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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 05-2017 trié par par titre, page: 3
» Combined Speed and Direct Thrust Force Control of Linear Permanent-Magnet Synchronous Motors With Sensorless Speed Estimation Using a Sliding-Mode Control With Integral Action
Résumé:
A sliding-mode-based control scheme with integral action for combined speed and direct thrust force control of a linear permanent-magnet synchronous motor is proposed. A nonlinear state-space model for the combined dynamics of speed and thrust force as system states is utilized for the synthesis of the sliding-mode control law. Direct integral action is also included in the control law to eliminate the steady-state error in the speed tracking. The sensorless speed estimation is performed by using an adaptive flux observer with a modified dual boundary layer sliding-mode component. Lyapunov stability analysis to prove the global asymptotic stabilities of both the controller and observer is provided. The effectiveness of the proposed method is validated experimentally and demonstrates excellent transient and steady-state speed control performance.
Auteurs: Muhammad Ali Masood Cheema;John Edward Fletcher;Mohammad Farshadnia;Dan Xiao;Muhammad Faz Rahman;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3489 - 3501
Editeur: IEEE
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» Comments on “An Analytical Design Method for a Novel Dual-Band Unequal Coupler With Four Arbitrary Terminated Resistances”
Résumé:
IN the above paper [1], the authors proposed a dual-band unequal power division branch line coupler(BLC) with four arbitrary terminated resistance using dual-band impedance matching network (IMN) and BLC with complex port impedance. However the authors have not considered the transmission phase of the IMNs [2] and the BLC, which leads to non-quadrature phase difference (6 S21􀀀6 S31 6= 90) at the output ports when the termination resistances are unequal.
Auteurs: Rakesh Sinha;Arijit De;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4068 - 4069
Editeur: IEEE
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» Comments on “Simultaneous Reduction of Petri Nets and Linear Constraints for Efficient Supervisor Synthesis”
Résumé:
The above paper [1] proposes a method to reduce simultaneously a Petri net model and the linear constraints. The reduced result preserves the control specification and the liveness. This note shows via some simple counterexamples that some results claimed in the above paper are incorrect, and then presents the corresponding corrections for two of the results.
Auteurs: Ning Ran;Shouguang Wang;Hongye Su;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2603 - 2606
Editeur: IEEE
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» Communications and Signals Design for Wireless Power Transmission
Résumé:
Radiative wireless power transfer (WPT) is a promising technology to provide cost-effective and real-time power supplies to wireless devices. Although radiative WPT shares many similar characteristics with the extensively studied wireless information transfer or communication, they also differ significantly in terms of design objectives, transmitter/receiver architectures and hardware constraints, and so on. In this paper, we first give an overview on the various WPT technologies, the historical development of the radiative WPT technology and the main challenges in designing contemporary radiative WPT systems. Then, we focus on the state-of-the-art communication and signal processing techniques that can be applied to tackle these challenges. Topics discussed include energy harvester modeling, energy beamforming for WPT, channel acquisition, power region characterization in multi-user WPT, waveform design with linear and non-linear energy receiver model, safety and health issues of WPT, massive multiple-input multiple-output and millimeter wave enabled WPT, wireless charging control, and wireless power and communication systems co-design. We also point out directions that are promising for future research.
Auteurs: Yong Zeng;Bruno Clerckx;Rui Zhang;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 2264 - 2290
Editeur: IEEE
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» Compact 35–70 GHz SPDT Switch With High Isolation for High Power Application
Résumé:
This letter proposes a broadband high isolation and high power compact single pole double throw (SPDT) switch. In contrast to the traditional structure of grounded source pad, the source pad of the shunt-stacked FET is absorbed into the transmission line, and the drain of the shunt-stacked FET is grounded to a via-hole. This structure helps to extend the operation bandwidth and reduce the chip size. The proposed SPDT switch is composed of six shunt-stacked FET units on each branch with this novel structure. Stacked FETs technique increases the voltage handling by placing two FETs in series. It has been fabricated using a commercial $0.1~boldsymbol {mu }text{m}$ GaAs pseudomorphic high-electron-mobility transistor (PHEMT) process. The chip size is $1.2times 0.8$ mm2. The switch operates at the frequency range of 35–70 GHz with less than 3 dB insertion loss and more than 40-dB isolation. The switch demonstrates a 1 dB insertion loss compression with a 20.2 dBm input power at 31 GHz. The isolation is larger than 30 dB from 10 to 95 GHz. To the best of the authors’ knowledge, this broadband isolation performance is among the best of the reported SPDT switches.
Auteurs: Li Zhao;Wen-Feng Liang;Jian-Yi Zhou;Xin Jiang;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 485 - 487
Editeur: IEEE
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» Compact Folded Dipole With Embedded Matching Loop for Universal Tag Applications
Résumé:
A coin-shaped folded dipole is proposed for designing a UHF tag that can be placed in free space and on metal. The proposed tag antenna is compact ( $0.095lambda )$ and low in profile (1.6 mm). It is composed of a matching loop, which is encircled by two patch-shaped radiating arms, forming an embedded structure that has high compactness. Slots are etched in the radiators for fine-tuning the resonant frequency. An equivalent circuit has also been obtained for analyzing the impedance characteristics of the tag antenna across the frequency range, and it is found that the radiating element itself is capacitive and inclusion of the matching loop is essential for making the tag antenna inductive for achieving good matching with the chip. Simulation and experiment have been conducted to study the charateristics of the proposed tag antenna. When tested in free space with an Effective Isotropic Radiated Power (EIRP) input power of 3.28 W, the tag antenna is able to reach a maximum read range of 5.2 m, but it reduces to 1.8 m when placed on metal. Also, the resonant frequency of the proposed tag antenna is found to be stable and not affected much by its backing object.
Auteurs: Fwee-Leong Bong;Eng-Hock Lim;Fook-Loong Lo;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2173 - 2181
Editeur: IEEE
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» Compact Multimode Monopole Antenna for Metal-Rimmed Mobile Phones
Résumé:
A compact multimode monopole antenna for hepta-band metal-rimmed smartphones is proposed. The metal bezel is kept unbroken and no lumped element is needed. To cover the low band, the bezel mode is excited by a capacitive coupling vertical plate, and a bandwidth enhancement technique is introduced for this mode. For the high band, printed multiple branches on both sides of substrate are well designed to obtain multiple modes to cover a wide band. With the proposed structure, the frequency bands can be widened by tuning and optimization. The new-type monopole occupies an area of $60 times 5 times 5$ mm $^{3}$ on a $120 times 60$ mm $^{2}$ system board, which has a narrow ground clearance and a low profile. A prototype is fabricated and measured to validate the proposed design. Measured results show that the proposed antenna has two impedance bands with $S_{11}$ less than −6 dB, i.e., 23% for the low band (0.76–0.96 GHz) and 57% for the high band (1.51–2.72 GHz). The proposed monopole antenna is capable of covering the GSM/DCS/PCS/UMTS and LTE2300/2500 bands for modern metal-rimmed mobile phone applications.
Auteurs: Yaohui Yang;Zhiqin Zhao;Wei Yang;Zaiping Nie;Qing-Huo Liu;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2297 - 2304
Editeur: IEEE
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» Compact Neuromorphic System With Four-Terminal Si-Based Synaptic Devices for Spiking Neural Networks
Résumé:
In this paper, we propose a compact neuromorphic system that can work with four-terminal Si-based synaptic devices for spiking neural networks. The system consists of Si-based floating-body synaptic transistors and integrate-and-fire neuron circuit. The synaptic device can change its weight using floating-body effect and charge injection into the floating gate. The neuron circuit integrates signals from the synaptic devices through current mirrors and generates an action-potential when the integrated signal value exceeds a threshold value. The generated action potential that is transmitted to postsynaptic neurons is simultaneously returned to the back gate of the synaptic device for the change of weight based on spike-timing-dependent-plasticity. As the four-terminal synaptic device can transmit preneuron signals and change its weight at the same time, we can constitute the compact neuromorphic system without additional switches or logic operation and emulate the operation of neuron with a minimum number of devices and power dissipation (~3 pJ).
Auteurs: Jungjin Park;Min-Woo Kwon;Hyungjin Kim;Sungmin Hwang;Jeong-Jun Lee;Byung-Gook Park;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2438 - 2444
Editeur: IEEE
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» Compact UHF Three-Element Sequential Rotation Array Antenna for Satcom Applications
Résumé:
This paper proposes a miniaturized UHF antenna with three sequentially rotated elements operating at 433 MHz for Satcom applications. Like most of its former counterparts, the antenna consists of a main body with three radiation elements driven by a feeding network. To evaluate the matching characteristics of the main body, a united reflection coefficient for the three elements, taking into consideration the coupling between them, is derived. The main body is formed by three sequentially rotationally arranged bent planar inverted-F antenna elements, which helps dramatically reduce the size of the antenna. To drive the main body, a new compact feeding network based on spiral-shaped Wilkinson power divider is also developed, achieving three-way power splitting and 120° phase shifting. It has the merits of compact planar structure, equal power splitting, and high isolation between output ports. In this way, a sequential rotation array antenna with compact size (Ø $0.216lambda _{0}$ ), low cost, easy fabrication, and good performance is realized. A prototype is fabricated and measured, and the results prove the good performance of the proposed design.
Auteurs: Shaowei Liao;Quan Xue;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2328 - 2338
Editeur: IEEE
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» Comparative Analysis of the Doubly Fed Induction Generator (DFIG) Under Balanced Voltage Sag Using a Deadbeat Controller
Résumé:
This paper shows a Deadbeat controller for a wind generator during a balanced voltage sag condition. The control is made with a Stator Field Oriented Control technique using the DSOGI-QSG applied on the estimation of positive sequence of stator voltage vector and the stator current vector. The control strategy used is fully explained, and then it is tested using Matlab/Simulink, considering two scenarios: for the first one, the generator must be forced to generate reactive power and maintain the active power in zero, during voltage sag condition according with the new network requirements. For the second test, the generator must maintain rotor currents within safe levels to prevent damages for the windings during voltage sag. Simulation results and conclusions about controller perfomance during the voltage sag condition are presented.
Auteurs: Carlos Mario Rocha Osorio;Juan Sebastian Solis Chaves;Andre Luiz de Lacerda Ferreira Murari;Alfeu Joaozinho Sguarezi Filho;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 869 - 876
Editeur: IEEE
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» Comparing Performances of Crop Height Inversion Schemes From Multifrequency Pol-InSAR Data
Résumé:
Polarimetric synthetic aperture radar (SAR) interferometry has shown great potential to estimate the height of crops and forests by inverting simple scattering models of the canopy and the underlying soil. The random-volume-over-ground (RVoG) model assumes that the scatterers within the canopy (e.g., stalks and leaves) are not aligned along a preferred direction. If these scatterers are characterized by a correlation of orientations, then the scene is better described by the oriented-volume-over-ground (OVoG) model. This paper investigates the plausibility of the “random volume” and “oriented volume” assumptions, as well as the robustness of single- and dual-baseline inversion schemes in relation to agricultural crop height estimation. To this end, we implemented different single- and dual-baseline techniques for the inversion of the RVoG and OVoG models, and we evaluated their height retrieval performances with the help of simulated observations and experimental F-SAR measurements in L-, C-, and X-Bands. The inversion results revealed a positive relationship between the bias of the estimated height and the differential extinction when the RVoG inversion scheme is applied. By contrast, no such dependence was observed for the OVoG inversion, whose height estimates are on average consistent with the actual values (i.e., median bias below 10% in magnitude). Despite the observed superiority of dual-baseline approaches, the study also pointed out the feasibility of crop height estimation using single-baseline RVoG inversion schemes, provided the appropriate a priori constraints (e.g., on the extinction coefficient) and crop-specific configuration parameters (e.g., C-Band for maize, and C- and X-Bands for wheat).
Auteurs: Manuele Pichierri;Irena Hajnsek;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1727 - 1741
Editeur: IEEE
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» Comparison Between Output CM Chokes for SiC Drive Operating at 20- and 200-kHz Switching Frequencies
Résumé:
The adoption of silicon carbide (SiC) MOSFETs in variable speed drives (VSDs) makes it possible to increase the inverter switching frequency up to several hundred kilohertz without incurring excessive inverter loss. As a result, the harmonic currents and related losses in the machine can be significantly reduced, and the dynamic performance of motor will also be improved. However, the high switching frequency will increase the common mode (CM) electromagnetic interference (EMI) emission of the drive system presenting new challenges on CM choke design. In the literature, chokes designed for VSDs operating above 100 kHz are rarely found. Hence, this paper presents a case study on the output CM chokes for a SiC-based VSD switching at 20 and 200 kHz. A comprehensive comparison is made between the chokes for two switching frequencies regarding design, sizing, and performance, through both calculation and experiments. The results show that the CM choke designed for 200 kHz switching frequency is significantly larger and heavier than the 20 kHz choke, due to the higher inductance value required to meet the EMI limit and the lower permeability of the core material. Meanwhile, the 200 kHz choke is also less effective in noise attenuation as a result of the larger winding capacitance compared with the 20 kHz choke.
Auteurs: Di Han;Casey T. Morris;Woongkul Lee;Bulent Sarlioglu;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2178 - 2188
Editeur: IEEE
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» Compartmental and Data-Based Modeling of Cerebral Hemodynamics: Nonlinear Analysis
Résumé:
Objective: As an extension to our study comparing a putative compartmental and data-based model of linear dynamic cerebral autoregulation (CA) and CO2-vasomotor reactivity (VR), we study the CA–VR process in a nonlinear context. Methods: We use the concept of principal dynamic modes (PDM) in order to obtain a compact and more easily interpretable input–output model. This in silico study permits the use of input data with a dynamic range large enough to simulate the classic homeostatic CA and VR curves using a putative structural model of the regulatory control of the cerebral circulation. The PDM model obtained using theoretical and experimental data are compared. Results: It was found that the PDM model was able to reflect accurately both the simulated static CA and VR curves in the associated nonlinear functions (ANFs). Similar to experimental observations, the PDM model essentially separates the pressure-flow relationship into a linear component with fast dynamics and nonlinear components with slow dynamics. In addition, we found good qualitative agreement between the PDMs representing the dynamic theoretical and experimental CO2-flow relationship. Conclusion: Under the modeling assumption and in light of other experimental findings, we hypothesize that PDMs obtained from experimental data correspond with passive fluid dynamical and active regulatory mechanisms. Significance: Both hypothesis-based and data-based modeling approaches can be combined to offer some insight into the physiological basis of PDM model obtained from human experimental data. The PDM modeling approach potentially offers a practical way to quantify the status of specific regulatory mechanisms in the CA–VR process.
Auteurs: Brandon Christian Henley;Dae C. Shin;Rong Zhang;Vasilis Z. Marmarelis;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 1078 - 1088
Editeur: IEEE
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» Compensating XPM Using a Low-Bandwidth Phase Modulator
Résumé:
We experimentally demonstrate, for the first time, cross-phase modulation (XPM) compensation using an optical phase modulator and low-bandwidth electronics. We first show that our nonlinearity compensator suppresses the XPM distortion from a 10-Gb/s ON-OFF keyed (OOK) channel on a continuous-wave (CW) probe signal. We then replace the CW tone with a 28-Gbaud quadrature phase-shift keyed (QPSK) signal and show that the OOK power can be doubled when XPM compensation is used. This demonstrates proof-of-concept for XPM compensation using phase modulators placed along a fiber link.
Auteurs: Benjamin Foo;Bill Corcoran;Arthur Lowery;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 699 - 702
Editeur: IEEE
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» Compensation of Transmitter I/Q Imbalance in Millimeter-Wave SC-FDE Systems
Résumé:
Due to imperfect analog processing, millimeter-wave communication is confronted with severe radio frequency impairments, such as in-phase/quadrature (IQ) imbalance. The presence of I/Q imbalance introduces image interference to the desired signal and can significantly degrade the performance if not compensated. In this paper, we propose a novel training-based compensation method for transmitter (TX) I/Q imbalance in millimeter-wave single carrier with frequency domain equalization (SC-FDE) systems. The novelty of the proposed method is that it can obtain the separate estimates of the TX I/Q imbalance and multipath channel. With the obtained estimates, we can easily conduct the FDE and compensate for the TX I/Q imbalance by simple operations. Simulations show that the proposed method can accurately estimate the TX I/Q imbalance and multipath channel and, thus, can achieve almost the same performance as the ideal case free of TX I/Q imbalance.
Auteurs: Xiantao Cheng;Zengqiang Luo;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4472 - 4476
Editeur: IEEE
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» Completion Time in Two-User Channels: An Information-Theoretic Perspective
Résumé:
Consider a multi-user channel, where each user has a large but non-replenishable bit pool to transmit. Completion time refers to the number of channel uses spent by each user to complete its transmission. In this paper, an information-theoretic formulation of completion time is based on the concept of constrained rates, which are defined over possibly different number of channel uses. Analogous to the capacity region, the completion time region characterizes all possible trade-offs among users’ completion times. For a two-user multi-access channel, it is shown that the completion time region is achieved by operating the channel in two independent phases: a multi-access phase when both users are transmitting, and a point-to-point phase when one user has finished and the other is still transmitting. Using a similar two-phase approach, the completion time regions (or inner and outer bounds) are established for a two-user Gaussian broadcast channel and a two-user Gaussian interference channel. It is observed that although consisting of two convex subregions, the completion time region may not be convex in general. Finally, optimization problems of minimizing the weighted sum completion time for a Gaussian multi-access channel and a Gaussian broadcast channel are solved, demonstrating the utility of the completion time approach.
Auteurs: Yuanpeng Liu;Elza Erkip;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3209 - 3223
Editeur: IEEE
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» Complex-Network-Inspired Design of Traffic Generation Patterns in Communication Networks
Résumé:
In this brief, we consider a generic type of communication network consisting of two kinds of nodes, i.e., hosts and routers, and only the hosts can generate and receive packets. In this kind of network, the traffic performance is closely related to the traffic generation pattern, which strongly depends on the hosts' locations. We employ a simulated annealing algorithm to find a near-optimal configuration of the hosts, which effectively balances the traffic loads and improves the overall traffic performance. Our study suggests that the traffic generation pattern is an important factor for communication network design.
Auteurs: Jiajing Wu;Yongxiang Xia;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 590 - 594
Editeur: IEEE
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» Comprehensive Peak-Shaving Solutions for Port Cranes
Résumé:
This paper discusses the reduction of the maximum power demand of shore-to-ship cranes from the supply power system by the implementation of ultracapacitors and flywheels that locally store up and compensate a rate of the power demand, and by a power optimization tool that shaves the maximum peak of a cranes’ group, coordinating their duty cycles. These reductions can lead to reduced electrical infrastructure system resulting installation and operating expenses for operating shore-ship cranes. The concept presented in the paper is encouraging port facilities developments and modernization to make sustainable microgrids based upon four (l) pillars using leveled, less, local, and load (lele-lolo).
Auteurs: Giuseppe Parise;Luigi Parise;Andrea Malerba;Francesco Maria Pepe;Alberto Honorati;Peniamin Ben Chavdarian;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 1799 - 1806
Editeur: IEEE
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» Compressed FEC Codes With Spatial-Coupling
Résumé:
An error floor problem is observed for a spatially coupled sparse-regression (SCSR) code with limited sparsity in low-to-medium rates. This letter presents a scheme that also involves spatial-coupling and compressed-sensing (SCCS) similar to SCSR. We replace position modulation in SCSR by a general concatenated forward error control code. We introduce a chaining principle that improves the error floor behavior of the underlying code. We show that SCCS based on chained Hadamard codes can offer significantly improved performance.
Auteurs: Chulong Liang;Junjie Ma;Li Ping;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 987 - 990
Editeur: IEEE
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» Computation Time Analysis of the Magnetic Gear Analytical Model
Résumé:
This paper focuses on the computation time and precision of a linear 2-D magnetic gear analytical model. Two main models of magnetic gears are studied: 1) the first with an infinite relative permeability of yokes and 2) the second with a finite relative permeability of yokes. These models are based on the subdomain resolution of Laplace and Poisson equations. To accurately compute the magnetic field distribution, it is necessary to take into account certain harmonics of the various rings and other system harmonics due to modulation. Global system harmonics, which increase the value of computation time, must also be taken into account. If the magnetic gear has a high pole number, then computation time increases even more and no longer allows for system optimization. This paper proposes to compute magnetic field distribution using different harmonic selection methods in order to significantly reduce the computation time for the magnetic torque without any loss of accuracy.
