#### Electrical and Electronics Engineering publications abstract of: 09-2017 sorted by title, page: 9

» Inertia Emulation in AC/DC Interconnected Power Systems Using Derivative Technique Considering Frequency Measurement Effects
 Abstract:Virtual inertia is known as an inevitable part of the modern power systems with high penetration of renewable energy. Recent trend of research is oriented in different methods of emulating the inertia to increase the sustainability of the system. In the case of dynamic performance of power systems especially in Automatic Generation Control (AGC) issue, there are concerns considering the matter of virtual inertia. This paper proposes an approach for analyzing the dynamic effects of virtual inertia in two-area AC/DC interconnected AGC power systems. Derivative control technique is used for higher level control application of inertia emulation. This method of inertia emulation is developed for two-area AGC system, which is connected by parallel AC/DC transmission systems. Based on the proposed technique, the dynamic effect of inertia emulated by storage devices for frequency and active power control are evaluated. The effects of frequency measurement delay and phase-locked loop effect are also considered by introducing a second-order function. Simulations performed by MATLAB software demonstrate how virtual inertia emulation can effectively improve the performance of the power system. A detailed eigenvalue analysis is also performed to support the positive effects of the proposed method. Autors: Elyas Rakhshani;Pedro Rodriguez; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3338 - 3351 Publisher: IEEE
» Inference for Multicomponent Systems With Dependent Failures
 Abstract:Multicomponent systems may experience failures with correlations amongst failure times of groups of components, and some subsets of components may experience common cause, simultaneous failures. We present a novel, general approach to model construction and inference in multicomponent systems incorporating these correlations in an approach that is tractable even in very large systems. In our formulation, the system is viewed as being made up of independent overlapping subsystems (IOS). In these systems, components are grouped together into overlapping subsystems, and further into nonoverlapping subunits. Each subsystem has an independent failure process, and each component's failure time is the time of the earliest failure in all of the subunits of which it is a part. We apply this method to observations of an IOS model based on a multicomponent system accumulating damage due to a series of shocks, and with no repair/rectification actions. The model associates individual shock processes with each subsystem, and includes the Marshall–Olkin multivariate exponential model as a special case. We present approaches to simulation and to the estimation of the parameters of the model, given component failure data for various system configurations (series, parallel, and other arrangements). Autors: Richard Arnold;Stefanka Chukova;Yu Hayakawa; Appeared in: IEEE Transactions on Reliability Publication date: Sep 2017, volume: 66, issue:3, pages: 616 - 629 Publisher: IEEE
» Influence of Anatomical Detail and Tissue Conductivity Variations in Simulations of Multi-Contact Nerve Cuff Recordings
 Abstract:Accurate simulations of peripheral nerve recordings are needed to develop improved neuroprostheses. Previous models of peripheral nerves contained simplifications whose effects have not been investigated. We created a novel detailed finite element (FE) model of a peripheral nerve, and used it to carry out a sensitivity analysis of several model parameters. To construct the model, in vivo recordings were obtained in a rat sciatic nerve using an 8-channel nerve cuff electrode, after which the nerve was imaged using magnetic resonance imaging (MRI). The FE model was constructed based on the MRI data, and included progressive branching of the fascicles. Neural pathways were defined in the model for the tibial, peroneal and sural fascicles. The locations of these pathways were selected so as to maximize the correlations between the simulated and in vivo recordings. The sensitivity analysis showed that varying the conductivities of neural tissues had little influence on the ability of the model to reproduce the recording patterns obtained experimentally. On the other hand, the increased anatomical detail did substantially alter the recording patterns observed, demonstrating that incorporating fascicular branching is an important consideration in models of nerve cuff recordings. The model used in this study constitutes an improved simulation tool and can be used in the design of neural interfaces. Autors: Purbasha Garai;Ryan G. L. Koh;Martin Schuettler;Thomas Stieglitz;José Zariffa; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1653 - 1662 Publisher: IEEE
» Influence of Axial Magnetic Field on Cathode Plasma Jets in High-Current Vaccum Arc
 Abstract:The cathode plasma jets in vacuum arc and the effect of magnetic field on them have been studied for several years and these studies are helpful to understand the arc characteristics and improve the controlling effect of magnetic field on arc plasma. In this paper, the experiments of the cup-shaped axial magnetic field (AMF) contacts were conducted in which a Helmholtz coil was introduced to generate different external imposed AMFs. It was found that the appearance of arc plasma was changed by variation of the external imposed AMF. If the composite AMF in arc column increased gradually, the obvious individual cathode plasma jets were detected, the arc constriction decreased, and the arc stability increased. Meanwhile, the inclination of cathode plasma jets was observed and the inclination direction was found to be consistent with the magnetic field vector direction which is closely related to the composite AMF. By variation of the external imposed AMF and its direction, the inclination direction of cathode plasma jets also changed. The criterion to detect obvious cathode jets in arc column is obtained that at the contact peripheral where R> 80.5% R0 (R0 is the contact radius), the AMF strength is no less than 4.5 mT/kA. It was also found that if the composite AMF in interelectrode gap points to different directions at a certain moment, it may lead to the transfer of arc column from the center to the edge of the interelectrode region and the arc instability until when the composite AMF in the interelectrode gap points to the same direction. It can be concluded that the appearance of individual cathode plasma jets can be manipulated by the variation of AMF, which is helpful to study the interaction between arc plasma and electrodes, especially the anode, and improve the interruption performance at higher current. Autors: Dingge Yang;Shenli Jia;Weidong Qi;Jingfeng Wu;Sen Wang;Yanhua Han;Bin Ding;Heng Zhang;Wenhui Li; Appeared in: IEEE Transactions on Plasma Science Publication date: Sep 2017, volume: 45, issue:9, pages: 2596 - 2603 Publisher: IEEE
» Influence of Drain Doping Engineering on the Ambipolar Conduction and High-Frequency Performance of TFETs
 Abstract:In this paper, the effect of a proposed drain doping engineering on the ambipolar conduction and high-frequency performance of tunneling FETs (TFETs) is investigated using 2-D TCAD simulations. The proposed TFET structure is based on using a high-doped region above a low-doped region of the drain side. It is demonstrated that when splitting the drain into two regions, one with high doping above the other of low doping, the tunneling width at the channel–drain interface increases. This increase in the tunneling width causes an appreciable reduction of ambipolar current in the TFET. Moreover, high-frequency figures of merit regarding the transconductance (), source-to-gate and drain-to-gate capacitances, and unit-gain cutoff frequency () are analyzed. It is found that the combination of drain doping regions could enhance the high-frequency performance. Additionally, the proposed technique does not deteriorate the ON-current levels. Autors: Ahmed Shaker;Mona El Sabbagh;Mohammed M. El-Banna; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3541 - 3547 Publisher: IEEE
» Influence of Microscopic Electric Field Enhancement on Microparticle Impact Phenomena Based on Fractal Modeling
 Abstract:The objective of this paper is to study the influence of microscopic electric field enhancement caused by microprotrusions on microparticle impact phenomena based on fractal modeling. In this paper, microprotrusions with a radius of and heights 0, 1, 2, 5, and are considered, according to the height–width ratios 0, 0.2, 0.4, 1, and 2, respectively. The microparticles and contacts are assumed to be made of copper. The radius of the microparticle is assumed to be and the applied voltage is 60 kV. First, microprotrusions with different height–width ratios are modeled based on fractal theory. Then, the microscopic electric field distortions caused by microprotrusions on the contact surface are simulated based on fractal models of microprotrusions. The impact velocities of microparticles under different cases are calculated based on basic microparticle theories. Finally, the microparticle impact phenomena are simulated using the smoothed particle hydrodynamics method under the microscopic electric field caused by microprotrusions on the contact surface. The results show that the microscopic electric field enhancement caused by microprotrusions will have a significant influence on impact velocities, the characteristics of secondary particles, and the craters produced on the target contact surface. The results of this paper may provide some useful information to further understand the vacuum breakdown initiated by microparticles. Autors: Yingyao Zhang;Xinye Xu;Lijun Jin;Zhenlian An;Yingsan Geng;Jianhua Wang; Appeared in: IEEE Transactions on Plasma Science Publication date: Sep 2017, volume: 45, issue:9, pages: 2588 - 2595 Publisher: IEEE
» Infrastructure Circuits for Lifetime Improvement of Ultra-Low Power IoT Devices
 Abstract:An ultra-low power (ULP), energy-harvesting system-on-chip, that can operate in various application scenarios, is needed for enabling the trillions of Internet-of-Things (IoT) devices. However, energy from the ambient sources is little and system power consumption is high. Circuits and system development require an optimal use of available energy. In this paper, we present circuits that can improve the energy utilization in an IoT device by providing improvements at critical points of the flow of harvested energy. A boost converter circuit, that can harvest energy from 10-mV input voltage and a few nanowatt of input power, makes more harvested energy available for the IoT device. A single-inductor-multiple-output buck-boost converter provides high-efficiency and low-voltage power management solution to put most of the harvested energy for system use. A real time clock and ULP bandgap reference circuit significantly reduce the standby power consumption. The proposed ULP circuits are developed in 130-nm CMOS technology. The combined effects of these circuits and the system design technique can improve the life-time of an example IoT device by over four times in higher power consumption mode and over 70 times in ULP mode. Autors: Nasim Shafiee;Shikhar Tewari;Benton Calhoun;Aatmesh Shrivastava; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Sep 2017, volume: 64, issue:9, pages: 2598 - 2610 Publisher: IEEE
» Input Voltage Mapping Optimized for Resistive Memory-Based Deep Neural Network Hardware
 Abstract:Artificial neural network (ANN) computations based on graphics processing units (GPUs) consume high power. Resistive random-access memory (RRAM) has been gaining attention as a promising technology for implementing power-efficient ANNs, replacing GPU. However, nonlinear – characteristics of RRAM devices have been limiting its use for ANN implementation. In this letter, we propose a method and a circuit to address issues due to the nonlinear – characteristics. We demonstrate the feasibility of the method by simulating its application to multiple neural networks, from multi-layer perceptron to deep convolutional neural network based on a typical RRAM model. Results from classifying datasets including ImageNet show that the proposed method produces much higher accuracy than the naive linear mapping for a wide range of nonlinearity. Autors: Taesu Kim;Hyungjun Kim;Jinseok Kim;Jae-Joon Kim; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1228 - 1231 Publisher: IEEE
» Insights Into the Operation of Hyper-FET-Based Circuits
 Abstract:Devices combining transistors and phase transition materials are being investigated to obtain steep switching and a boost in the ratio and, thus, to solve power and energy limitations of CMOS technologies. This paper analyzes the operation of circuits built with these devices. In particular, we use a recently projected device called hyper-FET to simulate different circuits, and to analyze the impact of the degraded dc output voltage levels of hyper-FET logic gates on their circuit operation. Experiments have been carried out to evaluate power of these circuits and to compare with counterpart circuits using FinFETs. The estimated power advantages from device level analysis are also compared with the results of circuit level measurements. We show that these estimations can reduce, cancel, or even lead to power penalties in low switching and/or low-frequency circuits. We also discuss relationships with some device level parameters showing that circuit level considerations should be taken into account for device design. Autors: María J. Avedillo;Juan Núñez; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3912 - 3918 Publisher: IEEE
» Insights Into the Power-Off and Power-On Transient Performance of Power-Rail ESD Clamp Circuits
 Abstract:The power-off and power-on transient performance of power-rail electrostatic discharge (ESD) clamp circuits is investigated in this paper. In order to serve this purpose, the transient performance of a timed shutoff power-rail ESD clamp circuit in a 65-nm CMOS process is characterized by a three-terminal test method. Based on the characterization results, several insights are summarized: it is found that the bigFET response time of the investigated circuit is dependent on the pulse peak voltage. Besides, the resistor–capacitor network is verified to be a slew-rate detector instead of a rise-time detector. Moreover, the different bigFET response mechanisms under various power-on disturbances are clarified. In addition, the validity of these insights for other designs is also discussed in this paper. Autors: Guangyi Lu;Yuan Wang;Yize Wang;Xing Zhang; Appeared in: IEEE Transactions on Device and Materials Reliability Publication date: Sep 2017, volume: 17, issue:3, pages: 577 - 584 Publisher: IEEE
» Integrated Evaluation of Reliability and Stability of Power Systems
 Abstract:This paper investigates the impacts of transient instability on power system reliability. Traditionally, composite system reliability evaluation has been performed based on steady-state estimation of load curtailments; system dynamics have often been ignored, mostly due to computational complexity. In this paper, three probabilistic transient stability indices are proposed to assess system robustness against dynamic contingencies and to account for system instability in computing reliability indices. A direct method is utilized for transient stability assessment based on computing the energy margin of the system under fault events (energy margins measure the ability of a system to withstand contingencies). Energy margins along with the probability of occurrences of the events are used to update the probabilistic transient stability indices. The dependencies of reliability and stability indices on the fault clearing time are also evaluated. This method is applied on the reduced Western Electricity Coordinating Council and the New England 39 bus test systems. The results indicate the importance of considering the effect of stability in reliability evaluation. Autors: Mohammed Benidris;Joydeep Mitra;Chanan Singh; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 4131 - 4139 Publisher: IEEE
» Integrated Reciprocal Conversion With Selective Direct Operation for Energy Harvesting Systems
