###### 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: 4
» Concise Planning and Filtering: Hardness and Algorithms
 Résumé:Motivated by circumstances with severe computational resource limits (e.g., settings with strong constraints on memory or communication), this paper addresses the problem of concisely representing and processing information for estimation and planning tasks. In this paper, conciseness is a measure of explicit representational complexity: for filtering, we are concerned with maintaining as little state as possible to perform a given task; for the planning case, we wish to generate the plan graph (or policy graph) with the fewest vertices that is correct and also complete. We present hardness results showing that both filtering and planning are NP-hard to perform in an optimally concise way, and that the related decision problems are NP-complete. We also describe algorithms for filter reduction and concise planning, for which these hardness results justify the potentially suboptimal output. The filter-reduction algorithm accepts as input an arbitrary combinatorial filter, expressed as a transition graph, and outputs an equivalent filter that uses fewer I-states to complete the same filtering task. The planning algorithm, using the filter-reduction algorithm as a subroutine, generates concise plans for planning problems that may involve both nondeterminism and partial observability. Both algorithms are governed by parameters that encode tradeoffs between computational efficiency and solution quality. We describe implementation of both algorithms and present a series of experiments evaluating their effectiveness. Auteurs: Jason M. O’Kane;Dylan A. Shell; Apparue dans: IEEE Transactions on Automation Science and Engineering Date publication: 10.-2017, volume: 14, issue:4, pages: 1666 - 1681 Editeur: IEEE Document complet vers site de l'éditeur
» Concurrent Control of Mobility and Communication in Multirobot Systems
 Résumé:We develop a hybrid system architecture that enables a team of mobile robots to complete a task in a complex environment by self-organizing into a multihop ad hoc network and solving the concurrent communication and mobility problem. The proposed system consists of a two-layer feedback loop. An outer loop performs infrequent global coordination and a local inner loop determines motion and communication variables. This system provides the lightweight coordination and responsiveness of decentralized systems while avoiding local minima. This allows a team to complete a task in complex environments while maintaining desired end-to-end data rates. The behavior of the system is evaluated in experiments that demonstrate: 1) successful task completion in complex environments; 2) achievement of equal or greater end-to-end data rates as compared to a centralized system; and 3) robustness to unexpected events such as motion restriction. Auteurs: James Stephan;Jonathan Fink;Vijay Kumar;Alejandro Ribeiro; Apparue dans: IEEE Transactions on Robotics Date publication: 10.-2017, volume: 33, issue:5, pages: 1248 - 1254 Editeur: IEEE Document complet vers site de l'éditeur
» Condition and Strategy Analysis for Assembly Based on Attractive Region in Environment
 Résumé:Automatic assembly with high precision is an essential step in robotic manipulation. It is still a difficult problem due to various complicated requirements, such as less contact force, irregular shapes of the parts, sensing information understanding in complex environment, etc. In the previous work, the concept of attractive region in environment (ARIE) was proposed, which helps to achieve high-precision manipulation with low-precision systems by using the constraints formed by the environment. In this paper, the general relation between the physical space and the configuration space for the robotic assembly system will be analyzed, the strategies of using ARIE to achieve high-precision peg-hole assembly will be provided, and furthermore, practical examples for industrial applications will be given, which further illustrates the usefulness of the concept. Auteurs: Rui Li;Hong Qiao; Apparue dans: IEEE/ASME Transactions on Mechatronics Date publication: 10.-2017, volume: 22, issue:5, pages: 2218 - 2228 Editeur: IEEE Document complet vers site de l'éditeur
» Conditions for Almost Global Attractivity of a Synchronous Generator Connected to an Infinite Bus
 Résumé:Conditions for existence and global attractivity of the equilibria of a realistic model of a synchronous generator with constant field current connected to an infinite bus are derived. First, necessary and sufficient conditions for existence and uniqueness of equilibrium points are provided. Then, sufficient conditions for local asymptotic stability and almost global attractivity of one of these equilibria are given. The analysis is carried out by employing a new Lyapunov-like function to establish convergence of bounded trajectories, while the latter is proven using the powerful theoretical framework of cell structures pioneered by Leonov and Noldus. The efficiency of the derived sufficient conditions is illustrated via extensive numerical experiments based on two benchmark examples taken from the literature. Auteurs: Nikita Barabanov;Johannes Schiffer;Romeo Ortega;Denis Efimov; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 4905 - 4916 Editeur: IEEE Document complet vers site de l'éditeur
» Conductor Surface Conditions Effects on the Ion-Flow Field of Long-Term Operating Conductors of the HVDC Transmission Line
 Résumé:The influence of conductor surface conditions of new and aged conductors on ground-level resultant electric field and ion current density is analyzed in this paper. The surface roughness and morphology of conductors are measured and analyzed by 3-D phase shift Micro-Xam (MicroXAM-3D) and scanning electron microscopy. Calculations are made using the upstream finite-element-finite difference method for the corona cage model to obtain the influence of surface conditions on the ion-flow field, consequently, changing the resulting electric field and ion current density. An indoor corona cage platform is build up to check the impact of surface conditions on the ground-level resultant electric field and ion current density in the laboratory. Considering the aging characteristics of the conductor surface, a typical ±800 kV ultra-high voltage direct current transmission line is analyzed. The calculated results show that compared with the new conductor, the electric field and ion current density of the long-term operation conductors increase very significantly. Auteurs: Yong Yi;Chuyan Zhang;Liming Wang;Zhengying Chen; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2171 - 2178 Editeur: IEEE Document complet vers site de l'éditeur
» Conformational Space Sampling Method Using Multi-Subpopulation Differential Evolution for De novo Protein Structure Prediction
 Résumé:Protein structure prediction can be considered as a multimodal optimization problem for sampling the protein conformational space associated with an extremely complex energy landscape. To address this problem, a conformational space sampling method using multi-subpopulation differential evolution, MDE, is proposed. MDE first devotes to generate given numbers of concerned modal under the ultrafast shape recognition-based modal identification protocol, which regards each individual as one modal at beginning. Then, differential evolution is used for keeping the preserved modal survival in the evolution process. Meanwhile, a local descent direction used to sample along with is constructed based on the abstract convex underestimate technique for modal enhancement, which could enhance the ability of sampling in the region with lower energy. Through the sampling process of evolution, several certain clusters contain a series of conformations in proportion to the energy score will be obtained. Representative conformations in the generated clusters can be directly picked out as decoy conformations for further refinement with no extra clustering operation needs. A total of 20 target proteins are tested, in which ten target proteins are tested for comparison with Rosetta and three evolutionary algorithms, and ten easy/hard target proteins in CASP 11 are tested for further verifying the effectiveness of MDE. Test results show strong sampling ability that MDE holds, and near-native conformations can be effectively obtained. Auteurs: Xiao-Hu Hao;Gui-Jun Zhang;Xiao-Gen Zhou; Apparue dans: IEEE Transactions on NanoBioscience Date publication: 10.-2017, volume: 16, issue:7, pages: 618 - 633 Editeur: IEEE Document complet vers site de l'éditeur
» Congestion Control for Background Data Transfers With Minimal Delay Impact
 Résumé:Congestion control protocols for background data are commonly conceived and designed to emulate low priority traffic, which yields to transmission control protocol (TCP) flows. In the presence of even a few very long TCP flows, this behavior can cause bandwidth starvation, and hence, the accumulation of large numbers of background data flows for prolonged periods of time, which may ultimately have an adverse effect on the download delays of delay-sensitive TCP flows. In this paper, we look at the fundamental problem of designing congestion control protocols for background traffic with the minimum impact on short TCP flows while achieving a certain desired average throughput over time. The corresponding optimal policy under various assumptions on the available information is obtained analytically. We give tight bounds of the distance between TCP-based background transfer protocols and the optimal policy, and identify the range of system parameters for which more sophisticated congestion control makes a noticeable difference. Based on these results, we propose an access control algorithm for systems where control on aggregates of background flows can be exercised, as in file servers. Simulations of simple network topologies suggest that this type of access control performs better than protocols emulating low priority over a wide range of parameters. Auteurs: Costas A. Courcoubetis;Antonis Dimakis;Michalis Kanakakis; Apparue dans: IEEE/ACM Transactions on Networking Date publication: 10.-2017, volume: 25, issue:5, pages: 2743 - 2758 Editeur: IEEE Document complet vers site de l'éditeur
» Congestion Control for Web Real-Time Communication
 Résumé:Applications requiring real-time communication (RTC) between Internet peers are ever increasing. RTC requires not only congestion control but also minimization of queuing delays to provide interactivity. It is known that the well-established transmission control protocol congestion control is not suitable for RTC due to its retransmissions and in-order delivery mechanisms, which induce significant latency. In this paper, we propose a novel congestion control algorithm for RTC, which is based on the main idea of estimating—using a Kalman Filter—the end-to-end one-way delay variation which is experienced by packets traveling from a sender to a destination. This estimate is compared with a dynamic threshold and drives the dynamics of a controller located at the receiver, which aims at maintaining queuing delays low, while a loss-based controller located at the sender acts when losses are detected. The proposed congestion control algorithm has been adopted by Google Chrome. Extensive experimental evaluations have shown that the algorithm contains queuing delays while providing intra and inter protocol fairness along with full link utilization. Auteurs: Gaetano Carlucci;Luca De Cicco;Stefan Holmer;Saverio Mascolo; Apparue dans: IEEE/ACM Transactions on Networking Date publication: 10.-2017, volume: 25, issue:5, pages: 2629 - 2642 Editeur: IEEE Document complet vers site de l'éditeur
» Consensus With Output Saturations
 Résumé:This paper considers a standard consensus algorithm under output saturations. In this case, the global consensus cannot be realized due to the existence of stable equilibrium points that do not belong to the consensus manifold. Therefore, this paper investigates necessary and sufficient initial conditions for the achievement of consensus that characterize an exact domain of attraction. Specifically, this paper considers single-integrator agents with both fixed and time-varying undirected graphs. Then, we show that the consensus will be achieved if and only if the average of the initial states is within the minimum saturation level. Auteurs: Young-Hun Lim;Hyo-Sung Ahn; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5388 - 5395 Editeur: IEEE Document complet vers site de l'éditeur
» Considering Backhaul [Book\Software Reviews]
 Résumé:This book offers a comprehensive guide to the subject of microwave backhaul. Design information on this subject is sparse, and it is not easy to collect and interpret. This fact was the driving force behind the creation of this book, which focuses on the electronics of backhaul and describes in detail all the subsystems responsible for transforming the information signal that comes from baseband processing into an electromagnetic wave traveling through the air. Electronics for Microwave Backhaul presents an overview of the evolution of the electronics for microwave radios, from their initial development to present implementations and future trends. The authors have stayed abreast of current real-world industry products and present many real-world solutions to the design issues. Auteurs: James Chu; Apparue dans: IEEE Microwave Magazine Date publication: 10.-2017, volume: 18, issue:6, pages: 125 - 126 Editeur: IEEE Document complet vers site de l'éditeur
» Constrained Dynamic Systems: Generalized Modeling and State Estimation
 Résumé:Due to physical laws or mathematical properties the states of some dynamic systems satisfy certain constraints, and taking advantage of such constraints generally will produce more accurate system models. This paper is concerned with dynamic modeling and state estimation of equality constrained systems. First, an effective framework for constrained dynamic modeling is proposed by which equality constraints and an original dynamics are optimally fused. In particular, modeling of linear and quadratic equality constrained dynamic systems is systematically investigated. Meanwhile, the effects of the original dynamics on the constructed dynamic model are analyzed. Next, properties of the constrained state estimation are presented, and in particular, the constrained minimum mean square error (CMMSE) estimator is proposed and its differences from the conventional constrained estimators are illustrated. Finally, the proposed modeling is assessed on benchmark scenarios of road-confined vehicle tracking. Simulation results demonstrate that the proposed CMMSE estimator outperforms the conventional constrained ones. Auteurs: Linfeng Xu;X. Rong Li;Yan Liang;Zhansheng Duan; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2594 - 2609 Editeur: IEEE Document complet vers site de l'éditeur
» Constructions of Binary Sequence Pairs of Period $3p$ With Optimal Three-Level Correlation
 Résumé:In this letter, we present a new generalized cyclotomic method over $Z_{3p}$ based on the Chinese remainder theorem and the cyclotomic classes of order 2. Two new families of binary sequence pairs of period $N=3p$ with optimal three-level correlation values are constructed by utilizing these new generalized cyclotomic classes, where $p>3$ is an odd prime. All the constructed binary sequence pairs have optimal correlation values {−3, 1} or {−1, 3}. Auteurs: Xiumin Shen;Yanguo Jia;Xiaofei Song; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2150 - 2153 Editeur: IEEE Document complet vers site de l'éditeur
» Contact Force Monitoring and Its Application in Vacuum Circuit Breakers
 Résumé:Condition monitoring of circuit-breaker (CB) operating mechanisms is one the most important aspects of predictive maintenance. This paper proposes a contact force monitoring scheme for 10 ~ 35-kV vacuum CB. With specially designed force sensors and a signal-processing method, we can accurately find the instants of contact touch and separation. With the indirectly measured contact touch-and-separation instants, we can measure the opening speed, closing speed, and open gap over the travel of each phase. The accuracy of our online monitoring scheme is compared with the conventional offline methods that can directly obtain the instants of contact touch and separation by measuring the connectivity of the contacts. The results show that the accuracy of the scheme proposed in this paper is satisfactory and it can meet the engineering requirements of online condition monitoring of CBs. By introducing a set of new force sensors, some additional information that is useful for overall condition assessment of CB operating mechanism can also be extracted; this will help us to find new ways to improve our CB condition monitoring systems. Auteurs: Jianzhong Tang;Shisong Lu;Jingwei Xie;Zhengmin Cheng; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2154 - 2161 Editeur: IEEE Document complet vers site de l'éditeur
» Contactless Current Measurement for Enclosed Multiconductor Systems Based on Sensor Array
 Résumé:How to measure ac currents in a bundle of inaccessible, enclosed conductors has been a challenging problem but with many potential applications. This paper presents a method to solve the problem using an array of magnetic field sensors. The proposed method consists of two novel ideas. The first idea is to use an off-site calibration method to establish sensor parameters including sensing position and angle, which provides more accurate sensor parameter estimation than their nominal values. The second idea is to “measure” (i.e., calculate) conductor currents and positions based on the sensed magnetic fields and preestablished sensor parameters. This process is simplified since the sensor information is obtained by the first idea. Both calibration and measurement tasks are formulated as nonlinear least square problems and solved efficiently. The proposed method is demonstrated for the cases involving ideal three-conductor system and practical residential service cable enclosed in a plastic conduit. The method has the potential for contactless current measurement of Romex cables and overhead distribution lines. Auteurs: Guangchao Geng;Juncheng Wang;Kun-Long Chen;Wilsun Xu; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2627 - 2637 Editeur: IEEE Document complet vers site de l'éditeur
» Content Placement for Wireless Cooperative Caching Helpers: A Tradeoff Between Cooperative Gain and Content Diversity Gain
 Résumé:Depending on what and how caching helpers cache content in their finite storage, the caching helpers can offer either a content diversity gain by serving diverse content or a cooperative gain by jointly transmitting the same content. This paper identifies a tradeoff between the content diversity gain and the cooperative gain according to content placements and proposes a probabilistic content placement to optimally balance the tradeoff. Using stochastic geometry, we quantify this tradeoff by deriving the cache hit rate and the rate coverage probability. To efficiently control the tradeoff, we determine the near-optimal caching probabilities that maximize the average content delivery success probability with the cooperative caching helpers. Our analysis and numerical results reveal that our proposed content placement outperforms the conventional caching schemes, such as caching with uniform probabilities, caching the most popular contents, and caching the content maximizing the cache hit, in terms of the average content delivery success probability. Auteurs: Seong Ho Chae;Tony Q. S. Quek;Wan Choi; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6795 - 6807 Editeur: IEEE Document complet vers site de l'éditeur
» Context-Aware Architecture for Probabilistic Voting-based Filtering Scheme in Sensor Networks
 Résumé:Wireless sensor networks are widely deployed and implicitly characterized by stringent energy and computation constraints. Sensor nodes are vulnerable to false positive and false negative attacks that inject false data through compromised nodes. Such attacks cause false alarms with energy drain and information loss. Although several en-route filtering schemes have been designed to detect the attacks, they focus on saving energy through early filtering or continuous delivery of data in accordance with verification records; they cannot exclude compromised nodes. In this paper, we propose a scheme that effectively identifies the compromised nodes and copes with new attacks using a context-aware architecture. In addition, the proposed scheme improves the security strength and energy efficiency of the network. Simulation results validate that the proposed scheme provides energy savings of up to 45 percent and allows fewer attack successes than the existing scheme. Auteurs: Su Man Nam;Tae Ho Cho; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 10.-2017, volume: 16, issue:10, pages: 2751 - 2763 Editeur: IEEE Document complet vers site de l'éditeur
» Continuous and Singular Micromagnetic Configurations
 Résumé:Up to the present time [1965], only magnetic configurations that are continuous in the micromagnetic sense have been described in the literature. The consequences of this continuity restriction on possible types of magnetization reversal processes have received no attention. These consequences are discussed here. It is also shown that micromagnetic discontinuities are allowed theoretically. In particular, a micromagnetically singular point may exist that is the zero-dimensional analog of the two-dimensional wall and the one-dimensional Bloch or Néel line of magnetic domain theory. Auteurs: Ernst Feldtkeller; 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
» Control and Emulation of Small Wind Turbines Using Torque Estimators
 Résumé:Soft-stall control of small wind turbines is a method to protect the generation system and/or load from excessive wind speeds and wind gusts without discontinuing power generation. Soft-stall can be activated due to an excess of the power and/or torque/current. This paper proposes a method to improve the existing soft-stall methods for over torque/current protection using a turbine torque estimator. In addition, this paper also proposes two methods to emulate the wind turbine inertia without communications between the load drive (wind turbine emulator) and the generation system controller. This will allow the evaluation of the proposed methods in working conditions. Auteurs: Juan M. Guerrero;Carlos Lumbreras;David Díaz Reigosa;Pablo Garcia;Fernando Briz; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4863 - 4876 Editeur: IEEE Document complet vers site de l'éditeur
» Control Design for Disturbance Rejection in the Presence of Uncertain Delays
 Résumé:This paper is concerned with control of processes with uncertain delays for disturbance rejection. The effect of the uncertain delays on the stability is studied. First, the method to compute the maximum uncertain delay that a given controller can tolerate is described. Second, in the case of PI/PID controller, all of the admissible controller parameters stabilizing a system with uncertain but bounded delays are determined. Meanwhile, we propose a simple method to construct the parameter space satisfying a given robustness index for the nominal model. In the admissible regions satisfying various objectives, the global optimum controller is achieved for disturbance rejection in the presence of uncertain delay. As a result, the MIGO ( -constrained Integral Gain Optimization) method is revisited in the case of uncertain delay, and the rule of selecting the value of maximum sensitivity function is proposed in terms of the bound on the uncertain delay. Two simulation examples and an experiment are given to demonstrate the effectiveness and advantage of the proposed method. Auteurs: Qibing Jin;Qie Liu;Biao Huang; Apparue dans: IEEE Transactions on Automation Science and Engineering Date publication: 10.-2017, volume: 14, issue:4, pages: 1570 - 1581 Editeur: IEEE Document complet vers site de l'éditeur
» Control Method of Double Inverter Fed Wound Machine for Minimizing Copper Loss in Maximized Operating Area
 Résumé:A double inverter fed wound machine (DFWM) needs two inverters on the rotor as well as the stator side. This scheme gives more freedom to operation of an electric machine and improves the output power capability and the efficiency, but its control method becomes more complex because the number of control variables and the operating constraints increase. This paper deals with a control method of DFWM for minimizing the copper loss in maximized operating area. The possible operation area considering all constraints of currents, voltages, and flux is analyzed on the stator currents plane to maximize the operating area. For the minimum copper loss operation in the operating area, different modes are defined and the optimal currents are determined in each mode. Also, the optimal current selection algorithm is proposed to achieve the torque control using the optimal currents. The simulation and experimental results about wound machines are presented to show the feasibility of the proposed control method. Auteurs: Yongsu Han;Jung-Ik Ha; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7700 - 7710 Editeur: IEEE Document complet vers site de l'éditeur
» Control of a City Road Network: Distributed Exact Verification of Traffic Safety
 Résumé:A least-restrictive supervisor for vehicle collision avoidance is a control algorithm that can detect an unsafe maneuver by a set of human-driven or autonomous vehicles, intervening with a corrective action only when needed to avoid a collision. It can help prevent collisions, and facilitate coexistence of autonomous and human-driven vehicles. Such an algorithm is based on a formal verification problem which, unfortunately, is known to be NP-hard in many cases of interest, for instance at traffic intersections. Here, we propose a strategy to dynamically decompose the formal verification problem of a large road network, exploiting vehicle dynamics and the constraints induced by road topology to separate nonconflicting vehicles. We split the global problem into smaller and treatable subproblems, while still allowing to compute an exact solution. We illustrate our results on three different scenarios. Auteurs: Alessandro Colombo;Gabriel Rodrigues de Campos;Fabio Della Rossa; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 4933 - 4948 Editeur: IEEE Document complet vers site de l'éditeur
» Control of Buffer-Induced Current Collapse in AlGaN/GaN HEMTs Using SiNx Deposition
 Résumé:The stoichiometry of low-pressure chemical vapor deposition SiNx surface passivation is shown to change vertical conductivity at the top of the epitaxial stack in GaN-on-Si power high-electron mobility transistors (HEMTs). This changes the charge stored in the carbon-doped GaN layer during high-voltage operation, and allows direct control of buffer-related current collapse in HEMTs. Substrate bias ramps are used to identify the changes in C:GaN charge trapping and vertical leakage. Channel length dependence indicates a lateral conductivity in the C:GaN with a localized increase in vertical conductivity under the ohmic contacts. An optimum SiNx recipe is identified which simultaneously delivers low current collapse and low drain leakage. Auteurs: William M. Waller;Mark Gajda;Saurabh Pandey;Johan J. T. M. Donkers;David Calton;Jeroen Croon;Jan Šonský;Michael J. Uren;Martin Kuball; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4044 - 4049 Editeur: IEEE Document complet vers site de l'éditeur
» Control of Junction Temperature and Its Rate of Change at Thermal Boundaries via Precise Loss Manipulation