Auteurs: Melaine Desvaux;Benjamin Traullé;Roman Le Goff Latimier;Stéphane Sire;Bernard Multon;Hamid Ben Ahmed;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 9
Editeur: IEEE
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» Computational Depth Sensing : Toward high-performance commodity depth cameras
Résumé:
Depth information plays an important role in a variety of applications, including manufacturing, medical imaging, computer vision, graphics, and virtual/augmented reality (VR/AR). Depth sensing has thus attracted sustained attention from both academia and industry communities for decades. Mainstream depth cameras can be divided into three categories: stereo, time of flight (ToF), and structured light. Stereo cameras require no active illumination and can be used outdoors, but they are fragile for homogeneous surfaces. Recently, off-the-shelf light field cameras have demonstrated improved depth estimation capability with a multiview stereo configuration. ToF cameras operate at a high frame rate and fit time-critical scenarios well, but they are susceptible to noise and limited to low resolution [3]. Structured light cameras can produce high-resolution, high-accuracy depth, provided that a number of patterns are sequentially used. Due to its promising and reliable performance, the structured light approach has been widely adopted for three-dimensional (3-D) scanning purposes. However, achieving real-time depth with structured light either requires highspeed (and thus expensive) hardware or sacrifices depth resolution and accuracy by using a single pattern instead.
Auteurs: Zhiwei Xiong;Yueyi Zhang;Feng Wu;Wenjun Zeng;
Apparue dans: IEEE Signal Processing Magazine
Date publication: 05.-2017, volume: 34, issue:3, pages: 55 - 68
Editeur: IEEE
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» Computational Design and Fabrication
Résumé:
Computer graphics research is increasingly interested in the high-level analysis and processing of geometric objects. By acquiring a structural or functional understanding of 3D shapes, researchers are able to tackle mid- to high-level design problems for which machine computations can replace or at least relieve human efforts. In parallel, with the rapid advances in 3D printing technologies, many design solutions explored by researchers and practitioners are focusing on the needs and constraints arising from physical fabrication. The contributions in this special issue are cross-disciplinary, connecting physical fabrication with design and processing tasks in new domains including circuit design, geospatial visualization, and 3D scanning, leading to never-before-seen 3D printing applications.
Auteurs: Bedrich Benes;David J. Kasik;Wilmot Li;Hao Zhang;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 32 - 33
Editeur: IEEE
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» Computationally Efficient Adjustment of FACTS Set Points in DC Optimal Power Flow With Shift Factor Structure
Résumé:
Enhanced utilization of the existing transmission network is a cheaper and paramount alternative to building new transmission lines. Flexible ac transmission system (FACTS) devices are advanced technologies that offer transfer capability improvements via power flow control. Although many FACTS devices exist in power systems, their set points are not frequently changed for power flow control purposes, which is mainly due to the computational complexity of incorporating FACTS flexibility within the market problem. This paper proposes a computationally efficient method for adjustment of variable impedance-based FACTS set points, which is also compatible with existing market solvers. Thus, the method can be employed by the existing solvers with minimal modification efforts. This paper models FACTS reactance control as injections to keep the initial shift factors unchanged. Next, the paper formulates a dc optimal power flow that co-optimizes FACTS set points alongside generation dispatch. The resulting problem, which is in a nonlinear program, is then reformulated to a mixed-integer linear program. Finally, an engineering insight is leveraged to further reduce the computational complexity to a linear program. Simulation studies on IEEE 118-bus and Polish 2383-bus test cases show that the method is extremely effective in finding quality solutions and being very fast.
Auteurs: Mostafa Sahraei-Ardakani;Kory W. Hedman;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1733 - 1740
Editeur: IEEE
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» Computerized Dungeons and Randomly Generated Worlds: From Rogue to Minecraft
Résumé:
Replayability is a major factor in the long-term enjoyment of a video game. Many games can be engrossing on the first playthrough, but those with fixed solutions and singular paths through multiple levels of skill can quickly lose their appeal after the first win. One approach to replayability is randomly generated content, which ensures a different playthrough each time. While numerous role-playing games simulate dice rolls, procedural generation in games used predefined seed values in combination with pseudorandom number generators to create entire levels and item sets. Rogue is one of the earliest examples of games to focus core gameplay elements around randomly generated levels and items, and its popularity within the UNIX community led to a group of dedicated fans making their own improvements on the game and sharing their modifications online. These derivatives of Rogue, known as “roguelikes,” have more than a 30-year history of development, and many are still maintained to this day.
Auteurs: Nathan Brewer;
Apparue dans: Proceedings of the IEEE
Date publication: 05.-2017, volume: 105, issue:5, pages: 970 - 977
Editeur: IEEE
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» Concentrated Winding IPM Synchronous Motor Design for Wide Field Weakening Applications
Résumé:
In order to understand the impact that certain design changes may have on the performance over a wide speed range, a series of 12-slot 8-pole concentrated winding interior permanent magnet synchronous motors (IPMSMs) are analyzed. Fundamental theory of operation is used to describe the desirable characteristics in terms of the lumped parameters, and finite element analysis is carried out to show how these characteristics may be realized through the motor geometry changes. The motor geometry changes aim to create an IPMSM design with high d-axis inductance for the wide speed range operation, low harmonic content in the back electromotive force waveform, and low cogging torque. A prototype is constructed and test results are presented for verification.
Auteurs: Mohammad Sedigh Toulabi;John Salmon;Andrew M. Knight;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 1892 - 1900
Editeur: IEEE
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» Condensable Supersonic Jet Facility for Analyses of Transient Low-Temperature Gas Kinetics and Plasma Chemistry of Hydrocarbons
Résumé:
LEMPUS-2 facility is designed and built to study processes of cluster formation and plasma-chemical reactions that include atoms, molecules, and clusters, in supersonic jets. The facility is equipped with modern diagnostics tools and molecular-beam, electron-beam, mass-spectrometer, spectrometer, and laser systems for testing and fine-tuning technological processes in a laboratory environment. One of the key advantages of the discussed facility is that in a single system and a single experiment, it combines the tools for the activation of transient and steady-state supersonic flow with self-sustaining or nonself-sustaining discharge, and flow analysis using electron-beam spectroscopy and molecular-beam mass spectroscopy. Dry roughing and high-vacuum pumps enable accurate diagnostics of chemically reacting processes in virtually any gas mixture, including hydrocarbons. A pulsed flow regime controlled by developed in-house fast valves provides an efficient way to examine quasi-stationary flows at fairly high flow rates, with significant material and energy savings. The facility serves a number of purposes, from cluster-surface interaction studies with thin film and surface structure formation, to high-pressure jet expansions that emulate spacecraft nozzles at high altitudes, to technological process development, primarily focused on hydrocarbons. Details of key applications of the facility are presented that include the gas dynamics of cluster jets, the formation of heterogeneous clusters, the study of plasma-chemistry of hydrocarbons, and the thin film deposition.
Auteurs: A. E. Zarvin;V. V. Kalyada;V. Zh. Madirbaev;N. G. Korobeishchikov;M. D. Khodakov;A. S. Yaskin;V. E. Khudozhitkov;S. F. Gimelshein;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 819 - 827
Editeur: IEEE
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» Conference Report on 2016 IEEE Symposium Series on Computational Intelligence (IEEE SSCI 2016) [Conference Reports]
Résumé:
Presents information on the IEEE SSCI 2016 Conference.
Auteurs: Yaochu Jin;Stefanos Kollias;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 05.-2017, volume: 12, issue:2, pages: 18 - 19
Editeur: IEEE
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» Confidence Estimates in Simulation of Phase Noise or Spectral Density
Résumé:
In this paper, we apply the method of discrete simulation of power-law noise, developed by Timmer and König, Ashby, and Ashby and Patla, to the problem of simulating phase noise for a combination of power-law noises. We derive analytic expressions for the probability of observing a value of phase noise $ {mathcal{ L}}(f)$ or of any of the one-sided spectral densities $S_{phi }(f), S_{y}(f)$ , or $S_{x}(f)$ , for arbitrary superpositions of power-law noise.
Auteurs: Neil Ashby;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 872 - 878
Editeur: IEEE
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» Connecting a City by Wireless Backhaul: 3D Spatial Channel Characterization and Modeling Perspectives
Résumé:
The backhaul forwards aggregated traffic from massive users, machines, and sensors to the core network, and is the key infrastructure to facilitate a smart city. The beamforming and spatial multiplexing technologies enable the wireless multipoint-to-point backhaul to connect dense small cell eNodeBs (eNBs) and macrocell eNBs. Because the spatial characteristics of the backhaul channels, such as the angular power spectra and spreads, determine the interference and capacity performance of the backhaul links, accurate 3D channel modeling is vital for the evaluation and comparison of candidate proposals. In this article, the concepts and methodology of spatial channel modeling are first introduced, and the state-of-the-art models developed by the standardization bodies in recent years are surveyed. Then we present a field measurement campaign on the 3D backhaul channels in an urban street, including the channel sounder implementation, field measurement, multipath parameter estimation, and propagation modeling. The Rx of the sounder (emulating a donor eNB) was installed on the rooftop of a five-story building, and the Tx was located along a street and at different altitudes to emulate a relay eNB. The channel angular power spectra in the elevation and azimuth domains were measured, and the impact by the relay�s distance and altitude on the angular spreads was evaluated. In addition, a Laplace model is proposed for the power spectra in both domains. This article not only explains the methodology and implementation of the spatial channel measurement, but also reveals the urban wireless backhaul channel characteristics which are useful for the design and deployment of wireless backhaul for a smart city.
Auteurs: Ruonan Zhang;Xiaohong Jiang;Tarik Taleb;Bin Li;Heng Qin;Zhimeng Zhong;Xiaomei Zhang;
Apparue dans: IEEE Communications Magazine
Date publication: 05.-2017, volume: 55, issue:5, pages: 62 - 69
Editeur: IEEE
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» Considerations for Dependability of the Motor Protection on Current Transformers Performance in VFD Applications
Résumé:
When generators or motors are started via variable frequency drive (VFD), initial frequency is very low, on the order of few hertz, and can be low for a considerable amount of time or even permanently. It is not well recognized in the industry about the consequences of low frequency on current transformers (CTs) performance and how this affects the protection performance as well. First, CTs are designed to operate at the nominal system frequency; however, when operating at low frequency, CTs could saturate at much lower currents; this can happen even at CT nominal current. Second, there are limits of the system frequency measurements in the protective relays, which will impact the correct current magnitude estimation, and therefore, the accuracy of the protection. And finally, protective relays need full power-cycle to measure current; power-cycle will be considerably longer at lower frequency, therefore affecting fault clearance time. This paper will educate engineers on how to consider CTs and protective relay's performance at lower frequencies to ensure adequate protection. It will also explore other solutions to address impact of low frequency on the CTs and protection.
Auteurs: Umar Khan;Ilia Voloh;Patrick Robinson;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2635 - 2641
Editeur: IEEE
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» Constrained Turbo Product and Block-Convolutional Codes in Wireless Applications
Résumé:
Constrained interleavers are used in constrained turbo product codes (CTPCs) and constrained turbo block-convolutional (CTBC) codes. The constrained interleaver delivers an interleaver gain close to uniform interleaving while also increasing the minimum Hamming distance. In this study, new and improved single row (SR) versions of the previous codes, called SR-CTPCs and SR-CTBC codes, are introduced that have higher interleaver gain, better performance, and much more flexible frame sizes as needed in wireless applications. Compared with the WiMax and the long-term evolution standards, it is demonstrated that SR-CTPC and SR-CTBC codes perform better than those currently used in the wireless standards.
Auteurs: Yuan Hu;John P. Fonseka;Yu Bo;Eric M. Dowling;Murat Torlak;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4491 - 4495
Editeur: IEEE
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» Constraint Screening for Security Analysis of Power Networks
Résumé:
Consider a general security-constrained unit commitment (SCUC) problem for an arbitrary power network. This problem includes discrete variables corresponding to commitment parameters as well as demand and generation constraints, among others. Aside from its nonconvexity, SCUC is a large-scale problem for real-world systems due to the security constraints. The main objective of this paper is to propose an algorithm to eliminate a vast majority of linear security constraints in the high-dimensional mixed-integer SCUC problem in order to arrive at an equivalent reduced-order SCUC problem. To this end, we develop a parallel and computationally cheap algorithm for finding a minimal subset of security constraints whose satisfaction guarantees the satisfaction of all security constraints. The proposed algorithm does not depend on the unknown unit commitment parameters and allows the load forecasts to be imprecise. More specifically, a low-order model of the SCUC problem is found based on the topology of the power system, given lower and upper bounds on nodal power injections (to accommodate uncertainties in loads and generation productions), and the normal and emergency line ratings. This algorithm is tested on several power systems with as many as 5500 buses, for which each set of security constraints with millions of conditions is reduced to a minimal subset with only a few hundred conditions.
Auteurs: Ramtin Madani;Javad Lavaei;Ross Baldick;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1828 - 1838
Editeur: IEEE
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» Construction of MDS Codes With Complementary Duals
Résumé:
A linear complementary dual (LCD) code is a linear code with complimentary dual. LCD codes have been extensively studied in literature. On the other hand, maximum distance separable (MDS) codes are an important class of linear codes that have found wide applications in both theory and practice. However, little is known about MDS codes with complimentary duals. The main purpose of this paper is to construct several classes of MDS codes with complimentary duals, i.e., LCD MDS codes, through generalized Reed-Solomon codes.
Auteurs: Lingfei Jin;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2843 - 2847
Editeur: IEEE
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» Construction of Voronoi Diagram using the Hollow Sphere Concept
Résumé:
This paper implements an algorithm for constructing Voronoi regions using the method we call "hollow sphere". This principle uses the circle, sphere or hyper-sphere as a geometric structure taking into account an Euclidean space of an arbitrary dimension. Boris Deloné used the property of the empty circle to build the Delaunay triangulation; in our case, the same property is used to perform the validations of the hollow spheres, but without using triangles as a fundamental structure. For convenience sake, the hollow sphere as a circle so as to work in two dimensions will be explained and illustrated. However, there is no impediment to working with spheres to take the principles to a three-dimensional space. Furthermore, the properties of the hollow sphere are detailed and an algorithm of incremental construction is used with O(nlogn) time.
Auteurs: Netz Romero;Ricardo Barron;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 950 - 958
Editeur: IEEE
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» Contact-Force Control of a Flexible Timoshenko Arm in Rigid/Soft Environment
Résumé:
This technical note discusses a contact-force control problem of a one-link flexible arm. This flexible arm includes a Timoshenko beam, and thus we call it the flexible Timoshenko arm. The primary aim is to control the contact force at the contact point. To do so, we first apply our previously proposed force controller, which exponentially stabilizes the closed-loop system of a flexible Euler-Bernoulli arm, to the force-control problem of the flexible Timoshenko arm. We then show that our previously proposed force controller cannot exponentially stabilize the flexible Timoshenko arm. Next, we consider the flexible Timoshenko arm, which is making contact with a soft environment. By utilizing the damping force in the soft environment, as well as the controller, we try to overcome the problem. We then prove the exponential stability of the closed-loop system. Finally, we provide simulation results, and consider the validity of our force controller.
Auteurs: Takahiro Endo;Minoru Sasaki;Fumitoshi Matsuno;Yingmin Jia;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2546 - 2553
Editeur: IEEE
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» Content Ecosystem: Serving Diverse Interests in Our Community [From the Editor]
Résumé:
Presents the introductory editorial for this issue of the publication.
Auteurs: Min Wu;
Apparue dans: IEEE Signal Processing Magazine
Date publication: 05.-2017, volume: 34, issue:3, pages: 3 - 13
Editeur: IEEE
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» Continuous Top-k Monitoring on Document Streams
Résumé:
The efficient processing of document streams plays an important role in many information filtering systems. Emerging applications, such as news update filtering and social network notifications, demand presenting end-users with the most relevant content to their preferences. In this work, user preferences are indicated by a set of keywords. A central server monitors the document stream and continuously reports to each user the top-k documents that are most relevant to her keywords. Our objective is to support large numbers of users and high stream rates, while refreshing the top-k results almost instantaneously. Our solution abandons the traditional frequency-ordered indexing approach. Instead, it follows an identifier-ordering paradigm that suits better the nature of the problem. When complemented with a novel, locally adaptive technique, our method offers (i) proven optimality w.r.t. the number of considered queries per stream event, and (ii) an order of magnitude shorter response time (i.e., time to refresh the query results) than the current state-of-the-art.
Auteurs: Leong Hou U;Junjie Zhang;Kyriakos Mouratidis;Ye Li;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 05.-2017, volume: 29, issue:5, pages: 991 - 1003
Editeur: IEEE
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» Continuous-Time Marginal Pricing of Electricity
Résumé:
The current practice of discrete-time electricity pricing starts to fall short in providing an accurate economic signal reflecting the continuous-time variations of load and generation schedule in power systems. This paper introduces the fundamental mathematical theory of continuous-time marginal electricity pricing. We first formulate the continuous-time unit commitment problem as a constrained variational problem, and subsequently define the continuous-time economic dispatch (ED) problem where the binary commitment variables are fixed to their optimal values. We then prove that the continuous-time marginal electricity price equals to the Lagrange multiplier of the variational power balance constraint in the continuous-time ED problem. The proposed continuous-time marginal price is not only dependent to the incremental generation cost rate, but also to the incremental ramping cost rate of the units, thus embedding the ramping costs in calculation of the marginal electricity price. The numerical results demonstrate that the continuous-time marginal price manifests the behavior of the constantly varying load and generation schedule in power systems.
Auteurs: Masood Parvania;Roohallah Khatami;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1960 - 1969
Editeur: IEEE
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» Control of a Direct Matrix Converter With Modulated Model-Predictive Control
Résumé:
This paper investigates the use of a model-predictive control strategy to control a direct matrix converter. The proposed control method combines the features of the classical model-predictive control and the space vector modulation technique into a modulated model-predictive control. This new solution maintains all the characteristics of model-predictive control (such as fast transient response, multiobjective control using only one feedback loop, easy inclusion of nonlinearities and constraints of the system, and the flexibility to include other system requirements in the controller), adding the advantages of working at fixed switching frequency and improving the quality of the controlled waveforms. Simulation and experimental results employing the control method to a direct matrix converter are presented.
Auteurs: Manjusha Vijayagopal;Pericle Zanchetta;Lee Empringham;Liliana de Lillo;Luca Tarisciotti;Patrick Wheeler;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2342 - 2349
Editeur: IEEE
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» Control of a Grid-Forming Inverter Based on Sliding-Mode and Mixed ${H_2}/{H_infty }$ Control
Résumé:
A grid-forming inverter (GFI) is an important component for the operation of an islanded microgrid. Its purpose, similar to a conventional slack bus generator, is to build up a reference voltage for other distributed generating units in the microgrid. Usually, a nested-loop proportional plus integral (PI) control structure is employed to control a GFI in a $dq$ reference frame. However, conventional PI-based nested-loop control method has a deteriorative performance under parameter variations. In this paper, a novel nested-loop control strategy is proposed for control of a GFI system containing an ${LC}$ output filter and loads. The proposed method does not require a precise model for the inverter system and can better deal with uncertainties and ${LC}$ filter resonance without using any passive or active damping mechanisms. It utilizes a sliding-mode control in the inner current loop and a mixed ${H_2}/{H_infty }$ optimal control in the outer voltage loop, which provides the advantages of constant switching frequency, low total harmonic distortion, robustness against parameters variations, and fast transient response. The simulation and hardware experiments presented in this paper demonstrate the proposed controller's improved transient and steady-state performance in various key criteria, over conventional PI-based nested-loop control strategy.