 Abstract:Energy harvesting IoT systems aim for energy neutrality, i.e., harvesting at least as much energy as is needed. This, however, is complicated by variations in environmental energy and application demands. Conventional systems use separate power converters to interface between the harvester and the storage, and then to the CPU system. Reciprocal power conversion has recently been proposed to perform both roles, eliminating redundancy and minimizing losses. This paper proposes to enhance this topology with “selective direct operation,” which completely bypasses the converter when appropriate. The integrated system, with 82% bidirectional conversion efficiency, was validated in 65-nm CMOS with only the harvester, battery, and decoupling capacitors being off-chip. Optimized for operation with cm2 photo-voltaic cell and a 32-b sub-threshold processor, the scheme enables up to 16% otherwise wasted energy to be utilized to provide >30% additional compute cycles under realistic indoor lighting conditions. Measured results show 84% peak conversion efficiency and energy neutral execution of benchmark sensor software (ULPBench) with cold-start capability. Autors: Anand Savanth;Alex S. Weddell;James Myers;David Flynn;Bashir M. Al-Hashimi; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Sep 2017, volume: 64, issue:9, pages: 2370 - 2379 Publisher: IEEE
» Integrated Transmission and Distribution System Power Flow and Dynamic Simulation Using Mixed Three-Sequence/Three-Phase Modeling
 Abstract:The interactions between distribution and transmission systems have increased significantly in recent years. However, in traditional power system simulation tools, transmission and distribution systems are separately modeled and analyzed. Hence, it is difficult to analyze the impacts of distribution systems on transmission systems and their interactions in detail. To facilitate the analysis of integrated transmission and distribution (T&D) systems, a novel modeling framework is proposed in this paper, where the transmission system is modeled as one subsystem in three-sequence detail, while each distribution system connected to it is represented as a subsystem and modeled in three-phase detail. With this modeling approach, unbalanced conditions at the boundary between T&D systems and within the transmission system can be represented. The integrated T&D power flow is solved by iteratively solving a three-sequence power flow for the transmission system and a three-phase power flow for each distribution system. Furthermore, a new dynamic simulation algorithm for integrated T&D system is proposed. The main challenge in developing this integrated T&D dynamic simulation is associated with different network representations in the transmission and distribution systems. With a partitioned solution approach adopted for dynamic simulation, the multi-area Thévenin equivalent approach is utilized in the network solution step to address this challenge. The proposed algorithms have been tested against an all electromagnetic transient simulation. Autors: Qiuhua Huang;Vijay Vittal; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3704 - 3714 Publisher: IEEE
» Integrating Ego, Homophily, and Structural Factors to Measure User Influence in Online Community
 Abstract:Research problem: In the current information age, people are increasingly accustomed to sharing their special interests online and are influenced by the relationships developed from that sharing. The purpose of this study was to better measure peer influence in these online communities. Research questions: 1. How can peer influence in online communities be measured in a way that comprehensively incorporates peer-based characteristics, the homophily effect, and the structural position of a user in the network? 2. Is the method proposed in this study superior to other existing methods? Literature review: Previous literature on measuring online user influence can be classified into two streams: 1. Those that focus on the intrinsic characteristics of social media players to measure peer influence; 2. Those that address social network structure. Relevant computing algorithms include Topic-Based PageRank, Quality-Structure index, and so on. Although the first stream considers afocal peer's intrinsic characteristics, it overlooks the interpeer attraction in terms of similarity and discrepant knowledge among peers. The second stream mostly stresses the structures of social networks to measure network-wide peer influence but underestimates the effect of interpeer attraction that may leverage every diffusion step of peer influence through the network. To fill this research gap, this study proposes a new method of measuring network user influence that incorporates peers' intrinsic factors, interpeer influence factors as homophily effect, and network structure. Homophily refers to the degree to which pairs of individuals who interact are similar with respect to certain attributes. Methodology: From the communication sender-receiver perspective, we developed a computable method that incorporates peer-based characteristics, the homophily effect, and the structural position of a user in the network to measure the social network user influence. Two empirical studies - ere subsequently conducted in a social network service-based online community and an online professional logistics community to verify the effectiveness of the proposed method. Results and conclusions: The empirical results show that our proposed method provides higher prediction accuracy of user influence rank in an online community than the other existing methods. These findings lay a foundation for future theoretical exploration and provide a useful tool for targeting influential users in online communities such as blogs, bulletin board systems, and forums. Autors: Chenghong Zhang;Tian Lu;Shoucong Chen;Cheng Zhang; Appeared in: IEEE Transactions on Professional Communication Publication date: Sep 2017, volume: 60, issue:3, pages: 292 - 305 Publisher: IEEE
» Integrating Poly-Silicon and InGaZnO Thin-Film Transistors for CMOS Inverters
 Abstract:The applications of a-InGaZnO thin-film transistors (TFTs) to logic circuits have been limited owing to the intrinsic n-channel operation. In this paper, we demonstrated a hybrid inverter constructed by p-channel low-temperature poly-silicon (LTPS) TFTs and n-channel amorphous-indium–gallium–zinc–oxide (a-IGZO) TFTs. Hydrogenated LTPS TFTs and a-IGZO TFTs have been successfully fabricated on the same panel, followed by a rapid thermal annealing treatment to remove the hydrogens in the a-IGZO TFTs. The resulted hybrid inverter exhibits large noise margin closed to and a high voltage gain as 68.3. Due to the complementary configurations in the static state, the inverter shows small current and thus consumes low power in hundreds of picowatts. As all the fabrication processes are compatible with conventional techniques, the reported results may open new opportunities in circuit design and applications for oxide TFTs. Autors: ChangDong Chen;Bo-Ru Yang;Chuan Liu;Xing-Yu Zhou;Yuan-Jun Hsu;Yuan-Chun Wu;Jang-Soon lm;Po-Yen Lu;Man Wong;Hoi-Sing Kwok;Han-Ping D. Shieh; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3668 - 3671 Publisher: IEEE
» Integrating Two Stages as a Common-Mode Transformerless Photovoltaic Converter
 Abstract:A single-phase common-mode transformerless grid-connected photovoltaic (PV) converter, which is based on the integration of two stages, is proposed in this paper. Transformer elimination in grid-connected PV systems has many advantages. It not only reduces cost, size, and weight but also increases the complete system efficiency. Since there is no galvanic isolation between grid and PV array, a leakage current may appear due to the PV parasitic capacitance to the ground, if this is not taken into account in the converter design. This paper presents a dc/dc boost converter integrated with a full-bridge inverter. The integration of these two stages reduces the ground leakage current. The neutral line of the grid is directly connected to the negative terminal of the PV array, eliminating any possibility of leakage current in this terminal. The principle of operation of the transformerless converter is analyzed, and a 200-W topology is experimentally tested. Autors: Nimrod Vázquez;Jeziel Vázquez;Joaquín Váquero;Claudia Hernández;Esli Vázquez;René Osorio; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7498 - 7507 Publisher: IEEE
» Integration of DC Microgrids as Virtual Synchronous Machines Into the AC Grid
 Abstract:A smart and autonomous integration concept for dc microgrids into the legacy ac grid is proposed based on the virtual synchronous machine (VSM) concept. It utilizes a dc–ac converter as a universal VSM-based interface (VSMBI) between the ac grid and various distributed energy resources (DER) connected on the dc side. The control strategy of it includes: 1) a frequency regulation improved from previous VSM works, which is suitable for the microgrid integration; 2) an improved dual droop control between the ac frequency and the dc side energy storages; 3) a power system stabilizer to enhance the system stability. Under this concept, the VSMBI integrates the DERs, loads and energy storages in the dc microgrid into a VSM. The VSMBI and the dc microgrid together will respond to short-term and long-term requirements of the grid frequency regulation, and achieve autonomous power management for the ac grid and the dc microgrid. It is therefore an important step forward in supporting high DER penetration. The concept, its design and small-signal analysis are presented in this paper. Its effectiveness and functions are verified by simulation and experimental results. Autors: Dong Chen;Yizhe Xu;Alex Q. Huang; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7455 - 7466 Publisher: IEEE
» Integration of Six-Phase EV Drivetrains Into Battery Charging Process With Direct Grid Connection
 Abstract:The paper proposes two novel topologies for integrated battery charging of electric vehicles. The integration is functional and manifests through re-utilization of existing propulsion drivetrain components, primarily a six-phase inverter and a six-phase machine, to serve as components of a fast (three-phase) charging system. An important feature of the proposed charging systems is that they are with direct grid connection, thus nonisolated from the mains. Torque is not produced in machines during the charging process. The paper provides a comprehensive evaluation of the novel systems, together with an existing topology. Various aspects of the considered chargers are detailed and elaborated, including current balancing, interleaving modulation strategy, and influence of rotor field pulsation on control and overall performance. A control strategy is proposed and the theory and control scheme are verified by experiments. Autors: Ivan Subotic;Nandor Bodo;Emil Levi; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 1012 - 1022 Publisher: IEEE
» Intercarrier Interference-Aware Pilot-Aided Channel Estimation in OFDM Systems
» Interface Electronics for Tactile Sensors Based on Piezoelectric Polymers
 Abstract:In this paper, we propose a novel design approach for the interface electronics of piezoelectric polymer tactile sensing systems. An interface electronics prototype based on commercial off-the-shelf (COTS) components having the same operating principle as the proposed approach has been fabricated. The system has been validated by using an experimental setup, where electrical and electromechanical characterization are carried out. The interface electronics measures charge of about 0.15 pC for applied forces as low as 12.5 mN at the working frequency of 27 Hz. The experimental average sensitivity of the system is 0.6 pC/kPa in the frequency range from 10 to 250 Hz. Long term goal is to miniaturize the interface electronics for the development of embedded tactile systems in prosthetic and robotic applications. Autors: Luigi Pinna;Ali Ibrahim;Maurizio Valle; Appeared in: IEEE Sensors Journal Publication date: Sep 2017, volume: 17, issue:18, pages: 5937 - 5947 Publisher: IEEE
» Interfacial Tuning for Detection of Cortisol in Sweat Using ZnO Thin Films on Flexible Substrates
 Abstract:We have demonstrated the detection of stress hormone cortisol from sweat using a flexible biosensing platform. Sweat-based detection faces many challenges such as stability of electrodes, sensitivity, and specificity. The surface states of zinc oxide (ZnO) can be leveraged for immobilizing various linker molecules for ultraspecific detection of biomolecules. In this study, we have used thiol-based linker molecule for binding to zinc terminations. We tested DSP from 5 to 100 mmol concentration in order to understand the effect of varying molarity on the electron transport properties of ZnO thin films. We performed electrochemical impedance spectroscopy measurements and Mott–Schottky analysis after incubation of the dispensed DSP linker on ZnO thin films. The optimized concentration of DSP was further incorporated in the immunoassay for detection of cortisol from 1 to 200 ng/mL spiked in sweat. Autors: Rujuta D. Munje;Sriram Muthukumar;Shalini Prasad; Appeared in: IEEE Transactions on Nanotechnology Publication date: Sep 2017, volume: 16, issue:5, pages: 832 - 836 Publisher: IEEE
» Interferences in Match Kernels
 Abstract:We consider the design of an image representation that embeds and aggregates a set of local descriptors into a single vector. Popular representations of this kind include the bag-of-visual-words, the Fisher vector and the VLAD. When two such image representations are compared with the dot-product, the image-to-image similarity can be interpreted as a match kernel. In match kernels, one has to deal with interference, i.e., with the fact that even if two descriptors are unrelated, their matching score may contribute to the overall similarity. We formalise this problem and propose two related solutions, both aimed at equalising the individual contributions of the local descriptors in the final representation. These methods modify the aggregation stage by including a set of per-descriptor weights. They differ by the objective function that is optimised to compute those weights. The first is a “democratisation” strategy that aims at equalising the relative importance of each descriptor in the set comparison metric. The second one involves equalising the match of a single descriptor to the aggregated vector. These concurrent methods give a substantial performance boost over the state of the art in image search with short or mid-size vectors, as demonstrated by our experiments on standard public image retrieval benchmarks. Autors: Naila Murray;Hervé Jégou;Florent Perronnin;Andrew Zisserman; Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence Publication date: Sep 2017, volume: 39, issue:9, pages: 1797 - 1810 Publisher: IEEE
» Interlaminar Magnetic Flux Assessment of a Transformer Core Measured by an Extra-Thin Printed Foil Detector
 Abstract:Transformer cores represent complex 3-D magnetization systems with balancing off-plane fluxes, normal to magnetization plane. Therefore, for optimizations of core performance, not only the information about the local induction distributions in the plane, but also perpendicular to it is highly essential. The conventional sensors for detections of off-plane inductions () are either of very high thicknesses, causing significant air gaps between laminations, or require extremely laborious preparations and are not reusable. In this paper, we developed an extra-thin (), reusable foil detector with handles for easy and precise insertion and positioning in the interior of a laminated core. The detector was assembled by a low-cost 3-D printer, equipped with a micro-dispersing system for printing of conductive ink, controlled by in-house developed software. The manufactured foil sensor, due to its high mechanical stability, enables detections of off-plane flux at many different locations within an entire core. The detector was effectively tested in a three-phase model transformer core, stacked from three packages of different width. The results prove the important role of sensor thickness for precise detection of off-plane induction. Peak induction increases in a strong non-linear way with increasing nominal magnetization . Maxima of arise close to border regions of packages. ceases for $B_{\mathrm{ NOM}}< 1.5$ T, favoring low level of audible noise. Autors: Georgi Shilyashki;Helmut Pfützner;Christian Huber; Appeared in: IEEE Transactions on Magnetics Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 6 Publisher: IEEE
» Intrinsic Contact Sensing for Touch Interface With Movable Structure