 Résumé:To optimize the lifetime of switching power semiconductors, this paper presents a methodology to control power device junction temperature ${T_j}$ and its change during power cycles $\Delta {T_j}$ at thermal boundaries. This paper proposes a supervisory state machine to interrupt nominal system-level control only when temperature bounds are exceeded, and coordinates smooth transitions as ${T_j}(k)$ and $\Delta {T_j}(k)$ approach their respective boundaries. To ensure that thermal states are regulated via precise and independent modulation of conduction and switching loss elements, decoupling methods are proposed. Also proposed is a $\Delta {T_j}$ control law that closes a control loop on the rate of change state ${\bar{\dot{T}}_j}$ , and introduces active thermal capacitance and conductance into the closed-loop thermal system dynamics. Experimental evaluation of the proposed system illustrates well damped ${T_j}(k)$ and $\Delta {T_j}(k)$ responses, and gradual adjustment of the manipulated inputs switching frequency and duty ratio. Finally, comparison with a current limit-based ${T_j}$ regulation method illustrates how the proposed system allows power converters to push harder against their thermal limits. Auteurs: Timothy Allen Polom;Boru Wang;Robert D. Lorenz; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4796 - 4806 Editeur: IEEE Document complet vers site de l'éditeur
» Control Scheme for Open-Ended Induction Motor Drives With a Floating Capacitor Bridge Over a Wide Speed Range
 Résumé:An electric drive for high-speed applications is analyzed in this paper. The drive consists of a dual two-level inverter with a floating bridge, fed by a single voltage source, and a three-phase induction motor with open-ended stator windings. The floating bridge compensates the reactive power of the motor, so that the main inverter operates at unity power factor and fully exploits its current capability. The constant power speed range of the motor can be significantly extended depending on the dc-link voltage of the floating inverter. The details of the control system are examined and the feasibility of an electric drive is experimentally assessed. Auteurs: Michele Mengoni;Albino Amerise;Luca Zarri;Angelo Tani;Giovanni Serra;Domenico Casadei; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4504 - 4514 Editeur: IEEE Document complet vers site de l'éditeur
» Control Strategy for a Modified Cascade Multilevel Inverter With Dual DC Source for Enhanced Drivetrain Operation
 Résumé:This paper presents a new control strategy for a modified cascade multilevel inverter used in drivetrain operations. The proposed inverter is a three-phase bridge with its dc link fed by a dc source (battery), and each phase series-connected to an H-bridge fed with a floating dc source (ultracapacitor). To exploit the potentials of the inverter for enhanced drivetrain performance, a sophisticated yet efficient modulation method is proposed to optimize energy transfer between the dc sources and with the load (induction motor) during typical operations, and to minimize switching losses and harmonics distortion. Detailed analysis of the proposed control method is presented, which is supported by experimental verifications. Auteurs: Maciej S. Bendyk;Patrick Chi-Kwong Luk;Mohammed H. Alkhafaji; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4655 - 4664 Editeur: IEEE Document complet vers site de l'éditeur
» Controllability of Multiagent Networks With Antagonistic Interactions
 Résumé:This paper addresses the controllability of a class of antagonistic multiagent networks with both positive and negative edges. All the agents of the multiagent network run a consensus algorithm using a signed Laplacian. Based on the generalized equitable partition, we propose a graph-theoretic characterization of an upper bound on the controllable subspace. Then, we provide a necessary condition for the controllability of the system and give an algorithm to compute the partition. Furthermore, we prove that for a structurally balanced network, the controllability is equivalent to that of the corresponding all-positive network, if the leaders are chosen from the same vertex set. Several examples are given to illustrate these results. Auteurs: Chao Sun;Guoqiang Hu;Lihua Xie; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5457 - 5462 Editeur: IEEE Document complet vers site de l'éditeur
» Controllable Rotations of Spiraling Elliptic Beams in Anisotropic Linear Media
 Résumé:We study the rotation properties of spiraling elliptic beams in the anisotropy media. Based on the Collins formula, we obtain the exact analytical solution of the spiraling elliptic beams carrying the orbital angular momentum (OAM) to the paraxial wave equation. It is found that the rotation property is closely relevant to the OAM, which can be controlled by the linear anisotropy of media. For an anisotropic media such as the uniaxial crystal, the rotation velocity of spiraling elliptic beams at the output can be controlled only by changing the direction of the optic axis of the uniaxial crystal. Depending on the anisotropy parameter, two rotation modes are predicted for the spiraling elliptic beam. For small anisotropy parameter, the rotation direction of the spiraling elliptic beam is inverted at a certain propagation distance. When the anisotropy parameter is large enough, the invertion of the rotation direction disappears. The results are potentially useful in controlling the optical beams. Auteurs: Guo Liang;Tingjian Jia;Zhanmei Ren; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» Controllable Unidirectional Emission With Double-Resonant Plasmonic Antenna
 Résumé:A double-resonant metal–insulator–metal (MIM) optical antenna is theoretically proposed to control the emission directivity of a dipolar emitter. The nanoantenna consists of an in-plane side-by-side assembling metallic nanobar dimer on the top and a metallic nanoplate on the bottom, separated by a dielectric spacer. Unidirectional and enhanced emission of the emitter is wavelength dependent. It is controllable by changing the phase differences of constituting elements of the antenna, induced by the double magnetic resonances at different wavelengths. The results can be potentially used in near-field sample detection, solar cell, and single-photon source. Auteurs: Fei Liu;Shengyin Ye;Kailiang Zhang;Guangjun Ren; 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
» Controlled Kink Effect in a Novel High-Voltage LDMOS Transistor by Creating Local Minimum in Energy Band Diagram
 Résumé:A new technique to control the kink effect in the high-voltage lateral double-diffused MOSFET (LDMOS) is presented in this paper. This technique produces a local minimum in the band diagram of the proposed structure, which causes the lower barrier height for the holes from the channel to the source region. So, the produced excess holes during the impact ionization process in the channel are reduced significantly. We have called the proposed structure as local minimum energy band LDMOS (LMEB-LDMOS) transistor. The LMEB-LDMOS structure contains modified source and drain regions. The modified source region creates a local minimum in the energy band diagram for absorbing the excess holes, and the modified drain region causes high breakdown voltage (462 V) and low specific on-resistance ( $5.1~\text {m}\Omega \cdot ~\text {cm}^{{{{2}}}})$ . Also, the drift region with lower doping density than drain is deleted in LMEB-LDMOS transistor. The simulation with 2-D ATLAS simulator shows that the proposed structure improves the device performance. Auteurs: Mahsa Mehrad;Meysam Zareiee;Ali A. Orouji; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4213 - 4218 Editeur: IEEE Document complet vers site de l'éditeur
» Controlled Voltage Breakdown in Disconnector Contact System for VFTO Mitigation in Gas-Insulated Switchgear (GIS)
 Résumé:Several methods have been proposed and investigated so far on mitigation of very fast transient overvoltages (VFTO) in gas-insulated switchgear (GIS). The state-of-the-art methods are primarily based on dissipation of the energy associated with electromagnetic waves that the VFTO originate from and are composed of. Present paper reports on an alternative concept of VFTO mitigation based on the principle of controlling voltage conditions preceding voltage breakdown in SF6 gas that leads to VFTO generation. The paper introduces different control algorithms and shows how the algorithms can limit VFTO maximum value and total number of voltage breakdowns during operation of the GIS disconnector. The concept is applied for mitigation of VFTO in ultra-high voltage GIS. As the study case, an 1100 kV test set-up is used as recently reported for Wuhan (China) GIS station, with the disconnector characteristics obtained from 1100 kV development tests. Auteurs: Marcin Szewczyk;Maciej Kuniewski; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2360 - 2366 Editeur: IEEE Document complet vers site de l'éditeur
» Convergence Rate of Distributed ADMM Over Networks
 Résumé:We propose a new distributed algorithm based on alternating direction method of multipliers (ADMM) to minimize sum of locally known convex functions using communication over a network. This optimization problem emerges in many applications in distributed machine learning and statistical estimation. Our algorithm allows for a general choice of the communication weight matrix, which is used to combine the iterates at different nodes. We show that when functions are convex, both the objective function values and the feasibility violation converge with rate $O(1/T)$, where $T$ is the number of iterations. We then show that when functions are strongly convex and have Lipschitz continuous gradients, the sequence generated by our algorithm converges linearly to the optimal solution. In particular, an $\epsilon$-optimal solution can be computed with $O\left(\sqrt{\kappa _f} \log (1/\epsilon) \right)$ iterations, where $\kappa _f$ is the condition number of the problem. Our analysis highlights the effect of network and communication weights on the convergence rate through degrees of the nodes, the smallest nonzero eigenvalue, and operator norm of the communication matrix. Auteurs: Ali Makhdoumi;Asuman Ozdaglar; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5082 - 5095 Editeur: IEEE Document complet vers site de l'éditeur
» Convex Distributed Controller Synthesis for Interconnected Heterogeneous Subsystems Via Virtual Normal Interconnection Matrices
 Résumé:Based on a previously introduced framework for distributed controller synthesis, in this note a novel transformation of interconnection matrices is proposed that enables to consider arbitrary, time-varying and directed interaction topologies. It represents any interconnection as a virtual interconnection matrix that has the property of being normal, i.e., that guarantees the existence of a unitary diagonalizing transformation, which admits to decompose the synthesis problem in terms of the entire interconnected system into problems of subsystem scale, which can then be solved by standard convex multiplier-based gain-scheduling synthesis methods with complexity in the order of a single subsystem. When compared with a method from the literature, the method shows superior performance in both a numerical example and the leader-follower formation control problem of nonlinear quadrocopter models. Auteurs: C. Hoffmann;H. Werner; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5337 - 5342 Editeur: IEEE Document complet vers site de l'éditeur
» Cooperative Modulation Classification for Multipath Fading Channels via Expectation-Maximization
 Résumé:In this paper, we investigate the cooperative modulation classification problem under multipath scenarios with blind channel information. Multipath channels cause severe degradation on the modulation classification performance, which has not yet been thoroughly solved in the existing literature. To address this issue, a likelihood-based classifier using the expectation-maximization algorithm is proposed, which is capable of finding the maximum likelihood estimates of unknown parameters in a tractable way. Furthermore, to evaluate the upper bound performance of the proposed algorithm, the Cramér–Rao lower bounds of the joint estimates of unknown parameters are derived. Extensive simulations show that the classification performance of the proposed algorithm with good initialization scheme is close to the performance upper bound in the high signal-to-noise ratio region. The results also demonstrate that the proposed algorithm provides significant performance improvement in the multipath channels compared with conventional approaches. Auteurs: Jingwen Zhang;Danijela Cabric;Fanggang Wang;Zhangdui Zhong; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6698 - 6711 Editeur: IEEE Document complet vers site de l'éditeur
» Cooperative Raman Spectroscopy for Real-Time In Vivo Nano-Biosensing
 Résumé:In the last few decades, the development of miniature biological sensors that can detect and measure different phenomena at the nanoscale has led to transformative disease diagnosis and treatment techniques. Among others, biofunctional Raman nanoparticles have been utilized in vitro and in vivo for multiplexed diagnosis and detection of different biological agents. However, existing solutions require the use of bulky lasers to excite the nanoparticles and similarly bulky and expensive spectrometers to measure the scattered Raman signals, which limit the practicality and applications of this nano-biosensing technique. In addition, due to the high path loss of the intra-body environment, the received signals are usually very weak, which hampers the accuracy of the measurements. In this paper, the concept of cooperative Raman spectrum reconstruction for real-time in vivo nano-biosensing is presented for the first time. The fundamental idea is to replace the single excitation and measurement points (i.e., the laser and the spectrometer, respectively) by a network of interconnected nano-devices that can simultaneously excite and measure nano-biosensing particles. More specifically, in the proposed system, a large number of nanosensors jointly and distributively collect the Raman response of nano-biofunctional nanoparticles (NBPs) travelling through the blood vessels. This paper presents a detailed description of the sensing system and, more importantly, proves its feasibility, by utilizing the accurate models of optical signal propagation in intra-body environment and low-complexity estimation algorithms. The numerical results show that with a certain density of NBPs, the reconstructed Raman spectrum can be recovered and utilized to accurately extract the targeting intra-body information. Auteurs: Hongzhi Guo;Josep Miquel Jornet;Qiaoqiang Gan;Zhi Sun; Apparue dans: IEEE Transactions on NanoBioscience Date publication: 10.-2017, volume: 16, issue:7, pages: 571 - 584 Editeur: IEEE Document complet vers site de l'éditeur
» Coprime Factors Model Reduction of Spatially Distributed LTV Systems Over Arbitrary Graphs
 Résumé:This technical note is on the model reduction of distributed systems formed by discrete-time, linear time-varying, heterogeneous subsystems interconnected over arbitrary directed graphs and subjected to communication latency. We give two procedures to construct a strongly stable coprime factorization for a strongly stabilizable and strongly detectable system. One of the procedures ensures the contractiveness of the resulting factorization. Then, we apply the structure-preserving balanced truncation method for distributed systems. We illustrate the proposed methods through an example. Auteurs: Dany Abou Jaoude;Mazen Farhood; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5254 - 5261 Editeur: IEEE Document complet vers site de l'éditeur
» Copula-Based Joint Statistical Model for Polarimetric Features and Its Application in PolSAR Image Classification
 Résumé:Polarimetric features are essential to polarimetric synthetic aperture radar (PolSAR) image classification for their better physical understanding of terrain targets. The designed classifiers often achieve better performance via feature combination. However, the simply combination of polarimetric features cannot fully represent the information in PolSAR data, and the statistics of polarimetric features are not extensively studied. In this paper, we propose a joint statistical model for polarimetric features derived from the covariance matrix. The model is based on copula for multivariate distribution modeling and alpha-stable distribution for marginal probability density function estimations. We denote such model by CoAS. The proposed model has several advantages. First, the model is designed for real-valued polarimetric features, which avoids the complex matrix operations associated with the covariance and coherency matrices. Second, these features consist of amplitudes, correlation magnitudes, and phase differences between polarization channels. They efficiently encode information in PolSAR data, which lends itself to interpretability of results in the PolSAR context. Third, the CoAS model takes advantage of both copula and the alpha-stable distribution, which makes it general and flexible to construct the joint statistical model accounting for dependence between features. Finally, a supervised Markovian classification scheme based on the proposed CoAS model is presented. The classification results on several PolSAR data sets validate the efficacy of CoAS in PolSAR image modeling and classification. The proposed CoAS-based classifiers yield superior performance, especially in building areas. The overall accuracies are higher by 5%–10%, compared with other benchmark statistical model-based classification techniques. Auteurs: Hao Dong;Xin Xu;Haigang Sui;Feng Xu;Junyi Liu; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5777 - 5789 Editeur: IEEE Document complet vers site de l'éditeur
» Core Regulation of Long Period Grating Based on Ring-Core Hollow Fiber and the Application of Temperature Sensing
 Résumé:We propose a novel long-period grating (LPG) based on a ring-core hollow fiber (RCHF) filled with functional liquid as a tunable material. The RCHF structure is simple. The effective refractive index tuning characteristics of the liquid-filled RCHF-LPG are investigated. The RCHF-LPG functions as a tunable device filling with a functional liquid. The temperature sensitivities of three RCHF-LPG samples filled with dimethylacetamide (DMA) or DMA–glycerin mixtures are measured. The results show that the sample with high-RI liquid has higher sensitivity to temperature variation. The maximum linear sensitivity of the temperature can reach −618 pm/°C. Auteurs: Bin Dai;Xiang Shen;Jinyan Li;Nengli Dai;Luyun Yang;Xiongwei Hu;Yibo Wang;Yehui Liu;Jinggang Peng;Haiqing Li; 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
» Correction to “The Generalized Stochastic Likelihood Decoder: Random Coding and Expurgated Bounds” [Aug 17 5039-5051]
 Résumé:The purpose of this paper is to handle a gap that was found in the proof of Theorem 2 in the paper “The generalized stochastic likelihood decoder: random coding and expurgated bounds.” Auteurs: Neri Merhav; Apparue dans: IEEE Transactions on Information Theory Date publication: 10.-2017, volume: 63, issue:10, pages: 6827 - 6829 Editeur: IEEE Document complet vers site de l'éditeur
» Corrections to "JANUS-Based Services for Operationally Relevant Underwater Applications" [ IEEE J. Ocean. Eng., 2017, DOI: 10.1109/JOE.2017.2722018]
 Résumé:Presents corrections to the paper, “JANUS-based services for operationally relevant underwater applications,” (Petroccia, R., et al), IEEE J. Ocean. Eng., Jul. 2017. Auteurs: R. Petroccia;J. Alves;G. Zappa; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 1162 - 1162 Editeur: IEEE Document complet vers site de l'éditeur
» Corrections to “JANUS-Based Services for Operationally Relevant Underwater Applications” [ IEEE J. Ocean. Eng., 2017, DOI: 10.1109/JOE.2017.2722018]
 Résumé: Auteurs: R. Petroccia;J. Alves;G. Zappa; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 1162 - 1162 Editeur: IEEE Document complet vers site de l'éditeur
» Corrections to “Density of Traps at the Insulator/III-N Interface of GaN Heterostructure Field-Effect Transistors Obtained by Gated Hall Measurements”
 Résumé:In the above paper [1], equation 5 should read (1) $dV_{B} ={d\left ({ {q\Delta n} }\right )} / {C_{B} }$ Equation 6 should read(2) $D_{it} \left ({ {E_{f} +{q\Delta n}/ {C_{B} }} }\right )\approx \frac {C_{B} C_{I} }{q^{2}}\left [{ {\left ({ {\frac {d\left ({ {q\Delta n} }\right )}{dV_{G} }} }\right )^{-1}-\frac {1}{C_{HF} }} }\right ]$ Auteurs: Shlomo Mehari;Arkady Gavrilov;Moshe Eizenberg;Dan Ritter; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1504 - 1504 Editeur: IEEE Document complet vers site de l'éditeur
» Corrections to “On-Chip Investigation of Phase Noise in Monolithically Integrated Gain-Switched Lasers”
 Résumé:In the above letter equations (2) and (6) are incorrect due to an additional $S$ present within the bracketed term. Auteurs: Justin K. Alexander;Padraic E. Morrissey;Ludovic Caro;Mohamad Dernaika;Niall P. Kelly;Frank H. Peters; Apparue dans: IEEE Photonics Technology Letters Date publication: 10.-2017, volume: 29, issue:20, pages: 1755 - 1755 Editeur: IEEE Document complet vers site de l'éditeur
» Correlated Random Bit Generation Using Chaotic Semiconductor Lasers Under Unidirectional Optical Injection
 Résumé:Correlated random bit generation is investigated using three optically injected chaotic semiconductor lasers. Based on a rate-equation model, a continuous-wave injection first perturbs a common laser into chaos. The common laser then optically injects a pair of response lasers through a public channel unidirectionally. The two response lasers of identical parameters are synchronized. Their chaotic emissions are digitized in yielding correlated random bit streams. As the scheme advantageously involves no feedback loops, the output bits contain no undesirable time-delay information artifacts. Security is ensured as the response lasers produce bits that cannot be extracted using the information in the public channel alone. Output bit streams are generated at a tunable rate of up to about 2 Gbps with randomness verified by a test suite of the National Institute of Standards and Technology. The streams are correlated with a low bit error ratio of less than 4$\%$ , which is sensitive to parameter mismatch between the response lasers. Auteurs: Xiao-Zhou Li;Song-Sui Li;Sze-Chun Chan; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 11 Editeur: IEEE Document complet vers site de l'éditeur
» Correlation of Gate Capacitance with Drive Current and Transconductance in Negative Capacitance Ge PFETs
 Résumé:Correlation of gate capacitance ${C} _{G}$ with drive current ${I} _{\textsf {DS}}$ and transconductance ${G} _{m}$ in negative capacitance (NC) Ge pFETs is first investigated. Hysteresis-free NC Ge pFETs integrated with 4.5-nm HZO achieving the improved ${I} _{\textsf {DS}}$ and ${G} _{m}$ over the control devices are fabricated. A peak in the ${C} _{G}$ versus gate voltage curve is demonstrated in the NC Ge pFET, indicating the NC effect induced by HZO film. It is observed that ${I} _{\textsf {DS}}$ and ${G} _{m}$ of the NC transistors are enhanced as the ${C} _{G}$ peak gets increased. This is attributed to the fact that, as the device operates in the NC region, both ${C} _{G}$ and internal gate voltage amplification are proportional to ${C} _{\textsf {FE}}$ /( ${C} _{\textsf {FE}}+{C}_{\textsf {MOS}}$ ), where ${C} _{\textsf {FE}}$ and ${C} _{\textsf {MOS}}$ are the NC of HZO and the MOS capacitance of the device, respectively. Auteurs: Jing Li;Jiuren Zhou;Genquan Han;Yan Liu;Yue Peng;Jincheng Zhang;Qing-Qing Sun;David Wei Zhang;Yue Hao; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1500 - 1503 Editeur: IEEE Document complet vers site de l'éditeur
» Cost Effective Laser Structuration of Optical Waveguides on Thin Glass Interposer
 Résumé:In order to enhance electro–optical system-in-package capabilities for silicon photonics, a cost effective fabrication process for optical waveguides integration on thin glass substrate interposer is demonstrated. First, a femtosecond laser ablation coupled with a hydrofluoric acid etching is developed to create microgrooves at the glass surface. Second, a dry film lamination followed by chemical mechanical planarization is achieved to define surface optical waveguides by filling the microchannels. Physical characterizations of the fabricated waveguides are performed using optical and scanning electron microscopy. Finally, optical mode profile and loss characterizations confirm the optical functionality of waveguides which prove to be multimodal at 1550 nm. Auteurs: Jean-Marc Boucaud;Folly-Eli Ayi-Yovo;Quentin Hivin;Matthieu Berthomé;Cédric Durand;Frédéric Gianesello;Davide Bucci;Guillaume Ducournau;Jean-François Robillard;Jean-Emmanuel Broquin;Emmanuel Dubois; Apparue dans: Journal of Lightwave Technology Date publication: 10.-2017, volume: 35, issue:20, pages: 4445 - 4450 Editeur: IEEE Document complet vers site de l'éditeur
» Coupled Parametric Effects on Magnetic Fields of Eddy-Current Induced in Non-Ferrous Metal Plate for Simultaneous Estimation of Geometrical Parameters and Electrical Conductivity
 Résumé:Illustrated with a magnetic field based eddy-current (EC) sensor which utilizes an anisotropic magneto-resistive sensor to directly measure the magnetic flux density (MFD) generated by the EC induced in a non-ferrous metal plate, this paper presents a material-independent method for multi-objective estimation of the plate geometrical parameters and/or electrical conductivity using frequency response analysis. The model, which agrees well with a 2-D axis-symmetric finite-element analysis, relates the measured (EC-generated) MFD to three dimensionless parameters (skin depth, plate thickness, and sensor-plate distance) normalized relative to a specified coil design. Data in the material-independent model that provides the basis to investigate the parametric effects on measured MFD can be regrouped in 2-D maps for simultaneously measuring any two of the three parameters. Experimental measurements were conducted on three different materials (Aluminum, Titanium, and Titanium alloy) with different thicknesses and sensor-plate distances between 1 and 5 mm operating in the frequency range from 100 Hz to 42.8 kHz. Experimental results show that the maximum difference between the analytically computed and experimental data is in the order of 5%, and demonstrate that the method has the capability of simultaneously measuring two unknowns out of three geometrical and/or material properties using a material-independent 2-D map. Auteurs: Kok-Meng Lee;Chun-Yeon Lin;Bingjie Hao;Min Li; Apparue dans: IEEE Transactions on Magnetics Date publication: 10.-2017, volume: 53, issue:10, pages: 1 - 9 Editeur: IEEE Document complet vers site de l'éditeur
» Coupling Characteristics of Selective-Infiltration-Based Locally Tapered Photonic Crystal Fiber
 Résumé:We have proposed and experimentally demonstrated a novel compound structure based on selectively infiltrating of a local tapered photonic crystal fiber (TPCF). Theoretical and experimental investigations indicate that tapering photonic crystal fiber (PCF) can change the material refractive index (RI) of silica core, and the RI change can be revealed and proved to influence the effective RI curve of the PCF core mode, which results in the shifting of the phase matching point. Moreover, strong coupling can occur in the infiltrated TPCF due to the increased overlap integral of the involved coupled modes. As application, the proposed configuration based on TPCF has huge potential use in microfluidic, RI, and dual-parameter sensing with high sensitivity, such as ultrahigh strain sensitivity of –139.78 nm/N (–167.74 pm/μϵ). Auteurs: Hu Liang;Zhi Wang;Yange Liu;Hongye Li;Hongwei Zhang; 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
» Coupling Matrix Synthesis of Microwave Differentiators
 Résumé:This letter presents a new design of microwave differentiators using coupled-resonator network. It is synthesized using coupling matrix techniques in the low-pass domain and subsequently transformed and implemented in the bandpass domain. Two numerical examples and one experimental validation are provided to illustrate the approach, which finally validates the proposed approach. Auteurs: Qingfeng Zhang;Fen Xia;Ge Zhang;Yifan Chen; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 879 - 881 Editeur: IEEE Document complet vers site de l'éditeur
» Coupling Quality [Enigmas, etc.]