Auteurs: Zhongwen Li;Chuanzhi Zang;Peng Zeng;Haibin Yu;Shuhui Li;Jing Bian;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3862 - 3872
Editeur: IEEE
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» Control of Modular Multilevel Converters Under Singular Unbalanced Voltage Conditions With Equal Positive and Negative Sequence Components
Résumé:
This paper focuses on the control of Modular Multilevel Converters (MMC) for High Voltage DC (HVDC) applications during unbalanced AC grid voltage sags where positive and negative sequence voltages are equal. The control scheme is based on six arm energy regulators, six independent current controllers, and two reference calculation stages that convert the power references into grid and inner current references. Conventional inner AC currents reference calculation fails if the amplitude of the positive and the negative sequence AC grid voltages are equal, a state which is referred to in this paper as singular voltage condition. This paper discusses the types of network faults that cause this condition and proposes three different solutions to operate the converter in such scenarios. The adequacy of the proposed solutions is validated through simulations considering each of the problematic fault scenarios.
Auteurs: Eduardo Prieto-Araujo;Adrià Junyent-Ferré;Gerard Clariana-Colet;Oriol Gomis-Bellmunt;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2131 - 2141
Editeur: IEEE
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» Control of Uncertain Sampled-Data Systems: An Adaptive Posicast Control Approach
Résumé:
This technical note proposes a discrete-time adaptive controller for the control of sampled-data systems. The design is inspired from the Adaptive Posicast Controller (APC) which was designed for time-delay systems in continuous time. Due to the performance degradation caused by digital approximation of continuous laws, together with the problem of assuming time-delays as integer multiples of sampling intervals, the benefits of APC could not be fully realized. In this technical note, these approximations/assumptions are eliminated. In addition, a disturbance observer is incorporated into the controller design which minimizes the effect of disturbances on the system. Extension to the case of uncertain input time-delay is also presented. The proposed approach is verified in simulation studies.
Auteurs: Khalid Abidi;Yildiray Yildiz;Anuradha Annaswamy;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2597 - 2602
Editeur: IEEE
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» Control With Minimal Cost-Per-Symbol Encoding and Quasi-Optimality of Event-Based Encoders
Résumé:
We consider the problem of stabilizing a continuous-time linear time-invariant system subject to communication constraints. A noiseless finite-capacity communication channel connects the process sensors to the controller/actuator. The sensor's state measurements are encoded into symbols from a finite alphabet, transmitted through the channel, and decoded at the controller/actuator. We suppose that the transmission of each symbol costs one unit of communication resources, except for one special symbol in the alphabet that is “free” and effectively signals the absence of transmission. We explore the relationship between the encoder's average bit-rate, its average consumption of communication resources, and the ability of the controller and encoder/decoder pair to stabilize the process. We present a necessary and sufficient condition for the existence of a stabilizing controller and encoder/decoder pair, which depends on the encoder's average bit-rate, its average resource consumption, and the unstable eigenvalues of the process. Moreover, if this condition is satisfied, a stabilizing encoding scheme can be constructed that consumes resources at an arbitrarily small rate, provided the encoder has access to a sufficiently precise clock or large memory. The paper concludes with the analysis of a simple emulation-based controller and event-based encoder/decoder pair that are easy to implement, stabilize the process, and have average bit-rate and resource consumption within a constant factor of the optimal bound.
Auteurs: Justin Pearson;João P. Hespanha;Daniel Liberzon;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2286 - 2301
Editeur: IEEE
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» Convergence and State Reconstruction of Time-Varying Multi-Agent Systems From Complete Observability Theory
Résumé:
We study continuous-time consensus dynamics for multi-agent systems with undirected switching interaction graphs. We establish a necessary and sufficient condition for exponential asymptotic consensus based on the classical theory of complete observability. The proof is remarkably simple compared to similar results in the literature and the conditions for consensus are mild. This observability-based method can also be applied to the case where negatively weighted edges are present. Additionally, as a by-product of the observability based arguments, we show that the nodes' initial value can be recovered from the signals on the edges up to a shift of the network average.
Auteurs: Brian D. O. Anderson;Guodong Shi;Jochen Trumpf;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2519 - 2523
Editeur: IEEE
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» Convex Space Building Discretization for Ray-Tracing
Résumé:
This paper describes a point-to-multipoint 3-D convex space-based ray-tracing technique. This visibility list is calculated and stored and can be reused as needed. What distinguishes our method is that the visibility list is transmitter location-independent, is a 3-D implementation, and is highly computationally efficient. The division of the building into free and filled convex spaces leads to an efficient Method of Images reflection and diffraction path generation algorithm. This technique can be used to optimize the locations of base transceivers in a highly efficient manner. The first step in producing this tool is the generation of efficient ray-tracing algorithms. The ray-tracing algorithm was specifically designed for later incorporation into a transmitter optimization algorithm. This requires a fast ray-tracing method because of its computationally intensive needs—running multiple times over a point-to-multipoint grid. Our algorithm is executed for sample building environments and then for a real building and compared with measurements to confirm its validity. It is clear that the results are in good agreement but do indicate that a highly accurate spatial modeling of the building is required.
Auteurs: Eamonn M. Kenny;Eamonn O. Nuallain;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2578 - 2591
Editeur: IEEE
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» Cooperative Caching and Transmission Design in Cluster-Centric Small Cell Networks
Résumé:
Wireless content caching in small cell networks (SCNs) has recently been considered as an efficient way to reduce the data traffic and the energy consumption of the backhaul in emerging heterogeneous cellular networks. In this paper, we consider a cluster-centric SCN with combined design of cooperative caching and transmission policy. Small base stations (SBSs) are grouped into disjoint clusters, in which in-cluster cache space is utilized as an entity. We propose a combined caching scheme, where part of the cache space in each cluster is reserved for caching the most popular content in every SBS, while the remaining is used for cooperatively caching different partitions of the less popular content in different SBSs, as a means to increase local content diversity. Depending on the availability and placement of the requested content, coordinated multi-point technique with either joint transmission or parallel transmission is used to deliver content to the served user. Using Poisson point process for the SBS location distribution and a hexagonal grid model for the clusters, we provide analytical results on the successful content delivery probability of both transmission schemes for a user located at the cluster center. Our analysis shows an inherent tradeoff between transmission diversity and content diversity in our cooperation design. We also study the optimal cache space assignment for two objective functions: maximization of the cache service performance and the energy efficiency. Simulation results show that the proposed scheme achieves performance gain by leveraging cache-level and signal-level cooperation and adapting to the network environment and user quality-of-service requirements.
Auteurs: Zheng Chen;Jemin Lee;Tony Q. S. Quek;Marios Kountouris;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3401 - 3415
Editeur: IEEE
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» Cooperative Caching Placement in Cache-Enabled D2D Underlaid Cellular Network
Résumé:
In a cache-enabled D2D underlaid cellular network, cooperation of BS caching and D2D caching can further exploit the limited storage capacity and achieve more efficient wireless resource utilization. In this complex network scenario, the closed form expression for successful transmission probability is firstly derived using stochastic geometry, to measure the proportion of users satisfying the delay guarantee. On this basis, a cooperative caching placement problem is formulated to maximize the successful transmission probability. We prove it can be transformed equivalently into a biconvex problem and then a block coordinate descent based algorithm is proposed. Simulation results demonstrate the performance gain of the proposed cooperative caching placement.
Auteurs: Yue Wang;Xiaofeng Tao;Xuefei Zhang;Yu Gu;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1151 - 1154
Editeur: IEEE
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» Cooperative Source Node Tracking in Non-Line-of-Sight Environments
Résumé:
The accuracy of localization is highly degraded in indoor and harsh environments where source nodes either do not have connections with a sufficient number of anchor nodes due to strong attenuation or have very poor range estimates due to NLOS propagation. Cooperative localization is a technique in which the source nodes communicate not only with the anchor nodes, but also with each other. Hence, the source nodes can collect several additional measurements which significantly improve the localization performance. Although many studies have examined NLOS-degraded localization of a static node in noncooperative networks, and many others have examined the impact of cooperation for static localization, there is no work which considers cooperative tracking of mobile nodes. To address this open problem, in this work, we examine cooperative tracking, particularly in NLOS environments. More specifically, we develop a novel sensor tracking algorithm based on semidefinite programming (SDP) which has the ability to mitigate NLOS propagation. Our simulations show that the new SDP-based tracking algorithm outperforms the classic extended Kalman filter as well as the other recently proposed algorithms for noncooperative tracking in NLOS environments. We also show that the algorithm can be extended to cooperative networks, and that a substantial performance benefit is realized by cooperation.
Auteurs: Reza Monir Vaghefi;R. Michael Buehrer;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1287 - 1299
Editeur: IEEE
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» Coordinated Control of Offshore Wind Farm and Onshore HVDC Converter for Effective Power Oscillation Damping
Résumé:
Damping contribution from wind farms (WFs) is likely to become a mandatory requirement as a part of the grid codes. For remote offshore WFs, connected through a voltage source converter (VSC)-based direct current link, the most convenient option for the onshore transmission system operator (TSO) is to modulate the reactive power at the onshore VSC within their own jurisdiction. In this paper, we show that supplementary control through the onshore VSC alone, although attractive for TSOs, could result in undesirable voltage variations in the onshore grid. On the other hand, modulation of active power output of the wind turbine generators (WTG) alone turns out to be inadequate due to the limited overload capability of the WTGs. Coordinated control over both onshore VSC and aggregated WF output overcomes the above limitations and is shown to be effective for power oscillation damping. A homotopy approach is used to design the coordinated controller, which can be implemented locally (at offshore WF and onshore converter site) using a decentralized architecture. This is a bilinear matrix inequality problem, which is solved by transforming these constraints into linear matrix inequality constraints. Case studies on two test systems show that the proposed controller yields similar system dynamic response as supplementary control through the WF alone.
Auteurs: Yousef Pipelzadeh;Nilanjan Ray Chaudhuri;Balarko Chaudhuri;Tim C. Green;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1860 - 1872
Editeur: IEEE
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» Correction to “Flux Control Range Broadening and Torque Ripple Minimization of a Double Excitation Synchronous Motor”
Résumé:
In [1], an error in Fig. 2 in Section II-B is corrected. In the original figure, Fig. 2(b) was exactly the same as Fig. 2(a). The correction is shown here.
Auteurs: K. Hoang;L. Vido;M. Gabsi;F. Gillon;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 1
Editeur: IEEE
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» Corrections to “Impacts of Strategic Bidding of Wind Power Producers on Electricity Markets”
Résumé:
Auteurs: Mohsen Banaei;Majid Oloomi Buygi;Hamidreza Zareipour;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2489 - 2489
Editeur: IEEE
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» Corrections to “De Novo Annotation of Transposable Elements: Tackling the Fat Genome Issue” [Jamilloux et al., Proc. IEEE, vol. 105, no. 3, pp. 474–481, Mar. 2017, DOI: 10.1109/JPROC.2016.2590833]
Résumé:
In [1], Fig. 1 is inconsistent with the text manuscript. First, the black curve corresponding to case 1 did not correspond to the result from the experiment described in the paper, but to another which was removed from the final manuscript. The second error was a typo with an inversion between the green and blue text indicating NTE50 and LTE50 for cases 4 and 5, respectively. We corrected this figure for the case 1 curve with the right experimental result, and fixed the typo so that it corresponds now perfectly with the manuscript text. Note that this does not affect the text in the manuscript, which remains correct.
Auteurs: Véronique Jamilloux;Josquin Daron;Frédéric Choulet;Hadi Quesneville;
Apparue dans: Proceedings of the IEEE
Date publication: 05.-2017, volume: 105, issue:5, pages: 978 - 978
Editeur: IEEE
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» Corrections to “A 3-D Assembled Silicon-Embedded Transformer for 10-MHz, Ultra-High-Isolation, Compact Chip-to-Chip Power Transfer”
Résumé:
In the above paper [1], the seventh reference “R. Wu, J. K. O. Sin, and S. Y. Hui, ‘A novel silicon-embedded coreless transformer for isolated DC-DC converter application,’ in Proc. IEEE 23rd Int. Symp. Power Semiconductor Devices ICs, Hong Kong, China, May 2015, pp. 297–300, doi: 10.1109/ISPSD.2011.5890863” is incorrect. The correct reference is “R. Wu, N. Liao, X. Fang, and J. K. O. Sin, ‘A novel 3D transformer for ultra-compact signal isolation,’ in Proc. IEEE 27th Int. Symp. Power Semiconductor Devices ICs, Hong Kong, China, May 2015, pp. 297-300, doi: 10.1109/ISPSD.2015.7123448.”
Auteurs: Rongxiang Wu;Niteng Liao;Xiangming Fang;Jian Cai;Qian Wang;Johnny K. O. Sin;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 689 - 689
Editeur: IEEE
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» Corrections to “Crosstalk-Canceling Multimode Interconnect Using Transmitter Encoding”
Résumé:
The authors of [1] would like to note the following corrections in reference numbering. It is difficult to find correct references in the currently published paper due to the reference discords.
Auteurs: HoonSeok Kim;Chanyoun Won;Paul D. Franzon;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1792 - 1792
Editeur: IEEE
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» Corrections to “Information Without Rolling Dice”
Résumé:
In the paper above [1], published in the March 2017 issue of the IEEE Transactions on Information Theory, the following changes are noted.

In the Abstract, page 1349, left column, line 3, “using square-integrable and bandlimited signals” should be replaced by “using square-integrable, bandlimited signals.”

Auteurs: Taehyung J. Lim;Massimo Franceschetti;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3332 - 3332
Editeur: IEEE
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» Corrections to “Interconnect Design and Benchmarking for Charge-Based Beyond-CMOS Device Proposals”
Résumé:
In the above-named paper [ibid., vol. 37, no. 4, pp. 508–511, Apr. 2016], a typo was found in equation 3. The corrected equation is provided.
Auteurs: Chenyun Pan;Azad Naeemi;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 690 - 690
Editeur: IEEE
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» Corrections to “Lower Bounds on Q for Finite Size Antennas of Arbitrary Shape”
Résumé:
Equations (24) and (25) in [1, Appendix B] should, respectively, read as begin{align*}&hspace {-2pc}int nolimits _{V_infty }-(nabla G_{1}) G_{2}^{*} - {hat {boldsymbol {r}}} jkfrac {e^{jk( {boldsymbol {r}}_{1}- {boldsymbol {r}}_{2})cdot {hat {boldsymbol {r}}} }}{16pi ^{2}| {boldsymbol {r}}|^{2}} {dV} =-frac { {boldsymbol {r}}_{12}}{| {boldsymbol {r}}_{12}|}frac {cos (k| {boldsymbol {r}}_{12}|)}{8pi } notag \&-, jfrac {2 {boldsymbol {r}}_{1}}{8pi k^{2}}left ({ frac {sin (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|^{3}}-frac {kcos (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|^{2}} }right )notag \&-, jfrac {| {boldsymbol {r}}_{1}|^{2}-| {boldsymbol {r}}_{2}|^{2}}{8pi k^{2}}frac { {boldsymbol {r}}_{12}}{| {boldsymbol {r}}_{12}|^{2}}notag \× left ({ frac {k^{2}sin (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|}- 3left ({frac {sin (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|^{3}}-frac {kcos (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|^{2}} }right )}right ) end{align*} and begin{align*}&hspace {-2pc}int nolimits _{V_infty } j(nabla G_{1}) G_{2}^{*} - {hat {boldsymbol {r}}} kfrac {e^{jk( {boldsymbol {r}}_{1}- {boldsymbol {r}}_{2})cdot {hat {boldsymbol {r}}} }}{16pi ^{2}| {boldsymbol {r}}|^{2}} {dV} =jfrac { {boldsymbol {r}}_{12}}{| {boldsymbol {r}}_{12}|}frac {cos (k| {boldsymbol {r}}_{12}|)}{8pi } \&{-} frac { {boldsymbol {r}}_{12}}{8pi k^{2}}left ({ frac {sin (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|^{3}}-frac {kcos (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|^{2}} }right ) \&{-} frac { {boldsymbol {r}}_{1}+ {boldsymbol {r}}_{2}}{8pi k^{2}}left ({ frac {sin (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|^{3}}-frac {kcos (k| {boldsymb- l {r}}_{12}|)}{| {boldsymbol {r}}_{12}|^{2}} }right ) \&{-} frac {| {boldsymbol {r}}_{1}|^{2}-| {boldsymbol {r}}_{2}|^{2}}{8pi k^{2}}frac { {boldsymbol {r}}_{12}}{| {boldsymbol {r}}_{12}|^{2}} \× left ({ frac {k^{2}sin (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|}-3left ({frac {sin (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|^{3}}-frac {kcos (k| {boldsymbol {r}}_{12}|)}{| {boldsymbol {r}}_{12}|^{2}} }right )}right ) \=&jfrac { {boldsymbol {r}}_{12}}{2} text {Re}{G_{12}}-frac {1}{2 k^{2}} text {Im}{nabla _{1} G_{12}} \&{-}frac { {boldsymbol {r}}_{1}+ {boldsymbol {r}}_{2}}{2 k^{2}} text {Im}left {{nabla _{1} G_{12}cdot frac { {boldsymbol {r}}_{12}}{| {boldsymbol {r}}_{12}|^{2}}}right } \&{+}frac {| {boldsymbol {r}}_{1}|^{2}-| {boldsymbol {r}}_{2}|^{2}}{2k^{2}| {boldsymbol {r}}_{12}|^{2}} text {Im}{ {boldsymbol {r}}_{12}k^{2}G_{12}+3nabla _{1} G_{12}}. end{align*}
Auteurs: Oleksiy S. Kim;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2773 - 2773
Editeur: IEEE
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» Cost Optimal Integration of Flexible Buildings in Congested Distribution Grids
Résumé:
Buildings are candidates for providing flexible demand due to their high consumption and inherent thermal inertia. In the future, flexible demand side reserves may also help to relax the expected higher reserve requirements of the grid due to the presence of renewables. However, this flexible demand might be vulnerable to price signals, as the simultaneous increase in consumption by multiple buildings due to low (high) energy (reserves) price periods might cause congestion in distribution grids. In order to integrate congestion-free energy and reserve provision from buildings, this paper presents two benchmark pricing methodologies: (1 ) distribution locational marginal prices (DLMP), and (2) iterative DLMP (iDLMP). Both methods deploy convex optimization to obtain an optimal solution of the original problem. Using dual decomposition, a settlement scheme, which efficiently distributes the congestion cost among involved participants, is also presented. Case studies are performed on a benchmark distribution system along with the National Energy Market Singapore's price framework. The results prove that both methods optimally remove congestion from distribution grids and have potential to be integrated into the theoretical framework of liberalized markets. Furthermore, as a comparison, it is shown that the DLMP-based prices outperforms existing pricing structures of the distribution grid. Hence, using this scheme, the distribution system operator can evaluate existing tariffs and introduce incentives for price responsive demands. However, to support these methods, the high requirement for information sharing in the DLMP method and/or communication technology infrastructure for calculating iDLMPs must exist in the future grid.
Auteurs: Sarmad Hanif;Tobias Massier;Hoay Beng Gooi;Thomas Hamacher;Thomas Reindl;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2254 - 2266
Editeur: IEEE
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» Cost-Efficient Placement of Communication Connections for Transmission Line Monitoring
Résumé:
For overhead transmission line monitoring, wireless sensor networks offer a low-cost solution to connect sensors on towers with the control center. However, these networks cannot meet stringent quality of service (QoS) requirements, in terms of packet delivery ratio and delay. Also, it is necessary to ensure robustness such that data can be delivered when a tower fails. In view of the QoS and robustness requirements, wide area network (WAN) connections, such as cellular and satellite network are needed, on top of wireless sensor networks. Different WAN connections have different characteristics in terms of availability, performance, and cost. We have proposed a novel scheme, called optimal placement for QoS and robustness (OPQR), which uses the canonical genetic algorithm to determine the numbers, locations, and types of WAN connections to be deployed to minimize cost while satisfying the QoS and robustness requirements. Evaluation results confirm that OPQR can indeed fulfil the desired requirements at minimum cost, and it is a very useful tool in cost-efficient communication network planning for transmission line monitoring. Specifically, OPQR can maintain cost below USD50 per day for a transmission line that has 80 towers spanning across 32 km, while maintaining the packet delay below 100 ms, packet delivery ratio above 99.99%, and each flow has two node-disjoint paths to the control center.
