#### Electrical and Electronics Engineering publications abstract of: 09-2017 sorted by title, page: 7

» Enhancement-Mode AlGaN/GaN Fin-MOSHEMTs on Si Substrate With Atomic Layer Epitaxy MgCaO
 Abstract:We have demonstrated high-performance enhancement-mode or normally-off AlGaN/GaN fin-MOSHEMTs on a Si substrate with various fin width of 100–210 nm using atomic layer epitaxy (ALE) MgCaO as the gate dielectric. Through the fixed negative charges in MgCaO depleting the channel at the fin sidewalls, in contrast to the usual positive charges in atomic layer deposited amorphous Al2O3, the threshold voltage () is positively shifted and normally-off device is realized. A high maximum drain current () of 670 mA/mm, high on/off ratio of 1010 ~ 1012, and of 1 V have been achieved on the device. Combining with negligible – hysteresis of 30 mV and current collapse, the ALE MgCaO fin-MOSHEMT turns out to be a promising candidate for the future GaN power device applications. Autors: Hong Zhou;Xiabing Lou;Sang Bok Kim;Kelson D. Chabak;Roy G. Gordon;Peide D. Ye; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1294 - 1297 Publisher: IEEE
» Enhancing Multiuser MIMO Through Opportunistic D2D Cooperation
 Abstract:We propose a cellular architecture that combines multiuser MIMO downlink with opportunistic use of unlicensed Industrial, Scientific, and Medical Radio (ISM) bands to establish device-to-device (D2D) cooperation. The architecture consists of a physical-layer cooperation scheme based on forming downlink virtual MIMO channels through D2D relaying, and a novel resource allocation strategy for such D2D-enabled networks. We prove the approximate optimality of the physical-layer scheme, and demonstrate that such cooperation boosts the effective of the weakest user in the system, especially in the many-user regime, due to multiuser diversity. To harness this physical-layer scheme, we formulate the cooperative user scheduling and the relay selection problem using the network utility maximization framework. For such a cooperative network, we propose a novel utility metric that jointly captures fairness in throughput and the cost of relaying in the system. We propose a joint user scheduling and relay selection algorithm, which we prove to be asymptotically optimal. We study the architecture through system-level simulations over a wide range of scenarios. The highlight of these simulations is an approximately improvement in data rate for cell-edge (bottom fifth-percentile) users (over the state-of-the-art) while still improving the overall throughput, and considering various system constraints. Autors: Can Karakus;Suhas Diggavi; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 5616 - 5629 Publisher: IEEE
» Enhancing Test Compression With Dependency Analysis for Multiple Expansion Ratios
 Abstract:Scan test data compression is widely used in industry to reduce test data volume (TDV) and test application time (TAT). This paper shows how multiple scan chain expansion ratios can help to obtain high test data compression in system-on-chips. Scan chains are partitioned with a higher expansion ratio than normal in scan compression mode and then are gradually concatenated based on a cost function to detect any faults that could not be detected at the higher expansion ratios. It improves the overall test compression ratio since it potentially allows faults to be detected at the highest expansion ratio. This paper introduces a new cost function to choose scan chain concatenation candidates for concatenation for multiple expansion ratios. To avoid TDV and TAT increase by scan concatenation, the proposed method takes a logic structure and scan chain length into consideration. Experiment results show the proposed method reduces TAT and TDV by 53%–64% compared with a traditional scan compression method. Autors: Taehee Lee;Nur A. Touba;Joon-Sung Yang; Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Publication date: Sep 2017, volume: 36, issue:9, pages: 1571 - 1579 Publisher: IEEE
» Erratum to “A 200–1380 kHz Quadrifrequency Focused Ultrasound Transducer for Neurostimulation in Rodents and Primates: Transcranial In Vitro Calibration and Numerical Study of the Influence of Skull Cavity”
 Abstract:In the above paper [1], one maximum pressure listed in Table I, page 719, should be corrected. This error occurred when reporting the maximum pressure estimated in the rat brain at 1380 kHz (line 4, last column). The right value (7 MPa) does not change the discussion, and is in line with the 83% estimated pressure gain that was initially reported in rat brain (line 7, last column). Here we provide the correct table. Autors: Charlotte Constans;Thomas Deffieux;Pierre Pouget;Mickael Tanter;Jean-François Aubry; Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Publication date: Sep 2017, volume: 64, issue:9, pages: 1417 - 1417 Publisher: IEEE
» Error Characterization, Mitigation, and Recovery in Flash-Memory-Based Solid-State Drives
 Abstract:NAND flash memory is ubiquitous in everyday life today because its capacity has continuously increased and cost has continuously decreased over decades. This positive growth is a result of two key trends: 1) effective process technology scaling; and 2) multi-level (e.g., MLC, TLC) cell data coding. Unfortunately, the reliability of raw data stored in flash memory has also continued to become more difficult to ensure, because these two trends lead to 1) fewer electrons in the flash memory cell floating gate to represent the data; and 2) larger cell-to-cell interference and disturbance effects. Without mitigation, worsening reliability can reduce the lifetime of NAND flash memory. As a result, flash memory controllers in solid-state drives (SSDs) have become much more sophisticated: they incorporate many effective techniques to ensure the correct interpretation of noisy data stored in flash memory cells. In this article, we review recent advances in SSD error characterization, mitigation, and data recovery techniques for reliability and lifetime improvement. We provide rigorous experimental data from state-of-the-art MLC and TLC NAND flash devices on various types of flash memory errors, to motivate the need for such techniques. Based on the understanding developed by the experimental characterization, we describe several mitigation and recovery techniques, including 1) cell-to-cell interference mitigation; 2) optimal multi-level cell sensing; 3) error correction using state-of-the-art algorithms and methods; and 4) data recovery when error correction fails. We quantify the reliability improvement provided by each of these techniques. Looking forward, we briefly discuss how flash memory and these techniques could evolve into the future. Autors: Yu Cai;Saugata Ghose;Erich F. Haratsch;Yixin Luo;Onur Mutlu; Appeared in: Proceedings of the IEEE Publication date: Sep 2017, volume: 105, issue:9, pages: 1666 - 1704 Publisher: IEEE
» eShiver: Lateral Force Feedback on Fingertips through Oscillatory Motion of an Electroadhesive Surface
 Abstract:We describe a new haptic force feedback device capable of creating lateral shear force on a bare fingertip—the eShiver. The eShiver creates a net lateral force from in-plane oscillatory motion of a surface synchronized with a “friction switch” based on Johnsen-Rahbek electroadhesion. Using an artificial finger, a maximum net lateral force of 300 mN is achieved at 55 Hz lateral oscillation frequency, and net force is shown to be a function of velocity and applied voltage, as well as the phase between them. A second set of experiments is carried out on a human finger, and a lateral force of up to 450 mN is achieved at a lateral oscillation frequency of 1,000 Hz. This force is reached at a peak lateral surface velocity of 400 mm/s and a peak applied voltage of 400 V. We develop a simple lumped parameter model of the eShiver, and a time domain simulation of the artificial finger is shown to agree with the experimental results. Three distinct zones of operation are found, which predict the limitations of force generation and which may be used for optimization. The human finger is found to be similar to the artificial finger in its dependence on actuation parameters, suggesting that the same lumped parameter model may be applied, albeit with different parameters. Curiously, the friction force due to Johnsen-Rahbek electroadhesion is found to increase substantially over time as the finger remains in contact with the surface. Considerations for optimizing the performance of the eShiver are discussed. Autors: Joseph Mullenbach;Michael Peshkin;J. Edward Colgate; Appeared in: IEEE Transactions on Haptics Publication date: Sep 2017, volume: 10, issue:3, pages: 358 - 370 Publisher: IEEE
» ESO-Based Inertia Emulation and Rotor Speed Recovery Control for DFIGs
 Abstract:In recent years, with the ever increasing penetration of wind generation, great concerns have been raised since the constantly decline of system's inertia may considerably deteriorate the frequency stability of power system. In this regard, an inertial response control technique is proposed to enable wind generators to provide the power system with controlled inertia in need via releasing energy to or absorbing energy from the system. In this paper, an extended state observer (ESO)-based inertia emulation controller (InEC) is proposed for doubly-fed induction generators (DFIGs), which is shown to be robust to measurement noise and changing working conditions. In addition, to mitigate potential adverse impacts of rotor speed recovery control (RSRC) of DFIGs on system frequency, an ESO-based RSRC is derived, allowing a schedulable dynamic of speed recovery. Experiments carried out on a power hardware-in-loop testbed manifest that the proposed controllers outperform the traditional proportional–differential type InEC and proportional–integral type RSRC in performance and robustness. Autors: Feng Liu;Zhangwei Liu;Shengwei Mei;Wei Wei;Yaxin Yao; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 1209 - 1219 Publisher: IEEE
» Establishing Effective Global Virtual Student Teams
 Abstract:Research problem: In the educational arena, virtual teams made up of students who are located in more than one country are becoming increasingly commonplace. However, studies of the technological, social, and organizational factors that contribute to the success of these global virtual student teams (GVSTs) have yet to be systematically identified and discussed. In this paper, we seek to address this gap in our knowledge, drawing on several years of experience with GVSTs and addressing the following research question: How can university instructors establish effective GVST projects? Situating the case: The cases that we explore in this paper involve GVSTs with team members located variously in Hong Kong (all four cases), the USA (two cases), the UK (one case), and Singapore (one case). Students are a mix of undergraduate and graduate. How the case was studied: Our pedagogical purpose for running the GVST projects was to expose students to international communication and negotiation practices. The case designs involved situations where the student team members had to work collaboratively on a variety of tasks. We collected observational data and survey data, and required the team members to submit individual reflective reports about their learning experiences. About the case: We examine cultural differences among teams. We also note how issues of time and space vary across these teams, and consider how sufficient trust may be developed between team members to ensure productive work. Conclusion: From the four cases, we elicit 10 pertinent operational factors that should be of value to educators planning GVST projects. Autors: Robert M. Davison;Niki Panteli;Andrew M. Hardin;Mark A. Fuller; Appeared in: IEEE Transactions on Professional Communication Publication date: Sep 2017, volume: 60, issue:3, pages: 317 - 329 Publisher: IEEE
» Estimation of Finger Joint Angles Based on Electromechanical Sensing of Wrist Shape
 Abstract:An approach to finger motion capture that places fewer restrictions on the usage environment and actions of the user is an important research topic in biomechanics and human-computer interaction. We proposed a system that electrically detects finger motion from the associated deformation of the wrist and estimates the finger joint angles using multiple regression models. A wrist-mounted sensing device with 16 electrodes detects deformation of the wrist from changes in electrical contact resistance at the skin. In this study, we experimentally investigated the accuracy of finger joint angle estimation, the adequacy of two multiple regression models, and the resolution of the estimation of total finger joint angles. In experiments, both the finger joint angles and the system output voltage were recorded as subjects performed flexion/extension of the fingers. These data were used for calibration using the least-squares method. The system was found to be capable of estimating the total finger joint angle with a root-mean-square error of 29–34 degrees. A multiple regression model with a second-order polynomial basis function was shown to be suitable for the estimation of all total finger joint angles, but not those of the thumb. Autors: Junki Kawaguchi;Shunsuke Yoshimoto;Yoshihiro Kuroda;Osamu Oshiro; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1409 - 1418 Publisher: IEEE
» Estimation of Remaining Useful Lifetime of Piezoelectric Transducers Based on Self-Sensing
 Abstract:Piezoelectric transducers are used in a wide range of applications. Reliability of these transducers is an important aspect in their application. Prognostics, which involve continuous monitoring of the health of technical systems and using this information to estimate the current health state and consequently predict the remaining useful lifetime ( ), can be used to increase the reliability, safety, and availability of the transducers. This is achieved by utilizing the health state and predictions to adaptively control the usage of the components or to schedule appropriate maintenance without interrupting operation. In this work, a prognostic approach utilizing self-sensing, where electric signals of a piezoelectric transducer are used as the condition monitoring data, is proposed. The approach involves training machine learning algorithms to model the degradation of the transducers through a health index and the use of the learned model to estimate the health index of similar transducers. The current health index is then used to estimate of test components. The feasibility of the approach is demonstrated using piezoelectric bimorphs and the results show that the method is accurate in predicting the health index and . Autors: James Kuria Kimotho;Tobias Hemsel;Walter Sextro; Appeared in: IEEE Transactions on Reliability Publication date: Sep 2017, volume: 66, issue:3, pages: 914 - 923 Publisher: IEEE