 Résumé:Various puzzles, games, humorous definitions, or mathematical that should engage the interest of readers. Auteurs: Takashi Ohira; Apparue dans: IEEE Microwave Magazine Date publication: 10.-2017, volume: 18, issue:6, pages: 154 - 154 Editeur: IEEE Document complet vers site de l'éditeur
» Covariance Matrix Estimation for Broadband Underwater Noise
 Résumé:In this paper, a technique is presented for frequency-smoothing the sample covariance matrix observed at the output of a set of elements or beams so as to obtain a frequency-smoothed estimate of the broadband noise covariance matrix due to underwater noise. The smoothing technique is based on a linear model that is derived through analysis of the delay-domain cross covariance of the ambient noise observed by a pair of beams or omnidirectional hydrophones. A simple and robust least squares fitting algorithm allows for extraction of a frequency-smoothed broadband noise covariance estimate even in the presence of narrowband energy. Simulated passive sonar examples demonstrate the validity and utility of the estimate. Possible applications include adaptive beamforming and measuring the vertical/horizontal directionality of diffuse broadband ambient noise sources such as wind and rain. Auteurs: Ryan J. Pirkl;Jason M. Aughenbaugh; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 936 - 947 Editeur: IEEE Document complet vers site de l'éditeur
» Coverage in Heterogeneous Downlink Millimeter Wave Cellular Networks
 Résumé:In this paper, we provide an analytical framework to analyze heterogeneous downlink millimeter-wave (mm-wave) cellular networks consisting of $K$ tiers of randomly located base stations (BSs), where each tier operates in an mm-wave frequency band. Signal-to-interference-plus-noise ratio (SINR) coverage probability is derived for the entire network using tools from stochastic geometry. The distinguishing features of mm-wave communications, such as directional beamforming, and having different path loss laws for line-of-sight and non-line-of-sight links are incorporated into the coverage analysis by assuming averaged biased-received power association and Nakagami fading. By using the noise-limited assumption for mm-wave networks, a simpler expression requiring the computation of only one numerical integral for coverage probability is obtained. Also, the effect of beamforming alignment errors on the coverage probability analysis is investigated to get insight on the performance in practical scenarios. Downlink rate coverage probability is derived as well to get more insights on the performance of the network. Moreover, the effect of deploying low-power smaller cells and the impact of biasing factor on energy efficiency is analyzed. Finally, a hybrid cellular network operating in both mm-wave and $\mu$ -wave frequency bands is addressed. Auteurs: Esma Turgut;M. Cenk Gursoy; Apparue dans: IEEE Transactions on Communications Date publication: 10.-2017, volume: 65, issue:10, pages: 4463 - 4477 Editeur: IEEE Document complet vers site de l'éditeur
» Cross-Entropy Method for Electromagnetic Optimization With Constraints and Mixed Variables
 Résumé:An elegant and simple approach is presented for electromagnetic (EM) optimizations, especially when mixed variables and/or constraints are involved. In mixed-variable optimization, some variables are continuous (can take any value within a range) and others are discrete (can take only values from a database). An example constraint is when the total length of a device under optimization is specified. Our approach can handle such optimization problems and is based on an abstract probabilistic evolutionary optimization algorithm, called the cross-entropy (CE) method. We believe that this is the first application of CE with full-wave EM simulations. A quick performance benchmarking on two test functions was performed to compare convergence of CE and two other established optimization algorithms. Then, the advantages of the CE method when simultaneously optimizing a mix of discrete and continuous variables and imposing geometric constraints are illustrated. Finally, six resonant cavity antennas (RCAs) were optimized, and one was prototyped and tested to verify predicted results. This one-layer-superstrate RCA prototype has a measured peak directivity of 17.6 dBi with a 3 dB directivity bandwidth of 51% and lower sidelobes, outperforming all such prototypes in the literature. Auteurs: Maria Kovaleva;David Bulger;Basit Ali Zeb;Karu P. Esselle; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5532 - 5540 Editeur: IEEE Document complet vers site de l'éditeur
» Crosstalk Analysis of Heterogeneous Multicore Fibers Using Coupled-Mode Theory
 Résumé:Intercore crosstalk of heterogeneous multicore fiber is investigated based on coupled-mode theory. Random twisting model is used for estimating the crosstalk. The crosstalk of two kinds of fibers: triangular lattice 30-core fiber with four kinds of cores and square lattice 32-core fiber with two kinds of cores is investigated both theoretically and experimentally. Unlike previous study, measured crosstalk for all the combinations of cores for both fibers is in good agreement with calculated values with single correlation length, showing the validity of the theoretical model used here. Auteurs: Takeshi Fujisawa;Yoshimichi Amma;Yusuke Sasaki;Shoichiro Matsuo;Kazuhiko Aikawa;Kunimasa Saitoh;Masanori Koshiba; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» Crowdsourcing Sensing to Smartphones: A Randomized Auction Approach
 Résumé:Crowdsourcing to mobile users has emerged as a compelling paradigm for collecting sensing data over a vast area for various monitoring applications. It is of paramount importance for such crowdsourcing paradigm to provide effective incentive mechanisms. State-of-the-art auction mechanisms for crowdsourcing to mobile users are typically deterministic in the sense that for a given sensing job from a crowdsourcer, only a small set of smartphones are selected to perform sensing tasks and the rest are not selected. One apparent disadvantage of such deterministic auction mechanisms is that the diversity with respect to the sensing job is reduced. As a consequence, the quality of the collected sensing data is also decreased. This is due to failure to exploit the intrinsic advantage of the large set of diverse mobile users in a mobile crowdsourcing network. In this paper, we propose a randomized combinatorial auction mechanism for the social cost minimization problem, which is proven to be NP-hard. We design an approximate task allocation algorithm that is near optimal with polynomial-time complexity and use it as a building block to construct the whole randomized auction mechanism. Compared with deterministic auction mechanisms, the proposed randomized auction mechanism increases the diversity in contributing users for a given sensing job. We carry out both solid theoretical analysis and extensive numerical studies and show that our randomized auction mechanism achieves approximate truthfulness, individual rationality, and high computational efficiency. Auteurs: Juan Li;Yanmin Zhu;Yiqun Hua;Jiadi Yu; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 10.-2017, volume: 16, issue:10, pages: 2764 - 2777 Editeur: IEEE Document complet vers site de l'éditeur
» Cryptanalysis of Controlled Bidirectional Quantum Secure Direct Communication Network Using Classical XOR Operation and Quantum Entanglement
 Résumé:The multi-user controlled bidirectional quantum secure direct communication network protocol based on classical EXCLUSIVE-OR operation and quantum entanglement is analyzed. It is shown that this protocol has the information leakage problem, that is, one half of the information the users transmit is leaked out unconsciously. Furthermore, it is also weak against the intercept-measure-resend attack and the Controlled-Not operation attack from an outside adversary, and the different initial state attack from the controller. Auteurs: Zhihao Liu;Hanwu Chen; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2202 - 2205 Editeur: IEEE Document complet vers site de l'éditeur
» Cumulation of High-Current Electron Beams: Theory and Experiment
 Résumé:High-power electron beam cumulation in a relativistic vacuum diode with a ring-type cathode is considered. The term “electron beam cumulation” here means electron beam self-focusing accompanied with multifold beam current density increase on the beam axis compared to the average current density in the cathode-anode gap. Space-charge repulsion of electrons emitted by the explosive-emission plasma on the inner edge of the cathode is shown to be the origin of this cumulation mechanism. Current density in the vicinity of beam axis is evaluated for different cathode inner diameter values both numerically and experimentally. Cathode with eccentric apertures of different diameters is studied experimentally. Auteurs: Sergei Anishchenko;Vladimir Baryshevsky;Nikolai Belous;Alexandra Gurinovich;Elizaveta Gurinovich;Evgeny Gurnevich;Pavel Molchanov; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2739 - 2743 Editeur: IEEE Document complet vers site de l'éditeur
» Cumulative Dual Foreground Differences for Illegally Parked Vehicles Detection
 Résumé:Illegally parked vehicles on the urban road may create a traffic flow problem as well as a potential traffic accident, such as crashing between parked and other vehicles. Thus, the intelligent traffic monitoring system should be able to prevent this situation by integrating an illegally parked vehicle detection module. However, implementing such a module becomes more challenging due to road environments, such as weather conditions, occlusion, and illumination changing. Hence, this work addresses a method to implement an illegally parked vehicle detection based on the cumulative dual foreground differences from the short- and long-term background models, temporal analysis, vehicle detector, and tracking. The extensive experiments were conducted using both iLIDS and our proposed datasets to evaluate the effectiveness of the proposed method by comparing with other methods. The results showed that the method is effective in detecting illegally parked vehicles and can be considered as part of the intelligent traffic monitoring system. Auteurs: Wahyono;Kang-Hyun Jo; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2464 - 2473 Editeur: IEEE Document complet vers site de l'éditeur
» Current Noise Cancellation for Bearing Fault Diagnosis Using Time Shifting
 Résumé:The stator current of a typical induction motor involves the supply fundamental and its harmonics existing before and after the presence of a bearing defect, and much of the information they contain is not related to the bearing defect. In this sense, they are basically noise to bearing fault diagnosis problem. This paper develops a current noise cancellation method using time shifting. Current residue is obtained by adding digital current signal to its own sample-delayed representation as an antinoise component. The amount of the sample delay is only dependent upon the supply frequency and the sampling rate. This amount is set to eliminate the supply fundamental and its odd multiple harmonics. After obtaining the current residue, through the spectral analysis of the envelope of the current residue, the characteristic fault frequencies for a defective bearing can be revealed. To show the superiority, the developed method is experimentally compared with three of the current-based methods in the literature. Experimental results for the defects in the outer raceway, the inner raceway, and the ball of a bearing verify the merits and effectiveness of the developed method. Auteurs: Fardin Dalvand;Satar Dalvand;Fatemeh Sharafi;Michael Pecht; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8138 - 8147 Editeur: IEEE Document complet vers site de l'éditeur
» Current-Detection-Independent Dead-Time Compensation Method Based on Terminal Voltage A/D Conversion for PWM VSI
 Résumé:Dead-time insertion increases noise and torque pulsation in motors under open-loop constant V/f control, and it results in instability in motors under sensorless field-orientated control or direct torque control at low speed, degrading performance of motor drive systems. In order to overcome the drawback of dead-time insertion, a novel current-detection-independent dead-time compensation technique based on terminal voltage A/D conversion is proposed in this paper. Both current polarity and compensation time can be extracted from the sampled terminal voltage. Experiments on an induction motor rated at 210 V, 2.2 kW demonstrated the proposed technique can significantly improve the performance of the fixed compensation, online compensation, and even the feedback compensation method. The proposed scheme does not rely on current sensors, and thus can be applied to both open-loop and closed-loop motor drive systems. When combined with the fixed compensation method, the performance of the proposed technique is even comparable with the feedback compensation method within a large frequency range, making it very attractive for open-loop constant V/f drives where current sensors are not available. Auteurs: Gang Liu;Dafang Wang;Yi Jin;Miaoran Wang;Peng Zhang; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7689 - 7699 Editeur: IEEE Document complet vers site de l'éditeur
» Current-Feed Single-Switch Forward Resonant DC Transformer (DCX) With Secondary Diode-Clamping
 Résumé:A simple current-feed single-switch forward resonant converter with secondary diode-clamping is proposed for low-power high-density bus converter applications in this paper. The quasi-zero-voltage-switching turn-on and quasi-zero-current-switching (ZCS) turn-off for switch are both achieved. Due to the quasi-ZCS turn-off , the high voltage spike in traditional single forward converter with a reset winding is much reduced. A small diode connected to the output capacitor is utilized to clamp the voltage stress of the switches. The operating principle of the proposed converter is analyzed and a MHz 66 W 24 V-to-12 V prototype with all Si devices is built up. Experimental results show good soft-switching features, and the prototype achieves 95.3% peak efficiency with 270 W/in3 power density. Auteurs: Wei Qin;Xinke Wu;Junming Zhang; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7790 - 7799 Editeur: IEEE Document complet vers site de l'éditeur
» CUTE Mote, A Customizable and Trustable End-Device for the Internet of Things
 Résumé:The ubiquitous connectivity of the low-end devices in the Internet of Things (IoT) brings new challenges over the traditional wireless sensor networks’ architectures. Such challenges require not only security and privacy-related features, but also solutions to handle the ever-growing amount of data transferred over the network. However, performing such tasks on resource constrained devices is not straightforward. The need for energy-efficient devices, while preserving their performance and security capabilities, requires new solutions at the architectural level of the wireless device. This paper proposes a heterogeneous architecture that targets low-end and resource constrained IoT devices, combining a hardcore microcontroller unit (MCU) and a reconfigurable computing unit (RCU) with an IEEE 802.15.4 radio transceiver. The MCU hosts an embedded operating system with an IoT-enabled network stack, and exploits the available field-programmable gate array technology to implement the RCU and to deploy customized sensing- and network-related accelerators, offloading heavy, and/or complex software tasks to dedicated hardware blocks. The customizable and trustable end-device mote was implemented using the proposed architecture and the achieved results demonstrates the benefits, both in terms of performance and energy, of accelerating network-related tasks in always-connected resource constrained IoT devices. Auteurs: Tiago Gomes;Filipe Salgado;Adriano Tavares;Jorge Cabral; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6816 - 6824 Editeur: IEEE Document complet vers site de l'éditeur
» CVaR-Constrained Optimal Bidding of Electric Vehicle Aggregators in Day-Ahead and Real-Time Markets
 Résumé:An electric vehicle aggregator (EVA) that manages geographically dispersed electric vehicles offers an opportunity for the demand side to participate in electricity markets. This paper proposes an optimization model to determine the day-ahead inflexible bidding and real-time flexible bidding under market uncertainties. Based on the relationship between market price and bid price, the proposed optimal bidding model of EVA aims to minimize the conditional expectation of electricity purchase cost in two markets considering price volatility. Moreover, the penalty cost of the deviation between the bidding quantities is included to avoid large power variation and arbitrage. The conditional expectation optimization model is formulated as an expectation minimization problem with the conditional value-at-risk constraints. Based on the price data in the PJM market, simulation results verify that our model is a decision-making tool in electricity markets, which can help market players comprehend the variants of bid price, expected cost and probability of successful bidding. Auteurs: Hongming Yang;Sanhua Zhang;Jing Qiu;Duo Qiu;Mingyong Lai;ZhaoYang Dong; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2555 - 2565 Editeur: IEEE Document complet vers site de l'éditeur
» Cybersecurity and Rural Electric Power Systems: Considering Competing Requirements for Implementing a Protection Plan
 Résumé:Cybersecurity is a topic of increasing importance and interest to small utility operators like rural electric associations. Cyberattacks are a threat to our society's functioning, and cybersecurity is an urgent need in areas that include national security, business operations, and regulatory compliance. Several fundamental concepts can guide an operator when implementing a cybersecurity plan. Operators must consider the competing requirements of confidentiality, integrity, availability (CIA), and cost. They must also consider the potential of impact levels for an incident. While implementing a cybersecurity plan, operators will constantly identify adversaries, threats, vulnerabilities, consequences, and risks. They will implement physical, technical, and administrative controls to protect networks and other assets, detect attacks, respond to those attacks, and recover from any damage. The process will be continuous as operators respond to the changing environment. Auteurs: Paul Kaster;Pankaj P.K. Sen; Apparue dans: IEEE Industry Applications Magazine Date publication: 10.-2017, volume: 23, issue:5, pages: 14 - 20 Editeur: IEEE Document complet vers site de l'éditeur
» Cybersecurity in Power Systems
 Résumé:Did you know that cyberattackers have already created outages in Ukraine, not once but twice? On 23 December 2015, cyberintruders at three electric distribution companies in Ukraine opened breakers, creating a power outage that affected 225,000 people. Power was restored in approximately 6 h, as field personnel manually closed the breakers. Auteurs: Michael F. Ahern; Apparue dans: IEEE Potentials Date publication: 10.-2017, volume: 36, issue:5, pages: 8 - 12 Editeur: IEEE Document complet vers site de l'éditeur
» Daily Clearness Index Profiles Cluster Analysis for Photovoltaic System
 Résumé:Due to various weather perturbation effects, the stochastic nature of real-life solar irradiance has been a major issue for solar photovoltaic (PV) system planning and performance evaluation. This paper aims to discover clearness index (CI) patterns and to construct centroids for the daily CI profiles. This will be useful in being able to provide a standardized methodology for PV system design and analysis. Four years of solar irradiance data collected from Johannesburg (26.21 S, 28.05 E), South Africa are used for the case study. The variation in CI could be significant in different seasons. In this paper, cluster analysis with Gaussian mixture models (GMM), K-Means with Euclidean distance (ED), K-Means with Manhattan distance, Fuzzy C-Means (FCM) with ED, and FCM with dynamic time warping (FCM DTW) are performed for the four seasons. A case study based on sizing a stand-alone solar PV and storage system with anaerobic digestion biogas power plants is used to examine the usefulness of the clustering results. It concludes that FCM DTW and GMM can determine the correct PV farm rated capacity with an acceptable energy storage capacity, with 36 and 46 rather than 1457 solar irradiance profiles, respectively. Auteurs: Chun Sing Lai;Youwei Jia;Malcolm D. McCulloch;Zhao Xu; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2322 - 2332 Editeur: IEEE Document complet vers site de l'éditeur
» Damping Dependence of Spin-Torque Effects in Thermally Assisted Magnetization Reversal
 Résumé:Thermal fluctuations of nanomagnets driven by spin-polarized currents are treated via the Landau–Lifshitz–Gilbert equation as generalized to include both the random thermal noise field and Slonczewski spin-transfer torque terms. The magnetization reversal time of such a nanomagnet is then evaluated for wide ranges of damping by using a method which generalizes the solution of the so-called Kramers turnover problem for mechanical Brownian particles, thereby bridging the very low damping and intermediate damping Kramers escape rates, to the analogous magnetic turnover problem. The reversal time is then evaluated for a nanomagnet with the free energy density given in the standard form of superimposed easy-plane and in-plane easy-axis anisotropies with the dc bias field along the easy axis. Auteurs: Y. P. Kalmykov;D. Byrne;W. T. Coffey;W. J. Dowling;S. V. Titov;J. E. Wegrowe; 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
» Data Backup Optimization for Nonvolatile SRAM in Energy Harvesting Sensor Nodes
 Résumé:Nonvolatile static random access memory (nvSRAM) has been widely investigated as a promising on-chip memory architecture in energy harvesting sensor nodes, due to zero standby power, resilience to power failures, and fast read/write operations. However, conventional approaches back up all data from static random access memory into nonvolatile memory when power failures happen. It leads to significant energy overhead and peak inrush current, which has a negative impact on the system performance and circuit reliability. This paper proposes a holistic data backup optimization to mitigate these problems in nvSRAM, consisting of a partial backup algorithm and a run-time adaptive write policy. A statistic dead-block predictor is employed to achieve dead block identification with trivial hardware overhead. An adaptive policy is used to switch between write-back and write-through strategy to reduce the rollback induced by backup failures. Experimental results show that the proposed scheme improves the performance by 4.6% on average while the backup power consumption and the inrush current are reduced by 38.1% and 54% on average compared to the full backup scheme. What is more, the backup capacitor size for energy buffer can be reduced by 40% on average under the same performance constraint. Auteurs: Yongpan Liu;Jinshan Yue;Hehe Li;Qinghang Zhao;Mengying Zhao;Chun Jason Xue;Guangyu Sun;Meng-Fan Chang;Huazhong Yang; Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Date publication: 10.-2017, volume: 36, issue:10, pages: 1660 - 1673 Editeur: IEEE Document complet vers site de l'éditeur
» Data Leakage Prevention for Secure Cross-Domain Information Exchange
 Résumé:Cross-domain information exchange is an increasingly important capability for conducting efficient and secure operations, both within coalitions and within single nations. A data guard is a common cross-domain sharing solution that inspects the security labels of exported data objects and validates that they are such that they can be released according to policy. While we see that guard solutions can be implemented with high assurance, we find that obtaining an equivalent level of assurance in the correctness of the security labels easily becomes a hard problem in practical scenarios. Thus, a weakness of the guard-based solution is that there is often limited assurance in the correctness of the security labels. To mitigate this, guards make use of content checkers such as dirty word lists as a means of detecting mislabeled data. To improve the overall security of such cross-domain solutions, we investigate more advanced content checkers based on the use of machine learning. Instead of relying on manually specified dirty word lists, we can build data-driven methods that automatically infer the words associated with classified content. However, care must be taken when constructing and deploying these methods as naive implementations are vulnerable to manipulation attacks. In order to provide a better context for performing classification, we monitor the incoming information flow and use the audit trail to construct controlled environments. The usefulness of this deployment scheme is demonstrated using a real collection of classified and unclassified documents. Auteurs: Kyrre Wahl Kongsgard;Nils Agne Nordbotten;Federico Mancini;Raymond Haakseth;Paal E. Engelstad; Apparue dans: IEEE Communications Magazine Date publication: 10.-2017, volume: 55, issue:10, pages: 37 - 43 Editeur: IEEE Document complet vers site de l'éditeur