 Abstract:Intrinsic contact sensing is a method of using force sensors for separate tactile sensing without sensors arranged on the outer shell. Although the method is effective in some applications, the method has been limited to a fixed geometric shape. This study therefore proposes a method for movable structures. The contact position is estimated without geometric shape information by utilizing force/torque change over time. Additionally, this paper has proposed a method of eliminating the gravity term, which is a problem when using a structure-variable end effector as an interface. Calibration to decrease the calculation error was also introduced. Experimental evaluation using a wagon with drawers as the structure-variable object was done to verify the effectiveness of the proposed method. Autors: Toshiaki Tsuji;Tatsuki Seki;Sho Sakaino; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7342 - 7349 Publisher: IEEE
» Intrinsic speed limit of negative capacitance transistors
 Abstract:The emergence of negative capacitance as a way to limit power dissipation in CMOS logic transistors has raised the question of response delay of ferroelectric negative capacitance. Latency requirements for digital logic require a response time on the order of 10 ps or less. In this letter, we establish a coherent theoretical framework to analyze the delay between the clock edge at the gate and the response of the semiconductor channel in a ferroelectric negative capacitance transistor. The standard Landau–Khalatnikov equation approximates the slow, diffusive limit of the classical equation of motion. Therefore, using it to predict the response speed is unphysical. After extracting the damping and kinetic inductance from THz spectroscopy data, we simulate the full classical equation of motion and analyze the delay. We find that for doped hafnium oxides, the intrinsic delay is around 270 fs, far less than what is required for digital logic. Autors: Korok Chatterjee;Alexander John Rosner;Sayeef Salahuddin; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1328 - 1330 Publisher: IEEE
» Intrinsically Switchable Frequency Reconfigurable Barium Strontium Titanate Resonators and Filters
 Abstract:Multimode transceivers for the next generation of wireless devices require new and innovative frequency-agile microwave circuit designs to reduce their complexity, size, and cost. Intrinsically switchable frequency reconfigurable thin-film bulk acoustic resonators (FBARs) and filters that utilize these resonators are presented here for the very first time. Barium strontium titanate (BST) is a ferroelectric material that exhibits electric-field-induced piezoelectricity, which allows for the design of voltage controlled bulk acoustic wave devices. In this paper, a frequency reconfigurable resonator consisting of two series connected BST-based FBARs and a reconfigurable dual-band filter consisting of two 1.5 stage ladder-type bandpass filters are discussed. Their small size, simple design, and zero static power consumption make multifunctional ferroelectric thin-film devices attractive for use in adaptive and reconfigurable radios. Autors: Victor Lee;Seungku Lee;Seyit Ahmet Sis;Amir Mortazawi; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3221 - 3229 Publisher: IEEE
» Introducing a Novel Parallel Hole Collimator: The Theoretical and Monte Carlo Investigations
 Abstract:To assess function of various organs as well as recognize malignancy in its initial stages, single photon emission computed tomography system is employed in which the collimators can obtain the qualified images toward better diagnostic on the lesions and metabolic performance. Although new designs and optimized methods as well as the analytical models have been proposed to improve tradeoff between resolution and sensitivity in the collimators, but opposing behavior of them still remains as one of the major problems associated with the parallel hole collimators (PCs). In this paper, a new design, namely, extended parallel hole collimator (EPC) in which trapezoidal denticles are added upon the collimator septa at the detector side, has been proposed to improve performance of the PCs. Two PCs as PC35 and PC41 with hole sizes of 1.5 mm and hole lengths of 35 and 41 mm, respectively, are considered for comparison and investigation of the EPC performance. Theory and Monte Carlo simulations have been carried out to evaluate some of its related parameters such as sensitivity, resolution, and contrast. To reconstruct the tomographic images of Jaszczak phantom, the maximum-likelihood expectation maximization algorithm is chosen. The results have been indicated that the EPC has increased the amount of sensitivity as 10.2% compared to the PCs at the same resolution, and decreased the penetrating ratio as well as produced the tomographic images with lower noise coefficient (NC%), and improved contrast to noise ratio. Finally, it is found that the EPC may obtain the qualified images. Autors: Vahid Moslemi;Mansour Ashoor; Appeared in: IEEE Transactions on Nuclear Science Publication date: Sep 2017, volume: 64, issue:9, pages: 2578 - 2587 Publisher: IEEE
» Introduction to the IEEE Journal on Selected Topics in Signal Processing and IEEE Transactions on Signal and Information Processing Over Networks Joint Special Issue on Graph Signal Processing
 Abstract:The papers in this special issue are intended to address some of the main research challenges in Graph Signal Processing by presenting a collection of the latest advances in the domain. These papers examine key representation, learning and processing aspects for signals living on graphs and networks, as well as new methods and applications in graph signal processing. Numerous applications rely on the processing of high dimensional data that reside on irregular or otherwise unordered structures that are naturally modeled as networks. The need for new tools to process such data has led to the emergence of the field of graph signal processing, which merges algebraic and spectral graph theoretic concepts with computational harmonic analysis to process signals on structures such as graphs. This important new paradigm in signal processing research, coupled with its numerous applications in very different domains, has fueled the rapid development of an inter-disciplinary research community that has been working on theoretical aspects of graph signal processing and applications to diverse problems such as big data analysis, coding and compression of 3D point clouds, biological data processing, and brain network analysis. Autors: Pascal Frossard;Pier Luigi Dragotti;Antonio Ortega;Michael G. Rabbat;Alejandro Ribeiro; Appeared in: IEEE Journal of Selected Topics in Signal Processing Publication date: Sep 2017, volume: 11, issue:6, pages: 771 - 773 Publisher: IEEE
» Introduction to the Special Issue: 2016 IEEE International Ultrasonics Symposium
 Abstract:The 2016 IEEE International Ultrasonics Symposium was held in Tours, France, from September 18–21, 2016. Tours is in the heart of the French Chateau country and the Vinci Convention Center, a short walk from the Loire, provided an expansive venue for this conference. Sponsored by the IEEE Ultrasonics, Ferroelectrics, and Frequency Control Society, this symposium brings together technologists from academia, government labs, and industry to openly share their progress through posters, presentations, exhibits, short courses, and informal gatherings. The symposium strives for truly global representation and active involvement of students, early-career, and established practitioners. Autors: L. Scott Smith; Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Publication date: Sep 2017, volume: 64, issue:9, pages: 1274 - 1275 Publisher: IEEE
» Introduction to the Special Section on the 2016 IEEE BCTM and IEEE CSICS
 Abstract:This Special Section of the IEEE Journal of Solid-State Circuits presents the most interesting papers on integrated circuits from the 2016 IEEE Bipolar and BiCMOS Circuits and Technology Meeting (BCTM) and the 2016 IEEE Compound Semiconductor Integrated Circuits Symposium (CSICS) which cover the latest research on silicon-germanium and III-V integrated circuits and their use in state-of-the-art communication, radar, and imaging systems. Autors: Bodhisatwa Sadhu;Sorin P. Voinigescu; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Sep 2017, volume: 52, issue:9, pages: 2224 - 2225 Publisher: IEEE
» Inverse Feedback Shapers for Coupled Multibody Systems
 Abstract:The concept of inverse feedback shapers is fully developed in this report for the case of multibody systems with strongly coupled dynamics. The presented results constitute a nontrivial extension of the previous papers by the authors on input shaping focusing on effectively decoupled controlled and flexible parts. As the main technical result, the target mode for the inverse shaper design is identified based on an input–output transformation of the multibody system into the controlled subsystem, the attached residual oscillatory dynamics, and an internal feedback loop representing the dynamical coupling. A state feedback controller, applied for the selected generalized coordinate, is considered throughout this paper. Autors: Martin Hromčík;Tomáš Vyhlídal; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4804 - 4810 Publisher: IEEE
» Inverse Power Factor Droop Control for Decentralized Power Sharing in Series-Connected-Microconverters-Based Islanding Microgrids
 Abstract:Series-connected microconverters have been used to integrate distributed energy resources into grid mains through a single-stage power conversion. When this string converter is switched to islanding operation mode, it is preferred to share the local load demand by series microconverter modules in a decentralized manner. Due to the characteristics of series connection, the well-understood P–f droop and Q–E droop control for parallel distributed generation units in a conventional islanding microgrid is not applicable in this case. To solve this problem, the feasibility of using a simple power factor-frequency inverse droop control for series-connected islanding microconverters is discussed in this paper. The proposed method can achieve simultaneous real and reactive power sharing without the assistance of any communications between series microconverters. Furthermore, the accuracy of power sharing is not affected by the variations of microgrid feeder parameters or the disturbance of the point of common coupling (PCC) nonlinear loads. Simulated and experimental results are provided to verify the correctness of the proposed method. Autors: Jinwei He;Yunwei Li;Beihua Liang;Chengshan Wang; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7444 - 7454 Publisher: IEEE
» Investigating Applications in Health Care [Book\Software Reviews]
 Abstract:This book explains the multiple directions in which RF/microwave technologies are heading toward healthcare and biosensing applications, the achievements that have been made so far, and the challenges for researchers to solve in the near future. It consists of seven chapters by 15 authors, many of whom are active on the IEEE Microwave Theory and Techniques Society (MTT-S) Technical Coordinating Committee MTT-10, Biological Effects and Medical Applications. Apart from the first two chapters (which are tutorials on microwave technology and the dielectric properties of tissue), the book consists of five chapters that review different applications of RF/microwave energy to health care and biosensing. This book provides essential theories and solutions for the transmitter and receiver hardware block. The solutions offered are very practical for a circuit system designer. Whether the particular applications of RF/microwaves discussed in this volume will ever pass muster and enter the realm of evidence-based medicine remains to be seen. In their focus on the nuts and bolts of engineering, the authors of this otherwise meritorious volume are telling only a small part of the story about developing medical technology. Autors: Kenneth R. Foster; Appeared in: IEEE Microwave Magazine Publication date: Sep 2017, volume: 18, issue:6, pages: 126 - 127 Publisher: IEEE
» Investigation of an Electromagnetic Wearable Resonance Kinetic Energy Harvester With Ferrofluid
 Abstract:Human motion energy harvester can offer clean and continuous power, and therefore plays an important role in powering mobile devices, which suffer from short standby time because of the limited capability of the battery. In this paper, we investigate an electromagnetic resonance wearable kinetic energy harvester, which is comprised of an oscillator and a carbon fiber tube with two coils wound on its surface. The oscillator is comprised of a columnar PM connected to the two end covers with two elastic strings. The designed resonant frequency is 8–10 Hz, which is higher than the major frequency range of human motion (2–4 Hz), but it can absorb high frequency energy of impulse, such as footfall. Thus, the harvester can wear on legs to absorb the kinetic energy of footfall by resonance. The ferrofluid is adopted to decrease friction, which is one of the main challenges for improving efficiency of this type of energy harvester. The ferrofluid prevents the PM from touching the wall of the tube resulting in significant friction reduction. The FEM simulation results indicate that the ferrofluid can keep the vibrator (a permanent magnet) contactless even subjecting to ten times gravity acceleration. The maximum average output power of 9.5 mW is obtained with a total weight of 80.5 g when running at a speed of 10 km/h. A energy harvest circuit is carried out and an average power of 0.28 s can be stored. Autors: Shuai Wu;P. C. K. Luk;Chunfang Li;Xiangyu Zhao;Zongxia Jiao; Appeared in: IEEE Transactions on Magnetics Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 6 Publisher: IEEE
» Investigation of Anomalous Hysteresis in MOS Devices With ZrO2 Gate Dielectrics
 Abstract:Abnormal capacitance-voltage (CV) behavior is observed in metal-oxide semiconductor devices with zirconium oxide-gate dielectrics using a pulse CV technique. The relative positions of forward and reverse CV traces measured by the pulse technique are opposite those by conventional CV measurement. This unusual phenomenon is inconsistent with charge trapping and de-trapping, but may be mainly attributable to the interface dipoles at the high-/SiOx interface. This anomaly is sensitive to growth temperature as well as the post-deposition annealing process. Lower deposition temperature leads to more interface dipoles. However, after annealing in either nitrogen or forming gas ambient, the relative positions of forward and reverse CV curves measured by the pulse technique are consistent with those obtained by conventional CV measurement. Autors: Qifeng Lu;Yanfei Qi;Ce Zhou Zhao;Chenguang Liu;Chun Zhao;Stephen Taylor;Paul R. Chalker; Appeared in: IEEE Transactions on Device and Materials Reliability Publication date: Sep 2017, volume: 17, issue:3, pages: 526 - 530 Publisher: IEEE
» Investigation of Effects of Asymmetries on the Performance of Permanent Magnet Synchronous Machines
 Abstract:Asymmetries in permanent magnet synchronous machines (PMSM) can result from manufacturing tolerances or optimization techniques that deliberately introduce them on rotor, stator, or both. This paper analyzes the impact of such unbalance on the air gap pressure, that is radial and tangential to the direction of motion, by means of Maxwell Stress Tensor; also, their consequences on torque pulsations and unbalanced magnetic pulling. Neglecting the manufacturing variations in the analysis of high power density PMSMs underestimates the resultant torque ripple. Additionally, new vibration modes occur due to unbalanced radial pressure. On the other hand, a geometry optimized to minimize torque ripple through controlled asymmetry is investigated, the approach compensates harmonics in torque effectively, but such compensation does not have the same effect on radial forces. Finite element analysis and experimentation are used to support the analysis and it is found that an asymmetric PMSM with low torque ripple will not necessarily produce lower vibrations and noise. Autors: Alejandro J. Piña Ortega;Longya Xu; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 1002 - 1011 Publisher: IEEE
» Investigation of the Radio-Frequency Discharge in a High Current Negative Hydrogen Ion Source With a Global Enhanced Vibrational Kinetic Model