» Estimation of Sampling Period for Stochastic Nonlinear Sampled-Data Systems With Emulated Controllers
 Abstract:This note focuses on determining the value of the maximum allowable sampling period (MASP) that guarantees the stability of stochastic nonlinear sampled-data systems with emulated controllers. Two methods are proposed to compute MASP, one based on sufficient Lyapunov-like conditions on stabilization of stochastic nonlinear systems in mean square and the other from applying Barbalat's Lemma. Comparison studies are made and illustrated for the two methods by a numerical example. Autors: Yong-Feng Gao;Xi-Ming Sun;Changyun Wen;Wei Wang; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4713 - 4718 Publisher: IEEE
» Ethics in Robotics Research: CERNA Mission and Context
 Abstract:This article summarizes the recommendations concerning robotics as issued by the Commission for the Ethics of Research in Information Sciences and Technologies (CERNA), the French advisory commission for the ethics of information and communication technology (ICT) research. Robotics has numerous applications in which its role can be overwhelming and may lead to unexpected consequences. In this rapidly evolving technological environment, CERNA does not set novel ethical standards but seeks to make ethical deliberation inseparable from scientific activity. Additionally, it provides tools and guidance for researchers and research institutions. Autors: Alexei Grinbaum;Raja Chatila;Laurence Devillers;Jean-Gabriel Ganascia;Catherine Tessier;Max Dauchet; Appeared in: IEEE Robotics & Automation Magazine Publication date: Sep 2017, volume: 24, issue:3, pages: 139 - 145 Publisher: IEEE
» Evaluation of a “Field Cage” for Electric Field Control in GaN-Based HEMTs That Extends the Scalability of Breakdown Into the kV Regime
 Abstract:A distributed impedance “field cage” structure is proposed and evaluated for electric field control in GaN-based, lateral high electron mobility transistors operating as kilovolt-range power devices. In this structure, a resistive voltage divider is used to control the electric field throughout the active region. The structure complements earlier proposals utilizing floating field plates that did not employ resistively connected elements. Transient results, not previously reported for field plate schemes using either floating or resistively connected field plates, are presented for ramps of V/ns. For both dc and transient results, the voltage between the gate and drain is laterally distributed, ensuring that the electric field profile between the gate and drain remains below the critical breakdown field as the source-to-drain voltage is increased. Our scheme indicates promise for achieving the breakdown voltage scalability to a few kilovolts. Autors: Brian D. Tierney;Sukwon Choi;Sandeepan DasGupta;Jeramy R. Dickerson;Shahed Reza;Robert J. Kaplar;Albert G. Baca;Matthew J. Marinella; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3740 - 3747 Publisher: IEEE
» Evaluation of Modal Power Distribution of Automotive Optical Gigabit Ethernet Connections
 Abstract:Automotive optical gigabit Ethernet is a technology that is expected to realize autonomous driving cars with notable benefits: electromagnetic interference free, lighter weight, and higher data communication. Plastic optical fibers have been used in automotive optical networks since 1998. To secure a higher data rate, two issues must be considered: the need for modal power distribution (MPD) control and the lack of link margin. Here, we performed a combined study of MPD and the frequency characteristics of a 15-m optical fiber cable with multiple connections. The results reveal that the links have transmission directivity and the number of connections influences the bandwidth with different MPDs, as shown in encircled angular flux (EAF) profiles. We also show that automotive optical connections typically contain an air gap that generates higher mode radiation. To minimize this radiation, we filled the gap with a cured gel. We found that the EAF profile shifts from 13.8° to 15.4° at 50% EAF with a 1.75-dB insertion loss improvement based on the shift at z/a = 3.1 (where z indicates the axial misalignment at the connection, and a is the core radius). The approach presented here is an effective solution for facilitating the rapid realization of automotive optical gigabit communication. Autors: Shigeru Kobayashi;Koji Horiguchi;Yasuhiro Hyakutake;Okihiro Sugihara; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:17, pages: 3664 - 3670 Publisher: IEEE
» Event-Triggered State Estimation With an Energy Harvesting Sensor
 Abstract:In this paper, a problem of event-triggered state estimation for a linear Gaussian system with an energy harvesting sensor is investigated. A stochastic energy-dependent event-triggering transmission protocol is proposed to balance the communication rate and estimation performance according to the sensor's battery energy. The joint conditional probability distribution of the state and sensor's energy level on the combined set-valued and point-valued event-triggered measurements available to the remote estimator is derived. Based on this distribution, the recursive minimum mean squared error estimates of the state and sensor energy level are obtained. Also, the relationship between the average communication rate and energy harvesting rate is discussed. Finally, a numerical example is provided to evaluate the effectiveness of the proposed results. Autors: Jiarao Huang;Dawei Shi;Tongwen Chen; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4768 - 4775 Publisher: IEEE
» Evidence of Hot-Electron Effects During Hard Switching of AlGaN/GaN HEMTs
 Abstract:This paper reports on the impact of soft- and hard-switching conditions on the dynamic ON-resistance of AlGaN/GaN high-electron mobility transistors. For this study, we used a special double pulse setup, which controls the overlapping of the drain and gate waveforms (thus inducing soft and hard switching), while measuring the corresponding impact on the ON-resistance, drain current, and electroluminescence (EL). The results demonstrate that the analyzed devices do not suffer from dynamic increase when they are submitted to soft switching up to V. On the contrary, hard-switching conditions lead to a measurable increase in the dynamic ON-resistance (dynamic-. The increase in dynamic induced by hard switching is ascribed to hot-electrons effects: during each switching event, the electrons in the channel are accelerated by the high electric field and subsequently trapped in the AlGaN/GaN heterostructure or at the surface. This hypothesis is supported by the following results: 1) the increase in is correlated with the EL signal measured under hard-switching conditions and 2) the impact of hard switching on dynamic becomes weaker at high-temperature levels, as the average energy of hot electrons decreases due to the increase scattering with the lattice. Autors: I. Rossetto;M. Meneghini;A. Tajalli;S. Dalcanale;C. De Santi;P. Moens;A. Banerjee;E. Zanoni;G. Meneghesso; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3734 - 3739 Publisher: IEEE
» Evidence of Time-Dependent Vertical Breakdown in GaN-on-Si HEMTs
 Abstract:This paper demonstrates and investigates the time-dependent vertical breakdown of GaN-on-Si power transistors. The study is based on electrical characterization, dc stress tests and electroluminescence measurements. We demonstrate the following original results: 1) when submitted to two-terminal (drain-to-substrate) stress, the AlGaN/GaN transistors show a time-dependent degradation process, which leads to the catastrophic failure of the devices; 2) time-to-failure follows a Weibull distribution and is exponentially dependent on stress voltage; 3) the degradation mechanism is strongly field dependent and weakly thermally activated, with an activation energy of 0.25 eV; and 4) emission microscopy suggests that vertical current flows under the whole drain area, possibly through extended defects. The catastrophic failure occurs at random positions under the drain contact. The time-dependent failure is ascribed to a percolation process activated by the high-electric field that leads to the generation of localized shunt paths between drain and substrate. Autors: Matteo Borga;Matteo Meneghini;Isabella Rossetto;Steve Stoffels;Niels Posthuma;Marleen Van Hove;Denis Marcon;Stefaan Decoutere;Gaudenzio Meneghesso;Enrico Zanoni; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3616 - 3621 Publisher: IEEE
» Evolutionary Behavior Tree Approaches for Navigating Platform Games
 Abstract:Computer games are highly dynamic environments, where players are faced with a multitude of potentially unseen scenarios. In this paper, AI controllers are applied to the Mario AI benchmark platform, by using the grammatical evolution system to evolve behavior tree structures. These controllers are either evolved to both deal with navigation and reactiveness to elements of the game or used in conjunction with a dynamic A* approach. The results obtained highlight the applicability of behavior trees as representations for evolutionary computation and their flexibility for incorporation of diverse algorithms to deal with specific aspects of bot control in game environments. Autors: Miguel Nicolau;Diego Perez-Liebana;Michael O’Neill;Anthony Brabazon; Appeared in: IEEE Transactions on Computational Intelligence and AI in Games Publication date: Sep 2017, volume: 9, issue:3, pages: 227 - 238 Publisher: IEEE
» Experimental and Simulation Study of Silicon Nanowire Transistors Using Heavily Doped Channels
 Abstract:The experimental results from 8 nm diameter silicon nanowire junctionless field-effect transistors with gate lengths of 150 nm are presented that demonstrate on-currents up to 1.15 mA/m for 1.0 V and 2.52 mA/m for 1.8 V gate overdrive with an off-current set at 100 nA/m. On- to off-current ratios above with a subthreshold slope of 66 mV/dec are demonstrated at 25 C. Simulations using drift-diffusion which include density-gradient quantum corrections provide excellent agreement with the experimental results. The simulations demonstrate that the present silicon-dioxide gate dielectric only allows the gate to be scaled to 25 nm length before short-channel effects significantly reduce the performance. If high-K dielectrics replace some parts of the silicon dioxide then the technology can be scaled to at least 10 nm gatelength. Autors: Vihar P. Georgiev;Muhammad M. Mirza;Alexandru-Iustin Dochioiu;Fikru Adamu-Lema;Salvatore M. Amoroso;Ewan Towie;Craig Riddet;Donald A. MacLaren;Asen Asenov;Douglas J. Paul; Appeared in: IEEE Transactions on Nanotechnology Publication date: Sep 2017, volume: 16, issue:5, pages: 727 - 735 Publisher: IEEE
» Experimental Demonstration of Efficient Spin–Orbit Torque Switching of an MTJ With Sub-100 ns Pulses
 Abstract:Efficient generation of spin currents from charge currents is of high importance for memory and logic applications of spintronics. In particular, generation of spin currents from charge currents in high spin–orbit coupling metals has the potential to provide a scalable solution for embedded memory. We demonstrate a net reduction in the critical charge current for spin torque-driven magnetization reversal via using spin–orbit mediated spin current generation. We scaled the dimensions of the spin–orbit electrode to 400 nm and the nanomagnet to 270 nm nm in a three-terminal spin–orbit torque, magnetic tunnel junction (SOT-MTJ) geometry. Our estimated effective spin Hall angle is 0.15–0.20 using the ratio of zero-temperature critical current from spin Hall switching and estimated spin current density for switching the magnet. We show bidirectional transient switching using spin–orbit generated spin torque at 100 ns switching pulses reliably followed by transient read operations. We finally compare the static and dynamic response of the SOT-MTJ with transient spin circuit modeling showing the performance of scaled SOT-MTJs to enable nanosecond class non-volatile MTJs. Autors: Tanay A. Gosavi;Sasikanth Manipatruni;Sriharsha V. Aradhya;Graham E. Rowlands;Dmitri Nikonov;Ian A. Young;Sunil A. Bhave; Appeared in: IEEE Transactions on Magnetics Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 7 Publisher: IEEE
» Experimental Observation of Negative Susceptance in HfO2-Based RRAM Devices
 Abstract:Negative susceptance is experimentally measured in the low resistance state of TiN/Ti/HfO2/W resistive RAM memories. A meminductive-like behavior appears along with the memristive effects. A detailed study of small-signal parameters measured at 0 V after applying positive and negative voltage pulses is presented. A simple model for the conductive filaments consisting in a resistance in series with an inductance is used. In the equivalent circuit, both elements are in parallel with the geometrical capacitance of the structure. Both resistance and inductance show two clearly differentiate states. Positive voltages switch the device to the ON state, in which the resistance value is low and the inductance value is high. By applying appropriate negative voltages, the device switches to the OFF state, in which resistance value is high and inductance becomes negligible. The negative susceptance could be related to lags between current and electric field due to transport mechanisms occurring in the ON state. Autors: S. Dueñas;H. Castán;H. García;Óscar G. Ossorio;Luis A. Domínguez;E. Miranda; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1216 - 1219 Publisher: IEEE
» Exploiting Unused Spare Columns and Replaced Columns to Enhance Memory ECC
 Abstract:Due to the emergence of extremely high density memory along with the growing number of embedded memories, memory yield is an important issue. Memory self-repair using redundancies to increase the yield of memories is widely used. Because high density memories are vulnerable to soft errors, memory error correction code (ECC) plays an important role in memory design. In this paper, methods to exploit spare columns including replaced defective columns are proposed to improve memory ECC. To utilize replaced defective columns, the defect information needs to be stored. Two approaches to store defect information are proposed—one is to use a spare column and the other is to use a content-addressable-memory. Experimental results show that the proposed method can significantly enhance the ECC performance. Autors: Hyunseung Han;Nur A. Touba;Joon-Sung Yang; Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Publication date: Sep 2017, volume: 36, issue:9, pages: 1580 - 1591 Publisher: IEEE
» Exploring Polymer Nanofiber Mechanics: A review of the methods for determining their properties.