» Data-Based Predictive Optimization for Byproduct Gas System in Steel Industry
 Résumé:In light of significant complexity of the byproduct gas system in steel industry (which limits an ability to establish its physics-based model), this paper proposes a data-based predictive optimization (DPO) method to carry out real-time adjusting for the gas system. Two stages of the method, namely, the prediction modeling and real-time optimization, are involved. At the prediction stage, the states of the optimized objectives, the consumption of the outsourcing natural gas and oil, the power generation, and the tank levels, are forecasted based on a proposed mixed Gaussian kernel-based prediction intervals (PIs) construction model. The Jacobian matrix of this model is represented by a kernel matrix through derivation, which greatly facilitates the subsequent calculation. At the second stage, a rolling optimization based on a mathematical programming technique involving continuous and integer decision-making variables is developed via the PIs. To demonstrate the performance of the DPO method, the practical data coming from the energy center of a steel plant are employed. The results show that the proposed DPO method can supply the human operators with effective solution for secure and economically justified optimization of the gas system.Note to Practitioners—Given that the byproduct gas system in steel industry can hardly be described by a physics or mechanism-based model, its operation is widely realized by the experience-based manual measure at present, which exhibits a very low automation level. Since a large number of real-time energy data have been accumulated by the existing SCADA system implemented in most of steel plants, a novel data-driven real-time predictive optimization method is proposed in this study.The proposed method aims at the short term energy optimization, thus the sample interval of the real-time data acquired from the SCADA system is set as 1 minute. The application system can provide the r- lling optimized solution via real-time predicting the running circumstances of the gas system. Therefore, it is required for the plant in advance to implement the SCADA system for the energy data acquisition, and the sampling interval should be less than or equal to 1 minute. Furthermore, it is necessary for the sample data to complete the preliminary processing such as data imputation if needed since there are usually a large number of possible missing data points existed in the SCADA system of the production practice. Because such preliminary processing for the sample data belongs to a class of generic methods, this study avoids the redundant technical introduction. Auteurs: Jun Zhao;Chunyang Sheng;Wei Wang;Witold Pedrycz;Quanli Liu; Apparue dans: IEEE Transactions on Automation Science and Engineering Date publication: 10.-2017, volume: 14, issue:4, pages: 1761 - 1770 Editeur: IEEE Document complet vers site de l'éditeur
» Data-Driven Distributed Local Fault Detection for Large-Scale Processes Based on the GA-Regularized Canonical Correlation Analysis
 Résumé:Large-scale processes have become common, and fault detection for such processes is imperative. This work studies the data-driven distributed local fault detection problem for large-scale processes with interconnected subsystems and develops a genetic algorithm (GA)-regularized canonical correlation analysis (CCA)-based distributed local fault detection scheme. For each subsystem, the GA-regularized CCA is first performed with its all coupled systems, which aims to preserve the maximum correlation with the minimal communication cost. A CCA-based residual is then generated, and corresponding statistic is constructed to achieve optimal fault detection for the subsystem. The distributed fault detector performs local fault detection for each subsystem using its own measurements and the information provided by its coupled subsystems and therefore exhibits a superior monitoring performance. The regularized CCA-based distributed fault detection approach is tested on a numerical example and the Tennessee Eastman benchmark process. Monitoring results indicate the efficiency and feasibility of the proposed approach. Auteurs: Qingchao Jiang;Steven X. Ding;Yang Wang;Xuefeng Yan; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8148 - 8157 Editeur: IEEE Document complet vers site de l'éditeur
» DC and RF Performance of AlGaN/GaN/SiC MOSHEMTs With Deep Sub-Micron T-Gates and Atomic Layer Epitaxy MgCaO as Gate Dielectric
 Résumé:In this letter, we report on the dc and RF performance of AlGaN/GaN metal-oxide-semiconductor high-electron mobility transistors (MOSHEMTs) with various gate lengths ( ${L}_{\mathsf {G}}$ ) from 90 to 500 nm using atomic-layer-epitaxy single crystalline Mg0.25Ca0.75O as gate dielectric. The 90-nm T-gate MOSHEMT simultaneously demonstrates a ft/fmax of 113/160 GHz with high on/off ratio of $5\times 10^{8}$ . The on/off ratio increases to $2\times 10^{11}$ at ${L}_{\mathsf {G}}=350$ nm by reducing short channel effects. The gate leakage current is around 10−11 A/mm at off-state and 10−5 A/mm at on-state. A 160 nm ${L}_{\mathsf {G}}$ MOSHEMT also exhibits an output power density of 4.18 W/mm at ${f} = 35$ GHz and ${V}_{\mathsf {DS}}=20$ V. MgCaO demonstrates to be a promising dielectric for GaN MOS technology in serving as the surface passivation layer and reducing the gate leakage current while maintaining high RF performances for high-power applications. Auteurs: Hong Zhou;Xiabing Lou;Karynn Sutherlin;Jarren Summers;Sang Bok Kim;Kelson D. Chabak;Roy G. Gordon;Peide D. Ye; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1409 - 1412 Editeur: IEEE Document complet vers site de l'éditeur
» DC-Link Current and Torque Ripple Optimized Self-Sensing Control of Interior Permanent-Magnet Synchronous Machines for Hybrid and Electrical Vehicles
 Résumé:To minimize the ripple on the dc-link current and torque due to carrier signal injections, conventional saliency based self-sensing control schemes using voltage and current carrier signals for interior permanent magnet synchronous machines (IPMSMs) are optimized in this paper. Carrier signal oriented coordinates are introduced to model the high-frequency behavior of IPMSMs and are used for the analysis and signal processing of proposed methods. Moreover, stability issues are discussed in this paper. Experimental results on a commercial high voltage inverter for application in hybrid and electrical vehicles confirm the applicability of the proposed methods. Auteurs: Lei Chen;Gunther Götting;Ingo Hahn; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4536 - 4546 Editeur: IEEE Document complet vers site de l'éditeur
» DCO-OFDM Signals With Derated Power for Visible Light Communications Using an Optimized Adaptive Network-Based Fuzzy Inference System
 Résumé:Direct current-biased optical orthogonal frequency division multiplexing (DCO-OFDM) signals used in visible light communications suffer from high peak-to-average-power ratio (PAPR) or cubic metric (CM). It strongly degrades the performance due to the great back-off necessary to avoid the clipping effect in the light-emitting diode. Thus, PAPR and CM reduction techniques become crucial to improve the system performance. In this paper, an adaptive network-based fuzzy inference system (ANFIS) is used to obtain efficient DCO-OFDM signals with a low power envelope profile. First, signals specially designed for DCO-OFDM with very low CM, as the ones obtained from the raw cubic metric (RCM)–active constellation extension method, are used to train the fuzzy systems in time and frequency domains. Second, after the off-line training, the ANFIS can generate a real-valued signal in a one-shot way with 8.9 dB of RCM reduction from the original real-valued signal, which involves a gain in the input power back off larger than 2.8 dB, an illumination-to-communication conversion efficiency gain of more than 35% and considerable improvements in bit error rate. Auteurs: Borja Genovés Guzmán;Víctor P. Gil Jiménez; Apparue dans: IEEE Transactions on Communications Date publication: 10.-2017, volume: 65, issue:10, pages: 4371 - 4381 Editeur: IEEE Document complet vers site de l'éditeur
» Deadline-Aware Opportunistic Network Coding for Multi-Relay-Aided Single-Source Single-Destination Network
 Résumé:An opportunistic network coding (NC) scheme is proposed for the multi-relay-aided single-source single-destination network with transmission deadline. With the help of matrix analysis, the lower bound of decoding failure probability of the proposed scheme is given. Simulation results show that: 1) the proposed scheme outperforms NC based on direct recoding scheme and the lower bound is tight when the source-to-relay channel erasure probability is relatively small and 2) given fixed network parameters, the optimal number of systematic packets delivered within deadline could be determined by using the derived bound for maximizing the throughput. Auteurs: Guojie Hu;Kui Xu;Youyun Xu; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2282 - 2285 Editeur: IEEE Document complet vers site de l'éditeur
» Decomposing Joint Distortion for Adaptive Steganography
 Résumé:Recent advances on adaptive steganography imply that the security of steganography can be improved by exploiting the mutual impact of modifications between adjacent cover elements, such as pixels of images, which is called a nonadditive distortion model. In this paper, we propose a framework for nonadditive distortion steganography by defining joint distortion on pixel blocks. To reduce the complexity for minimizing joint distortion, we design a coding method to decompose the joint distortion (abbreviated to DeJoin) into distortion on individual pixels; thus, the message can be efficiently embedded with syndrome-trellis codes. We prove that DeJoin can approach the lower bound of joint distortion. As an example, we define joint distortion according to the principle of synchronizing modification direction and then design steganographic algorithms with DeJoin. The experimental results show that the proposed method outperforms previous nonadditive distortion steganography when resisting the state-of-the-art steganalysis. Auteurs: Weiming Zhang;Zhuo Zhang;Lili Zhang;Hanyi Li;Nenghai Yu; Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology Date publication: 10.-2017, volume: 27, issue:10, pages: 2274 - 2280 Editeur: IEEE Document complet vers site de l'éditeur
» Decoupled Uplink-Downlink User Association in Multi-Tier Full-Duplex Cellular Networks: A Two-Sided Matching Game
 Résumé:In multi-tier cellular networks, user performance in both the downlink (DL) and uplink (UL) transmissions depend on the transmit powers of the base stations (BSs) in different network tiers, users' distances, and non-uniform traffic loads of different BSs. In such a network, decoupled UL-DL user association (DUDe), which allows users to associate with different BSs for UL and DL transmissions, can be used to optimize network performance. Again, in-band full-duplex (FD) communication is considered as a promising technique to improve the spectral efficiency of future multi-tier fifth generation (5G) cellular networks. Nonetheless, due to UL-to-DL and DL-to-UL interferences arising due to FD communications, the performance gains of DUDe in FD multi-tier networks are inconspicuous. To this end, this paper develops a comprehensive framework to analyze the usefulness of DUDe in a full-duplex multi-tier cellular network. We first formulate a joint UL and DL user association problem (with the provisioning for decoupled association) that maximizes the sum-rate for UL and DL transmission of all users. Since the formulated problem is a mixed-integer non-linear programming (MINLP) problem, we invoke approximations and binary constraint relaxations to convert the problem into a Geometric Programming (GP) problem that is solved by using Karush-Kuhn-Tucker (KKT) optimality conditions. Given the centralized nature and complexity of the GP problem, we formulate a distributed two-sided iterative matching game and obtain a solution of the game. In this game, the users and BSs rank one another using preference metrics that are subject to the externalities (i.e., dynamic interference conditions). The solution of the game is guaranteed to converge and provides Pareto-optimal stable associations. Finally, we derive efficient light-weight versions of the iterative matching solution, i.e., non-iterative matching and sequential UL-DL matching algorithms. The performances of the solutions a- e evaluated in terms of aggregate UL and DL rates of all users, the number of unassociated users, and the number of coupled/decoupled associations. Simulation results demonstrate the efficacy of the proposed algorithms over the centralized GP solution as well as traditional coupled and decoupled user association schemes. Auteurs: Silvia Sekander;Hina Tabassum;Ekram Hossain; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 10.-2017, volume: 16, issue:10, pages: 2778 - 2791 Editeur: IEEE Document complet vers site de l'éditeur
» Decoy-State Reference-Frame-Independent Measurement-Device-Independent Quantum Key Distribution With Biased Bases
 Résumé:Reference-frame-independent measurement-device-independent quantum key distribution (RFI-MDI-QKD) can eschew the alignment of reference frames in practical systems and defeat all potential detector side channel attacks. Here, we propose the decoy-state RFI-MDI-QKD protocol with biased bases. In this protocol, two legitimate parties Alice and Bob prepare signal states in $Z$, $X$, and $Y$ bases and decoy states in $X$ and $Y$ bases, which avoids the futility in $Z$ basis for decoy states and simplifies the operation of existing systems. Considering the security against coherent attacks with statistical fluctuations, we investigate the performance of the decoy-state RFI-MDI-QKD protocol with biased bases in the environment of unknown and slowly drifting reference frames and make comparisons with the original decoy-state RFI-MDI-QKD protocol under the same conditions. Simulation results show that the proposed protocol can increase the achievable secret key rate and transmission distance obviously compared with the original protocol, which is very promising in real-life QKD systems. Auteurs: Chun-Mei Zhang;Jian-Rong Zhu;Qin Wang; Apparue dans: Journal of Lightwave Technology Date publication: 10.-2017, volume: 35, issue:20, pages: 4574 - 4578 Editeur: IEEE Document complet vers site de l'éditeur
» Deep Conditional Random Field Approach to Transmembrane Topology Prediction and Application to GPCR Three-Dimensional Structure Modeling
 Résumé:Transmembrane proteins play important roles in cellular energy production, signal transmission, and metabolism. Many shallow machine learning methods have been applied to transmembrane topology prediction, but the performance was limited by the large size of membrane proteins and the complex biological evolution information behind the sequence. In this paper, we proposed a novel deep approach based on conditional random fields named as dCRF-TM for predicting the topology of transmembrane proteins. Conditional random fields take into account more complicated interrelation between residue labels in full-length sequence than HMM and SVM-based methods. Three widely-used datasets were employed in the benchmark. DCRF-TM had the accuracy 95 percent over helix location prediction and the accuracy 78 percent over helix number prediction. DCRF-TM demonstrated a more robust performance on large size proteins (>350 residues) against 11 state-of-the-art predictors. Further dCRF-TM was applied to ab initio modeling three-dimensional structures of seven-transmembrane receptors, also known as G protein-coupled receptors. The predictions on 24 solved G protein-coupled receptors and unsolved vasopressin V2 receptor illustrated that dCRF-TM helped abGPCR-I-TASSER to improve TM-score 34.3 percent rather than using the random transmembrane definition. Two out of five predicted models caught the experimental verified disulfide bonds in vasopressin V2 receptor. Auteurs: Hongjie Wu;Kun Wang;Liyao Lu;Yu Xue;Qiang Lyu;Min Jiang; Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics Date publication: 10.-2017, volume: 14, issue:5, pages: 1106 - 1114 Editeur: IEEE Document complet vers site de l'éditeur
» Deep Fully Convolutional Network-Based Spatial Distribution Prediction for Hyperspectral Image Classification
 Résumé:Most of the existing spatial-spectral-based hyperspectral image classification (HSIC) methods mainly extract the spatial-spectral information by combining the pixels in a small neighborhood or aggregating the statistical and morphological characteristics. However, those strategies can only generate shallow appearance features with limited representative ability for classes with high interclass similarity and spatial diversity and therefore reduce the classification accuracy. To this end, we present a novel HSIC framework, named deep multiscale spatial-spectral feature extraction algorithm, which focuses on learning effective discriminant features for HSIC. First, the well pretrained deep fully convolutional network based on VGG-verydeep-16 is introduced to excavate the potential deep multiscale spatial structural information in the proposed hyperspectral imaging framework. Then, the spectral feature and the deep multiscale spatial feature are fused by adopting the weighted fusion method. Finally, the fusion feature is put into a generic classifier to obtain the pixelwise classification. Compared with the existing spectral-spatial-based classification techniques, the proposed method provides the state-of-the-art performance and is much more effective, especially for images with high nonlinear distribution and spatial diversity. Auteurs: Licheng Jiao;Miaomiao Liang;Huan Chen;Shuyuan Yang;Hongying Liu;Xianghai Cao; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5585 - 5599 Editeur: IEEE Document complet vers site de l'éditeur
» Deep Learning of Graphs with Ngram Convolutional Neural Networks
 Résumé:Convolutional Neural Network (CNN) has gained attractions in image analytics and speech recognition in recent years. However, employing CNN for classification of graphs remains to be challenging. This paper presents the Ngram graph-block based convolutional neural network model for classification of graphs. Our Ngram deep learning framework consists of three novel components. First, we introduce the concept of $n$ -gram block to transform each raw graph object into a sequence of $n$ -gram blocks connected through overlapping regions. Second, we introduce a diagonal convolution step to extract local patterns and connectivity features hidden in these $n$ -gram blocks by performing $n$ -gram normalization. Finally, we develop deeper global patterns based on the local patterns and the ways that they respond to overlapping regions by building a $n$ -gram deep learning model using convolutional neural network. We evaluate the effectiveness of our approach by comparing it with the existing state of art methods using five real graph repositories from bioinformatics and social networks domains. Our results show that the Ngram approach outperforms existing methods with high accuracy and comparable performance. Auteurs: Zhiling Luo;Ling Liu;Jianwei Yin;Ying Li;Zhaohui Wu; Apparue dans: IEEE Transactions on Knowledge and Data Engineering Date publication: 10.-2017, volume: 29, issue:10, pages: 2125 - 2139 Editeur: IEEE Document complet vers site de l'éditeur
» Deep TSK Fuzzy Classifier With Stacked Generalization and Triplely Concise Interpretability Guarantee for Large Data
 Résumé:Although Takagi–Sugeno–Kang (TSK) fuzzy classifier has been applied to a wide range of practical scenarios, how to enhance its classification accuracy and interpretability simultaneously is still a challenging task. In this paper, based on the powerful stacked generalization principle, a deep TSK fuzzy classifier (D-TSK-FC) is proposed to achieve the enhanced classification accuracy and triplely concise interpretability for fuzzy rules. D-TSK-FC consists of base-building units. Just like the existing popular deep learning, D-TSK-FC can be built in a layer-by-layer way. In terms of the stacked generalization principle, the training set plus random shifts obtained from random projections of prediction results of current base-building unit are presented as the input of the next base-building unit. The hidden layer in each base-building unit of D-TSK-FC is represented by triplely concise interpretable fuzzy rules in the sense of randomly selected features with the fixed five fuzzy partitions, random rule combinations, and the same input space kept in every base-building unit of D-TSK-FC. The output layer of each base-building unit can be learnt quickly by least learning machine (LLM). Besides, benefiting from LLM, D-TSK-FC's deep learning can be well scaled up for large datasets. Our extensive experimental results witness the power of the proposed deep TSK fuzzy classifier. Auteurs: Ta Zhou;Fu-Lai Chung;Shitong Wang; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 10.-2017, volume: 25, issue:5, pages: 1207 - 1221 Editeur: IEEE Document complet vers site de l'éditeur
» DeepCloud: Ground-Based Cloud Image Categorization Using Deep Convolutional Features
 Résumé:Accurate ground-based cloud image categorization is a critical but challenging task that has not been well addressed. One of the essential issues that affect the performance is to extract the representative visual features. Nearly all of the existing methods rely on the hand-crafted descriptors (e.g., local binary patterns, CENsus TRsansform hISTogram, and scale-invariant feature transform). Their limited discriminative power indeed leads to the unsatisfactory performance. To alleviate this, we propose “DeepCloud” as a novel cloud image feature extraction approach by resorting to the deep convolutional visual features. In the recent years, the deep convolutional neural network (CNN) has achieved the promising results in lots of computer vision and image understanding fields. Nevertheless, it has not been applied to cloud image classification yet. Thus, we actually pay the first effort to fill this blank. Since cloud image classification can be attributed to a multi-instance learning problem, simply employing the convolutional features within CNN cannot achieve the promising result. To address this, Fisher vector encoding is applied to executing the spatial feature aggregation and high-dimensional feature mapping on the raw deep convolutional features. Moreover, the hierarchical convolutional layers are used simultaneously to capture the fine textural characteristics and high-level semantic information in the unified manner. To further leverage the performance, a cloud pattern mining and selection method are also proposed. It targets at finding the discriminative local patterns to better distinguish the different kinds of clouds. The experiments on a challenging ground-based cloud image data set demonstrate the superiority of the proposition over the state-of-the-art methods. Auteurs: Liang Ye;Zhiguo Cao;Yang Xiao; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5729 - 5740 Editeur: IEEE Document complet vers site de l'éditeur
» Defense Mechanisms against Data Injection Attacks in Smart Grid Networks