Auteurs: Peng-Yong Kong;Chih-Wen Liu;Joe-Air Jiang;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4058 - 4067
Editeur: IEEE
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» CRIL: An Efficient Online Adaptive Indoor Localization System
Résumé:
Indoor localization or indoor positioning systems find their use in many important applications such as augmented reality, guided tours, tracking and monitoring, and situational awareness and have recently attracted intense research interests. Previous localization systems are usually received signal strength indication (RSSI)-based, inertial navigation system (INS)-based, or an integration of these two. However, few of them can account for dynamic communication environments, where channel states constantly change. To the best of our knowledge, this paper is the first to propose an efficient and adaptive indoor localization system called coupled RSSI and INS localization (CRIL), which can adapt to dynamic communication environments quickly and effectively. Moreover, CRIL can account for the uncertainties in RSSI measurements such as varying covariances and outliers as well. Extensive simulation results demonstrate that our proposed CRIL system is able to track both slow changes and sudden changes of the channel states in dynamic environments. Noticeably, the proposed CRIL can perform accurate localization with estimation errors up to $text{1} , mathrm{m}$, while previous schemes’ localization errors are up to several meters or even tens of meters. Moreover, we test CRIL in real experiments, and its localization error is up to 3 m in dynamic environments.
Auteurs: Sheng Cai;Weixian Liao;Changqing Luo;Ming Li;Xiaoxia Huang;Pan Li;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4148 - 4160
Editeur: IEEE
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» Cross-Correlated Contrast Source Inversion
Résumé:
In this paper, we improved the performance of the contrast source inversion (CSI) method by incorporating a so-called cross-correlated cost functional, which interrelates the state error and the data error in the measurement domain. The proposed method is referred to as the cross-correlated CSI. It enables better robustness and higher inversion accuracy than both the classical CSI and multiplicative regularized CSI (MR-CSI). In addition, we show how the gradient of the modified cost functional can be calculated without significantly increasing the computational burden. The advantages of the proposed algorithms are demonstrated using a 2-D benchmark problem excited by a transverse magnetic wave as well as a transverse electric wave, respectively, in comparison with classical CSI and MR-CSI.
Auteurs: Shilong Sun;Bert Jan Kooij;Tian Jin;Alexander G. Yarovoy;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2592 - 2603
Editeur: IEEE
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» Cross-Layer Rate Control and Resource Allocation in Spectrum-Sharing OFDMA Small-Cell Networks With Delay Constraints
Résumé:
In this paper, we present a dynamic resource management scheme for delay-aware applications in two-tier small-cell networks (SCNs). We propose the scheme of joint rate control at the transport layer and resource allocation at the physical layer to manage the cross-tier interference. The joint rate control and resource allocation scheme is designed to maximize the time-averaged sum capacity of small cell users in the SCN subject to each small cell user's delay constraint and an interference constraint imposed by the macrocell. By using the Lyapunov optimization technique, we develop a delay-guaranteed capacity optimal algorithm (DCOA) to obtain the optimal rate control and resource allocation decisions. We show that without prior knowledge of the data arrivals and channel statistics, DCOA achieves a capacity of SCN that can arbitrarily approach the optimal capacity achieved by the algorithm with the complete knowledge of data arrivals and channel statistics. Simulations results confirm the theoretical analysis on the performance of DCOA and also show the adaptiveness of DCOA.
Auteurs: Yashuang Guo;Qinghai Yang;Jiayi Liu;Kyung Sup Kwak;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4133 - 4147
Editeur: IEEE
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» Cross-Network Performance Analysis of Network Coding Aided Cooperative Outband D2D Communications
Résumé:
In long term evolution advanced (LTE-A) networks, the mobile devices can concurrently participate in cooperative outband device-to-device (D2D) data exchange by virtue of user- or network-related parameters (e.g., interest in the same content and cooperative transmissions, respectively). In these scenarios, two major problems arise: 1) the coexistence of multiple devices creates channel access issues, demanding effective medium access control (MAC) schemes, and 2) cellular network factors (i.e., scheduling policy and channel conditions) affect the D2D communication, as the circulating information in D2D links is mainly of cellular network origination, stressing the need for cross network approaches. In this context, the contribution of this paper is threefold. First, exploiting idle devices as relays and the benefits of network coding (NC) in bidirectional communications, we propose an adaptive cooperative NC-based MAC (ACNC-MAC) protocol for the D2D data exchange. Then, we devise a cross-network model that captures the impact of cellular network characteristics on D2D communication. Finally, we evaluate the performance of the ACNC-MAC in terms of throughput, energy efficiency, and battery consumption. Our results show that the LTE-A parameters and the relays’ participation significantly affect the D2D throughput, while the D2D performance deteriorates with the increase of cell congestion.
Auteurs: Eftychia Datsika;Angelos Antonopoulos;Nizar Zorba;Christos Verikoukis;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3176 - 3188
Editeur: IEEE
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» Cross-Scale Cost Aggregation for Stereo Matching
Résumé:
This paper proposes a generic framework that enables a multiscale interaction in the cost aggregation step of stereo matching algorithms. Inspired by the formulation of image filters, we first reformulate cost aggregation from a weighted least-squares (WLS) optimization perspective and show that different cost aggregation methods essentially differ in the choices of similarity kernels. Our key motivation is that while the human stereo vision system processes information at both coarse and fine scales interactively for the correspondence search, state-of-the-art approaches aggregate costs at the finest scale of the input stereo images only, ignoring inter-consistency across multiple scales. This motivation leads us to introduce an inter-scale regularizer into the WLS optimization objective to enforce the consistency of the cost volume among the neighboring scales. The new optimization objective with the inter-scale regularization is convex, and thus, it is easily and analytically solved. Minimizing this new objective leads to the proposed framework. Since the regularization term is independent of the similarity kernel, various cost aggregation approaches, including discrete and continuous parameterization methods, can be easily integrated into the proposed framework. We show that the cross-scale framework is important as it effectively and efficiently expands state-of-the-art cost aggregation methods and leads to significant improvements, when evaluated on Middlebury, Middlebury Third, KITTI, and New Tsukuba data sets.
Auteurs: Kang Zhang;Yuqiang Fang;Dongbo Min;Lifeng Sun;Shiqiang Yang;Shuicheng Yan;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 05.-2017, volume: 27, issue:5, pages: 965 - 976
Editeur: IEEE
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» Crossbar-Based Memristive Logic-in-Memory Architecture
Résumé:
The use of memristors and resistive random access memory (ReRAM) technology to perform logic computations, has drawn considerable attention from researchers in recent years. However, the topological aspects of the underlying ReRAM architecture and its organization have received less attention, as the focus has mainly been on device-specific properties for functionally complete logic gates through conditional switching in ReRAM circuits. A careful investigation and optimization of the target geometry is thus highly desirable for the implementation of logic-in-memory architectures. In this paper, we propose a crossbar-based in-memory parallel processing system in which, through the heterogeneity of the resistive cross-point devices, we achieve local information processing in a state-of-the-art ReRAM crossbar architecture with vertical group-accessed transistors as cross-point selector devices. We primarily focus on the array organization, information storage, and processing flow, while proposing a novel geometry for the cross-point selection lines to mitigate current sneak-paths during an arbitrary number of possible parallel logic computations. We prove the proper functioning and potential capabilities of the proposed architecture through SPICE-level circuit simulations of half-adder and sum-of-products logic functions. We compare certain features of the proposed logic-in-memory approach with another work of the literature, and present an analysis of circuit resources, integration density, and logic computation parallelism.
Auteurs: Georgios Papandroulidakis;Ioannis Vourkas;Angel Abusleme;Georgios Ch. Sirakoulis;Antonio Rubio;
Apparue dans: IEEE Transactions on Nanotechnology
Date publication: 05.-2017, volume: 16, issue:3, pages: 491 - 501
Editeur: IEEE
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» Crosstalk and Ghost Gratings in a Large-Scale Weak Fiber Bragg Grating Array
Résumé:
Large-scale distributed fiber Bragg grating (FBG) sensor networks have a wide range of applications. However, serious crosstalk could occur in a near-identical serial FBG sensor network because of multiple reflections. Since crosstalk cannot be observed directly and separately from signal, experimental investigation of crosstalk is challenging. In this work, we point out the similarity and symmetry between crosstalk and ghost gratings, and by way of measuring the spectrum of ghost gratings, we experimentally study the characteristics of crosstalk in a serial array of 3010 near-identical FBGs using a commercial FBG sensor interrogation system. We show that ghost gratings drop much more rapidly in power as one goes downstream, and they are more homogeneous in spectral distribution than real gratings. The peak wavelengths of real gratings vary within ±100 pm while the peak wavelengths of the ghost gratings they generate vary within ±20 pm only. Spectral ripples are observed for ghost gratings and real gratings severely affected by crosstalk. These ripples reduce the FBG wavelength reading accuracy to ±5 pm. The work constitutes the first experimental study on crosstalk in large-scale FBG arrays.
Auteurs: Huiyong Guo;Li Qian;Ciming Zhou;Zhou Zheng;Yinquan Yuan;Ruquan Xu;Desheng Jiang;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 2032 - 2036
Editeur: IEEE
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» Current Status and Opportunities of Organic Thin-Film Transistor Technologies
Résumé:
Attributed to its advantages of super mechanical flexibility, very low-temperature processing, and compatibility with low cost and high throughput manufacturing, organic thin-film transistor (OTFT) technology is able to bring electrical, mechanical, and industrial benefits to a wide range of new applications by activating nonflat surfaces with flexible displays, sensors, and other electronic functions. Despite both strong application demand and these significant technological advances, there is still a gap to be filled for OTFT technology to be widely commercially adopted. This paper provides a comprehensive review of the current status of OTFT technologies ranging from material, device, process, and integration, to design and system applications, and clarifies the real challenges behind to be addressed.
Auteurs: Xiaojun Guo;Yong Xu;Simon Ogier;Tse Nga Ng;Mario Caironi;Andrea Perinot;Ling Li;Jiaqing Zhao;Wei Tang;Radu A. Sporea;Ahmed Nejim;Jordi Carrabina;Paul Cain;Feng Yan;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 1906 - 1921
Editeur: IEEE
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» Current-Voltage Model for Negative Capacitance Field-Effect Transistors
Résumé:
In this letter, a semi-analytical current–voltage model for a negative capacitance field-effect transistor (NCFET) with a ferroelectric material (i.e., BaTiO3) is proposed. Surface potential ( $psi _{mathrm {S}})$ in the channel region is determined first by solving the Landau–Khalatnikov (LK) equation numerically with Poisson’s equation. Then, the drain–current is achieved based on the current continuity equation using $psi _{mathrm {S}}$ determined earlier. In addition, by introducing a fitting potential for a given drain–voltage, threshold voltage shift can be captured, resulting in accurate surface potential and drain–current at different gate voltages. We have verified our model using the technology computer-aided design (TCAD)-MATLAB simulation, and our model exhibits an excellent agreement to the simulation results. In addition, the impacts of the ferroelectric thickness and channel doping concentration on the device performance and hysteresis window of NCFET are thoroughly explored.
Auteurs: Hyunjae Lee;Youngki Yoon;Changhwan Shin;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 669 - 672
Editeur: IEEE
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» Custom Multicache Architectures for Heap Manipulating Programs
Résumé:
Memory-intensive implementations often require access to an external, off-chip memory which can substantially slow down an field-programmable gate array accelerator due to memory bandwidth limitations. Buffering frequently reused data on chip is a common approach to address this problem and the optimization of the cache architecture introduces yet another complex design space. This paper presents a high-level synthesis (HLS) design aid that automatically generates parallel multicache systems which are tailored to the specific requirements of the application. Our program analysis identifies nonoverlapping memory regions, supported by private caches, and regions which are shared by parallel units after parallelization, which are supported by coherent caches and synchronization primitives. It also decides whether the parallelization is legal with respect to data dependencies. The novelty of this paper is the focus on programs using dynamically allocated, pointer-based data structures which, while common in software engineering, remain difficult to analyze and are beyond the scope of the overwhelming majority of HLS techniques to date. Second, we devise a high-level cache performance estimation to find a heterogeneous configuration of cache sizes that maximizes the performance of the multicache system subject to an on-chip memory resource constraint. We demonstrate our technique with three case studies of applications using dynamic data structures and use Xilinx Vivado HLS as an exemplary HLS tool. We show up to $boldsymbol {15}boldsymbol {times }$ speed-up after parallelization of the HLS implementations and the insertion of the application-specific distributed hybrid multicache architecture.
Auteurs: Felix Winterstein;Kermin E. Fleming;Hsin-Jung Yang;George A. Constantinides;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 761 - 774
Editeur: IEEE
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» Cyber Meets Control: A Novel Federated Approach for Resilient CPS Leveraging Real Cyber Threat Intelligence
Résumé:
Cyber-physical systems (CPS) embody a tight integration between network-based communications, software, sensors, and physical processes. While the integration of cyber technologies within legacy systems will most certainly introduce opportunities and advancements not yet envisioned, it will undoubtedly also pave the way to misdemeanors that will exploit systems� resources, causing drastic and severe nationwide impacts. While almost all works in the literature exclusively tackled the security of one independent aspect of CPS (i.e., cyber or physical), we argue that these systems cannot be decoupled. In this context, we present what we believe is a first attempt ever to tackle the problem of CPS security in a coupled and a systematic manner. To this end, this article proposes a novel approach that federates the cyber and physical environments to infer and attribute tangible CPS attacks. This is achieved by - Leveraging real cyber threat intelligence derived from empirical measurements. - Capturing and investigating CP data flows by devising an innovative CPS threat detector. An added value of the proposed approach is rendered by physical remediation strategies, which are envisioned to automatically be invoked as a reaction to the inferred attacks to provide CPS resiliency. We conclude this article by discussing a few design considerations and presenting three case studies that demonstrate the feasibility of the proposed approach.
Auteurs: Elias Bou-Harb;Walter Lucia;Nicola Forti;Sean Weerakkody;Nasir Ghani;Bruno Sinopoli;
Apparue dans: IEEE Communications Magazine
Date publication: 05.-2017, volume: 55, issue:5, pages: 198 - 204
Editeur: IEEE
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» Cylindrical Plasmonic Waveguides With Cladding of Hyperbolic Metamaterials
Résumé:
We propose and analyze a new design of cylindrical plasmonic waveguides with the dielectric-coated metal wire as the inner core structure and the hyperbolic metamaterial as the outer cladding. The propagation characteristics of the plasmonic waveguides are analytically solved based on the dispersion relation of a multilayered anisotropic structure in cylindrical coordinates. By using the hyperbolic cladding on the core structure, a sufficiently confined mode area comparable to that of the metal cladding can be attained, while the propagation length is substantially increased. This character is attributed to the strong anisotropy of the hyperbolic cladding that offers an extra degree of freedom to adjust the balance between confinement and loss, leading to a better waveguide performance. A significantly improved figure of merit (the ratio of propagation length to mode size) is achieved for the plasmonic waveguides made of silver and zinc oxide at the telecommunication wavelength.
Auteurs: Ruey-Lin Chern;Ming-Chih Tsai;You-Zhong Yu;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1995 - 2002
Editeur: IEEE
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» Cylindrical Polarimetric Phased Array Radar: Beamforming and Calibration for Weather Applications
Résumé:
Future weather radar systems will need to provide rapid updates within a flexible multifunctional overall radar network. This naturally leads to the use of electronically scanned phased array antennas. However, the traditional multifaced planar antenna approaches suffer from having radiation patterns that are variant in both beam shape and polarization as a function of electronic scan angle; even with practically challenging angle-dependent polarization correction, this places limitations on how accurately weather can be measured. A cylindrical array with commutated beams, on the other hand, can theoretically provide patterns that are invariant with respect to azimuth scanning with very pure polarizations. This paper summarizes recent measurements of the cylindrical polarimetric phased array radar demonstrator, a system designed to explore the benefits and limitations of a cylindrical array approach to these future weather radar applications.
Auteurs: Caleb Fulton;Jorge L. Salazar;Yan Zhang;Guifu Zhang;Redmond Kelly;John Meier;Matt McCord;Damon Schmidt;Andrew D. Byrd;Lal Mohan Bhowmik;Shaya Karimkashi;Dusan S. Zrnic;Richard J. Doviak;Allen Zahrai;Mark Yeary;Robert D. Palmer;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2827 - 2841
Editeur: IEEE
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» Damage Modeling of a Low-Noise Amplifier in an RF Front-End Induced by a High Power Electromagnetic Pulse
Résumé:
The RF front-end is a very vulnerable part of the coupling paths that are induced by a high power electromagnetic (HPEM) pulse. Existing studies found through experiment or simulation that low-noise amplifiers (LNAs) often break down or are damaged, which causes the malfunction of the RF front-end. To protect the RF front-end, the damage process of LNAs based on theory is required in detail. This paper summarizes the damage process, and a new library is developed describing the damage phenomenon of LNAs by using user-defined elements. The model can be combined with other circuit models, and can also offer variation of the internal parameters of LNAs by HPEM pulse. Existing physical protection methods have high costs and complexity, and it is difficult to provide perfect protection. Thus, the proposed model can contribute to protection studies utilizing a circuit model.
Auteurs: Ji-Eun Baek;Young-Maan Cho;Kwang-Cheol Ko;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 798 - 804
Editeur: IEEE
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» Damped-SOGI-Based Control Algorithm for Solar PV Power Generating System
Résumé:
This paper deals with two-stage solar photovoltaic (PV) system with a damped-second-order generalized integrator (SOGI) algorithm. Proposed topology not only integrates the PV energy to the grid, in addition, it provides the load compensation, power factor correction, and harmonics elimination. Therefore, a double stage system is proposed where the first stage is a dc–dc boost converter, which performs the maximum power point tracking by regulating its duty ratio. For extracting maximum power from the PV array, an incremental conductance-based approach is utilized. Moreover, in the next stage, a voltage source converter (VSC) is utilized. To control the VSC, a damped-SOGI algorithm is used. By using a damped-SOGI-based control algorithm, fundamental active components of load currents are extracted for evaluating the reference grid currents. After comparing reference grid currents with sensed grid currents, switching pulses for the grid tied VSC are produced. A prototype of the proposed system is developed in the laboratory and test results are presented for verification of control of solar photovoltaic system.
Auteurs: Bhim Singh;Shailendra Kumar;Chinmay Jain;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 1780 - 1788
Editeur: IEEE
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» Damping Nomogram Method for Small-Signal Security Assessment of Power Systems
Résumé:
This paper reviews the main concepts about power systems security assessment and describes the voltage security assessment (VSA), the transient security assessment (TSA) and the small-signal security assessment (SSA) of electrical power systems. Most methods of SSA are based on the calculation of oscillation modes of power systems and the evaluation of their damping factors. The objective of the power system security assessment is to determine the distance that these systems are to certain security boundary. In small-signal security assessment case, the security limits are, in general, associated to a minimum secure damping factor of the oscillation modes. This paper proposes a nomogram method based on the analysis of oscillation damping factors to be used for small-signal security assessment of power systems and describes its computational development.
Auteurs: Thiago Jose Masseran Antunes Parreiras;Sergio Gomes Junior;Glauco Nery Taranto;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 877 - 883
Editeur: IEEE
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» Dangers of Distractions [Electrical Safety]
Résumé:
Examines the impact distractions have on industrial electrical safety. Workers and their supervisors are constantly interrupted during their work. If you spend any time at an industrial facility, you know that paging systems and calls on mobile devices are in constant use and make it hard to concentrate. At sites with limited resources, the electrical workers may have other extended responsibilities beyond the job at hand.
Auteurs: Daniel Doan;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 05.-2017, volume: 23, issue:3, pages: 5 - 72
Editeur: IEEE
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» Data Perturbation-Based Sensitivity Analysis of Real-Time Look-Ahead Economic Dispatch
Résumé:
In this paper, the sensitivity of look-ahead economic dispatch in real-time power markets with respect to data perturbation is studied. In the look-ahead dispatch optimization problem, a small change in the data that are used for setting the interspatial and temporal equality/inequality constraints and the objective function may negatively affect normal operations, such as the calculation of real-time wholesale electricity prices and operating costs. This could lead to more distorted prices and larger operating costs with the look-ahead dispatch than with a static dispatch that use data for a single future time. We perturb Karush–Kuhn–Tucker conditions of the look-ahead dispatch optimization formulation and then, using them, derive a linear sensitivity matrix that assesses the impact of data corruption on look-ahead dispatch. This matrix illustrates the changing optimal solution of look-ahead dispatch subject to potential corruption in various types of spatial and temporal data—generator's bidding cost coefficients, capacity limits for generators and transmission lines, ramp rates and the estimate of initial generation output with ramp constraints, and multiple-time series of the forecast load for the look-ahead horizon. The results of the simulation are illustrated with numerical examples in the IEEE 14-bus system.
Auteurs: Dae-Hyun Choi;Le Xie;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2072 - 2082
Editeur: IEEE
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» Data-Assisted Modeling and Speed Control of a Robotic Fish
Résumé:
In this paper, a novel data-assisted dynamical modeling and control approach is developed for robotic fish speed tracking. The data-assisted modeling focuses on the thrust mechanism, including the structure and parameters that are absent from the Newtonian-based analytic model of the robotic motion. The thrust of a robotic fish is generated through undulatory body movement interacting with surrounding water, thus a consequence of reaction from environmental hydrodynamics. It is known, however, that hydrodynamics cannot be analytically modeled. Thus, the data-assisted modeling is necessary for an underwater robotic fish. Specifically in this work, data of pulse and step responses are collected from designated experimental trials, in which the pulse responses are used to determine the thrust delay terms, and step responses are used to build up the thrust nonlinearity at steady state. A discrete-time sliding mode controller (SMC) is constructed to perform speed control. The experimental results verify that an SMC with a data-assisted model can substantially improve the speed control performance of two-dimensional robotic motion.
Auteurs: Saurab Verma;Jian-Xin Xu;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4150 - 4157
Editeur: IEEE
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» Data-Based Optimal Control for Networked Double-Layer Industrial Processes
Résumé:
This paper investigates the data-based optimal control for a class of networked industrial processes with a double-layer architecture. Without knowing the dynamics of subsystems at the device layer, the index prediction function is constructed via the input/output signals, and radial basis function neural networks. The tuning laws for the index prediction function are obtained through the optimal control strategy. Then, by treating the network-induced phenomenon as random round-trip time delay and introducing the predictive algorithm, the compensation scheme is designed at the operation layer to dynamically decompose the setpoints. Finally, two simulation examples are given to further illustrate the effectiveness of the proposed compensation strategy.
Auteurs: Jianbin Qiu;Tong Wang;Shen Yin;Huijun Gao;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4179 - 4186
Editeur: IEEE
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» Data-Driven Adaptive Optimal Control of Connected Vehicles
Résumé:
In this paper, a data-driven non-model-based approach is proposed for the adaptive optimal control of a class of connected vehicles that is composed of $n$ human-driven vehicles only transmitting motional data and an autonomous vehicle in the tail receiving the broadcasted data from preceding vehicles by wireless vehicle-to-vehicle (V2V) communication devices. Considering the cases of range-limited V2V communication and input saturation, several optimal control problems are formulated to minimize the errors of distance and velocity and to optimize the fuel usage. By employing an adaptive dynamic programming technique, the optimal controllers are obtained without relying on the knowledge of system dynamics. The effectiveness of the proposed approaches is demonstrated via the online learning control of the connected vehicles in Paramics' traffic microsimulation.
Auteurs: Weinan Gao;Zhong-Ping Jiang;Kaan Ozbay;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1122 - 1133
Editeur: IEEE
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» Data-Driven Control and Learning Systems
Résumé:
Auteurs: Zhongsheng Hou;Huijun Gao;Frank L. Lewis;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4070 - 4075
Editeur: IEEE
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» Data-Driven Optimal Consensus Control for Discrete-Time Multi-Agent Systems With Unknown Dynamics Using Reinforcement Learning Method
Résumé:
This paper investigates the optimal consensus control problem for discrete-time multi-agent systems with completely unknown dynamics by utilizing a data-driven reinforcement learning method. It is known that the optimal consensus control for multi-agent systems relies on the solution of the coupled Hamilton–Jacobi–Bellman equation, which is generally impossible to be solved analytically. Even worse, most real-world systems are too complicated to obtain accurate mathematical models. To overcome these deficiencies, a data-based adaptive dynamic programming method is presented using the current and past system data rather than the accurate system models also instead of the traditional identification scheme which would cause the approximation residual errors. First, we establish a discounted performance index and formulate the optimal consensus problem via Bellman optimality principle. Then, we introduce the policy iteration algorithm which motivates this paper. To implement the proposed online action-dependent heuristic dynamic programming method, two neural networks (NNs), 1) critic NN and 2) actor NN, are employed to approximate the iterative performance index functions and control policies, respectively, in real time. Finally, two simulation examples are provided to demonstrate the effectiveness of the proposed method.
Auteurs: Huaguang Zhang;He Jiang;Yanhong Luo;Geyang Xiao;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4091 - 4100
Editeur: IEEE
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» Data-Driven Robust Output Tracking Control for Gas Collector Pressure System of Coke Ovens
Résumé:
Disturbances, uncertainties, nonlinearity, couplings, and measurement disturbances exist extensively in the coke oven gas collector pressure system (GCPS) and may deteriorate tracking performance. In this paper, a practical method named data-driven robust output tracking control (DROTC) combining advantages of sliding-mode contr-ol (SMC) and data-driven control (DDC) is proposed for stable pressure control of gas collectors of coke ovens. Unlike the conventional DDC approach, the proposed controller is based on SMC framework, where a novel hybrid control structure and a new data-driven sliding surface are developed to facilitate the controller design. On one hand, the couplings, disturbances, and uncertainties are suppressed owing to the application of the SMC technique and the extended state observer. On the other hand, the stability of the DROTC system with bounded measurement disturbances could also be guaranteed by applying the DDC law. Moreover, the robustness could also be ensured once the sliding mode control system enters into the sliding mode. Finally, simulation and experimental results confirm the validity of the proposed control approach.
Auteurs: Yongpeng Weng;Xianwen Gao;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4187 - 4198
Editeur: IEEE
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» DC Motor Speed Control through Parallel DC/DC Buck Converters
Résumé:
This article proposes a multivariable robust controller for the regulation of DC motor angular speed, and for the active current sharing in each parallel DC/DC buck converter. Considering that the parallel DC/DC buck converter is connected in cascade to the armature of the DC motor. Additionally, the controller rejects actively the internal and external disturbances, which is subjected the multivariable linear system. These disturbances are considered time-varying, but they are bounded. The control law is based on differential flatness and active disturbance rejection control with GPI observers. Computer simulations using Matlab/Simulink verified the effectiveness of the proposed controller.
Auteurs: Esteban Guerrero;Jesus Linares;Enrique Guzman;Hebbert Sira;Gerardo Guerrero;Alberto Martinez;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 819 - 826
Editeur: IEEE
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» DC-Assisted Bipolar Switched Reluctance Machine
Résumé:
In this paper, a sinusoidal excited four-phase switched reluctance machine (SRM) with modified dc-assisted windings is presented. The proposed four-phase SRM configuration with modified dc windings has a reduced number of controllable phases and power converter devices. The dc winding configuration is modified from its traditional form by taking advantage of the machine's inherent 90° phase shift between adjacent phases to achieve the desired simplification in the drive. Different power electronic converters for the proposed winding configuration have also been investigated. The proposed concepts are then verified through finite element analysis and an experimental prototype.
Auteurs: Tausif Husain;Yilmaz Sozer;Iqbal Husain;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2098 - 2109
Editeur: IEEE
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» Deadbeat Model-Predictive Torque Control With Discrete Space-Vector Modulation for PMSM Drives
Résumé:
This paper proposes an alternative strategy of finite-control-set model-predictive torque control (MPTC) to reduce the computational burden and the torque ripple and decouple the switching frequency from the controller sampling time. An improved discrete space-vector modulation (DSVM) technique is utilized to synthesize a large number of virtual voltage vectors. The deadbeat (DB) technique is used to optimize the voltage vector selection process, avoiding enumerating all the feasible voltage vectors. With this proposed method, only three voltage vectors are tested in each predictive step. Based on the improved DSVM method, the three candidate voltage vectors are calculated by using a novel algebraic way. This new strategy has the benefits of both the MPTC method and the DB method. The effectiveness of the proposed strategy is validated based on a test bench.
Auteurs: Yuanlin Wang;Xiaocan Wang;Wei Xie;Fengxiang Wang;Manfeng Dou;Ralph M. Kennel;Robert D. Lorenz;Dieter Gerling;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3537 - 3547
Editeur: IEEE
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» Decision-Based System Identification and Adaptive Resource Allocation
Résumé:
System identification extracts information from a system's operational data to derive a representative model for the system so that a decision can be made with desired accuracy and reliability. When resources are limited, especially for networked systems sharing data and communication power and bandwidth, identification must consider complexity as a critical limitation. Focusing on optimal resource allocation under a given reliability requirement, this paper studies identification complexity and its relations to decision making. Dynamic resource assignments are investigated. Algorithms are developed and their convergence properties are established, including strong convergence, almost sure convergence rate, and asymptotic normality. By a suitable design of resource updating step sizes, the algorithms are shown to achieve the CR lower bound asymptotically, and hence are asymptotically efficient. Illustrative examples demonstrate significant advantages of our real-time and individualized resource allocation methodologies over population-based worst-case strategies.
Auteurs: Jin Guo;Biqiang Mu;Le Yi Wang;George Yin;Lijian Xu;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2166 - 2179
Editeur: IEEE
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» Deep Learning Classification of Land Cover and Crop Types Using Remote Sensing Data
Résumé:
Deep learning (DL) is a powerful state-of-the-art technique for image processing including remote sensing (RS) images. This letter describes a multilevel DL architecture that targets land cover and crop type classification from multitemporal multisource satellite imagery. The pillars of the architecture are unsupervised neural network (NN) that is used for optical imagery segmentation and missing data restoration due to clouds and shadows, and an ensemble of supervised NNs. As basic supervised NN architecture, we use a traditional fully connected multilayer perceptron (MLP) and the most commonly used approach in RS community random forest, and compare them with convolutional NNs (CNNs). Experiments are carried out for the joint experiment of crop assessment and monitoring test site in Ukraine for classification of crops in a heterogeneous environment using nineteen multitemporal scenes acquired by Landsat-8 and Sentinel-1A RS satellites. The architecture with an ensemble of CNNs outperforms the one with MLPs allowing us to better discriminate certain summer crop types, in particular maize and soybeans, and yielding the target accuracies more than 85% for all major crops (wheat, maize, sunflower, soybeans, and sugar beet).
Auteurs: Nataliia Kussul;Mykola Lavreniuk;Sergii Skakun;Andrii Shelestov;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 778 - 782
Editeur: IEEE
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» Deep Learning in Automotive Software
Résumé:
Deep-learning-based systems are becoming pervasive in automotive software. So, in the automotive software engineering community, the awareness of the need to integrate deep-learning-based development with traditional development approaches is growing, at the technical, methodological, and cultural levels. In particular, data-intensive deep neural network (DNN) training, using ad hoc training data, is pivotal in the development of software for vehicle functions that rely on deep learning. Researchers have devised a development lifecycle for deep-learning-based development and are participating in an initiative, based on Automotive SPICE (Software Process Improvement and Capability Determination), that's promoting the effective adoption of DNN in automotive software. This article is part of a theme issue on Automotive Software.
Auteurs: Fabio Falcini;Giuseppe Lami;Alessandra Mitidieri Costanza;
Apparue dans: IEEE Software
Date publication: 05.-2017, volume: 34, issue:3, pages: 56 - 63
Editeur: IEEE
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» Degree-Based WCL for Video Endoscopic Capsule Localization
Résumé:
Wireless video capsule endoscope (VCE) is used to diagnose lesions along digestive tracts. For proper diagnosis, it is necessary to know the exact location of the lesions which may be estimated by localizing the VCE. In this paper, we propose a simple VCE localization approach using static and dynamic degree-based weighted centroid localization (WCL). In our proposed approach, a sensor array of eight receivers is used to estimate the distance of the moving capsule. The estimated distance is then raised to a higher degree to reduce the weight of the remote sensors marginally lower. We propose a suboptimal method of both static and dynamic degree calculation using the estimated distances. We also analytically compute the optimal values of the degree to set benchmark to compare the performance of our proposed suboptimal methods. We develop a 3 D simulation platform using MATLAB to show the results and to verify the accuracy. We use indices named localization error (LE), average localization error (ALE), standard deviation (STD) and the normalized error to evaluate the performance. Using static optimal degree, the ALE is 5.19 mm where ALE of 6.55 mm is reachable using the suboptimal method. For dynamic degree, ALE using optimal degree is 3.8 mm, while the ALE using suboptimal degree is 6.27 mm. Thus, our proposed algorithms approach benchmark accuracy even if we change the dimension of the sensor network. The performance is also compared to the existing algorithms in the literature which shows better performance using our proposed algorithms.
Auteurs: Umma Hany;Lutfa Akter;Farhad Hossain;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2904 - 2916
Editeur: IEEE
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» Degrees of Freedom Region of the MIMO $2 times 2$ Interference Network With General Message Sets
Résumé:
We establish the degrees of freedom (DoF) region for the multiple-input multiple-output (MIMO) two-transmitter, and two-receiver ( $2 times 2$ ) interference network with a general message set consisting of nine messages, one for each pair of a subset of transmitters at which that message is known and a subset of receivers where that message is desired. An outer bound on the general nine-message $2 times 2$ interference network is obtained and it is shown to be tight, thereby establishing the DoF region for the most general antenna setting wherein the four nodes have an arbitrary number of antennas each. The DoF-optimal scheme is applicable to the MIMO $2 times 2$ interference network with constant channel coefficients, and hence, a fortiori, to time/frequency varying channel scenarios. In particular, a linear precoding scheme is proposed that can achieve all the DoF tuples in the DoF region. In it, the precise roles played by transmit zero-forcing, interference alignment, random beamforming, symbol extensions, and asymmetric complex signaling (ACS) are delineated. For instance, we identify a class of antenna settings, in which ACS is required to achieve the fractional-valued corner points. Evidently, the DoF regions of all previously unknown cases of the $2 times 2$ interference network with a subset of the nine-messages are newly established as special cases of the general result of this paper. For instance, the DoF region of the well-known four-message (and even three-message) MIMO $X$ channel is newly established. This problem had remained open despite previous studies, which had foun- inner and outer bounds that were not tight in general. Hence, the DoF regions of all special cases obtained from the general DoF region of the nine-message $2times 2$ interference network of this paper that include at least three of the four $X$ channel messages are new, among many others. This paper sheds light on how the same physical $2 times 2$ interference network could be used by a suitable choice of message sets to take most advantage of the channel resource in a flexible and efficient manner.
Auteurs: Yao Wang;Mahesh K. Varanasi;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3259 - 3276
Editeur: IEEE
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» Delay and Power Evaluation of Negative Capacitance Ferroelectric MOSFET Based on SPICE Model
Résumé:
The current evaluation on negative capacitance ferroelectric MOSFET (NC-FeFET) mostly reports device-level current/capacitance-voltage prediction and approaches with ease of integration in SPICE for circuit level performance prediction are very limited. For benchmarking against intrinsic MOSFET and beyond-CMOS devices, a new Landau–Khalatnikov theory-based SPICE model of ferroelectric is presented as a series connection of a voltage controlled voltage source and a resistor. It predicts both static and dynamic behaviors by including ferroelectric damping constant. Integration of this ferroelectric model with BSIM4 model of 45-nm CMOS technology allows prediction of circuit-level performance of NC-FeEFT. In current–voltage characteristics, both subthreshold swing and off-state current are reduced compared with intrinsic MOSFET. For an inverter chain, different values of damping constants give rise to a wide range of propagation delays and power consumptions. Only NC-FeFET using sufficiently low damping constant ferroelectric with similar response time to intrinsic MOSFET can be considered as a low-power device with a similar propagation delay. In this case, its dynamic power is suppressed by the same proportion as that of internal voltage amplification and static leakage power also drops. Our results reveal the ferroelectric switching time and Landau parameter requirements for FeFET use in low-power circuit applications.
Auteurs: Yang Li;Kui Yao;Ganesh S. Samudra;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2403 - 2408
Editeur: IEEE
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» Delay-Aware Flow Scheduling In Low Latency Enterprise Datacenter Networks: Modeling and Performance Analysis
Résumé:
Real-time interactive application workloads (e.g., Web search, social networking, and so on) appear in the form of a large number of mini requests and responses flowing over the datacenters’ networks. They end up being sewed all together to constitute a user-requested task or computation (e.g., display a complete Facebook timeline). Applications as such strictly impose low latency flow completion, since the service’s quality is decreed by quick aggregation of responses to the largest possible fraction of requests and their delivery back to the user. This paper presents a deadline-aware flow scheduling (DAFS). In addition to reducing the average flow completion time (FCT), DAFS aims at decreasing the deadline mismatch and blocking probabilities, hence improving the average application throughput. An analytical queuing model is formulated herein to capture the datacenter’s network dynamics and evaluate its performance when operating under DAFS. The model is validated through extensive simulations whose results also show that DAFS outperforms existing multi-queue-based priority mechanisms by 52% in terms of the average FCT and a range of 7%–29% in terms of the average throughput.
Auteurs: Maurice Khabbaz;Khaled Shaban;Chadi Assi;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 2078 - 2090
Editeur: IEEE
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» Demand Side Management in Microgrids for Load Control in Nearly Zero Energy Buildings
Résumé:
The paper presents a feasible model of architecture for the technical building systems (TBS) particularly suitable for nearly zero energy buildings (NZEBs). The suggested model aggregates the users around an electric node in order to reach up the threshold value of electric power, and to get a more virtuous and flexible cumulative load profile. Present proposal is a full electric common smart micro grid with a single point of connection, with heating and domestic hot water generated by a centralized electric heat pump system. The renewable energy is provided by a photovoltaic field connected to the common grid. A building automation control system operates those electric TBS modulating the global load for a building demand response (DR). The effectiveness of the proposed model consists of exploiting thermal inertia as an energy storage, by forcing both local and central set points of heating and air conditioning systems. The control is based on the integrated and common operation of all users and all systems of the building as one unique “large user.” The integrated management of the grid is operated to control the whole electric demand exploiting the self-consumption, avoiding peaks, and maintaining a flat load profile. The suggested microgrid model allows concretely the possibility to realize a building DR with benefits for the end-users in a consumer view point. A study of the effect of these control opportunities on whole electric demand is done by simulation on a case study.
Auteurs: Luigi Martirano;Emanuele Habib;Giuseppe Parise;Giacomo Greco;Matteo Manganelli;Ferdinando Massarella;Luigi Parise;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 1769 - 1779
Editeur: IEEE
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» Demand-Side Management of Domestic Electric Water Heaters Using Approximate Dynamic Programming
Résumé:
In this paper, two techniques based on ${Q}$ -learning and action dependent heuristic dynamic programming (ADHDP) are demonstrated for the demand-side management of domestic electric water heaters (DEWHs). The problem is modeled as a dynamic programming problem, with the state space defined by the temperature of output water, the instantaneous hot water consumption rate, and the estimated grid load. According to simulation, ${Q}$ -learning and ADHDP reduce the cost of energy consumed by DEWHs by approximately 26% and 21%, respectively. The simulation results also indicate that these techniques will minimize the energy consumed during load peak periods. As a result, the customers saved about $466 and $367 annually by using ${Q}$ -learning and ADHDP techniques to control their DEWHs (100 gallons tank size) operation, which is better than the cost reduction that resulted from using the state-of-the-art ($246) control technique under the same simulation parameters. To the best of the authors’ knowledge, this is the first work that uses the approximate dynamic programming techniques to solve the DEWH’s load management problem.
Auteurs: Khalid Al-jabery;Zhezhao Xu;Wenjian Yu;Donald C. Wunsch;Jinjun Xiong;Yiyu Shi;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 775 - 788
Editeur: IEEE
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» Demodulation Techniques for Self-Oscillating Eddy-Current Displacement Sensor Interfaces: A Review
Résumé:
This paper presents a comprehensive study of demodulation techniques for high-frequency self-oscillating eddy-current displacement sensor (ECDS) interfaces. Increasing the excitation frequency is essential for lowering the skin depth in many demanding industrial applications, that require better resolution. However, a high excitation frequency poses design challenges in the readout electronics, and particularly in the demodulation functional block. We analyze noise, linearity, and stability design considerations in amplitude demodulators for nanometer and sub-nanometer ECDSs. A number of state-of-the-art amplitude demodulation techniques employed in high-frequency ECDSs are reviewed, and their pros and cons are evaluated.
Auteurs: Vikram Chaturvedi;Mohammad Reza Nabavi;Johan G. Vogel;Stoyan Nihtianov;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2617 - 2624
Editeur: IEEE
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» Derived Observations From Frequently Sampled Microwave Measurements of Precipitation. Part II: Sensitivity to Atmospheric Variables and Instrument Parameters
Résumé:
This is the second of two papers that quantify the high added value of frequent 3-D radar observations of the atmosphere to capture the dynamics of weather systems. Recent advances in small-satellite and radar technologies, such as the “Radar in Cubesat” developed at the Jet Propulsion Laboratory, are paving the way for the design of convoys of spaceborne radars that can directly observe the evolution of severe weather at very fine temporal scales. The analyses presented here are to establish the relation between such observations to the underlying cloud variables and processes, and to quantify the sensitivity to the different physical and instrument parameters. In this paper, we quantify the uncertainty in the relation between the measured radar reflectivities Z and their time derivatives dtZ, on one hand, and the underlying rate of change of the condensed-water mass M, and fluxes of dry and moist air in convection, on the other hand. The uncertainties are due to the variability of the atmospheric parameters as well as the constraints of an observation strategy that would use pairs of spaceborne instruments. We specifically analyze the sensitivities for pairs of satellites, each carrying a Ka-band profiling radar. Our simulations show that, with a convoy of two spacecraft separated by ~90 s, each with a pointing accuracy of ~0.025° in rms error, a sensitivity of 17 dBZ and a precision of 1 dBZ, the proposed observation strategy would capture more than 70% of the tropical convection between 5 and 10 km of altitude and resolve the air-mass and condensed-water fluxes.
Auteurs: O. O. Sy;Z. S. Haddad;G. L. Stephens;S. Hristova-Veleva;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2898 - 2912
Editeur: IEEE
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» Design and Applications of Approximate Circuits by Gate-Level Pruning
Résumé:
Energy-efficiency is a critical concern for many systems, ranging from Internet of things objects and mobile devices to high-performance computers. Moreover, after 40 years of prosperity, Moore’s law is starting to show its economic and technical limits. Noticing that many circuits are over-engineered and that many applications are error-resilient or require less precision than offered by the existing hardware, approximate computing has emerged as a potential solution to pursue improvements of digital circuits. In this regard, a technique to systematically tradeoff accuracy in exchange for area, power, and delay savings in digital circuits is proposed: gate-level pruning (GLP). A CAD tool is build and integrated into a standard digital flow to offer a wide range of cost-accuracy tradeoffs for any conventional design. The methodology is first demonstrated on adders, achieving up to 78% energy-delay-area reduction for 10% mean relative error. It is then detailed how this methodology can be applied on a more complex system composed of a multitude of arithmetic blocks and memory: the discrete cosine transform (DCT), which is a key building block for image and video processing applications. Even though arithmetic circuits represent less than 4% of the entire DCT area, it is shown that the GLP technique can lead to 21% energy-delay-area savings over the entire system for a reasonable image quality loss of 24 dB. This significant saving is achieved thanks to the pruned arithmetic circuits, which sets some nodes at constant values, enabling the synthesis tool to further simplify the circuit and memory.
Auteurs: Jeremy Schlachter;Vincent Camus;Krishna V. Palem;Christian Enz;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1694 - 1702
Editeur: IEEE
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» Design and Characterization of a Gradient-Transparent RF Copper Shield for PET Detector Modules in Hybrid MR-PET Imaging
Résumé:
This paper focuses on the design and the characterization of a frequency-selective shield for positron emission tomography (PET) detector modules of hybrid magnetic resonance-PET scanners, where the shielding of the PET cassettes is located close to the observed object. The proposed shielding configuration is designed and optimized to guarantee a high shielding effectiveness (SE) of up to 60 dB for ${B} _{1}$ -fields at the Larmor frequency of 64 MHz, thus preventing interactions between the radio-frequency (RF) coil and PET electronics. On the other hand, the shield is transparent to the gradient fields with the consequence that eddy-current artifacts in the acquired EPI images are significantly reduced with respect to the standard solid-shield configuration. The frequency-selective behavior of the shield is characterized and validated via simulation studies with CST MICROWAVE STUDIO in the megahertz and kilohertz range. Bench measurements with an RF coil built in-house demonstrated the high SE at the Larmor frequency. Moreover, measurements on a 4-T human scanner confirmed the abolishment of eddy current artifact and also provided an understanding of where the eddy currents occur with respect to the sequence parameters. Simulations and measurements for the proposed shielding concept were compared with a solid copper shielding configuration.
Auteurs: Arne Berneking;Riccardo Trinchero;YongHyun Ha;Felix Finster;Piergiorgio Cerello;Christoph Lerche;Nadim Jon Shah;
Apparue dans: IEEE Transactions on Nuclear Science
Date publication: 05.-2017, volume: 64, issue:5, pages: 1118 - 1127
Editeur: IEEE
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» Design and Characterization of a Rotating Brushless Outer Pole PM Exciter for a Synchronous Generator
Résumé:
Generally, PM machines are used as PMG pre-exciters in 3-stage brushless excitations systems. This paper presents the design, characterization, and prototyping of a rotating brushless PM exciter used in a proposed 2-stage excitation system for a synchronous generator. The proposed design reduces the number of components compared with conventional systems. A comparison with the state-of-the-art conventional excitation systems is given. The design of a fast-response, or high initial response, brushless exciter requires active rectification on the rotating frame, replacing the noncontrollable diode bridge. The objective was to construct an exciter with the capability of a 50 A output field current, as well as a high value of the available ceiling voltage and ceiling current. The final exciter was constructed to be fitted into an in-house synchronous generator test setup. A finite element model of the exciter was validated with experimental measurements. The exciter prototype is also compared with an alternative armature design with nonoverlapping single-layer concentrated windings, but with the same main dimensions. The paper includes a general design procedure suitable for optimization of PM brushless exciters that fulfill the requirements of their synchronous generators and the grid.
Auteurs: Jonas Kristiansen Nøland;Fredrik Evestedt;J. José Pérez-Loya;Johan Abrahamsson;Urban Lundin;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2016 - 2027
Editeur: IEEE
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» Design and Experimental Evaluation of a Time-Interleaved ADC Calibration Algorithm for Application in High-Speed Communication Systems
Résumé:
In this work we investigate a new background calibration technique to compensate sampling phase errors in time-interleaved analog-to-digital-converters (TI-ADCs). Timing mismatches in TI-ADC degrade significantly the performance of ultra-high-speed digital transceivers. Unlike previous proposals, the calibration technique used here optimizes a metric directly related to the performance of the communication system. Estimation of gradient of the mean-squared-error (MSE) at the slicer with respect to the sampling phases of each interleave, are computed to minimize the time errors of the TI-ADC by controlling programmable analog time delay-cells. Since ( ${i}$ ) dedicated digital signal processing (DSP) such as cross-correlations or digital filtering of the received samples are not required, and (ii) metrics such as MSE are available in most commercial transceivers, the implementation is reduced to a low speed state-machine. The technique is verified experimentally by using a programmable logic-based platform with a 2 GS/s 6-bit TI-ADC. The latter has been fabricated in $0.13mu text {m}$ CMOS process, and it provides flexible sampling phase control capabilities. Experimental results show that the signal-to-noise ratio penalty of a digital BPSK receiver caused by sampling time errors in TI-ADC, can be reduced from 1 dB to less than 0.1 dB at a bit-error-rate of $mathrm {10^{-6}}$ .
Auteurs: Benjamín T. Reyes;Raúl M. Sanchez;Ariel L. Pola;Mario R. Hueda;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1019 - 1030
Editeur: IEEE
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» Design and Performance of a Wideband Ka-Band 5-b MMIC Phase Shifter
Résumé:
In this letter, the design and performance of a Ka-band 5-b monolithic microwave integrated circuit phase shifter is presented. In the 180° phase bit, a developed switched-path-type topology is employed in order to extend the bandwidth and achieve good phase shifting characteristics. The fabricated phase shifter demonstrates an rms phase error of less than 4.7° and an rms amplitude error of less than 0.6 dB over the frequency band from 31 to 40 GHz. The input and output return loss is measured to be better than 9 dB, and the chip size is 2.55 mm $times1.3$ mm.
Auteurs: Qin Zheng;Zhiyu Wang;Kangrui Wang;Gang Wang;Hui Xu;Liping Wang;Wei Chen;Min Zhou;Zhengliang Huang;Faxin Yu;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 482 - 484
Editeur: IEEE
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» Design Criterion for SiC BJTs to Avoid ON-Characteristics Degradation Due to Base Spreading Resistance
Résumé:
It is empirically known that the ON-resistance (voltage) of the SiC bipolar junction transistors (BJTs) with a thin-base layer is prone to be larger than the resistance of a voltage-blocking collector layer. In this paper, we explain the mechanism of this degradation of ON-characteristics by focusing on a high base spreading resistance and a parasitic diode existing below the base contact. An equivalent circuit model of the SiC BJT was proposed, and SPICE simulation was performed.In addition, TCAD simulation confirmed the validity of the model well. Based on the model, a design criterion to avoid the unwanted increase of the ON-resistance is proposed.
Auteurs: Satoshi Asada;Tsunenobu Kimoto;Jun Suda;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2086 - 2091
Editeur: IEEE
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» Design framework for optimizing maintenance efficiency in ofdma-pons supporting wireline–wireless convergence
Résumé:
Recently, a novel passive optical network (PON) has been proposed based on orthogonal frequency division multiple access (OFDMA) technology. The OFDMAPON provides the opportunity for the convergence of wireline and wireless services. Moreover, virtual subcarrier scheduling can be achieved by virtualization, thus hiding the difference of heterogeneous multiplexing methods in the OFDMA-PON supporting wireline and wireless services. In the multi-segment OFDMA-PON topology, each segment is connected to a distribution fiber. If all distribution fibers are under maintenance simultaneously, the service continuity will be disrupted, thus necessitating an appropriate virtual subcarrier scheduling scheme. In this paper, by migrating the traffic of virtual subcarriers during each maintenance batch, only a partial set of distribution fibers is maintained, leaving the remaining ones to fully support the operation. We formulate the problem aiming to minimize the number of maintenance batches while guaranteeing an acceptable scheduling period. The NPhard problem, feasibility conditions, and lower bound are analyzed. We also design a novel virtual subcarrier scheduling algorithm to solve the problem. Simulations show that the heuristic solution well matches the lower bound with a high convergence ratio of 93%. The optimal scheduling period is also determined.
Auteurs: Xiaoxue Gong;Lei Guo;Xin Fan;
Apparue dans: IEEE/OSA Journal of Optical Communications and Networking
Date publication: 05.-2017, volume: 9, issue:5, pages: 423 - 432
Editeur: IEEE
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» Design of a CMOS Chlorophyll Concentration Detector Based on Organic Chlorophyll Battery for Measuring Vegetable Chlorophyll Concentration
Résumé:
In this paper, a CMOS chlorophyll concentration detector based on organic chlorophyll battery for measuring vegetable chlorophyll concentration is newly proposed. The organic chlorophyll battery and analog processing circuits are compactly and robustly cooperated. Comparing with previous works, the proposed chlorophyll concentration detector can be possibly easy and low-cost realized by users. All the functions and performance of the proposed chlorophyll concentration detector for measuring vegetable chlorophyll concentration are successfully tested and proven through measurements. The measured chlorophyll concentration of spinach ranges from 25 to $475~mu $ mol/ $text{m}^{2}$ , and the corresponding output frequency range is 599.2 kHz–1.174 MHz. The proposed chlorophyll concentration detector is suitable for devices measuring vegetable chlorophyll concentration.
Auteurs: Cheng-Ta Chiang;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1725 - 1730
Editeur: IEEE
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» Design of a Coaxially Magnetic-Geared Linear Actuator for Electric Power Steering System Applications
Résumé:
This paper will present the designs and feasibility assessments of a linear electromagnetic actuator that can directly provide the electric power steering (EPS) forces for an economy sized vehicle. Within the physical and operational constraints, a tubular device being composed by a linear permanent magnet motor and a magnetic gears set will be systematically designed to form the coaxially magnetic-geared linear actuator. Determinations of the optimized geometrical compositions of the motor and the gears set based on the fluxes and thrust forces will be assessed in detail. For practical considerations, the dynamic performances of the proposed EPS system and the corresponding radii of turning circles will also be evaluated at various driving speeds. It is thus confirmed that the adoptions of such electromagnetic systems for those common EPS systems are technically feasible.
Auteurs: Cheng-Tsung Liu;Chang-Chou Hwang;Yu-Wen Chiu;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2401 - 2408
Editeur: IEEE
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» Design of a Combined Function Magnet With Individually Adjustable Functions
Résumé:
Design of combined function magnets for accelerators is often limited to minor modifications of the existing components, maintaining the high quality of the main harmonic field component, but restricting the range of operation. We investigate the possibility to achieve a wide range of both steering magnetic flux density and focusing field gradients, by utilizing two individually powered magnet parts. A general design methodology is presented, enabling fully customized design and optimization of magnets for different applications. The design procedure is illustrated via a detailed design of a magnet proposed for application in the stripping extraction system of a multipurpose cyclotron.
Auteurs: Andjelija Ž. Ilić;Saša T. Ćirković;Milan M. Ilić;Jasna L. Ristić-Djurović;
Apparue dans: IEEE Transactions on Nuclear Science
Date publication: 05.-2017, volume: 64, issue:5, pages: 1109 - 1117
Editeur: IEEE
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» Design of a Near-Field Nonperiodic Zero Phase Shift-Line Loop Antenna With a Full Dispersion Characterization
Résumé:
The tradeoff between the magnetic field distribution, the magnetic field intensity, and the interrogation zone size is one of the most challenging issues in designing a zero phase shift-line (ZPSL) loop antenna for near-field ultrahigh-frequency radio frequency identification (RFID) applications. In this communication, the dispersion characteristics, including phase and attenuation constants, of the ZPSL in a loop configuration are thoroughly analyzed, such that the important design tradeoff can be fully quantified. Based on the dispersion characteristics, a nonperiodic ZPSL loop antenna with nonuniformly arranged unit cells is proposed. Compared with the periodic configurations, the proposed nonperiodic ZPSL loop antenna shows an improved magnetic field distribution with an enhanced magnetic field intensity.
Auteurs: Yunjia Zeng;Zhi Ning Chen;Xianming Qing;Jian-Ming Jin;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2666 - 2670
Editeur: IEEE
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» Design of a Novel Wideband and Dual-Polarized MagnetoElectric Dipole Antenna
Résumé:
A wideband antenna with ±45° dual polarization is proposed. The antenna is mainly comprised of four printed trapezoidal metal walls standing on a ground plane that forms a 3-D open square aperture cavity structure with tapered cut on the four wall edges. The metal walls are fed by two orthogonally positioned (±45°) feeding networks, forming two pairs of dipole arms. Because of the excited magnetic-electric resonances, wide bandwidth can be achieved. The proposed antenna is fabricated, and the measured results show that it has an impedance bandwidth of 56% (1.62–2.87 GHz) for VSWR < 1.5. In addition, isolation of larger than 30 dB is also exhibited across the bandwidth between the two feeding ports. Because the proposed antenna has a hollow inside structure, it is a good candidate for multiband sharing aperture antenna element. Furthermore, it has a simplified fabrication process and is suitable for outdoor base station antennas that require VSWR < 1.5.
Auteurs: Shi-Gang Zhou;Zhao-Hang Peng;Guan-Long Huang;Chow-Yen-Desmond Sim;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2645 - 2649
Editeur: IEEE
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» Design of a Wideband Antenna With Stable Omnidirectional Radiation Pattern Using the Theory of Characteristic Modes
Résumé:
In this communication, the design procedure of a wideband antenna with omnidirectional radiation pattern is demonstrated based on the theory of characteristic modes. Consisting of a dipole and a loop antenna, the antenna has a very simple structure. A wide impedance bandwidth is obtained because of the simultaneous excitation of the antenna’s first two modes. Meanwhile, due to the fact that these two modes share a similar omnidirectional radiation pattern, a stable radiation pattern is also achieved across the operating frequency band. In order to identify the antenna’s different modes, a characteristic mode analysis of the antenna is carried out first. Then, a feed configuration is specifically designed to excite the desired modes. To validate the antenna design, a prototype was fabricated and tested. Measured results agree well with the simulated ones. Measurement shows that a wide impedance bandwidth of 44.2% with $vert {text{S}_{11}}vert < -10$ dB (1.85–2.9 GHz) and stable radiation patterns at both E-plane and H-plane were achieved over the operating frequency band.
Auteurs: Dingliang Wen;Yang Hao;Hanyang Wang;Hai Zhou;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2671 - 2676
Editeur: IEEE
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» Design of Efficient BCD Adders in Quantum-Dot Cellular Automata
Résumé:
Among the emerging technologies recently proposed as alternatives to the classic CMOS, quantum-dot cellular automata (QCA) is one of the most promising solutions to design ultralow-power and very high speed digital circuits. Efficient QCA-based implementations have been demonstrated for several binary and decimal arithmetic circuits, but significant improvements are still possible if the logic gates inherently available within the QCA technology are smartly exploited. This brief proposes a new approach to design QCA-based BCD adders. Exploiting innovative logic formulations and purpose-designed QCA modules, computational speed significantly higher than existing counterparts is achieved without sacrificing either the occupied area or the cell count.
Auteurs: G. Cocorullo;P. Corsonello;F. Frustaci;S. Perri;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 575 - 579
Editeur: IEEE
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» Design of Efficient Multiplierless Modified Cosine-Based Comb Decimation Filters: Analysis and Implementation
Résumé:
This paper presents a computationally efficient design of modified cosine-based decimation filters. One of the main contributions of this paper is the proposal of a multiplierless finite impulse response low-order linear-phase filter to increase spurious signal rejection in the so-called folding bands. The resulting filters feature reduced computational complexity compared with other recent proposals in the literature, as well as higher folding-band attenuation than traditional comb filters. The frequency behavior of the proposed class of decimation filters is compared with generalized comb filters as well as other proposals in the recent literature. Moreover, this paper addresses field-programmable gate array implementation of the proposed filters in a variety of structures, including both nonrecursive and recursive architectures, and it evaluates and compares the performance of these architectures in terms of area and power consumption. A critical comparison is provided with the goal of highlighting key design issues and computational efficient implementations for the interested reader.
Auteurs: Gordana Jovanovic Dolecek;Jose Ricardo Garcia Baez;Massimiliano Laddomada;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1051 - 1063
Editeur: IEEE
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» Design of Pedestrian Target Selection With Funnel Map for Pedestrian AEB System
Résumé:
Recently, numerous vehicles have been installed with an autonomous emergency braking (AEB) system for protecting pedestrians. This system helps in avoiding or reducing accidents by alerting the driver and controlling the automatic brake actuator before an accident. Moreover, the European New Car Assessment Program (NCAP) has stipulated AEB pedestrian systems as a standard requirement since 2016. This paper presents pedestrian target selection using a funnel map for a pedestrian AEB system. The concept of target selection is based on crash probability calculations by comparing the pedestrian's predicted position and the current position to deduce the vehicle speed before an accident occurs. It is necessary to allow early breaking to avoid an accident. To determine the precise warning and brake timing, the warning distance is calculated using the vehicle and sensor fusion information. The pedestrian target selection algorithm is tested using a real vehicle on a test track in three different scenarios for the Euro NCAP using a pedestrian dummy authorized by the Euro NCAP. Upon comparing the results before and after the application of the proposed algorithm, the longitudinal distance is shown to have a maximum margin of 1.5 m, and the vehicle speed has a maximum reduction effect of 24.7 km/h. Test results show that the proposed pedestrian AEB system can avoid or mitigate an accident when the vehicle travels at speeds up to 40 km/h.