 Abstract:A numerical investigation of the radio-frequency hydrogen discharge in the high current negative hydrogen ion source (HCNHIS) is presented using a global enhanced vibrational kinetic model (GEVKM). The HCNHIS consists of a high-pressure (2–65 torr) radio-frequency discharge chamber where the main production of high-lying vibrational states of the hydrogen molecules occurs. The hydrogen plasma flow in the discharge chamber is reduced by a series of bypass tubes and enters through a nozzle into a low-pressure (1–15 mtorr) negative hydrogen ion production chamber where H− are generated mainly by the dissociative attachment of low-energy electrons to rovibrationally excited hydrogen molecules. The GEVKM is applied to the HCNHIS discharge and involves volume-averaged equations for 21 hydrogen species (atoms, ions, and molecules in excited states) and electrons. The GEVKM is supplemented with outlet boundary conditions for the nozzle and bypass tubes of the HCNHIS and accounts for compressibility, viscous, and rarefaction effects. GEVKM simulations of the RF discharge are performed with inlet flow rates of 5–1000 sccm and absorbed powers of 200–1000 W using the HCNHIS-2 design which is configured with an extractor grid attached to a short negative ion production region. These simulations investigate the effects of the absorbed power and the inlet flow rate on the chemical composition, electron and heavy particles temperature, wall temperature, the maximum extractable H− current in the discharge chamber, as well as optimum operational parameters of HCNHIS-2. GEVKM simulations of the HCNHIS-2 discharge are used to obtain estimates of the H− current and compared with Faraday cup measurements taken at the extraction grid. Autors: Sergey N. Averkin;Nikolaos A. Gatsonis;Lynn Olson; Appeared in: IEEE Transactions on Plasma Science Publication date: Sep 2017, volume: 45, issue:9, pages: 2460 - 2471 Publisher: IEEE
» Investigation on Economic and Reliable Operation of Meshed MTDC/AC Grid as Impacted by Offshore Wind Farms
 Abstract:The influence of complementarity balancing connected grid and control of offshore wind power generation on the economic and reliable operation of hybrid multiterminal HVDC (MTDC) and AC power system is investigated in the paper. The variances of distribution curve of both transmission loss of AC/DC system and voltage of critical nodes assessed by cumulant-based method are used to demonstrate how the different complementarity conditions, generation balancing strategies, MTDC grid topologies, and control schemes affect power system operation. In this paper, a study case of 16-generator 68-bus power system connected with three offshore wind farms is presented. The variance indices of transmission loss and voltage magnitude are calculated and then compared under different complementarity levels, active power balancing strategies, HVDC transmission systems, and controls, respectively. The analysis reveals that higher complementarity and multi-machine balancing strategy can effectively reduce system operational cost and enhance operational reliability. Compared to the point-to-point topology, the control pattern and parameter setting of multi-terminal topology are two key factors to determine its impact on system operation. Autors: S. Q. Bu;W. Du;H. F. Wang;Y. Liu;X. Liu; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3901 - 3911 Publisher: IEEE
» Investigation on Low Voltage Operation of Electrovibration Display
 Abstract:This paper presents three methods of input voltage signals that allow low voltage operation of an electrovibration display while preserving the perceptual feel and strength of electrovibration stimuli. The first method uses the amplitude modulation of a high-frequency carrier-signal. The second method uses a dc-offset, and the third method uses a combination of the two methods. The performance of the three methods was evaluated by a physical experiment that measured and analyzed static (dc-component) and dynamic (vibratory component) friction forces and two subsequent psychophysical studies. The physical experiment showed that only the dc -offset method enabled a statistically significant increase in the static friction force between the fingertip and the surface of the electrovibration display. The static friction increase was closely related to the root mean square of input voltage level. In contrast, all of the three methods increased the dynamic friction force significantly, which was deemed to be related to the high frequency effect validated in the previous literature. The first psychophysical study showed that the three proposed methods can significantly reduce the peak-to-peak (p-p) amplitude of an input voltage signal while generating perceptually equally strong electrovibrations to that produced by the conventional method. Using lower p-p voltage has the merits of a simpler electrical circuit and less electromagnetic noise, saving the overall system cost. Further, the perceived intensity of electrovibration was more correlated to the dynamic friction force than the static friction force. The second psychophysical study was a discrimination experiment, and it demonstrated that all the three proposed methods and the conventional method can provide perceptually similar stimuli despite their different signal forms and voltage amplitudes. Our experimental investigation allowed us to conclude that the d- -offset method is the best way to lower the driving voltage of an electrovibration display while providing perceptually equivalent electrovibrations. Autors: Jeonggoo Kang;Heewon Kim;Seungmoon Choi;Ki-Duk Kim;Jeha Ryu; Appeared in: IEEE Transactions on Haptics Publication date: Sep 2017, volume: 10, issue:3, pages: 371 - 381 Publisher: IEEE
» Investigation on Passive Booster for Improving Magnetic Coupling of Metal Mounted Proximity Range HF RFIDs
 Abstract:In this paper, the design methodology, fabrication, and measurement of a passive circuit for increasing the read range of the near-field-communications (NFCs) gadget in handheld devices to read miniature metal mounted radio-frequency identification (RFID) are discussed. Since, the impedances at source and load are unknown, the conventional methods are not helpful for designing a proper communication. The proposed circuit is fabricated on thin flexible polyimide film hence; it can be simply attached to the back of handheld devices with arbitrary shape. Having only one discrete component in the circuit is another step toward low-cost devices. The magnetic coupling between the small metal mounted high-frequency (HF) RFID and the NFC coil are improved by adding two coils connected in parallel to each other resonating at 13.56 MHz. One coil is designed to be coupled to the NFC coil and the other one to the HF RFID. The operability of the system is investigated not only by standard measurement equipment like vector network analyzer but also utilizing different smartphones. The agreement between the simulation and practical results shows that the booster improves the read range significantly. Autors: Hossein Saghlatoon;Rashid Mirzavand;Mohammad Mahdi Honari;Pedram Mousavi; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3401 - 3408 Publisher: IEEE
» Investigation on Self-Adjust Conductivity Modulation SOI-LIGBT Structure (SCM-LIGBT) for Monolithic High-Voltage IC
 Abstract:A novel composite device structure named self-adjust conductivity modulation lateral insulated gate bipolar transistor (SCM-LIGBT), including normal LIGBT region (NLT region), the EM-nMOS region (ENM region), and the series diode region (DIO region), is proposed in this paper. By adding the enhanced-mode nMOS region and the series diodes region, the parasitic NPN transistor (NPN) bipolar structure in the normal LIGBT structure can be triggered in on-state and the conductivity modulation is dramatically enhanced, which leads to the improvement on the current capability and the forward voltage. In addition, due to the base voltage of the parasitic NPN bipolar structure in the proposed device can be clamped at the forward threshold of the series diodes, therefore the latch-up issues can be immunized to guarantee the forward-biased safe operating area. Numerous simulations and measurements are presented to investigate the electrical characteristics of the proposed structure. The length of the fabrication SCM-LIGBT is , and the width of the DIO and NLT is 830 , while the width of the ENM is . The results demonstrate that the proposed SCM-LIGBT achieves a high-current capability ( of 2428 A/cm2 at V, a low on-state voltage drop of 1.15 V at A/cm2 with its breakdown voltage of 590 V. Autors: Weifeng Sun;Zhuo Yang;Jing Zhu;Fangjuan Bian;Siyang Liu;Jian Chen; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3762 - 3767 Publisher: IEEE
» Investigation on the Worst Read Scenario of a ReRAM Crossbar Array
 Abstract:This paper disproves the worst read scenario of a ReRAM crossbar array. If the previously believed worst read scenario is not the worst one, the read margin evaluated based on the scenario can be incorrect. We explored for read scenario worse than the previously believed worst scenario by wisely sampling scenarios and iteratively searching for the worse one. In experiment, our algorithm successfully found the scenario worse than the previously believed one, disproving the previously believed worst read scenario. Our results show that the sensing window estimated by the incorrect previously believed worst scenario is 14 times as large as the estimation by the worst scenario found by our algorithm. Autors: Yelim Youn;Kwangmin Kim;Jae-Yoon Sim;Hong-June Park;Byungsub Kim; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Sep 2017, volume: 25, issue:9, pages: 2402 - 2410 Publisher: IEEE
» Investigations of the Influence of PMSM Parameter Variations in Optimal Stator Current Design for Torque Ripple Minimization
 Abstract:Optimal stator current design has been widely investigated for torque ripple minimization of permanent magnet synchronous machines (PMSMs). The optimal current design requires accurate machine parameters including the permanent magnet flux and dq-axis inductances, which are varying during machine operation due to machine uncertainty. Therefore, this paper investigates how these machine parameter variations influence the optimal stator current design, and hence the torque ripple minimization performance. At first, torque ripple model-based analytical solution for optimal current design is introduced in this paper, which can theoretically reduce the torque ripple to zero. Then, machine parameter variations of a laboratory interior PMSM are tested and analyzed. It is found that the magnet flux under no load can be reduced by more than 10% from room temperature to the maximal operation temperature, and the inductance term (- ) can be reduced by more than 50% from no load to full load. Afterwards, analytical equations are derived to quantify the resultant torque ripples due to the variations of magnet flux, dq-axis inductances, and the cogging torque. Finally, the numerical and experimental studies are conducted to investigate the resultant torque ripples under different percentages of parameter variations. Autors: Chunyan Lai;Guodong Feng;Kaushik Mukherjee;Narayan C. Kar; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 1052 - 1062 Publisher: IEEE
» Iron Losses Calculation of an Axial Flux Machine Based on Three-Dimensional FEA Results Corresponding to One-Sixth Electrical Period
 Abstract:This paper describes the iron losses calculation of an axial flux machine with yokeless and segmented armature structure based on the limited three-dimensional (3-D) finite element analysis (FEA) results corresponding to one-sixth electrical period. Considering, the 3-D magnetic flux in both stator segments and rotor yoke, soft magnetic composites are used to manufacture the soft magnetic components. Furthermore, time-consuming 3-D FEA is necessary to evaluate the performance of the machine accurately. Due to the magnetic periodicity, most of the characteristics of the machine can be easily determined through averaging the limited 3-D FEA results. However, in some models the calculation of iron losses requires always the flux density waveform in each soft magnetic composites (SMC) element of the FEA model for an entire electrical period, especially when the losses resulted by minor loops should also be taken into account. Therefore, a general method to reconstruct the complete flux density waveform in each SMC component of the FEA model based on limited 3-D FEA results is suggested in this paper. Subsequently, the iron losses can be calculated with various models in time or frequency domain. Finally, the suggested method is validated by comprising the measurement of a prototype with the calculated iron losses based on the classical Bertotti formula. Autors: B. Zhang;M. Doppelbauer; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 1023 - 1030 Publisher: IEEE
» Irregular Phased Array Tiling by Means of Analytic Schemata-Driven Optimization
 Abstract:The design of subarrayed planar phased arrays characterized by an irregular organization of domino-shaped tiles is addressed. Starting from optimal tiling theorems drawn from mathematical theory, an enumerative approach able to retrieve the optimal clustering providing the maximum aperture coverage and the best radiation performance is proposed to deal with the synthesis of low-/medium-size rectangular arrays. Based on the same optimal theorems and still exploiting the algorithmic procedures at the basis of the enumerative approach, an innovative schemata-based optimization method is introduced for designing large arrays, as well. A set of representative results, concerned with ideal as well as real radiating elements, is reported and discussed to highlight the features and the potentialities of the proposed analytically based design framework. Autors: Nicola Anselmi;Paolo Rocca;Marco Salucci;Andrea Massa; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4495 - 4510 Publisher: IEEE
» Is it time to become a blockchain developer? [Resources_Careers]
 Abstract:Blockchains-the cryptographically assured ledgers at the heart of cryptocurrencies like Bitcoin-have been suggested as a platform for all kinds of financial instruments. But has the technology matured to the point where there's a significant market for developers who specialize in building on a blockchain? Signs suggest yes, based on what I saw and heard when hundreds of financiers, Wall Street analysts, and C-suite executives gathered in New York City in June. They were there to peer into the future of finance at the CB Insights' Future of Fintech conference, including what role blockchains might play. Autors: Amy Nordrum; Appeared in: IEEE Spectrum Publication date: Sep 2017, volume: 54, issue:9, pages: 21 - 21 Publisher: IEEE
» Iterative Detection With Amplitude-Phase Demodulator For Dual-Stream CE-OFDM
 Abstract:Dual-stream constant envelope orthogonal frequency division multiplexing (CE-OFDM) is a flexible waveform that can achieve low peak-to-average power ratio and high spectral efficiency. In this letter, a receiver with iterative detection based on amplitude-phase demodulator is proposed for the demodulation of the dual-stream CE-OFDM. Simulation results show that iterative detection with amplitude-phase demodulator outperforms the existing receiver for dual-stream CE-OFDM, especially for high phase-modulation index and high-order modulation constellation. Autors: Gaofeng Cui;Cheng Wang;Weidong Wang; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 2001 - 2004 Publisher: IEEE
» Iterative Frequency-Domain Joint Channel Estimation and Data Detection of Faster-Than-Nyquist Signaling
 Abstract:In this paper, we propose semi-blind iterative frequency domain joint channel estimation (CE) and data detection (DD) of faster-than-Nyquist signaling (FTNS). The proposed scheme achieves low-complexity operation, while maintaining a performance close to that of the perfect channel state information scenario. More specifically, we derive low-complexity frequency-domain CE for the faster-than-Nyquist pilot (FTNP) transmission scenario, where the symbol duration of a pilot block is lower than the Nyquist-criterion-based pilot transmission. Moreover, we propose a serially concatenated channel-encoded FTNS transceiver that takes into account FTNS-specific colored noise effects. The proposed low-complexity receiver carries out soft-decision frequency-domain equalization with the aid of the minimum-mean square error criterion while whitening the colored noise. As explicit benefits of the proposed frequency-domain CE for the FTNP, the demodulated FTNS data block can also be used as a long pilot block, so the iterative joint CE and DD becomes realistic. Simulation results demonstrate that the proposed two-stage-concatenated FTNS system relying on binary phase-shift keying-based FTNP and FTNS-data symbols achieves a better error-ratio performance than previous systems that do not consider colored noise effects in the high-symbol-packing FTNS regime. Autors: Takumi Ishihara;Shinya Sugiura; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 6221 - 6231 Publisher: IEEE
» Joint Channel Estimation and Impulsive Noise Mitigation in Underwater Acoustic OFDM Communication Systems