 Résumé:In the smart grid, bidirectional information exchange among customers, operators, and control devices significantly improves the efficiency of energy supplying and consumption. However, integration of intelligence and cyber systems into a power grid can lead to serious cyber security challenges and makes the overall system more vulnerable to cyber attacks. To address this challenging issue, this article presents defense mechanisms to either protect the system from attackers in advance or detect the existence of data injection attacks to improve the smart grid security. Focusing on signal processing techniques, this article introduces an adaptive scheme on detection of injected bad data at the control center. This scheme takes the power measurements of two sequential data collection slots into account, and detects data injection attacks by monitoring the measurement variations and state changes between the two time slots. The proposed scheme has the capability of adaptively detecting attacks including both non-stealthy attacks and stealthy attacks. Stealthy attacks are proved impossible to detect using conventional residual- based methods, and can cause more dangerous effects on power systems than non-stealthy attacks. It is demonstrated that the proposed scheme can also be used for attack classification to help system operators prioritize their actions to better protect their systems, and is therefore very valuable in practical smart grid systems. Auteurs: Jing Jiang;Yi Qian; Apparue dans: IEEE Communications Magazine Date publication: 10.-2017, volume: 55, issue:10, pages: 76 - 82 Editeur: IEEE Document complet vers site de l'éditeur
» Degradation Effects on Energy Absorption Capability and Time to Failure of Low Voltage Metal Oxide Varistors
 Résumé:Reliability of a surge protection device depends on the health of its protecting elements. Metal oxide Varistors (MOVs) are widely used in electric appliances and power distribution systems. They are known to degrade over time when they experience high-surges and long-duration transients. In this paper, more than 120 MOVs are subjected to nominal 8/20 μs unipolar and bipolar surges of 40 kA in different groups, up to different levels of degradations. Then, they are subjected to energy absorption capability (EAC) tests with ac currents, in a UL-certified lab. Their EAC, peak currents, and time to failures (TtFs) are measured and analyzed. Results show that although degradation due to surges might decrease EAC and TtF of the MOVs in a given current, the average EAC and TtF of degraded MOVs are increased for a certain applied over-voltage. This paper explains the reasons and proposes a model for a degraded MOV that shows a realistic behavior in a transient overvoltage (TOV) condition. Auteurs: Dawood Talebi Khanmiri;Roy Ball;Brad Lehman; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2272 - 2280 Editeur: IEEE Document complet vers site de l'éditeur
» Degrees of Freedom of Full-Duplex Cellular Networks: Effect of Self-Interference
 Résumé:It was recently shown that full-duplex (FD) operation at a base station (BS) can provide up to twice as many degrees of freedom (DoF) as a conventional half-duplex (HD) cellular network in the absence of self-interference. In practice, however, self-interference in an FD BS may not be eliminated completely due to imperfect cancellation, and it is not yet known whether FD operation can improve the sum DoF of cellular networks in the presence of residual self-interference. In this paper, we provide a complete characterization of the sum DoF in an FD-BS cellular network with self-interference, where the rank of the self-interference matrix is arbitrary. Specifically, we propose a self-interference cancellation scheme that maximizes the sum DoF, and we prove its optimality by deriving the matching upper bound. Our results show that even in the presence of residual self-interference, an FD-BS network can still outperform a conventional HD-BS network, and furthermore, the sum DoF coincides with that of an FD-BS network with no self-interference under certain conditions. We also derive an achievable sum rate under ergodic phase fading, showing that not only a sum-DoF gain but also a sum-rate gain can be obtained over the entire signal-to-noise ratio range even if residual self-interference exists. Auteurs: Sung Ho Chae;Kisong Lee; Apparue dans: IEEE Transactions on Communications Date publication: 10.-2017, volume: 65, issue:10, pages: 4507 - 4518 Editeur: IEEE Document complet vers site de l'éditeur
» Delay Properties of Energy Efficient Ethernet Networks
 Résumé:Networking operational costs and environmental concerns have lately driven the quest for energy efficient equipment. In wired networks, energy efficient Ethernet (EEE) interfaces can greatly reduce power demands when compared with regular Ethernet interfaces. Their power saving capabilities have been studied and modeled in many research articles in the last few years, together with their effects on traffic delay. However, to this date, all articles have considered them in isolation instead of as part of a network of EEE interfaces. In this letter, we develop a model for the traffic delay on a network of EEE interfaces. We prove that, whatever the network topology, the per interface delay increment due to the power savings capabilities is bounded and, in most scenarios, negligible. This confirms that EEE interfaces can be used in all but the most delay constrained scenarios to save considerable amounts of power. Auteurs: Miguel Rodríguez-Pérez;Sergio Herrería-Alonso;Manuel Fernández-Veiga;Cándido López-García; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2194 - 2197 Editeur: IEEE Document complet vers site de l'éditeur
» Delay Robustness of an $\mathcal {L}_1$ Adaptive Controller for a Class of Systems With Unknown Matched Nonlinearities
 Résumé:This paper studies the delay robustness of an $\mathcal {L}_1$ adaptive controller designed for systems with unknown matched nonlinearities and unknown input-gain matrices. The analysis establishes rigorously the existence of a positive lower bound for the closed-loop system's time-delay margin (TDM), provided that a filter bandwidth and an adaptive gain are chosen sufficiently large. In this case, if the input delay is below a critical value, then the state and control input of the control system follow those of a nonadaptive, robust reference system closely. The analysis also suggests a way to estimate this lower bound for the delay robustness using Padé approximants. Results from forward simulation are consistent with the Padé estimate and with an explicit upper bound on the TDM which decays to 0 as the filter bandwidth grows without bound. Auteurs: Kim-Doang Nguyen;Yang Li;Harry Dankowicz; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5485 - 5491 Editeur: IEEE Document complet vers site de l'éditeur
» Delivering Real-Time Information Services on Public Transit: A Framework
 Résumé:Public transit is described by a wide range of data, which include sensor data, open data, and social network data. Data come in large real-time streams, and are heterogeneous. How to integrate such data in real time? We propose MOBility ANAlyzer (MOBANA), a distributed stream-based framework. MOBANA deals with the integration of heterogeneous information, processing efficiency, and redundancy reduction. As far as integration is concerned, MOBANA integrates data at different layers, and converts them into exchangeable data formats. Specifically, to integrate feed information, MOBANA uses an improved incremental text classifier, based on Kullback Leibler distance. As far as efficiency is concerned, MOBANA is implemented by distributed stream processing engine and distributed messaging system, which enable scalable, efficient, and reliable real-time processing. Specifically, within the transport domain, MOBANA identifies the real-time position of vehicles by an as-needed adjustment of planned position against the real-time position, thus dropping network load. As far as redundancy is concerned, MOBANA filters tweets through a three-fold similarity analysis, which encompasses geo-location, text, and image. In addition, MOBANA is a complete framework, which has been tested as a pilot with real data in the city of Pavia, Italy. Auteurs: Tianyi Ma;Gianmario Motta;Kaixu Liu; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 10.-2017, volume: 18, issue:10, pages: 2642 - 2656 Editeur: IEEE Document complet vers site de l'éditeur
» DEM Retrieval From Airborne LiDAR Point Clouds in Mountain Areas via Deep Neural Networks
 Résumé:Airborne light detection and ranging (LiDAR) remote sensing enables accurate estimation and monitoring of terrain and vegetation, and digital surface model (DSM) and digital elevation model (DEM) are vital analytical tools to achieve this estimation and monitoring. Among them, DSM can be directly acquired from airborne LiDAR point clouds; nevertheless, for the production of DEM, point clouds representing a surface of ground objects should be accurately filtered out at first. In some mountain forest areas, due to the limited penetration of airborne LiDAR, ground points sustain a serious lack, which results in the difficulty in producing accurate DEMs. To reduce the intricacy and subjectivity caused by the manual supplement to ground points, this letter proposes a new DEM retrieval method from airborne LiDAR point clouds in mountain areas based on deep neural networks (DNNs). With a DNN model trained by accurate DEMs and DSMs, DEM retrieval becomes much easier by inputting their DSM into this model for prediction. Experiments on Fujian and Hainan mountain data sets demonstrate the effectiveness of this supervised method. Auteurs: Yimin Luo;Hongchao Ma;Liguo Zhou; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1770 - 1774 Editeur: IEEE Document complet vers site de l'éditeur
» Demonstration of a Novel Technique for Non-Intrusive In-Band OSNR Derivation Using Flexible Rate Optical Transponders Over a Live 727 km Flexible Grid Optical Link
 Résumé:In high speed optical transmission networks, OSNR is the key optical performance parameter. We propose a novel technique for non-intrusive in-band OSNR derivation based on real-time pre-FEC bit error rate (BER) measurement from optical transponders, which exploits pre-measured and calibrated pre-FEC BER versus OSNR curves and multiple modulation formats to ensure accurate OSNR derivation over a wide range. We report a successful field trial of this novel in-band OSNR technique, in which we have demonstrated and verified the accurate OSNR derivation over both a 359 km field trial link and a live 727 km flexible grid optical link using 64 GBaud flexible rate optical transponders with modulation formats 100G DP-QPSK, 200G DP-16QAM, and 200G DP–QPSK. Compared with standard signal “on” and “off” measurement, an OSNR accuracy within ±1 dB was achieved for all three modulation formats. We also investigated the impact of fiber nonlinearity at different signal powers on the accuracy of this technique. It is shown that this novel technique provides reliable and accurate OSNR derivation for the optical signals operating in normal power regime making it suitable for practical network applications. Auteurs: Yu Rong Zhou;Kevin Smith;John Weatherhead;Paul Weir;Andrew Lord;Jingxin Chen;Weiwei Pan;Daniel Tanasoiu;Shipeng Wu; Apparue dans: Journal of Lightwave Technology Date publication: 10.-2017, volume: 35, issue:20, pages: 4399 - 4405 Editeur: IEEE Document complet vers site de l'éditeur
» DENA: A Configurable Microarchitecture and Design Flow for Biomedical DNA-Based Logic Design
 Résumé:DNA is known as the building block for storing the life codes and transferring the genetic features through the generations. However, it is found that DNA strands can be used for a new type of computation that opens fascinating horizons in computational medicine. Significant contributions are addressed on design of DNA-based logic gates for medical and computational applications but there are serious challenges for designing the medium and large-scale DNA circuits. In this paper, a new microarchitecture and corresponding design flow is proposed to facilitate the design of multistage large-scale DNA logic systems. Feasibility and efficiency of the proposed microarchitecture are evaluated by implementing a full adder and, then, its cascadability is determined by implementing a multistage 8-bit adder. Simulation results show the highlight features of the proposed design style and microarchitecture in terms of the scalability, implementation cost, and signal integrity of the DNA-based logic system compared to the traditional approaches. Auteurs: Zohre Beiki;Ali Jahanian; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 10.-2017, volume: 11, issue:5, pages: 1077 - 1086 Editeur: IEEE Document complet vers site de l'éditeur
» Depth Estimation Using an Infrared Dot Projector and an Infrared Color Stereo Camera
 Résumé:This paper proposes a method of estimating depth from two kinds of stereo images: color stereo images and infrared stereo images. An infrared dot pattern is projected on a scene by a projector so that infrared cameras can capture the scene textured by the dots and the depth can be estimated even where the surface is not textured. The cost volumes are calculated for the infrared and color stereo images for each frame and are extended in the time direction to define a spatiotemporal cost volume (st-cost volume). We also extend the cost volume filter in the time direction by modifying the cross-based local multipoint filter (CLMF) and applying it to the st-cost volumes in order to restrain flicker on the time-varying depth maps. To get a reliable cost volume, the infrared and color st-cost volumes are integrated into a single cost volume by selecting the cost of either the infrared or the color st-cost volumes according to the size of the adaptive kernel used for the CLMF. Then, a graphcut is executed on the cost volume in order to estimate the disparity robustly even when the baselines of the stereo cameras are set wide enough to ensure spatially high resolution in the depth direction and the shapes of blocks are deformed by the affine transformation. A 2D graphcut is executed on each scan line to reduce the processing time and memory consumption. We experimented with the proposed method using infrared color stereo data sets of scenes in the real world and evaluated its effectiveness by comparing it with other recent stereo matching methods and depth cameras. Auteurs: Kensuke Hisatomi;Masanori Kano;Kensuke Ikeya;Miwa Katayama;Tomoyuki Mishina;Yuichi Iwadate;Kiyoharu Aizawa; Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology Date publication: 10.-2017, volume: 27, issue:10, pages: 2086 - 2097 Editeur: IEEE Document complet vers site de l'éditeur
» Deriving Bisimulation Relations from Path Extension Based Equivalence Checkers
 Résumé:Constructing bisimulation relations between programs as a means of translation validation has been an active field of study. The problem is in general undecidable. Currently available mechanisms suffer from drawbacks such as non-termination and significant restrictions on the structures of programs to be checked. We have developed a path extension based equivalence checking method as an alternative translation validation technique to alleviate these drawbacks. In this work, path extension based equivalence checking of programs (flowcharts) is leveraged to establish a bisimulation relation between a program and its translated version by constructing the relation from the outputs of the equivalence checker. Auteurs: Kunal Banerjee;Dipankar Sarkar;Chittaranjan Mandal; Apparue dans: IEEE Transactions on Software Engineering Date publication: 10.-2017, volume: 43, issue:10, pages: 946 - 953 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Analysis of a 1.8-GHz Open-Loop Modulator for Phase Modulation and Frequency Synthesis Using TDC-Based Calibration
 Résumé:A nonlinearity calibration technique is proposed for an open-loop phase modulator (PM), for wideband phase modulation, and for multiple-output, low-jitter clock generation. The design considerations and key performance aspects of the calibration technique are discussed. The PM integrates a digital phase-locked loop, local oscillator distribution network, and digital calibration. A prototype was implemented in 0.13- $\mu \text{m}$ CMOS 1.8-GHz Gaussian frequency shift keying (GFSK) transmitter integrated circuit. Measurements on the prototype show that out-of-band quantization noise is 56 dB lower than that of the signal when transmitting 20-Mb/s GFSK signal and the rms error is only 3.2%. The power consumption of the PM is 18 mW. The measured spurious tones of the clock generation unit are below −46 dBc. Auteurs: Nitin Nidhi;Sudhakar Pamarti; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3975 - 3988 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Analysis of a Bistable Vibration Energy Harvester Using Diamagnetic Levitation Mechanism
 Résumé:In this paper, a novel bistable vibration energy harvester using the diamagnetic levitation mechanism is conceptualized, designed, fabricated, and experimented comprehensively. The bistable energy harvester consists of a floating magnet, lifting magnets, diamagnetic plates, and coils. The lifting magnets placed symmetrically on the both sides of the base are designed to balance the weight of the floating magnet and produce a bistable potential well. The floating magnet is stabilized in the horizontal direction by diamagnetic plates which are made of pyrolytic graphite. Ring-shaped coils are designed for transduction and flanked by the side of diamagnetic plates. Theoretical modeling and analyses are carried out to compare with experimental data. Throughout the theoretical and experimental results, a peak power of $333.7~\mu \text{w}$ is generated from a vibration level of 0.6 m/ $\text{s}^{2}$ over a range of 0.5–4.5 Hz. It is indicated that the bistable energy harvester can efficiently operate at extremely low frequencies (<5 Hz). Auteurs: Qiu-Hua Gao;Wen-Ming Zhang;Hong-Xiang Zou;Wen-Bo Li;Zhi-Ke Peng;Guang Meng; Apparue dans: IEEE Transactions on Magnetics Date publication: 10.-2017, volume: 53, issue:10, pages: 1 - 9 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Analysis of a Higher Order Power Filter for Grid-Connected Renewable Energy Systems
 Résumé:Harmonic compensation is regularly implemented for a grid-tied inverter to reduce the influence of the grid current and voltage harmonics. In this study, the L(LCL)$_{2}$ filter, which is a high-order power filter for single-phase grid-tied voltage-source inverters, is designed and analyzed. In order to attenuate the high-frequency harmonics, additional resonant branch at the double of the switching frequency is added to the LLCL filter. The total inductance of this filter is almost less than the LLCL filter with the amount of the grid-side inductor. A comparative study on filter parameter design, size estimation, efficiency, stability, and dc-link dynamics in bidirectional power flow applications between the LLCL filter and the proposed L(LCL) $_{2}$ filter has been conducted. The assessment of these studies is presented through both experimental hardware implementation and MATLAB/Simulink-based simulation on a 700 W, 120 V/60 Hz single-phase grid-tied inverter. It is concluded that, compared with the LLCL filter, the L(LCL)$_{2}$ filter not only has less voltage drop and total component size, but also has better performance on reducing high-order current harmonics. Additionally, the L(LCL)$_{2}$ filter has a smaller size, less losses, stable closed-loop control system, and compared with traditional LLCL filter, it does not add any control difficulty to the system. Auteurs: Arash Anzalchi;Masood Moghaddami;Amir Moghadasi;Maneli Malek Pour;Arif I. Sarwat; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4149 - 4161 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Analysis of a Hybrid Radio Frequency and Visible Light Communication System
 Résumé:In this paper, a hybrid radio frequency (RF) and visible light communication (VLC) system is considered. A hybrid system with multiple VLC access points (APs) and RF APs is designed and analyzed. In indoor environments, VLC APs provide very high data rates whilst proving illumination, and RF APs offer ubiquitous coverage with moderate data rates. Since VLC networks piggyback on existing lighting infrastructures, they may not always be able to provide full coverage despite supporting very high data rates in some areas. Hence in practical deployments, the standalone VLC networks should be augmented in order to improve the per user data rate coverage. In this context, RF APs can be used to improve the per user rate coverage of VLC networks as well as to provide the ubiquitous control functionalities. In this paper, a simple RF deployment is proposed in order to improve the per user outage data rate performance of standalone VLC networks. It is assumed that the VLC system resources are fixed, and this paper quantifies the minimum spectrum and power requirements for a RF system, which after introduction to the VLC system, the hybrid RF/VLC system achieves certain per user rate coverage performances. Auteurs: Dushyantha A. Basnayaka;Harald Haas; Apparue dans: IEEE Transactions on Communications Date publication: 10.-2017, volume: 65, issue:10, pages: 4334 - 4347 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Analysis of a Wideband Gilbert Cell VGA in 0.25- $\mu {\rm m}$ InP DHBT Technology With DC-40-GHz Frequency Response
 Résumé:A differential variable gain amplifier (VGA) for wideband baseband signals has been designed, analyzed, and implemented in a 0.25- $\rm \mu m$ InP double heterojunction bipolar transistor technology with $f_{T}/f_{\mathrm{ max}}$ of 370/650 GHz. The 3-dB frequency bandwidth is measured to be 40 GHz with a maximum gain of 31 dB, resulting in a gain bandwidth product (GBP) of 1.4 THz, four times higher than previously reported GBP from a Gilbert cell-based VGAs. Furthermore, it measures a gain control range of 44 dB, a noise figure of 6.2 dB, an output third-order intercept point of 17 dBm, and a total power consumption of 350 mW from a single −7-V supply. With pseudorandom binary sequence test pattern signals, a clear open eye at 44 Gb/s was observed. The complete circuit, including on-chip integrated bias network and pads, measures 0.77 $\rm mm^{2}$ . We analyze the VGA for the 3-dB bandwidth and GBP by the use of zero-value time constants method to analytically identify the maximum GBP with respect to the design parameters and current bias. Auteurs: Marcus Gavell;Sten E. Gunnarsson;Iltcho Angelov;Zhongxia Simon He;Mattias Ferndahl;Herbert Zirath; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3962 - 3974 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Analysis of Initial Access in Millimeter Wave Cellular Networks
 Résumé:Initial access is the process which allows a mobile user to first connect to a cellular network. It consists of two main steps: cell search (CS) on the downlink and random access (RA) on the uplink. Millimeter wave (mm-wave) cellular systems typically must rely on directional beamforming (BF) in order to create a viable connection. The BF direction must, therefore, be learned—as well as used—in the initial access process for mm-wave cellular networks. This paper considers four simple but representative initial access protocols that use various combinations of directional BF and omnidirectional transmission and reception at the mobile and the BS, during the CS and RA phases. We provide a system-level analysis of the success probability for CS and RA for each one, as well as of the initial access delay and user-perceived downlink throughput (UPT). For a baseline exhaustive search protocol, we find the optimal BS beamwidth and observe that in terms of initial access delay it is decreasing as blockage becomes more severe, but is relatively constant (about $\pi /12$ ) for UPT. Of the considered protocols, the best tradeoff between initial access delay and UPT is achieved under a fast CS protocol. Auteurs: Yingzhe Li;Jeffrey G. Andrews;François Baccelli;Thomas D. Novlan;Charlie Jianzhong Zhang; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6409 - 6425 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Assessment of a 2.5-Gb/s Optical Wireless Transmission System for High Energy Physics