Auteurs: Min-Ki Park;Sang-Yeob Lee;Chan-Keun Kwon;Soo-Won Kim;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 3597 - 3609
Editeur: IEEE
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» Design of Power and Area Efficient Approximate Multipliers
Résumé:
Approximate computing can decrease the design complexity with an increase in performance and power efficiency for error resilient applications. This brief deals with a new design approach for approximation of multipliers. The partial products of the multiplier are altered to introduce varying probability terms. Logic complexity of approximation is varied for the accumulation of altered partial products based on their probability. The proposed approximation is utilized in two variants of 16-bit multipliers. Synthesis results reveal that two proposed multipliers achieve power savings of 72% and 38%, respectively, compared to an exact multiplier. They have better precision when compared to existing approximate multipliers. Mean relative error figures are as low as 7.6% and 0.02% for the proposed approximate multipliers, which are better than the previous works. Performance of the proposed multipliers is evaluated with an image processing application, where one of the proposed models achieves the highest peak signal to noise ratio.
Auteurs: Suganthi Venkatachalam;Seok-Bum Ko;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1782 - 1786
Editeur: IEEE
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» Design of Printed Chipless-RFID Tags With QR-Code Appearance Based on Genetic Algorithm
Résumé:
In this paper, the design of the chipless-Radio Frequency Identification (RFID) tags based on genetic algorithm (GA) optimization techniques is introduced. The GA is applied for the first time to create a family of frequency-domain chipless tags with a quick responselike appearance. The resultant tags have an area of 30 mm $times $ 30 mm and consist of a grid of small metallic elements arranged arbitrarily over a $60 times 60$ element array creating a variety of new structures. The frequency signature of the GA-based tags is optimized to fit with a frequency-shift keying-based coding methodology and a capacity of 8 b is achieved. The performance of the resultant tags is experimentally verified. Optimal tag samples are fabricated using silver-ink, low-cost flexible substrates, and by screen printing, which is a mass-compatible production technique. The feasibility of this optimization technique for the design of chipless-RFID tags is corroborated.
Auteurs: Diego Betancourt;Marvin Barahona;Katherina Haase;Georg Schmidt;Arved Hübler;Frank Ellinger;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2190 - 2195
Editeur: IEEE
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» Design of Reduced-Order Positive Linear Functional Observers for Positive Time-Delay Systems
Résumé:
This brief considers a new problem of designing reduced-order positive linear functional observers for positive time-delay systems. The order of the designed functional observers is equal to the dimension of the functional state vector to be estimated. The designed functional observers are always nonnegative at any time and they converge asymptotically to the true functional state vector. Moreover, conditions for the existence of such positive linear functional observers are formulated in terms of linear programming. Numerical examples and simulation results are given to illustrate the effectiveness of the proposed design method.
Auteurs: H. Trinh;D. C. Huong;L. V. Hien;S. Nahavandi;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 555 - 559
Editeur: IEEE
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» Design of SRR-Based Microwave Sensor for Characterization of Magnetodielectric Substrates
Résumé:
A novel split-ring resonator (SRR)-based microwave sensor for accurately determining the real parts of the complex permittivity and the complex permeability of magnetodielectric composites is proposed. The proposed sensor is realized using the microstrip technology, where two SRRs coupled magnetically with the microstrip line are printed on two sides of the line. The sensor is designed using the full-wave electromagnetic solver and its equivalent circuit model is obtained. A numerical model of the proposed sensor is developed for extracting the magnetic and the dielectric properties of the sample under test in terms of change in resonance frequency after loading the device with the test specimen. The proposed methodology is validated by fabricating the sensor on RT/duroid 6006 substrate and testing various standard dielectric and magnetodielectric samples viz. Teflon, Poly vinyl chloride, Plexiglas, Polyethylene, Carbonyl iron, Ni0.6Co0.4Fe2O4, and Cobalt (30%)/Polystyrene composite in S-band. The measured relative permeability and the relative permittivity of the test specimens are found to be in close agreement with their values available in literature with maximum error of less than 8%.
Auteurs: Muhammed Shafi K T;M. Arif Hussain Ansari;Abhishek Kumar Jha;M. Jaleel Akhtar;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 524 - 526
Editeur: IEEE
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» Design of Surface Acoustic Wave Parafoil Riser Tension Sensor
Résumé:
An increasing demand for the online tension measurement in developing parafoil has arisen. In this paper, a new design for surface acoustic wave (SAW) tension sensor, which can be used to test the parafoil riser tension wirelessly and passively, is discussed. An SAW resonator is used for sensing tension by determining the frequency of the resonant reflection device. In accordance with the test requirements, a nondestructive side-loading tension testing structure is created by which stress analysis and optimization can be operated in ANSYS. To understand the relationship between size and frequency of the antenna in the sensor, a new antenna design called microstrip antenna is proposed following the high frequency structure simulator analysis. The proposed design shows good linearity and sensitivity between the SAW frequency and the riser tension through the actual experiment, which meets the stringent requirement for the shape of the sensor. Thus, the sensor can obtain tension measurement during the operation of the parafoil riser.
Auteurs: Min Zhao;Hang Zhang;Ruoyun Zhang;Min Yao;Minyu Ma;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3022 - 3029
Editeur: IEEE
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» Design of Synchronous Reluctance Motor Utilizing Dual-Phase Material for Traction Applications
Résumé:
While interior permanent magnet (IPM) machines have been considered the state-of-the art for traction motors, synchronous reluctance (SynRel) motors with advanced materials can provide a competitive alternative. IPM machines typically utilize neodymium iron boron permanent magnets, which pose an issue in terms of price, sustainability, demagnetization at higher operating temperatures, and uncontrolled generation. On the other hand, SynRel machines do not contain any magnets and are free from these issues. However, the absence of magnets as well the presence of bridges and center post limit the flux-weakening capability of a SynRel machine and limit the achievable constant power speed ratio for a given power converter rating. In this paper, a new material referred to as the dual-phase magnetic material will be evaluated for SynRel designs. This material allows for nonmagnetic regions to be selectively introduced in the bridge and post regions, thereby eliminating one of the key limitations of the SynRel designs in terms of torque density and flux weakening. This paper will focus on advanced SynRel designs utilizing dual-phase material targeting traction applications. The paper will provide a detailed comparison between a dual-phase SynRel design, a conventional SynRel design, and a spoke PM design with rare-earth-free magnets. It will highlight the key tradeoffs in terms of power density, efficiency, and flux-weakening capability.
Auteurs: Patel Bhageerath Reddy;Ayman M. El-Refaie;Steven Galioto;James P. Alexander;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 1948 - 1957
Editeur: IEEE
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» Design of Thin Cladding BIF Using Cutoff Wavelength Shortening Effect
Résumé:
We experimentally investigate the cutoff wavelength shortening effect that occurs when the cladding diameter is reduced. The influence of coating thickness, and thus, cladding diameter, on the transmission loss is also discussed. We derive an empirical model of cutoff wavelength and transmission loss as a function of the cladding diameter and coating thickness. The empirical model reveals that a further reduction in the cladding diameter of step index type bending-loss insensitive fiber (BIF) is possible. The validity of the proposed BIF design is confirmed using a 70-μm cladding diameter BIF and jumper cords. This BIF enables us to construct optical fiber networks with higher reliability.
Auteurs: Yukihiro Goto;Kazuhide Nakajima;Chisato Fukai;Kotaro Saito;Toshio Kurashima;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1945 - 1951
Editeur: IEEE
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» Design Space–Time Trellis-Coded Intercarrier Interference Parallel Cancelation Architectures for OFDM Systems
Résumé:
Space–time (ST) coding combined with orthogonal frequency-division multiplexing (OFDM) is a robust transmission system. However, ST-OFDM system performance may degrade because of the intercarrier interference (ICI) in frequency-selective fading channels. To mitigate the ICI, a parallel cancelation (PC) algorithm is employed and combined with a 2 $times$ 1 ST code to form an STPC-OFDM system. Further developing the idea of the STPC-OFDM system, we design a modified ST trellis-coded (STTC)-ST-OFDM system and the novel STTC-STPC-OFDM architecture and algorithms to mitigate ICI without expending power or bandwidth or significant complexity. Since this new system integrates ICI PC with channel coding gain and diversity gain, its bit-error-rate performance is better compared with the STPC-OFDM system with a lower error floor in frequency-selective mobile fading channels. Moreover, the Walsh–Hadamard (WH) transformation is further applied to the STTC-STPC-OFDM system to form a novel STTC-WH-STPC-OFDM architecture and improve the overall system performance significantly with the same data rate, same power, and same complexity as that of STTC-STPC-OFDM systems.
Auteurs: Hen-Geul Yeh;Samet Yıldız;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 530 - 534
Editeur: IEEE
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» Design Structure Matrix Modeling of a Supply Chain Management System Using Biperspective Group Decision
Résumé:
This paper introduces the procedure and results of the dependence modeling for a complex supply chain management (SCM) system using the design structure matrix (DSM). The elements of the DSM are determined by the functional analysis of the overall SCM system. Population of the matrix results from utilizing the biperspective group decision method, which evaluates the degree of dependence between the influencing and the dependent components. More specifically, this is accomplished by separately eliciting the opinions of the two parties and systematically obtaining the converged assessment. A case study for dependence modeling of an SCM system of a leading aircraft manufacturer is presented. From the obtained model, we can better understand the cross-functional interactions among the components of an SCM system and corresponding behaviors. Thus, this paper analyzes the gaps between the degrees of dependence perceived by the two parties and provides some discussions on how the analysis results can be used to improve the operation of the system.
Auteurs: Samuel Son;Junhong Kim;Jaemyung Ahn;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 05.-2017, volume: 64, issue:2, pages: 220 - 233
Editeur: IEEE
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» Design-Space Exploration and Optimization of an Energy-Efficient and Reliable 3-D Small-World Network-on-Chip
Résumé:
A 3-D network-on-chip (NoC) enables the design of high performance and low power many-core chips. Existing 3-D NoCs are inadequate for meeting the ever-increasing performance requirements of many-core processors since they are simple extensions of regular 2-D architectures and they do not fully exploit the advantages provided by 3-D integration. Moreover, the anticipated performance gain of a 3-D NoC-enabled many-core chip may be compromised due to the potential failures of through-silicon-vias that are predominantly used as vertical interconnects in a 3-D IC. To address these problems, we propose a machine-learning-inspired predictive design methodology for energy-efficient and reliable many-core architectures enabled by 3-D integration. We demonstrate that a small-world network-based 3-D NoC (3-D SWNoC) performs significantly better than its 3-D MESH-based counterparts. On average, the 3-D SWNoC shows 35% energy-delay-product improvement over 3-D MESH for the PARSEC and SPLASH2 benchmarks considered in this paper. To improve the reliability of 3-D NoC, we propose a computationally efficient spare-vertical link (sVL) allocation algorithm based on a state-space search formulation. Our results show that the proposed sVL allocation algorithm can significantly improve the reliability as well as the lifetime of 3-D SWNoC.
Auteurs: Sourav Das;Janardhan Rao Doppa;Partha Pratim Pande;Krishnendu Chakrabarty;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 719 - 732
Editeur: IEEE
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» Designing Effective Privacy Notices and Controls
Résumé:
Privacy notice and choice are essential aspects of privacy and data protection regulation worldwide. Yet, today's privacy notices and controls are surprisingly ineffective at informing users or allowing them to express choice. Here, the authors analyze why existing privacy notices fail to inform users and tend to leave them helpless, and discuss principles for designing more effective privacy notices and controls.
Auteurs: Florian Schaub;Rebecca Balebako;Lorrie Faith Cranor;
Apparue dans: IEEE Internet Computing
Date publication: 05.-2017, volume: 21, issue:3, pages: 70 - 77
Editeur: IEEE
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» Detecting a Suddenly Arriving Dynamic Profile of Finite Duration
Résumé:
This paper addresses the detection of a suddenly arriving dynamic profile of a finite duration often called a transient change. In contrast to the traditional abrupt change detection, where the post-change period is assumed to be infinitely long, the detection of a suddenly arriving transient change should be done before it disappears. The detection of transient changes after their disappearance is considered as missed. Hence, the traditional quickest change detection criterion, minimizing the average detection delays provided a prescribed false alarm rate, is compromised. The proposed optimality criterion minimizes the worst case probability of missed detection provided that the worst case probability of false alarm during a certain period is upper bounded. A suboptimal CUSUM-type transient change detection algorithm, based on a subclass of truncated Sequential Probability Ratio Tests, is proposed. The optimization of the proposed algorithm in this subclass leads to a specially designed Finite Moving Average Test. The proposed method is analyzed theoretically and by simulation. A special attention is paid to the case of Gaussian observations with a dynamic profile.
Auteurs: Blaise Kévin Guépié;Lionel Fillatre;Igor Nikiforov;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3039 - 3052
Editeur: IEEE
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» Detecting Cardiovascular Disease from Mammograms With Deep Learning
Résumé:
Coronary artery disease is a major cause of death in women. Breast arterial calcifications (BACs), detected inmammograms, can be useful riskmarkers associated with the disease. We investigate the feasibility of automated and accurate detection ofBACsinmammograms for risk assessment of coronary artery disease. We develop a 12-layer convolutional neural network to discriminate BAC from non-BAC and apply a pixelwise, patch-based procedure for BAC detection. To assess the performance of the system, we conduct a reader study to provide ground-truth information using the consensus of human expert radiologists. We evaluate the performance using a set of 840 full-field digital mammograms from 210 cases, using both free-responsereceiveroperatingcharacteristic (FROC) analysis and calcium mass quantification analysis. The FROC analysis shows that the deep learning approach achieves a level of detection similar to the human experts. The calcium mass quantification analysis shows that the inferred calcium mass is close to the ground truth, with a linear regression between them yielding a coefficient of determination of 96.24%. Taken together, these results suggest that deep learning can be used effectively to develop an automated system for BAC detection inmammograms to help identify and assess patients with cardiovascular risks.
Auteurs: Juan Wang;Huanjun Ding;Fatemeh Azamian Bidgoli;Brian Zhou;Carlos Iribarren;Sabee Molloi;Pierre Baldi;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 05.-2017, volume: 36, issue:5, pages: 1172 - 1181
Editeur: IEEE
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» Detecting Flying Objects Using a Single Moving Camera
Résumé:
We propose an approach for detecting flying objects such as Unmanned Aerial Vehicles (UAVs) and aircrafts when they occupy a small portion of the field of view, possibly moving against complex backgrounds, and are filmed by a camera that itself moves. We argue that solving such a difficult problem requires combining both appearance and motion cues. To this end we propose a regression-based approach for object-centric motion stabilization of image patches that allows us to achieve effective classification on spatio-temporal image cubes and outperform state-of-the-art techniques. As this problem has not yet been extensively studied, no test datasets are publicly available. We therefore built our own, both for UAVs and aircrafts, and will make them publicly available so they can be used to benchmark future flying object detection and collision avoidance algorithms.
Auteurs: Artem Rozantsev;Vincent Lepetit;Pascal Fua;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 05.-2017, volume: 39, issue:5, pages: 879 - 892
Editeur: IEEE
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» Determination of Cell Coverage Area and its Applications in High-Speed Railway Environments
Résumé:
In this paper, a determination method of the cell coverage area for the narrow-strip-shaped cells in high-speed railways (HSRs) is proposed, which is of great importance to HSR dedicated communication network planning. A closed-form expression for the cell coverage area is first derived on the basis of the edge outage probability and the propagation channel parameters, and it is found that the linear coverage in HSRs has a higher percentage of coverage area than the traditional circular coverage of cellular systems. For the convenience of link budget computation, we also present a family of curves related with the percentage of linear coverage. Then, the implementation of the proposed determination of cell coverage area is presented, and it is found that the linear cell of HSRs has a larger maximum communication distance than circular coverage. Furthermore, the impact of frequency on the HSR link budget is investigated, and the results show that a lower frequency band reduces the number of the required base stations. The results can be used in designing and optimizing the wireless coverage and the communication network planning of HSR communications.
Auteurs: Bo Ai;Ruisi He;Guangkai Li;Ke Guan;Danping He;Guowei Shi;Zhangdui Zhong;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 3515 - 3525
Editeur: IEEE
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» Determination of Trace Lead Detection in a Sample Solution by Liquid Three-Phase Microextraction–Anodic Stripping Voltammetry
Résumé:
Herein, the micro extraction and quantification of lead (II) ions were investigated in trace levels on in situ pulse anodic stripping voltammetry (DPASV) and polytetrafluorethylene (PTFE) membrane-based liquid three-phase micro extraction. The voltammetric cell contained the acceptor solution and reference, the counter, and working electrodes. The modified Pt electrode with 3-Trimethoxysilyl-1-propanethiol and gold nanoparticles (Au NPs), respectively, was applied as the working electrode. The voltammetric cell combined with DPASV was utilized in situ during the extraction time. The obtained results showed the effect of different factors on the pre-concentration and micro extraction of lead ions, including the organic solvent, pH of the donor and acceptor phases, concentration of the complexion agent, extraction time, stirring rate, and electrochemical factors; also, the optimal extraction conditions were established. The final stable signal was achieved after 18-min extraction time for analytical applications. The relative standard deviation and the enrichment factor were obtained to be 6.0% ( $n=5$ ) and 18, respectively. The calibration curve was obtained in the range of 0.207–62.1 ppb Pb(II) (analytical equation: $y=$ 3.986 $x+$ 0.381), and the limit of detection was found to be 0.021 ppb with optimum conditions. The lead (II) ions were determined in fish, rice, and wastewater samples.
Auteurs: Alireza Allafchian;Seyede Zohreh Mirahmadi-Zare;Marzieh Gholamian;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2856 - 2862
Editeur: IEEE
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» Determining Junction Temperature of LEDs by the Relative Reflected Intensity of the Incident Exciting Light
Résumé:
Relative reflected intensity of the incident exciting light is proposed to measure the junction temperature of light-emitting diodes (LEDs) under test. Reflectance spectra at a wide junction temperature range are acquired. Multichannel optical fibers greatly increase the collecting efficiency of the reflected light. Lock-in technique is utilized to exclude the interference of the emitting light from LEDs under test and to increase the dynamic range greatly. The results are in good agreement with those directly tested by a microthermocouple. To avoid extra carrier absorption and modulation effect, the incident exciting light should harbor smaller bandgap than that of LEDs under test.
Auteurs: Yao Xiao;Ting-Zhu Wu;Si-Jia Dang;Yu-Lin Gao;Yue Lin;Li-Hong Zhu;Zi-Quan Guo;Yi-Jun Lu;Zhong Chen;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2257 - 2260
Editeur: IEEE
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» Developing Non-Somatotopic Phantom Finger Sensation to Comparable Levels of Somatotopic Sensation through User Training With Electrotactile Stimulation
Résumé:
Cutaneous electrical stimulation can provide tactile feedback for upper-limb amputees through somatotopic feedback (SF) or non-somatotopic feedback (NF). The SF delivers electrotactile stimulus to projection finger maps (PFMs) on the stumps of amputees, which outperforms NF that transfers stimulus to other human intact skin areas in general. However, the SF areas on stumps are very limited and often occupied by electromyography (EMG) sensors in application of myoelectric prosthesis. This work aims at improving NF performance on human upper arms through user training with electrotactile stimulation. The experiments were conducted over seven consecutive days on nine able-bodied subjects and two forearm amputees. The performance measures of NF/SF included the correct identification rates (CIRs), the response time and the NASA-TLX questionnaire. The between-day CIR s on NF sites increased logarithmically with a mean course of 3-day rapid-improving phase and plateaued in the relative-steady phase. The response time and NASA-TLX scores could also rapidly reduce to the comparable levels of the SF areas during the same mean period of 3-day rapid-improving phase, respectively. These results indicated that the performance of NF could be highly improved to the equivalent level as that of SF through 3-day electrotactile training, which we named as “3-day effect”. It provides important insights that intact skin areas without phantom sensations can effectively replace SF sites to transfer tactile feedback after continuous user training, which validates effectiveness of non-invasive interfaces of tactile feedback for upper-limb amputees in practice.