 Abstract:Impulsive noise occurs frequently in underwater acoustic (UA) channels and can significantly degrade the performance of UA orthogonal frequency-division multiplexing (OFDM) systems. In this paper, we propose two novel compressed sensing based algorithms for joint channel estimation and impulsive noise mitigation in UA OFDM systems. The first algorithm jointly estimates the channel impulse response and the impulsive noise by utilizing pilot subcarriers. The estimated impulsive noise is then converted to the time domain and removed from the received signals. We show that this algorithm reduces the system bit-error-rate through improved channel estimation and impulsive noise mitigation. In the second proposed algorithm, a joint estimation of the channel impulse response and the impulsive noise is performed by exploiting the initially detected data. Then, the estimated impulsive noise is removed from the received signals. The proposed algorithms are evaluated and compared with existing methods through numerical simulations and on real data collected during a UA communication experiment conducted in the estuary of the Swan River, WA, Australia, during December 2015. The results show that the proposed approaches consistently improve the accuracy of channel estimation and the performance of impulsive noise mitigation in UA OFDM communication systems. Autors: Peng Chen;Yue Rong;Sven Nordholm;Zhiqiang He;Alexander J. Duncan; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 6165 - 6178 Publisher: IEEE
» Joint Load Balancing and Interference Mitigation in 5G Heterogeneous Networks
 Abstract:We study the problem of joint load balancing and interference mitigation in heterogeneous networks in which massive multiple-input multiple-output macro cell base station (BS) equipped with a large number of antennas, overlaid with wireless self-backhauled small cells (SCs), is assumed. Self-backhauled SC BSs with full-duplex communication employing regular antenna arrays serve both macro users and SC users by using the wireless backhaul from macro BS in the same frequency band. We formulate the joint load balancing and interference mitigation problem as a network utility maximization subject to wireless backhaul constraints. Subsequently, leveraging the framework of stochastic optimization, the problem is decoupled into dynamic scheduling of macro cell users, backhaul provisioning of SCs, and offloading macro cell users to SCs as a function of interference and backhaul links. Via numerical results, we show the performance gains of our proposed framework under the impact of SCs density, number of BS antennas, and transmit power levels at low and high frequency bands. It is shown that our proposed approach achieves a 5.6 times gain in terms of cell-edge performance as compared with the closed-access baseline in ultra-dense networks with 350 SC BSs per . Autors: Trung Kien Vu;Mehdi Bennis;Sumudu Samarakoon;Mérouane Debbah;Matti Latva-aho; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 6032 - 6046 Publisher: IEEE
» Joint Scheduling and Transmission Power Control in Wireless Ad Hoc Networks
 Abstract:In this paper, we study how to determine concurrent transmissions and the transmission power level of each link to maximize the spectrum efficiency and minimize energy consumption in a wireless ad hoc network. The optimal joint transmission packet scheduling and power control strategy is determined when the node density goes to infinity and the network area is unbounded. Based on the asymptotic analysis, we determine the fundamental capacity limits of a wireless network, subject to an energy consumption constraint. We propose a scheduling and transmission power control mechanism to approach the optimal solution to maximize spectrum and energy efficiencies in a practical network. The distributed implementation of the proposed scheduling and transmission power control scheme is presented based on our medium access control (MAC) framework proposed by Rahimi Malekshan. Simulation results demonstrate that the proposed scheme achieves 40% higher throughput than the existing schemes. In addition, the energy consumption using the proposed scheme is about 20% of the energy consumed using existing power saving MAC protocols. Autors: Kamal Rahimi Malekshan;Weihua Zhuang; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 5982 - 5993 Publisher: IEEE
» Joint State Estimation and Delay Identification for Nonlinear Systems With Delayed Measurements
 Abstract:The problem of state estimation for nonlinear systems with unknown state or measurement delays is still an open problem. In this paper, we consider the case of measurement delay and propose an approach that combines a delay identifier with a suitable high-gain observer in order to achieve simultaneous estimation of state and delay. We provide sufficient conditions that guarantee the exponential convergence to zero of the errors, globally with respect to the system variables and locally with respect to the delay estimation. We validate the method through an example concerning population models. Autors: Filippo Cacace;Francesco Conte;Alfredo Germani;Giovanni Palombo; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4848 - 4854 Publisher: IEEE
» Joint Traffic Scheduling and Resource Allocations for Traffic Offloading With Secrecy Provisioning
» Joint Transceiver Design for Full-Duplex Cloud Radio Access Networks With SWIPT
» Joint Transceiver Design for Secure Downlink Communications Over an Amplify-and-Forward MIMO Relay
 Abstract:This paper addresses joint transceiver design for secure downlink communications over a multiple-input multiple-output relay system in the presence of multiple legitimate users and malicious eavesdroppers. Specifically, we jointly optimize the base station (BS) beamforming matrix, the relay station (RS) amplify-and-forward transformation matrix, and the covariance matrix of artificial noise, so as to maximize the system worst-case secrecy rate in the presence of the colluding eavesdroppers under power constraints at the BS and the RS, as well as quality of service constraints for the legitimate users. This problem is very challenging due to the highly coupled design variables in the objective function and constraints. By adopting a series of transformation, we first derive an equivalent problem that is more tractable than the original one. Then, we propose and fully develop a novel algorithm based on the penalty concave-convex procedure (penalty-CCCP) to solve the equivalent problem, where the difficult coupled constraint is penalized into the objective and the resulting nonconvex problem is solved at each iteration by resorting to the CCCP method. It is shown that the proposed joint transceiver design algorithm converges to a stationary solution of the original problem. Finally, our simulation results reveal that the proposed algorithm achieves better performance than other recently proposed transceiver designs. Autors: Yunlong Cai;Qingjiang Shi;Benoit Champagne;Geoffrey Ye Li; Appeared in: IEEE Transactions on Communications Publication date: Sep 2017, volume: 65, issue:9, pages: 3691 - 3704 Publisher: IEEE
» Joint Transceiver Design With Antenna Selection for Large-Scale MU-MIMO mmWave Systems
 Abstract:This paper considers the uplink of large-scale multiple-user multiple-input multiple-output millimeter wave systems, where several mobile stations (MSs) communicate with a single base station (BS) equipped with a large-scale antenna array, for application to fifth generation wireless networks. Within this context, the use of hybrid transceivers along with antenna selection can significantly reduce the implementation cost and energy consumption of analog phase shifters and low-noise amplifiers. We aim to jointly design the MS beamforming vectors, the hybrid receiving matrices (baseband and analog), and the antenna selection matrix at the BS in order to maximize the achievable system sum-rate under a set of constraints. The corresponding optimization problem is nonconvex and difficult to solve, mainly due to the receive antenna selection and constant modulus constraints on the analog receiving matrix. By exploiting the special structure of the problem and linear relaxation, we first convert this problem into three subproblems, which are solved via an alternating optimization method. The latter iteratively updates the antenna selection matrix, the transmit beamforming vectors, and the hybrid receiving matrices by sequentially addressing each subproblem while keeping the other variables fixed. Specifically, the antenna selection matrix is optimized via the concave–convex procedure; the weighted mean-square error minimization approach is used to find the solution for the transmit beamformer; and the hybrid receiver is obtained via manifold optimization. The convergence of the proposed algorithm is analyzed and its effectiveness is verified by simulation. Autors: Xiongfei Zhai;Yunlong Cai;Qingjiang Shi;Minjian Zhao;Geoffrey Ye Li;Benoit Champagne; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Sep 2017, volume: 35, issue:9, pages: 2085 - 2096 Publisher: IEEE
» Joint Uplink Base Station Association and Power Control for Small-Cell Networks With Non-Orthogonal Multiple Access
 Abstract:Since non-orthogonal multiple access (NOMA) with successive interference cancellation (SIC) can achieve superior spectral-efficiency and energy-efficiency, the concept of SCN using NOMA with SIC is proposed in this paper. Due to the difference in small-cell base stations’ locations, each mobile user perceives different channel gains to different small-cell base stations. Therefore, it is important to associate a mobile user with the right base station and control its transmit power for the uplink SCN using NOMA with SIC. However, the already-challenging base station association problem is further complicated by the need of transmit power control, which is an essential component to manage co-channel interference. Despite its importance, the joint base station association and power control optimization problem that maximizes the system-wide utility and at the same time minimizes the total transmit power consumption for the maximum utility has remained largely unsolved for the uplink SCN using NOMA with SIC, mainly due to its non-convex and combinatorial nature. To solve this problem, we first present a formulation transformation that captures two interactive objectives simultaneously. Then, we propose a novel algorithm to solve the equivalently transformed optimization problem based on the coalition formation game theory and the primal decomposition theory in the framework of simulated annealing. Finally, theoretical analysis and simulation results are provided to demonstrate that the proposed algorithm is guaranteed to converge to the global optimal solution in polynomial time. Autors: Li Ping Qian;Yuan Wu;Haibo Zhou;Xuemin Shen; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 5567 - 5582 Publisher: IEEE
» Joint Wideband Interference Suppression and SAR Signal Recovery Based on Sparse Representations
 Abstract:The problem of synthetic aperture radar image recovery in the presence of wideband interference (WBI) is investigated. Delayed versions of a transmitted signal are utilized to construct a dictionary in which a signal of interest (SOI) has a sparse representation. In this letter, WBI is sparsely represented by the time-frequency domain. By utilizing the transform domains, a joint estimation approach is devised to simultaneously perform WBI suppression and SOI recovery within an optimization framework. Based on the separability property in the optimization, an alternating direction method of multipliers-based approach is developed to efficiently obtain a solution. Finally, simulation results are presented to demonstrate the superior performance of the joint estimation algorithm. Autors: Hongqing Liu;Dong Li;Yi Zhou;Trieu-Kien Truong; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1542 - 1546 Publisher: IEEE
» Joint Wireless Positioning and Emitter Identification in DVB-T Single Frequency Networks
 Abstract:Digital television (DTV) signal has been recognized as a promising signal for navigation and positioning. However, due to the single frequency network (SFN) transmission within the European standard digital video broadcasting terrestrial (DVB-T) system, emitter confusion problem occurs in navigation and positioning, resulting in that a receiver is unable to know from which emitter a received signal comes. In this paper, we consider the wireless positioning with emitter confusion problem in DVB-T SFN networks. A joint wireless positioning and emitter identification algorithm is proposed, which is based on the expectation maximization (EM) method. The proposed algorithm is tested in a scenario, where signals are received from three to five emitters. Simulation results show that, relying on more than three emitters used in the tests for 2-D positioning, the EM-assisted positioning algorithm is feasible to achieve accurate positioning results in the existence of the emitter confusion problem. Our studies show that the performance achieved by the proposed algorithm approaches the Cramér-Rao bound. Furthermore, the proposed algorithm is effective to identify the DTV emitters, and the positioning performance is robust to the emitter identification error. Additionally, our methodology is general, and can be employed for time of arrival-based positioning in any SFNs. Autors: Liang Chen;Lie-Liang Yang;Jun Yan;Ruizhi Chen; Appeared in: IEEE Transactions on Broadcasting Publication date: Sep 2017, volume: 63, issue:3, pages: 577 - 582 Publisher: IEEE
» Ka-Band Characterization of Binder Jetting for 3-D Printing of Metallic Rectangular Waveguide Circuits and Antennas
 Abstract:The performance of additive manufactured (AM) RF circuits and antennas is continuously improving, and in some cases these AM components are comparable to state-of-the-art circuits made with traditional manufacturing techniques. Medium to high-power waveguides made with AM methods such as copper-plated plastics, selective laser melting (SLM), and copper additive manufacturing (3-D CAM) have shown good performance up to terahertz frequencies. In this paper, binder jetting (BJ) metal printing is characterized using electron beam microscopy [scanning electron microscopy (SEM)] and energy dispersive spectroscopy. The RF performance of the 3-D-printed circuits is benchmarked with Ka-band cavity resonators, waveguide sections, and a filter. An unloaded resonator of 616 is achieved, and the average attenuation of the WR-28 waveguide section is 4.3 dB/m. The BJ technology is tested with a meshed parabolic reflector antenna, where the illuminating horn, waveguide feed, and a filter are printed in a single piece. The antenna shows a peak gain of 24.56 dBi at 35 GHz. Autors: Eduardo A. Rojas-Nastrucci;Justin T. Nussbaum;Nathan B. Crane;Thomas M. Weller; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3099 - 3108 Publisher: IEEE
» Kernel-Based Reconstruction of Space-Time Functions on Dynamic Graphs
 Abstract:Graph-based methods pervade the inference toolkits of numerous disciplines including sociology, biology, neuroscience, physics, chemistry, and engineering. A challenging problem encountered in this context pertains to determining the attributes of a set of vertices given those of another subset at possibly diffe-rent time instants. Leveraging spatiotemporal dynamics can drastically reduce the number of observed vertices, and hence the sampling cost. Alleviating the limited flexibility of the existing approaches, the present paper broadens the kernel-based graph function estimation framework to reconstruct time-evolving functions over possibly time-evolving topologies. This approach inherits the versatility and generality of kernel-based methods, for which no knowledge on distributions or second-order statistics is required. Systematic guidelines are provided to construct two families of space-time kernels with complementary strengths: the first facilitates judicious control of regularization on a space-time frequency plane, whereas the second accommodates time-varying topologies. Batch and online estimators are also put forth. The latter comprise a novel kernel Kalman filter, developed to reconstruct space-time functions at affordable computational cost. Numerical tests with real datasets corroborate the merits of the proposed methods relative to competing alternatives. Autors: Daniel Romero;Vassilis N. Ioannidis;Georgios B. Giannakis; Appeared in: IEEE Journal of Selected Topics in Signal Processing Publication date: Sep 2017, volume: 11, issue:6, pages: 856 - 869 Publisher: IEEE