 Abstract:Polymer nanofibers are increasingly being used in broad and diverse areas. In addition to the intrinsic chemical properties of the polymer, the physical and mechanical properties of the fiber are also important in determining its suitability for a given application. But measuring the mechanical properties and understanding their relationship to the structure and dimensions of the polymer nanofibers present some unique challenges. The atomic force microscope (AFM) has the force-sensing sensitivity and three-dimensional (3-D) spatial resolution necessary for this type of experiment. Several methods have been developed based on the AFM. The threepoint bending test approach is one of the most common, and several models have been developed for results interpretation. Autors: Ying Li;Wankei Wan; Appeared in: IEEE Nanotechnology Magazine Publication date: Sep 2017, volume: 11, issue:3, pages: 16 - 28 Publisher: IEEE
» Exploring RapidIO Technology Within a DAQ System Event Building Network
 Abstract:RapidIO (http://rapidio.org/) technology is a packet-switched high-performance fabric, which has been under active development since 1997. The technology is used in all 4G/LTE base stations worldwide. RapidIO is also used in embedded systems that require high reliability, low latency, and deterministic operations in a heterogeneous environment. RapidIO has several offloading features in hardware, therefore relieving the CPUs from time- and power-consuming work. Most importantly, it allows for remote direct memory access and thus zero-copy data transfer. In addition, it lends itself readily to integration with field-programmable gate arrays. In this paper, we investigate RapidIO as a technology for high-speed data acquisition (DAQ) networks, in particular the DAQ system of an LHC experiment. We present measurements using a generic multiprotocol event-building emulation tool that was developed for the LHCb experiment. Event building using a local area network, such as the one foreseen for the future LHCb DAQ, puts heavy requirements on the underlying network as all data sources from the collider will want to send to the same destinations at the same time. This may lead to an instantaneous overcommitment of the output buffers of the switches. We will present results from implementing an event building cluster based on RapidIO interconnect, focusing on the bandwidth capabilities of the technology as well as its scalability. Autors: Simaolhoda Baymani;Konstantinos Alexopoulos;Sébastien Valat; Appeared in: IEEE Transactions on Nuclear Science Publication date: Sep 2017, volume: 64, issue:9, pages: 2598 - 2605 Publisher: IEEE
» Extensive Cooperative Caching in D2D Integrated Cellular Networks
 Abstract:Device-to-device (D2D) communication is a promising supplement to cellular networks, since it provides high rate transmission without changing network infrastructure. For a D2D integrated cellular network, caching popular content (e.g., multimedia files) at a base station (BS) or a D2D device near to a requesting user not only reduces content delivery delay, but also alleviates backhaul traffic load. In order to minimize content delivery delay, in this letter, we propose an extensive cooperative caching (EC-Caching) scheme, which allows inter-BS, inter-device and between-BS-and-device cooperation in content caching. Simulation results demonstrate that the extension in degree of cooperation between the caching nodes contributes significant performance gain in terms of content delivery delay and cache hit rate, especially in populated areas. Autors: Peng Lin;Qingyang Song;Yao Yu;Abbas Jamalipour; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 2101 - 2104 Publisher: IEEE
» Extracting 3D Parametric Curves from 2D Images of Helical Objects
 Abstract:Helical objects occur in medicine, biology, cosmetics, nanotechnology, and engineering. Extracting a 3D parametric curve from a 2D image of a helical object has many practical applications, in particular being able to extract metrics such as tortuosity, frequency, and pitch. We present a method that is able to straighten the image object and derive a robust 3D helical curve from peaks in the object boundary. The algorithm has a small number of stable parameters that require little tuning, and the curve is validated against both synthetic and real-world data. The results show that the extracted 3D curve comes within close Hausdorff distance to the ground truth, and has near identical tortuosity for helical objects with a circular profile. Parameter insensitivity and robustness against high levels of image noise are demonstrated thoroughly and quantitatively. Autors: Chris G. Willcocks;Philip T. G. Jackson;Carl J. Nelson;Boguslaw Obara; Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence Publication date: Sep 2017, volume: 39, issue:9, pages: 1757 - 1769 Publisher: IEEE
» Extraction of Frequency-Dependent Characteristic Impedance and Complex Permittivity in Single-Ended and Edge-Coupled Transmission Lines Using the Calculated Series Parasitic Effects
 Abstract:This paper presents a method to obtain the characteristic impedance () and the complex permittivity () of single-ended and edge-coupled interconnects on printed circuit board (PCB) technology. For this purpose, experimentally determined propagation constant () data are used in combination with the frequency-dependent resistance () and inductance (). Due to the difficulty of directly obtaining and from measurements, closed-form equations are used to perform the corresponding calculation. In this regard, the current distribution effects are considered within the cross section of the signal traces and the ground plane. The proposal was validated for both, single-ended and edge-coupled PCB interconnects considering three cases: standard, medium-loss, and in low-loss materials. The results show that the extracted data are in agreement with values reported in material datasheets at 4 GHz. In this regard, the method is a good alternative to characterize planar transmission lines on PCB technology within the whole frequency range where the S-parameter measurements are performed. Autors: Diego M. Cortés-Hernández;Rosa J. Sánchez-Mesa;Svetlana C. Sejas-García;Reydezel Torres-Torres; Appeared in: IEEE Transactions on Microwave Theory and Techniques Publication date: Sep 2017, volume: 65, issue:9, pages: 3116 - 3122 Publisher: IEEE
» Fabrication of InGaAs-on-Insulator Substrates Using Direct Wafer-Bonding and Epitaxial Lift-Off Techniques
 Abstract:Defect less semiconductor-on-insulator (-OI) by a cost-effective and low-temperature process is strongly needed for monolithic 3-D integration. Toward this, in this paper, we present a cost-effective fabrication of the indium gallium arsenide-OI structure featuring the direct wafer bonding (DWB) and epitaxial lift-off (ELO) techniques as well as the reuse of the indium phosphide donor wafer. We systematically investigated the effects of the prepatterning of the III–V layer before DWB and surface reforming (hydrophilic) to speed up the ELO process for a fast and high-throughput process, which is essential for cost reduction. This method provides an excellent crystal quality of In0.53Ga0.47As on Si. Crystal quality of the film was evaluated using Raman spectra, and transmission electron microscope. Finally, we achieved good electrical properties of In0.53Ga0.47As-OI metal-oxide-semiconductor field-effect-transistors fabricated through the proposed DWB and ELO. Autors: Seong Kwang Kim;Jae-Phil Shim;Dae-Myeong Geum;Chang Zoo Kim;Han-Sung Kim;Jin Dong Song;Sung-Jin Choi;Dae Hwan Kim;Won Jun Choi;Hyung-Jun Kim;Dong Myong Kim;Sanghyeon Kim; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3601 - 3608 Publisher: IEEE
» Fabrication of Planar Back End of Line Compatible HfO$_x$ Complementary Resistive Switches
 Abstract:This paper presents the fabrication, together with morphological and electrical characterizations of complementary resistive switches using the nanodamascene process. The as-fabricated devices are fully embedded in an insulating oxide, opening the way for further process steps such as three-dimensional monolithic integration. Complementary resistive switches electrical performance is consistent with resistive random access memories fabricated and characterized with the same procedure that showed ratios of 100. Complementary operating voltages of and are obtained for 88 × 22 nm2 junction with a 6 nm thick HfO junction. Autors: Marina Labalette;Simon Jeannot;Serge Blonkowski;Yann Beilliard;Serge Ecoffey;Abdelkader Souifi;Dominique Drouin; Appeared in: IEEE Transactions on Nanotechnology Publication date: Sep 2017, volume: 16, issue:5, pages: 745 - 751 Publisher: IEEE
» Facet Segmentation-Based Line Segment Extraction for Large-Scale Point Clouds
 Abstract:As one of the most common features in the man-made environments, straight lines play an important role in many applications. In this paper, we present a new framework to extract line segments from large-scale point clouds. The proposed method is fast to produce results, easy for implementation and understanding, and suitable for various point cloud data. The key idea is to segment the input point cloud into a collection of facets efficiently. These facets provide sufficient information for determining linear features in the local planar region and make line segment extraction become relatively convenient. Moreover, we introduce the concept “number of false alarms” into 3-D point cloud context to filter the false positive line segment detections. We test our approach on various types of point clouds acquired from different ways. We also compared the proposed method with several other methods and provide both quantitative and visual comparison results. The experimental results show that our algorithm is efficient and effective, and produce more accurate and complete line segments than the comparative methods. To further verify the accuracy of the line segments extracted by the proposed method, we also present a line-based registration framework, which employs these line segments on point clouds registration. Autors: Yangbin Lin;Cheng Wang;Bili Chen;Dawei Zai;Jonathan Li; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 4839 - 4854 Publisher: IEEE
» Facilitating the Integration of Renewables in Latin America: The Role of Hydropower Generation and Other Energy Storage Technologies
 Abstract:It is well known that storage facilities can provide value to various electricity sectors through several services, which we group into five main classes. Autors: Rodrigo Moreno;Rafael Ferreira;Luiz Barroso;Hugh Rudnick;Eduardo Pereira; Appeared in: IEEE Power and Energy Magazine Publication date: Sep 2017, volume: 15, issue:5, pages: 68 - 80 Publisher: IEEE
» Factor Graphs for Quantum Probabilities
 Abstract:A factor-graph representation of quantum-mechanical probabilities (involving any number of measurements) is proposed. Unlike standard statistical models, the proposed representation uses auxiliary variables (state variables) that are not random variables. All joint probability distributions are marginals of some complex-valued function , and it is demonstrated how the basic concepts of quantum mechanics relate to factorizations and marginals of . Autors: Hans-Andrea Loeliger;Pascal O. Vontobel; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 5642 - 5665 Publisher: IEEE
» Falling Water, Rising Power
 Abstract:Hydropower is the production of electricity utilizing the force of falling water. Hydroelectric generators typically found in the United States range greatly in capacity from microhydro units rated between 5 kW-100 kW up to the large units at Grand Coulee Dam in Washington state, which are rated at 805 MW. The newly constructed Three Gorges Dam in China houses 32 units rated at 700 MW as well as two units rated at 50 MW to power the plant itself. Three Gorges is the world's largest hydroelectric power plant in terms of installed electrical generating capacity. Hydropower production can vary throughout the year as water supplies fluctuate. Peak hydropower generation typically occurs during the spring and summer months during snow melt and rain run-off season. Autors: Mark Skoric; Appeared in: IEEE Potentials Publication date: Sep 2017, volume: 36, issue:5, pages: 30 - 31 Publisher: IEEE
» Family of Soft-Switching Bidirectional Converters With Extended ZVS Range
 Abstract:This paper proposes a family of soft-switching bidirectional converters. In many applications, the bidirectional converters operate over a wide range of duty cycle and load variations. In the proposed converters, in order to extend the zero-voltage switching operation range, two supplemental voltage sources utilizing passive components are implemented in the auxiliary circuit. By using this method, the soft-switching features are ensured for an extensive range of the converter duty cycles. This is achieved independent of the output power value or the converter operation mode, and so, soft switching is ensured within the entire converter operating region. In these converters, all semiconductors components are soft switched, and the auxiliary circuit does not contribute to the complexity of the control circuit. Also, no extra voltage stress exists on the main switches and the voltage stress on the auxiliary switches is lower than the main switches voltage stress. In this paper, the proposed bidirectional buck/boost converter is analyzed and to confirm the feasibility of the proposed method, experimental results of a 150-W prototype converter are presented. Autors: Mohammad Reza Mohammadi;Hosein Farzanehfard; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7000 - 7008 Publisher: IEEE
» Farm Workers of the Future: Vision-Based Robotics for Broad-Acre Agriculture
 Abstract:Farmers are under growing pressure to intensify production to feed a growing population while managing environmental impact. Robotics has the potential to address these challenges by replacing large complex farm machinery with fleets of small autonomous robots. This article presents our research toward the goal of developing teams of autonomous robots that perform typical farm coverage operations. Making a large fleet of autonomous robots economical requires the use of inexpensive sensors, such as cameras for localization and obstacle avoidance. To this end, we describe a vision-based obstacle detection system that continually adapts to environmental and illumination variations and a visionassisted localization system that can guide a robot along crop rows with a complex appearance. Large fleets of robots will become time-consuming to monitor, control, and resupply. To reduce this burden, we describe a vision-based docking system for autonomously refilling liquid supplies and an interface for controlling multiple robots. Autors: David Ball;Patrick Ross;Andrew English;Peter Milani;Daniel Richards;Andrew Bate;Ben Upcroft;Gordon Wyeth;Peter Corke; Appeared in: IEEE Robotics & Automation Magazine Publication date: Sep 2017, volume: 24, issue:3, pages: 97 - 107 Publisher: IEEE
