###### Accueil » Publications dans le domaines des technologies » 10-2017
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 Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 10-2017 trié par par titre, page: 7
» Investigating Applications in Health Care [Book\Software Reviews]
 Résumé:This book explains the multiple directions in which RF/microwave technologies are heading toward healthcare and biosensing applications, the achievements that have been made so far, and the challenges for researchers to solve in the near future. It consists of seven chapters by 15 authors, many of whom are active on the IEEE Microwave Theory and Techniques Society (MTT-S) Technical Coordinating Committee MTT-10, Biological Effects and Medical Applications. Apart from the first two chapters (which are tutorials on microwave technology and the dielectric properties of tissue), the book consists of five chapters that review different applications of RF/microwave energy to health care and biosensing. This book provides essential theories and solutions for the transmitter and receiver hardware block. The solutions offered are very practical for a circuit system designer. Whether the particular applications of RF/microwaves discussed in this volume will ever pass muster and enter the realm of evidence-based medicine remains to be seen. In their focus on the nuts and bolts of engineering, the authors of this otherwise meritorious volume are telling only a small part of the story about developing medical technology. Auteurs: Kenneth R. Foster; Apparue dans: IEEE Microwave Magazine Date publication: 10.-2017, volume: 18, issue:6, pages: 126 - 127 Editeur: IEEE Document complet vers site de l'éditeur
» Investigation of a Fault-Tolerant Three-Level T-Type Inverter System
 Résumé:In recent years, a three-level T-type inverter has attracted considerable attention due to its advantages, such as simple structure and higher efficiency. However, the reliability of a three-level T-type inverter is particularly important as increased power switches are used. Therefore, a fault-tolerant three-level T-type inverter is proposed in this paper. Fault diagnosis and fault-tolerant control strategies for power switches both in half-bridge and neutral-point bridge are investigated. Under fault-tolerant operation, redundant fourth-leg is used to balance neutral-point voltage and the low-frequency voltage oscillation is eliminated completely. The fault ride-through capability and high-quality output waveforms can be obtained. The effectiveness of the proposed inverter topology and control methods is validated by the simulation and experimental results. Auteurs: Shuai Xu;Jianzhong Zhang;Jun Hang; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4613 - 4623 Editeur: IEEE Document complet vers site de l'éditeur
» Investigation of Border Trap Characteristics in the AlON/GeO2/Ge Gate Stacks
 Résumé:Aluminum oxynitride (AlON) is investigated as a germanium oxide (GeO) desorption barrier layer for Ge MOSFETs. Interface and border traps in the AlON/GeO2/Ge gate-stack are discussed in detail and compared with those in the Al2O3/GeO2/Ge gate-stack via MOS and MOSFET structures. Although the interface traps remain the same for AlON and Al2O3 in the gate stacks, the AlON gate-stack exhibits a reduced border trap, which results in improved reliability over the Al2O3 gate-stack. This is supported by both the charge-trapping and low-frequency noise analyses. Auteurs: Yujin Seo;Choong-Ki Kim;Tae-In Lee;Wan Sik Hwang;Hyun-Yong Yu;Yang-Kyu Choi;Byung Jin Cho; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 3998 - 4001 Editeur: IEEE Document complet vers site de l'éditeur
» Investigation of Double-Snapback Characteristic in Resistor-Triggered SCRs Stacking Structure
 Résumé:Achieving high latch-up immunity is critical for power-rail electrostatic discharge (ESD) clamp circuits in high-voltage (HV) integrated circuit products. To investigate how shunt resistance affects the transmission line pulsing current–voltage characteristics of resistance-triggered stacked silicon controlled rectifiers (SCRs), a lateral SCR (LSCR) and a modified LSCR were combined in several SCR stacked structures with various shunt resistances. Compared with in tradition stacked ESD cells, the snapback margin of the SCRs does not expand and can even be reduced. A high holding voltage of 33.4 V is achieved using the resistance-triggered stacked SCR technique in a $0.11~\mu \text{m}$ 32-V HV process. A trigger voltage of approximately 51 V and a failure current of 3.3 A is achieved in this experiment. According to theorem analysis based on a voltage decoupling equation, the minimum trigger voltage can probably be further reduced to 46 V by using the resistance-triggered stacked SCR technique. This paper can offer a simple guideline for designing ESD protection circuit using the resistor-triggered SCRs stacking structure. Auteurs: Shiang-Shiou Yen;Chun-Hu Cheng;Chia-Chi Fan;Yu-Chien Chiu;Hsiao-Hsuan Hsu;Yu-Pin Lan;Chun-Yen Chang; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4200 - 4205 Editeur: IEEE Document complet vers site de l'éditeur
» Investigation of Histology Region in Dielectric Measurements of Heterogeneous Tissues
 Résumé:The dielectric properties of tissues are the key parameters in electromagnetic medical technologies. Despite the apparent simplicity of the dielectric measurement process, reported data have been inconsistent for heterogeneous tissues. Dielectric properties may be attributed to heterogeneous tissues by identifying the tissue types that contributed to the measurement through histological analysis. However, accurate interpretation of the measurements with histological analysis requires first defining an appropriate histology region to examine. Here, we investigate multiple definitions for the probe sensing depth and uniquely calculate this parameter for measurements with a realistic range of tissues. We demonstrate that different sensing depth definitions are not equivalent, and may introduce error in dielectric data. Last, we propose an improved definition, given by the depth to which the probe can detect changes in the tissue sample, within the measurement uncertainty. We equate this sensing depth with histology depth, thus supporting the need of having the tissue region that contributes to the dielectric data be the same as that which is analyzed histologically. This paper demonstrates that, for these tissues, the histology depth is both frequency and tissue dependent. Therefore, the histology depth should be selected based on the measurement scenario; otherwise, inaccuracies in the data may result. Auteurs: Emily Porter;Martin O’Halloran; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5541 - 5552 Editeur: IEEE Document complet vers site de l'éditeur
» Investigation of Instabilities in a Folded-Waveguide Sheet-Beam TWT
 Résumé:Particle-in-cell (PIC) simulation was used for analyzing the instabilities due to zero-drive oscillations in a 220-GHz folded-waveguide (FW) traveling-wave tube. The equivalent circuit analysis based on the transmission line approach was used for the parametric design of the FW structures (FWSs) with circular and rectangular (horizontal and vertical) beam holes. Experimental validations with reference to the dispersion and interaction impedance characteristics were carried out on a scaled model of the slow wave structure in the Ku band. The oscillations observed in various configurations of the FWS were subsequently analyzed using the Brillouin diagram. The FWS with horizontal-rectangular beam hole was found to have a better immunity to instability compared to the other two configurations. Auteurs: H. S. Sudhamani;Jyothi Balakrishnan;S. U. M. Reddy; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4266 - 4271 Editeur: IEEE Document complet vers site de l'éditeur
» Investigation of Monolithic Radial Transmission Lines for Z-Pinch
 Résumé:A mathematical expression of the output voltage from a nonuniform transmission line with an arbitrary input pulse was deduced. The first arriving wave, peak power efficiency, and droop of the output voltage were further clarified using analytical method. The transmission characteristics of monolithic radial transmission lines (MRTLs) with different impedance profiles were investigated by 3-D electromagnetic (EM) simulation and it was found that the hyperbolic impedance profile is the best choice for future Z-pinch drivers. The results obtained from 3-D EM simulation are in good agreement with those obtained from the experiments on a scaled-down MRTL. Auteurs: Chongyang Mao;Xinxin Wang;Xiaobing Zou;Jane Lehr; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2639 - 2647 Editeur: IEEE Document complet vers site de l'éditeur
» Investigation of Robustness Capability of −730 V P-Channel Vertical SiC Power MOSFET for Complementary Inverter Applications
 Résumé:In this paper, a p-channel vertical 4H-silicon carbide (SiC) MOSFET (SiC p-MOSFET) has been fabricated successfully for the first time as a potential candidate for the complementary inverter application. The static characteristics and the robustness, including short circuit and avalanche capabilities of the p-MOSFET, are experimentally tested. Moreover, the comparison between the p-MOSFET and similar rating n-MOSFET is carried out. The short-circuit capability is 15% higher than that of the n-channel MOSFET. Furthermore, this paper also provides the physical insights into the failure mechanism during the short-circuit transient of the p- and n-MOSFET. Meanwhile, an electro-thermal analytical model is proposed to explain the thermal distribution during this transient. Last, the avalanche withstand time of the fabricated SiC p-MOSFET is experimentally demonstrated to be 27% higher than that of the n-channel one. It is concluded that the SiC p-MOSFET could be a competitive power switch applicable for high-frequency complementary inverters. Auteurs: Junjie An;Masaki Namai;Hiroshi Yano;Noriyuki Iwamuro; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4219 - 4225 Editeur: IEEE Document complet vers site de l'éditeur
» Investigation on the Conduction Mechanisms in Metal-Base Vertical Organic Transistors by DC and LF-Noise Measurements
 Résumé:Vertical organic transistors are a promising candidate to overcome the scaling limits of conventional horizontal organic field-effect devices. In this paper, based on the results of direct current (dc) and low-frequency noise (LFN) measurements, we propose a picture for the carrier transport in metal-base organic transistors in which transmission across the base is due to the combined action of both hot-carriers (HCs) and high-conduction paths (pores) in the metal base. Investigated devices employ pentacene and copper phthalocyanine as active layers for the emitter and collector regions, and a bilayer consisting of Au/MoO3 as injecting electrode. The dc analysis highlights that the charge transport in the investigated devices is due to drift diffusion of the emitter-injected carriers in the highest occupied molecular orbital (HOMO) band and is dominated by HC injection, although conduction via pores increases and becomes not negligible at high base–emitter fields. The LFN analysis highlights the presence of two dominant and uncorrelated 1/f current noise sources, one located between base and emitter, due to the fluctuations of the not-transmitted HC current, and a second source located between collector and emitter, due to the fluctuations of the transmitted HC current and/or to the fluctuations of the current through the pores in the metallic base. Auteurs: G. Giusi;E. Sarnelli;M. Barra;A. Cassinese;G. Scandurra;K. Nakayama;C. Ciofi; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4260 - 4265 Editeur: IEEE Document complet vers site de l'éditeur
» Investigations on Periodic Sequences With Maximum Nonlinear Complexity
 Résumé:The nonlinear complexity of a periodic sequence s is the length of the shortest feedback shift register that can generate s, and its value is upper bounded by the least period of s minus 1. In this paper, a recursive approach that generates all periodic sequences with maximum nonlinear complexity is presented, and the total number of such sequences is determined. The randomness properties of these sequences are also examined. Auteurs: Zhimin Sun;Xiangyong Zeng;Chunlei Li;Tor Helleseth; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6188 - 6198 Editeur: IEEE Document complet vers site de l'éditeur
» Ion Beam Monitoring Over a Biased Target
 Résumé:A specially designed beam profile monitor (BPM) was produced to be assembled over a biased target plate, with the aim of studying the effect of an ion beam deceleration system on the beam fluence due to beam dispersion. The new BPM was developed with a shape as flat as possible, so it could be attached to a biased target plate without affecting the target geometry, using a slit scan method to produce an high-resolution beam profile. This system was designed and installed on the high current ion implanter at the Laboratório de Aceleradores e Tecnologias de Radiação, at the Campus Tecnológico e Nuclear, of Instituto Superior Técnico, in Lisbon. The system is capable of showing the ion beam profile for low-energy ion beams below 15 keV, using a beam deceleration system. Auteurs: J. Lopes;J. Rocha;N. Catarino;M. Peres; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2767 - 2772 Editeur: IEEE Document complet vers site de l'éditeur
» IoT-Based Techniques for Online M2M-Interactive Itemized Data Registration and Offline Information Traceability in a Digital Manufacturing System
 Résumé:The integration of internet-of-things (IoT) technologies in the industry benefits digital manufacturing applications by allowing ubiquitous interaction and collaborative automation between machines. Online data collection and data interaction are critical for real-time decision making and machine collaborations. However, due to the specificity of digital manufacturing applications, the technical gap between IoT techniques and practical machine operation could hinder the efficient data interactions, collaborations between machines, and the effectiveness as well as the accuracy of itemized data collection. This investigation, therefore, identifies some major technical problems and challenges that current IoT-based digital manufacturing is facing, and proposes a method to bridge the technical gap for itemized product management. The highlights of this investigation are: 1) a data-oriented system architecture toward flexible data interaction between machines, 2) a customized machine-to-machine protocol for machine discovery, presence, and messaging, (3) flexible data structure and data presentation for interoperability, and (4) versatile information tracing approaches for product management. The proposed solutions have been implemented in PicknPack digital food manufacturing line, and achieved ubiquitous data interaction, online data collection, and versatile product information tracing methods have shown the feasibility and significance of the presented methods. Auteurs: Zhipeng Wu;Zhaozong Meng;John Gray; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2397 - 2405 Editeur: IEEE Document complet vers site de l'éditeur
» IPED2: Inheritance Path Based Pedigree Reconstruction Algorithm for Complicated Pedigrees
 Résumé:Reconstruction of family trees, or pedigree reconstruction, for a group of individuals is a fundamental problem in genetics. The problem is known to be NP-hard even for datasets known to only contain siblings. Some recent methods have been developed to accurately and efficiently reconstruct pedigrees. These methods, however, still consider relatively simple pedigrees, for example, they are not able to handle half-sibling situations where a pair of individuals only share one parent. In this work, we propose an efficient method, IPED2, based on our previous work, which specifically targets reconstruction of complicated pedigrees that include half-siblings. We note that the presence of half-siblings makes the reconstruction problem significantly more challenging which is why previous methods exclude the possibility of half-siblings. We proposed a novel model as well as an efficient graph algorithm and experiments show that our algorithm achieves relatively accurate reconstruction. To our knowledge, this is the first method that is able to handle pedigree reconstruction from genotype data when half-sibling exists in any generation of the pedigree. Auteurs: Dan He;Zhanyong Wang;Laxmi Parida;Eleazar Eskin; Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics Date publication: 10.-2017, volume: 14, issue:5, pages: 1094 - 1103 Editeur: IEEE Document complet vers site de l'éditeur
» IsAProteinDB: An Indexed Database of Trypsinized Proteins for Fast Peptide Mass Fingerprinting
 Résumé:In peptite mass fingerprinting, an unknown protein is fragmented into smaller peptides whose masses are accurately measured; the obtained list of weights is then compared with a reference database to obtain a set of matching proteins. The exponential growth of known proteins discourage the use of brute force methods, where the weights’ list is compared with each protein in the reference collection; luckily, the scientific literature in the database field highlights that well designed searching algorithms, coupled with a proper data organization, allow to quickly solve the identification problem even on standard desktop computers. In this paper, IsAProteinsDB, an indexed database of trypsinized proteins, is presented. The corresponding search algorithm shows a time complexity that does not significantly depends on the size of the reference protein database. Auteurs: Antonio d’Acierno; Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics Date publication: 10.-2017, volume: 14, issue:5, pages: 1195 - 1201 Editeur: IEEE Document complet vers site de l'éditeur
» Isotherm Tracking by an Autonomous Underwater Vehicle in Drift Mode
 Résumé:Studies of marine physical, chemical, and microbiological processes benefit from observing in a Lagrangian frame of reference. Some of these processes are related to specific density or temperature ranges. We have developed a method for a Tethys-class long-range autonomous underwater vehicle (LRAUV) (which has a propeller and a buoyancy engine) to track a targeted isothermal layer (within a narrow temperature range) in a stratified water column when operating in buoyancy-controlled drift mode. In this mode, the vehicle shuts off its propeller and autonomously detects the isotherm and stays with it by actively controlling the vehicle's buoyancy. The LRAUV starts on an initial descent to search for the target temperature. Once the temperature falls in the target center bracket, the vehicle records the corresponding depth and adjusts buoyancy to hold that depth. As long as the temperature stays within a tolerance range, the vehicle continues to hold that depth. If the temperature falls out of the tolerance range, the vehicle will increase or decrease buoyancy to reacquire the target temperature and track it. In a June 2015 experiment in Monterey Bay, CA, USA, an LRAUV ran the presented algorithm to successfully track a target isotherm for 13 h. Over the isotherm tracking duration, the LRAUV mostly remained in the 0.5 $^\circ$ C (peak-to-peak) tolerance range as designed, even though the water column's stratification kept changing. This work paves the way to coupling an LRAUV's complimentary modes of flight and drift—searching for an oceanographic feature in flight mode, and then switching to drift mode to track the feature in a Lagrangian frame of reference. Auteurs: Yanwu Zhang;Brian Kieft;M. Jordan Stanway;Robert S. McEwen;Brett W. Hobson;James G. Bellingham;John P. Ryan;Thomas C. O'Reilly;Ben Y. Raanan;Monique Messié;Jason M. Smith;Francisco P. Chavez; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 808 - 817 Editeur: IEEE Document complet vers site de l'éditeur
» ISS as a Platform for Optical Remote Sensing of Ecosystem Carbon Fluxes: A Case Study Using HICO
 Résumé:Data from the hyperspectral imager for coastal ocean (HICO), mounted on the International Space Station (ISS), were used to develop and test algorithms for remotely retrieving ecosystem productivity. Twenty-six HICO images were used from four study sites representing different vegetation types: grasslands, shrubland, and forest. Gross ecosystem production (GEP) data from eddy covariance were matched with HICO-derived spectra. Multiple algorithms were successful relating spectral reflectance with GEP, including: spectral vegetation indices (SVI), SVI in a light-use efficiency model framework, spectral shape characteristics through spectral derivatives and absorption feature analysis, and statistical models leading to multiband hyperspectral indices from stepwise regressions and partial least squares regression. Successful algorithms were able to achieve r2 better than 0.7 for both GEP at the overpass time and daily GEP. These algorithms were successful using a diverse set of observations combining data from multiple years, multiple times during growing season, different times of day, with different view angles, and different vegetation types. The demonstrated robustness of the algorithms presented in this study over these conditions provides some confidence in mapping spatial patterns of GEP, describing variability within fields, as well as the regional patterns. The ISS orbit provides periods with multiple observations collected at different times of the day within a period of a few days. Diurnal GEP patterns were estimated comparing the half-hourly average GEP from the flux tower against HICO estimates of GEP (r2 = 0.87) if morning, midday, and afternoon observations were available. Auteurs: Karl Fred Huemmrich;Petya K. Entcheva Campbell;Bo-Cai Gao;Larry B. Flanagan;Michael Goulden; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4360 - 4375 Editeur: IEEE Document complet vers site de l'éditeur
» Iterative Residual Generator for Fault Detection With Linear Time-Invariant State–Space Models
 Résumé:In this paper, an iterative residual generator (IRG) is proposed for discrete time-invariant state–space model with the aim of detecting faulty signals. By minimizing the mean square errors subject to unbiasedness constraint, a new filter with finite impulse response structure is derived. The resulting IRG is then obtained by extracting residual signal from the batch filter through several predictor/corrector iterations. It shows that IRG can provide a zero-mean Gaussian process regardless of previous estimation errors. More importantly, it includes the residual generation process in the Kalman filter as its special case. With the chi-square test, a numerical example is simulated to demonstrate that IRG can reduce the false alarm significantly compared with the traditional recursive strategy in the presence of actuator or sensor faults, and the estimation horizon length in IRG serves as a tuning parameter providing a tradeoff between the missed alarm and false alarm. Auteurs: Shunyi Zhao;Biao Huang; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5422 - 5428 Editeur: IEEE Document complet vers site de l'éditeur
» JANUS-Based Services for Operationally Relevant Underwater Applications
 Résumé:This paper presents the design, test, and experimentation at sea of four JANUS-based services for operationally relevant underwater applications: 1) first contact and language switching; 2) transmission of automatic identification system data to submerged assets; 3) transmission of meteorological and oceanographic data to underwater vessels; and 4) support in distressed submarine operations. On March 24, 2017, JANUS was promulgated as a NATO standard (STANAG 4748) [1], marking the first time that a digital acoustic communications protocol is adopted at international level. JANUS is an open, simple, and robust modulation and coding scheme developed by the NATO STO Centre for Maritime Research and Experimentation, in collaboration with academia and industry. The implementation of the services presented in this paper is based on a standardized protocol and offers the potential to widely increase the safety and efficiency in maritime operations. The objective of this paper is to demonstrate that JANUS can be used in support of maritime operations, potentially increasing their efficiency. Such demonstration is achieved through experimentation at sea of four operationally relevant JANUS-based services. The four JANUS-based services discussed were validated during two different sea trials: REP15-Atlantic and REP16-Atlantic. During those trials, various heterogeneous configurations were considered, including the use of a state-of-the-art diesel-electric submarine, guaranteeing maximum relevance for validation and evaluation of the designed solutions. The collected results demonstrate that JANUS is a viable solution for operationally relevant underwater applications, thus validating the objective of this paper. Additionally, encouraging feedback has been provided by the operational community participating to the trials. The capabilities demonstrated served- as an initial proof of concept and will certainly lead to newer requirements and eventually even more functionalities. Auteurs: Roberto Petroccia;João Alves;Giovanni Zappa; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 994 - 1006 Editeur: IEEE Document complet vers site de l'éditeur
» Job Scheduling at Cascading Machines