 Résumé:We designed, realized, and tested a 2.5-Gb/s optical wireless communication (OWC) system prototype, that should be employed in high energy physics (HEP) experiments, such as the compact muon solenoid (CMS). The system consists of off-the-shelf components, mainly a vertical cavity surface emitting laser (VCSEL) and a PIN photodiode with a proper ball lens. Since it should be used to transmit data among particle sensors in neighboring rings of the CMS, its target distance is 10 cm. Its most attractive feature is that it does not require a (complex) active tracking system because its measured tolerance to misalignment is around $\pm$ 1 mm (at $10^{-12}$ bit error rate). We also report the X-rays irradiation tests of all components (Quartz lens, VCSEL, and PIN photodiode): None of them showed any degradation up till 238-Mrad (Si) dose. These results indicate that the designed OWC can be a viable solution for future HEP experiments. Auteurs: W. Ali;G. Cossu;A. Sturniolo;R. Dell’Orso;A. Messineo;F. Palla;E. Ciaramella; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Characterization of an Exoskeleton for Perturbing the Knee During Gait
 Résumé:Objective: An improved understanding of mechanical impedance modulation in human joints would provide insights about the neuromechanics underlying functional movements. Experimental estimation of impedance requires specialized tools with highly reproducible perturbation dynamics and reliable measurement capabilities. This paper presents the design and mechanical characterization of the ETH Knee Perturbator: an actuated exoskeleton for perturbing the knee during gait. Methods: A novel wearable perturbation device was developed based on specific experimental objectives. Bench-top tests validated the device's torque limiting capability and characterized the time delays of the on-board clutch. Further tests demonstrated the device's ability to perform system identification on passive loads with static initial conditions. Finally, the ability of the device to consistently perturb human gait was evaluated through a pilot study on three unimpaired subjects. Results: The ETH Knee Perturbator is capable of identifying mass-spring systems within 15% accuracy, accounting for over 95% of the variance in the observed torque in 10 out of 16 cases. Five-degree extension and flexion perturbations were executed on human subjects with an onset timing precision of 2.52% of swing phase duration and a rise time of 36.5 ms. Conclusion: The ETH Knee Perturbator can deliver safe, precisely timed, and controlled perturbations, which is a prerequisite for the estimation of knee joint impedance during gait. Significance: Tools such as this can enhance models of neuromuscular control, which may improve rehabilitative outcomes following impairments affecting gait and advance the design and control of assistive devices. Auteurs: Michael R. Tucker;Camila Shirota;Olivier Lambercy;James S. Sulzer;Roger Gassert; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 10.-2017, volume: 64, issue:10, pages: 2331 - 2343 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Characterization of High $di/dt$ CS-MCT for Pulse Power Applications
 Résumé:A high di/dt MOS-controlled thyristor with cathode-short structure (CS-MCT) is developed for pulse power applications. Compared with conventional MCT (con-MCT), the cathode short in the proposed CS-MCT greatly improves the dV/dt robustness. To achieve simultaneously high di/dt capability, special design of device characteristics parameter and consideration of 2-D transient carrier transport are carried out for the first time. Experimental results show that the proposed CS-MCT exhibits di/dt over 357 kA/cm $^{{\textsf {2}}}$ / $\mu \text{s}$ and peak current of 27.1 kA/cm $^{{\textsf {2}}}$ . Meanwhile, the improved practical dV/dt characteristics are validated in comparison with con-MCT at the same condition. The high di/dt property and simultaneously high dV/dt robustness indicate the proposed CS-MCT is a promising semiconductor pulse switch for pulse power applications. Auteurs: Wanjun Chen;Chao Liu;Yijun Shi;Yawei Liu;Hong Tao;Chengfang Liu;Qi Zhou;Zhaoji Li;Bo Zhang; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4206 - 4212 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Control of a High-Power Low-Loss DC–DC Converter for Mining Applications
 Résumé:This paper proposes a new design procedure for a bidirectional dc/dc LCL converter for potential megawatt range applications, including mobile mining equipment. This type of dc/dc converters employ two dc/ac converters and a passive LCL filter instead of a traditional high-frequency transformer. The exclusion of the transformer eliminates the core losses, while the switching losses are minimized by using soft switching operation. The proposed design method is different from previous publications as it ensures zero reactive power circulation, minimizes the size of the biggest capacitor, ensures stable and robust operation, and offers a good tradeoff between the capacitor size and the fault current in the converter under a dc fault condition. In addition to the proposed design, a simple and effective control strategy is proposed, which is based on single phase $pq$ theory. The converter design and control have been evaluated by a digital simulation in EMTP-RV software environment for a 100 MW 300 kV/20 kV converter. Experimental validation has been carried out on a laboratory 200W 100V/20V prototype converter. Auteurs: Mohsen Ghaffarpour Jahromi;Galina Mirzaeva;Steven D. Mitchell; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 5105 - 5114 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Decoupled Compensation Methods of a PM Motor Capable of 6-D Force/Torque Actuation for Minimum Bearing Reaction
 Résumé:This paper presents a methodology to design and control a permanent magnet (PM) motor capable of 6-D force/torque actuation for real-time compensation of external loads to achieve minimum bearing reaction (MBR). Unlike conventional multiphase designs, the current inputs to the stator-electromagnets (EMs) can be flexibly configured to enable 6-D force and/or torque actuation in one motor; two common motor structures (radial and axial types) are illustrated. Both the forward and inverse force/torque models are presented in terms of coordinate-independent kernel functions that characterize the force between an EM and a PM pole pair. Two closed-form solutions to the inverse model that solves for the current-input vector minimizing the total input energy to generate a desired force/torque vector, which can be computed within 1 ms, are derived and verified numerically. A feedforward MBR compensator designed to argument the proportional-integral-derivative (PID) speed regulator has been experimentally evaluated on a structurally smart spindle system to minimize bearing reactions. Experiments show that the MBR compensation effectively reduces vibrations and improves cutting quality. Auteurs: Kun Bai;Kok-Meng Lee;Jun Cao;Ruoyu Xu;Lei Li; Apparue dans: IEEE/ASME Transactions on Mechatronics Date publication: 10.-2017, volume: 22, issue:5, pages: 2252 - 2264 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Deployment of a Wireless Sensor Network for the Mar Menor Coastal Observation System
 Résumé:The Coastal Ocean Observation System of Murcia Region (OOCMUR) was established in 2008 as a major scientific and technological infrastructure in Spain with the main objective of studying the impact of global climate change in the Mediterranean. The coastal lagoon of Mar Menor in southeast Spain was chosen as the first region to be monitored because it is one of the most hypersaline coastal lagoons in the Mediterranean, with a limited exchange of water with the open sea, and it is the largest in Europe. Wireless sensor networks (WSNs) offer an efficient and innovative solution for oceanographic monitoring, allowing a higher density sensor deployment, at a lower cost. This paper presents the design of an ad hoc WSN system and a control software for Mar Menor monitoring using a buoy structure with sensors, energy harvesting, and communications platform. The study focuses on the oceanographic interest of the selected marine area, details of network deployment, the custom-designed sensor nodes, and the results of system operation. Auteurs: Cristina Albaladejo Pérez;Fulgencio Soto Valles;Roque Torres Sánchez;Manuel Jiménez Buendía;Francisco López-Castejón;Javier Gilabert Cervera; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 966 - 976 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Deployment of Special Protection System for Kinmen Power System in Taiwan
 Résumé:If an extreme contingency strikes the Kinmen Island power system in Taiwan, it is very likely to cause blackouts. Although an underfrequency protection scheme has been applied, some drawbacks of the protection scheme hinder the Kinmen power system from avoiding blackouts. In the past decade, several blackouts have occurred in the Kinmen power system. To avoid further possible blackouts, a special protection system (SPS) is summoned. This paper describes the design guidelines and deployment procedures of an SPS for the Kinmen power system. The design depends on the Kinmen power system characteristics, and the deployment hinges upon the supervisory control and data acquisition system. Exquisite software was also developed to testify the Kinmen system SPS. Operational records have demonstrated that the proposed SPS can indeed prevent blackouts from occurring in the Kinmen power system. The design, implementation, and operation of the SPS dealt with in this paper might foster further deployments of other SPSs. Auteurs: Jin-Shyr Yang;Ching-Jung Liao;Yung-Fu Wang;Chia-Chi Chu;Sheng-Huei Lee;Yu-Jen Lin; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4176 - 4185 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Evaluation of a Haptic Interface With Octopod Kinematics
 Résumé:The study of human motor control using functional magnetic resonance imaging gives rise to many challenges. One of them is the design of haptic interfaces that are compatible with the magnetic field. To achieve this, the existing haptic interfaces employ parallel kinematics. However, they are limited to three degrees of freedom (DOFs). When trying to offer more DOF without floating actuators, parallel kinematics suffer from direct kinematic singularities, and thus, strong mechanical anisotropy. In this paper, we determine an optimal six DOF kinematics that overcomes these limitations. To this end, we use performance indices such as singularity occurrence, worst case output capabilities, sensitivity, and the global isotropy index. The resulting Octopod kinematics avoids a range of direct kinematic singularities by design. Finally, we pre-sent and evaluate a non-magnetic-resonance-compatible prototype of this novel type of kinematics. Auteurs: Markus Kühne;Johannes Potzy;Roberto García-Rochín;Patrick van der Smagt;Angelika Peer; Apparue dans: IEEE/ASME Transactions on Mechatronics Date publication: 10.-2017, volume: 22, issue:5, pages: 2091 - 2101 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Implementation of Disturbance Compensation-Based Enhanced Robust Finite Control Set Predictive Torque Control for Induction Motor Systems
 Résumé:Finite-control-set-based predictive torque control (PTC) method has received more and more attention in recent years due to its fast torque response. However, it also has two drawbacks that could be improved. First, the torque reference in the cost function of the existing PTC method is generated by the proportional–integral speed controller, so torque reference's generation rate is not fast and its accuracy is low especially when the load torque is given suddenly and inertia value is varying. In addition, the variable prediction of the traditional PTC method depends on the system model, which also has the problem of parameter uncertainties. This paper investigates a disturbance observer (DOB)-based PTC approach for induction motor systems subject to load torque disturbances, parameter uncertainties, and time delays. Not only does the speed loop adopt a DOB-based feed-forward compensation method for improving the system disturbance rejection ability and robustness, but the flux, current, and torque predictions are also improved by using this technique. The simulation and experimental results verified the effectiveness of the proposed method. Auteurs: Junxiao Wang;Fengxiang Wang;Zhenbin Zhang;Shihua Li;José Rodríguez; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2645 - 2656 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Manufacture of Cosecant-Squared Complementary Reflectarrays for Low-Cost Applications
 Résumé:A novel solution for the manufacturing of a reflectarray antenna with cosecant-squared radiation pattern is presented. The unit cell simply consists of a 3-D printed nylon grid inserted in between two thick metallic plates. To introduce the required phase delay, C and reverse C slots are laser cut into the plate illuminated by the feeder. This solution allows obtaining an efficient, robust, and compact antenna with low-cost manufacturing process, even for no mass production. Measurements confirm the feasibility of the proposed solution and show its performances. Auteurs: Giorgio Carluccio;Agnese Mazzinghi;Angelo Freni; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5220 - 5227 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Performance Investigation of Novel Linear Switched Flux PM Machines
 Résumé:A novel partitioned primary linear switched flux permanent magnet (PLSFPM) machine is presented, which adopts an odd number of primary poles. For the design objective of minimum thrust ripple, the optimized novel PLSFPM machine with 9 primary/10 secondary (9/10) pole combination is obtained. To this optimized PLSFPM machine, the electromagnetic performance is analyzed in detail and compared with that of the original one. The merits of this 9/10 pole combination are also proved by comparative study with other three available pole combinations. Moreover, comparison between the proposed PLSFPM machine and a conventional linear switched flux permanent magnet machine has been performed, which shows that the proposed machine can achieve better performances under both open-circuit and load conditions. The corresponding prototype is manufactured and the influences of possible machining errors during manufacture on thrust force performance are discussed. Finally, the experiment is carried out, which verifies the predicted results. The research shows that the proposed PLSFPM machine with 9/10 pole combination has high thrust force and low thrust ripple. Auteurs: Qinfen Lu;Yihua Yao;Jiameng Shi;Yiming Shen;Xiaoyan Huang;Youtong Fang; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4590 - 4602 Editeur: IEEE Document complet vers site de l'éditeur
» Design and Prototyping a Smart Deep Brain Stimulator: An Autonomous Neuro-Sensing and Stimulating Electrode System
 Résumé:This article presents the design and prototyping of an innovative smart deep brain stimulator (SDBS) that consists of brain-implantable smart electrodes and a wireless-connected external controller. SDBS electrodes operate as completely autonomous electronic implants that are capable of sensing and recording neural activities in real time, performing local processing, and generating arbitrary waveforms for neuro-stimulation. A bidirectional, secure, fully passive wireless communication backbone was designed and integrated into this smart electrode to maintain contact between the electrodes and the controller. The standard EPC-Global protocol has been modified and adopted as the communication protocol in this design. The proposed SDBS was demonstrated and tested through a hardware prototypes. Auteurs: Muhammad S. Khan;Hai Deng; Apparue dans: IEEE Intelligent Systems Date publication: 10.-2017, volume: 32, issue:5, pages: 14 - 27 Editeur: IEEE Document complet vers site de l'éditeur
» Design Approach to a Novel Dual-Mode Wideband Circular Sector Patch Antenna
 Résumé:A design approach to a novel wideband circular sector patch antenna is proposed. Design guidelines are laid down based on an approximate 1.5-wavelength, multimode magnetic dipole, and the cavity model. Then, the flared angle of the circular sector patch and the corresponding usable resonant modes for wideband radiation are determined. It is demonstrated that the resonant TM4/3,1 and the TM8/3,1 modes within a 270° circular sector patch radiator can be simultaneously excited, perturbed, and employed to form a wideband unidirectional radiation characteristic with two resonances. Prototype antennas are designed and fabricated to experimentally validate the dual-resonant wideband property on a single-layered substrate. It is further demonstrated that the antenna designed on a 5-mm-thick air substrate exhibits an available radiation bandwidth (ARB) of 14.5%, while the printed one designed on a 2-mm-thick modified Teflon substrate exhibits an ARB of 6.5%. It is evidently validated that the proposed approach can be employed to effectively enhance the operational bandwidth of microstrip patch antennas without increasing antenna profile, inquiring multiple radiators or employing reactance compensation techniques. Auteurs: Wen-Jun Lu;Qing Li;Sheng-Guang Wang;Lei Zhu; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 4980 - 4990 Editeur: IEEE Document complet vers site de l'éditeur
» Design for Manufacturability of an Off-Shore Direct-Drive Wind Generator: An Insight Into Additional Loss Prediction and Mitigation
 Résumé:Direct-drive generators to be used in off-shore wind farms are very large low-speed electric machines, which pose remarkable design and manufacturing challenges. Demand forecasts for this kind of machines are urging manufacturers to work out design and technological solutions capable of facilitating series production at competitive costs. This paper presents the development of an interior permanent-magnet generator design and technology aimed at reducing series manufacturing costs while preserving good performance levels. The focus is on two of the most critical issues in the machine design and analysis, namely, the prediction and reduction of eddy-current losses in stator conductors and in permanent magnets. The proposed design solutions are validated through the construction and testing of a 780 kVA generator prototype conceived for easy scalability to higher power ratings (up to around 2.5 MVA) by core length increase. Auteurs: Alberto Tessarolo;Fabio Luise;Stefano Pieri;Andrea Benedetti;Mauro Bortolozzi;Matteo De Martin; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4831 - 4842 Editeur: IEEE Document complet vers site de l'éditeur
» Design Method for Multiband WPDs Using Multisection $LC$ -Ladder Circuits
 Résumé:This letter describes a design method for multiband Wilkinson power dividers (WPDs) utilizing multisection $LC$ -ladder circuits. The design method is inspired by even-and odd-mode analysis techniques and an $L$ -section matching network. Two trial dividers, which operate with dual-band/triband, were fabricated at a 300-MHz band. The measured relative bandwidths of these dividers were more than 45% and 60%, and their insertion losses were less than 1 dB. The sizes of these WPDs were $17.0\times13.3$ mm2 and $22.0\times14.3$ mm2, respectively. The measurement results for the fabricated dividers were in good agreement with theoretical results and the dividers show multiband characteristics. Auteurs: Yosuke Okada;Tadashi Kawai;Akira Enokihara; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 894 - 896 Editeur: IEEE Document complet vers site de l'éditeur
» Design of 3-dB Hybrid Coupler Based on RGW Technology
 Résumé:Hybrid couplers are essential devices in various microwave circuits and systems, such as radar systems and beam forming networks. The development of this device is necessary along with the development of the new communication standards for the most modern guiding structures. One of the most recent and promising guiding technologies is the ridge gap waveguides, which is expected to play an essential role in the millimeter wave and submillimeter wave applications, not only the 5G communications but also other future communication. Therefore, standards are recommended to make use of the high-frequency guiding structures. In this paper, a design procedure for the hybrid couplers is presented. The frequency band of interest is centered at the 15 GHz, which can be deployed for both the 5G mobile communication and the airborne radar applications. The proposed design is fabricated and measured. The measured and simulated results are in excellent agreement. Auteurs: Shoukry I. Shams;Ahmed A. Kishk; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3849 - 3855 Editeur: IEEE Document complet vers site de l'éditeur
» Design of a 6-MW Solid-State Pulse Modulator Using Marx Generator for the Medical Linac
 Résumé:The linear accelerators (linacs) producing high energy and high power of electron-beam or X-ray beam have been used in medicine, industry, national security, etc. In the linac, the electrons are generated by the electron gun and accelerated in the accelerating column with the high-power RF fields. The high-voltage pulses from the pulse modulator are supplied to the RF power source and the electron gun. The pulse modulator is one of the big and expensive components in the linac. The commercial medical linacs commonly use the pulse modulator based on the thyratron-switched pulse-forming network. In order to improve the power efficiency, achieve the system compactness, and optimize the cost and space, the solid-state pulse modulator based on the Marx generator was proposed. The low-power solid-state pulse modulator was developed for the electron gun operation. The conceptual design and functional results were confirmed. In order to apply it to the RF power source, such as a magnetron or a klystron, the 6-MW pulse modulator with the same Marx scheme is proposed. It consists of 40 storage-switch stages and one high-voltage pulse transformer, producing the pulse of 50 kV and 120 A required by the magnetron in the medical linac. A storage-switch stage was designed for insulated gate bipolar transistors to switch high current of 280 A and 720 V and to use the capacitor of $25~\mu \text{F}$ which was chosen for the voltage droop of 10% with the pulsewidth of $5~\mu \text{s}$ . The prototype system with eight storage-switch stages was fabricated and tested with a load system. The performance results show that it can be extended to be the 6-MW solid-state pulse modulator. In this paper, we describe the design features, and discuss the results and also the future plan to optimize the solid-state pulse modulator - n the medical linac. Auteurs: Heuijin Lim;Dong Hyeok Jeong;Manwoo Lee;Sung Chae Ro; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2734 - 2738 Editeur: IEEE Document complet vers site de l'éditeur
» Design of a Compact Pneumatic Power Generator With a Self-Regulating Mechanism for Mobile Application
 Résumé:The pneumatic actuator has high potential as an actuator for mobile devices due to its high power density, simplicity, compactness, light weight, and low cost. Moreover, inherent compliance of the pneumatic actuator improves safety and dynamic performance, which are strongly required for wearable robots. However, due to its need for a bulky air compressor, which is intended for stationary use, it is hard to apply a pneumatic actuator to mobile robots. To replace the air compressor, pneumatic energy sources utilizing chemical fuel were previously proposed and the potential of the hydrogen peroxide as a pneumatic energy source was proved. Nevertheless, pneumatic energy sources driven by hydrogen peroxide are generally bulky, which are hard to apply for a mesoscale system such as prosthetics. To address this challenge, this paper proposes novel pneumatic power generator driven by hydrogen peroxide. By applying a passive injection component and a mechanical pressure feedback mechanism, the pneumatic power generator regulates pressure by itself, without any control efforts, which results in compact size. In addition, a separated catalytic reactor and a fuel tank guarantee safety and mobility. The performances and energetic characteristics of the proposed pneumatic power generator are examined by both experiment and mathematical modeling. Auteurs: Kyung-Rok Kim;Yun-Pyo Hong;Kyung-Soo Kim;Soohyun Kim; Apparue dans: IEEE/ASME Transactions on Mechatronics Date publication: 10.-2017, volume: 22, issue:5, pages: 1983 - 1991 Editeur: IEEE Document complet vers site de l'éditeur
» Design of a High-Speed Ferrite-Based Brushless DC Machine for Electric Vehicles