» Fascist Pigs [Book Review]
 Abstract: Autors: Nicholas G. Evans; Appeared in: IEEE Technology and Society Magazine Publication date: Sep 2017, volume: 36, issue:3, pages: 12 - 14 Publisher: IEEE
» Fast Adaptive Finite-Time Voltage Regulation Control Algorithm for a Buck Converter System
 Abstract:A new voltage regulation control algorithm is designed for the buck-type dc-dc converter system in the presence of unknown input voltage and load variations. To enhance the voltage regulation time by using the finite-time control theory, a new fast voltage regulation control algorithm is designed that can guarantee that the output voltage converges to the reference voltage in a finite time. To address the unknown input voltage and load variations, two finite-time convergent observers are designed to estimate the unknown parameters in a finite time. Finally, an adaptive finite-time control algorithm is developed. Compared with the PI control algorithm, experimental results show that the proposed algorithm has a faster regulation performance and stronger performance on load-variation rejection. Autors: Yingying Cheng;Haibo Du;Chen Yang;Zuo Wang;Jinping Wang;Yigang He; Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs Publication date: Sep 2017, volume: 64, issue:9, pages: 1082 - 1086 Publisher: IEEE
» Fast Classification for Large Polarimetric SAR Data Based on Refined Spatial-Anchor Graph
 Abstract:The graph model-based semisupervised machine learning is well established. However, its computational complexity is still high in terms of the time consumption especially for large data. In this letter, we propose a fast semisupervised classification algorithm using the recently presented spatial-anchor graph for a large polarimetric synthetic aperture radar (Pol-SAR) data, named as Fast Spatial-Anchor Graph (FSAG) based algorithm. Based on an initial superpixel segmentation on the PolSAR image, the homogenous regions are obtained. The border pixels are reassigned to the most similar superpixel according to majority voting and distance measurement. Then, feature vectors are weighted within local homogenous regions. The refined spatial-anchor graph is constructed with these regions, and the semisupervised classification is conducted. Experimental results on synthesized and real PolSAR data indicate that the proposed FSAG greatly reduces time consumption and maintains the accuracy for terrain classifications compared with state-of-the-art graph-based approaches. Autors: Hongying Liu;Shuyuan Yang;Shuiping Gou;Puhua Chen;Yikai Wang;Licheng Jiao; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1589 - 1593 Publisher: IEEE
» Fast Determination of Saddle-Node Bifurcations via Parabolic Approximations in the Infeasible Region
 Abstract:This letter presents a simple methodology to quickly obtain the saddle-node bifurcation points of power systems by first solving a sequence of power flows that ends in the infeasible region and then performing a parabolic adjustment with the results of two infeasible cases. The proposed method exploits the ability of the factored load flow procedure to converge to complex solutions well beyond the maximum loading point. Test results on benchmark cases show that the new method yields a significant reduction in the computational cost, when compared to the previous approach based on exhaustive bisection search. Autors: Catalina Gómez-Quiles;Antonio Gómez-Expósito; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 4153 - 4154 Publisher: IEEE
» Fast Energy Efficient Radix-16 Sequential Multiplier
 Abstract:We propose a new sequential multiplier design that generates the radix-16 partial products (e.g., ) as two high () and low () components, such that , , where denotes the multiplicand. The required hard multiple is generated in a preliminary cycle to the advantage of reducing the cycle time of the main iteration. Two radix-16 carry-save adders are used to generate the radix-16 accumulated partial product. The synthesis results show improved latency, power dissipation, and energy consumption over the previous relevant designs at the cost of additional silicon area, while, however, the energy-area product is also lowered. Autors: Saba Amanollahi;Ghassem Jaberipur; Appeared in: IEEE Embedded Systems Letters Publication date: Sep 2017, volume: 9, issue:3, pages: 73 - 76 Publisher: IEEE
» Fast Low-Temperature Plasma Process for the Application of Flexible Tin-Oxide-Channel Thin Film Transistors
 Abstract:In this study, we demonstrated a p-type and n-type SnO TFTs on flexible polyimide substrate. The fabricated p-type SnO TFT showed a high of and a high of . Through optimizing the oxygen plasma condition, the n-type channel TFT transfered from prime p-type channel exhibits excellent characteristics, including a high on/off current ratio of , a low threshold voltage of −0.13 V, and a very high field-effect mobility of . This proposed low-temperature oxygen plasma treatment shows the potential in simplification of TFT process that can achieve n-type and p -type TFTs under the same device process. Autors: Po-Chun Chen;Yu-Chien Chiu;Zhi-Wei Zheng;Ming-Huei Lin;Chun-Hu Cheng;Guan-Lin Liou;Hsiao-Hsuan Hsu;Hsuan-ling Kao; Appeared in: IEEE Transactions on Nanotechnology Publication date: Sep 2017, volume: 16, issue:5, pages: 876 - 879 Publisher: IEEE
» Fast Moving Horizon State Estimation for Discrete-Time Systems Using Single and Multi Iteration Descent Methods
 Abstract:Descent algorithms based on the gradient, conjugate gradient, and Newton methods are investigated to perform optimization in moving horizon state estimation for discrete-time linear and nonlinear systems. Conditions that ensure the stability of the estimation error are established for single and multi iteration schemes with a least-squares cost function that takes into account only a batch of most recent information. Simulation results show the effectiveness of the proposed approaches also in comparison with techniques based on the Kalman filter. Autors: Angelo Alessandri;Mauro Gaggero; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4499 - 4511 Publisher: IEEE
» Fast Operating Moving Coil Actuator for a Vacuum Interrupter
 Abstract:Vacuum circuit breakers are the dominant technology in medium-voltage distribution networks since they are environment friendly and maintenance free. It is a challenge to design an actuator for a vacuum circuit breaker, which achieves a high operating speed while maintaining high efficiency. A fast operating moving coil actuator for a vacuum interrupter has been developed. An analytical model of the actuator was initially developed and then simulated using a 3-D finite-element (FE) model. The model showed that the opening force was higher than the closing force due to asymmetry in the structure of the actuator, which resulted in a reluctance force component. The complete operating actuator prototype was built to avoid known problems such as contact popping, bounce, rebound, and welding. The magnetic field distribution and the static electromagnetic force on the moving coil were measured and provided a good correlation with the FE model simulation predications. The opening operation of the actuator prototype was compared for different capacitor supply voltages. A maximum velocity of 2.3 m/s was achieved when the capacitor was charged to 150 V. The actuator demonstrated successful operation at atmospheric pressure and also in a vacuum chamber. The opening time of the actuator in the vacuum was approximately 5 ms, compared to 5.5 ms at atmospheric pressure. We designed and built this actuator to illustrate that the moving coil actuator is capable of operating the vacuum circuit breaker quickly with high efficiency. Tests showed that further design optimizations for improving the operating speed and efficiency of the moving coil actuator are essential and the options have also been suggested. Autors: Xiaoze Pei;Alexander C. Smith;Roger Shuttleworth;Damian Sergio Vilchis-Rodriguez;Mike Barnes; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 931 - 940 Publisher: IEEE
» Fast Stochastic Analysis of Electromigration in Power Distribution Networks
 Abstract:A fast and stochastic analysis methodology for electromigration (EM) assessment of power distribution networks is presented in this paper. We examine the impact of variability on EM time-to-failure (TTF), considering altered current densities due to global/local process variations as well as the fundamental factors that cause the conventional EM TTF distribution. Through the novel variations-aware current density model based on Hermite polynomial chaos, we demonstrate significant margins in EM lifetime when compared with the traditional worst case approach. On the other hand, we show that the traditional approach is altogether incompetent in handling transistor-level local variations leading to significantly optimistic lifetime estimates for lower metal level interconnects of power delivery network. Subsequently, we attempt to bridge the conventional, component-level EM verification method to the system level failures, inspired by the extreme order statistics. We make use of asymptotic order models to determine the TTF for the th component failure due to EM, and demonstrate application of this approach in developing IR drop aware system-level failure criteria. Autors: Palkesh Jain;Vivek Mishra;Sachin S. Sapatnekar; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Sep 2017, volume: 25, issue:9, pages: 2512 - 2524 Publisher: IEEE
» Fast Verification of Guide-Patterns for Directed Self-Assembly Lithography
 Abstract:Guide-patterns (GPs) are critical to the construction of contacts and vias in directed self-assembly (DSA) lithography. Simulations can be used to verify GPs, but runtime is excessive. Instead, we categorize the shapes of GPs using a small number of geometric parameters. Then a verification function is built to predict whether a GP will produce the required contacts, as follows: a vector in parameter space is constructed to represent each GP in a test set; the acceptability of each GP is then assessed by DSA simulation, and each vector is tagged “good” or “bad” accordingly; next, the parameter space is deformed to convert a radial distribution into one in which the good and bad vectors can be separated by a hyper-plane, which finally becomes the verification function. We also show how to reduce the dimensionality of the parameter space by principal component analysis, and how to generalize the geometric description of GPs to allow different types of GP to be verified in a uniform fashion. The proposed GP verification is demonstrated in 10 nm technology. Autors: Seongbo Shim;Youngsoo Shin; Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Publication date: Sep 2017, volume: 36, issue:9, pages: 1522 - 1531 Publisher: IEEE
» Fast-Frequency Response Provided by DFIG-Wind Turbines and its Impact on the Grid
 Abstract:This paper presents a methodology for the analysis of frequency dynamics in large-scale power systems with high level of wind energy penetration by means of a simplified model for DFIG-based wind turbines. In addition, a virtual inertia controller version of the optimized power point tracking (OPPT) method is implemented for this kind of wind turbines, where the maximum power point tracking curve is shifted to drive variations in the active power injection as a function of both the grid frequency deviation and its time derivative. The proposed methodology integrates the model in a primary frequency control scheme to analyze the interaction with the rest of the plants in the power system. It is also proven that, under real wind conditions, the proposed version of the OPPT method allows us to smooth the wind power injected into the grid, thereby reducing frequency fluctuations. Autors: Danny Ochoa;Sergio Martinez; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 4002 - 4011 Publisher: IEEE
» Fault-Tolerant Multilevel Topology Based on Three-Phase H-Bridge Inverters for Open-End Winding Induction Motor Drives
 Abstract:In this paper, a multilevel inverter based on three-phase H-bridge inverters for an open-end winding induction motor drive is presented and its fault-tolerance capability is investigated. The multilevel topology is obtained using three wye-connected three-phase H-bridge inverters to supply open-end winding induction motors. This topology has the ability to extend the maximum voltage applied to the motor windings up to two times the dc supply voltage of the three-phase inverters. For a given induction motor voltage, the topology allows the use of dc sources with a lower voltage rating. Consequently, faster power semiconductors can be used. This multilevel topology can be directly controlled by modifying known modulation concepts, such as sinusoidal pulse width modulation (PWM). In this study, two sinusoidal PWM modulation techniques will be implemented: the level-shifted carriers (phase disposition) and the phase-shifted modulator. Fault-tolerant operation under an open-switch fault without adding any extra components and without changing the modulation strategy is also proposed, adding fault-tolerant capability to the new topology. Experimental results of this multilevel inverter in normal operation and in fault tolerant mode are presented. The obtained results confirm the fault effectiveness of the proposed multilevel topology. Autors: Vitor Fernão Pires;Daniel Foito;J. Fernando Silva; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 895 - 902 Publisher: IEEE
» Fear Not Distribution that Works [Open Letter]
 Abstract: Autors: Jefferey Dungen; Appeared in: IEEE Technology and Society Magazine Publication date: Sep 2017, volume: 36, issue:3, pages: 11 - 11 Publisher: IEEE
» Feasibility and Validation of 4-D Pulse Wave Imaging in Phantoms and In Vivo
 Abstract:Pulse wave imaging (PWI) is a noninvasive technique for tracking the propagation of the pulse wave along the arterial wall. The 3-D ultrasound imaging would aid in objectively estimating the pulse wave velocity (PWV) vector. This paper aims to introduce a novel PWV estimation method along the propagation direction, validate it in phantoms, and test its feasibility in vivo. A silicone vessel phantom consisting of a stiff and a soft segment along the longitudinal axis and a silicone vessel with a plaque were constructed. A 2-D array with a center frequency of 2.5 MHz was used. Propagation was successfully visualized in 3-D in each phantom and in vivo in six healthy subjects. In three of the healthy subjects, results were compared against conventional PWI using a linear array. PWVs were estimated in the stiff (3.42 ± 0.23 m ) and soft (2.41 ± 0.07 m ) phantom segments. Good agreement was found with the corresponding static testing values (stiff: 3.41 m and soft: 2.48 m ). PWI-derived vessel compliance values were validated with dynamic testing. Comprehensive views of pulse propagation in the plaque phantom were generated and compared against conventional PWI acquisitions. Good agreement was found in vivo between the results of 4-D PWI (4.80 ± 1.32 m ) and conventional PWI (4.28±1.20 m ). PWVs derived for all of the healthy subjects () were within the physiological range. Thus, the 4-D PWI was successfully validated in phantoms and used to image the pulse wave propagation in normal human subjects in vivo. Autors: Iason-Zacharias Apostolakis;Pierre Nauleau;Clement Papadacci;Matthew D. McGarry;Elisa E. Konofagou; Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Publication date: Sep 2017, volume: 64, issue:9, pages: 1305 - 1317 Publisher: IEEE