» Key Technologies for Next-Generation Digital RoF Mobile Fronthaul With Statistical Data Compression and Multiband Modulation
 Abstract:As a counterpart of analog radio-over-fiber technology, digital radio-over-fiber (D-RoF) system, such as common public radio interface (CPRI), is a matured and robust solution to support RF signal delivery in traditional mobile fronthaul networks. In view of recent progresses in delta-sigma modulation, data compression, and advanced error correcting coding, the efficiency of D-RoF is significantly improved, which motivates researchers to re-evaluate the role of D-RoF in future mobile fronthaul networks to support 5G and beyond wireless communications. In this paper, we demonstrate two critical technologies to improve the transmission efficiency and flexibility of D-RoF systems. A fast-statistical-estimation based data compression algorithm is proposed to reduce the number of quantization digits in a D-RoF-based mobile fronthaul with low complexity and high quality. Combined with resampling and advanced modulation formats, data-transmission efficiency of a 25-Gbit/s D-RoF testbed is improved by around five times compared with uncompressed CPRI systems. On the other hand, we also experimentally demonstrate a point-to-multi-point (PTMP) D-RoF system with multiband modulation, which exhibits higher flexibility and better compatibility with multiple services and different radio-access technologies compared to existing schemes based on time interleaving. An experiment of 13.3-Gbit/s 4-band PTMP bidirectional D-RoF MFH is demonstrated. Combined with data compression, error free delivery of 6.4-Gbit/s 1024-QAM 5G-New-Radio-like signals is realized. Autors: Mu Xu;Feng Lu;Jing Wang;Lin Cheng;Daniel Guidotti;Gee-Kung Chang; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:17, pages: 3671 - 3679 Publisher: IEEE
» KiloHertz Bandwidth, Dual-Stage Haptic Device Lets You Touch Brownian Motion
 Abstract:This paper describes a haptic interface that has a uniform response over the entire human tactile frequency range. Structural mechanics makes it very difficult to implement articulated mechanical systems that can transmit high frequency signals. Here, we separated the frequency range into two frequency bands. The lower band is within the first structural mode of the corresponding haptic device while the higher one can be transmitted accurately by a fast actuator operating from conservation of momentum, that is, without reaction forces to the ground. To couple the two systems, we adopted a channel separation approach akin to that employed in the design of acoustic reproduction systems. The two channels are recombined at the tip of the device to give a uniform frequency response from DC to one kHz. In terms of mechanical design, the high-frequency transducer was embedded inside the tip of the main stage so that during operation, the human operator has only to interact with a single finger interface. In order to exemplify the type of application that would benefit from this kind of interface, we applied it to the haptic exploration with microscopic scales objects which are known to behave with very fast dynamics. The novel haptic interface was bilaterally coupled with a micromanipulation platform to demonstrate its capabilities. Operators could feel interaction forces arising from contact as well as those resulting from Brownian motion and could manoeuvre a micro bead in the absence of vision. Autors: Tianming Lu;Cécile Pacoret;David Hériban;Abdenbi Mohand-Ousaid;Stéphane Régnier;Vincent Hayward; Appeared in: IEEE Transactions on Haptics Publication date: Sep 2017, volume: 10, issue:3, pages: 382 - 390 Publisher: IEEE
» Kinesthetic Feedback During 2DOF Wrist Movements via a Novel MR-Compatible Robot
 Abstract:We demonstrate the interaction control capabilities of the MR-SoftWrist, a novel MR-compatible robot capable of applying accurate kinesthetic feedback to wrist pointing movements executed during fMRI. The MR-SoftWrist, based on a novel design that combines parallel piezoelectric actuation with compliant force feedback, is capable of delivering 1.5 N of torque to the wrist of an interacting subject about the flexion/extension and radial/ulnar deviation axes. The robot workspace, defined by admissible wrist rotation angles, fully includes a circle with a 20 deg radius. Via dynamic characterization, we demonstrate capability for transparent operation with low (10% of maximum torque output) backdrivability torques at nominal speeds. Moreover, we demonstrate a 5.5 Hz stiffness control bandwidth for a 14 dB range of virtual stiffness values, corresponding to 25%–125% of the device’s physical reflected stiffness in the nominal configuration. We finally validate the possibility of operation during fMRI via a case study involving one healthy subject. Our validation experiment demonstrates the capability of the device to apply kinesthetic feedback to elicit distinguishable kinetic and neural responses without significant degradation of image quality or task-induced head movements. With this study, we demonstrate the feasibility of MR-compatible devices like the MR-SoftWrist to be used in support of motor control experiments investigating wrist pointing under robot-applied force fields. Such future studies may elucidate fundamental neural mechanisms enabling robot-assisted motor skill learning, which is crucial for robot-aided neurorehabilitation. Autors: Andrew Erwin;Marcia K. O’Malley;David Ress;Fabrizio Sergi; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1489 - 1499 Publisher: IEEE
» L-Band Microwave Emission of Soil Freeze–Thaw Process in the Third Pole Environment
 Abstract:Soil freeze–thaw transition monitoring is essential for quantifying climate change and hydrologic dynamics over cold regions, for instance, the Third Pole. We investigate the L-band (1.4 GHz) microwave emission characteristics of soil freeze–thaw cycle via analysis of tower-based brightness temperature () measurements in combination with simulations performed by a model of soil microwave emission considering vertical variations of permittivity and temperature. Vegetation effects are modeled using Tor Vergata discrete emission model. The ELBARA-III radiometer is installed in a seasonally frozen Tibetan grassland site to measure diurnal cycles of L-band every 30 min, and supporting micrometeorological as well as volumetric soil moisture () and temperature profile measurements are also conducted. Soil freezing/thawing phases are clearly distinguished by using measurements at two polarizations, and further analyses show that: 1) the four-phase dielectric mixing model is appropriate for estimating permittivity of frozen soil; 2) the soil effective temperature is well comparable with the temperature at 25 cm depth when soil liquid water is freezing, while it is closer to the one measured at 5 cm when soil ice is thawing; and 3) the impact on caused by diurnal changes of ground permittivity is dominating the impact of changing ground temperature. Moreover, the simulations performed with the integrated Tor Vergata emission model an- Noah land surface model indicate that the signatures of diurnal soil freeze–thaw cycle is more sensitive to the liquid water content of the soil surface layer than the in situ measurements taken at 5 cm depth. Autors: Donghai Zheng;Xin Wang;Rogier van der Velde;Yijian Zeng;Jun Wen;Zuoliang Wang;Mike Schwank;Paolo Ferrazzoli;Zhongbo Su; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 5324 - 5338 Publisher: IEEE
» Laboratory Education of Modern Power Systems Using PHIL Simulation
 Abstract:Power hardware-in-the-loop (PHIL) simulation allows the connection of a physical power component (e.g., photovoltaic inverter) to a real-time simulated network. In this paper, PHIL simulation is used for laboratory education in a systematic way for the first time. Four important topics for the understanding of power system operation are selected and laboratory exercises are designed, respectively. The topics focus on the effects of increased integration of distributed generation (DG), namely, power sharing between synchronous generators and DG, voltage control with on load tap changer and DG, short circuits with inverter-based DG, and microgrid operation. The exercises start from the operation of the traditional power system and gradually incorporate DG-related topics that show both benefits and challenges. A hands-on approach is supported by the appropriate lab configuration consisting of two independent PHIL setups. The assessment of the laboratory exercises by the students is clearly positive underlining the value of PHIL simulation for power system education. Autors: Panos C. Kotsampopoulos;Vasilis A. Kleftakis;Nikos D. Hatziargyriou; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3992 - 4001 Publisher: IEEE
» Lane Determination With GPS Precise Point Positioning
 Abstract:Modern intelligent transport solutions can achieve an improvement of traffic flow on motorways. With lane-specific measurements and lane-specific control, more measures are possible. Single frequency precise point positioning (PPP) is a newly developed and affordable technique to achieve an improved position accuracy compared with global positioning system (GPS) standalone positioning. GPS-PPP allows for sub-meter accurate positioning, in real time, of vehicles on a motorway. This paper tests this technique in real life; moreover, it presents a methodology to map the lanes on a motorway using data collected by this technique. The methodology exploits the high accuracy and the fact that the most driving is within a lane. In a field test, a GPS-PPP equipped vehicle drives a specific motorway stretch 100 times, for which the GPS-PPP trajectory data are collected. Using these data, the positions and the widths of different lanes are successfully estimated. Comparison with the ground truth shows a dm accuracy. With the parametrized lanes, vehicles can be tracked down to a lane with the GPS-PPP device. Autors: Victor L. Knoop;Peter F. de Bakker;Christian C. J. M. Tiberius;Bart van Arem; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Sep 2017, volume: 18, issue:9, pages: 2503 - 2513 Publisher: IEEE
» Large Multi-Machine Power System Simulations Using Multi-Stage Adomian Decomposition
 Abstract:Multi-stage Adomian decomposition method (MADM) is a proven semi-analytical approximation solution technique for ordinary differential equations (ODEs), which provides a rapidly convergent series by integrating over multiple time intervals. Applicability of MADM for large nonlinear differential algebraic systems (DAEs) is established for the first time in this paper using the partitioned solution approach. Detailed models of power system components are approximated using MADM models. MADM applicability is verified on 7 widely used test systems ranging from 10 generators, 39 buses to 4092 generators, 13659 buses. Impact of the step size and the number of terms is investigated on the stability and accuracy of the method. An average speed up of 42% and 26% is observed in the solution time of ODEs alone using the MADM when compared to the midpoint-trapezoidal (TrapZ) method and the modified-Euler (ME) method, respectively. MADM accuracy is found to be similar to the ME and comparable to the TrapZ method. MADM stability properties are found to be better than the ME and weaker than the TrapZ method. An average speed up of 13% and 5.85% is observed in the overall solution time using MADM w.r.t. TrapZ and ME methods, respectively. Autors: Gurunath Gurrala;Disha Lagadamane Dinesha;Aleksandar Dimitrovski;Pannala Sreekanth;Srdjan Simunovic;Michael Starke; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3594 - 3606 Publisher: IEEE
» Large-Scale Location Prediction for Web Pages
 Abstract:Location information of Web pages plays an important role in location-sensitive tasks such as Web search ranking for location-sensitive queries. However, such information is usually ambiguous, incomplete, or even missing, which raises the problem of location prediction for Web pages. Meanwhile, Web pages are massive and often noisy, which pose challenges to the majority of existing algorithms for location prediction. In this paper, we propose a novel and scalable location prediction framework for Web pages based on the query-URL click graph. In particular, we introduce a concept of term location vectors to capture location distributions for all terms and develop an automatic approach to learn the importance of each term location vector for location prediction. Empirical results on a large URL set demonstrate that the proposed framework significantly improves the location prediction accuracy comparing with various representative baselines. We further provide a principled way to incorporate the proposed framework into the search ranking task and experimental results on a commercial search engine show that the proposed method remarkably boosts the ranking performance for location-sensitive queries. Autors: Yuening Hu;Changsung Kang;Jiliang Tang;Dawei Yin;Yi Chang; Appeared in: IEEE Transactions on Knowledge and Data Engineering Publication date: Sep 2017, volume: 29, issue:9, pages: 1902 - 1915 Publisher: IEEE
» Large-Scale Power System Robust Stability Analysis Based on Value Set Approach
 Abstract:This paper presents a method for robust stability analysis of large-scale power systems based on the value set approach. The order of the system is first reduced by the dimension reduction and modal truncation to capture the oscillation modes of interest. The characteristic polynomial is then obtained by the diagonal expansion, which allows the structure of coefficient functions to be exploited. The Mikhailov plot is generated with ease using the edge theorem and mapping theorem, and by inspection of the plot, the uncertainty's impact becomes transparent. The performance of the proposed method is tested on a 547-machine 8647-bus model of the actual North China system. The results of several case studies are reported, and related works are reviewed for comparison. Autors: Jinghao Zhou;Peng Shi;Deqiang Gan;Ying Xu;Huanhai Xin;Changming Jiang;Huan Xie;Tao Wu; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 4012 - 4023 Publisher: IEEE
» Large-Scale Tracking for Images With Few Textures
 Abstract:Image tracking provides crucial insight for the image motion, which generates essential information for incremental structure-from-motion reconstruction and camera pose estimation. Typical usages, such as 3D reconstruction and visual odometry, all rely on robust and accurate local feature tracking through consecutive images. Current algorithms realize feature tracking through matching features extracted from discriminant textures in the images, for which distinctive image content is required to obtain accurate feature matching. For images with few textures, usually, an insufficient number of features are extracted to perform reliable tracking in a series of sequential images. We propose a method that makes use of a limited number of discriminate features to explore other features without strong discriminant power. We develop a feature integrating surrounding salient points distribution knowledge, raw pixel value, and coordinate information to discover a significant amount of features in weakly textured areas in an image. We also incorporate epipolar geometry in the feature correspondence calculation by taking the distance from the matching candidate to its corresponding point's epipolar line into account. To reduce the number of unreliable features, we project the estimated 3D points back to the images. The reprojection error is standardized according to the 3D point's depth, which reduces the bias introduced by the object distance to the camera. We conduct experiments on a large dataset of Arctic sea ice images, mainly composed by planes of ices and sea water. The experimental results demonstrate that our method can perform fast and accurate tracking in weakly textured images. Autors: Guoyu Lu;Liqiang Nie;Scott Sorensen;Chandra Kambhamettu; Appeared in: IEEE Transactions on Multimedia Publication date: Sep 2017, volume: 19, issue:9, pages: 2117 - 2128 Publisher: IEEE
» Layer-Dependent Thermophotovoltaic Energy Conversion in 0.5-eV GaInAsSb Devices
 Abstract:By developing a compact dielectric model for GaInAsSb alloys, performance evaluation of 0.5-eV GaInAsSb diode has been systematically conducted by incorporating energy-dependent optical absorption and normal front-surface reflectivity. It is demonstrated here that, when comparing to that for zero surface reflection, incorporating front-surface reflection mainly results in 40% or so output power or efficiency degradation while shows little perturbation on the optimum device configuration and doping profiles, implying that some meaningful guidelines can still be acquired from device simulations without surface reflection. For the concerned alloy, we show that n+/p structure has a superior power conversion and beyond about cm doping density, the efficiency is insensitive to doping density in the light-doped layer. Autors: Xiao-Long Zhang;A-Bao Huang;Yu Wang;Yi-Yi Lou; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3706 - 3712 Publisher: IEEE
» Learn on Source, Refine on Target: A Model Transfer Learning Framework with Random Forests
 Abstract:We propose novel model transfer-learning methods that refine a decision forest model learned within a “source” domain using a training set sampled from a “target” domain, assumed to be a variation of the source. We present two random forest transfer algorithms. The first algorithm searches greedily for locally optimal modifications of each tree structure by trying to locally expand or reduce the tree around individual nodes. The second algorithm does not modify structure, but only the parameter (thresholds) associated with decision nodes. We also propose to combine both methods by considering an ensemble that contains the union of the two forests. The proposed methods exhibit impressive experimental results over a range of problems. Autors: Noam Segev;Maayan Harel;Shie Mannor;Koby Crammer;Ran El-Yaniv; Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence Publication date: Sep 2017, volume: 39, issue:9, pages: 1811 - 1824 Publisher: IEEE
» Learning Bregman Distance Functions for Structural Learning to Rank
 Abstract:We study content-based learning to rank from the perspective of learning distance functions. Standardly, the two key issues of learning to rank, feature mappings and score functions, are usually modeled separately, and the learning is usually restricted to modeling a linear distance function such as the Mahalanobis distance. However, the modeling of feature mappings and score functions are mutually interacted, and the patterns underlying the data are probably complicated and nonlinear. Thus, as a general nonlinear distance family, the Bregman distance is a suitable distance function for learning to rank, due to its strong generalization ability for distance functions, and its nonlinearity for exploring the general patterns of data distributions. In this paper, we study learning to rank as a structural learning problem, and devise a Bregman distance function to build the ranking model based on structural SVM. To improve the model robustness to outliers, we develop a robust structural learning framework for the ranking model. The proposed model Robust Structural Bregman distance functions Learning to Rank (RSBLR) is a general and unified framework for learning distance functions to rank. The experiments of data ranking on real-world datasets show the superiority of this method to the state-of-the-art literature, as well as its robustness to the noisily labeled outliers. Autors: Xi Li;Te Pi;Zhongfei Zhang;Xueyi Zhao;Meng Wang;Xuelong Li;Philip S. Yu; Appeared in: IEEE Transactions on Knowledge and Data Engineering Publication date: Sep 2017, volume: 29, issue:9, pages: 1916 - 1927 Publisher: IEEE
» Learning from Near Misses [Electrical Safety]
 Abstract:Examines ways engineers can learn from near-miss accidents. Some near-miss incidents are not reported, perhaps because the culture of the company doesn’t encourage a worker to report a near miss. If we really want to learn from these situations, we could publicize a general definition of a near miss that would include incidents where a worker could have been injured or killed if the work proceeded, and we could encourage prompt reporting so corrections can be made quickly before someone else is hurt or killed. Autors: Daniel Doan; Appeared in: IEEE Industry Applications Magazine Publication date: Sep 2017, volume: 23, issue:5, pages: 6 - 13 Publisher: IEEE
» Learning Transportation Modes From Smartphone Sensors Based on Deep Neural Network
 Abstract:In recent years, the importance of user information has increased rapidly for context-aware applications. This paper proposes a deep learning mechanism to identify the transportation modes of smartphone users. The proposed mechanism is evaluated on a database that contains more than 1000 h of accelerometer, magnetometer, and gyroscope measurements from five transportation modes, including still, walk, run, bike, and vehicle. Experimental results confirm the effectiveness of the proposed mechanism, which achieves approximately 95% classification accuracy and outperforms four well-known machine learning methods. Meanwhile, we investigated the model size and execution time of different algorithms to address practical issues. Autors: Shih-Hau Fang;Yu-Xaing Fei;Zhezhuang Xu;Yu Tsao; Appeared in: IEEE Sensors Journal Publication date: Sep 2017, volume: 17, issue:18, pages: 6111 - 6118 Publisher: IEEE
» Leveraging SDN and WebRTC for Rogue Access Point Security
 Abstract:Rogue access points (RAPs) are unauthorized devices connected to a network, providing unauthorized wireless access to one or more clients. Such devices pose significant risk to organizations, since they provide a convenient means for hackers and insiders to hide malicious or unsanctioned activities on industry, government, and campus networks. Yet, limitations inherent in traditional networks make detecting and removing such devices expensive, time consuming, and difficult to implement. For software-defined networks (SDNs), the risk of a network compromise due to RAPs is equally concerning, and methods for detecting RAPs within SDN architectures are needed. Hence, this paper leverages the capabilities of an SDN along with a trusted agent to detect and deny RAPs access to networks by using both generic and novel methods with minimal impact to performance. Three other contributions are included in this paper. They include: 1) utilizing an emerging Web architecture to detect hidden subnets; 2) developing the first, security-based, use case for Mininet-WiFi, a software-defined wireless network emulator; and 3) enhancing Ryuretic, a modular programming language for SDN application development. Autors: Jacob H. Cox;Russell Clark;Henry Owen; Appeared in: IEEE Transactions on Network and Service Management Publication date: Sep 2017, volume: 14, issue:3, pages: 756 - 770 Publisher: IEEE
» Leveraging Time Prediction and Error Compensation to Enhance the Scalability of Parallel Multi-Core Simulations
 Abstract:Due to synchronization overhead, it is challenging to apply the parallel simulation technique of multi-core processors at larger scales. Although the use of lax synchronization schemes could reduce overhead and balance the load between synchronous points, it introduces timing error and deteriorates simulation accuracy. Through observing the propagation paths of errors, we find that these paths always concentrate on some pivotal events. Based on the observation, we design a delay-calibration mechanism to alleviate errors. We decouple the timing and functional processes of the pivotal events, leveraging prediction technique of delays to connect two categories of the processes. Errors are traced throughout the timing processes of the pivotal events, and are deducted from the predicted delays before the delays are consumed by the functional processes. Therefore, through cleaning the errors at the successive pivot events, the mechanism decreases the simulated time deviations efficiently. Since the prediction and error deduction processes do not have any constraint on synchronizations, our approach largely maintains the scalability of lax synchronization schemes. Furthermore, our proposal is orthogonal to other parallel simulation techniques and can be used in conjunction with them. Experimental results show that error compensation improves the accuracy of lax synchronized simulations by 68 percent and achieves 97.8 percent accuracy when combined with an enhanced lax synchronization. Autors: Xiaodong Zhu;Junmin Wu;Tao Li; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Sep 2017, volume: 28, issue:9, pages: 2553 - 2566 Publisher: IEEE
» Licensing Engineering Professionals [Letter]
 Abstract: Autors: Gerald Aksherian; Appeared in: IEEE Technology and Society Magazine Publication date: Sep 2017, volume: 36, issue:3, pages: 10 - 10 Publisher: IEEE
» Light Extraction Enhancement of GaN-Based Light-Emitting Diodes With Textured Sidewalls and ICP-Transferred Nanohemispherical Backside Reflector
 Abstract:Textured-sidewall GaN-based light-emitting diodes (LEDs) with convex and 45° patterns and an inductively coupled plasma (ICP)-transferred nanohemispherical backside reflector, formed using an ICP etching process, are fabricated and studied. For devices with textured sidewalls, the scattering probability of photons at the GaN/air interface is increased and the light extraction efficiency is enhanced since photons are allowed to find escape cones in the horizontal direction. With the ICP-transferred nanohemispherical backside reflector, reflected photons can be easily scattered and redirected in arbitrary directions for light extraction and thus have more opportunities to escape the devices. The LED with 45° sidewalls and a backside reflector exhibited the significant improvements of 55.8%, 49.3%, 47.2%, and 55.4% in light output power, luminous flux, external quantum efficiency, and wall-plug efficiency, respectively, compared to those of a conventional LED without these specific designs (Device A). In addition, the higher intensities in a light emission mapping image and improved far-field patterns are obtained for the studied device. The enhanced optical performance is mainly attributed to the increased light extraction in all directions due to a significant reduction in the total internal reflection by the textured sidewalls and a backside reflector. Therefore, textured-sidewall structures and an ICP-transferred nanohemispherical backside reflector are promising for high-power GaN-based LED applications. Autors: Chun-Yen Chen;Wen-Chau Liu; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3672 - 3677 Publisher: IEEE
» Lightweight Hardware Architectures for the Present Cipher in FPGA
 Abstract:In recent years, the study of lightweight symmetric ciphers has gained interest due to the increasing demand for security services in constrained computing environments, such as in the Internet of Things. However, when there are several algorithms to choose from and different implementation criteria and conditions, it becomes hard to select the most adequate security primitive for a specific application. This paper discusses the hardware implementations of Present, a standardized lightweight cipher called to overcome part of the security issues in extremely constrained environments. The most representative realizations of this cipher are reviewed and two novel designs are presented. Using the same implementation conditions, the two new proposals and three state-of-the-art designs are evaluated and compared, using area, performance, energy, and efficiency as metrics. From this wide experimental evaluation, to the best of our knowledge, new records are obtained in terms of implementation size and energy consumption. In particular, our designs result to be adequate in regards to energy-per-bit and throughput-per-slice. Autors: Carlos Andres Lara-Nino;Arturo Diaz-Perez;Miguel Morales-Sandoval; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Sep 2017, volume: 64, issue:9, pages: 2544 - 2555 Publisher: IEEE
» Likelihood Analysis of Power Spectra and Generalized Moment Problems
 Abstract:We develop an approach to the spectral estimation that has been advocated by [A. Ferrante et al., “Time and spectral domain relative entropy: A new approach to multivariate spectral estimation,” IEEE Trans. Autom. Control, vol. 57, no. 10, pp. 2561–2575, Oct. 2012.] and, in the context of the scalar-valued covariance extension problem, by [P. Enqvist and J. Karlsson, “Minimal itakura-saito distance and covariance interpolation,” in Proc. 47th IEEE Conf. Decision Control, 2008, pp. 137–142]. The aim is to determine the power spectrum that is consistent with given moments and minimizes the relative entropy between the probability law of the underlying Gaussian stochastic process to that of a prior. The approach is analogous to the framework of earlier work by Byrnes, Georgiou, and Lindquist and can also be viewed as a generalization of the classical work by Burg and Jaynes on the maximum entropy method. In this paper, we present a new fast algorithm in the general case (i.e., for general Gaussian priors) and show that for priors with a specific structure the solution can be given in closed form. Autors: Tryphon T. Georgiou;Anders Lindquist; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4580 - 4592 Publisher: IEEE
» Limited-Magnitude Error-Correcting Gray Codes for Rank Modulation
 Abstract:We construct error-correcting codes over permutations under the infinity-metric, which are also Gray codes in the context of rank modulation, i.e., are generated as simple circuits in the rotator graph. These errors model limited-magnitude or spike errors, for which only single-error-detecting Gray codes are currently known. Surprisingly, the error-correcting codes we construct achieve a better asymptotic rate than that of presently known constructions not having the Gray property, and exceed the Gilbert-Varshamov bound. Additionally, we present efficient ranking and unranking procedures, as well as a decoding procedure that runs in linear time. Finally, we also apply our methods to solve an outstanding issue with error-detecting rank-modulation Gray codes (also known in this context as snake-in-the-box codes) under a different metric, the Kendall -metric, in the group of permutations over an even number of elements , where we provide asymptotically optimal codes. Autors: Yonatan Yehezkeally;Moshe Schwartz; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 5774 - 5792 Publisher: IEEE
» Line: Evaluating Software Applications in Unreliable Environments
 Abstract:Cloud computing has paved the way to the flexible deployment of software applications. This flexibility offers service providers a number of options to tailor their deployments to the observed and foreseen customer workloads, without incurring in large capital costs. However, cloud deployments pose novel challenges regarding application reliability and performance. Examples include managing the reliability of deployments that make use of spot instances, or coping with the performance variability caused by multiple tenants in a virtualized environment. In this paper, we introduce Line, a tool for performance and reliability analysis of software applications. Line solves layered queueing network (LQN) models, a popular class of stochastic models in software performance engineering, by setting up and solving an associated system of ordinary differential equations. A key differentiator of Line compared to existing solvers for LQNs is that Line incorporates a model of the environment the application operates in. This enables the modeling of reliability and performance issues such as resource failures, server breakdowns and repairs, slow start-up times, resource interference due to multitenancy, among others. This paper describes the Line tool, its support for performance and reliability modeling, and illustrates its potential by comparing Line predictions against data obtained from a cloud deployment. We also illustrate the applicability of Line with a case study on reliability-aware resource provisioning. Autors: Juan F. Pérez;Giuliano Casale; Appeared in: IEEE Transactions on Reliability Publication date: Sep 2017, volume: 66, issue:3, pages: 837 - 853 Publisher: IEEE
» Linear Subspace Ranking Hashing for Cross-Modal Retrieval