 Résumé:In this paper an analytical procedure for the preliminary design of a high-speed ferrite-based brushless dc machine (HS-BLDC) has been proposed. In particular, mechanical and electromagnetic modeling have been developed in order to take into account their mutual influence in the definition of the geometry of the electrical machine. In addition, suitable design targets have been imposed in accordance with electric vehicle application requirements. Hence, several mechanical and electromagnetic constraints have been introduced in order to comply with high-speed operation, preventing demagnetization issues of ferrite magnets as well. Subsequently, an HS-BLDC characterized by an inner rotor configuration has been designed in accordance with the proposed methodology. The analytical procedure and the corresponding results have been reported and validated by means of finite element analyses, highlighting the effectiveness of the proposed configuration and design solutions. Auteurs: Alfonso Damiano;Andrea Floris;Giuseppe Fois;Ignazio Marongiu;Mario Porru;Alessandro Serpi; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4279 - 4287 Editeur: IEEE Document complet vers site de l'éditeur
» Design of A Novel Highly EMI-Immune CMOS Miller OpAmp Considering Channel Length Modulation
 Résumé:This paper presents a novel CMOS Miller operational amplifier (OpAmp) that has high immunity to electromagnetic interference (EMI). The proposed CMOS Miller OpAmp uses the replica concept with the source-buffered technique in order to achieve high EMI immunity across a wide range of frequencies (10 MHz to 1 GHz). The proposed amplifier is designed using the first-order quadratic mathematical model. The modeling includes the body effect and channel length modulation. The circuit has been fabricated using 0.18 $\mu \text{m}$ mixed-mode CMOS technology. Measurement results illustrate how the proposed Miller OpAmp reduces susceptibility to EMI even in the presence of high-amplitude interferences that are as high as 1 Vpp. Experimental results show that the maximum EMI-induced output offset voltage for the proposed Miller OpAmp is less than 10 mV over a wide range of frequencies (10 MHz to 1 GHz) when a 900 mVpp EMI signal is injected into the noninverting input. In contrast, the classic Miller OpAmp generates a maximum output offset voltage of 215 mV at 1 GHz under the same operating conditions. The measured results of the EMI-induced input offset corroborates the circuit simulations. Auteurs: Subrahmanyam Boyapati;Jean-Michel Redouté;Maryam Shojaei Baghini; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2679 - 2690 Editeur: IEEE Document complet vers site de l'éditeur
» Design of a Parallel Actuated Exoskeleton for Adaptive and Safe Robotic Shoulder Rehabilitation
 Résumé:Powered exoskeletons can facilitate after-stroke rehabilitation of patients with shoulder disabilities. Designs using serial mechanisms usually result in complicated and bulky exoskeletons. This paper presents a new parallel actuated shoulder exoskeleton that consists of two spherical mechanisms, two slider crank mechanisms, and a gravity balancing mechanism. The actuators are grounded and placed side-by-side. Thus, better inertia properties can be achieved while lightweight and compactness are maintained. An adaptive mechanism with only passive joints is introduced to compensate for the exoskeleton–limb misalignment and size variation among different subjects. Linear series elastic actuators (SEAs) are proposed to obtain accurate force and impedance control at the exoskeleton–limb interface. The total number of force sensors and actuators is minimized using the adaptive mechanism and SEAs. An exoskeleton prototype is shown to provide bidirectional actuation between the exoskeleton and upper limb, which is required for various rehabilitation processes. We expect this design can provide a means of shoulder rehabilitation. Auteurs: Hsiang-Chien Hsieh;Dian-Fu Chen;Li Chien;Chao-Chieh Lan; Apparue dans: IEEE/ASME Transactions on Mechatronics Date publication: 10.-2017, volume: 22, issue:5, pages: 2034 - 2045 Editeur: IEEE Document complet vers site de l'éditeur
» Design of Contract-Based Trading Mechanism for a Small-Cell Caching System
 Résumé:Recently, content-aware-enabled distributed cach- ing relying on local small-cell base stations (SBSs), namely, small-cell caching, has been intensively studied for reducing transmission latency as well as alleviating the traffic load over backhaul channels. In this paper, we consider a commercialized small-cell caching system consisting of a network service provider (NSP), several content providers (CPs), and multiple mobile users (MUs). The NSP, as a network facility monopolist in charge of the SBSs, leases its resources to the CPs for gaining profits. At the same time, the CPs are intended to rent the SBSs for providing better downloading services to the MUs. We focus on solving the profit maximization problem for the NSP within the framework of contract theory. To be specific, we first formulate the utility functions of the NSP and the CPs by modeling the MUs and SBSs as two independent Poisson point processes. Then, we develop the optimal contract problem for an information asymmetric scenario, where the NSP only knows the distribution of CPs’ popularity among the MUs. Also, we derive the necessary and sufficient conditions of feasible contracts. Lastly, the optimal contract solutions are proposed with different CPs’ popularity parameter $\gamma$ . Numerical results are provided to show the optimal quality and the optimal price designed for each CP. In addition, we find that the proposed contract-based mechanism is superior to the benchmarks from the perspective of maximizing the NSP’s profit. Auteurs: Tingting Liu;Jun Li;Feng Shu;Meixia Tao;Wen Chen;Zhu Han; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6602 - 6617 Editeur: IEEE Document complet vers site de l'éditeur
» Design of Dual Purpose No-Voltage Combined Windings for Bearingless Motors
 Résumé:A winding design approach is proposed to create a single motor winding, which is able to produce both radial force and torque. This approach can be used to design new bearingless motors, as well as to transform conventional motor designs into bearingless motors by simply modifying the winding end connections. The resulting winding has two sets of terminal connections, one for torque and one for suspension. The suspension terminals experience no motional-electromotive force when the rotor is centered, which means that the suspension drive can have a low voltage rating and that rotor vibrations can be passively dampened by simply short-circuiting the suspension terminals. Bearingless motors that use these so-called dual purpose no voltage windings can be designed to have higher torque density and lower losses associated with the magnetic suspension operation than traditional bearingless motors, which utilize separate torque and suspension windings. It will be shown that many popular winding designs, including fractional-slot and concentrated windings, can be realized as dual purpose no-voltage windings. The proposed approach applies to traditional $p\pm 1$ pole-pair bearingless motors, as well as the bearingless consequent-pole and ac homopolar motors. Fractional-slot motor winding theory is used to derive the new winding requirements and a generalized design procedure; example designs are explored through finite element analysis and experimental results from a hardware prototype of a bearingless ac homopolar motor. Auteurs: Eric Loren Severson;Robert Nilssen;Tore Undeland;Ned Mohan; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4368 - 4379 Editeur: IEEE Document complet vers site de l'éditeur
» Design of Dynamic Wavelet Packet Division Multiplexing
 Résumé:At the reception of wireless communications the wavelet packet-division multiplexing (WPDM) has shown susceptibility to multipath fading. Inspired by WPDM, this paper proposes a new scheme of multiplexing, which has been called “Dynamic Wavelet Packet-Division Multiplexing (DWPDM)”, that allow adapt to the channel conditions and improve their performance both in time-variant as time-invariant channels. The proposed scheme also allow increase the quality of service and improve the security of transmission of binary message thanks to the random variation in the time of the carries or wavelet packet functions. The scheme were evaluated by simulation in three communication scenarios: AWGN channel, selective fading channel and slowly-varying notch channel, showing improvement compared with WPDM, Branch-Hopped WPDM and WOFDM. Auteurs: Juan Pablo Hoyos Sanchez;Pablo Emilio Jojoa Gomez; Apparue dans: IEEE Latin America Transactions Date publication: 10.-2017, volume: 15, issue:10, pages: 1834 - 1839 Editeur: IEEE Document complet vers site de l'éditeur
» Design of License Plate RFID Tag Antenna Using Characteristic Mode Pattern Synthesis
 Résumé:A novel design of the passive license plate radio frequency identification tag antenna in UHF band based on the characteristic mode theory (CMT) is proposed in this paper. The license plate is operated as a tag antenna since it is conductor (made of aluminum). A desired up-tilted pattern beam is achieved successfully by using a direct CMT-based radiation pattern synthesis procedure. The pattern can be expanded as a superposition of some specific characteristic modes pattern, which is identified according to characteristic mode analysis of the plate. Four coupling slots are exploited to excite the selected modes current distribution. The mode weighting coefficients can be tuned to form the desired pattern beam by changing the relative phase between the coupling slots. The feed structure is carefully designed without damaging the layout of characters and numbers on the license plate. The synthesized radiation pattern corresponds with the pattern simulated by HFSS. The measured radiation pattern proves that the proposed design is reliable and applicable. The measured read range is about 20 m, which can satisfy the actual requirements. Auteurs: Zhipeng Liang;Jun Ouyang;Feng Yang;Longjian Zhou; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 4964 - 4970 Editeur: IEEE Document complet vers site de l'éditeur
» Design of Miniaturized Triplexers via Sharing a Single Triple-Mode Cavity Resonator
 Résumé:A novel approach for design of a miniaturized cavity triplexer is proposed in this paper by using triple-mode resonator (TMR) as a common feeder of three frequency channels in a triplexer. Three frequency channels are generated by three fundamental modes of a single rectangular triple-mode cavity resonator. Without installing any connection-oriented junction network, i.e., T-junction or star junction, only coupling slots are adopted herein to achieve required coupling coefficients and external quality factors toward the specified Chebyshev responses in the three passbands simultaneously. High isolation among these three separated bands can be effectively achieved owing to the modal orthogonality via sharing a common TMR structure as a feeder. Two triplexers are then designed and fabricated using varied topologies. The hybrid resonator triplexer method is presented as the first approach by using a TMR as a feeder to feed three sets of single-mode cavity bandpass filters. As the second approach, the triple-mode triplexer (TMT) method is developed by cascading a few TMRs to form a multistage higher order TMT. Finally, two fabricated triplexer prototypes are tested for experimental verification of the proposed design methodology. Good agreement between measurement and simulation is achieved. Auteurs: Jing-Yu Lin;Sai-Wai Wong;Lei Zhu;Qing-Xin Chu; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3877 - 3884 Editeur: IEEE Document complet vers site de l'éditeur
» Design Procedure of Flux Reversal Permanent Magnet Machines
 Résumé:Flux reversal permanent magnet machines (FRPMMs) exhibit many advantages such as simple rotor configuration, high torque density, fast transient response, etc. However, the general analytical design procedure of FRPMMs has not been established. Thus, this paper mainly focuses on developing an analytical design methodology of three-phase FRPMMs. First, the sizing equations are derived based on a magneto motive force-permeance model. Then, the influences of several key parameters in the sizing equation, including slot–pole combination, airgap radius, electric loading, and equivalent magnetic loading on the torque density, are analyzed. Moreover, the feasible slot–pole combinations are summarized and the corresponding winding type of each combination is recommended in order to maximize the output torque. Additionaly, the detailed geometric design of stator and rotor is presented. Finally, the proposed analytical design procedure is verified by finite element analysis and experiments on a 12-stator-slot/17-rotor-slot FRPMM prototype. Auteurs: Yuting Gao;Dawei Li;Ronghai Qu;Jian Li; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4232 - 4241 Editeur: IEEE Document complet vers site de l'éditeur
» Design, Fabrication, and Characterization of a High Q Silica Nanobeam Cavity With Orthogonal Resonant Modes
 Résumé:We design and fabricate a high $Q$ silica nanobeam cavity that supports both transverse electric (TE) and transverse magnetic modes in the 1.55  $\mathrm{\mu }$m wavelength range. The $Q$ values obtained for both modes exceed $10^4$ and are the highest reported values for photonic crystal (PhC) nanocavities made of silica. We also investigate the optimum conditions for coupling with the cavity in a side-coupled configuration. We achieve a coupling efficiency of 87% with the TE mode while maintaining a loaded $Q$ of more than $10^4$. We also found that the presence of a coupled waveguide reduces the intrinsic $Q$ of the cavity, depending on the gap distance. This provides useful quantitative information for establishing an efficient scheme for coupling with low-index PhC nanocavities. Auteurs: Tomohiro Tetsumoto;Hajime Kumazaki;Kentaro Furusawa;Norihiko Sekine;Takasumi Tanabe; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 9 Editeur: IEEE Document complet vers site de l'éditeur
» Design, Fabrication, and Characterization of Scandium Aluminum Nitride-Based Piezoelectric Micromachined Ultrasonic Transducers
 Résumé:This paper presents the design, fabrication, and characterization of piezoelectric micromachined ultrasound transducers (PMUTs) based on scandium aluminum nitride (ScxAl1–xN) thin films (x = 15%). ScAlN thin film was prepared with a dual magnetron system and patterned by a reactive ion etching system utilizing chlorine-based chemistry with an etching rate of 160 nm/min. The film was characterized by X-ray diffraction, which indicated a crystalline structure expansion compared with pure AlN and a well-aligned ScAlN film. ScAlN PMUTs were fabricated by a two-mask process based on cavity SOI wafers. ScAlN PMUTs with 50- and 40- $\mu \text{m}$ diameter had a large dynamic displacement sensitivity measured in air of 25 nm/V at 17 MHz and 10 nm/V at 25 MHz, twice that of AlN PMUTs with the same dimensions. The peak displacement as a function of electrode coverage was characterized, with maximum displacement achieved with an electrode radius equal to 70% of the PMUT radius. Electrical impedance measurements indicated that the ScAlN PMUTs had 36% greater electromechanical coupling coefficient ( $\text{k}_{\mathrm {t}}^{2})$ compared with AlN PMUTs. The output pressure of a $7\times7$ ScAlN PMUT array was 0.7 kPa/V at ~1.7 mm away from the array, which is approximately three times greater that of an $8\times8$ AlN PMUT array with the same element geometry and fill factor measured at the same distance. Acoustic spreading loss and PMUT insertion loss from mechanical transmit to receive were characterized with a 15 $\times$ 15 ScAlN PMUT array via hydrophone and laser Doppler vibrometer. [17509-2017] Auteurs: Qi Wang;Yipeng Lu;Sergey Mishin;Yury Oshmyansky;David A. Horsley; Apparue dans: Journal of Microelectromechanical Systems Date publication: 10.-2017, volume: 26, issue:5, pages: 1132 - 1139 Editeur: IEEE Document complet vers site de l'éditeur
» Design, Modeling, Lab, and Field Tests of a Mechanical-Motion-Rectifier-Based Energy Harvester Using a Ball-Screw Mechanism
 Résumé:In this paper, a new-type of mechanical-motion-rectifier-based energy harvesting shock absorber using a ball-screw mechanism and two one-way clutches is proposed to replace conventional oil dampers in vehicle suspensions. The proposed energy-harvesting shock absorber can work as a controllable shock absorber as well as an energy harvester. The challenge to harvest energy from reciprocating suspension vibration is solved by integrating a mechanical motion rectifier in the proposed design, which can convert reciprocating vibration into unidirectional rotation of a generator. As a result, the proposed shock absorber achieves high energy-harvesting efficiency by enabling the generator to rotate at a relatively steady speed during irregular vibrations and improves system reliability by reducing impact forces in transmission gears. In addition, the backlash of the proposed shock absorber is significantly reduced due to the use of the ball-screw mechanism, which further increases transmission durability and efficiency. Lab and field tests are carried out to experimentally characterize the proposed energy-harvesting shock absorber. The field testing results show that, when the modified vehicle is driven on a paved road at 40 mph, the proposed energy-harvesting shock absorber is able to reduce the root-mean-square value of chassis acceleration by 11.12% over the oil shock absorber and simultaneously harvest an average power of 13.3 W for a representative period of 8 s. Auteurs: Yilun Liu;Lin Xu;Lei Zuo; Apparue dans: IEEE/ASME Transactions on Mechatronics Date publication: 10.-2017, volume: 22, issue:5, pages: 1933 - 1943 Editeur: IEEE Document complet vers site de l'éditeur
» Designing, Manufacturing and Testing of a Piezoelectric Polymer Film In-Sole Sensor for Plantar Pressure Distribution Measurements
 Résumé:We have designed, manufactured, and tested a prototype of an in-sole plantar pressure sensor. The sensor is made of a piezoelectric polymer film (polyvinylidenefluoride, PVDF) with evaporated copper electrodes. The size and the location of measuring sites are carefully considered to produce a light-weighted, practical, and inexpensive matrix sensor for measurement of plantar pressure distribution. The sensor consists of eight measurement locations: hallux, first metatarsal head (under both sesamoid bones), metatarsal heads 2–5 and heel. The developed in-sole sensor was evaluated through piezoelectric sensitivity measurements and test measurements with subjects (used as a platform sensor). Average peak-to-peak pressures from 58 to 486 kPa were obtained in plantar pressure measurements. The in-sole sensor can be used to prevent pressure ulcers. Also other application areas for the sensor are available, e.g., rehabilitation and sports. The developed sensor enables unobtrusive and long-term plantar pressure measurements. In future, an option for manufacturing the PVDF in-soles may be printing of desired electrode pattern on PVDF material, that would allow fast production, and if needed, the production of even individual in-soles. Auteurs: Satu Rajala;Raisa Mattila;Ilkka Kaartinen;Jukka Lekkala; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6798 - 6805 Editeur: IEEE Document complet vers site de l'éditeur
» Desirably Adjusting Gain Margin, Phase Margin, and Corresponding Crossover Frequencies Based on Frequency Data
 Résumé:This paper presents an analytical method to tune a fixed-structure fractional-order compensator for satisfying desired phase and gain margins with adjustable crossover frequencies. The proposed method is based on the measured frequency data of the plant. Since no analytical model for the plant is needed in the compensator tuning procedure, the resulted compensator does not depend on the order and complexity of the plant. Also, sufficient conditions for the existence of a compensator with no zero and pole in the right half-plane for satisfying the aforementioned objectives are analytically derived. Furthermore, different hardware-in-the-loop experimental results are presented to show the efficiency of the proposed tuning method. Auteurs: Negin Sayyaf;Mohammad Saleh Tavazoei; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2311 - 2321 Editeur: IEEE Document complet vers site de l'éditeur
» Detailed Measurement Study of Spatial Similarity in Spectrum Use in Dense Urban Environments
 Résumé:We present a detailed analysis of spectrum use and radio environment dynamics based on extensive measurement campaigns in the two European metropolitan areas of Paris and London. Our focus is twofold. First, for the Paris case we focus on frequency bands assigned to cellular systems. In particular, we present extensive cross-correlational analyses describing the complex interdependencies in spectrum use between the various bands, together with their spatial correlation structures. Our results show that there are strong correlations in many instances, but these are not present in all regions and for all technologies. Second, we focus on characterizing the variability in spectrum use using novel methodology going beyond the classical spatial correlation analysis. For this, we carry out detailed measurements over different areas of London, using both moving measurement platforms as well as a stationary reference. The utilized measurement approach allows us to study the scales of variation in an area, which are important for secondary access systems and cognitive network types of deployments that have to understand and exploit those. Such deployments depend on various boundary conditions on the radio dynamics. Our major methodological contribution is that we do not only use a local average with the simplest spatial dependency measure (linear correlation), but we retain all the data and quantify spatial similarly using distribution-wide metrics. This approach also allows us to question how much information can indeed be shared from relay nodes or single nodes measurements that try to capture dynamics of larger operating regions. Auteurs: Alexandros Palaios;Janne Riihijärvi;Oliver Holland;Petri Mähönen; Apparue dans: IEEE Transactions on Vehicular Technology Date publication: 10.-2017, volume: 66, issue:10, pages: 8951 - 8963 Editeur: IEEE Document complet vers site de l'éditeur
» Detecting Clinically Meaningful Shape Clusters in Medical Image Data: Metrics Analysis for Hierarchical Clustering Applied to Healthy and Pathological Aortic Arches
 Résumé:Objective: Today's growing medical image databases call for novel processing tools to structure the bulk of data and extract clinically relevant information. Unsupervised hierarchical clustering may reveal clusters within anatomical shape data of patient populations as required for modern precision medicine strategies. Few studies have applied hierarchical clustering techniques to three-dimensional patient shape data and results depend heavily on the chosen clustering distance metrics and linkage functions. In this study, we sought to assess clustering classification performance of various distance/linkage combinations and of different types of input data to obtain clinically meaningful shape clusters. Methods: We present a processing pipeline combining automatic segmentation, statistical shape modeling, and agglomerative hierarchical clustering to automatically subdivide a set of 60 aortic arch anatomical models into healthy controls, two groups affected by congenital heart disease, and their respective subgroups as defined by clinical diagnosis. Results were compared with traditional morphometrics and principal component analysis of shape features. Results: Our pipeline achieved automatic division of input shape data according to primary clinical diagnosis with high F-score (0.902 ± 0.042) and Matthews correlation coefficient (0.851 ± 0.064) using the correlation/weighted distance/linkage combination. Meaningful subgroups within the three patient groups were obtained and benchmark scores for automatic segmentation and classification performance are reported. Conclusion: Clustering results vary depending on the distance/linkage combination used to divide the data. Yet, clinically relevant shape clusters and subgroups could be found with high specificity and low miscl- ssification rates. Significance: Detecting disease-specific clusters within medical image data could improve image-based risk assessment, treatment planning, and medical device development in complex disease. Auteurs: Jan L. Bruse;Maria A. Zuluaga;Abbas Khushnood;Kristin McLeod;Hopewell N. Ntsinjana;Tain-Yen Hsia;Maxime Sermesant;Xavier Pennec;Andrew M. Taylor;Silvia Schievano; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 10.-2017, volume: 64, issue:10, pages: 2373 - 2383 Editeur: IEEE Document complet vers site de l'éditeur