 Résumé:We consider the serial batching scheduling problem in which a group of machines can process multiple jobs continuously to reduce the processing times of the second and subsequent jobs. The maximum batch size is finite. Since all jobs in the same batch are loaded and unloaded simultaneously, a completed job has to wait for the others. We examine how to schedule all jobs to minimize the total completion time. If the batch size is only one, i.e., a single job per batch, the total processing time will be longer, since no reduction in processing time is possible. As a consequence, the total completion time will also be longer. On the other hand, if the batch size is large, the total completion time can be large. Each job has to wait until all jobs in the same batch are completed. We identify several optimality properties of the optimal batching sequence. These properties are used to develop a dynamic programming algorithm to optimize the batching sequences efficiently. The complexity of the proposed method depends only on the maximum batch size and the number of jobs. The improvement achieved with the proposed method when compared with two other batching rules is illustrated using two practical applications.Note to Practitioners— Machines with job cascading (or cluster tools) are commonly seen in semiconductor manufacturing processes. While meeting production move targets is a common goal for the nondelayed jobs, catching up with the schedule is an important task for the delayed jobs to achieve higher customer service level. From the viewpoint of scheduling, reducing the delay is equivalent to reducing completion time. Hence, we propose scheduling algorithms to reduce the completion time by taking advantage of the special structure of a cascading machine. In contrast to existing scheduling theory, the proposed algorithm can be efficient due to the small maximum batch size of real cascading machines. In addition to the theoretic- l contributions, this paper aims at solving practical problems through a rigorous approach. The finding and insight from this paper can be used to enhance shop floor control in a semiconductor fab. Auteurs: Edward Huang;Kan Wu; Apparue dans: IEEE Transactions on Automation Science and Engineering Date publication: 10.-2017, volume: 14, issue:4, pages: 1634 - 1642 Editeur: IEEE Document complet vers site de l'éditeur
» Joint 3D Beamforming and Resource Allocation for Small Cell Wireless Backhaul in HetNets
 Résumé:Network densification and 3D beamforming are two potential techniques to support the increasing data rate in the upcoming 5G cellular networks. This letter focuses on the joint optimization of 3D beamforming and resource allocation for the small cell (SC) backhaul in a heterogeneous network. After analyzing the achievable data rates of users and SCs based on Gamma distribution, we formulate a joint optimization problem to maximize the network throughput. We then convert it to an equivalent optimization problem and develop a low-complexity algorithm on joint 3D beamforming and resource allocation. Simulation results demonstrate the performance improvement of the proposed algorithm. Auteurs: Jinping Niu;Geoffrey Y. Li;Yanyan Li;Dingyi Fang;Xun Li; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2286 - 2289 Editeur: IEEE Document complet vers site de l'éditeur
 Résumé:Wireless energy transfer (WET) has received considerable attention for green communications. Unbalanced energy distribution and performance outages bring difficulties to the application of WET. This paper considers a network consisting of a WET-enabled access point (AP) and several energy-harvesting and source-powered user equipments (UEs). We investigate time-frequency resource allocation of downlink (DL) and uplink (UL) wireless information transfer (WIT) and DL WET. To improve energy efficiency and resource utilization, WET and WIT are orthogonally assigned at a low-frequency narrowband and a high-frequency wideband, respectively. A practical energy harvesting model is adopted, where power conversion efficiency depends on the received power instead of being a constant. To meet UEs’ different energy demands with the highest conversion efficiency, we develop beam switching, where the AP employs beamforming to charge UEs by jointly controlling power and time based on energy distributions and channel conditions. We formulate the overall energy minimization as a non-convex stochastic optimization problem, which is decomposed by fixing DL–UL time allocation ratio, transformed through Markov decision processes, and finally solved via linear programming. Simulation results verify the effectiveness of our proposed scheme on energy conservation and reveal the tradeoff of time allocation between DL and UL. Auteurs: Qizhong Yao;Tony Q. S. Quek;Aiping Huang;Hangguan Shan; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6751 - 6765 Editeur: IEEE Document complet vers site de l'éditeur
» Joint EH Time Allocation and Distributed Beamforming in Interference-Limited Two-Way Networks With EH-Based Relays
 Résumé:In this paper, we consider an amplify-and-forward-based two-way relaying network, in which the relays need to harvest energy from the received radio frequency signals to remain active in the network and assist data exchange between two transceivers. In particular, considering time-switching architecture, we investigate the problem of joint energy harvesting (EH) time allocation and distributed beamforming in the presence of interference. Specifically, assuming that the perfect knowledge of the interfering links is not available, we study three different design approaches. First, we maximize the sum-rate of the network subject to individual EH power constraints at relays. Resorting to the semi-definite relaxation (SDR) and successive upper-bound minimization techniques, we devise an iterative algorithm that efficiently solves such a challenging problem. Next, we minimize the total power consumed by the relays subject to the rate constraints at the transceivers. Finally, we minimize the EH-phase duration subject to the individual EH power constraints at the relays as well as the rate constraints at the transceivers. The rate constraints, however, make both second and third design optimization problems non-convex and complicated. Although no closed-form solutions are available for these approaches, we propose efficient schemes by applying the SDR technique followed by semi-definite programming problems. Auteurs: Soheil Salari;Il-Min Kim;Dong In Kim;Francois Chan; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6395 - 6408 Editeur: IEEE Document complet vers site de l'éditeur
» Joint Hybrid Tx–Rx Design for Wireless Backhaul With Delay-Outage Constraint in Massive MIMO Systems
 Résumé:This paper studies joint design of mixed-timescale hybrid precoding and combining to maximize the effective capacity for wireless backhaul in massive multiple-input multiple-output (MIMO) systems. Specifically, radio frequency (RF) analog processing is adaptive to statistical channel state information (CSI) while digital baseband processing is updated with instantaneous effective CSI. Equipped with traditional MIMO solutions at the baseband, the issue of RF design for both unconstrained-modulus and constant-modulus elements is addressed. Under the jointly correlated channel model, the objective function does not have a closed-form expression. In the unconstrained case, we derive the optimal RF solution structures, which lead to a combinatorial eigenmode selection formulation. Such an NP-hard problem is solved to near-optimality by semi-definite relaxation. In view of the additional difficulty posed by the non-convex modulus constraint, we exploit the problem structure to construct the constant-modulus design from the unconstrained-modulus solution which is cast as a problem of joint matrix approximation and solved by low-complexity Jacobi-like algorithms. Numerical results show that under loose and stringent delay-outage constraints, the mixed-timescale hybrid designs deliver effective rates comparable with other perfect CSI-based state-of-the-art baselines. Auteurs: Ruikai Mai;Tho Le-Ngoc;Duy H. N. Nguyen; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6736 - 6750 Editeur: IEEE Document complet vers site de l'éditeur
» Joint OSNR and Interchannel Nonlinearity Estimation Method Based on Fractional Fourier Transform
 Résumé:We propose a novel joint optical signal noise ratio (OSNR) and interchannel nonlinearity (NL) estimation method by fractional Fourier transformation of linear-frequency modulation (LFM) signal. In our method, LFM signal acts as time domain pilot in front of the payload. Our method of OSNR estimation is insensitive to nonlinear noise of optical fiber. Lower OSNR estimation error is also achieved in comparison with differential pilot method. The interchannel NL measurement procedures are also simplified compared with previous work. We also provide a scientific way to calculate the reference interchannel NL. The interchannel NL estimation error of our method is lower than 1 dB for 9 channels transmission after 10 spans with launch power from 10 to 14 dBm. Auteurs: Wanli Wang;Aiying Yang;Peng Guo;Yueming Lu;Yaojun Qiao; Apparue dans: Journal of Lightwave Technology Date publication: 10.-2017, volume: 35, issue:20, pages: 4497 - 4506 Editeur: IEEE Document complet vers site de l'éditeur
» Joint Power Allocation and Beamforming for Energy-Efficient Two-Way Multi-Relay Communications
 Résumé:This paper considers the joint design of user power allocation and relay beamforming in relaying communications, in which multiple pairs of single-antenna users exchange information with each other via multiple-antenna relays in two time slots. All users transmit their signals to the relays in the first time slot while the relays broadcast the beamformed signals to all users in the second time slot. The aim is to maximize the system’s energy efficiency (EE) subject to quality-of-service (QoS) constraints in terms of exchange throughput requirements. The QoS constraints are nonconvex with many nonlinear cross-terms, so finding a feasible point is already computationally challenging. The sum throughput appears in the numerator while the total consumption power appears in the denominator of the EE objective function. The former is a nonconcave function and the latter is a nonconvex function, making fractional programming useless for EE optimization. Nevertheless, efficient iterations of low complexity to obtain its optimized solutions are developed. The performance of the multiple-user and multiple-relay networks under various scenarios is evaluated to show the merit of the proposed method. Auteurs: Zhichao Sheng;Hoang Duong Tuan;Trung Q. Duong;H. Vincent Poor; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6660 - 6671 Editeur: IEEE Document complet vers site de l'éditeur
» Kalman-Gain Aided Particle PHD Filter for Multitarget Tracking
 Résumé:We propose an efficient sequential Monte Carlo probability hypothesis density (PHD) filter which employs the Kalman-gain approach during weight update to correct predicted particle states by minimizing the mean square error between the estimated measurement and the actual measurement received at a given time in order to arrive at a more accurate posterior. This technique identifies and selects those particles belonging to a particular target from a given PHD for state correction during weight computation. Besides the improved tracking accuracy, fewer particles are required in the proposed approach. Simulation results confirm the improved tracking performance when evaluated with different measures. Auteurs: Abdullahi Daniyan;Yu Gong;Sangarapillai Lambotharan;Pengming Feng;Jonathon Chambers; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2251 - 2265 Editeur: IEEE Document complet vers site de l'éditeur
» Kernel Recursive Least Squares With Multiple Feedback and Its Convergence Analysis
 Résumé:In kernel adaptive filters (KAFs), feedback network can lead to performance improvement from the aspects of estimation accuracy and convergence rate. In this brief, a novel feedback structure is developed and applied to the kernel recursive least squares (KRLS), generating the KRLS with multiple feedback (KRLS-MF). In the proposed KRLS-MF, multiple previous outputs are utilized to update the structure parameters in the recurrent form. The obtained parameters are also proved to be convergent. Compared with other KAFs with and without feedback, KRLS-MF can improve both the filtering accuracy and convergence rate, efficiently. Auteurs: Shiyuan Wang;Wanli Wang;Shukai Duan;Lidan Wang; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1237 - 1241 Editeur: IEEE Document complet vers site de l'éditeur
» KSF-OABE: Outsourced Attribute-Based Encryption with Keyword Search Function for Cloud Storage
 Résumé:Cloud computing becomes increasingly popular for data owners to outsource their data to public cloud servers while allowing intended data users to retrieve these data stored in cloud. This kind of computing model brings challenges to the security and privacy of data stored in cloud. Attribute-based encryption (ABE) technology has been used to design fine-grained access control system, which provides one good method to solve the security issues in cloud setting. However, the computation cost and ciphertext size in most ABE schemes grow with the complexity of the access policy. Outsourced ABE (OABE) with fine-grained access control system can largely reduce the computation cost for users who want to access encrypted data stored in cloud by outsourcing the heavy computation to cloud service provider (CSP). However, as the amount of encrypted files stored in cloud is becoming very huge, which will hinder efficient query processing. To deal with above problem, we present a new cryptographic primitive called attribute-based encryption scheme with outsourcing key-issuing and outsourcing decryption, which can implement keyword search function (KSF-OABE). The proposed KSF-OABE scheme is proved secure against chosen-plaintext attack (CPA). CSP performs partial decryption task delegated by data user without knowing anything about the plaintext. Moreover, the CSP can perform encrypted keyword search without knowing anything about the keywords embedded in trapdoor. Auteurs: Jiguo Li;Xiaonan Lin;Yichen Zhang;Jinguang Han; Apparue dans: IEEE Transactions on Services Computing Date publication: 10.-2017, volume: 10, issue:5, pages: 715 - 725 Editeur: IEEE Document complet vers site de l'éditeur
» Ku-/Ka-Band Extrapolation of the Altimeter Cross Section and Assessment With Jason2/AltiKa Data
 Résumé:A simple extrapolation technique is proposed for the intercalibration of the Ku- and Ka-band altimeter data based on a recent analytical scattering model referred to as “GO4.” This method is tested with AltiKa and Jason2-Ku altimeters using one year of reprocessed data with the improved retracking algorithm ICENEW. The variations of the normalized radar cross section with respect to the main oceanic parameters are investigated in the Ku and Ka bands; the latter band is shown to have an increased sensitivity to wind speed, significant wave height as well as sea surface temperature. As a by-product of this analysis, we derive an original expression for the swell impact on the mean square slope, which allows to correct the GO4 model for the contribution of long waves. We show that the Ku/Ka prediction agrees within 0.25 dB with the respective levels of AltiKa and Jason2-Ku cross sections at wind speed larger than 4 m/s. Auteurs: Charles-Antoine Guérin;Jean-Christophe Poisson;Fanny Piras;Laiba Amarouche;Jean-Claude Lalaurie; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5679 - 5686 Editeur: IEEE Document complet vers site de l'éditeur
» L-Band Quantum-dash Self-Injection Locked Multiwavelength Laser Source for Future WDM Access Networks
 Résumé:We propose and demonstrate a compact, cost-effective, multiwavelength laser source employing self-injection locking scheme on InAs/InP quantum-dash (Qdash) laser diode. The device is shown to exhibit Fabry–Perot modes or subcarriers selectivity of 1 to 16 between ∼1600–1610 nm, with corresponding mode power (side mode suppression ratio) variation of ∼10 (∼38) to ∼−2.5 (∼22) dBm (dB), and able to extend beyond 1610 nm, thereby encompassing >30 optical carriers. Then, we utilized a single self-locked optical carrier at 1609.6 nm to successfully transmit 128 Gb/s dual-polarization quadrature phase shift keying signal over 20 km single mode fiber with ∼−16 dBm receiver sensitivity. To stem the viability of unifying the transceivers and addressing the requirements of next generation access networks, we propose self-seeded Qdash laser based wavelength division multiplexed passive optical network, capable of reaching a data capacity of 2.0 Tb/s (${\rm{16\,\times \,128\, Gb/ s}}$ ) in L-band. Auteurs: Mohamed Adel Shemis;Amr Mohamed Ragheb;Muhammad Talal Ali Khan;Habib Ali Fathallah;Saleh Alshebeili;Khurram Karim Qureshi;Mohammed Zahed Mustafa Khan; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 7 Editeur: IEEE Document complet vers site de l'éditeur
» Laboratory Demonstration of a Multiterminal VSC-HVDC Power Grid
 Résumé:This paper presents the design, development, control, and supervision of a hardware-based laboratory multiterminal-direct-current (MTDC) testbed. This work is a part of the TWENTIES (transmission system operation with large penetration of wind and other renewable electricity sources in networks by means of innovative tools and integrated energy solutions) DEMO 3 European project, which aims to demonstrate the feasibility of a dc grid through experimental tests. This is a hardware-in-the-loop dc system testbed with simulated ac systems in real-time simulation; the dc cables and some converters are actual, at laboratory scale. The laboratory-scale testbed is homothetic to a full-scale high-voltage direct-current (HVDC) system: electrical elements are the same in per unit. The testbed is supervised by a supervisory control and data acquisition system based on PcVue. A primary control-based droop control method to provide dc grid power balance and coordinated control methods to dispatch power as scheduled by a transmission system operator are implemented. Since primary control acts as converter level by using local measurements, a coordinated control is proposed to manage the dc grid power flow. The implemented system is innovative and achievable for real-time real-world MTDC-HVDC grid applications. Auteurs: Sid-Ali Amamra;Frederic Colas;Xavier Guillaud;Pierre Rault;Samuel Nguefeu; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2339 - 2349 Editeur: IEEE Document complet vers site de l'éditeur
» Lake and Fjord Ice Imaging Using a Multifrequency Ground-Based Tomographic SAR System
 Résumé:The radar backscatter response of snow covered lake and fjord ice is investigated using a ground based multifrequency synthetic aperture radar system operated in a tomographic configuration. Direct imaging of the snow and ice layering is achieved by focusing the signal from a two-dimensional (2-D) synthetic array in the 3-D space. A mathematical derivation describing the propagation of electromagnetic waves across a dense and multilayered complex medium with arbitrary but finite number of layers is presented. It is used to estimate the depth and refractive indices of the snow and ice layers from the tomograms employing a simple least-square optimization scheme. The lake and fjord ice datasets are compared with respect to their vertical stratification and estimated refractive indices. The vertical structure of the reflectivity of the snow-covered lake ice is investigated and compared at two different frequencies, X-, and C-band. It is found that snow and ice volume responses at C-band are very low compared to the corresponding responses at X-band. At both frequencies, backscattering from surface and interface structures dominate volume contributions. Auteurs: Temesgen Gebrie Yitayew;Laurent Ferro-Famil;Torbjørn Eltoft;Stefano Tebaldini; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4457 - 4468 Editeur: IEEE Document complet vers site de l'éditeur
» Land Cover Classification via Multitemporal Spatial Data by Deep Recurrent Neural Networks
 Résumé:Nowadays, modern earth observation programs produce huge volumes of satellite images time series that can be useful to monitor geographical areas through time. How to efficiently analyze such a kind of information is still an open question in the remote sensing field. Recently, deep learning methods proved suitable to deal with remote sensing data mainly for scene classification(i.e., convolutional neural networks on single images) while only very few studies exist involving temporal deep learning approaches [i.e., recurrent neural networks (RNNs)] to deal with remote sensing time series. In this letter, we evaluate the ability of RNNs, in particular, the long short-term memory (LSTM) model, to perform land cover classification considering multitemporal spatial data derived from a time series of satellite images. We carried out experiments on two different data sets considering both pixel-based and object-based classifications. The obtained results show that RNNs are competitive compared with the state-of-the-art classifiers, and may outperform classical approaches in the presence of low represented and/or highly mixed classes. We also show that the alternative feature representation generated by LSTM can improve the performances of standard classifiers. Auteurs: Dino Ienco;Raffaele Gaetano;Claire Dupaquier;Pierre Maurel; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1685 - 1689 Editeur: IEEE Document complet vers site de l'éditeur
» Land Surface Temperature Estimate From Chinese Gaofen-5 Satellite Data Using Split-Window Algorithm
 Résumé:The Gaofen-5 (GF-5) satellite, the only satellite that provides the thermal infrared (TIR) sensor in the national high-resolution earth observation project of China, will observe earth surface at a spatial resolution of 40 m in four TIR channels. This paper aims at developing a new nonlinear, four-channel split-window (SW) algorithm to retrieve land surface temperature (LST) from GF-5 image. In the SW algorithm, its coefficients were obtained based on several subranges of atmospheric column water vapors (CWV) under various land surface conditions, in order to remove the atmospheric effect and improve the retrieval accuracy. Results showed that the new algorithm can obtain LST with root-mean-square errors of less than 1 K. Compared with previous two- and three-channel SW algorithms, the four-channel SW algorithm obtained better results in estimating LST, especially under moist atmospheres. Methods of estimating CWV and pixel emissivity were also conducted. The sensitive analysis of LST retrieval to instrument noise and uncertainty of pixel emissivity and water vapor demonstrated the good performance of the proposed algorithm. At last, the new SW algorithm was validated using ground-measured data at six sites, and some simulated images from airborne hyperspectral TIR data. Auteurs: Xin Ye;Huazhong Ren;Rongyuan Liu;Qiming Qin;Yao Liu;Jijia Dong; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5877 - 5888 Editeur: IEEE Document complet vers site de l'éditeur
» Large Alphabet Source Coding Using Independent Component Analysis
 Résumé:Large alphabet source coding is a basic and well-studied problem in data compression. It has many applications, such as compression of natural language text, speech, and images. The classic perception of most commonly used methods is that a source is best described over an alphabet, which is at least as large as the observed alphabet. In this paper, we challenge this approach and introduce a conceptual framework in which a large alphabet source is decomposed into “as statistically independent as possible” components. This decomposition allows us to apply entropy encoding to each component separately, while benefiting from their reduced alphabet size. We show that in many cases, such decomposition results in a sum of marginal entropies which is only slightly greater than the entropy of the source. Our suggested algorithm, based on a generalization of the binary independent component analysis, is applicable for a variety of large alphabet source coding setups. This includes the classical lossless compression, universal compression, and high-dimensional vector quantization. In each of these setups, our suggested approach outperforms most commonly used methods. Moreover, our proposed framework is significantly easier to implement in most of these cases. Auteurs: Amichai Painsky;Saharon Rosset;Meir Feder; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6514 - 6529 Editeur: IEEE Document complet vers site de l'éditeur
» Large Scale Document Categorization With Fuzzy Clustering