Auteurs: Guohong Chai;Dingguo Zhang;Xiangyang Zhu;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 05.-2017, volume: 25, issue:5, pages: 469 - 480
Editeur: IEEE
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» Development and Repetitive Learning Control of Lower Limb Exoskeleton Driven by Electrohydraulic Actuators
Résumé:
This paper presents a novel development of lower limb exoskeleton, which is named as CASWELL, and its repetitive learning control design for movement assistance. CASWELL has five degrees of freedom per leg, two of which are driven by linear single-rod electrohydraulic actuators. First, the mechanical structure and embedded electronic system are constructed, respectively. Second, by incorporating the systems of rigid body and electrohydraulic actuators, the complete dynamics of CASWELL are analyzed and modeled. Third, under the framework of backstepping design, a repetitive learning control scheme is presented to address the periodic tracking control of lower limbs of exoskeleton, where the learning convergence of the closed-loop system is proved rigorously in a Lyapunov way. Finally, the proposed controller is implemented in the embedded electronic system via a 32-bit microcontroller, and tested on the developed CASWELL. The experimental results are given to demonstrate the performance of the whole exoskeleton system.
Auteurs: Yong Yang;Lei Ma;Deqing Huang;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4169 - 4178
Editeur: IEEE
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» Development and Testing of ZnO Nanorods Based Biosensor on Model Gram-Positive and Gram-Negative Bacteria
Résumé:
Water is a basic human need, but many people do not have access to clean and safe drinking water. Many people die of waterborne bacterial diseases in the world. The presence of bacterial pathogens in water can be detected by using sophisticated and expensive instruments, which take extensive time for measurement. In contrast to those instrumentation, nanostructure-based devices can be used as instant and cheap bacteria sensors. This paper reports the fabrication of a sensor using ZnO nanorods for detection of two bacterial pathogens, namely Escherichia coli, which is a gram-negative bacteria and Streptococcus pneumonia, which is a gram-positive bacteria present in water at different concentrations. The fabrication of the sensor was done by growing ZnO nanorods hydrothermally on a Cu electrode. The sensor was then tested with some known concentrations of bacteria mixed in water. When bacteria mixed water sample is dropped over the sensor, the electrical resistance of the sensor varies proportionally with bacteria concentration. Maximum responses of 96% and 94.375% at room temperature and minimum detection limits of 1.12% and 1.01% were achieved for $9.15times 10^{8}$ cells/mL of E. coli and $1.043times 10^{9}$ cells/mL of S. pneumonia present in water, respectively. The high sensitivity and dynamic repeatability exhibited by these sensors reveal that ZnO nanorods are promising as sensitive and reliable sensors for detecting bacteria present in water.
Auteurs: Rashi Borgohain;Sunandan Baruah;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2649 - 2653
Editeur: IEEE
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» Development of a Parallel Version of PhyML 3.0 Using Shared Memory
Résumé:
This work presents the main steps towards a parallel version of the open source phylogenetic tree reconstruction software PhyML 3.0, which uses the method of maximum likelihood in phylogenetic reconstruction process. The PhyML was parallelized by a shared memory approach (using OpenMP) and at the same time using the version already consolidated in PhyML 3.0, the version passing messages with distributed memory (using MPI), was also constructed a version hybrid (MPI and OpenMP) of PhyML. The tests for the efficiency and speedup were carried out in a cluster of two ways, the first only by analyzing the performance version with OpenMP (DNA and proteins) and the second making a comparative analysis of the performance of three parallel versions (OpenMP, MPI and Hybrid) using DNA data only. The results obtained show speedup of approximately six to 8 cores on 1 server, which allows the use of this code problems that require a lot of time in the serial version, front the need or urgent of the fast processing of data.
Auteurs: Julio Oliveira da Silva;Esbel Tomas Valero Orellana;Martha Ximena Torres Delgado;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 959 - 967
Editeur: IEEE
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» Development of an Acoustic Levitation Linear Transportation System Based on a Ring-Type Structure
Résumé:
A linear acoustic levitation transportation system based on a ring-type vibrator is presented. The system is composed by two 21-kHz Langevin transducers connected to a ring-shaped structure formed by two semicircular sections and two flat plates. In this system, a flexural standing wave is generated along the ring structure, producing an acoustic standing wave between the vibrating ring and a plane reflector located at a distance of approximately a half wavelength from the ring. The acoustic standing wave in air has a series of pressure nodes, where small particles can be levitated and transported. The ring-type transportation system was designed and analyzed by using the finite element method. Additionally, a prototype was built and the acoustic levitation and transport of a small polystyrene particle was demonstrated.
Auteurs: Gilles P. L. Thomas;Marco A. B. Andrade;Julio Cezar Adamowski;Emílio Carlos Nelli Silva;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 839 - 846
Editeur: IEEE
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» Development of epoxy flux for lead-free solder [News from Japan]
Résumé:
Following global trends and international agreements, there is a growing conviction that toxic materials, which are potential health risks, should be eliminated as far as possible from widely used products, even if they lead to superior product characteristics. Thus there is an agreement called RoHS or WEEE within the European Union that bans import or sale of products that contain substances hazardous to human health or the environment. Lead (Pb) is one such hazardous material. Conventional solder used to bond electric wires or conductors contains Pb,and a flux, of which the main component is rosin (derived from turpentine oil), has been for many years combined with conventional solder. However, a new flux more suitable for Pb-free solder must now be developed.
Auteurs: Y. Ohki;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 05.-2017, volume: 33, issue:3, pages: 39 - 41
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Development of INS/GNSS UAV-Borne Vector Gravimetry System
Résumé:
An airborne gravimetry system consisting of an inertial navigation system (INS) and a global navigation satellite system (GNSS) has been proven to perform well in gravity observation. The system is also more cost- or time-effective than satellite missions and terrestrial gravimeters. In this letter, an unmanned aerial vehicle has been developed as a platform to carry the INS/GNSS vector gravimetry system using an unmanned helicopter. In addition to the kinematic mode, the unmanned helicopter can perform the zero velocity update (ZUPT) mode, which is a novel method in the acquisition of gravity. Results show that the accuracies of the horizontal and vertical gravity disturbance from the kinematic mode at crossover points are approximately 6–11 and 4 mGal, respectively, with a 0.5-km resolution. The accuracy of the repeatability in ZUPT mode is evaluated with the accuracies of approximately 2–3 mGal.
Auteurs: Cheng-An Lin;Kai-Wei Chiang;Chung-Yen Kuo;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 759 - 763
Editeur: IEEE
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» Development of Silicon Nanowire-Based NEMS Absolute Pressure Sensor Through Surface Micromachining
Résumé:
This letter reports on a nano-electro-mechanical system (NEMS) pressure sensor with p-doped silicon nanowires (average cross-sectional area ~100 nm2) as piezoresistive sensing elements. Taking advantage of surface micromachining, an absolute pressure-sensing device is developed using front-side isotropic etching. In contrast to the previously reported silicon nanowire (SiNW) pressure sensor processed with bulk micromachining through the backside deep reactive ion etching (DRIE), nonlinearity has been reduced to 0.31% (BFSL). In addition, the performance variations across the wafer have been significantly reduced to 6% in comparison with a 33% sensitivity fluctuation across the 8-inch wafer reported in our early work fabricated by a DRIE process. After front-side vacuum sealing, temperature-induced performance degradation has also been minimized. Moreover, the dramatic geometry downsizing (device footprint $sim 385~mu text{m}^{mathrm {mathbf {2}}}$ ) validates the scalability of the SiNW-based NEMS sensor. With excellent uniformity, the SiNW-based sensor can be commercially manufactured on an 8-inch wafer at lower cost with high yield.
Auteurs: Songsong Zhang;Liang Lou;Yuandong Alex Gu;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 653 - 656
Editeur: IEEE
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» Diagnostic of Insulators of Conventional Grid Through LabVIEW Analysis of FFT Signal Generated from Ultrasound Detector
Résumé:
This article is intended to present an evaluation on the automation capability in the analysis of insulators of conventional grid by processing the signals generated by ultrasound detectors. The insulators analyzed were removed from the electrical system in various conditions, as well as new insulators. The methodology adopted was a practical analysis of qualitative and quantitative way. The audible noise generated by the output of ultrasound equipment is connected to a personal computer to obtain the FFT signal through LabVIEW software. The characteristic of the FFT signal is used to classify inspected components online, allowing for quick and precise procedure, as shown in the results obtained in this study.
Auteurs: Stefano Frizzo Stefenon;Joaquim Rodrigo de Oliveira;Antonio Sergio Coelho;Luiz Henrique Meyer;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 884 - 889
Editeur: IEEE
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» Diamond Tiling: Tiling Techniques to Maximize Parallelism for Stencil Computations
Résumé:
Most stencil computations allow tile-wise concurrent start, i.e., there always exists a face of the iteration space and a set of tiling directions such that all tiles along that face can be started concurrently. This provides load balance and maximizes parallelism. However, existing automatic tiling frameworks often choose hyperplanes that lead to pipelined start-up and load imbalance. We address this issue with a new tiling technique, called diamond tiling, that ensures concurrent start-up as well as perfect load-balance whenever possible. We first provide necessary and sufficient conditions for a set of tiling hyperplanes to allow concurrent start for programs with affine data accesses. We then provide an approach to automatically find such hyperplanes. Experimental evaluation on a 12-core Intel Westmere shows that diamond tiled code is able to outperform a tuned domain-specific stencil code generator by 10 to 40 percent, and previous compiler techniques by a factor of 1.3 \times to 10.1 \times .
Auteurs: Uday Bondhugula;Vinayaka Bandishti;Irshad Pananilath;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1285 - 1298
Editeur: IEEE
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» Differential 3D Scanning
Résumé:
During the creative process, designers use various techniques and strategies to move from the abstract to the concrete, utilizing different physical and virtual means to represent form. The changes between virtual and physical models are not always fluent, however. Differential 3D scanning can detect the differences between a scanned model (point cloud) and a reference model (polygon mesh or CAD model) and then reflect those changes in the reference model. This can save designers time by reconstructing only the small changed regions rather than the entire object.
Auteurs: Ammar Hattab;Ian Gonsher;Daniel Moreno;Gabriel Taubin;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 43 - 51
Editeur: IEEE
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» Differential Evolution Based on Self-Adaptive Fitness Function for Automated Test Case Generation
Résumé:
Testing is one of the most important parts of the software process, which aims at detecting software faults/bugs and thus guarantees the quality of the final product. Its expense is nearly half of the total cost of software development [7], [9]. Most of the current approaches to software testing are manual, but it has been recently suggested [1] that automated testing should be done to save human resources and budget, as well as to produce high-quality software.
Auteurs: Han Huang;Fangqing Liu;Xiaoyan Zhuo;Zhifeng Hao;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 05.-2017, volume: 12, issue:2, pages: 46 - 55
Editeur: IEEE
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» Digit-Level Serial-In Parallel-Out Multiplier Using Redundant Representation for a Class of Finite Fields
Résumé:
Two digit-level finite field multipliers in $mathbb {F}_{2^{m}}$ using redundant representation are presented. Embedding $mathbb {F}_{2^{m}}$ in cyclotomic field $mathbb {F}_{2}^{(n)}$ causes a certain amount of redundancy and consequently performing field multiplication using redundant representation would require more hardware resources. Based on a specific feature of redundant representation in a class of finite fields, two new multiplication algorithms along with their pertaining architectures are proposed to alleviate this problem. Considering area-delay product as a measure of evaluation, it has been shown that both the proposed architectures considerably outperform existing digit-level multipliers using the same basis. It is also shown that for a subset of the fields, the proposed multipliers are of higher performance in terms of area-delay complexities among several recently proposed optimal normal basis multipliers. The main characteristics of the postplace&route application specific integrated circuit implementation of the proposed multipliers for three practical digit sizes are also reported.
Auteurs: Parham Hosseinzadeh Namin;Roberto Muscedere;Majid Ahmadi;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1632 - 1643
Editeur: IEEE
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» Digitally Assisted Analog Interference Cancellation for In-Band Full-Duplex Radios
Résumé:
In this letter, a digitally assisted analog interference cancellation architecture is proposed for the prevailing full-duplex radios, which simultaneously transmit and receive signals on the same carrier frequency. An auxiliary transmit chain is deployed to generate a canceling signal and subtract from the self-interference (SI) signal at the receiver front end to prevent saturating the analog-to-digital converter. To ensure the canceling signal a close approximation of the SI signal, an observation chain is used to extract the transmitter response. Correspondingly, a two-step modeling process is inserted to the auxiliary transmit chain to recover both the nonlinear behavior and the multi-path channel between the transmit and receive chains. Experimental results have validated the superior performance of this architecture, particularly for transmitters of high output power and strong nonlinear distortions.
Auteurs: Ying Liu;Xin Quan;Wensheng Pan;Youxi Tang;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1079 - 1082
Editeur: IEEE
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» Dimensionality Reduction and Classification of Hyperspectral Images Using Ensemble Discriminative Local Metric Learning
Résumé:
The high-dimensional data space of hyperspectral images (HSIs) often result in ill-conditioned formulations, which finally leads to many of the high-dimensional feature spaces being empty and the useful data existing primarily in a subspace. To avoid these problems, we use distance metric learning for dimensionality reduction. The goal of distance metric learning is to incorporate abundant discriminative information by reducing the dimensionality of the data. Considering that global metric learning is not appropriate for all training samples, this paper proposes an ensemble discriminative local metric learning (EDLML) algorithm for HSI analysis. The EDLML algorithm learns robust local metrics from both the training samples and the relative neighborhood of them and considers the different local discriminative distance metrics by dealing with the data region by region. It aims to learn a subspace to keep all the samples in the same class are as near as possible, while those from different classes are separated. The learned local metrics are then used to build an ensemble metric. Experiments on a number of different hyperspectral data sets confirm the effectiveness of the proposed EDLML algorithm compared with that of the other dimension reduction methods.
Auteurs: Yanni Dong;Bo Du;Liangpei Zhang;Lefei Zhang;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2509 - 2524
Editeur: IEEE
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» Direct Estimation of Land Surface Albedo From Simultaneous MISR Data
Résumé:
The availability of multiangular information from the NASA Multi-angle Imaging SpectroRadiometer (MISR) instrument provides an excellent opportunity for the characterization of surface anisotropy, which can be used for improving surface albedo estimation. However, the MISR data have been reported with large uncertainties and data gaps due to inaccurate aerosol estimation and/or cloud masking limiting its otherwise broader applications. To mitigate these issues, two approaches were proposed to estimate land surface albedo directly from surface reflectance (LSA_sfc) and Top-of-Atmosphere reflectance (LSA_toa), respectively. As a further development of the traditional albedo algorithms, this is the first attempt to simultaneously utilize multispectral and multiangular information in surface albedo estimation without any prior constraining information. Validations at AmeriFlux sites show that the proposed algorithms can achieve accuracies similar to that of the MISR product with respective bias and RMSE of 0.004 and 0.032 for LSA_sfc and 0.005 and 0.032 for LSA_toa algorithms. We found that the LSA_toa algorithm can significantly reduce data gaps and provide accurate surface albedo retrievals with two to three times more valid data than the current MISR product. In addition, these approaches can be easily applied to other optical sensors to produce accurate and gap-free clear-sky surface albedo estimations. The results of this paper also highlight the importance of having two to three simultaneous observations with sufficient angular sampling, which can improve albedo accuracy and reduce data gaps.
Auteurs: Tao He;Shunlin Liang;Dongdong Wang;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2605 - 2617
Editeur: IEEE
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» Direct Torque Control Scheme for DC Voltage Regulation of the Standalone DFIG-DC System
Résumé:
This paper deals with a standalone doubly fed induction generator-direct current (DFIG-dc) system, where stator and rotor are connected to an isolated dc load, via diode rectifier and voltage-source inverter, respectively. A direct torque control scheme is proposed for dc voltage regulation, where the dc voltage is regulated by a torque controller, while stator frequency is maintained at a nearly rated frequency, by achieving constant dc voltage to rotor flux ratio. An innovative switching strategy is developed to incorporate the phase sequence change in rotor current from subsynchronous speed to supersynchronous speed. Variable switching due to a hysteresis controller provides a reduction in the harmonic content of stator current. This control is simple in implementation, and less parameter dependent. There is no requirement of exact position sensing, while the speed measurement is sufficient, which also reduces the cost and maintenance of an accurate position sensor. Sensing of stator voltage and current is not required in this scheme, and control is done with a minimum number of sensors. As the number of turns on the stator is higher than the rotor, to have common dc link and to exploit rated stator MMF, roles of stator and rotor are interchanged. Performance of the control scheme is verified experimentally on a 4 kW DFIG, and results are reported.
Auteurs: Akhila Gundavarapu;Himanshu Misra;Amit Kumar Jain;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3502 - 3512
Editeur: IEEE
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» Discrete Adjoint Sensitivity Analysis of Hybrid Dynamical Systems With Switching
Résumé:
Sensitivity analysis is an important tool for describing power system dynamic behavior in response to parameter variations. It is a central component in preventive and corrective control applications. The existing approaches for sensitivity calculations, namely, finite-difference and forward sensitivity analysis, require a computational effort that increases linearly with the number of sensitivity parameters. In this paper, we investigate, implement, and test a discrete adjoint sensitivity approach whose computational effort is effectively independent of the number of sensitivity parameters. The proposed approach is highly efficient for calculating sensitivities of larger systems and is consistent, within machine precision, with the function whose sensitivity we are seeking. This is an essential feature for use in optimization applications. Moreover, our approach includes a consistent treatment of systems with switching, such as dc exciters, by deriving and implementing the adjoint jump conditions that arise from state-dependent and time-dependent switchings. The accuracy and the computational efficiency of the proposed approach are demonstrated in comparison with the forward sensitivity analysis approach. This paper focuses primarily on the power system dynamics, but the approach is general and can be applied to hybrid dynamical systems in a broader range of fields.
Auteurs: Hong Zhang;Shrirang Abhyankar;Emil Constantinescu;Mihai Anitescu;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1247 - 1259
Editeur: IEEE
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» Discrete-Phase Constant Envelope Precoding for Massive MIMO Systems
Résumé:
We consider downlink of a multiuser massive multiple-input multiple-output (MIMO) system and focus on reducing the hardware costs by using a single common power amplifier and separate phase shifters (PSs) for antenna front-ends. In the previous literature, the use of analog PSs in this setup has been considered. Here, we study the use of practical digital PSs, which only support a limited set of discrete phases. Considering the sum of interference powers as a metric, we formulate the corresponding nonlinear discrete optimization problem and solve for the phases to be used during transmission. We devise a low-complexity algorithm, which employs a trellis structure providing suboptimal, but efficient and effective solutions. We demonstrate via examples that the proposed solutions have comparable performance to conventional analog PS-based algorithms. Furthermore, we prove that by utilizing discrete-phase constant envelope precoding, the interference can be made arbitrarily small by increasing the number of antennas. Therefore, the asymptotic gains promised by massive MIMO systems are preserved. We also obtain closed-form expressions for the rate loss due to errors in the phase and amplitude of the PSs, for both low and high SNR regimes.
Auteurs: Mohammad Kazemi;Hassan Aghaeinia;Tolga M. Duman;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 2011 - 2021
Editeur: IEEE
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» Discriminative Reverse Sparse Tracking via Weighted Multitask Learning
Résumé:
Multitask learning has shown great potentiality for visual tracking under a particle filter framework. However, the recent multitask trackers, which exploit the similarity between all candidates by imposing group sparsity on the candidate representations, have a limitation in robustness due to the diverse sampling of candidates. To deal with this issue, we propose a discriminative reverse sparse tracker via weighted multitask learning. Our positive and negative templates are retained from the target observations and the background, respectively. Here, the templates are reversely represented via the candidates, and the representation of each positive template is viewed as a single task. Compared with existing multitask trackers, the proposed algorithm has the following advantages. First, we regularize the target representations with the $ell _{2,1}$ -norm to exploit the similarity shared by the positive templates, which is reasonable because of the target appearance consistency in the tracking process. Second, the valuable prior relationship between the candidates and the templates is introduced into the representation model by a weighted multitask learning scheme. Third, both target information and background information are integrated to generate discriminative scores for enhancing the proposed tracker. The experimental results on challenging sequences show that the proposed algorithm is effective and performs favorably against 12 state-of-the-art trackers.
Auteurs: Yehui Yang;Wenrui Hu;Wensheng Zhang;Tianzhu Zhang;Yuan Xie;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 05.-2017, volume: 27, issue:5, pages: 1031 - 1042
Editeur: IEEE
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    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