» Feast or Famine [From the Editor's Desk]
 Abstract:Presents the introductory editorial for this issue of the publication. Autors: Alfy Riddle; Appeared in: IEEE Microwave Magazine Publication date: Sep 2017, volume: 18, issue:6, pages: 6 - 22 Publisher: IEEE
» Features of Capacitive Displacement Sensing That Provide High-Accuracy Measurements with Reduced Manufacturing Precision
 Abstract:The capacitive displacement sensing method based on time grating employs a set of movable induction electrodes suspended with some gap width above a set of fixed excitation electrodes, and signals are obtained through electric field coupling. In this paper, we consider three features of time-grating capacitive displacement sensors that reduce the required manufacturing precision while maintaining high-accuracy measurements. First, the effect of edge roughness of the induction electrodes is suppressed by the filtering effect of the overlapping area integral method. Second, the effect of edge roughness of the excitation electrodes can be suppressed by the smoothing effect of the electric field. Third, the averaging effect of multiple induction electrodes is adopted to reduce the effect of geometric errors in the excitation electrodes. Printed circuit board manufacturing technology with a manufacturing accuracy on the order of 10 μm is selected to fabricate a prototype time-grating capacitive sensor, and a linearity of 0.005% is obtained for a single-period range of 0.8 mm. The measurement accuracy is largely independent of the manufacturing precision owing to the three aforementioned smoothing effects, which is promising for transforming the presently challenging technology of long-range displacement measurements with nanometer-scale accuracy into a conventional technology. Autors: Kai Peng;Zhicheng Yu;Xiaokang Liu;Ziran Chen;Hongji Pu; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7377 - 7386 Publisher: IEEE
» Feedback-Based Integrated Motorway Traffic Flow Control With Delay Balancing
 Abstract:The development and deployment of simple, yet efficient, coordinated and integrated control tools for motorway traffic control remains a challenge. A generic integrated feedback-based motorway traffic flow control concept is proposed in this paper. It is based on the combination and suitable extension of control algorithms and tools proposed or deployed in other studies, such as ramp metering or variable speed limit (VSL)-enabled cascade-feedback mainstream traffic flow control, and allows for consideration of multiple bottlenecks. The new controller enables coordination of ramp metering actions at a series of on-ramps, as well as integration with VSL control actions, toward a common control goal, which is bottleneck throughput maximization. While doing this, the approach considers a pre-specified (desired) balancing of the incurred delays upstream of the employed actuators, via a suitably designed knapsack problem. Despite the multitude of the offered configurations, options, and possibilities, the generic control algorithm remains simple, efficient, and suitable for field implementation. The control algorithm is demonstrated and evaluated using a validated macroscopic traffic flow model for a number of scenarios. Autors: Georgia-Roumpini Iordanidou;Ioannis Papamichail;Claudio Roncoli;Markos Papageorgiou; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Sep 2017, volume: 18, issue:9, pages: 2319 - 2329 Publisher: IEEE
» Field and Torque Calculation and Transient Analysis in Variable Reluctance Machines
 Abstract:The variable reluctance machine (VRM), also known as the switched reluctance machine, is a class of electrical machines that exhibits many interesting characteristics. However, the satisfactory analytical formulation of its working equations (torque and voltage equations) in a saturated regime is not yet completely available for covering some of its operational aspects, such as the analysis of transient state. This paper provides such equations for the general case in which a VRM operates with a pronounced level of magnetic saturation. These equations together with help of lookup tables allow online access of the instant torque on the shaft as well as the flux linkage of a phase, since the computation times are reduced to a few microseconds, whereas in a numerical approach such as the finite-element method, would take a few minutes of CPU time, which is totally inappropriate for such investigations. Autors: Bahram Amin;Moien Masoumi;Mojtaba Mirsalim; Appeared in: IEEE Transactions on Magnetics Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 9 Publisher: IEEE
» Field Modeling for Plate-Core Inductor With Significant Fringing Using Equal-Flux Contours
 Abstract:An inductor with winding sandwiched between two core plates is analyzed to model the nonuniform distribution of magnetic field. The winding is placed near the edge of the core to maximize the energy within the limited footprint such that the amount of energy stored outside the core volume is not negligible. The proportional-reluctance, equal-flux model is developed to build the contours with equal amount of flux by governing the reluctance of the flux path. The shapes of the flux lines are modeled by different functions that are guided by the finite-element simulation. The field calculated from the flux lines enables calculation of inductance, winding loss, and core loss. The inductance is used as a figure of merit to evaluate the modeling accuracy. Prototypes made of flexible circuit for inductors with different layouts are measured to verify the model. The measured inductances agree with the modeled result by less than 13% error. Autors: Han Cui;Joyce Mullenix;Roberto Massolini;Khai D. T. Ngo; Appeared in: IEEE Transactions on Magnetics Publication date: Sep 2017, volume: 53, issue:9, pages: 1 - 10 Publisher: IEEE
» Field Plate Design for Low Leakage Current in Lateral GaN Power Schottky Diodes: Role of the Pinch-off Voltage
 Abstract:In this letter, we demonstrate a general model to reduce the reverse leakage current () in high-voltage AlGaN/GaN Schottky diodes (SBDs) by engineering the pinchoff voltage () of their field plates (FPs). The maximum voltage drop at the Schottky junction () in the OFF state can be significantly decreased by reducing , which leads to a drastically diminished . We used a tri-gate architecture as means to control and, thus, , as it offers great flexibility to engineer compared with conventional schemes. of SBDs with tri-gate FPs was reduced by decreasing the width of the nanowires, which led to a very small , below 10 nA/mm under reverse biases up to 500 V, and an increase of over 800 V in soft breakdown voltage () at /mm. These results reveal the importance of in reducing ${I}_{\text {R}}$ for SBDs, and unveil the potential of tri-gate structures as FPs for power devices. Autors: Jun Ma;Dante Colao Zanuz;Elison Matioli; Appeared in: IEEE Electron Device Letters Publication date: Sep 2017, volume: 38, issue:9, pages: 1298 - 1301 Publisher: IEEE
 Abstract:Ericsson's The 5G Business Potential report [1] analyzes commercial potential offered by fifth-generation (5G) industrial technology, focusing on eight key global industries including manufacturing, public safety, financial services, health care, automotive, public transport, media and entertainment, and energy utilities. Ericsson has identified a huge opportunity for telecom operators who address industry digitalization, and they foresee a revenue potential of US\$582 billion by 2026. Compared to 2016, this represents a 34% growth in revenue. The report shows that the manufacturing and energy utilities sectors offer the strongest opportunity for revenues created or enhanced by 5G. Autors: Matthias Pätzold; Appeared in: IEEE Vehicular Technology Magazine Publication date: Sep 2017, volume: 12, issue:3, pages: 4 - 11 Publisher: IEEE
» Finding all the Lower Boundary Points in a Multistate Two-Terminal Network
 Abstract:System reliability of a multistate flow network can be computed in terms of all the lower boundary points, called d-minimal paths (-MPs). Although several algorithms have been proposed in the literature for the -MP problem, there is still room for improvement upon its solution. Here, some new results are presented to improve the solution of the problem. A simple novel algorithm is improved to solve a Diophantine system that appeared in the -MP problem. Then, an improved algorithm is proposed for the -MP problem. It is also explained how the proposed algorithm can be used in order to assess the reliability of some smart grid communication networks. We provide the complexity results and show the main algorithm to be more efficient than the existing ones in terms of execution times through some benchmark networks and a general network example. Moreover, we compare the algorithms through one thousand randomly generated test problems using the Dolan and Moré's performance profile. Autors: Majid Forghani-elahabad;Luiz Henrique Bonani; Appeared in: IEEE Transactions on Reliability Publication date: Sep 2017, volume: 66, issue:3, pages: 677 - 688 Publisher: IEEE
» Finding Related Forum Posts through Content Similarity over Intention-Based Segmentation
 Abstract:We study the problem of finding related forum posts to a post at hand. In contrast to traditional approaches for finding related documents that perform content comparisons across the content of the posts as a whole, we consider each post as a set of segments, each written with a different goal in mind. We advocate that the relatedness between two posts should be based on the similarity of their respective segments that are intended for the same goal, i.e., are conveying the same intention. This means that it is possible for the same terms to weigh differently in the relatedness score depending on the intention of the segment in which they are found. We have developed a segmentation method that by monitoring a number of text features can identify the parts of a post where significant jumps occur indicating a point where a segmentation should take place. The generated segments of all the posts are clustered to form intention clusters and then similarities across the posts are calculated through similarities across segments with the same intention. We experimentally illustrate the effectiveness and efficiency of our segmentation method and our overall approach of finding related forum posts. Autors: Dimitra Papadimitriou;Georgia Koutrika;Yannis Velegrakis;John Mylopoulos; Appeared in: IEEE Transactions on Knowledge and Data Engineering Publication date: Sep 2017, volume: 29, issue:9, pages: 1860 - 1873 Publisher: IEEE
» Finite-Horizon Energy-Efficient Scheduling With Energy Harvesting Transmitters Over Fading Channels
 Abstract:In this paper, energy-efficient transmission schemes achieving maximal throughput over a finite time interval are studied in a problem setting, including energy harvests, data arrivals, and channel variation. The goal is to express the offline optimal policy in a way that facilitates a good online solution. We express any throughput maximizing energy-efficient offline schedule (EE-TM-OFF) explicitly in terms of water levels. This allows per-slot real-time evaluation of transmit power and rate decisions, using estimates of the associated offline water levels. To compute the online power level, we construct a stochastic dynamic program that incorporates the offline optimal solution as a stochastic process. We introduce the immediate fill measure, which provides a lower bound on the efficiency of any online policy with respect to the corresponding optimal offline solution. The online algorithms obtained this way exhibit performance close to the offline optimal, not only in the long run but also in short problem horizons, deeming them suitable for practical implementations. Autors: Baran Tan Bacinoglu;Elif Uysal-Biyikoglu;Can Emre Koksal; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 6105 - 6118 Publisher: IEEE
» First-Principles Investigations of TiGe/Ge Interface and Recipes to Reduce the Contact Resistance
 Abstract:The metal–semiconductor interface is fundamental to any semiconductor device and the success of advanced technology nodes critically depends upon the minimization of the contact resistance at the interface. In this paper, we calculate the electronic structure of a metal–semiconductor interface (TiGe/Ge contact) within the framework of first-principles density functional theory simulations. We report the modulation of the Schottky barrier height with respect to the different phases of TiGe metal and different crystallographic orientations of Ge substrate. We further compute the – characteristics of the TiGe/Ge contact with nonequilibrium Green’s function formalism, using a two-terminal device configuration. The calculated transmission spectrum allows us to extract the contact resistance at the metal–semiconductor interface. Furthermore, the onset of Ohmic contact for p-doped TiGe/Ge interface is identified by studying the – characteristics as a function of increasing active carrier concentration. We find that a doping concentration of 1e21 is sufficient to transform the Schottky contact into Ohmic and thereby achieve a least possible contact resistance at the interfaces. Our paper thus provides useful physical insights into the nanoscale details of the TiGe/Ge interfaces and can guide further process development to minimize the contact resistance. Autors: Hemant Dixit;Chengyu Niu;Mark Raymond;Vimal Kamineni;Rajan K. Pandey;Anirudhha Konar;Jody Fronheiser;Adra V. Carr;Phil Oldiges;Praneet Adusumilli;Nicholas A. Lanzillo;Xin Miao;Bhagawan Sahu;Francis Benistant; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3775 - 3780 Publisher: IEEE
» Flexibility Needed: Challenges for Future Energy Storage Systems [Guest Editorial]