 Résumé:Clustering documents into coherent categories is a very useful and important step for document processing and understanding. The introducing of fuzzy set theory into clustering provides a favorable mechanism to capture overlapping among document clusters. Document dataset is commonly represented as a collection of high-dimensional vectors, which may not be able to fit into memory entirely, when the dataset is large and with a very high dimensionality. However, most of the existing fuzzy clustering approaches deal with small and static datasets. Some of them may have a good scalability but they are only effective for low dimensional data. The study presented in this paper is about new efforts on fuzzy clustering of large-scale and high-dimensional data—especially suitable for document categorization. To consider both large scale and high dimensionality into the problem formulation, our key idea is to incorporate document-tailored fuzzy clustering into a scheme, which is effective for dealing with a large-scale problem. We first identified three representative schemes in fuzzy clustering for handling large-scale data, namely sampling extension, single pass, and divide ensemble. The limitation of fuzzy C-means (FCM)-based approaches for a large document clustering are then investigated. Based on the study, we propose new approaches by incorporating each of hyperspherical FCM and fuzzy coclustering with the three scale-up schemes, respectively. This enables our new approaches to maintain effectiveness for high-dimensional data with an extended scalability. Extensive experimental studies with real-world large document datasets have been conducted and the results demonstrate that the proposed approaches perform consistently better over existing ones in document categorization. Auteurs: Jian-Ping Mei;Yangtao Wang;Lihui Chen;Chunyan Miao; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 10.-2017, volume: 25, issue:5, pages: 1239 - 1251 Editeur: IEEE Document complet vers site de l'éditeur
» Large Stroke High Fidelity PZN-PT Single-Crystal “Stake” Actuator
 Résumé:A new piezoelectric actuator design, called “Stake” actuator, is proposed and demonstrated in this work. As an example, the stake actuator is made of four d32–mode PZN-5.5%PT single crystals, each of 25mmL × 8mmW × 0.4mmT in dimensions, bonded with the aid of polycarbonate (PC) edge guide-cum-stiffeners into a square-pipe configuration for improved bending and twisting strengths and capped with top and bottom pedestals made of 1.5 mm thick anodized aluminium. The resultant stake actuator measured 9 mm × 9 mm × 28 mm. The hollow structure is a key design feature, which optimizes single crystal usage efficiency and lowers the overall cost of the actuator. The displacement-voltage responses, blocking forces, resonance characteristics of the fabricated stake actuator, as well as the load and temperature effects, are measured and discussed. Since d32 is negative for [011]-poled single crystal, the “Stake” actuator contracts in the axial direction when a positive polarity field is applied to the crystals. Biased drive is thus recommended when extensional displacement is desired. The single crystal stake actuator has negligible (<1%) hysteresis and a large linear strain range of > 0.13% when driven up to +300V (i.e., 0.75 kV/mm), which is close to the rhombohedral-to-orthorhombic transformation field (E RO) of 0.85 kV/mm of the single crystal used. The stake actuator displays a stroke of −36.5 μm (at +300V) despite its small overall dimensions, and has a blocking force of 114 N. The single crystal d 32 stake actuator fabricated displays more than 30% larger axial strain than the state-of-the-art PZT- stack actuators of comparable length as well as moderate blocking forces. Said actuators are thus ideal for applications when large displacements with simple open loop control are preferred. Auteurs: Yu Huang;Yuexue Xia;Dian Hua Lin;Kui Yao;Leong Chew Lim; Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Date publication: 10.-2017, volume: 64, issue:10, pages: 1617 - 1624 Editeur: IEEE Document complet vers site de l'éditeur
» LAXY: A Location-Based Aging-Resilient Xy-Yx Routing Algorithm for Network on Chip
 Résumé:Network on chip (NoC) is a scalable interconnection architecture for ever increasing communication demand between processing cores. However, in nanoscale technology size, NoC lifetime is limited due to aging processes of negative bias temperature instability, hot carrier injection, and electromigration. Usually, because of unbalanced utilization of NoC resources, some parts of the network experience more thermal stress and duty cycle in comparison with other parts, which may accelerate chip failure. To slow down the aging rate of NoC, this paper proposes an oblivious routing algorithm called location-based aging-resilient Xy-Yx (LAXY) to distribute packet flow over entire network. LAXY is based on the fact that dimension-ordered routing algorithms imposes the highest traffic load on the central nodes in mesh topologies. To balance the traffic over the network, certain routers at the east and the west of NoC, with dimension-order XY routing, statically are configured as YX. Various configurations have been explored for LAXY and the simulations show a specific configuration, called Fishtail, increases mean time to failure of the routers and interconnects by about 42% and 56%, respectively. Moreover, by balancing the load over the network, LAXY improves overall packet latency by about 7% in average, with negligible area overhead. Auteurs: Nezam Rohbani;Zahra Shirmohammadi;Maryam Zare;Seyed-Ghassem Miremadi; Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Date publication: 10.-2017, volume: 36, issue:10, pages: 1725 - 1738 Editeur: IEEE Document complet vers site de l'éditeur
» LCL Filter Design of a 50-kW 60-kHz SiC Inverter with Size and Thermal Considerations for Aerospace Applications
 Résumé:To achieve high power density, increasing the switching frequency of the power converter has become a trend. The LCL filter is a major contributor of the overall weight of a high-power-density converter (HPDC), especially the inverter-side inductor, which requires to suppress higher frequency harmonic contents at the inverter side. This paper describes a comprehensive design flow of the LCL filter for a 50-kW, 60-kHz two-level silicon carbide (SiC) inverter for high-power aerospace applications with space constraint and harsh ambient temperature environment. To meet the space constraint requirement and reduce the inductor size, specific design attention is made on a customized amorphous cored inductor with a comprehensive study on the relationships of inductor weight, core width, and total surface area with respect to air gap length. To overcome the harsh ambient temperature environment, a liquid cooling system of the amorphous cored inductor is also described. Auteurs: Yong Liu;Kye-Yak See;Shan Yin;Rejeki Simanjorang;Chin Foong Tong;Arie Nawawi;Jih-Sheng Jason Lai; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8321 - 8333 Editeur: IEEE Document complet vers site de l'éditeur
» Leakage Current and Low-Frequency Noise Analysis and Reduction in a Suspended SOI Lateral p-i-n Diode
 Résumé:In this paper, we present a detailed analysis of leakage current in a silicon-on-insulator (SOI) lateral P+P−N+ (p-i-n) diode suspended on a microheating platform, combining device experimental characterization and numerical simulation. The diode leakage currents have been extensively studied using the back-gate bias as a means to alter the space-charge (SC) condition at the P− region (I-region)/buried oxide interface from accumulation to full depletion, and finally to inversion. Both dark leakage current analysis and low-frequency noise characterization performed on the suspended SOI lateral p-i-n diode indicate device degradation induced by microelectromechanical systems postprocessing (i.e., deep reactive-ion etching or aluminum deposition). A low-temperature (~250 °C) in situ (i.e., using embedded microheater) annealing of SOI lateral p-i-n diode after postprocessing allows reduction of the diode leakage current and optimization of the device performance by neutralizing the interface traps and improving carriers’ lifetime and surface recombination velocity. Numerical simulations have been performed with Atlas/SILVACO for deeper analysis of the leakage current behavior in the lateral p-i-n diode and identification of the generation mechanism dominating the diode leakage behavior. Simulation reveals that the dominant generation rate in the diode depends on the SC conditions, the interface trap density, and the carriers’ lifetime in the I-region. The experimental and simulated behaviors of “as processed” and annealed diode leakage current are shown to be in good qualitative agreement. Auteurs: Guoli Li;Valeriya Kilchytska;Nicolas André;Laurent A. Francis;Yun Zeng;Denis Flandre; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4252 - 4259 Editeur: IEEE Document complet vers site de l'éditeur
» Learning from Near Misses [Electrical Safety]
 Résumé:Examines ways engineers can learn from near-miss accidents. Some near-miss incidents are not reported, perhaps because the culture of the company doesn’t encourage a worker to report a near miss. If we really want to learn from these situations, we could publicize a general definition of a near miss that would include incidents where a worker could have been injured or killed if the work proceeded, and we could encourage prompt reporting so corrections can be made quickly before someone else is hurt or killed. Auteurs: Daniel Doan; Apparue dans: IEEE Industry Applications Magazine Date publication: 10.-2017, volume: 23, issue:5, pages: 6 - 13 Editeur: IEEE Document complet vers site de l'éditeur
» Learning Parameter-Advising Sets for Multiple Sequence Alignment
 Résumé:While the multiple sequence alignment output by an aligner strongly depends on the parameter values used for the alignment scoring function (such as the choice of gap penalties and substitution scores), most users rely on the single default parameter setting provided by the aligner. A different parameter setting, however, might yield a much higher-quality alignment for the specific set of input sequences. The problem of picking a good choice of parameter values for specific input sequences is called parameter advising. A parameter advisor has two ingredients: (i) a set of parameter choices to select from, and (ii) an estimator that provides an estimate of the accuracy of the alignment computed by the aligner using a parameter choice. The parameter advisor picks the parameter choice from the set whose resulting alignment has highest estimated accuracy. In this paper, we consider for the first time the problem of learning the optimal set of parameter choices for a parameter advisor that uses a given accuracy estimator. The optimal set is one that maximizes the expected true accuracy of the resulting parameter advisor, averaged over a collection of training data. While we prove that learning an optimal set for an advisor is NP-complete, we show there is a natural approximation algorithm for this problem, and prove a tight bound on its approximation ratio. Experiments with an implementation of this approximation algorithm on biological benchmarks, using various accuracy estimators from the literature, show it finds sets for advisors that are surprisingly close to optimal. Furthermore, the resulting parameter advisors are significantly more accurate in practice than simply aligning with a single default parameter choice. Auteurs: Dan DeBlasio;John Kececioglu; Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics Date publication: 10.-2017, volume: 14, issue:5, pages: 1028 - 1041 Editeur: IEEE Document complet vers site de l'éditeur
» Learning to Recognize Human Activities Using Soft Labels
 Résumé:Human activity recognition system is of great importance in robot-care scenarios. Typically, training such a system requires activity labels to be both completely and accurately annotated. In this paper, we go beyond such restriction and propose a learning method that allow labels to be incomplete and uncertain. We introduce the idea of soft labels which allows annotators to assign multiple, and weighted labels to data segments. This is very useful in many situations, e.g., when the labels are uncertain, when part of the labels are missing, or when multiple annotators assign inconsistent labels. We formulate the activity recognition task as a sequential labeling problem. Latent variables are embedded in the model in order to exploit sub-level semantics for better estimation. We propose a max-margin framework which incorporate soft labels for learning the model parameters. The model is evaluated on two challenging datasets. To simulate the uncertainty in data annotation, we randomly change the labels for transition segments. The results show significant improvement over the state-of-the-art approach. Auteurs: Ninghang Hu;Gwenn Englebienne;Zhongyu Lou;Ben Kröse; Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence Date publication: 10.-2017, volume: 39, issue:10, pages: 1973 - 1984 Editeur: IEEE Document complet vers site de l'éditeur
» Less Becomes More for Microwave Imaging: Design and Validation of an Ultrawide-Band Measurement Array.
 Résumé:A compact, enclosed, ultrawide-band (UWB) antenna array is presented to acquire data for a quantitative microwave imaging method. Compared to existing systems, the proposed array allows a UWB antenna to be placed close to a target object while, at the same time, minimizing the volume of the imaging array. The antennas and metallic enclosure are designed to easily integrate with an iterative threedimensional (3-D) nonlinear inverse scattering technique. The volume of the internal imaging domain has been minimized for this particular architecture to reduce the computational time spent on reconstructing the dielectrics within the domain. Each cavity-backed element radiates toward the target and presents stable transmission characteristics across the 1-4-GHz band. Auteurs: David Gibbins;Dallan Byrne;Tommy Henriksson;Beatriz Monsalve;Ian J. Craddock; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 10.-2017, volume: 59, issue:5, pages: 72 - 85 Editeur: IEEE Document complet vers site de l'éditeur
» Level Set Segmentation Algorithm for High-Resolution Polarimetric SAR Images Based on a Heterogeneous Clutter Model
 Résumé:In this paper, a heterogeneous clutter model named ${\mathcal L}$ distribution is introduced into the level set method for segmentation of high-resolution polarimetric synthetic aperture radar (PolSAR) images. Level set methods are robust and effective techniques for segmentation. However, traditional level set methods for PolSAR data are based on the complex Wishart distribution, which is not an applicable model to high-resolution PolSAR images and heterogeneous regions such as forest and urban areas. The ${\mathcal L}$ distribution is proved to be a highly flexible model for multilook PolSAR data, which is based on the product model with a generalized-gamma-distributed texture component. The ${\mathcal L}$ -model-based level set segmentation method is assessed using C-band, X-band, and L-band PolSAR data acquired by RADARSAT-2, TerraSAR-X, and ESAR sensors, respectively. Experimental results show that the ${\mathcal L}$-distribution model has a better capacity for characterizing high-resolution PolSAR data, especially for extremely heterogeneous regions. Compared with the Wishart-model-based and Kummer-U-model-based level set methods and Markov random field based methods, it is observed that the proposed level set algorithm can obtain more precise segmentation results. Auteurs: Ruijin Jin;Junjun Yin;Wei Zhou;Jian Yang; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4565 - 4579 Editeur: IEEE Document complet vers site de l'éditeur
» Leveraging nMOS Negative Differential Resistance for Low Power, High Reliability Magnetic Memory
 Résumé:We propose, demonstrate, and assess a nontunneling-based nMOS voltage-controlled negative differential resistance (V-NDR) concept for overcoming the intrinsic efficiency and reliability shortcomings of magnetic random access memory memories (MRAM). Using nMOS V-NDR circuits in series with MRAM tunnel junctions, we experimentally observe 40 times reduction in current during switching, enabling write termination and read margin amplification. Large scale Monte Carlo simulations also show 5X improvement in write energy savings and demonstrate the robustness of the scheme against device variability. Auteurs: Shaodi Wang;Andrew Pan;Cecile Grezes;Pedram Khalili Amiri;Kang L. Wang;Chi On Chui;Puneet Gupta; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4084 - 4090 Editeur: IEEE Document complet vers site de l'éditeur
» Leveraging the Survivable All-Optical WDM Network Design With Network Coding Assignment
 Résumé:This letter investigates a novel use of network coding (NC) in 1 + 1 protection for transparent wavelength-division multiplexing networks by utilizing a cost-effective all-optical XOR encoder/decoder. In applying this scheme, we introduce a new problem, called routing, wavelength, and NC assignment, and formulate it as the integer linear programming model, aiming at maximizing the network throughput under constrained bandwidth capacity. We evaluate our proposal on the realistic topology, COST239, with all-to-one traffic setting. The numerical results on studied case show that the our NC-based approach could support up to 30% traffic more than the conventional 1 + 1 protection. Auteurs: Dao Thanh Hai; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2190 - 2193 Editeur: IEEE Document complet vers site de l'éditeur
» Line Detection as an Inverse Problem: Application to Lung Ultrasound Imaging
 Résumé:This paper presents a novel method for line restoration in speckle images. We address this as a sparse estimation problem using both convex and non-convex optimization techniques based on the Radon transform and sparsity regularization. This breaks into subproblems, which are solved using the alternating direction method of multipliers, thereby achieving line detection and deconvolution simultaneously. We include an additional deblurring step in the Radon domain via a total variation blind deconvolution to enhance line visualization and to improve line recognition. We evaluate our approach on a real clinical application: the identification of B-lines in lung ultrasound images. Thus, an automatic B-line identification method is proposed, using a simple local maxima technique in the Radon transform domain, associated with known clinical definitions of line artefacts. Using all initially detected lines as a starting point, our approach then differentiates between B-lines and other lines of no clinical significance, including Z-lines and A-lines. We evaluated our techniques using as ground truth lines identified visually by clinical experts. The proposed approach achieves the best B-line detection performance as measured by the F score when a non-convex $\ell _{\text {p}}$ regularization is employed for both line detection and deconvolution. The F scores as well as the receiver operating characteristic (ROC) curves show that the proposed approach outperforms the state-of-the-art methods with improvements in B-line detection performance of 54%, 40%, and 33% for ${\text {F}}_{0.5}$ , ${\text {F}}_{1}$ , and ${\text {F}}_{2}$ ,- respectively, and of 24% based on ROC curve evaluations. Auteurs: Nantheera Anantrasirichai;Wesley Hayes;Marco Allinovi;David Bull;Alin Achim; Apparue dans: IEEE Transactions on Medical Imaging Date publication: 10.-2017, volume: 36, issue:10, pages: 2045 - 2056 Editeur: IEEE Document complet vers site de l'éditeur
» Linearity Enhancement of a Fully Integrated 6-GHz GaN Power Amplifier
 Résumé:A large-signal nonlinearity compensation technique is developed to improve the linearity of RF GaN power amplifiers. The design of a high power amplifier employing both common-source (CS) and common-gate (CG) GaN high-electron mobility transistors is presented for the IEEE 802.11p standard. The power amplifier is fabricated in 0.25- $\mu \text{m}$ GaN-on-SiC technology and occupies 1.7 mm $\times1.2$ mm. The measurements show that 35-dBm output 1-dB compression point (OP1 dB) is obtained with 39-dBm OIP3 for two-tone intermodulation distortion testing. It also achieves 31% drain efficiency at 28.8-dBm output power with 10-V supply voltage considering a more than 6-dB back-off for orthogonal frequency division multiplexing-modulated signals. Linearity enhancement by means of the proposed CS–CG configuration is demonstrated in a fully integrated GaN power amplifier at 6 GHz. Auteurs: Pilsoon Choi;Ujwal Radhakrishna;Chirn Chye Boon;Li-Shiuan Peh;Dimitri Antoniadis; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 927 - 929 Editeur: IEEE Document complet vers site de l'éditeur
» Linearizing Discrete-Time Hybrid Systems
 Résumé:Model-based design approaches for embedded systems aim at generating correct-by-construction control software, guaranteeing that the closed-loop system (controller and plant) meets given system level formal specifications. This technical note addresses control synthesis for safety and reachability properties of possibly nonlinear discrete-time hybrid systems. By means of a syntactical transformations that requires nonlinear terms to be Lipschitz continuous functions, we overapproximate nonlinear dynamics with a linear system whose controllers are guaranteed to be controllers of the original system. We evaluate performance of our approach on meaningful control synthesis benchmarks, also comparing it to a state-of-the-art tool. Auteurs: Vadim Alimguzhin;Federico Mari;Igor Melatti;Ivano Salvo;Enrico Tronci; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5357 - 5364 Editeur: IEEE Document complet vers site de l'éditeur
» List of Reviewers for 2016/2017
 Résumé:The IEEE Transactions on Automation Science and Engineering (T-ASE) wishes to thank the 987 reviewers over the past year who have performed an essential role in maintaining the quality of this publication. T-ASE strives for the 90–90 standard, i.e., 90% of papers should be reviewed within 90 days of submission. The review process starts when the Editor-in-Chief assigns the paper to an Editor, who assigns it to an Associate Editor (AE). The AE then obtains confirmation from 3–5 reviewers, carefully studies the results, and makes a recommendation to the Editor, who then makes a decision that is reported back to the lead author. This review process is very demanding, especially under the time constraints. We have summarized the process under “Guidelines for T-ASE Editors and AEs for Handling Papers” on our website. I am pleased to report that submissions have steadily increased (over 1000 in 2016) and our Impact Factor is now 3.502, an 16.5% increase over last year. As we strive to increase the quality and impact of the journal, we rely on the hard work of our reviewers and members of the Editorial Board. To those dedicated volunteers, and to anyone who may have been inadvertently omitted from the list below, we extend our sincere appreciation. Auteurs: Michael Y. Wang; Apparue dans: IEEE Transactions on Automation Science and Engineering Date publication: 10.-2017, volume: 14, issue:4, pages: 1793 - 1797 Editeur: IEEE Document complet vers site de l'éditeur
» Load Modulation of Harmonically Tuned Amplifiers and Application to Outphasing Systems
 Résumé:Modulation of load impedance is an effective way to maintain efficient power amplifier (PA) operation over high dynamic range modulated signals. For high efficiency, a load modulation approach can be applied to inherently efficient classes of PAs such as those with harmonic tuning: Class J, Class F, and Inverse Class F. This paper presents an analysis of harmonically tuned (HT) amplifiers operating under load modulation conditions, deriving the optimal loading trajectories for these multiple classes of operation. Because these load trajectories are complex, it is then shown—through a series of analysis, simulations, and measurements—that HT amplifiers are better suited for outphasing systems, than conventional amplifiers such as Class B. A design methodology is proposed and validated through design and measurement of a 900-MHz outphasing system, comprising of two Gallium Nitride Class J branch PAs, delivering 44.6 dBm with 75% PAE at saturation, while mantaining PAE above 60% over a 7-dB output power back-off. Auteurs: Paolo Enrico de Falco;Prathamesh Pednekar;Konstantinos Mimis;Souheil Ben Smida;Gavin Watkins;Kevin Morris;Taylor Wallis Barton; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3596 - 3612 Editeur: IEEE Document complet vers site de l'éditeur
» Local Area Radiation Sidelobe Suppression of Reflector Antennas by Embedding Periodic Metallic Elements Along the Edge Boundary
 Résumé:This communication presents a simple and useful technique to suppress the radiation sidelobe levels (SLLs) of reflector antennas by embedding reflecting elements around the edge boundary. Due to the fact that sidelobes mainly arise from the edge diffractions, the reflecting elements can alter the phase distribution of induced currents along the edge boundary, and therefore reduce the sidelobes through the destructive cancellation of fields radiated from these elements. The desired phases are found through the implementation of pattern synthesis technique such as genetic algorithm to optimize the SLLs. This technique of edge current phase alternation may be employed, in conjunction with using a tapered feed radiation to illuminate the reflector, to control both amplitudes and phases of edge currents. Thus, the edge diffraction mechanism may be better controlled to optimize SLLs. In this communication, both resonant and nonresonant types of metallic elements are implemented and compared to illustrate their characteristics of radiations in SLL suppression. This technique is particularly useful to suppress the SLLs within a local angular region. Numerical results based on the method of moment analysis are presented to validate the feasibility. Auteurs: Hsi-Tseng Chou;Hsien-Kwei Ho; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5611 - 5616 Editeur: IEEE Document complet vers site de l'éditeur