 Abstract:Hashing has attracted a great deal of research in recent years due to its effectiveness for the retrieval and indexing of large-scale high-dimensional multimedia data. In this paper, we propose a novel ranking-based hashing framework that maps data from different modalities into a common Hamming space where the cross-modal similarity can be measured using Hamming distance. Unlike existing cross-modal hashing algorithms where the learned hash functions are binary space partitioning functions, such as the sign and threshold function, the proposed hashing scheme takes advantage of a new class of hash functions closely related to rank correlation measures which are known to be scale-invariant, numerically stable, and highly nonlinear. Specifically, we jointly learn two groups of linear subspaces, one for each modality, so that features’ ranking orders in different linear subspaces maximally preserve the cross-modal similarities. We show that the ranking-based hash function has a natural probabilistic approximation which transforms the original highly discontinuous optimization problem into one that can be efficiently solved using simple gradient descent algorithms. The proposed hashing framework is also flexible in the sense that the optimization procedures are not tied up to any specific form of loss function, which is typical for existing cross-modal hashing methods, but rather we can flexibly accommodate different loss functions with minimal changes to the learning steps. We demonstrate through extensive experiments on four widely-used real-world multimodal datasets that the proposed cross-modal hashing method can achieve competitive performance against several state-of-the-arts with only moderate training and testing time. Autors: Kai Li;Guo-Jun Qi;Jun Ye;Kien A. Hua; Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence Publication date: Sep 2017, volume: 39, issue:9, pages: 1825 - 1838 Publisher: IEEE
» Linking Conductive Filament Properties and Evolution to Synaptic Behavior of RRAM Devices for Neuromorphic Applications
 Abstract:We perform a comparative study of HfO2 and Ta2O5 resistive switching memory (RRAM) devices for their possible application as electronic synapses. By means of electrical characterization and simulations, we link their electrical behavior (digital or analog switching) to the properties and evolution of the conductive filament (CF). More specifically, we identify that bias-polarity-dependent digital switching in HfO2 RRAM is primarily related to the creation and rupture of an oxide barrier. Conversely, the modulation of the CF size in Ta2O5 RRAM allows bias-polarity-independent analog switching with multiple states. Therefore, when the Ta2O5 RRAM is used to implement a synapse in multilayer perceptron neural networks operated by back-propagation algorithms, patterns in handwritten digits can be recognized with high accuracy. Autors: Jiyong Woo;Andrea Padovani;Kibong Moon;Myounghun Kwak;Luca Larcher;Hyunsang Hwang; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1220 - 1223 Publisher: IEEE
» Liver Segmentation on CT and MR Using Laplacian Mesh Optimization
 Abstract:Objective: The purpose of this paper is to describe a semiautomated segmentation method for the liver and evaluate its performance on CT-scan and MR images. Methods: First, an approximate 3-D model of the liver is initialized from a few user-generated contours to globally outline the liver shape. The model is then automatically deformed by a Laplacian mesh optimization scheme until it precisely delineates the patient's liver. A correction tool was implemented to allow the user to improve the segmentation until satisfaction. Results: The proposed method was tested against 30 CT-scans from the SLIVER07 challenge repository and 20 MR studies from the Montreal University Hospital Center, covering a wide spectrum of liver morphologies and pathologies. The average volumetric overlap error was 5.1% for CT and 7.6% for MRI and the average segmentation time was 6 min. Conclusion: The obtained results show that the proposed method is efficient, reliable, and could effectively be used routinely in the clinical setting. Significance: The proposed approach can alleviate the cumbersome and tedious process of slice-wise segmentation required for precise hepatic volumetry, virtual surgery, and treatment planning. Autors: Gabriel Chartrand;Thierry Cresson;Ramnada Chav;Akshat Gotra;An Tang;Jacques A. De Guise; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Sep 2017, volume: 64, issue:9, pages: 2110 - 2121 Publisher: IEEE
» Liver Venous Tree Separation via Twin-Line RANSAC and Murray’s Law
 Abstract:It is essential for physicians to obtain the accurate venous tree from abdominal CT angiography (CTA) series in order to carry out the preoperative planning and intraoperative navigation for hepatic surgery. In this process, one of the important tasks is to separate the given liver venous mask into its hepatic and portal parts. In this paper, we present a novel method for liver venous tree separation. The proposed method first concentrates on extracting potential vessel intersection points between hepatic and portal venous systems. Then, the proposed method focuses on modeling the vessel intersection neigh-borhoods with a robust twin-line random sample consensus (RANSAC) shape detector. Finally, the proposed method conducts the venous tree separation based on the results of the twin-line RANSAC as well as physical constraints posed by Murray’s Law. We test our method on 22 clinical CTA series and demonstrate its effectiveness. Autors: Zixu Yan;Feng Chen;Dexing Kong; Appeared in: IEEE Transactions on Medical Imaging Publication date: Sep 2017, volume: 36, issue:9, pages: 1887 - 1900 Publisher: IEEE
» LMI-Based Robust Predictive Load Frequency Control for Power Systems With Communication Delays
 Abstract:This paper presents a robust predictive load frequency control for power systems with uncertain parameters and time delays in communication networks. The goal of the proposed approach is to achieve good performance for the closed-loop system under practical problems of the network including uncertainties in the dynamic model, time delays in the system, and time-varying model. To this end, a decentralized state-feedback control law is obtained by solving an linear matrix inequality based optimization. The aim of the optimization problem is to regularize the frequency deviation with the minimum control effort. It is shown that the stability of the system is guaranteed with respect to the Lyapunov stability theorem. Moreover, the problem is reformulated as a centralized load frequency control (LFC) approach for single-area power systems, and also as a non-predictive LFC method with lower computational complexity. The performance and robustness of the proposed strategy are studied through simulation results in different cases of uncertain and time-varying single-area and multi-area power systems with time delays. Autors: Pegah Ojaghi;Mehdi Rahmani; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 4091 - 4100 Publisher: IEEE
» LMP Revisited: A Linear Model for the Loss-Embedded LMP
 Abstract:In this paper, the concept of locational marginal price (LMP) is revisited by analyzing the Karush–Kuhn–Tucker (KKT) condition of a general optimal power flow (OPF) problem. The impact of losses on LMP is investigated. Several well-known properties and formulations of the LMP are illustrated from a novel perspective. In particular, the special case of the lossless DC OPF model is discussed. Based on this theoretical analysis, a linear model for the loss-embedded LMP is proposed. The influence of losses on the LMP is recovered by solving a system of linear equations. The proposed method does not rely on strong subjective assumptions, such as the selection of reference buses or the determination of the “loss factor.” Case studies show that the proposed method has distinct advantages compared with the method currently practiced in major electricity markets. Autors: Zhifang Yang;Anjan Bose;Haiwang Zhong;Ning Zhang;Jeremy Lin;Qing Xia;Chongqing Kang; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 4080 - 4090 Publisher: IEEE
» Local and Remote Cooperation With Virtual and Robotic Agents: A P300 BCI Study in Healthy and People Living With Spinal Cord Injury
 Abstract:The development of technological applications that allow people to control and embody external devices within social interaction settings represents a major goal for current and future brain–computer interface (BCI) systems. Prior research has suggested that embodied systems may ameliorate BCI end-user’s experience and accuracy in controlling external devices. Along these lines, we developed an immersive P300-based BCI application with a head-mounted display for virtual-local and robotic-remote social interactions and explored in a group of healthy participants the role of proprioceptive feedback in the control of a virtual surrogate (Study 1). Moreover, we compared the performance of a small group of people with spinal cord injury (SCI) to a control group of healthy subjects during virtual and robotic social interactions (Study 2), where both groups received a proprioceptive stimulation. Our attempt to combine immersive environments, BCI technologies and neuroscience of body ownership suggests that providing realistic multisensory feedback still represents a challenge. Results have shown that healthy and people living with SCI used the BCI within the immersive scenarios with good levels of performance (as indexed by task accuracy, optimizations calls and Information Transfer Rate) and perceived control of the surrogates. Proprioceptive feedback did not contribute to alter performance measures and body ownership sensations. Further studies are necessary to test whether sensorimotor experience represents an opportunity to improve the use of future embodied BCI applications. Autors: Emmanuele Tidoni;Mohammad Abu-Alqumsan;Daniele Leonardis;Christoph Kapeller;Gabriele Fusco;Cristoph Guger;Cristoph Hintermüller;Angelika Peer;Antonio Frisoli;Franco Tecchia;Massimo Bergamasco;Salvatore Maria Aglioti; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1622 - 1632 Publisher: IEEE
» Local Condition Based Consensus Filtering With Stochastic Nonlinearities and Multiple Missing Measurements
 Abstract:This paper is concerned with the distributed -consensus filtering problem for a class of discrete time-varying systems with stochastic nonlinearities and multiple missing measurements. The stochastic nonlinearities are formulated by statistical means and the missing measurements are characterized by a set of random variables obeying Bernoulli distribution. A novel -consensus performance index is proposed to measure both the filtering accuracy of every node and the consensus among neighbor nodes. Then, a new concept called stochastic vector dissipativity is proposed wherein the dissipation matrix is formulated by a nonsingular substochastic matrix, which is skillfully constructed by a new defined interval function on the out-degree. A set of local sufficient conditions in terms of the recursive linear matrix inequalities is presented for each node such that the proposed -consensus performance can be guaranteed for the local augmented dynamics over the finite horizon. Furthermore, a novel algorithm proposed here can be implemented on each node. Finally, an illustrative simulation is presented to demonstrate the effectiveness and applicability of the proposed algorithm. Autors: Fei Han;Guoliang Wei;Derui Ding;Yan Song; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4784 - 4790 Publisher: IEEE
» Local Fringe Frequency Estimation Based on Multifrequency InSAR for Phase-Noise Reduction in Highly Sloped Terrain
 Abstract:The interferometric phases in highly sloped terrain have the characteristics of large fringe density, narrow width, low correlation, and under-sampling. The local fringe frequ- ency (LFF) is a criterion to evaluate the trend and magnitude of the local terrain gradient and can be employed to improve the quality of interferograms. The results of the traditional LFF estimation method can be affected by phase noise, and sometimes the phase unwrapping (PU) operation is also required for some local regions. When it comes to highly sloped terrain, the phenomenon of phase under-sampling may cause incorrectness in the absolute interferometric phase during the operation of PU and may then influence the accuracy of the whole estimation. In order to solve this problem, this letter proposes an extended maximum-likelihood method for LFF estimation based on the multifrequency interferometric synthetic aperture radar (InSAR) data. Through the differences in the LFF between the different frequency InSAR data, the estimation quality map is introduced to modify the large error in certain regions by local 2-D fitting and thus achieves a accurate estimation of LFF in highly sloped terrain. Finally, the estimated results of LFF are used to guide the process of phase filtering. Simulated data and real airborne dual-frequency InSAR data are both employed to validate this proposed method. Autors: Zegang Ding;Zhen Wang;Sheng Lin;Tiandong Liu;Qi Zhang;Teng Long; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1527 - 1531 Publisher: IEEE
» Log-Normal Statistics in Filamentary RRAM Devices and Related Systems
 Abstract:We present a phenomenological theory of the log-normal statistics commonly observed in filamentary resistive memory and related devices. Based on the central limit theorem that statistics are shown to emerge regardless of the underlying material properties when the processes are dominated by thermal activation or tunneling. That takes place in particular for the read-out resistances in the high-resistive (OFF) state, and the random telegraph noise amplitudes, but can be observed in the low-resistive (ON) state as well. We show that the statistics of switching times becomes log-normal when the switching is due to the field induced nucleation. Autors: V. G. Karpov;D. Niraula; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1240 - 1243 Publisher: IEEE
» Lookup: Robust and Accurate Indoor Localization Using Visible Light Communication
 Abstract:A novel indoor localization system is presented, where LED beacons are utilized to determine the position of the target sensor, including a camera, an inclinometer, and a magnetometer. The beacons, which can be a part of the existing lighting infrastructure, transmit their identifiers for long distances using visible light communication techniques. The sensor is able to sense and detect the high-frequency (flicker free) code by properly undersampling the transmitted signal. The localization is performed using novel geometric and consensus-based techniques, which tolerate well measurement inaccuracies and sporadic outliers. The performance of the system is analyzed using simulations and real measurements. According to large-scale tests in realistic environments, the accuracy of the proposed system is in the low decimeter range. Autors: Gyula Simon;Gergely Zachár;Gergely Vakulya; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Sep 2017, volume: 66, issue:9, pages: 2337 - 2348 Publisher: IEEE
» Loss and Noise Analysis of Transformer ComprisingGrooved Grain-Oriented Silicon Steel
 Abstract:For the reduction of transformer noise and efficient use of energy, we developed a domain-refined highly grain-oriented silicon steel with a linearly grooved surface by an electrolytic etching method. The steel showed very low iron loss even after a high-temperature annealing process, such as stress relief annealing, while magnetic flux density at 800 A/m, which is one of the very fundamental evaluation criteria for grain-oriented silicon steel, was lower than that without grooves. In light of our previous study, steels with a low flux density are disadvantageous for lowering transformer noise, but there have been no reports on the detailed noise property of this grooved grain-oriented silicon steel. In this paper, we investigated transformer noise as well as the transformer loss for the first time by fabricating three model transformers, each of which comprised one of the following grain-oriented electrical steels: grooved grain-oriented silicon steel having flux density of 1.90 T at 800 A/m, non-grooved grain-oriented silicon steel having flux density of 1.93 T at 800 A/m, and non-grooved grain-oriented silicon steel having flux density of 1.90 T at 800 A/m. As a result, transformer loss exhibited a tendency similar to the loss of a single sheet, and the grooved grain-oriented silicon steel showed the lowest loss. As for noise, even with the lower flux density, the grooved grain-oriented silicon steel showed a very low noise level equivalent to that of the non-grooved grain-oriented silicon steel with the high flux density, while the non-grooved grain-oriented silicon steel with the low flux density showed the largest noise level. From the results of magnetostriction measurements and dynamic domain observation by a newly developed method, it was found that the grooves had little influence on the generation of magnetic domains, which increased magnetostriction and transformer noise. Thus, we confirmed that low noise and low loss properties of the transformer were - oth realized by the application of the grooved silicon steel. Autors: S. Takajo;T. Ito;T. Omura;S. Okabe; Appeared in: IEEE Transactions on Magnetics Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 6 Publisher: IEEE

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