 Abstract:The articles in this special section focus on the technologies that will support future energy storage systems. In modern power systems, we are transitioning to an increasing penetration of massive low-cost wind and solar generation, which will require indispensable system flexibility for balancing requirements to maintain system performance. The existing actors have limited technical capabilities to provide the needed flexibility, and new alternatives are required. The flexibility providers are diverse and being assessed extensively, with a clear sense of urgency. Autors: Hugh Rudnick;Luiz Barroso; Appeared in: IEEE Power and Energy Magazine Publication date: Sep 2017, volume: 15, issue:5, pages: 12 - 19 Publisher: IEEE
» Flexible Power Regulation and Current-Limited Control of the Grid-Connected Inverter Under Unbalanced Grid Voltage Faults
 Abstract:The grid-connected inverters may experience excessive current stress in case of unbalanced grid voltage fault ride through (FRT), which significantly affects the reliability of the power supply system. In order to solve the problem, the inherent mechanisms of the excessive current phenomenon with the conventional FRT solutions are discussed. The quantitative analysis of three-phase current peak values is conducted and a novel current-limited control strategy is proposed to achieve the flexible active and reactive power regulation and successful FRT in a safe current operation area with the aim of improving the system reliability under grid faults. Finally, the simulation and experiments of traditional and proposed FRT solutions are carried out. The results verify the effectiveness of the proposed method. Autors: Xiaoqiang Guo;Wenzhao Liu;Zhigang Lu; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7425 - 7432 Publisher: IEEE
» Fly the electric skies
 Abstract:When you first sit in the cockpit of an electric-powered airplane, you see nothing out of the ordinary. However, touch the Start button and it strikes you immediately: an eerie silence. There is no roar, no engine vibration, just the hum of electricity and the soft whoosh of the propeller. You can converse easily with the person in the next seat, without headphones. The silence is a boon to both those in the cockpit and those on the ground below. Autors: George Bye; Appeared in: IEEE Spectrum Publication date: Sep 2017, volume: 54, issue:9, pages: 26 - 31 Publisher: IEEE
» Flying cell towers to the rescue
 Abstract:YOU'VE JUST SETTLED DOWN on the couch when a sudden jolt rattles you so hard that you spill hot coffee in your lap. The walls of your home split and collapse, pinning you beneath a section of roofing. Then the motion stops. Heart pounding, you reach for the smartphone in your pocket, but when you try to call for help, there’s no service. Because the earthquake has demolished the nearest cell tower, first responders are forced to rely on outdated radios and networks as they search the rubble for survivors. The devices carried by police officers can't communicate with those used by firefighters. Walkie-talkies work only at short range. No wonder several homes are searched twice while yours is overlooked. Autors: Kamesh Namuduri; Appeared in: IEEE Spectrum Publication date: Sep 2017, volume: 54, issue:9, pages: 38 - 43 Publisher: IEEE
» Fog Vehicular Computing: Augmentation of Fog Computing Using Vehicular Cloud Computing
 Abstract:Fog computing has emerged as a promising solution for accommodating the surge of mobile traffic and reducing latency, both known to be inherent problems of cloud computing. Fog services, including computation, storage, and networking, are hosted in the vicinity of end users (edge of the network), and, as a result, reliable access is provisioned to delay-sensitive mobile applications. However, in some cases, the fog computing capacity is overwhelmed by the growing number of demands from patrons, particularly during peak hours, and this can subsequently result in acute performance degradation. In this article, we address this problem by proposing a new concept called fog vehicular computing (FVC) to augment the computation and storage power of fog computing. We also design a comprehensive architecture for FVC and present a number of salient applications. The result of implementation clearly shows the effectiveness of the proposed architecture. Finally, some open issues and envisioned directions are discussed for future research in the context of FVC. Autors: Mehdi Sookhak;F. Richard Yu;Ying He;Hamid Talebian;Nader Sohrabi Safa;Nan Zhao;Muhammad Khurram Khan;Neeraj Kumar; Appeared in: IEEE Vehicular Technology Magazine Publication date: Sep 2017, volume: 12, issue:3, pages: 55 - 64 Publisher: IEEE
» Food Intake Detection Using Ultrasonic Doppler Sonar
 Abstract:Reliable, user-friendly and convenient sensing is highly desirable when the continuous monitoring of food intake is necessary. In this paper, food intake monitoring was during the processes of chewing and swallowing. Acoustic Doppler sonar (ADS) detected chewing and swallowing events that were non-contact and free from acoustic interference. When a 40 kHz ultrasonic beam was focused on the lower jaw and neck, movements of the chin and neck cause Doppler frequency shifts and an amplitude envelope modulation of ultrasonic signals. Hence, it was possible to detect chewing and swallowing events using Doppler frequency shifts in the received ultrasound signals. To prevent suspicious chew events caused by talking from being recognized as food intake events, the log-filter bank energy of the voice band was also taken into consideration. Automatic detection of chewing and swallowing events was achieved via an artificial neural network. The experimental results showed that the proposed ADS-based food intake detection method yielded promising results with maximum recognition rates of 91.4% and 78.4% for chewing and swallowing, respectively. As a result, it was confirmed that the proposed food intake detection method using ultrasonic Doppler yielded high rates of recognition without discomfort to the user from continuous skin contact. Autors: Ki-Seung Lee; Appeared in: IEEE Sensors Journal Publication date: Sep 2017, volume: 17, issue:18, pages: 6056 - 6068 Publisher: IEEE
» Forest Change Detection in Incomplete Satellite Images With Deep Neural Networks
 Abstract:Land cover change monitoring is an important task from the perspective of regional resource monitoring, disaster management, land development, and environmental planning. In this paper, we analyze imagery data from remote sensing satellites to detect forest cover changes over a period of 29 years (1987–2015). Since the original data are severely incomplete and contaminated with artifacts, we first devise a spatiotemporal inpainting mechanism to recover the missing surface reflectance information. The spatial filling process makes use of the available data of the nearby temporal instances followed by a sparse encoding-based reconstruction. We formulate the change detection task as a region classification problem. We build a multiresolution profile (MRP) of the target area and generate a candidate set of bounding-box proposals that enclose potential change regions. In contrast to existing methods that use handcrafted features, we automatically learn region representations using a deep neural network in a data-driven fashion. Based on these highly discriminative representations, we determine forest changes and predict their onset and offset timings by labeling the candidate set of proposals. Our approach achieves the state-of-the-art average patch classification rate of 91.6% (an improvement of ~16%) and the mean onset/offset prediction error of 4.9 months (an error reduction of five months) compared with a strong baseline. We also qualitatively analyze the detected changes in the unlabeled image regions, which demonstrate that the proposed forest change detection approach is scalable to new regions. Autors: Salman H. Khan;Xuming He;Fatih Porikli;Mohammed Bennamoun; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 5407 - 5423 Publisher: IEEE
» Forward and Backward Extended Prony (FBEP) Method for Power System Small-Signal Stability Analysis
 Abstract:The performance of the Forward and Backward Extended Prony (FBEP) method on power system small-signal stability analysis is investigated in this paper. The effectiveness of the FBEP method in identifying system eigenvalues from the output signal is validated by experiments on a test system model. Using a four-machine-two-area power system model the estimation of the dominant modes contained in oscillatory signals given by the FBEP method is compared with that given by the SVD-TLS method, Trudnowski's algorithm, and the Prony with stepwise regression method. The multi-signal analysis and sliding window analysis using the FBEP method are also studied. Autors: Shuang Zhao;Kenneth A. Loparo; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3618 - 3626 Publisher: IEEE
» Foundations of a Bicoprime Factorization Theory
 Abstract:Bicoprime factorizations (BCFs) are a generalization of the well known coprime factorizations commonly used in control theory. However they have received negligible attention from the academic community so far. This technical note lays the foundations of a BCF theory. The theory is built from the ground up, starting with the basic characteristics of such factorizations before moving on to state space parameterizations of BCFs and internal stability. Some advantages of BCFs are outlined including the possibility of reduced dimension internal stability tests. An uncertainty structure induced by BCFs is also examined and the associated robust stability analysis tests provided. In multiple instances it is shown how coprime factor results have their roots in the more abstract, and more general, BCFs. Autors: Mihalis Tsiakkas;Alexander Lanzon; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4598 - 4603 Publisher: IEEE
» Frequency Reconfigurable Multiband Handset Antenna Based on a Multichannel Transceiver
 Abstract:The upcoming standards of wireless communications result in additional and more stringent requirements for antennas in mobile phones. In this paper, we present a frequency-reconfigurable antenna that could potentially be suited for future mobile devices. Frequency reconfigurability is achieved through a cluster of mutually coupled antenna elements that is excited with frequency-dependent weights using a multichannel transceiver. We report a mobile handset antenna cluster measuring 15 15 1.6 mm3 that covers the frequency bands of 1.7–2.7, 3.3–4.5, and 5.475–6.425 GHz with an antenna efficiency better than 90%. The operation of the antenna cluster is experimentally verified by feeding all the antenna elements with proper weights using tailor-made power splitters that represent a multichannel transceiver with adjustable amplitude and phase in each branch. The results obtained with the feed networks suggest the feasibility of the reconfigurability concept and pave way for codesign of the antenna and the transceiver. Autors: Jari-Matti Hannula;Tapio Saarinen;Jari Holopainen;Ville Viikari; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4452 - 4460 Publisher: IEEE
» From the editors' desk
 Abstract:Presents the introductory editorial for this issue of the publication. Autors: Ed Cherney;Robert Fleming; Appeared in: IEEE Electrical Insulation Magazine Publication date: Sep 2017, volume: 33, issue:5, pages: 7 - 8 Publisher: IEEE
» Full 2-D Submillimeter-Wave Frequency Scanning Array
 Abstract:A 2-D frequency scanning array operating in the 220–320-GHz frequency band is presented. The array is composed of 64 open-ended rectangular waveguides arranged in an configuration. The feeding circuit comprises two waveguide-based phase shifting networks, which provides the required phase shift between adjacent radiating elements when the working frequency is modified. The array was manufactured over brass sheets through a mechanical procedure and experimentally characterized, providing beam steering along a space region while the working frequency is swept between 220 and 320 GHz, with a maximum −10-dB secondary lobe level and a measured 17-dBi gain at 275 GHz. Autors: René Camblor;Samuel Ver Hoeye;Miguel Fernández;Carlos Vázquez Antuña;Fernando Las-Heras; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4486 - 4494 Publisher: IEEE
» Fully Coupled Multiphysics Simulation of Crosstalk Effect in Bipolar Resistive Random Access Memory
 Abstract:A versatile multiphysics simulation packet for investigating different resistive random acces memories (RRAMs) is developed in this paper. Heat transfer, electrical conduction, and ion migration in such heterogeneous structure are all taken into consideration. Three fully coupled partial differential equations are solved using our self-developed finite-difference algorithm, where Scharfetter–Gummel method is adopted to simulate ion migration with fast convergence achieved. This packet is validated in comparison with the commercial software based on the finite-element method. With its implementation, complete and clear pictures for crosstalk effect in vertically integrated RRAM are captured and compared, where the effects of key physical and geometrical factors are characterized and understood. Some useful suggestions to mitigate its unfavorable influences are given. Autors: Shichao Li;Wenchao Chen;Yandong Luo;Jun Hu;Pingqi Gao;Jichun Ye;Kai Kang;Hongsheng Chen;Erping Li;Wen-Yan Yin; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3647 - 3653 Publisher: IEEE
» Fully Integrated Fluorescence Biosensors On-Chip Employing Multi-Functional Nanoplasmonic Optical Structures in CMOS
 Abstract:Integrated optical system-on-chip in silicon operating in the visible range can have a tremendous impact on enabling new applications in sensing and imaging through the ultra-miniaturization of complex optical instrumentation. CMOS technology has allowed an integration of optical detection circuitry for image sensors with massively large number of pixels. In this paper, we focus on techniques to realize complex optical-field processing elements inside CMOS by exploiting optical interaction with sub-wavelength metal nanostructures realized in the electrical interconnects layers, whose feature sizes are now in the sub-100-nm range. In particular, we present a fully integrated fluorescence-based bio-molecular sensor in 65-nm CMOS with integrated nanoplasmonic waveguide-based filters capable of more than 50 dB of rejection ratio across a wide range of incident angles. Co-designed with the integrated photo-detection circuitry, capacitive TIAs, and correlated double-sampling circuitry, the sensor is capable of detecting 48 zeptomoles of quantum dots on the surface with 52 fA of photodetector current with a fluorescence/excitation ratio of nearly −62 dB without any post-fabrication, external optical filters, lenses, or collimators. The ability to integrate complex nanoplasmonic metal structures with unique optical properties in CMOS with no post-processing creates the opportunity to enable large multiplexed assays on a single chip and a wide variety of applications, from in vitro to in vivo. Autors: Lingyu Hong;Hao Li;Haw Yang;Kaushik Sengupta; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Sep 2017, volume: 52, issue:9, pages: 2388 - 2406 Publisher: IEEE
» Fusion of Deep Convolutional Neural Networks for Land Cover Classification of High-Resolution Imagery
 Abstract:Deep convolutional neural networks (DCNNs) have recently emerged as the highest performing approach for a number of image classification applications, including automated land cover classification of high-resolution remote-sensing imagery. In this letter, we investigate a variety of fusion techniques to blend multiple DCNN land cover classifiers into a single aggregate classifier. While feature-level fusion is widely used with deep neural networks, our approach instead focuses on fusion at the classification/information level. Herein, we train three different DCNNs: CaffeNet, GoogLeNet, and ResNet50. The effectiveness of various information fusion methods, including voting, weighted averages, and fuzzy integrals, is then evaluated. In particular, we used DCNN cross-validation results for the input densities of fuzzy integrals followed by evolutionary optimization. This novel approach produces the state-of-the-art classification results up to 99.3% for the UC Merced data set and the 99.2% for the RSD data set. Autors: Grant J. Scott;Richard A. Marcum;Curt H. Davis;Tyler W. Nivin; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1638 - 1642 Publisher: IEEE
» Fuzzy Logic Based Adaptive Droop Control in Multiterminal HVDC for Wind Power Integration
 Abstract:Following a converter outage in a Multiterminal dc (MTDC) for offshore wind farm integration, the conventional droop control shares the power mismatch to minimize the impact on the wind power generation with a fixed droop coefficient; however, it may easily lead to the converter overloading and large dc voltage deviation. The paper proposes a fuzzy logic based adaptive droop controller, which utilizes the available power capacity of the converters to update the droop coefficient. It can make a compromise between the dc voltage deviation and the power sharing. Furthermore, the impact of the droop coefficient change on the stability of the MTDC grid is analyzed, and the effect of the dc-bus capacitor on the system dynamic is identified. The stability region is determined through the eigenvalue analysis. Time-domain simulations are conducted to compare the control strategy proposed with the conventional one. It has been proved that the adaptive control scheme can constantly track dynamic behaviors of the converters, and exhibit desirable response under different outage scenarios. Autors: Xia Chen;Long Wang;Haishun Sun;Yin Chen; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 1200 - 1208 Publisher: IEEE
» GALLOP: GlobAL Feature Fused LOcation Prediction for Different Check-in Scenarios
 Abstract:Location prediction is widely used to forecast users’ next place to visit based on his/her mobility logs. It is an essential problem in location data processing, invaluable for surveillance, business, and personal applications. It is very challenging due to the sparsity issues of check-in data. An often ignored problem in recent studies is the variety across different check-in scenarios, which is becoming more urgent due to the increasing availability of more location check-in applications. In this paper, we propose a new feature fusion based prediction approach, GALLOP, i.e., GlobAL feature fused LOcation Prediction for different check-in scenarios. Based on the carefully designed feature extraction methods, we utilize a novel combined prediction framework. Specifically, we set out to utilize the density estimation model to profile geographical features, i.e., context information, the factorization method to extract collaborative information, and a graph structure to extract location transition patterns of users’ temporal check-in sequence, i.e., content information. An empirical study on three different check-in datasets demonstrates impressive robustness and improvement of the proposed approach. Autors: Yuxing Han;Junjie Yao;Xuemin Lin;Liping Wang; Appeared in: IEEE Transactions on Knowledge and Data Engineering Publication date: Sep 2017, volume: 29, issue:9, pages: 1874 - 1887 Publisher: IEEE
» Game Factors Influencing Players to Continue Playing Online Pets
 Abstract:Online pet games emphasize the enjoyment of raising a pet, social interaction, and expression of the personality. Players often obtain a sense of satisfaction and develop companionship with their pets. However, the question pertinent to why people continue playing with online pets is still unclear. The answer of this question can help developers improve game designs. The flow experience is a factor contributing to players’ willingness to engage in a gaming activity. Therefore, the purpose of this study is to adopt the concept of flow to help understand why people enjoy playing online pet games. In this study, the authors analyzed flow factors and identified crucial game elements that might elicit a flow experience by means of a questionnaire survey. A total of 180 valid questionnaires were collected, and the results demonstrated that role playing is an important flow factor for online pet games. In addition, social interaction, personality design, and creativity behavior are crucial game elements contributing to players’ willingness to continue playing with online pets. Autors: Ding-Bang Luh;Elena Carolina Li;Chia-Chen Dai; Appeared in: IEEE Transactions on Computational Intelligence and AI in Games Publication date: Sep 2017, volume: 9, issue:3, pages: 267 - 276 Publisher: IEEE
» Gamesman Problems [Gamesman Problems]
 Abstract: Autors: Athanasios Kakarountas; Appeared in: IEEE Potentials Publication date: Sep 2017, volume: 36, issue:5, pages: 48 - 48 Publisher: IEEE
» Gamesman Solutions [Gamesman Solutions]
 Abstract: Autors: Athanasios Kakarountas; Appeared in: IEEE Potentials Publication date: Sep 2017, volume: 36, issue:5, pages: 5 - 5 Publisher: IEEE
» Gate Leakage Mechanisms in AlInN/GaN and AlGaN/GaN MIS-HEMTs and Its Modeling
 Abstract:Gate leakage mechanisms in AlInN/GaN and AlGaN/GaN metal insulator semiconductor high-electron-mobility transistors (MIS-HEMTs) with SiNx as gate dielectric have been investigated. It is found that the conduction in the reverse gate bias is due to Poole-Frenkel emission for both MIS-HEMTs. The dominant conduction mechanism in low to medium forward bias is trap-assisted tunneling while it is Fowler–Nordheim tunneling at high forward bias. However, conduction near zero gate bias is dominated by defect-assisted tunneling for both sets of MIS-HEMTs. The gate leakage current is primarily dependent on the properties of the gate dielectric material and dielectric/ semiconductor interface rather than the barrier layer. A model is proposed for the gate leakage current in GaN-based MIS-HEMTs, and the method to extract the related model parameters is also presented in this paper. The proposed gate current model matches well with the experimental results for both AlInN/GaN and AlGaN/GaN MIS-HEMTs over a wide range of gate bias and measurement temperature. Autors: Gourab Dutta;Nandita DasGupta;Amitava DasGupta; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3609 - 3615 Publisher: IEEE
» Gaussian Pyramid: Comparative Analysis of Hardware Architectures
 Abstract:This paper addresses a comparison of architectures for the hardware implementation of Gaussian image pyramids. Main differences between architectural choices are in the sensor front-end. One side is for architectures consisting of a conventional sensor that delivers digital images and which is followed by digital processors. The other side is for architectures employing a non-conventional sensor with per-pixel embedded preprocessing structures for Gaussian spatial filtering. This later choice belongs to the general category of “artificial retina” sensors which have been for long claimed as potentially advantageous for enhancing throughput and reducing energy consumption of vision systems. These advantages are very important in the internet of things context, where imaging systems are constantly exchanging information. This paper attempts to quantify these potential advantages within a design space in which the degrees of freedom are the number and type of ADCs, single-slope, SAR, cyclic, , and pipeline, and the number of digital processors. Results show that speed and energy advantages of preprocessing sensors are not granted by default and are only realized through proper architectural design. The methodology presented for the comparison between focal-plane and digital approaches is a useful tool for imager design, allowing for the assessment of focal-plane processing advantages. Autors: Fernanda D. V. R. Oliveira;José Gabriel R. C. Gomes;Jorge Fernández-Berni;Ricardo Carmona-Galán;Rocío del Río;Ángel Rodríguez-Vázquez; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Sep 2017, volume: 64, issue:9, pages: 2308 - 2321 Publisher: IEEE
» Gene-Sequencing-Based Indoor Localization in Distributed Antenna System
 Abstract:In the indoor distributed antenna system (DAS), base station transmits signals with even power via the distributed antennas. Thus, single reference signal received power (RSRP) from the receiver will result in accurate localization. In response to this compelling problem, we utilize the pedestrian dead reckoning, which is based on consecutive signals in collected RSRP sequences as the template sequences, to achieve high-performance location estimation. Specifically, the main idea of the proposed localization algorithm is calculating the correlation between the on-site sequence and each pre-constructed template sequence, which is labeled with human movement coordinates. Then, the prediction location is considered as the template sequence label that is with the largest approximation to the on-site sequence. Experiments are conducted with real time division long-term evolution signals in indoor DAS, and the corresponding experimental results demonstrate that the proposed approach can not only solve the problem of positioning in DAS, but also provide satisfactory localization accuracy. Autors: Chengke Liu;Zengshan Tian;Mu Zhou;Xiaolong Yang; Appeared in: IEEE Sensors Journal Publication date: Sep 2017, volume: 17, issue:18, pages: 6019 - 6028 Publisher: IEEE
» Generalized DTC Strategy for Multilevel Inverter Fed IPMSMs With Constant Inverter Switching Frequency and Reduced Torque Ripples
 Abstract:This paper proposes a generalized direct torque control (DTC) strategy for multilevel inverter fed DTC (MLI-DTC) drives. By using a simple voltage vector decomposition technique, the proposed method is compatible with inverters possessing any number of voltage levels. Consequently, voltage vectors are applied in a similar way as in the case of a two-level inverter fed DTC. A constant inverter switching frequency is imposed in the proposed method by using a torque regulator in place of the traditional torque hysteresis controller, which enables the application of two voltage vectors within one switching cycle. This also contributes to reduce the torque and flux ripples. Detailed design guidelines for the proposed torque regulator are provided. Experimental results obtained with a three-level neutral point clamped inverter show that the proposed MLI-DTC drive operates with low, constant switching frequency while alleviating torque and flux ripples under all operating conditions. Comparative study with a prior art and parametric sensitivity analysis are also presented to verify the effectiveness and robustness of the proposed MLI-DTC method. Autors: Deepu Mohan;Xinan Zhang;Gilbert Hock Beng Foo; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 1031 - 1041 Publisher: IEEE
» Generalized MGF of Beckmann Fading With Applications to Wireless Communications Performance Analysis
» Generalized Pyramid Codes for Versioned Data in Distributed Storage Networks
 Abstract:A distributed storage framework called sparsity exploiting coding (SEC) was recently proposed for storing multiple versions of data object, wherein the objects are stored in a differential manner in order to reduce the I/O reads when retrieving multiple versions. It was shown that the design of erasure codes for the SEC framework requires Cauchy-matrix-based maximum distance separable (MDS) codes, which, however, do not enjoy the locally repairable property during the repair process. In this letter, we study the suitability of generalized pyramid codes (GPCs), a well-known class of locally repairable codes, to the SEC framework, and analyze their capability to retrieve multiple versions with few I/O reads. We show that GPCs can retrieve correlated multiple versions with fewer I/O reads than the overall object size, however, requiring more I/O reads than that by Cauchy-matrix-based MDS codes. This penalty in the I/O reads comes at the advantage of availing the locally repairable property in the SEC framework. We also show that GPCs require fewer I/O reads than the optimal locally repairable codes, in some cases. Autors: J. Harshan; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 1921 - 1924 Publisher: IEEE
» Generalized Shift-Map Codes and Their Decoding Using an Iterative Algorithm
 Abstract:This letter investigates an iterative algorithm for decoding analog error-correcting codes. First, the shift-map code, one of the widely studied analog codes, is generalized to yield a new family of codes with a more flexible tradeoff between errors at low and high signal-to-noise ratios. Then, an iterative decoding algorithm for the generalized shift-map codes is derived from a message-passing process on a sparse factor graph. Numerical simulations demonstrate that the proposed algorithm decodes generalized shift-map codes following a small number of iterations. Combined with the efficient decoding algorithm, the flexibility of the generalized shift-map codes will enhance the applicability of analog error-correcting codes. Autors: Yongseok Yoo; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 1909 - 1912 Publisher: IEEE
» Generation of 22.7-fs 2.8-nJ Pulses From an Erbium-Doped All-Fiber Laser Via Single-Stage Soliton Compression
 Abstract:We have demonstrated experimentally that few-cycle pulses can be achieved from an Er-doped fiber laser via single-stage soliton compression. Adopting negative prechirp amplification is to avoid the high-energy pulse break-up and increase the spectral width. Through optimizing the fiber length and pulse energy in different parts of the fiber laser system, the generated pulse can be as short as 22.7 fs, which is about four cycle duration at 1550 nm. The average power is up to 120 mW with the corresponding pulse energy of 2.8 nJ. Numerical simulation has been carried out to illustrate the dynamic of pulse prechirp, amplification, and compression. Autors: Hao Luo;Li Zhan;Liang Zhang;Zhiqiang Wang;Caixia Gao;Xiao Fang; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:17, pages: 3780 - 3784 Publisher: IEEE
» Generic Dynamic Models for Modeling Wind Power Plants and Other Renewable Technologies in Large-Scale Power System Studies
 Abstract:With the tremendous growth of wind power worldwide in the past decade, there has been an equally great demand for simplified, standard, and publicly available models for simulating wind power generators in commercially available power system simulation tools for stability analysis. Several efforts have been on the way to meet this need. The Western Electricity Coordinating Council's Renewable Energy Modeling Task Force has successfully achieved this goal and more recently has been working on expanding these models to include the ability to model complex plants, energy storage, and frequency response capabilities. This paper presents an account of these latest developments. Autors: Pouyan Pourbeik;Juan J. Sanchez-Gasca;Jayapalan Senthil;James D. Weber;Pouya Sajjad Zadehkhost;Yuriy Kazachkov;Spencer Tacke;Jun Wen;Abraham Ellis; Appeared in: IEEE Transactions on Energy Conversion Publication date: Sep 2017, volume: 32, issue:3, pages: 1108 - 1116 Publisher: IEEE
» GfcLLL: A Greedy Selection-Based Approach for Fixed-Complexity LLL Reduction
 Abstract:The LLL lattice reduction has been widely used to decrease the bit error rate (BER) of the Babai point, but its running time varies much from matrix to matrix. To address this problem, some fixed-complexity LLL reductions (FCLLL) have been proposed. In this letter, we propose two greedy selection-based FCLLL algorithms: GfcLLL(1) and GfcLLL(2). Simulations show that both of them give Babai points with lower BER in similar or much shorter CPU time than existing ones. Autors: Jinming Wen;Xiao-Wen Chang; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 1965 - 1968 Publisher: IEEE
» Global Chartwise Feedback Linearization of the Quadcopter With a Thrust Positivity Preserving Dynamic Extension
 Abstract:We propose a new dynamic extension of the thrust variable in the quadcopter dynamics that preserves the positive sign of the thrust. This extension not only eliminates the positive sign constraint on the thrust variable, but also leads to global chartwise feedback linearization of the quadcopter dynamics. For the latter, an atlas is first constructed on the entire state space of the quadcopter and then the dynamically extended quadcopter system is transformed to a 14-dimensional linear controllable system on each chart in the atlas. Based on the chartwise dynamic feedback linearization, a global tracking strategy is proposed for the quadcopter and its excellent performance is demonstrated with a simulation. Autors: Dong Eui Chang;Yongsoon Eun; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4747 - 4752 Publisher: IEEE
» Glucose Monitoring in Individuals With Diabetes Using a Long-Term Implanted Sensor/Telemetry System and Model
 Abstract:Objective: The use of a fully implanted first-generation prototype sensor/telemetry system is described for long-term monitoring of subcutaneous tissue glucose in a small cohort of people with diabetes. Methods: Sensors are based on a membrane containing immobilized glucose oxidase and catalase coupled to oxygen electrodes and a telemetry system, integrated as an implant. The devices remained implanted for up to 180 days, with signals transmitted every 2 min to external receivers. Results: The data include signal recordings from glucose clamps and spontaneous glucose excursions, matched, respectively, to reference blood glucose and finger-stick values. The sensor signals indicate dynamic tissue glucose, for which there is no independent standard, and a model describing the relationship between blood glucose and the signal is, therefore, included. The values of all model parameters have been estimated, including the permeability of adjacent tissues to glucose, and equated to conventional mass transfer parameters. As a group, the sensor calibration varied randomly at an average rate of −2.6%/week. Statistical correlation indicated strong association between the sensor signals and reference glucose values. Conclusion: Continuous long-term glucose monitoring in individuals with diabetes is feasible with this system. Significance: All therapies for diabetes are based on glucose control, and therefore, require glucose monitoring. This fully implanted long-term sensor/telemetry system may facilitate a new era of management of the disease. Autors: Joseph Y. Lucisano;Timothy L. Routh;Joe T. Lin;David A. Gough; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Sep 2017, volume: 64, issue:9, pages: 1982 - 1993 Publisher: IEEE
» Go ?Get Chipped?: A Brief Overview of Non-Medical Implants between 1997-2013 (Part 1)
 Abstract: Autors: Katina Michael; Appeared in: IEEE Technology and Society Magazine Publication date: Sep 2017, volume: 36, issue:3, pages: 6 - 9 Publisher: IEEE
» GOFP: A Geometric-Optical Model for Forest Plantations
 Abstract:Geometric-optical (GO) model suitable for forest plantation (GOFP) is a GO model for forest plantations at the stand level developed in this study based on a four-scale GO model a Geometric-Optical Model for Sloping Terrains-II (GOST2), which simulates the bidirectional reflectance distribution function (BRDF) for natural forest canopies. In most previous GO models, tree distributions are often assumed to meet the Poisson or Neyman model in a forest; therefore, these models are suitable for simulating BRDF for natural forest canopies. However, in forest plantations, tree distributions are proven to meet the hypergeometric model rather than the Poisson or Neyman model at the stand level. GOFP, in which the tree distributions are described using the hypergeometric model, is proposed to simulate the bidirectional reflectance factor (BRF) of forest plantations at the stand level. The area ratios of the four scene components (sunlit foliage, sunlit ground, shaded foliage, and shaded ground) of GOFP compare well with those simulated by a 3-D canopy visualization technique. A comparison is also made against discrete anisotropic radiative transfer, showing that GOFP has the ability to simulate BRF of forest plantations. Another comparison is made against operational land imager and Moderate Resolution Imaging Spectroradiometer surface reflectance, showing that GOFP with the hypergeometric model outperforms GOST2 with the Poisson and Neyman models. The results further show that the differences in BRFs between GOFP and GOST2 pronouncedly increase with the difference between the reflectance of sunlit foliage () and the reflectance of sunlit ground (), as well as the distances among trees and the number of crowns in a forest plantation, suggesting that GOFP significantly outperforms GOST2 for simulating BRF - f forest plantations. Autors: Jun Geng;Jing M. Chen;Weiliang Fan;Lili Tu;Qingjiu Tian;Ranran Yang;Yanjun Yang;Lei Wang;Chunguang Lv;Shengbiao Wu; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 5230 - 5241 Publisher: IEEE
» Going Cooler With Timing-Constrained TeSHoP: A Temperature Sensing-Based Hotspot-Driven Placement Technique for FPGAs
 Abstract:The continuous shrinking of the feature size in CMOS technology has significantly increased the power densities of integrated circuits, leading to severe temperature issues. However, the previous offline simulation-based thermal optimization works cast large deviations with the reality, while online sensing-based thermal managements usually incur significant performance overhead. Therefore, it is crucial to propose a method that could achieve fine-grained optimization with accurate temperature profiles. In this paper, we propose a timing-constraint temperature sensing-based hotspot-driven placement technique for field-programmable gate arrays (FPGAs). The hotspot optimization issue is modeled as a hyper minimum bipartite matching problem and is solved by a place adjustment with the input of an online sensed temperature profile. We propose an open-source/commercial hybrid design flow to implement the whole optimization in Xilinx Virtex-6 FPGA. Experimental results demonstrate a significant reduction in peak temperature and a great improvement on thermal uniformity, with slight performance overhead under timing constraints. Autors: Weina Lu;Yu Hu;Jing Ye;Xiaowei Li; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Sep 2017, volume: 25, issue:9, pages: 2525 - 2537 Publisher: IEEE
» GPS-Disciplined Analog-to-Digital Converter for Phasor Measurement Applications
 Abstract:This paper presents a data acquisition unit which synchronously samples multiple channels in a manner such that the time of day at which each sample is taken is known. This allows measurements taken at multiple locations to be compared with confidence. The intended application is wide area electrical power system measurements, in particular phasor measurement units (PMUs). The novelty of the authors’ design is the application of an open hardware development platform to discipline a commodity analog-to-digital converter (ADC) to a broadcast time signal, usually but not exclusively GPS. The methodology used creates a driver layer for the ADC to achieve real-time sampling in a nonpreemptive Linux environment. The use of open hardware and software addresses the need for a transparent instrument for use in research and development of PMU technology. Through a choice of either a software or hardware phase-locked loop, the ADC is controlled to acquire exactly 256 samples per nominal power system cycle (i.e., 50/60 Hz), precisely time synchronized to GPS, at 16-b resolution and 94.2-dB SNR. The design of a printed circuit board expansion board featuring all necessary components is provided. The performance of the system is evaluated. Interoperability and data exchange with other systems is achieved by use of open schemas and communication protocols. This allows rapid integration with popular numerical simulation environments. Autors: Xiaodong Zhao;David M. Laverty;Adrian McKernan;D. John Morrow;Kieran McLaughlin;Sakir Sezer; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Sep 2017, volume: 66, issue:9, pages: 2349 - 2357 Publisher: IEEE
» GPU Parallel Implementation of Isometric Mapping for Hyperspectral Classification
 Abstract:Manifold learning algorithms such as the isometric mapping (ISOMAP) algorithm have been widely used in the analysis of hyperspectral images (HSIs), for both visualization and dimension reduction. As advanced versions of the traditional linear projection techniques, the manifold learning algorithms find the low-dimensional feature representation by nonlinear mapping, which can better preserve the local structure of the original data and thus benefit the data analysis. However, the high computational complexity of the manifold learning algorithms hinders their application in HSI processing. Although there are a few parallel implementations of manifold learning approaches that are available in the remote sensing community, they have not been designed to accelerate the eigen-decomposition process, which is actually the most time-consuming part of the manifold learning algorithms. In this letter, as a case study, we discuss the graphics processing unit parallel implementation of the ISOMAP algorithm. In particular, we focus on the eigen-decomposition process and verify the applicability of the proposed method by validating the embedding vectors and the subsequent classification accuracies. The experimental results obtained on different HSI data sets show an excellent speedup performance and consistent classification accuracy compared with the serial implementation. Autors: Wan Li;Liangpei Zhang;Lefei Zhang;Bo Du; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1532 - 1536 Publisher: IEEE
» Graph Codes for Distributed Instant Message Collection in an Arbitrary Noisy Broadcast Network
 Abstract:We consider the problem of minimizing the number of broadcasts for collecting all sensor measurements at a sink node in a noisy broadcast sensor network. Focusing first on arbitrary network topologies, we provide: 1) fundamental limits on the required number of broadcasts of data gathering and 2) a general in-network computing strategy to achieve an upper bound within factor of the fundamental limits, where is the number of agents in the network. Next, focusing on two example networks, namely, arbitrary geometric networks and random Erdös-Rényi networks, we provide improved in-network computing schemes that are optimal in that they attain the fundamental limits, i.e., the lower and upper bounds are tight in scaling sense. Our main techniques are three distributed encoding techniques, called graph codes, which are designed, respectively, for the above-mentioned three scenarios. Our work, thus, extends and unifies previous works such as those of Gallager and Karamchandani on the number of broadcasts for distributed function computation in special network topologies, while bringing in novel techniques, e.g., from error-control coding and noisy circuits, for both upper and lower bounds. Autors: Yaoqing Yang;Soummya Kar;Pulkit Grover; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 6059 - 6084 Publisher: IEEE
» Graph Filters and the Z-Laplacian
 Abstract:In network science, the interplay between dynamical processes and the underlying topologies of complex systems has led to a diverse family of models with different interpretations. In graph signal processing, this is manifested in the form of different graph shifts and their induced algebraic systems. In this paper, we propose the unifying Z-Laplacian framework, whose instances can act as graph shift operators. As a generalization of the traditional graph Laplacian, the Z-Laplacian spans the space of all possible Z -matrices, i.e., real square matrices with nonpositive off-diagonal entries. We show that the Z -Laplacian can model general continuous-time dynamical processes, including information flows and epidemic spreading on a given graph. It is also closely related to general nonnegative graph filters in the discrete time domain. We showcase its flexibility by considering two applications. First, we consider a wireless communications networking problem modeled with a graph, where the framework can be applied to model the effects of the underlying communications protocol and traffic. Second, we examine a structural brain network from the perspective of low- to high-frequency connectivity. Autors: Xiaoran Yan;Brian M. Sadler;Robert J. Drost;Paul L. Yu;Kristina Lerman; Appeared in: IEEE Journal of Selected Topics in Signal Processing Publication date: Sep 2017, volume: 11, issue:6, pages: 774 - 784 Publisher: IEEE

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