» Local Submodularization for Binary Pairwise Energies
 Résumé:Many computer vision problems require optimization of binary non-submodular energies. We propose a general optimization framework based on local submodular approximations (LSA). Unlike standard LP relaxation methods that linearize the whole energy globally, our approach iteratively approximates the energy locally. On the other hand, unlike standard local optimization methods (e.g., gradient descent or projection techniques) we use non-linear submodular approximations and optimize them without leaving the domain of integer solutions. We discuss two specific LSA algorithms based on trust region and auxiliary function principles, LSA-TR and LSA-AUX. The proposed methods obtain state-of-the-art results on a wide range of applications such as binary deconvolution, curvature regularization, inpainting, segmentation with repulsion and two types of shape priors. Finally, we discuss a move-making extension to the LSA-TR approach. While our paper is focused on pairwise energies, our ideas extend to higher-order problems. The code is available online. Auteurs: Lena Gorelick;Yuri Boykov;Olga Veksler;Ismail Ben Ayed;Andrew Delong; Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence Date publication: 10.-2017, volume: 39, issue:10, pages: 1985 - 1999 Editeur: IEEE Document complet vers site de l'éditeur
» Localization Accuracy Improvement of a Visible Light Positioning System Based on the Linear Illumination of LED Sources
» Locally Optimal Inspired Detection in Snapping Shrimp Noise
 Résumé:In this paper, we address the problem of detecting a known signal in snapping shrimp noise. The latter dominates the ambient soundscape at medium-to-high frequencies in warm shallow waters. The noise process is impulsive, exhibits memory and is modeled effectively by stationary $\alpha$ -sub-Gaussian noise with memory order $m$ ($\alpha$SGN( $m$)), which is essentially an impulsive Markov process. Robust detectors have long been used to mitigate the impact of impulsive noise on the performance of digital systems. However, conventional notions of robustness do not assume memory within the noise process. The $\alpha$SGN($m$ ) model offers a mathematical model to develop robust detectors that also exploit the mutual information between noise samples. Recent works in this area highlight substantial improvement in detection performance over traditional robust methods in snapping shrimp noise. However, implementing such detectors is a challenge as they are parametric and computationally taxing. To achieve more realizable detectors, we derive the locally optimal detector for $\alpha$SGN( $m$). From it, we introduce the generalized memory-based sign correlator and its variants, all of which offer near-optimal performance in $\alpha$SGN($m$ ). The proposed detectors off- r excellent performance in snapping shrimp noise and low computational complexity. These properties make them attractive for use in underwater acoustical systems operating in snapping shrimp noise. Auteurs: Ahmed Mahmood;Mandar Chitre;Hari Vishnu; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 1049 - 1062 Editeur: IEEE Document complet vers site de l'éditeur
» Locally Orthogonal Training Design for Cloud-RANs Based on Graph Coloring
 Résumé:We consider training-based channel estimation for a cloud radio access network (CRAN), in which a large amount of remote radio heads and users are randomly scattered over the service area. In this model, assigning orthogonal training sequences to all users will incur a substantial overhead to the overall network, and is even impossible when the number of users is large. Therefore, in this paper, we introduce the notion of local orthogonality, under which the training sequence of a user is orthogonal to those of the other users in its neighborhood. We model the design of locally orthogonal training sequences as a graph coloring problem. Then, based on the theory of random geometric graph, we show that the minimum training length scales in the order of $\ln K$ , where $K$ is the number of users covered by a CRAN. This implies that the proposed training design yields a scalable solution to sustain the need of large-scale cooperation in CRANs. Auteurs: Jianwen Zhang;Xiaojun Yuan;Ying Jun Zhang; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6426 - 6437 Editeur: IEEE Document complet vers site de l'éditeur
» LocDyn: Robust Distributed Localization for Mobile Underwater Networks
 Résumé:How do we self-localize large teams of underwater nodes using only noisy range measurements? How do we do it in a distributed way, and incorporating dynamics into the problem? How do we reject outliers and produce trustworthy position estimates? And what if some of the vehicles can measure angular information? The stringent acoustic communication constraints and accuracy needs of our geophysical survey application demand fast and very accurate localization methods. We address dynamic localization as a MAP estimation problem where the prior encodes kinematic information, and we apply a convex relaxation method that takes advantage of previous estimates at each measurement acquisition step. The resulting LocDyn algorithm is fast: It converges at an optimal rate for first order methods. LocDyn is distributed: There is no fusion center responsible for processing acquired data and the same simple computations are performed at each node. LocDyn is accurate: Numerical experiments attest to about 30% smaller positioning error than a comparable Kalman filter. LocDyn is robust: It rejects outlier noise, while benchmarking methods succumb in terms of positioning error. Auteurs: Cláudia Soares;João Gomes;Beatriz Quintino Ferreira;João Paulo Costeira; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 1063 - 1074 Editeur: IEEE Document complet vers site de l'éditeur
» Long Period Fiber Grating Inscribed in Hollow-Core Photonic Bandgap Fiber for Gas Pressure Sensing
 Résumé:In this paper, we have proposed and experimentally prepared an improved gas pressure sensing device. It is mainly constructed by a short hollow silica tube segment and a CO2-laser-induced long period grating in hollow-core photonic bandgap fiber (HC-PBF). To effectively enhance the interaction between light in the air-core of HC-PBF and external surroundings, thus to achieve the best possible gas pressure sensitivity, a microchannel is introduced in the middle of the hollow silica tube segment with the femtosecond laser processing technique. The corresponding gas pressure experiments demonstrate that the resonant wavelength of the LPFG shows a blue shift up to −1.3 nm/MPa. Moreover, the temperature response sensitivity of this sensor is as low as 5.3 pm/°C and enable it possible as a temperature-insensitive gas pressure measure apparatus. Auteurs: Jian Tang;Zhe Zhang;Guolu Yin;Shen Liu;Zhiyong Bai;Zhengyong Li;Mi Deng;Ying Wang;Changrui Liao;Jun He;Wei Jin;Gang-Ding Peng;Yiping Wang; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 7 Editeur: IEEE Document complet vers site de l'éditeur
» Long-Range OFDR-Based Distributed Vibration Optical Fiber Sensor by Multicharacteristics of Rayleigh Scattering
 Résumé:We present a long-range optical frequency domain reflectometry (OFDR) based distributed vibration optical fiber sensor (DVOFS) by multicharacteristics of Rayleigh scattering. Comparing with utilizing a single characteristic of Rayleigh scattering, by using multicharacteristics of Rayleigh scattering, two or more simultaneous vibration events in a long sensing range can be detected and located in DVOFS. In a single-ended OFDR-based DVOFS without any optical amplification, we can discriminate two simultaneous vibration events by two different characteristics. One is the local Rayleigh scattering spectra shifts for locating the first vibration event. The other is the “V” shape in Rayleigh scattering signals in the spatial domain for locating the second vibration event. The sensing range of this DVOFS is 92 km and the spatial resolution of locating vibration events is 13 m. Auteurs: Zhenyang Ding;Di Yang;Kun Liu;Junfeng Jiang;Yang Du;Bingkun Li;Minghao Shang;Tiegen Liu; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 10 Editeur: IEEE Document complet vers site de l'éditeur
» Loss Function Modeling of Efficiency Maps of Electrical Machines
 Résumé:This paper presents a novel approach in the modeling of efficiency maps for electrical machines. It is based on using the sum of terms in the form of kmnTmωn to represent the variation of the stator and rotor copper, iron, and magnet losses with torque and speed. The effect of each term on the shape of the efficiency map is explored. Analysis is performed on the calculated efficiency and loss maps of an induction, an interior permanent magnet, and a surface permanent magnet machine to demonstrate the validity of the approach. Auteurs: Amin Mahmoudi;Wen L. Soong;Gianmario Pellegrino;Eric Armando; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4221 - 4231 Editeur: IEEE Document complet vers site de l'éditeur
» Loss Identification in a Double Rotor Electrical Variable Transmission
 Résumé:An electrical variable transmission (EVT) is an electromagnetic power-split device with two mechanical and two electrical ports. It can be used in hybrid electric vehicles to split the power to the wheels in a part coming from the combustion engine and a part exchanged with the battery. Although crucial for the EVT design and evaluation, no papers are found to give a detailed overview of the different loss components in such a machine and how they can be calculated and measured. In contrast to conventional electrical machines, this machine has more degrees of freedom, which can be exploited to measure the different loss contributions separately. This paper proposes a methodology to identify and measure the different loss components in this kind of machines. The proposed method is able to identify the iron losses in stator and inner rotor, the copper losses, bearing losses, and slip ring friction losses separately. To this end, measurements of both torque and speed sensors in different operating points are combined. The methods are applied to identify the different loss contributions in a prototype permanent magnet assisted EVT, both in no-load operation as under load where its functionality as power-split device is evaluated. Auteurs: Joachim Druant;Hendrik Vansompel;Frederik De Belie;Peter Sergeant; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7731 - 7740 Editeur: IEEE Document complet vers site de l'éditeur
» Loss of low-frequency data in on- line frequency response analysis of transformers
 Résumé:Power transformers are a key component of the electricity supply grid. Monitoring and assessment of their condition has always been of great concern [1]. In critical situations, transformer failures can cause irreversible damage and considerable financial loss to the grid stakeholders or even the end-users [2], [3]. In this regard, mechanical defects are considered a major problem in distribution and power transformers [4]. Consequently various diagnostic techniques have been developed to identify transformer mechanical defects and winding deformation. Auteurs: Mehdi Bagheri;Svyatoslav Nezhivenko;B. T. Phung; Apparue dans: IEEE Electrical Insulation Magazine Date publication: 10.-2017, volume: 33, issue:5, pages: 32 - 39 Editeur: IEEE Document complet vers site de l'éditeur
» Lossless Compression Decoders for Bitstreams and Software Binaries Based on High-Level Synthesis
 Résumé:As the density of field-programmable gate arrays continues to increase, the size of configuration bitstreams grows accordingly. Compression techniques can reduce memory size and save external memory bandwidth. To accelerate the configuration process and reduce the software startup time, four open-source lossless compression decoders developed using high-level synthesis techniques are presented. Moreover, in order to balance the objectives of compression ratio, decompression throughput, and hardware resource overhead, various improvements and optimizations are proposed. Full bitstreams and software binaries have been collected as a benchmark, and 33 partial bitstreams have also been developed and integrated into the benchmark. Evaluations of the synthesizable compression decoders are demonstrated on a Xilinx ZC706 board, showing higher decompression throughput than those of the existing lossless compression decoders using our benchmark. The proposed decoders can reduce software startup time by up to 31.23% in embedded systems and 69.83% reduction of reconfiguration time for partial reconfigurable systems. Auteurs: Jian Yan;Junqi Yuan;Philip H. W. Leong;Wayne Luk;Lingli Wang; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2842 - 2855 Editeur: IEEE Document complet vers site de l'éditeur
» Lossless In-Network Processing and Its Routing Design in Wireless Sensor Networks
 Résumé:In many domain-specific monitoring applications of wireless sensor networks (WSNs), such as structural health monitoring, volcano tomography, and machine diagnosis, the raw data in WSNs are required to be losslessly gathered to the sink, where a specialized centralized algorithm is then executed to extract some global features or model parameters. To reduce the large raw data transmission, in-network processing is usually employed. However, different from most existing in-network processing works that pre-assume some common computation/aggregation functions, in-network processing of a given centralized algorithm requires exact partitioning of the algorithm first and then appropriately assigning the partitioned computations into WSNs. We call this lossless in-network processing, which has not been studied much. Lossless in-network processing raises two questions: 1) what pattern should a centralized algorithm be partitioned into so that the partitioned computations can be flexibly assigned into a WSN with arbitrary topology? and 2) for each partition pattern, how should efficient routing for the resource-limited sensor nodes be designed? These two questions can be referred to as a topology-constrained computation partition problem and a computation-constrained routing design problem, respectively. In this paper, we first introduce some general patterns on the topology-constrained computation partition. Then, with the computation constraints in the patterns, we present a series of novel routing schemes customized for different cases of computation results. The work in this paper can also serve as a guideline for distributed computing of big data, where the data spreads in a large network. Auteurs: Peng Guo;Xuefeng Liu;Jiannong Cao;Shaojie Tang; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6528 - 6542 Editeur: IEEE Document complet vers site de l'éditeur
» Lossless In-Network Processing in WSNs for Domain-Specific Monitoring Applications
 Résumé:Internet of things (IOT) is emerging as sensing paradigms in many domain-specific monitoring applications in smart cities, such as structural health monitoring (SHM) and smart grid monitoring. Due to the large size of the monitoring objects (e.g., civil structure or the power grid), plenty of sensors need to be deployed and organized to be a large scale of multihop wireless sensor networks (WSNs), which tends to have quite high transmission cost. In-network processing is an efficient way to reduce the transmission cost in WSNs. However, implementing in-network processing for above domain-specific monitoring usually requires to losslessly distribute a dedicate domain-specific algorithm into WSNs, which is much different from most existing in-network processing works. This paper conducts a case study of a classic centralized SHM algorithm, i.e., eigensystem realization algorithm (ERA), and shows how to losslessly and optimally in-network process ERA, especially the typical feature extraction method, i.e., that is singular value decomposition (SVD) therein, in a WSN. Based on whether the intermediate data can be processed together or not by sensor nodes, we respectively implement tree-based in-network processing of SVD and chain-based in-network processing of SVD in WSNs. We prove that using an appropriate shallow light tree as routes for tree-based in-network processing of SVD, can achieve the approximation ratio ${\text{1}}+\sqrt{2}$ (in terms of transmission cost), while for the chain-based in-network processing of SVD, we design two efficient heuristic algorithms for searching the optimal routes. Extensive simulation results validate the efficiency of these proposed schemes that are customized for SVD-based IOT applications. Auteurs: Peng Guo;Jiannong Cao;Xuefeng Liu; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2130 - 2139 Editeur: IEEE Document complet vers site de l'éditeur
» Lotfi A. Zadeh In Memoriam
 Résumé: Auteurs: Piero P. Bonissone;Enrique H. Ruspini; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 10.-2017, volume: 25, issue:5, pages: 1021 - 1022 Editeur: IEEE Document complet vers site de l'éditeur
» Low Correlation Sequences From Linear Combinations of Characters
 Résumé:Pairs of binary sequences formed using linear combinations of multiplicative characters of finite fields are exhibited that, when compared with a random sequence pairs, simultaneously achieve significantly lower mean square autocorrelation values (for each sequence in the pair) and significantly lower mean square crosscorrelation values. If we define crosscorrelation merit factor analogously to the usual merit factor for autocorrelation, and if we define demerit factor as the reciprocal of merit factor, then randomly selected binary sequence pairs are known to have an average crosscorrelation demerit factor of 1. Our constructions provide sequence pairs with a crosscorrelation demerit factor significantly less than 1, and at the same time, the autocorrelation demerit factors of the individual sequences can also be made significantly less than 1 (which also indicates better than average performance). The sequence pairs studied here provide combinations of autocorrelation and crosscorrelation performance that are not achievable using sequences formed from single characters, such as maximal linear recursive sequences (m-sequences) and Legendre sequences. In this paper, exact asymptotic formulae are proved for the autocorrelation and crosscorrelation merit factors of sequence pairs formed using linear combinations of multiplicative characters. Data is presented that shows that the asymptotic behavior is closely approximated by sequences of modest length. Auteurs: Kelly T. R. Boothby;Daniel J. Katz; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6158 - 6178 Editeur: IEEE Document complet vers site de l'éditeur
» Low-Complexity Digit-Level Systolic Gaussian Normal Basis Multiplier
 Résumé:Normal basis multiplication over $GF(2^{m})$ is widely used in various applications such as elliptic curve cryptography. As a special class of normal basis with low complexity, Gaussian normal basis (GNB) has received considerable attention recently. In this paper, we propose a novel decomposition algorithm to develop a digit-level (DL) low-complexity systolic structure for GNB multiplication over $GF(2^{m})$ . First, we propose two algorithms separately to achieve a systolic GNB multiplier with low critical path delay and low register complexity. Next, we present the corresponding structure according to the proposed algorithm (combination of previous two proposed algorithms). Compared with the existing systolic DL GNB multipliers (through both the theoretical and application-specific integrated circuit comparison), the proposed multiplier achieves significantly less area-delay product (ADP), e.g., for a systolic structure of digit size of 8 for $GF(2^{409})$ , the proposed structure has 12.3% less ADP compared to the best of the existing designs, for the same digit size. Auteurs: Qiliang Shao;Zhenji Hu;Shaobo Chen;Pingxiuqi Chen;Jiafeng Xie; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2817 - 2827 Editeur: IEEE Document complet vers site de l'éditeur
 Résumé:In practical wireless systems, the successful implementation of resource allocation techniques strongly depends on the algorithmic complexity. Consider a cloud-radio access network (CRAN), where the central cloud is responsible for scheduling devices to the frames’ radio resources blocks (RRBs) of the single-antenna base-stations (BSs), adjusting the transmit power levels, and for synchronizing the transmit frames across the connected BSs. Previous studies show that the jointly coordinated scheduling and power control problem in the considered CRAN can be solved using an approach that scales exponentially with the number of BSs, devices, and RRBs, which makes the practical implementation infeasible for reasonably sized networks. This letter instead proposes a low-complexity solution to the problem, under the constraints that each device cannot be served by more than one BS but can be served by multiple RRBs within each BS frame, and under the practical assumption that the channel is constant during the duration of each frame. The paper utilizes graph-theoretical based techniques and shows that constructing a single power control graph is sufficient to obtain the optimal solution with a complexity that is independent of the number of RRBs. Simulation results reveal the optimality of the proposed solution for slow-varying channels, and show that the solution performs near-optimal for highly correlated channels. Auteurs: Ahmed Douik;Hayssam Dahrouj;Tareq Y. Al-Naffouri;Mohamed-Slim Alouini; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2298 - 2301 Editeur: IEEE Document complet vers site de l'éditeur
» Low-Cost Adaptive Lebesgue Sampling Particle Filtering Approach for Real-Time Li-Ion Battery Diagnosis and Prognosis
 Résumé:In the past decades, fault diagnosis and prognosis (FDP) approaches were developed in the Riemann sampling (RS) framework, in which samples are taken and algorithms are executed in periodic time intervals. With the increase of system complexity, a bottleneck of real-time implementation of RS-based FDP is limited calculation resources, especially for distributed applications. To overcome this problem, a Lebesgue sampling-based FDP (LS-FDP) is proposed. LS-FDP takes samples on the fault dimension axis and provides a need-based FDP philosophy in which the algorithm is executed only when necessary. In previous LS-FDP, the Lebesgue length is a constant. To accommodate the nonlinear fault dynamics, it is desirable to execute FDP algorithm more frequently when the fault growth is fast while less frequently when fault growth is slow. This requires to change the Lebesgue length adaptively and optimize the selection of Lebesgue length based on fault state and fault growth speed. The goal of this paper is to develop an improved LS-FDP method with adaptive Lebesgue length, which enables the FDP to be executed according to fault dynamics and has low cost in terms of computation and hardware resource needed. The design and implementation of adaptive LS-FDP (ALS-FDP) based on a particle filtering algorithm are illustrated with a case study of Li-ion batteries to verify the performances of the proposed approach. The experimental results show that ALS-FDP keeps close monitoring of fault growth and is accurate and time-efficient on long-term prognosis.Note to Practitioners—Traditional fault diagnosis and prognosis (FDP) approaches are based on the Riemann sampling (RS) method, in which samples are taken and algorithms are executed in periodic time intervals no matter if it is necessary. To reduce computation and make optimal use of computational resources, Lebesgue sampling method is introduced into FDP. In this Lebesgue sampling-based appr- ach, Lebesgue states are defined on the fault dimension axis and algorithm is executed only when the measurement causes a transition from one Lebesgue state to another, or an event happens. Different from RS-based approach, this is a need-based FDP philosophy in which the algorithm is executed only when necessary. This paper studies a parameter adaption method to optimally adjust the Lebesgue state length, which results in the changes of number and location of Lebesgue states, according to fault state and fault growth speed to accommodate the nonlinearity of fault dynamics and achieve a balance between computation and performance. The application to the capacity degradation of a set of Li-ion batteries is presented to demonstrate the effectiveness of the proposed adaptive Lebesgue state length FDP method. Auteurs: Wuzhao Yan;Bin Zhang;Wanchun Dou;Datong Liu;Yu Peng; Apparue dans: IEEE Transactions on Automation Science and Engineering Date publication: 10.-2017, volume: 14, issue:4, pages: 1601 - 1611 Editeur: IEEE Document complet vers site de l'éditeur
» Low-Loss Compact Silicon Nitride Arrayed Waveguide Gratings for Photonic Integrated Circuits
 Résumé:We report on low-loss, low-crosstalk, and compact arrayed waveguide gratings (AWGs) based on a 200-nm-thick-Si3 N4-core platform. High-resolution fabrication processes realized four types of Si3N4 AWG devices: 8 channel × 200 GHz, 16 channel × 100 GHz, 16 channel × 50 GHz, and 16 channel × 25 GHz AWGs. The insertion loss values of the four devices were 1.5 dB, 1.7 dB, 1.8 dB, and 2.7 dB; the corresponding crosstalk values were –24 dB, –21 dB, –20 dB, and –13 dB; footprints were 1.8 × 0.6 mm2, 2.2 × 0.7 mm2, 3.7 × 0.7 mm2, and 6.8 × 0.7 mm2, respectively. Auteurs: Kuanping Shang;Shibnath Pathak;Chuan Qin;S. J. Ben Yoo; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 5 Editeur: IEEE Document complet vers site de l'éditeur
» Low-Loss Connection of Embedded Optical Fiber Sensors Using a Self-Written Waveguide
 Résumé:This letter reports on a new concept for making a low-loss connection to an optical fiber sensor, which is embedded in a fiber reinforced composite material for structural health monitoring. First, a cross section of the composite is made to reveal the end-face of the embedded optical fiber. Then, an external fiber is aligned and an intermediate polymer-based self-written waveguide (SWW) is fabricated between both fibers. This SWW bridges the gap and serves as mode size converter ensuring a low-loss optical connection even if both fibers have dissimilar mode field diameters. The advantage of this approach is that no special care needs to be taken during the composite production cycle not to damage the sensor fiber in- or egress points, since it will be reconnected afterward. Auteurs: Jeroen Missinne;Geert Luyckx;Eli Voet;Geert Van Steenberge; Apparue dans: IEEE Photonics Technology Letters Date publication: 10.-2017, volume: 29, issue:20, pages: 1731 - 1734 Editeur: IEEE Document complet vers site de l'éditeur
» Low-Pass FSS for 50–230 GHz Quasi-Optical Demultiplexing for the MetOp Second-Generation Microwave Sounder Instrument
 Résumé:This paper reports the design, manufacture, and characterization of a new frequency selective surface (FSS) structure which meets the demanding requirements for transmission of 50.2–57.7 GHz radiation simultaneously for TE and TM polarizations at 45° incidence, and reflection of signals in four discrete higher frequency bands centered at 89, 165.5, 183.3, and 229 GHz. The FSS is required for a quasi-optical network, which was developed during the preparatory breadboarding of the microwave sounder instrument. The 100 mm diameter ultrawideband FSS must exhibit ≤0.25 dB loss for all signals in the above bands, and has to satisfy the requirements of the space environment. The FSS is formed by a periodic metal film array sandwiched between two 0.83 mm thick, optically flat, fused quartz substrates. It has 19 000 unit cells composed of two compact resonant slot elements, a meandering elliptical annulus and a folded dipole. Spectral transmission and reflection measurements in the 50–230 GHz frequency range yielded results that are in excellent agreement with numerical predictions. Auteurs: Raymond Dickie;Steven Christie;Robert Cahill;Paul Baine;Vincent Fusco;Kai Parow-Souchon;Manju Henry;Peter G. Huggard;Robert S. Donnan;Oleksandr Sushko;Massimo Candotti;Rostyslav Dubrovka;Clive G. Parini;Ville Kangas; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5312 - 5321 Editeur: IEEE Document complet vers site de l'éditeur
» Low-Power Digital Baseband Transceiver Design for UWB Physical Layer of IEEE 802.15.6 Standard
 Résumé:This paper presents the design and implementation of ultrawideband digital baseband transceiver for wireless body area networks (WBAN) applications. The power dissipation and area of the proposed architecture are minimized by combining algorithmic and architectural level modifications. A new algorithm for Bose–Chaudhuri–Hocquenghem (BCH) encoding is implemented and the coding gain of the BCH decoder is improved by 0.5 dB, with a cost of only one percent area overhead. An area efficient, low-complexity, and low-power BCH decoder is implemented and it has 42$\%$ lower area and 38$\%$ lower power dissipation compared to a conventional hard-decision decoder. Other salient features of this paper include a low-complexity, low-power packet detection unit, and a low-power module for removing the shortening bits. The baseband transceiver has been designed in 90 nm CMOS technology and it has an energy efficiency of 73 pJ/bit in transmitter mode and 225 pJ/bit in receiver mode. Auteurs: Pavan Kumar Manchi;Roy Paily;Anup Kumar Gogoi; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2474 - 2483 Editeur: IEEE Document complet vers site de l'éditeur
» Low-Power Transparent RFID Circuits Using Enhancement/Depletion Logic Gates Based on Deuterium-Treated ZnO TFTs
 Résumé:Transparent radio frequency identification (RFID) integrated circuits based on ZnO thin film transistors were developed by using ratioed logic gates with depletion loads. The fabrication of these logic gates employed a simple deuterium plasma treatment to adjust the threshold voltages of the load transistors. Inverters were realized with full swing (0.02 ~4.99V), high gain of −48V/V, large noise margin, and small area. RFID circuits based on such logic gates exhibited ultra-low power dissipation of $8.28~\mu \text{W}$ at a supply voltage of 2.4 V and a considerably high data rate of 1.6 kb/s, which may open up possibilities for applications including transparent, low-cost RFID tags. Auteurs: Hua Xu;Zhi Ye;Ni Liu;Ying Wang;Ning Zhang;Yang Liu; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1383 - 1386 Editeur: IEEE Document complet vers site de l'éditeur
» Low-Profile Distributed Cavity Resonators and Filters
 Résumé:In this paper, a new family of low-profile high quality factor cavity resonators, termed distributed resonators, is introduced. Initially, the theory of operation of the proposed distributed resonator is presented regarding two, three, and four coupled resonator elements. Based on this, a further-improved arrangement of resonator elements is proposed. It is shown that the height of the individual resonator can be controlled by the number of resonant elements and can be almost arbitrarily low. As an experimental verification, a three-pole filter operating at 1800 MHz with a bandwidth of 40 MHz is designed and fabricated. The individual resonator of this filter comprises 25 individual resonant elements, with an overall cavity height of 7 mm, or 15°, and an unloaded quality factor of 1900. The height of the presented filter is significantly lower than any other air-filled filter cavity solution available in the literature. The measured insertion loss of the filter is 0.5 dB, which is in excellent agreement with the theoretically predicted value of 0.4 dB. Auteurs: Senad Bulja;Martin Gimersky; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3769 - 3779 Editeur: IEEE Document complet vers site de l'éditeur
» Low-Rank-Based Nonlocal Adaptive Loop Filter for High-Efficiency Video Compression
 Résumé:In video coding, the in-loop filtering has emerged as a key module due to its significant improvement on compression performance since H.264/Advanced Video Coding. Existing incorporated in-loop filters in video coding standards mainly take advantage of the local smoothness prior model used for images. In this paper, we propose a novel adaptive loop filter utilizing image nonlocal prior knowledge by imposing the low-rank constraint on similar image patches for compression noise reduction. In the filtering process, the reconstructed frame is first divided into image patch groups according to image patch similarity. The proposed in-loop filtering is formulated as an optimization problem with low-rank constraint for every group of image patches independently. It can be efficiently solved by soft-thresholding singular values of the matrix composed of image patches in the same group. To adapt the properties of the input sequences and bit budget, an adaptive threshold derivation model is established for every group of image patches according to the characteristics of compressed image patches, quantization parameters, and coding modes. Moreover, frame-level and largest coding unit-level control flags are signaled to further improve the adaptability from the sense of rate-distortion optimization. The performance of the proposed in-loop filter is analyzed when it collaborates with the existing in-loop filters in High Efficiency Video Coding. Extensive experimental results show that our proposed in-loop filter can further improve the performance of state-of-the-art video coding standard significantly, with up to 16% bit-rate savings. Auteurs: Xinfeng Zhang;Ruiqin Xiong;Weisi Lin;Jian Zhang;Shiqi Wang;Siwei Ma;Wen Gao; Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology Date publication: 10.-2017, volume: 27, issue:10, pages: 2177 - 2188 Editeur: IEEE Document complet vers site de l'éditeur
» Low-VDD Operation of SRAM Synaptic Array for Implementing Ternary Neural Network
 Résumé:For Internet of Things (IoT) edge devices, it is very attractive to have the local sensemaking capability instead of sending all the data back to the cloud for information processing. For image pattern recognition, neuro-inspired machine learning algorithms have demonstrated enormous powerfulness. To effectively implement learning algorithms on-chip for IoT edge devices, on-chip synaptic memory architectures have been proposed to implement the key operations such as weighted-sum or matrix-vector multiplication. In this paper, we proposed a low-power design of static random access memory (SRAM) synaptic array for implementing a low-precision ternary neural network. We experimentally demonstrated that the supply voltage (VDD) of the SRAM array could be aggressively reduced to a level, where the SRAM cell is susceptible to bit failures. The testing results from 65-nm SRAM chips indicate that VDD could be reduced from the nominal 1–0.55 V (or 0.5 V) with a bit error rate ~0.23% (or ~1.56%), which only introduced ~0.08% (or ~1.68%) degradation in the classification accuracy. As a result, the power consumption could be reduced by more than $8\times$ (or $10\times$ ). Auteurs: Xiaoyu Sun;Rui Liu;Yi-Ju Chen;Hsiao-Yun Chiu;Wei-Hao Chen;Meng-Fan Chang;Shimeng Yu; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2962 - 2965 Editeur: IEEE Document complet vers site de l'éditeur
» LPM-Based Shielding Performance Analysis of High-Voltage Substations Against Direct Lightning Strokes
 Résumé:The leader progression model (LPM) is employed to investigate the shielding system performance of high-voltage substations against direct lightning strokes in the presence of substation instruments. The substation is simulated in detail for high accurate calculation of the shielding failure rate. Almost all of the apparatuses are modeled as fictitious charges in the stepwise simulations of LPM. The charge simulation method is used for finding the electrical field during the lightning movement. The probability of upward leader propagation is considered from all apparatuses. For more practical simulation, the environmental conditions are also included in simulations. The investigations are implemented on a test case and a practical high-voltage substation. The results are compared to those of the electrogeometric model. It is very likely that the results of this paper better simulate reality because lots of parameters have been taken into account. The results reveal that the presence of substation instruments increases the striking distance and the SF since they attract the lightning moving down near the substation. Auteurs: Abolfazl Rahiminejad;Behrooz Vahidi; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2218 - 2227 Editeur: IEEE Document complet vers site de l'éditeur
» LPPFusion to initiate fusion, the company's desktop device exploits instability [Resources_Startups]
 Résumé:Since nuclear fusion's earliest days, the sun has served as the ultimate prototype. It's the closest continuously functioning large-scale fusion reactor, after all. Why not copy from the best? So tokamaks, stellarators, and laser ignition facilities all strive to create high-pressure and high-temperature plasmas that behave like microcosms of the sun's core. One of the biggest challenges these systems face is achieving the tight control they require over the plasma fuel they seek to fuse. But one New Jersey fusion startup company is taking a very different tack: "Guide the plasma's instability; don't fight it," says Eric Lerner, president and chief scientist at LPPFusion, based in Middlesex, N.J. Auteurs: Mark Anderson; Apparue dans: IEEE Spectrum Date publication: 10.-2017, volume: 54, issue:10, pages: 17 - 18 Editeur: IEEE Document complet vers site de l'éditeur
» Lunar Brightness Temperature Model Based on the Microwave Radiometer Data of Chang’e-2
 Résumé:The brightness temperature (TB) data of the Moon acquired by the microwave radiometer (MRM) on-board the Chinese Chang’e-2 (CE-2) lunar probe are valuable and comprehensive data, which can be helpful in studying the physical properties of the lunar regolith, such as thickness, physical temperature, and dielectric constant. To construct the accurate and high-resolution lunar TB model with the TB data obtained by the MRM on-board CE-2, 2401 tracks of the original TB data are quantized by using the hour angle processing, and the hierarchical MK splines function (HMKSF) method is presented, which uses a hierarchy of coarse-to-fine control lattices to generate a sequence of TB model functions. The TB model constructor is the sum of the TB model functions derived at each level of the hierarchy. In addition, the lunar TB models with a resolution of $0.5 {^{\circ }} \times 0.5 {^{\circ }}$ in all four frequency channels are constructed for both the daytime and the nighttime. The obtained models show rich information, e.g., the global distribution of TB over the lunar surface, the effect of frequency on the TB model. Auteurs: Zhanchuan Cai;Ting Lan; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5944 - 5955 Editeur: IEEE Document complet vers site de l'éditeur
» Magnetic and Microwave Absorption Properties of Magnetite (Fe3O4)@Conducting Polymer (PANI, PPY, PT) Composites
 Résumé:Magnetite nanoparticles (Fe3O4 NPs) were synthesized via reflux co-precipitation method and coated with various polymeric media of polypyrrole (PPY), polyaniline (PANI), and polythiophene (PT) in the same experiment conditions. The increasing crystallinity and the absence of another phase were investigated from X-ray diffraction experiments. Fe3O4 NPs have spherical shapes and after polymer coating their mean size were found as 11.76, 11.51, and 9.98 nm for Fe3O4@PPY, Fe3O4@PANI, and Fe3O4@PT, respectively. The superparamagnetic nature of composites was observed at room temperature. The electromagnetic (EM) wave reflection loss of samples was analyzed comparatively. It was found that the type of the polymers coated on the magnetite nanoparticles in the same procedure gives slight change in reflection loss of EM waves. Auteurs: Ibrahim Saim Unver;Zehra Durmus; Apparue dans: IEEE Transactions on Magnetics Date publication: 10.-2017, volume: 53, issue:10, pages: 1 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» Magnetic Guidance [Turnstile]
 Résumé:Discusses the role that magnetic-aerotactic bacteria will play in the field of medicine. Auteurs: Rajeev Bansal; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 10.-2017, volume: 59, issue:5, pages: 138 - 138 Editeur: IEEE Document complet vers site de l'éditeur
» Magnetoresistance Relaxation Anisotropy of Nanostructured La-Sr(Ca)-Mn-O Films Induced by High-Pulsed Magnetic Fields
 Résumé:The results of investigation of colossal magnetoresistance relaxation in nanostructured La-Sr(Ca)-Mn-O films upon removal of magnetic field pulse are presented. Thin films having thicknesses of 75–350 nm grown by pulsed injection metal–organic chemical vapor deposition technique were studied in pulsed magnetic fields having duration of 0.9 ms and amplitudes of 2–12 T. It was obtained that “fast” relaxation process occurring in hundred microseconds time scale exhibits anisotropy: the magnitude of remnant resistivity is approximately three times smaller and the process is faster when magnetic field is applied perpendicular to the film plane in comparison with in-plane direction. The dynamics of this relaxation process was analyzed using Kolmogorov–Avrami–Fatuzzo model, taking into account nucleation and reorientation of magnetic domains into equilibrium state. The “fast” remnant relaxation was not observed after the application of longer pulses (20 ms) having amplitude of 60 T. Influence of remnant relaxation on operation of B-scalar magnetic field sensors based on nanostructured manganite films is discussed. Auteurs: Nerija Žurauskienė;Dainius Pavilonis;Jonas Klimantavičius;Saulius Balevičius;Voitech Stankevič;Remigijus Vasiliauskas;Valentina Plaušinaitienė;Adulfas Abrutis;Martynas Skapas;Remigijus Jušk Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2773 - 2779 Editeur: IEEE Document complet vers site de l'éditeur
» Major Trends Impacting Power Systems [From the Editor's Desk]
 Résumé:Presents the introductory editorial for this issue of the publication. Auteurs: Lanny Floyd; Apparue dans: IEEE Industry Applications Magazine Date publication: 10.-2017, volume: 23, issue:5, pages: 3 - 3 Editeur: IEEE Document complet vers site de l'éditeur
» Majority Logic Decoding Under Data-Dependent Logic Gate Failures
 Résumé:A majority logic decoder made of unreliable logic gates, whose failures are transient and data-dependent, is analyzed. Based on a combinatorial representation of fault configurations a closed-form expression for the average bit error rate for a one-step majority logic decoder is derived, for a regular low-density parity-check (LDPC) code ensemble and the proposed failure model. The presented analysis framework is then used to establish bounds on the one-step majority logic decoder performance under the simplified probabilistic gate-output switching model. Based on the expander property of Tanner graphs of LDPC codes, it is proven that a version of the faulty parallel bit-flipping decoder can correct a fixed fraction of channel errors in the presence of data-dependent gate failures. The results are illustrated with numerical examples of finite geometry codes. Auteurs: Srdan Brkic;Predrag Ivaniš;Bane Vasić; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6295 - 6306 Editeur: IEEE Document complet vers site de l'éditeur
» Make the web better for everyone [Spectral Lines]
 Résumé:The Web has serious problems: peddler of unreliable information, haven for criminals, spawning ground for irrational conspiracy fears, and tool for destructive people to broadcast their violence in real time and with posted recordings. No doubt your list of Web pathologies is different from mine. But surely you agree that the Web disappoints as much as it delights. Now the hard part-what to do about it? Starting over is impossible. The Web is the ground of our global civilization, a pillar of contemporary existence. Even as we complain about the excesses and shortcomings of the Web, we can't survive without it. For engineers and technovisionaries, the solution flows from an admirable U.S. tradition: building a better mousetrap. For redesigners of the broken Web, the popular impulse is to expand digital freedom by creating a Web so decentralized that governments can't censor it and big corporations can't dominate. However noble, the freedom advocates fail to account for a major class of vexations arising from anonymity, which allows, say, Russian hackers to pose as legitimate tweeters and terrorist groups to recruit through Facebook pages. To be sure, escape from government surveillance through digital masks has benefits, yet the path to improved governance across the world doesn't chiefly lie with finding more clever ways to hide from official oppression. More freedom, ultimately, will only spawn more irresponsible, harmful behavior. If more freedom and greater privacy won't cure what ails the Web, might we consider older forms of control and the cooperation of essential public services? Auteurs: G. Pascal Zachary; Apparue dans: IEEE Spectrum Date publication: 10.-2017, volume: 54, issue:10, pages: 8 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» Mandatory Content Access Control for Privacy Protection in Information Centric Networks
 Résumé:Several Information Centric Network (ICN) architectures have been proposed as candidates for the future Internet, aiming to solve several salient problems in the current IP-based Internet architecture such as mobility, content dissemination and multi-path forwarding. In general, security and privacy are considered as essential requirements in ICN. However, existing ICN designs lack built-in privacy protection for content providers (CPs), e.g., any router in an Internet Service Provider in ICN can cache any content, which may result in information leakage. In this paper, we propose Mandatory Content Access Control (MCAC), a distributed information flow control mechanism to enable a content provider to control which network nodes can cache its contents. In MCAC, a CP defines different security labels for different contents, and content routers check these labels to decide if a content object should be cached. To ensure correct enforcement of MCAC, we also propose a design of a trusted architecture by extending existing mainstream router architectures. We evaluate the performance of MCAC in the NS-3 simulator. The simulation results show that enforcing MCAC in routers does not introduce significant overhead in content forwarding. Auteurs: Qi Li;Ravi Sandhu;Xinwen Zhang;Mingwei Xu; Apparue dans: IEEE Transactions on Dependable and Secure Computing Date publication: 10.-2017, volume: 14, issue:5, pages: 494 - 506 Editeur: IEEE Document complet vers site de l'éditeur
» Manifold Learning by Curved Cosine Mapping
 Résumé:In the field of pattern recognition, data analysis, and machine learning, data points are usually modeled as high-dimensional vectors. Due to the curse-of-dimensionality, it is non-trivial to efficiently process the orginal data directly. Given the unique properties of nonlinear dimensionality reduction techniques, nonlinear learning methods are widely adopted to reduce the dimension of data. However, existing nonlinear learning methods fail in many real applications because of the too-strict requirements (for real data) or the difficulty in parameters tuning. Therefore, in this paper, we investigate the manifold learning methods which belong to the family of nonlinear dimensionality reduction methods. Specifically, we proposed a new manifold learning principle for dimensionality reduction named Curved Cosine Mapping (CCM). Based on the law of cosines in Euclidean space, CCM applies a brand new mapping pattern to manifold learning. In CCM, the nonlinear geometric relationships are obtained by utlizing the law of cosines, and then quantified as the dimensionality-reduced features. Compared with the existing approaches, the model has weaker theoretical assumptions over the input data. Moreover, to further reduce the computation cost, an optimized version of CCM is developed. Finally, we conduct extensive experiments over both artificial and real-world datasets to demonstrate the performance of proposed techniques. Auteurs: Huamao Gu;Xun Wang;Xuewen Chen;Shaoping Deng;Jinqin Shi; Apparue dans: IEEE Transactions on Knowledge and Data Engineering Date publication: 10.-2017, volume: 29, issue:10, pages: 2236 - 2248 Editeur: IEEE Document complet vers site de l'éditeur
» Manipulation and Transportation With Cooperative Underwater Vehicle Manipulator Systems
 Résumé:Autonomous underwater manipulation has been a topic of interest since the early 1990s. In the past few years, several milestone projects such as SAUVIM and TRIDENT have demonstrated autonomy capabilities for a single underwater vehicle manipulator system (UVMS) in performing simple manipulation tasks, e.g., the recovery of an object from the seafloor. The Italian funded MARIS project aims to extend some of these results to multiple UVMSs performing a cooperative transportation task of a long object such as a pipe. This paper presents the results achieved in developing a unifying architecture for the control of both individually and cooperatively operating UVMSs which explicitly makes use of a limited amount of information exchange between the agents, which is needed due to the severe bandwidth limitations of the underwater acoustic communications. A complete execution of the reference transportation mission is presented to support the proposed distributed algorithm. Furthermore, hydrodynamic simulations of the cooperative transportation phase are presented and an analysis of the achievable performances as different communication schemes are employed is given. Auteurs: Enrico Simetti;Giuseppe Casalino; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 782 - 799 Editeur: IEEE Document complet vers site de l'éditeur
» Marx Multilevel Bipolar Modulator Dynamic Models for Load Transient Analysis
 Résumé:This paper presents generalized dynamic models for Marx derived multilevel half-bridge bipolar modulators. This high-voltage topology uses modular Marx multilevel converter diode ( $\text{M}^{\mathrm {{3}}}$ CD) cells to generate positive and negative (bipolar) pulses or unipolar (positive or negative voltage pulses). The developed models are tested in transient studies of pulse voltages and currents in the load. Simulation and experimental results are presented and compared. Auteurs: L. Lamy Rocha;J. Fernando Silva;L. M. Redondo; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2611 - 2617 Editeur: IEEE Document complet vers site de l'éditeur
» Mathematical Modeling and Parameter Optimization of Fine Particle Sensors Based on Laser Light Scattering
 Résumé:Fine particles have promoted air quality monitoring need of humankind after their harmful effects on human health are pathologically verified. To monitor fine particle concentrations at a low cost, laser light scattering technique is favored by many researchers. While several cheap and interesting sensors are developed, little attention is paid to the measurement model, which in turn bound the sensor precision. In order to alleviate this situation, a simplified model is proposed, which can describe the nonlinear relationship between particle volume and single particle angular light flux by considering the effect of Rayleigh scattering and Fraunhofer diffraction simultaneously. The model can be employed in the signal processing of commercial low-cost particle sensors based on laser light scattering. A data-driven approach is adopted to find the optimum parameters of this model by considering different kinds of fine particles. Based on Trust-Region and Levenberg-Marquardt methods combining with robust methods, the optimum parameters of this model are obtained. To verify the effectiveness of the proposed model, comparative experiments are conducted on: a particle sensor with and without parameter optimization, a DustTrak II 8530 monitor and a reference TEOM PM2.5 monitor. The results indicated that the optimal model improves the measurement accuracy of the fine particle mass concentration by 10%. Auteurs: Wenjia Shao;Hongjian Zhang;Hongliang Zhou; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6672 - 6681 Editeur: IEEE Document complet vers site de l'éditeur
» MATLAB-Based Interactive Tool for Teaching Electromagnetics [Education Corner]
 Résumé:Presents information on the MATLAB-Based Interactive tool for teaching electromagnetics. This was created for a second-year university-level electromagnetics course using a MATLAB-based graphical user interface (GUI). It aims to improve learning outcomes, reduce staff workload, and engage online students through blended learning. The tool allows for the random generation of inputs for a large number of problems, provides automatic feedback when the answers are incorrect, and generates a report when the answers are correct. Examples of electrostatics, magnetostatics, dynamic fields, and transmission lines problem sets are presented. Auteurs: Hugo G. Espinosa;David V. Thiel; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 10.-2017, volume: 59, issue:5, pages: 140 - 146 Editeur: IEEE Document complet vers site de l'éditeur
» Maximum Likelihood Estimation of Functionals of Discrete Distributions
 Résumé:We consider the problem of estimating functionals of discrete distributions, and focus on a tight (up to universal multiplicative constants for each specific functional) nonasymptotic analysis of the worst case squared error risk of widely used estimators. We apply concentration inequalities to analyze the random fluctuation of these estimators around their expectations and the theory of approximation using positive linear operators to analyze the deviation of their expectations from the true functional, namely their bias. We explicitly characterize the worst case squared error risk incurred by the maximum likelihood estimator (MLE) in estimating the Shannon entropy $H(P) = \sum _{i = 1}^{S} -p_{i} \ln p_{i}$ , and the power sum $F_\alpha (P) = \sum _{i = 1}^{S} p_{i}^\alpha ,\alpha >0$ , up to universal multiplicative constants for each fixed functional, for any alphabet size $S\leq \infty$ and sample size $n$ for which the risk may vanish. As a corollary, for Shannon entropy estimation, we show that it is necessary and sufficient to have $n \gg S$ observations for the MLE to be consistent. In addition, we establish that it is necessary and sufficient to consider $n \gg S^{1/\alpha }$ samples for the MLE to consistently estimate $F_\alpha (P), 0<\alpha <1$ . The minimax rate-optimal estimators for both problems require $S/\ln S$ and $S^{1/\alpha }/\ln S$ samples, which implies that the MLE has a strictly sub-optimal sample complexity. When $1<\alpha <3/2$ , we show that the worst case squared error rate of convergence for the MLE is $n^{-2(\alpha -1)}$ for infinite alphabet size, while the minimax squared error rate is $(n\ln n)^{-2(\alpha -1)}$ . When $\alpha \geq 3/2$ , the MLE achieves the minimax optimal rate $n^{-1}$ regardless of the alphabet size. As an application of the general theory, we analyze the Dirichlet prior smoothing techniques for Shannon entropy estimation. In this context, one approach is to plug-in the Dirichlet prior smoothed distribution into the entropy functional, while the other one is to calculate the Bayes estimator for entropy under the Dirichlet prior for squared error, which is the conditional expectation. We show that in general such estimators do not improve over the maximum likelihood estimator. No matter how we tune the parameters in the Dirichlet prior, this approach cannot achieve the minimax rates in entropy estimation. The performance of the minimax rate-optimal estimator with $n$ samples is essentially at least as good as that of Dirichlet smoothed entropy estimators with $n\ln n$ samples. Auteurs: Jiantao Jiao;Kartik Venkat;Yanjun Han;Tsachy Weissman; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6774 - 6798 Editeur: IEEE Document complet vers site de l'éditeur
» Maximum Versoria Criterion-Based Robust Adaptive Filtering Algorithm
 Résumé:Using the generalized Gaussian probability density function as the kernel, a generalized correntropy has been proposed. A generalized maximum correntropy criterion (GMCC) algorithm is then developed by maximizing the generalized correntropy. However, the GMCC algorithm has a high steady-state misalignment and involves a high calculation cost of the exponential term (generalized Gaussian kernel). In this brief, we propose a maximum Versoria criterion (MVC) algorithm, which is derived by maximizing the generalized Versoria function, to reduce steady-state misalignment and computational effort as compared to the GMCC algorithm. The MVC algorithm is then tested in system identification and acoustic echo cancellation scenarios, which have demonstrated that the proposed algorithm is robust against non-Gaussian impulsive noises and performs much better than the LMP and GMCC algorithms. Auteurs: Fuyi Huang;Jiashu Zhang;Sheng Zhang; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1252 - 1256 Editeur: IEEE Document complet vers site de l'éditeur
» Measurement of the Ionospheric Scintillation Parameter $C_{k}L$ From SAR Images of Clutter
 Résumé:Space-based synthetic aperture radar (SAR) can be affected by the ionosphere, particularly at L-band and below. A technique is described that exploits the reduction in SAR image contrast to measure the strength of ionospheric turbulence parameter ${C}_{k}{L}$ . The theory describing the effect of the ionosphere on the SAR point spread function (PSF) and the consequent effect on clutter is reviewed and extended. This theory can then be used to determine ${C}_{k}{L}$ from both corner reflectors (CRs) and K-distributed SAR clutter. Measuring the K-distribution order parameter allows ${C}_{k}{L}$ values much lower than those that defocus the image to be determined. The results of an experiment in which a CR on Ascension Island was repeatedly imaged by PALSAR-2 in the spotlight mode during the scintillation season are described. The value of ${C}_{k}{L}$ obtained by measuring the clutter was compared with that obtained from a nearby CR. The correlation between the two was good using a median value of the spectral index $p$ . This correlation was improved by using the measured value of $p$ derived from the CR PSF. The technique works for any homogeneous K-distributed SAR clutter and is thus applicable to extra-terrestrial bodies as well as PALSAR-2 images of Ascension Island. Auteurs: David P. Belcher;Christopher R. Mannix;Paul S. Cannon; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5937 - 5943 Editeur: IEEE Document complet vers site de l'éditeur
» Meetings calendar
 Résumé:Provides a listing of future meetings. Auteurs: Davide Fabiani; Apparue dans: IEEE Electrical Insulation Magazine Date publication: 10.-2017, volume: 33, issue:5, pages: 60 - 62 Editeur: IEEE Document complet vers site de l'éditeur
» Memory Unscented Particle Filter for 6-DOF Tactile Localization
 Résumé:This paper addresses 6-DOF (degree-of-freedom) tactile localization, i.e., the pose estimation of tridimensional objects using tactile measurements. This estimation problem is fundamental for the operation of autonomous robots that are often required to manipulate and grasp objects whose pose is a priori unknown. The nature of tactile measurements, the strict time requirements for real-time operation, and the multimodality of the involved probability distributions pose remarkable challenges and call for advanced nonlinear filtering techniques. Following a Bayesian approach, this paper proposes a novel and effective algorithm, named memory unscented particle filter (MUPF), which solves 6-DOF localization recursively in real time by only exploiting contact point measurements. The MUPF combines a modified particle filter that incorporates a sliding memory of past measurements to better handle multimodal distributions, along with the unscented Kalman filter that moves the particles toward regions of the search space that are more likely with the measurements. The performance of the proposed MUPF algorithm has been assessed both in simulation and on a real robotic system equipped with tactile sensors (i.e., the iCub humanoid robot). The experiments show that the algorithm provides accurate and reliable localization even with a low number of particles and, hence, is compatible with real-time requirements. Auteurs: Giulia Vezzani;Ugo Pattacini;Giorgio Battistelli;Luigi Chisci;Lorenzo Natale; Apparue dans: IEEE Transactions on Robotics Date publication: 10.-2017, volume: 33, issue:5, pages: 1139 - 1155 Editeur: IEEE Document complet vers site de l'éditeur
» MEMS Logic Using Mixed-Frequency Excitation
 Résumé:We present multi-function microelectromechanical systems (MEMS) logic device that can perform the fundamental logic gate AND, OR, universal logic gates NAND, NOR, and a tristate logic gate using mixed-frequency excitation. The concept is based on exciting combination resonances due to the mixing of two or more input signals. The device vibrates at two steady states: a high state when the combination resonance is activated and a low state when no resonance is activated. These vibration states are assigned to logical value 1 or 0 to realize the logic gates. Using ac signals to drive the resonator and to execute the logic inputs unifies the input and output wave forms of the logic device, thereby opening the possibility for cascading among logic devices. We found that the energy consumption per cycle of the proposed logic resonator is higher than those of existing technologies. Hence, integration of such logic devices to build complex computational system needs to take into consideration lowering the total energy consumption. [2017-0041] Auteurs: Saad Ilyas;Nizar Jaber;Mohammad I. Younis; Apparue dans: Journal of Microelectromechanical Systems Date publication: 10.-2017, volume: 26, issue:5, pages: 1140 - 1146 Editeur: IEEE Document complet vers site de l'éditeur
» mGate: A Universal Magnetologic Gate for Design of Energy Efficient Digital Circuits
 Résumé:This paper presents a universal magnetologic gate, the so-called magnetogate (mGate) for the design of energy efficient digital circuits. The mGate employs magnetic tunnel junction (MTJ) cells, which have valuable features such as non-volatility, lower power consumption, and higher integration density compared with transistor-based gates. mGate can be efficiently exploited to the design of different combinational and sequential logic circuits. HSPICE-based simulations have been carried out to verify the correct functionality of different mGate-based circuits. The simulation results reveal that the mGate provides low area, power consumption, and energy while also offering more flexibility as compared with previously proposed MTJ-based designs. Auteurs: Vahid Jamshidi;Mahdi Fazeli;Ahmad Patooghy; Apparue dans: IEEE Transactions on Magnetics Date publication: 10.-2017, volume: 53, issue:10, pages: 1 - 13 Editeur: IEEE Document complet vers site de l'éditeur
» Microfluidically Reconfigurable Microstrip Line Combline Filters With Wide Frequency Tuning Capabilities
 Résumé:Microfluidically repositionable selectively metallized plates (SMPs) are utilized for the first time to design and realize microstrip line combline filters with wide frequency tuning and high power-handling capability. A continuous frequency tuning range of 2.7:1 is achieved by utilizing tight coupling between the SMP and open-ended microstrip line resonators in order to change their length for tuning from 2.5 to 4 GHz and capacitively load one of their open ends for tuning from 1.5 to 2.5 GHz. The unloaded quality factor (Qu) of the resonators is maintained relatively constant (210–190) across the entire tuning range allowing for the low insertion loss (IL) and high power-handling capability. Specifically, a ~5% constant fractional bandwidth fourth-order filter design is discussed and experimentally verified. The filter exhibits less than 3-dB IL across the 2.7:1 tuning range. It is shown that the filter’s power handling capability can reach up to 15 W under constant average power excitation. Auteurs: Timothy Palomo;Gokhan Mumcu; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3561 - 3568 Editeur: IEEE Document complet vers site de l'éditeur
» Microstructural Effects on Nickel Oxide Film Properties in an Infrared Electrochromic Window for Shutter-Less Infrared Sensor Application
 Résumé:Infrared electrochromic devices (ECDs) were fabricated and characterized in mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) ranges. They consisted of three layers with two metal electrodes. The layers were an ion storage layer, an ion conducting layer, and an electrochromic layer. As an ion storage layer, NiO film was used. To ensure higher performance of the ECDs, the microstructural and electrochromic properties of NiO films deposited at various sputtering pressures were investigated using SEM, X-ray photoelectron spectroscopy, and cyclic voltammetry. In addition, WO3 film and Ta2O5 film were used in the two types of fabricated devices as a cathodic electrochromic layer and an ion conducting layer, respectively. The transmittance values in the MWIR and LWIR ECDs were measured in colored and bleached states. The measured transmittance ratios of the colored state relative to the bleached state were 0.66 and 0.72 in the MWIR and LWIR ranges, respectively. Auteurs: Hyun Bin Shim;Woo Young Kim;In-Ku Kang;Hee Chul Lee; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6522 - 6528 Editeur: IEEE Document complet vers site de l'éditeur
» Microwave Annealing as a Low Thermal Budget Technique for ZnO Thin-Film Transistors Fabricated Using Atomic Layer Deposition
 Résumé:Microwave annealing (MWA) and furnace annealing are compared for their low thermal budget capability to improve the characteristics of ZnO-based thin-film transistors (TFTs). Both the ZnO channel and the Al2O3 gate dielectric are fabricated using atomic layer deposition. Using Si-wafer-susceptor assisted MWA with a substantial reduction of both annealing temperature and duration, significant improvements of the characteristics of the ZnO TFTs can be attained. A multi-step MWA process is found to further improve the characteristics of the TFTs. For the same microwave power and total duration, the field-effect mobility of the multi-step MWA TFT is 42% greater than that of the one-step MWA TFT with a similar sub-threshold swing. The multi-step MWA process can serve the purpose at temperatures as low as 220 °C. Auteurs: Lei Yue;Chao-Chao Fu;Feng Sun;Zhi-Jun Qiu;Shi-Li Zhang;Dongping Wu; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1390 - 1393 Editeur: IEEE Document complet vers site de l'éditeur
» Microwave Imaging From Sparse Measurements for Near-Field Synthetic Aperture Radar
 Résumé:This paper reports the experimental studies for four image reconstruction methods from sparse measurement using wideband microwave synthetic aperture radar systems. The four methods include two denoising methods using zero filling (ZF) and nonuniform fast Fourier transform (NUFFT), and two compressed sensing (CS) methods using the orthogonal matching pursuit and the conjugate gradient algorithms. The specimens under test (SUTs) consist of a tray of small rocks with different densities with/without one piece wrapped in an aluminum foil. The raw measurements of the SUTs are randomly undersampled in the spatial domain, and the images are reconstructed from the measurements of 10%–60% sparse-sampling rates. The results show that the CS method achieves good image quality with as low as 30% sparse-sampling rate, while ZF and NUFFT require 50% to obtain acceptable quality. An enhanced Otsu’s method is also proposed to detect the foiled rock from sparse reconstructions, which improves detection performance for the sparse-sampling rate of 5%–15%. The reduction of spatial measurement leads to reduced cost or reduced measurement time. Auteurs: Xiahan Yang;Yahong R. Zheng;Mohammad Tayeb Ghasr;Kristen M. Donnell; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2680 - 2692 Editeur: IEEE Document complet vers site de l'éditeur
» Microwave Microfluidic Sensor Based on a Microstrip Splitter/Combiner Configuration and Split Ring Resonators (SRRs) for Dielectric Characterization of Liquids
 Résumé:A microwave microfluidic sensor for dielectric characterization of liquids in real time is presented in this paper. The sensor is implemented in microstrip technology and consists of a symmetric splitter/combiner configuration loaded with a pair of identical split ring resonators (SRRs) and microfluidic channels placed on top of them (gap region). The sensor works in differential mode and sensing is based on frequency splitting. Thus, if the structure is unloaded or if it is symmetrically loaded with regard to the axial plane, only one transmission zero (notch) in the frequency response appears. However, if the axial symmetry is disrupted (e.g., by the presence of different liquids in the channels), two transmission zeros arise, and the difference in magnitude (notch depth) and frequency between such transmission zeros is indicative of the difference in the dielectric properties (complex dielectric constant). A circuit schematic, including transmission line sections to describe the distributed components, lumped elements to account for the SRRs and their coupling to the lines and lumped elements to model the liquid properties, is presented and validated. After proper calibration, the functionality of the proposed sensor is demonstrated by measuring the complex permittivity in solutions of deionized water and ethanol as a function of the ethanol content. Auteurs: Paris Vélez;Lijuan Su;Katia Grenier;Javier Mata-Contreras;David Dubuc;Ferran Martín; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6589 - 6598 Editeur: IEEE Document complet vers site de l'éditeur
» Microwave Photonic Filtering for Interrogating FBG-Based Multicore Fiber Curvature Sensor
 Résumé:We propose and experimentally demonstrate an approach to perform high-resolution and temperature-insensitive interrogation of a fiber Bragg grating (FBG)-based multicore fiber (MCF) curvature sensor using a microwave photonics filtering technique. By combining two reflected sample signals from the two FBGs inscribed in MCF and a dispersion device, a two-tap notch microwave photonic filter (MPF) is formed. The notch frequency of MPF is dependent on the time delay difference between the two FBG reflected signals, which is related to wavelength spacing of the two FBGs. Due to the wavelength spacing of the two FBGs is proportional to the curvature, the curvature can be readily interrogated by monitoring the notch frequency of MPF. The proposed interrogation scheme with the sensitivity of 92 MHz/ $\text{m}^{-1}$ is achieved, whilst the sensitivity can be easily adjusted. Moreover, the proposed interrogation scheme is temperature insensitive. Auteurs: Di Zheng;Javier Madrigal;David Barrera;Salvador Sales;Jose Capmany; Apparue dans: IEEE Photonics Technology Letters Date publication: 10.-2017, volume: 29, issue:20, pages: 1707 - 1710 Editeur: IEEE Document complet vers site de l'éditeur
» Microwave Photonic Frequency Tripler Based on an Integrated Dual-Parallel Modulator Structure
 Résumé:A new technique for tripling the frequency of a microwave signal is presented. It is based on an integrated dual-parallel Mach–Zehnder modulator, which generates two orthogonally polarised RF modulated optical signals with different modulation indexes, and a polarisation-dependent optical attenuator. The photodetector output fundamental RF components generated by the two orthogonally polarised RF modulated optical signals have the same amplitude but an opposite phase, which are cancelled, leaving the frequency tripled microwave signal and the unwanted fifth order harmonic. The new frequency tripler has a simple structure, a wide bandwidth, and a high electrical spurious suppression ratio. Experimental results are presented demonstrating three times frequency multiplication of different-frequency microwave signals with electrical spurious suppression ratio of over 20 dB. The phase noise and the stability performance of the frequency tripler are also investigated experimentally. Auteurs: Chongjia Huang;Hao Chen;Erwin Hoi Wing Chan; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 10 Editeur: IEEE Document complet vers site de l'éditeur
» Microwave Power System Based on a Combination of Two Magnetrons
 Résumé:Currently, microwave energy is utilized for many diverse industrial applications because of its various advantages including its eco-friendliness. Low-cost, high-efficiency, and high-power industrial microwave sources are in urgent demand. In this paper, we propose a low-cost quasi-coherent power-combining system based on a combination of two magnetrons. We have analyzed and built a low-loss waveguide-based applicator combined with specific phase. This system utilizes the coupling of the combiner to quasi-lock the slave magnetron. A waveguide phase shifter lies in the slave magnetron branch to adjust the phase difference between the master and slave magnetrons’ signals to achieve high resultant efficiency. Based on theory, the phase difference between the master and the injected slave magnetrons has been numerically calculated and analyzed. The phase difference changes periodically when the slave magnetron is quasi-locked to the master magnetron and the periodicity increases with the injection ratio. Experimental results show the resultant efficiency of the proposed system can reach as high as 92% when using several suitable waveguide components. The investigation also provides guidelines for further microwave power combination systems with multiple sources. Auteurs: Yi Zhang;Kama Huang;Dinesh K. Agrawal;Tania Slawecki;Huacheng Zhu;Yang Yang; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4272 - 4278 Editeur: IEEE Document complet vers site de l'éditeur
» Microwave Sensors in Your Life [From the Guest Editors' Desk]
 Résumé:The articles in this special section addresses microwave sensor technology and discusses applications for its use. Radar sensors for military or automotive purposes and airport body scanners are examples that have gained wide interest, and the technology behind these has already been presented several times in the magazine. However, a significant number of microwave sensors used in our daily lives are not so well known to the average person because they are, for example, hidden behind walls or integrated into technical equipment. Auteurs: Reinhard Knöchel;Christian Damm;W. Gregory Lyons; Apparue dans: IEEE Microwave Magazine Date publication: 10.-2017, volume: 18, issue:6, pages: 24 - 25 Editeur: IEEE Document complet vers site de l'éditeur
» Microwave Thermal Emission Characteristics of a Two-Layer Medium With Rough Interfaces Using the Second-Order Small Perturbation Method
 Résumé:The second-order small perturbation method is applied to investigate brightness temperature corrections caused by the rough interfaces of a two-layer medium. The spectral weighting functions of the two rough interfaces are extracted from the solution, and their properties examined. It is found that the functions are identical for the two interfaces as the spectral variable approaches zero, indicating an identical weighting of the surface height variance on each interface and an additive effect on the brightness temperature at nadir. Sample results for some realistic scenarios show that surface roughness in a two-layer medium can increase or decrease the observed brightness temperature at shallower angles, and in the case of a wideband measurement, can shift the interference pattern in frequency. Auteurs: R. J. Burkholder;J. T. Johnson;M. Sanamzadeh;L. Tsang;S. Tan; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1780 - 1784 Editeur: IEEE Document complet vers site de l'éditeur
» Microwave Tomography for Industrial Process Imaging: Example Applications and Experimental Results.
 Résumé:This article describes the implementation of microwave tomography for industrial process applications. Microwave tomography for industrial process imaging has different requirements from that for medical imaging. In addition to spatial resolution, high temporal resolution or real-time imaging is also important for high-speed processes, flows, or rapid reactions. Depending on the specific application, both quantitative imaging and qualitative imaging may be needed. Qualitative imaging would be sufficient to display distributions, patterns, or shapes, which may be adequate for some applications. Quantitative imaging would, however, be more informative, giving images with quantitative dielectric contrast or permittivity values from which other physical parameters, such as density, moisture content, and phase fraction, may be derived. With the microwave tomography approach described, several example applications in industrial processes are demonstrated, and a number of experimental imaging results are presented. Auteurs: Zhipeng Wu;Haigang Wang; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 10.-2017, volume: 59, issue:5, pages: 61 - 71 Editeur: IEEE Document complet vers site de l'éditeur
» Millimeter-Wave Imaging of Surface-Breaking Cracks in Steel With Severe Surface Corrosion
 Résumé:Robust detection of surface-breaking (fatigue) cracks in metals with severe surface corrosion (rust) and pitting is of great practical interest. Detection of surface-breaking cracks in the millimeter-wave frequency range (30–300 GHz) has received considerable attention in the past two decades. At these frequencies, corrosion byproducts (rust) are in the family of dielectric materials allowing millimeter-wave signals to penetrate through and interact with a visually masked crack. When using open-ended rectangular waveguides, no contact is required, and the crack signal characteristics are significantly different than those from corrosion and pitting, which renders a crack detectable even in the presence of severe corrosion. Moreover, synthetic aperture radar images of cracks masked by corrosion can be rapidly generated providing additional geometrical information. This paper presents the results of uniquely combining these two methods for detecting cracks in severely corroded steel plates and for other similar applications where a crack is visually masked by a dielectric layer. Auteurs: John R. Gallion;Reza Zoughi; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2789 - 2791 Editeur: IEEE Document complet vers site de l'éditeur
» MIMO Antenna Using Hybrid Electric and Magnetic Coupling for Isolation Enhancement
 Résumé:This paper presents a multiple-input and multiple-output antenna using a wideband decoupling structure for enhancing isolation. The decoupling structure is formed by a split ring, which consists of an inductive line and a capacitive gap to realize magnetic and electric coupling, respectively. By introducing the electric coupling in addition to the magnetic coupling, more degrees of freedom are obtained and the original coupling between antennas can be canceled out within a wide frequency band. Meanwhile, the performance of each antenna element is maintained, such as impedance bandwidth and radiation characteristics. Theoretical analysis and experimental verification are carried out. When the decoupling structure is placed between these two monopole antennas with edge-to-edge space of only 5 mm ( $0.04\lambda _{0}$ at 2.5 GHz), more than 20 dB isolation is realized over the bandwidth of 2.3–2.9 GHz (24%) with $S_{11}$ and $S_{22}$ less than −10 dB. Moreover, the isolation levels reach more than 30 dB over the frequency band of 2.3–2.8 GHz. Compared with the previous related works using decoupling networks and neutralization line techniques, the proposed decoupling structure can provide higher isolation of over 30 dB in a wider bandwidth. Auteurs: Cheng-Dai Xue;Xiu Yin Zhang;Yun Fei Cao;Zhangju Hou;Chao Feng Ding; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5162 - 5170 Editeur: IEEE Document complet vers site de l'éditeur
» Minimal Perfect Hashing-Based Information Collection Protocol for RFID Systems
 Résumé:For large-scale RFID systems, this paper studies the practically important problem of target tag information collection, which aims at collecting information from a specific set of target tags instead of all. However, the existing solutions are of low time-efficiency because of two reasons. First, the serious collisions among tags due to hashing randomness seriously reduce the frame utilization, whose upper bound is just 36.8 percent. Second, they cannot efficiently distinguish the target tags from the non-target tags and thus inevitably collect a lot of irrelevant information on non-target tags, which further deteriorates the effective utilization of the time frame. To overcome the above two drawbacks, this paper proposes the minimal Perfect hashing-based Information Collection (PIC) protocol, which first leverages lightweight indicator vectors to establish a one-to-one mapping between target tags and slots, thereby improving the frame utilization to nearly 100 percent; and then uses the novel data structure called Minimal Perfect Hashing based Filter (MPHF) to filter out the non-target tags, thereby preventing them from interfering with the process of collecting information from target tags. Sufficient theoretical analyses are also presented in this paper to minimize the execution time of the proposed PIC protocol. Extensive simulations are conducted to compare the proposed PIC protocol with prior works side-by-side. The simulation results demonstrate that PIC significantly outperforms the state-of-the-art protocols in terms of time-efficiency. Auteurs: Xin Xie;Xiulong Liu;Keqiu Li;Bin Xiao;Heng Qi; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 10.-2017, volume: 16, issue:10, pages: 2792 - 2805 Editeur: IEEE Document complet vers site de l'éditeur
» Minimizing Completion Time for Order Scheduling: Formulation and Heuristic Algorithm
 Résumé:In this study, the customer order scheduling problem is investigated to minimize total weighted completion time. A quadratic formulation is proposed to address this problem. This formulation is converted into an equivalent mixed-integer linear programming model by applying the linearization technique and the special structure of the problem. The problem size that can be solved to optimality is then investigated and reported based on the final linearized formulation. Furthermore, a hybrid nested partitions algorithm is developed to solve large-scale problems. Numerical results illustrate the advantages of the proposed model and demonstrate that the proposed algorithm can obtain high-quality solutions within a reasonable computational time. Auteurs: Zhongshun Shi;Longfei Wang;Pai Liu;Leyuan Shi; Apparue dans: IEEE Transactions on Automation Science and Engineering Date publication: 10.-2017, volume: 14, issue:4, pages: 1558 - 1569 Editeur: IEEE Document complet vers site de l'éditeur
» Minimum Storage Regenerating Codes for All Parameters
 Résumé:Regenerating codes for distributed storage have attracted much research interest in the past decade. Such codes trade the bandwidth needed to repair a failed node with the overall amount of data stored in the network. Minimum storage regenerating (MSR) codes are an important class of optimal regenerating codes that minimize (first) the amount of data stored per node and (then) the repair bandwidth. Specifically, an $[n,k,d]$ - $(\alpha )$ MSR code $\mathbb {C}$ over $\smash {\mathbb {F}_{\!q}}$ stores a file ${\mathcal{ F}}$ consisting of $\alpha k$ symbols over $\smash {\mathbb {F}_{\!q}}$ among $n$ nodes, each storing $\alpha$ symbols, in such a way that: 1) the file ${\mathcal{ F}}$ can be recovered by downloading the content of any $k$ of the $n$ nodes and 2) the content of any failed node can be reconstructed by accessing any $d$ of the remaining $n-1$ nodes and downloading $\alpha- /(d{-}k{+}1)$ symbols from each of these nodes. In practice, the file ${\mathcal{ F}}$ is typically available in uncoded form on some $k$ of the $n$ nodes, known as systematic nodes, and the defining node-repair condition above can be relaxed to requiring the optimal repair bandwidth for systematic nodes only. Such codes are called systematic–repair MSR codes. Unfortunately, finite– $\alpha$ constructions of $[n,k,d]$ MSR codes are known only for certain special cases: either low rate, namely $k/n \leqslant 0.5$ , or high repair connectivity, namely $d = n-1$ . Our main result in this paper is a finite– $\alpha$ construction of systematic-repair $[n,k,d]$ MSR codes for all possible values of parameters $n,k,d$ . We also introduce a generalized construction for $[n,k]$ MSR codes to achieve the optimal repair bandwidth for all values of $d$ simultaneously. Auteurs: Sreechakra Goparaju;Arman Fazeli;Alexander Vardy; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6318 - 6328 Editeur: IEEE Document complet vers site de l'éditeur
» Minimum-Cost Crowdsourcing with Coverage Guarantee in Mobile Opportunistic D2D Networks
 Résumé:With the remarkable proliferation of intelligent wireless devices and active mobile users, we have witnessed a rapid increasing trend of mobile crowdsourcing applications. While crowdsourcing does not depend on any specific underlying network, the device-to-device (D2D)-based crowdsourcing is highly desired when the originator of a crowdsourcing task cannot directly reach out to the participants or the conventional approaches for data transportation are costly. The marriage of crowdsourcing and D2D creates new, interesting research problems, mainly due to the unique non-deterministic setting in D2D. In this work, we focus on the problem of how to efficiently distribute a crowdsourcing task and recruit participants based on D2D communications. We formally formulate the minimum-cost crowdsourcing (MCC) problem in D2D networks, which explores a multi-dimensional design space to seek an optimal solution that minimizes the total crowdsourcing cost while satisfying the coverage probability over the field of interest. We introduce an approximation algorithm based on a reduced solution space and formally prove that its cost is bounded by a desired approximation ratio in comparison with the optimal solution. We further propose a lightweight online heuristic that inherits the same design philosophy but implements it in a distributed manner. We prototype the proposed online scheme in Android and carry out experiments in a campus environment, involving 21 Dell Streak tablets carried by students for a period of 15 days. We also extract the algorithm codes from our prototype and perform extensive simulations based on Haggle trace. The results demonstrate the efficiency of the proposed heuristics and reveal empirical insights into the design tradeoffs and practical considerations in D2D-based crowdsourcing. Auteurs: Yanyan Han;Hongyi Wu; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 10.-2017, volume: 16, issue:10, pages: 2806 - 2818 Editeur: IEEE Document complet vers site de l'éditeur
» Mining Top-k Co-Occurrence Patterns across Multiple Streams
 Résumé:The recent Bigdata and IoT era has presented a number of applications that generate objects in a streaming fashion. It is well-known that real-time mining of important patterns from data streams support many domains. In retail markets and social network services, for example, such patterns are itemsets and words that frequently appear in many user-accounts, i.e., co-occurrence patterns. To efficiently monitor co-occurrence patterns, we address the novel problem of mining top-k closed co-occurrence patterns across multiple streams. We employ sliding window setting in this problem, and each pattern is ranked based on count, which is the number of streams that have generated the pattern. Since objects are consecutively generated and deleted, the count of a given pattern is dynamic, which may change the rank of the pattern. This renders a challenge to monitoring the top-k answer in real-time. We propose an index-based algorithm that addresses the challenge and provides the exact answer. Specifically, we propose the CP-Graph, a hybrid index of graph and inverted file structures. The CP-Graph can efficiently compute the count of a given pattern and update the answer while pruning unnecessary patterns. Our experimental study on real datasets demonstrates the efficiency and scalability of our solution. Auteurs: Daichi Amagata;Takahiro Hara; Apparue dans: IEEE Transactions on Knowledge and Data Engineering Date publication: 10.-2017, volume: 29, issue:10, pages: 2249 - 2262 Editeur: IEEE Document complet vers site de l'éditeur
» Mission Critical Analysis and Design of IGBT-Based Power Converters Applied to Mine Hoist Systems
 Résumé:Mine hoist systems play a vital role in gold ore transportation. They are the connection between the underground mine and the beneficiation plant. As a result, any hoist system interruption compromises the production. In this paper, it is proposed a mission critical analysis and design methodology for power converters in order to achieve proper reliability of the hoist drive system. Since the failure of power devices is responsible for a significant portion of the total downtime of power converters, a detailed study of the insulated gate bipolar transistor (IGBT) power modules lifetime is carried out. The three level neutral-point-clamped and Active Neutral Point Clamped (ANPC) IGBT-based topologies are considered for this application. The recently presented Fault-Tolerant (FT)-ANPC converter is proposed as a higher reliability solution leading to longer power modules and drive system lifetimes. All the studies are based on practical operating data from a 900-m deep shaft hoist system operating in a gold mine in southeastern Brazil. Auteurs: Victor de Nazareth Ferreira;Gabriel Alves Mendonça;Anderson Vagner Rocha;Robson Silva Resende;Braz de Jesus Cardoso Filho; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 5096 - 5104 Editeur: IEEE Document complet vers site de l'éditeur
» Mitigating Service Variability in MapReduce Clusters via Task Cloning: A Competitive Analysis
 Résumé:Measurement traces from real-world production environment show that the execution time of tasks within a MapReduce job varies widely due to the variability in machine service capacity. This variability issue makes efficient job scheduling over large-scale MapReduce clusters extremely challenging. To tackle this problem, we adopt the task cloning approach to mitigate the effect of machine variability and design corresponding scheduling algorithms so as to minimize the overall job flowtime in different scenarios. For offline scheduling where all jobs arrive at the same time, we design an $O(1)$ -competitive algorithm, which gives priorities to jobs with small effective workload. We then extend this offline algorithm to yield the so-called Smallest Remaining Effective Workload based $\beta$ -fraction Sharing plus Cloning algorithm (SREW+C($\beta$ )) for the online case. We also show that SREW+C($\beta$ ) is $(1+ 2\beta + \epsilon)$ -speed $O(\frac{1}{\beta \epsilon })$ -competitive with respect to the sum of job flowtime within a cluster. We demonstrate via trace-driven simul- tions that SREW+C( $\beta$ ) can significantly reduce the overall job flowtime by cutting down the elapsed time of small jobs substantially. In particular, SREW+C($\beta$ ) reduces the total job flowtime by 14, 10 and 11 percent respectively when comparing to Mantri, Dolly and Grass. Auteurs: Huanle Xu;Wing Cheong Lau;Zhibo Yang;Gustavo de Veciana;Hanxu Hou; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 10.-2017, volume: 28, issue:10, pages: 2866 - 2880 Editeur: IEEE Document complet vers site de l'éditeur
» Mitigation Method of the Shaft Voltage According to Parasitic Capacitance of the PMSM
 Résumé:This study proposes the shaft voltage mitigation method according to change in parasitic capacitances of a permanent magnet synchronous motor. To consider the shaft voltage reduction in the initial motor design process without any filter, the parasitic capacitances affecting the shaft voltage are calculated using the motor geometry parameters. Then, the shaft voltage is analyzed according to change in parasitic capacitances using the equivalent circuit model and the torque characteristic is also analyzed to effectively mitigate the shaft voltage. As a result, the rotor-to-winding is determined as an appropriate parameter to mitigate the shaft voltage among the parasitic capacitances, because it affects the shaft voltage and does not affect the output torque. Finally, the shaft voltage mitigation method according to variation of rotor-to-winding capacitance is verified by experiment. Auteurs: Jun-kyu Park;Thusitha Randima Wellawatta;Sung-Jin Choi;Jin Hur; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4441 - 4449 Editeur: IEEE Document complet vers site de l'éditeur
» Mixed-Effect Models for the Analysis and Optimization of Sheet-Metal Assembly Processes
 Résumé:Assembly processes can be affected by various parameters, which is revealed by the measured geometrical characteristics (GCs) of the assembled parts deviating from the nominal values. Here, we propose a mixed-effect model (MEM) application for the purposes of analyzing variations in assembly cells, as well as for screening the input variables and characterization. MEMs make it possible to take into account statistical dependencies that originate from repeated measurements on the same assembly. The desirability functions approach was used to describe how to find corrective or control actions based on the fitted MEM. Objectives: To examine the usefulness of the MEM between the positions of the in-going parts as the input controllable variables and the measured GCs as the outputs. Methods: The data from 34 car frontal cross members (each measured three times) were experimentally collected in a laboratory environment by intentionally changing the positions of the in-going parts, assembling the parts, and subsequently measuring their GCs. A single MEM that completely describes the assembly process was fitted between the GCs and the positions of the in-going parts. Results: We present a modeling technique that can be used to establish which measured GCs are influenced by which controllable variables, and how this occurs. The fitted MEM shows evidence that the variability of some GCs changes over time. The natural variation in the system (i.e., unmodeled variations) is about two times larger than the variation between the assembled cross members. We also present two cases that demonstrate how to use the fitted MEM desirability functions to find corrective or control actions. Conclusion: MEMs are very useful tools for analyzing the assembly processes for car-body parts, which are nonlinear processes with multiple inputs and multiple correlated outputs. MEMs can potentially be applied in numerous industrial- processes, since modern manufacturing plants measure all important process variables, which is the sole prerequisite for MEMs applications. Auteurs: Ivan Tomasic;Alf Andersson;Peter Funk; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2194 - 2202 Editeur: IEEE Document complet vers site de l'éditeur
» Mobile Live Video Streaming Optimization via Crowdsourcing Brokerage
 Résumé:Nowadays, people can enjoy a rich real-time sensing cognition of what they are interested in anytime and anywhere by leveraging powerful mobile devices such as smartphones. As a key support for the propagation of these richer live media contents, cellular-based access technologies play a vital role to provide reliable and ubiquitous Internet access to mobile devices. However, these limited wireless network channel conditions vary and fluctuate depending on weather, building shields, congestion, etc., which degrade the quality of live video streaming dramatically. To address this challenge, we propose to use crowdsourcing brokerage in future networks which can improve each mobile user's bandwidth condition and reduce the fluctuation of network condition. Further, to serve mobile users better in this crowdsourcing style, we study the brokerage scheduling problem which aims at maximizing the user's quality of experience satisfaction degree cost effectively. Both offline and online algorithms are proposed to solve this problem. The results of extensive evaluations demonstrate that by leveraging crowdsourcing technique, our solution can cost-effectively guarantee a higher quality view experience. Auteurs: Taotao Wu;Wanchun Dou;Qiang Ni;Shui Yu;Guihai Chen; Apparue dans: IEEE Transactions on Multimedia Date publication: 10.-2017, volume: 19, issue:10, pages: 2267 - 2281 Editeur: IEEE Document complet vers site de l'éditeur
» Model Predictive Control of a Voltage-Source Inverter With Seamless Transition Between Islanded and Grid-Connected Operations
 Résumé:Inverter-based distributed generation (DG) system is becoming an attractive solution for high penetration of renewable energy sources to the main grid. DG system should be able to supply power to the local loads whenever necessary even in case of utility power outage. Thus, the inverters in DG systems are expected to operate in both grid-connected and islanded mode, where they are acting as a current source for the ac grid and a voltage-source for the load, respectively. Transition between modes of operation is nontrivial and can cause deviations in voltage and current, because of mismatch in frequency, phase, and amplitude between the inverter output voltage and the grid voltage. Thus, it is necessary to have seamless transition between grid-connected and islanded mode. This paper presents a new control strategy with seamless transfer characteristics for a grid-connected voltage-source inverter using model predictive control (MPC) framework. The main objectives of the proposed predictive controller are: 1) decoupled power control in grid-connected mode, which enables the proposed power electronics interface to provide ancillary services such as reactive power compensation; 2) load voltage control in islanded mode; and 3) seamless transition between modes of operation through proposed synchronization and phase adjustment algorithm. The proposed controller features simplicity to implement since only one cost function should be minimized for all modes of operation, and hence no ambiguity in the control algorithm that could cause mode transition problems. An autotuning strategy for weight factors in MPC cost function is proposed to simplify the weight factor tuning strategy. The stability analysis of the proposed controller is provided. Simulation and experimental results validate the expected performance and effectiveness of the proposed control strategy. Auteurs: Xiao Li;Haiyu Zhang;Mohammad B. Shadmand;Robert S. Balog; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7906 - 7918 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling and Analysis of Lithium Battery Operations in Spot and Frequency Regulation Service Markets in Australia Electricity Market
 Résumé:Renewable share in the global total energy mix is predicted to grow, and this leads to an increase in the required capacity for frequency regulation. While an electric vehicle (EV) is gaining more popularity, a collection of retired EV battery packs provides an economic option for meeting the additional frequency regulation needs. In this paper, a battery market operation model is proposed to maximize financial return, and a battery operation cost estimator is built to evaluate the potential impacts of market operations on the battery lifespan. Specifically, the model is designed for retired EV lithium batteries under the Australian national electricity market framework. It predicts the automatic-generation-control energy due to the frequency regulation service offers. Battery cycle life cost and battery capacity degradation are considered in the model. It can be used to determine multimarket offers based on the expected profit. Nonetheless, the model can be generalized for other electricity market frameworks and battery types. Auteurs: Qiwei Zhai;Ke Meng;Zhao Yang Dong;Jin Ma; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2576 - 2586 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling and Analysis of Noise Sources for Thin-Film Magnetoelectric Sensors Based on the Delta-E Effect
 Résumé:We present a comprehensive noise model for an electromechanical resonator that is utilized as a magnetic field sensor. The cantilever-type sensor is coated with a magnetostrictive film that exhibits a change in elastic modulus E with a magnetic field and therefore detunes the resonator—the so-called delta-E effect. The noise model contains all relevant noise sources from the operational electronics, the wiring, and the sensor itself. Measurements show good agreement up to a certain excitation voltage, where an additional dominant noise source appears. It is identified as originating from the magnetic film. With the results of the model, the operational parameters of such sensors are discussed. The model predicts that the limit of detection at 10 Hz for the present sensors can be improved to 60 pT/(Hz) $^{1/2}$ if the magnetic noise is eliminated. Auteurs: Phillip Durdaut;Jens Reermann;Sebastian Zabel;Christine Kirchhof;Eckhard Quandt;Franz Faupel;Gerhard Schmidt;Reinhard Knöchel;Michael Höft; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2771 - 2779 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling and Analysis of Non-Orthogonal MBMS Transmission in Heterogeneous Networks
 Résumé:Multimedia broadcast/multicast service (MBMS) transmission, which distributes the media content to multiple users on the same radio resources by using point-to-multipoint communications, is a highly spectrum efficient mechanism for multimedia communications. In this paper, we study the application of power domain non-orthogonal transmission to MBMS enhancements in a $K$ -tier heterogeneous network, in order to satisfy the ever-increasing demands for emerging applications and performance requirements. Then, we present non-orthogonal multi-rate MBMS transmission (NOMRMT) and non-orthogonal multi-service MBMS transmission schemes and investigate their performance by using stochastic geometry. A tractable mode is developed to analyze the performance of asynchronous and synchronous non-orthogonal MBMS transmission. Based on this model, analytical expressions for the signal-to-interference-plus-noise ratio coverage probability, average number of served users, and sum rate are derived. The results demonstrate that non-orthogonal MBMS transmission can achieve better performance than the orthogonal one, while synchronous non-orthogonal MBMS transmission is superior to the asynchronous one. Auteurs: Zhengquan Zhang;Zheng Ma;Ming Xiao;Gang Liu;Pingzhi Fan; Apparue dans: IEEE Journal on Selected Areas in Communications Date publication: 10.-2017, volume: 35, issue:10, pages: 2221 - 2237 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling and Assessment Analysis of Various Compensation Topologies in Bidirectional IWPT System for EV Applications
 Résumé:Electric vehicle (EV) can act as an energy consuming device or a distributed energy resource in the concepts known as vehicle-to-grid (V2G) and grid-to-vehicle (G2V). The bidirectional wireless power interface is a successful choice for this application, since it provides automatic, reliable, and safe operation. Therefore, this paper presents modeling and assessment analysis for the steady-state performance of bidirectional inductive wireless power transfer system (BIWPTS) in EV implementations. The analysis is presented for the three main compensation configurations: LC-series, LC-parallel, and LCL-topology. Moreover, the steady-state equivalent circuit-based mathematical models for all topologies are developed. These models were used to precisely determine the system response during V2G and G2V operations based on Fourier series. The study presents evident criteria to pick among the different BIWPTS structures in the diverse applications. The proposed analyses were verified both in simulation and experiment. The results demonstrate the ability of the proposed models to provide accurate estimation for BIWPTS performance under various operating and control conditions. Also, the evaluation analysis shows that LCL-topology is more appropriate for the bidirectional operation due to the simple design and control requirements, and being less sensitive to the misalignment. Auteurs: Ahmed A. S. Mohamed;Alberto Berzoy;Felipe G. N. de Almeida;Osama Mohammed; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4973 - 4984 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling and Control of Three-Phase Grid-Connected Power Supply With a Small DC-Link Capacitor for Electrolyzers
 Résumé:In this paper, a new feed forward dc-link voltage compensation method is proposed. The target applications are the converters built with diode bridge frontends, small capacitance in the dc-link which feeds a dc/dc converter used for electrolysis. The compensation method can be tuned in a way to minimize the grid side total harmonic distortion (THD) and partial weighted harmonic distortion (PWHD): thus, the converter can comply with the standards with less filtering at the grid side. In order to design the controllers and perform stability analysis, average model has been derived. However, the performance of the proposed control method is a trade-off between the size of the line filter, the value of the line current THD and PWHD, and the amplitude of the load current ripple. The theoretical work has been validated through experiments on a 5 kW dc power supply used for an electrolyzer. In the experiments, the THD of the grid current can be reduced from 30.5% to 29.5% (without filter and including compensation) and 28.5% (with filter and compensation), and the PWHD from 50% to 38.9% by applying the proposed method and also keeping the load current peak-to-peak ripple under 10% of its nominal value. Auteurs: Lajos Török;Laszlo Mathe;Carsten Karup Nielsen;Stig Munk-Nielsen; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4634 - 4643 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling and Mitigation of Static Noise Margin Variation in Subthreshold SRAM Cells
 Résumé:In energy-constrained applications, SRAM systems operating in the subthreshold region are often deployed to reduce power consumption. Subthreshold SRAM designs, however, confront numerous challenges, such as susceptibility to process variation and reduced ON–OFF current ratio. Statistical modeling of the variation in cell stability is critical in SRAM design, especially, for designs operating in the subthreshold region, where the process and temperature variations are the most pronounced. In this paper, statistical models for estimating the static noise margins (SNMs) of SRAM cells are built from the perspective of a shifted voltage transfer characteristic. Read (hold) SNM of a subthreshold 8T cell is analyzed. It is shown that the distribution of a single-sided read SNM is a weighted sum of several normal distributions instead of a regular Gaussian distribution. The proposed statistical model is verified with simulation results in 65-nm technology. Furthermore, to mitigate performance and yield degradation, an adaptive body biasing circuit is developed. It is demonstrated through simulation that, with a negligible area and power overhead, the proposed circuit achieves a 15% improvement in the worst case read SNM. Auteurs: Nan Zheng;Pinaki Mazumder; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2726 - 2736 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling and Offset-Free Model Predictive Control of a Hydraulic Mini Excavator
 Résumé:During the virtual development and experimental testing of advanced construction machinery, automation approaches for automated task execution can prove very valuable. In this paper, modeling and automation approaches for a hydraulic mini excavator are developed. In particular, a physical model for detailed system analysis and a simplified Hammerstein model for controller tuning are developed and validated with measurement data from the mini excavator. For attitude estimation of the excavator, inertial measurement units and extended Kalman filters are used in a sensor fusion framework. The control concept for automation is based on a virtual driver consisting of a state machine for task coordination as well as offset-free model predictive controllers (MPCs) for decentralized and robust tracking control of all motion axes. The constrained MPC optimization problems are solved in real time by means of the accelerated proximal gradient method. Experimental results from the mini excavator prove the developed control approach to be valuable for virtual development and automated testing during the commissioning of hydraulic machinery.Note to Practitioners—In this paper, a hydraulic mini excavator is considered for demonstrating the benefits of automation with regard to the development of advanced mobile machinery. A detailed physical model and a simplified model are introduced for virtual analysis and comissioning of the excavator. This allows for detailed system analysis even at an early development stage. Then, a framework for automated testing of the real prototype is introduced. This concept is based on attitude estimation filters, a state machine, and model predictive controllers and closely resembles the human driver in its behavior, but allows for reproducible testing results and therefore reduces commissioning efforts and development costs. Particular attention is paid to the robustness of the control concept, since the c- upling of the hydraulic axes and digging forces lead to disturbances that need to be compensated. A simple, yet efficient and real-time capable algorithm is provided for numerical optimization. Experimental results show that the developed methods can contribute to the automation of hydraulic machinery, and that the introduced framework can easily be extended in order to automate other types of machinery with simple hydraulics. Auteurs: Frank A. Bender;Simon Göltz;Thomas Bräunl;Oliver Sawodny; Apparue dans: IEEE Transactions on Automation Science and Engineering Date publication: 10.-2017, volume: 14, issue:4, pages: 1682 - 1694 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling and Simulating Multiple Failure Masking Enabled by Local Recovery for Stencil-Based Applications at Extreme Scales
 Résumé:Obtaining multi-process hard failure resilience at the application level is a key challenge that must be overcome before the promise of exascale can be fully realized. Previous work has shown that online global recovery can dramatically reduce the overhead of failures when compared to the more traditional approach of terminating the job and restarting it from the last stored checkpoint. If online recovery is performed in a local manner further scalability is enabled, not only due to the intrinsic lower costs of recovering locally, but also due to derived effects when using some application types. In this paper we model one such effect, namely multiple failure masking, that manifests when running Stencil parallel computations on an environment when failures are recovered locally. First, the delay propagation shape of one or multiple failures recovered locally is modeled to enable several analyses of the probability of different levels of failure masking under certain Stencil application behaviors. Our results indicate that failure masking is an extremely desirable effect at scale which manifestation is more evident and beneficial as the machine size or the failure rate increase. Auteurs: Marc Gamell;Keita Teranishi;Jackson Mayo;Hemanth Kolla;Michael A. Heroux;Jacqueline Chen;Manish Parashar; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 10.-2017, volume: 28, issue:10, pages: 2881 - 2895 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling for Partially Spatially Coherent Vortex Beams
 Résumé:We propose a method for modeling a wide class of partially spatially coherent vortex beams. It is shown that any member of such beams can be represented as an incoherent superposition of fully coherent vortex models weighted by a non-negative weighting function. Applying this method, we introduce a new type of partially coherent vortex beams and study its far-field properties. Auteurs: Zhangrong Mei; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 6 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling of Back-Gate Effects on Gate-Induced Drain Leakage and Gate Currents in UTB SOI MOSFETs
 Résumé:The back-gate bias-dependent gate-induced drain leakage (GIDL) and gate current models of ultrathin body (UTB) silicon-on-insulator (SOI) MOSFETs are proposed. From the experimental data, the GIDL current depends on the back bias due to the electric field change in the channel/drain junction. This effect is modeled using effective gate bias as the threshold voltage shifts. The back-gate bias-dependent gate current is also analyzed and modeled. The voltage across the oxide and available charges for tunneling are the important factors. In accumulation bias condition, the gate leakage is mainly flowing through the overlap region, while in inversion bias condition the current is tunneling from the gate to the channel. Both back bias-dependent GIDL and gate current models are implemented into industry standard compact model Berkeley Short-channel IGFET Model-Independent Multi-Gate for UTB SOI transistors. The model is in good agreement with the experimental data. Auteurs: Yen-Kai Lin;Pragya Kushwaha;Harshit Agarwal;Huan-Lin Chang;Juan Pablo Duarte;Angada B. Sachid;Sourabh Khandelwal;Sayeef Salahuddin;Chenming Hu; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 3986 - 3990 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling of Generic Offshore Vessel in Crane Operations With Focus on Strong Rigid Body Connections
 Résumé:Both marine surface vehicles and underwater vehicles are often equipped with cranes, robotic manipulators, or similar equipment. Much attention is given to modeling of both the dynamics of marine vehicles and the dynamics of manipulators, cranes, and other equipment. However, less attention is given to the interconnected behavior of the vehicle and equipment, even though such equipment may have a considerable impact on the vehicle dynamic behavior, and therefore risk, or conversely, the vehicle may have a considerable impact on the equipment dynamic behavior. With main focus on ships equipped with cranes, this paper presents a framework for modeling the interconnected dynamics of rigid body systems, based on Lagrangian dynamics. The resulting equations of motion are implemented as a bond graph template to which any subsystem of interest, such as actuators, hydrodynamics, and controllers, may be interfaced. An example on how this framework can be used to develop a high-fidelity simulator of an offshore installation vessel with a heavy duty crane is presented. This work represents the first bond graph implementation of crane and vessel dynamics where the interconnections are modeled according to true physical rigid body principles without nonphysical limitations such as diagonal mass-inertia matrix. Auteurs: Børge Rokseth;Stian Skjong;Eilif Pedersen; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 846 - 868 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling of Short-Circuit-Related Thermal Stress in Aged IGBT Modules
 Résumé:In this paper, the thermal stress on bond wires of aged insulated gate bipolar transistor modules under short-circuit conditions has been studied with respect to different solder delamination levels. To ensure repeatable test conditions, ad-hoc direct bond copper samples with delaminated solder layers have been purposely fabricated. The temperature distribution produced by such abnormal conditions has been modeled first by means of finite-element method simulations and then experimentally validated by means of a nondestructive testing technique, including an ultrafast infrared camera. Results demonstrate a significant imbalance in the surface temperature distribution, which confirms the hypothesis that short-circuit events produce significantly uneven stresses on bond wires. Auteurs: Amir Sajjad Bahman;Francesco Iannuzzo;Christian Uhrenfeldt;Frede Blaabjerg;Stig Munk-Nielsen; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4788 - 4795 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling of Space Charge Effects in Intense Electron Beams: Kinetic Equation Method Versus PIC Method
 Résumé:In this paper, we present the simulation results for the most important 1-D problems of current flow in planar vacuum diodes. For the first time, classical problems of vacuum electronics have been solved using the basic principles of nonequilibrium physical kinetics. This approach is based on the accurate numerical solution of the Vlasov–Poisson equation system to find the electron distribution function. We have obtained time-dependent numerical solutions that satisfactorily agree with theoretical approximations and with particle-in-cell simulations as well. Auteurs: Vasily Yu. Kozhevnikov;Andrey V. Kozyrev;Natalia S. Semeniuk; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2762 - 2766 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling of Viscoelastic Electromechanical Behavior in a Soft Dielectric Elastomer Actuator
 Résumé:Soft dielectric elastomer actuators (DEAs) exhibit interesting muscle-like behavior for the development of soft robots. However, it is challenging to model these soft actuators due to their material nonlinearity, nonlinear electromechanical coupling, and time-dependent viscoelastic behavior. Most recent studies on DEAs focus on issues of mechanics, physics, and material science, while much less importance is given to quantitative characterization of DEAs. In this paper, we present a detailed experimental investigation probing the voltage-induced electromechanical response of a soft DEA that is subjected to cyclic loading and propose a general constitutive modeling approach to characterize the time-dependent response, based on the principles of nonequilibrium thermodynamics. In this paper, some of the key observations are found as follows: 1) Creep exhibits the drift phenomenon, and is dominant during the first three cycles. The creep decreases over time and becomes less dominant after the first few cycles; 2) a significant amount of hysteresis is observed during all cycles and it becomes repeatable after the first few cycles; 3) the peak of the displacement is shifted from the peak of the voltage signal and occurs after it. To account for these viscoelastic phenomena, a constitutive model is developed by employing several dissipative nonequilibrium mechanisms. The quantitative comparisons of the experimental and simulation results demonstrate the effectiveness of the developed model. This modeling approach can be useful for control of a viscoelastic DEA and paves the way to emerging applications of soft robots. Auteurs: Guo-Ying Gu;Ujjaval Gupta;Jian Zhu;Li-Min Zhu;Xiangyang Zhu; Apparue dans: IEEE Transactions on Robotics Date publication: 10.-2017, volume: 33, issue:5, pages: 1263 - 1271 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling of Wave Propagation in Isotropic Cold Plasma Using Iterative WLP-FDTD Algorithm
 Résumé:In this letter, an efficient implementation of the iterative unconditionally stable finite-difference time domain (FDTD) based on weighted Laguerre polynomials (WLPs) algorithm is presented for isotropic cold plasma. The iterative scheme is employed to reduce the splitting error in WLP-FDTD with factorization-splitting procedure. Meanwhile, a stretched-coordinate perfectly matched layer with a complex-frequency-shifted factor is used as the absorbing boundary condition. Numerical example demonstrates the accuracy and efficiency of the proposed algorithm. Auteurs: Yun Fang;Xiao-Li Xi;Jia-Huan Zheng;Jiang-Fan Liu;Yu-Rong Pu;Jin-Sheng Zhang; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 861 - 863 Editeur: IEEE Document complet vers site de l'éditeur
» Modeling the Temporal Variability of Thermal Emissions From Row-Planted Scenes Using a Radiosity and Energy Budget Method
 Résumé:Land surface temperature (LST) is often needed for using remotely sensed data to study the surface energy budget and hydrological cycle. However, LST is challenging to measure and simulate because of its high sensitivity to atmospheric instability and solar angle, particularly over large-scale heterogeneous scenes. We propose a model that combines radiosity theory and an energy budget method for surface temperatures; we also explore the anisotropic behavior of row-planted crop emissions. The surface thermodynamic equilibrium state is fulfilled via the interaction between the 3-D radiative transfer calculations of the thermal-region radiosity-graphics combined model and the energy balance equation. Despite its shortcomings, such as the time-consuming calculations, the proposed model is feasible according to the results of an intercomparison and validation analysis. The intercomparison shows that the model exhibits similar performance, in terms of surface temperature calculations, to that of the soil-canopy observation, photochemistry and energy balance model (root-mean-square differences) of 0.59 °C and 1.77 °C for the leaf and soil components, respectively. Excellent agreement with the observed directional variation over summer maize canopies is also obtained, with $\text{R}^{2}$ values exceeding 0.6 and a mean RMSE of 0.32 °C. Thus, we recommend the new combined model as an option for explaining directional anisotropy due to its potential application to 3-D scenes. Auteurs: Zunjian Bian;Yongming Du;Hua Li;Biao Cao;Huaguo Huang;Qing Xiao;Qinhuo Liu; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 6010 - 6026 Editeur: IEEE Document complet vers site de l'éditeur
» Models and Information Rates for Multiuser Optical Fiber Channels With Nonlinearity and Dispersion
 Résumé:Two discrete-time interference channel models are developed for information transmission over a single span of optical fiber using wavelength-division multiplexing (WDM) and lumped amplification. The models are derived from the nonlinear Schrödinger equation by including the nonlinear phenomena of self-phase modulation (SPM) and cross-phase modulation (XPM), but ignoring four-wave mixing, polarization effects and group velocity dispersion (GVD) within WDM bands. The first model also ignores GVD across WDM bands, referred to as group velocity mismatch (GVM). For the case of two users, a new technique called interference focusing is proposed where each carrier achieves the capacity pre-log 1, thereby doubling the pre-log of 1/2 achieved by using conventional methods. For three users, interference focusing is also useful under certain conditions. The second model captures GVM and the effect of filtering at the receivers in addition to SPM and XPM. In a 3-user system, it is shown that all users can achieve the maximum pre-log factor 1 simultaneously by using interference focusing, a time-limited pulse and a bank of filters at the receivers. Auteurs: Hassan Ghozlan;Gerhard Kramer; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6440 - 6456 Editeur: IEEE Document complet vers site de l'éditeur
» Modification of High-Voltage Pulse Waveform by the Spiral and Core-Transformer Ferrite-Filled Lines
 Résumé:The testing results of high-voltage transformer and spiral ferrite-filled lines are presented. The devices convert the envelopes of a bell-shape incident nanosecond pulses with amplitude of about −150 kV. The spiral lines sharpen the front to hundreds of picoseconds, shorten the pulse duration or form an extended continuous pedestal-shape prepulse. The transforming line sharpened a pulse tailing edge from 2 to 1 ns and changed its polarity. Auteurs: Marat R. Ulmaskulov;Sergei A. Shunailov;Konstantin A. Sharypov;Michael I. Yalandin;Valery G. Shpak; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2707 - 2714 Editeur: IEEE Document complet vers site de l'éditeur
» Modified pq-Theory-Based Control of Solar-PV-Integrated UPQC-S
 Résumé:This paper proposes a modified pq-theory-based control of a solar photovoltaic (PV)-array-integrated unified power quality conditioner (PV-UPQC-S). The system incorporates clean energy generation along with power quality improvement, thus increasing functionality of the system. The fundamental-frequency positive-sequence components of voltages at the point of common coupling (PCC) are extracted using the generalized cascaded delay signal cancellation technique, which are then used in pq-theory-based control to estimate reference signals for the PV-UPQC-S. This modification in pq theory enables its application for PV-UPQC-S control under conditions of distorted PCC voltages. The series voltage-source converter (VSC) of the PV-UPQC-S operates such that it shares a part of the reactive power of the load even under nominal grid conditions. This increases the utilization of the series VSC while reducing the rating of shunt VSC. The PV array is integrated at the dc bus of the UPQC and provides a part of active load power, thus reducing demand on the supply system. The dynamic performance of the modified pq-theory-based PV-UPQC-S is verified by simulating the system in MATLAB-Simulink with a combination of linear and nonlinear loads. The steady-state and dynamic performances of the system are then experimentally validated through extensive testing on a scaled-down laboratory prototype. Auteurs: Sachin Devassy;Bhim Singh; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 5031 - 5040 Editeur: IEEE Document complet vers site de l'éditeur
» Modified Entropy-Based Fully Polarimetric Target Classification Method for Ground Penetrating Radars (GPR)
 Résumé:Polarimetric scattering characteristics are useful for classifying different radar targets. In particular, the entropy-based H-α classification method has been widely used in remote sensing for classifying land features with different polarimetric scattering properties. However, this method has not been widely adopted in ground penetrating radars (GPR) applications due to the lack of commercial fully polarimetric GPR systems. This paper will demonstrate that the conventional nine-zone H-α classification chart adopted in remote sensing needs to be modified in order to be effective in classifying GPR targets due to the common presence of noise and clutter. The effects of white noise and clutter on H-α features derived from the fully polarimetric scattering data are discussed. This study led to the development of a new four-zone H-α classification chart. The application and effectiveness of classifying linearly polarized and nonpolarized targets using this new chart will be demonstrated via outdoor measurement examples. Auteurs: Yue Yu;Chi-Chih Chen;Xuan Feng;Cai Liu; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4304 - 4312 Editeur: IEEE Document complet vers site de l'éditeur
» Modulated Predictive Control for Indirect Matrix Converter
 Résumé:Finite state model predictive control (MPC) has been recently applied to several converter topologies, as it can provide many advantages over other MPC techniques. The advantages of MPC include fast dynamics, multitarget control capability, and relatively easy implementation on digital control platforms. However, its inherent variable switching frequency and lower steady-state waveform quality with respect to standard control, which includes an appropriate modulation technique, represent a limitation to its applicability. Modulated model predictive control (M2 PC) combines all the advantages of MPC with the fixed switching frequency characteristic of pulse-width modulation algorithms. The work presented in this paper focuses on the indirect matrix converter (IMC), where the tight coupling between rectifier stage and inverter stage has to be taken into account in the M2PC design. This paper proposes an M2PC solution, suitable for IMC, with a switching pattern that emulates the desired waveform quality features of space vector modulation for matrix converters. The switching sequences of the rectifier stage and inverter stage are rearranged in order to always achieve zero-current switching on the rectifier stage, thus simplifying the current commutation strategy. Auteurs: Luca Tarisciotti;Jiaxing Lei;Andrea Formentini;Andrew Trentin;Pericle Zanchetta;Patrick Wheeler;Marco Rivera; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4644 - 4654 Editeur: IEEE Document complet vers site de l'éditeur
» Monolayer ZnS as a Promising Candidate for NH3 Sensor: A First-Principle Study
 Résumé:In this paper, the interaction of atmospheric gas molecules (NH3, NO2, SO2, CO, CO2, CH4, O2, and NO) with monolayer graphene-like hexagonal ZnS (g-ZnS) is studied with the first-principle calculations to explore its potential application as gas sensor. Among all the gas molecules, NH3, and SO2, NO2 act as a strong donor and acceptor with apparent charge transfer of 0.200, −0.121, and −0.115 e. We further calculated the current-voltage (I−V) relation using the nonequilibrium Green's function formalism. It can be indicated from the results that a mark change of the I−V relation before and after the adsorption of NH3, which makes monolayer g-ZnS a prospective gas sensor for NH3. In addition, under the mechanical strain the adsorption is substantially enhanced with significant impact on the properties of adsorbates and g-ZnS layer, especially for the NH3, NO2, and NO-monolayer g-ZnS configurations. The results presented herein demonstrate that monolayer g-ZnS can be the potential gas sensor of NH3 with high sensitivity and selectivity. Auteurs: Yixin Xu;Ruishen Meng;Daxi Xiong;Xiang Sun;Shaogang Wang;Jing Xiao;Xianping Chen; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6515 - 6521 Editeur: IEEE Document complet vers site de l'éditeur
» Monostatic Co-Polarized Full-Duplex Antenna With Left- or Right-Hand Circular Polarization
 Résumé:A monostatic dual-polarized simultaneous transmit and receive (STAR) antenna system with high isolation is introduced. A beamforming network (BFN) producing 0°, ±90°, ±180°, and ±270° phase progression is used to feed TX and RX ports of four dual-polarized antenna elements arranged in a sequential rotation array (SRA). Due to the phase progression and geometrical symmetry of SRA, the coupling from TX to RX ports is canceled at the RX port of the BFN; therefore, infinite system isolation is theoretically obtained. Full-wave simulations are used to verify the theory and study effects of element spacing and BFN imbalances. An additional cancelation layer is designed and used to compensate for the imbalances by the BFN and nearby scatterers. The proposed STAR antenna system is prototyped and tested in the 2.4–2.5 GHz industrial, scientific, and medical band where the measured isolation and return loss are above 47 and 22 dB, respectively. A dual circularly polarized antenna performance with realized gains above 7 dBic, broadside axial ratio <1.6 dB, and symmetric beams is demonstrated. An ability of the proposed monostatic STAR antenna system to achieve wideband operation is also demonstrated with a quad-ridge horn as an element. Auteurs: Jaegeun Ha;Mohamed A. Elmansouri;Prathap Valale Prasannakumar;Dejan S. Filipovic; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5103 - 5111 Editeur: IEEE Document complet vers site de l'éditeur
» Multi-Agent Second Order Average Consensus With Prescribed Transient Behavior
 Résumé:The problem of consensus reaching with prescribed transient behavior for a group of double-integrator agents is addressed. The information exchange of the multi-agent system is described by a static communication network. We initially set time-dependent constraints on the transient response of the relative positions between neighboring agents and we propose a distributed control law consisting of a proportional term of the transformed error and an additional damping term based on absolute velocities measurements. We also design an agreement protocol that can additionally achieve prescribed performance for a combined error of positions and velocities. Under a sufficient condition for the damping gains, the proposed nonlinear time-dependent distributed controllers guarantee that the predefined constraints are not violated and that consensus is achieved with a convergence rate independent of the underlying communication graph. Furthermore, connectivity maintenance can be ensured by appropriately designing the performance bounds. Theoretical results are supported by simulations. Auteurs: Luca Macellari;Yiannis Karayiannidis;Dimos V. Dimarogonas; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5282 - 5288 Editeur: IEEE Document complet vers site de l'éditeur

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