» Detecting Malicious Activity With DNS Backscatter Over Time
 Résumé:Network-wide activity is when one computer (the originator) touches many others (the targets). Motives for activity may be benign (mailing lists, content-delivery networks, and research scanning), malicious (spammers and scanners for security vulnerabilities), or perhaps indeterminate (ad trackers). Knowledge of malicious activity may help anticipate attacks, and understanding benign activity may set a baseline or characterize growth. This paper identifies domain name system (DNS) backscatter as a new source of information about network-wide activity. Backscatter is the reverse DNS queries caused when targets or middleboxes automatically look up the domain name of the originator. Queries are visible to the authoritative DNS servers that handle reverse DNS. While the fraction of backscatter they see depends on the server’s location in the DNS hierarchy, we show that activity that touches many targets appear even in sampled observations. We use information about the queriers to classify originator activity using machine-learning. Our algorithm has reasonable accuracy and precision (70–80%) as shown by data from three different organizations operating DNS servers at the root or country level. Using this technique, we examine nine months of activity from one authority to identify trends in scanning, identifying bursts corresponding to Heartbleed, and broad and continuous scanning of secure shell. Auteurs: Kensuke Fukuda;John Heidemann;Abdul Qadeer; Apparue dans: IEEE/ACM Transactions on Networking Date publication: 10.-2017, volume: 25, issue:5, pages: 3203 - 3218 Editeur: IEEE Document complet vers site de l'éditeur
» Detecting Sudden and Gradual Drifts in Business Processes from Execution Traces
» Detection of Cars in High-Resolution Aerial Images of Complex Urban Environments
 Résumé:Detection of small targets, more specifically cars, in aerial images of urban scenes, has various applications in several domains, such as surveillance, military, remote sensing, and others. This is a tremendously challenging problem, mainly because of the significant interclass similarity among objects in urban environments, e.g., cars and certain types of nontarget objects, such as buildings’ roofs and windows. These nontarget objects often possess very similar visual appearance to that of cars making it hard to separate the car and the noncar classes. Accordingly, most past works experienced low precision rates at high recall rates. In this paper, a novel framework is introduced that achieves a higher precision rate at a given recall than the state of the art. The proposed framework adopts a sliding-window approach and it consists of four stages, namely, window evaluation, extraction and encoding of features, classification, and postprocessing. This paper introduces a new way to derive descriptors that encode the local distributions of gradients, colors, and texture. Image descriptors characterize the aforementioned cues using adaptive cell distributions, wherein the distribution of cells within a detection window is a function of its dominant orientation, and hence, neither the rotation of the patch under examination nor the computation of descriptors at different orientations is required. The performance of the proposed framework has been evaluated on the challenging Vaihingen and Overhead Imagery Research data sets. Results demonstrate the superiority of the proposed framework to the state of the art. Auteurs: Mohamed ElMikaty;Tania Stathaki; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 10.-2017, volume: 55, issue:10, pages: 5913 - 5924 Editeur: IEEE Document complet vers site de l'éditeur
» Detection of False-Data Injection Attacks in Cyber-Physical DC Microgrids
 Résumé:Power electronics-intensive dc microgrids use increasingly complex software-based controllers and communication networks. They are evolving into cyber-physical systems (CPS) with sophisticated interactions between physical and computational processes, making them vulnerable to cyber attacks. This paper presents a framework to detect possible false-data injection attacks (FDIAs) in cyber-physical dc microgrids. The detection problem is formalized as identifying a change in sets of inferred candidate invariants. Invariants are microgrids properties that do not change over time. Both the physical plant and the software controller of CPS can be described as Simulink/Stateflow (SLSF) diagrams. The dynamic analysis infers the candidate invariants over the input/output variables of SLSF components. The reachability analysis generates the sets of reachable states (reach sets) for the CPS modeled as hybrid automata. The candidate invariants that contain the reach sets are called the actual invariants. The candidate invariants are then compared with the actual invariants, and any mismatch indicates the presence of FDIA. To evaluate the proposed methodology, the hybrid automaton of a dc microgrid, with a distributed cooperative control scheme, is presented. The reachability analysis is performed to obtain the reach sets and, hence, the actual invariants. Moreover, a prototype tool, HYbrid iNvariant GEneratoR, is extended to instrument SLSF models, obtain candidate invariants, and identify FDIA. Auteurs: Omar Ali Beg;Taylor T. Johnson;Ali Davoudi; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2693 - 2703 Editeur: IEEE Document complet vers site de l'éditeur
» Detection of Underwater Targets Using a Subspace-Based Method With Learning
 Résumé:This paper introduces a new subspace-based detection method for multichannel (high frequency and broadband) synthetic aperture sonar (SAS) imagery. An image-dependent dictionary learning method is applied to form the appropriate dictionary matrices for representing target and nontarget image snippets. The hypothesis testing is done by forming a test statistic that relies on the residual error power ratio in representing an unknown image snippet using the target and nontarget dictionary matrices. To avoid the computational bottleneck in most dictionary learning methods, a new recursive method is introduced which does not require any matrix inversion or singular value decomposition (SVD). The proposed detection method was then implemented and benchmarked against a matched subspace detection method for detecting mine-like objects. Results are then presented on two sonar imagery data sets collected in two geographically disparate locations. Auteurs: Mahmood R. Azimi-Sadjadi;Nick Klausner;Justin Kopacz; Apparue dans: IEEE Journal of Oceanic Engineering Date publication: 10.-2017, volume: 42, issue:4, pages: 869 - 879 Editeur: IEEE Document complet vers site de l'éditeur
» Determination of Original Nondegraded and Fully Degraded Magnetic Characteristics of Material Subjected to Laser Cutting
 Résumé:The degrading effect of laser cutting on steel sheet material, and thus on the material's magnetic characteristics, is much less understood than that of mechanical cutting. Furthermore, the degrading influence on the magnetic properties is still difficult to determine. This paper focuses on the modeling of the degrading influence of laser cutting on the magnetic properties of electrical steel sheets. As the degradation depth and the degradation profile are still difficult to define, a method is needed, which takes the effect of laser cutting into account, but without the need of knowing the degradation profile exactly. This paper shows that a method that does not require any information on the physical phenomena that are introduced by the cutting process and that has already been verified for mechanically cut samples can also be applied to laser-cut samples, although the deterioration mechanisms and the resulting degradation profile and depths differ. Magnetic characteristics are identified for two different material zones and subsequently inserted into a finite-element model, which accounts for arbitrary geometries. The simulation results for the influence of laser cutting on the magnetic characteristics of the stator lamination stacks are verified by measurements, including three different materials and frequencies. Auteurs: Madeleine Bali;Herbert De Gersem;Annette Muetze; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4242 - 4251 Editeur: IEEE Document complet vers site de l'éditeur
» Determine Q–V Characteristics of Grid-Connected Wind Farms for Voltage Control Using a Data-Driven Analytics Approach
 Résumé:Due to the varying and intermittent nature of wind resource, grid-connected wind farms pose significant technical challenges to power grid on power quality and voltage stability. Wind farm Q–V characteristic curve at the point of interconnection (POI) can offer valuable information for voltage control actions and provide essential indication about voltage stability. Data-driven analytics is a promising approach to determine characteristics of a large complex system, a physical model of which is difficult to obtain. In this paper, data-driven analytics is used to determine Q–V curve of grid-connected wind farms based on measurement data recorded at the POI. Different curve-fitting models, such as polynomial, Gaussian, and rational, are evaluated, and the best fit is determined based on different graphical and numerical evaluation metrics. A case study is conducted using field measurement data at two grid-connected wind farms currently in operation in Newfoundland and Labrador, Canada. It is found that the Gaussian (degree 2) model describes the Q–V relationship most accurately for the two wind farms. The obtained functions and processed data can be used in the voltage controller design. The plotted QV curve can also be used to determine the reactive margin at the POI for voltage stability evaluation. As a generic method, the proposed approach can be employed to determine Q–V characteristic curve of any grid-connected large wind farms. Auteurs: Chowdhury Andalib-Bin-Karim;Xiaodong Liang;Nahidul Khan;Huaguang Zhang; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4162 - 4175 Editeur: IEEE Document complet vers site de l'éditeur
» Deuterated SiN/SiON Waveguides on Si Platform and Their Application to C-Band WDM Filters
 Résumé:We describe low-loss SiN/SiON waveguides for wavelength-division-multiplexing filters on a Si platform. The key technology is a low-temperature deposition of refractive-index-controllable SiN/SiON films by using a hydrogen-free gas source (SiD4), which avoids the strong optical absorption due to N-H bond. Using this technology, we demonstrate a low-loss ring resonator with a SiN waveguide, whose loss is 0.47 dB/cm at 1550 nm. It shows excess loss of 2.7 dB, a 3-dB bandwidth of 0.13 nm, and an extinction ratio of 27 dB in the entire C band. In addition, we also demonstrate a polarization-insensitive arrayed-waveguide grating with a SiON waveguide, whose loss is 0.29 dB/cm at 1550 nm. It shows insertion loss of 5.3 dB, crosstalk of less than −27 dB, and polarization insensitivity in the entire C band. Auteurs: Tatsurou Hiraki;Takuma Aihara;Hidetaka Nishi;Tai Tsuchizawa; 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
» Developing Millimeter-Wave Planar Antenna With a Cosecant Squared Pattern
 Résumé:This communication reports a novel planar array antenna having a cosecant squared pattern for millimeter-wave communication systems. The substrate integrated waveguide, which has high quality factor, low transmission loss, and no parasitic radiation, has been adopted to develop the proposed antenna. To improve the design efficiency, the aggressive space mapping (ASM) algorithm is used for synthesizing the desired excitations with low computation cost and high accuracy. A radiation model that considers mutual couplings among element antennas is developed based on the active element pattern for the coarse model of the ASM. And the genetic algorithm is adopted for the parameter mapping and extraction of the ASM process. As a demonstration, a prototype has been designed with a center frequency of 42.6 GHz, and experiments are carried out to verify the design. The measured results show that the measured antenna has a cosecant squared region up to 40°, a gain of 17.7 dBi at 42.6 GHz, and the maximum sidelobe is lower than −16.5 dB. The proposed antenna can be used for the base station of the long-range Qlink-Pan communication system. Auteurs: Zhang-Cheng Hao;Muxin He; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5565 - 5570 Editeur: IEEE Document complet vers site de l'éditeur
» Development and Characterization of an H-Shaped Microresonator Exhibiting 2:1 Internal Resonance
 Résumé:This paper reports on the design and characterization of an $H$ -shaped microresonator exhibiting nonlinear modal interactions due to 2:1 internal resonance. This has been made possible through careful design of the structure with attention to the limits of microfabricated devices. The intended nonlinear dynamics rely on the continuous transfer of energy between the anti-phase motions of two $H$ -like proof masses of the device to a mode along the orthogonal direction. Finite element and reduced order models of the structure were developed and used to design the devices with two desired flexural modes in a ~2:1 frequency ratio. The microresonator was fabricated in a commercial foundry process. Extensive experiments and transient simulations were conducted to verify the desired nonlinear responses and the models. It was demonstrated that the low-frequency mode of the device was excited through auto-parametric excitation of the higher frequency mode when the excitation level exceeded a specific threshold as expected. The device design methodologies can be employed to fabricate various sensors, including nonlinear Coriolis vibratory gyroscopes incorporating 2:1 internal resonance. [2017-0035] Auteurs: Atabak Sarrafan;Behraad Bahreyni;Farid Golnaraghi; Apparue dans: Journal of Microelectromechanical Systems Date publication: 10.-2017, volume: 26, issue:5, pages: 993 - 1001 Editeur: IEEE Document complet vers site de l'éditeur
» Development and Test of a Diamond-Based Fast Neutron Detector for 200 °C Operation
 Résumé:Recent improvements in the production of artificial single-crystal diamonds have made it possible to produce commercial radiation detectors. However, the availability of diamond detectors for high-temperature and high-shock applications is limited. We have developed a compact solid-state diamond detector for high-temperature applications which require compact size, stable performance, and extreme ruggedness. It is used as a fast neutron detector for monitoring the output of a pulsed neutron generator in oil well-logging tools. The sensor consists of a high-purity monocrystalline diamond wafer with metallized electrodes on both faces. One of the metallized surfaces is mounted on a metallic plate resting on a ceramic substrate. The metallized diamond assembly is mounted in a TO-257 metal housing, which has pins connected to the two electrodes on the two faces of the diamond. The detector package, consisting of the diamond sensor and the electronics assembly, has been qualified for operation in the harsh downhole environment of oil fields. This includes high temperature and repeated shocks and vibration. Units have been tested for up to 150 h at 200 °C with no degradation in signal or count rate accuracy. The count rate accuracy with a simple detection threshold regulation scheme can reach ±1% over the range from 25 °C to 200 °C. However, this detector has applications beyond well logging, wherever there is a need for a compact, reliable detector for fast neutrons in an environment where ruggedness, exposure to high temperature, compactness, and radiation hardness are essential. Auteurs: Olivier Philip;Frederic Gicquel;Vincent Ernst;Zilu Zhou; Apparue dans: IEEE Transactions on Nuclear Science Date publication: 10.-2017, volume: 64, issue:10, pages: 2683 - 2689 Editeur: IEEE Document complet vers site de l'éditeur
» Development of a 1 kW direct methanol fuel cell system [News from Japan]
 Résumé:Global warming is a matter of primary concern in the world, and therefore suppression of CO2 emission is an urgent task. It follows that mass consumption of petroleum, coal, and natural gas must be reduced, and therefore development of renewable energy sources such as wind power, solar power, and fuel cells, with less CO2 emission, is necessary. Auteurs: Y. Ohki; Apparue dans: IEEE Electrical Insulation Magazine Date publication: 10.-2017, volume: 33, issue:5, pages: 52 - 55 Editeur: IEEE Document complet vers site de l'éditeur
» Development of a 1.5 kV, 1.2 kA Pulsed-Power Supply for Light Sintering
 Résumé:This paper presents the design and experimental results of the 36-kW pulsed-power supply for the xenon flash lamp. The continuous conduction mode series-parallel resonant converter is modified. This means that not only the few hundred kilohertz of high switching frequency is introduced to replace the resonant inductor with the leakage inductor of transformer but also the high output current is accomplished by using three-phase delta-connected transformers. In addition, the snubber capacitor of the inverter switches and the power factor correction module is both omitted in the compact structure. Although these main components have changed, the efficiency and power factor of the rated dummy load reach 96% and 0.96%, respectively. Within 36-kW average power, the proposed pulsed-power supply can generate as versatile combination of output pulse. For example, it can generate 20-ms pulse with 1-Hz repetition rate or generate 1-ms pulse with 20-Hz repetition rate. The used insulated gate bipolar transistor is protected from the turn-OFF peak voltage by the snubber circuit, and the effect of the snubber circuit is shown at the actual load condition. Auteurs: Chan-Gi Cho;Seung-Ho Song;Su-Mi Park;Hyeon-Il Park;Jung-Soo Bae;Sung-Roc Jang;Hong-Je Ryoo; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2683 - 2690 Editeur: IEEE Document complet vers site de l'éditeur
» Development of a Novel Robotic Dolphin and Its Application to Water Quality Monitoring
 Résumé:This paper presents the mechatronic design and hydrodynamic analysis of a novel bioinspired robotic dolphin used for mobile water quality monitoring. A complementary configuration for mimicry of dolphin-like propulsion is first presented, involving a waist–fluke propulsive unit for dorsoventral oscillations and a pair of flippers with separate degree of freedom for three-dimensional (3-D) maneuvers. A host of onboard sensors is equipped to strengthen the capability of environment perception and mission execution on a near real-time basis. Considering the dynamic requirement for motion transition in water quality monitoring, a central pattern generator based controller is then built to govern the multimodal locomotion of the robotic dolphin. Moreover, a 3-D dynamic model based on the Lagrange method is employed to predict the propulsive performance, followed by simulations of continuous diving and surfacing motions. Finally, both laboratory and field experiments are conducted to demonstrate the effectiveness of the presented mechatronic design and control methods. The results further show that the robotic dolphin with 3-D maneuverability offers a feasible solution to aquatic mobile sensing. Auteurs: Zhengxing Wu;Jincun Liu;Junzhi Yu;Hao Fang; Apparue dans: IEEE/ASME Transactions on Mechatronics Date publication: 10.-2017, volume: 22, issue:5, pages: 2130 - 2140 Editeur: IEEE Document complet vers site de l'éditeur
» Development of a Stator-Magnetless Linear Synchronous Motor for Sensorless Control
 Résumé:Sensorless control techniques that do not use a linear scale are desired for applications that require a long-stroke linear synchronous motor (LSM). This paper discusses the development of a stator-magnetless LSM (i.e., no magnet is mounted on the stator of the LSM) for sensorless control that includes a high-speed position estimation algorithm based on the magnetic saturation phenomenon. This paper presents a new structure of a flux-switching LSM that achieves a high saliency ratio using a cutout that results in magnetic saturation in the armature core. The effect of the sub-tooth on reducing the cogging thrust is also discussed. Furthermore, the analytical and experimental characteristics of inductance, thrust, cogging thrust, and sensorless drive control are discussed based on a prototype. Auteurs: Shogo Makino;Masanobu Kakihara;Yoshiyasu Takase;Mamoru Takaki;Toru Shikayama;Motomichi Ohto;Tsuyoshi Higuchi;Takashi Abe; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4559 - 4568 Editeur: IEEE Document complet vers site de l'éditeur
» Development of an Enhanced Electromagnetic Actuation System With Enlarged Workspace
 Résumé:Electromagnetic actuation is an emerging wireless control approach for manipulating magnetic microparticles for diverse minimally invasive therapy and diagnosis. This paper presents an enhanced electromagnetic manipulation system with an enlarged workspace, which is achieved by both the parametric design and the quantitative modeling of generated magnetic field of the system. The parametric design aims to characterize the influence of electromagnet parameters, such as position, radius, and height of cores on the generated electromagnetic field, so that the electromagnet specifications of the developed system can achieve a large workspace, while possessing the desired magnetic field flux density (MFFD) and gradient. With this design, the workspace of the developed prototype can reach a spherical volume with a diameter of 110 mm, the MFFD can reach 100 mT, and the gradient of MFFD can reach 2.5 T/m. The spatial distribution of electromagnetic field is quantitatively modeled using the finite-element method. Based on this model, a unit electromagnetic field distribution database for a 3-D grid of points is established. Such database enables the effective manipulation of microparticles in a considerably large workspace rather than only small central area. Experiments of manipulating paramagnetic microparticles in both 2-D and 3-D scenarios are performed to demonstrate the effectiveness of the designed system. Auteurs: Fuzhou Niu;Junyang Li;Weicheng Ma;Jie Yang;Dong Sun; Apparue dans: IEEE/ASME Transactions on Mechatronics Date publication: 10.-2017, volume: 22, issue:5, pages: 2265 - 2276 Editeur: IEEE Document complet vers site de l'éditeur
» Development of LiDAR-Based UAV System for Environment Reconstruction
 Résumé:In disaster management, reconstructing the environment and quickly collecting the geospatial data of the impacted areas in a short time are crucial. In this letter, a light detection and ranging (LiDAR)-based unmanned aerial vehicle (UAV) is proposed to complete the reconstruction task. The UAV integrate an inertial navigation system (INS), a global navigation satellite system (GNSS) receiver, and a low-cost LiDAR. An unmanned helicopter is introduced and the multisensor payload architecture for direct georeferencing is designed to improve the capabilities of the vehicle. In addition, a new strategy of iterative closest point algorithm is proposed to solve the registration problems in the sparse and inhomogeneous derived point cloud. The proposed registration algorithm addresses the local minima problem by the use of direct-georeferenced points and the novel hierarchical structure as well as taking the feedback bias into INS/GNSS. The generated point cloud is compared with a more accurate one derived from a high-grade terrestrial LiDAR which uses real flight data. Results indicate that the proposed UAV system achieves meter-level accuracy and reconstructs the environment with dense point cloud. Auteurs: Kai-Wei Chiang;Guang-Je Tsai;Yu-Hua Li;Naser El-Sheimy; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1790 - 1794 Editeur: IEEE Document complet vers site de l'éditeur

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2017:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2016:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2015:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2014:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2013:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2012:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2011:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2010:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2009:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre