 - 3793 Publisher: IEEE
» Challenges for 5G?The Future of Wireless Communications [From the Guest Editor's Desk]
 Abstract:The articles in this special section focus on initiatives of various IEEE Societies to promote 5G technologies, with particular emphasis on architectures, systems, and evaluation procedures. Wireless communication networks and technologies are being pushed to their limits with ever-increasing user expectations for quality of service. To satisfy the emerging requirements for fifth-generation (5G) communications, various multi antenna-based network infrastructures are being considered. A number of IEEE Societies, including the IEEE Microwave Theory and Techniques Society community, are working diligently to develop various candidate technologies and architectures to enable efficient 5G deployments. All aspects of 5G communication-link ingredients—from devices, circuits, and system architectures to over-the-air (OTA) and channel measurements at microwave to millimeter-wave frequencies need to be addressed for successful 5G deployment. Autors: Debabani Choudhury; Appeared in: IEEE Microwave Magazine Publication date: Jul 2017, volume: 18, issue:5, pages: 16 - 16 Publisher: IEEE
» Change Detection in Polarimetric SAR Images Using a Geodesic Distance Between Scattering Mechanisms
 Abstract:A novel technique to generate the difference image (DI) in change detection analysis for polarimetric SAR (PolSAR) data is proposed. Unlike the standard methods, viz., band difference or intensity/amplitude ratioing, the proposed technique utilizes the full vector nature of multitemporal PolSAR data. In this data, a pixel is characterized by a Kennaugh matrix. The geodesic distance (GD) on an unit sphere is utilized to define the distance between the Kennaugh matrices of the three elementary targets (trihedral, dihedral, and 45° rotated dihedral about the radar line of sight) producing canonical scattering mechanisms and the observed Kennaugh matrix. Three absolute differences of the GD from respective elementary targets are obtained for time instants and . The DI is then the maximum among the three quantities. The proposed technique is applied to two scenes obtained from the L-band UAVSAR data characterizing changes due to urbanization. The principal component analysis with -means clustering proposed by Celik is used to obtain the binary change map. The proposed differencing method performs better than the single-channel intensity band ratio and the total power ratio for time instants and . The detection rate with the proposed technique is 6% and 20% better than the ratio methods for the two data sets, respectively, with the higher value as a measure - f performance evaluation. Autors: Debanshu Ratha;Shaunak De;Turgay Celik;Avik Bhattacharya; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Jul 2017, volume: 14, issue:7, pages: 1066 - 1070 Publisher: IEEE
» Channel Magnitude Based Energy Detection With Receive Diversity for Multi-Level Amplitude-Shift Keying in Rayleigh Fading
» Channel Mobility in GaN Hybrid MOS-HEMT Using SiO2 as Gate Insulator
 Abstract:The channel mobility in SiO2/GaN hybrid metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs) has been studied. The formalism used for the inversion mobility in MOSFETs has been adapted to the case of GaN MOS-HEMTs, which operate in accumulation condition. Using the values of interface trapped charges ( cm) and surface roughness (RMS = 0.15 nm) determined by capacitance-voltage measurements and nanoscale morphological analyses allowed to derive meaningful physical parameters for the mobility model. The temperature dependence of the peak mobility—that decreases from 110 cm at room temperature down to 91 cm at 423 K—is mainly ruled by phonon and Coulomb scattering effects. The implications in practical devices were discussed, considering the possible improvement of the device on-resistance that can be obtained by reducing the interfaces state density at the SiO2/GaN interface. Autors: Patrick Fiorenza;Giuseppe Greco;Ferdinando Iucolano;Alfonso Patti;Fabrizio Roccaforte; Appeared in: IEEE Transactions on Electron Devices Publication date: Jul 2017, volume: 64, issue:7, pages: 2893 - 2899 Publisher: IEEE
» Characteristics of Elevated-Metal Metal-Oxide Thin-Film Transistors Based on Indium-Tin-Zinc Oxide
 Abstract:Based on the distinct effects of oxidizing thermal annealing on the properties of zinc oxide and indium-gallium-zinc oxide (IGZO) under covers of different gas-permeabilities, the elevated-metal metal-oxide (EMMO) thin-film transistor (TFT) architecture has been proposed and demonstrated using IGZO as the channel material. However, the speculation that the EMMO architecture is more generally applicable to semiconducting metal oxides other than IGZO has yet to be verified. Presently reported is an EMMO TFT with a modified structure employing indium-tin-zinc oxide as the channel material. The resulting TFT exhibited good performance metrics: a relatively higher field-effect mobility of 23.2 ± 0.8 cm2/Vs, an ON/OFF current ratio of at least , a pseudo subthreshold slope of 165 ± 15 mV/decade, a width-normalized off-state current of at most , and robust stability against gate-bias stress. Autors: Zhihe Xia;Lei Lu;Jiapeng Li;Zhuoqun Feng;Sunbin Deng;Sisi Wang;Hoi Sing Kwok;Man Wong; Appeared in: IEEE Electron Device Letters Publication date: Jul 2017, volume: 38, issue:7, pages: 894 - 897 Publisher: IEEE

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