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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 05-2017 trié par par titre, page: 3
» 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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» 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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» 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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» 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 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 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 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 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 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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» 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 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
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» 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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» 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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» Distributed Algorithms for Computation of Centrality Measures in Complex Networks
Résumé:
This paper is concerned with distributed computation of several commonly used centrality measures in complex networks. In particular, we propose deterministic algorithms, which converge in finite time, for the distributed computation of the degree, closeness and betweenness centrality measures in directed graphs. Regarding eigenvector centrality, we consider the PageRank problem as its typical variant, and design distributed randomized algorithms to compute PageRank for both fixed and time-varying graphs. A key feature of the proposed algorithms is that they do not require to know the network size, which can be simultaneously estimated at every node, and that they are clock-free. To address the PageRank problem of time-varying graphs, we introduce the concept of persistent graph, which eliminates the effect of spamming nodes. Moreover, we prove that these algorithms converge almost surely and in the sense of $L^p$. Finally, the effectiveness of the proposed algorithms is illustrated via extensive simulations using a classical benchmark.
Auteurs: Keyou You;Roberto Tempo;Li Qiu;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2080 - 2094
Editeur: IEEE
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» Distributed Algorithms to Compute Walrasian Equilibrium in Mobile Crowdsensing
Résumé:
In this paper, we consider joint pricing and task allocation in a unified mobile crowdsensing system, where all task initiators and mobile users are viewed as peers. From an exchange market point of view, the pricing and task allocation in such a unified system depend only on the supply and demand since no one can dominate the process, with the optimal solution being characterized by the Walrasian equilibrium. This is quite different from existing approaches, where each task initiator builds a specific mobile crowdsensing system and provides an incentive mechanism to maximize his/her own utility. We design distributed algorithms to compute the Walrasian equilibrium under the scenario where one cloud platform is available in the system. We propose to maximize social welfare of the whole system, and dual decomposition is then employed to divide the social welfare maximization problem into a set of subproblems that can be solved by task initiators and mobile users. We prove that the proposed algorithm converges to the optimal solution of social welfare maximization problem. Further, we show that the prices and task allocation obtained by the algorithm also yields a Walrasian equilibrium. Also, the proposed algorithm does not need the cloud to collect private information such as utility functions of task initiators and cost functions of mobile users. Extensive simulations demonstrate the effectiveness of the proposed algorithms.
Auteurs: Xiaoming Duan;Chengcheng Zhao;Shibo He;Peng Cheng;Junshan Zhang;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4048 - 4057
Editeur: IEEE
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» Distributed Continuous-Time Optimization: Nonuniform Gradient Gains, Finite-Time Convergence, and Convex Constraint Set
Résumé:
In this paper, a distributed optimization problem with general differentiable convex objective functions is studied for continuous-time multi-agent systems with single-integrator dynamics. The objective is for multiple agents to cooperatively optimize a team objective function formed by a sum of local objective functions with only local interaction and information while explicitly taking into account nonuniform gradient gains, finite-time convergence, and a common convex constraint set. First, a distributed nonsmooth algorithm is introduced for a special class of convex objective functions that have a quadratic-like form. It is shown that all agents reach a consensus in finite time while minimizing the team objective function asymptotically. Second, a distributed algorithm is presented for general differentiable convex objective functions, in which the interaction gains of each agent can be self-adjusted based on local states. A corresponding condition is then given to guarantee that all agents reach a consensus in finite time while minimizing the team objective function asymptotically. Third, a distributed optimization algorithm with state-dependent gradient gains is given for general differentiable convex objective functions. It is shown that the distributed continuous-time optimization problem can be solved even though the gradient gains are not identical. Fourth, a distributed tracking algorithm combined with a distributed estimation algorithm is given for general differentiable convex objective functions. It is shown that all agents reach a consensus while minimizing the team objective function in finite time. Fifth, as an extension of the previous results, a distributed constrained optimization algorithm with nonuniform gradient gains and a distributed constrained finite-time optimization algorithm are given. It is shown that both algorithms can be used to solve a distributed continuous-time optimization problem with a common convex constraint set. Numerical - xamples are included to illustrate the obtained theoretical results.
Auteurs: Peng Lin;Wei Ren;Jay A. Farrell;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2239 - 2253
Editeur: IEEE
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» Distributed Fiber-Optic Acoustic Sensor With Enhanced Response Bandwidth and High Signal-to-Noise Ratio
Résumé:
This paper proposes a novel distributed fiber-optic acoustic sensor, which can solve both the tradeoff between the maximum measurable distance and the spatial resolution, and that between the measurement distance and the vibration response bandwidth. The system is based on frequency-division-multiplexing time-gated digital optical frequency domain reflectometry, which consecutively injects linear-frequency-modulated probe pulses with different frequency ranges. Undersampling method is introduced to reduce the sampling rate of the analog-to-digital converter and the data size, which can reduce the cost of the system and facilitate real-time data processing. In experiments, two simultaneous vibrations with frequency up to 9 kHz are detected over the 24.7-km-long fiber, with a sign-to-noise ratio of 30 dB and spatial resolution of 10 m.
Auteurs: Dian Chen;Qingwen Liu;Xinyu Fan;Zuyuan He;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 2037 - 2043
Editeur: IEEE
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» Distributed Generation Monitoring for Hierarchical Control Applications in Smart Microgrids
Résumé:
Hierarchical control/protection applications in smart microgrids require knowledge of real-time status of distributed generation (DG) systems. Lack or failure of communications with the microgrid central controller (MGCC) can significantly undermine performance of such applications since the MGCC cannot determine the number of operational energy sources. To overcome these challenges, the MGCC needs a secondary mechanism in order to track presence or absence of DG systems. This paper proposes a new monitoring approach that empowers the MGCC to estimate the number of operational DG systems and thus determine the total generation capacity of the microgrid. A parameter estimator is developed to extract an autoregressive model for the synchrophasors of current symmetrical components (CSC) of the main point of common coupling (PCC). The extracted model is used by an adaptive algorithm that identifies abrupt changes in DG by evaluating the norm of forward prediction error. The proposed approach uses real-time synchrophasor data to dynamically update the criterion for event detection and is very robust against abrupt load changes. The performance is verified using extensive simulations of the IEEE 13-Bus benchmark with four photovoltaic (PV) units.
Auteurs: Younes Seyedi;Houshang Karimi;Santiago Grijalva;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2305 - 2314
Editeur: IEEE
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» Distributed Learning of Predictive Structures From Multiple Tasks Over Networks
Résumé:
This paper is concerned with the problem of distributed multitask learning over networks, which aims to simultaneously infer multiple node-specific parameter vectors in a collaborative manner. Most of the existing works on the distributed multitask problem modeled the task relatedness by assuming some similarities of parameter vectors in an explicit way. In this paper, we implicitly model the similarity of parameter vectors by assuming that the parameter vectors share a common low-dimensional predictive structure on hypothesis spaces, which is learned using the available data in networks. A distributed structure learning algorithm for the in-network cooperative estimation problem is then derived based on the block coordinate descent method integrated with the inexact alternating direction method of multipliers technique. Simulations on both synthetic and real-world datasets are given to verify the effectiveness of the proposed algorithm. In the case that each node shares a common predictive subspace, it is demonstrated that the proposed multitask algorithm outperforms the noncooperative learning algorithm. Moreover, the use of the inexact approach can significantly reduce the communication bandwidth and still provide the same optimal solution as the corresponding centralized approach.
Auteurs: Junhao Hua;Chunguang Li;Hui-Liang Shen;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4246 - 4256
Editeur: IEEE
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» Distributed LPV State-Feedback Control Under Control Input Saturation
Résumé:
Developed in this note is a scheduled state-feedback controller synthesis method for discrete-time Linear Parameter Varying (LPV) systems subjected to control input saturation constraints. The static state-feedback gain is scheduled with an exact replica of the parameter matrix. The saturation effect is modeled by introducing time-varying parameters as functions of the control inputs, which are also used to schedule the controller. The synthesis method is then specialized to distributed state-feedback by imposing a particular structure on the feedback gain matrix. An explicit formula is also derived for the computation of the distributed control input from a nonlinear equation. The viability of the proposed method is tested in a simulation environment, for a ramp meter traffic flow control problem.
Auteurs: Azita Dabiri;Balázs Kulcsár;Hakan Köroğlu;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2450 - 2456
Editeur: IEEE
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» Distributed Containment Maneuvering of Multiple Marine Vessels via Neurodynamics-Based Output Feedback
Résumé:
In this paper, a neurodynamics-based output feedback scheme is proposed for distributed containment maneuvering of marine vessels guided by multiple parameterized paths without using velocity measurements. Each vessel is subject to internal model uncertainties and external disturbances induced by wind, waves, and ocean currents. In order to recover unmeasured velocity information as well as to identify unknown vessel dynamics, an echo state network (ESN) based observer using recorded input–output data is proposed for each vessel. Based on the observed velocity information of neighboring vessels, distributed containment maneuvering laws are developed at the kinematic level. Next, in order to shape the transient motion profile for vessel kinetics to follow, finite-time nonlinear tracking differentiators are employed to generate smooth reference signals as well as to extract the time derivatives of kinematic control laws. Finally, ESN-based dynamic control laws are constructed at the kinetic level. The stability of the closed-loop system is analyzed via input-to-state stability and cascade theory. Simulation results are provided to illustrate the efficacy of the proposed neurodynamics-based output feedback approach.
Auteurs: Zhouhua Peng;Jun Wang;Dan Wang;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3831 - 3839
Editeur: IEEE
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» Distribution Systems Operation Considering Energy Storage Devices and Distributed Generation
Résumé:
In this paper, a non-linear programming model to operate distribution systems considering energy storage devices and distributed generation is presented. Mathematical formulation is made taking in to account four terms for minimization: The cost operation of the electrical grid, reducing greenhouse emissions, reduction of electrical losses in conductors and voltage profile improve. As model constraints are employed the active a reactive nodal power balance, maximum capacities from distributed generation and energy storage devices, and the voltage profile regulation. To solve the proposed mathematical model a commercial optimization software GAMS and CONOPT solver are employed. To verify the efficiency and applicability of the model developed are used two test nodes 9 and 10, which have been adapted to the typical operating conditions of Colombian distribution systems. The results show the ability to adapt to various conditions and operating instructions of the utility.
Auteurs: Oscar Danilo Montoya;Alejandro Grajales;Alejandro Garces;Carlos Alberto Castro;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 890 - 900
Editeur: IEEE
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» Disturbance-Adaptive Short-Term Frequency Support of a DFIG Associated With the Variable Gain Based on the ROCOF and Rotor Speed
Résumé:
This paper proposes a disturbance-adaptive short-term frequency support scheme of a doubly fed induction generator (DFIG) that can improve the frequency-supporting capability while ensuring stable operation. In the proposed scheme, the output of the additional control loop is determined as the product of the frequency deviation and adaptive gain, which is modified depending on the rate of change of frequency (ROCOF) and rotor speed. To achieve these objectives, the adaptive gain is set to be high during the early stage of a disturbance, when the ROCOF and rotor speed are high. Until the frequency nadir (FN), the gain decreases with the ROCOF and rotor speed. After the FN, the gain decreases only with the rotor speed. The simulation results demonstrate that the proposed scheme improves the FN and maximum ROCOF while ensuring the stable operation of a DFIG under various wind conditions irrespective of the disturbance conditions by adaptively changing the control gain with the ROCOF and rotor speed, even if the wind speed decreases and a consecutive disturbance occurs.
Auteurs: Min Hwang;Eduard Muljadi;Gilsoo Jang;Yong Cheol Kang;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1873 - 1881
Editeur: IEEE
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» Dive into IMS2017 Workshops and Short Courses!
Résumé:
Provides a notice of upcoming conference events of interest to practitioners and researchers.
Auteurs: Cynthia Hang;Yi-Chi Shih;Kevin Leong;Bryan Wu;Domine Leenaerts;Osama Shanaa;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 42 - 66
Editeur: IEEE
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» Diversity Study of a Frequency Selective Surface Transponder for Wearable Applications
Résumé:
This communication presents a semipassive radio frequency identification system in the 2.45-GHz Industrial, Scientific and Medical band. The transponder (or tag) is based on a modulated frequency selective surface (FSS). The FSS is composed of dipoles loaded with varactor diodes that modulate the radar cross section. The FSS transponder is designed to work for wearable and on-body applications and is used for reading and transmitting information from different sensors placed on the body. Experimental results locating the FSS at different positions in real scenarios and also at different places on the body are provided. Multiple FSSs have been used to explore spatial and polarization diversity techniques in order to mitigate the deep fadings that can happen during communication. Noticeable diversity gain has been obtained in both the cases without using antenna diversity in the reader. Finally, this communication describes a proof-of-concept experiment of the communication where two FSSs send digital data using a frequency shift keying modulation.
Auteurs: J. Lorenzo;A. Lazaro;R. Villarino;D. Girbau;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2701 - 2706
Editeur: IEEE
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» Diversity Through Adversity [President's Message]
Résumé:
Presents the President's message for this issue of the publication.
Auteurs: Rabab Ward;
Apparue dans: IEEE Signal Processing Magazine
Date publication: 05.-2017, volume: 34, issue:3, pages: 4 - 5
Editeur: IEEE
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» DOA and Gain-Phase Errors Estimation for Noncircular Sources With Central Symmetric Array
Résumé:
The problem of direction-of-arrival (DOA) estimation for noncircular sources impinging on a central symmetric array (CSA) in the presence of sensor gain-phase uncertainties is addressed in this paper. A noniterative method is proposed and the corresponding stochastic Cramér–Rao bound is derived. The proposed method is realized through two steps. First, an eigenstructure-based technique is presented to estimate the spatial signatures. Second, the DOAs are obtained by adopting an element-wise division approach to the estimated spatial signatures, based on which, the sensor gain-phase errors are given in closed-form. The ambiguity of DOA estimation is analyzed as well. The proposed method offers a number of advantages in comparison with the existing methods that apply to CSA. First, the DOA estimator is independent of the sensor phases. Second, the proposed method applies to incoherent sources. Third, the proposed method is capable of providing 360° azimuthal coverage under certain conditions. Fourth, an additional performance gain is achieved by taking the property of noncircular sources into consideration. Numerical simulations are provided to verify the effectiveness of the proposed method.
Auteurs: Wei Xie;Changsheng Wang;Fei Wen;Jiangbo Liu;Qun Wan;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3068 - 3078
Editeur: IEEE
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» Domain Decomposition Approach for Efficient Time-Domain Finite-Element Computation of Winding Losses in Electrical Machines
Résumé:
Finite-element (FE) analysis of winding losses in electrical machines can be computationally uneconomical. Computationally lighter methods often place restrictions on the winding configuration or have been used for time-harmonic problems only. This paper proposes a domain decomposition-type approach for solving this problem. The slots of the machine are modeled by their impulse response functions and coupled together with the rest of the problem. The method places no restrictions on the winding and naturally includes all resistive ac loss components. The method is then evaluated on a 500-kW induction motor. According to the simulations, the method yields precise results 70–100 faster compared with the established FE approach.
Auteurs: Antti Lehikoinen;Jouni Ikäheimo;Antero Arkkio;Anouar Belahcen;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 9
Editeur: IEEE
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» Don't fool Me!: Detection, Characterisation and Diagnosis of Spoofed and Masked Events in Wireless Sensor Networks
Résumé:
Wireless Sensor Networks carry a high risk of being compromised, as their deployments are often unattended, physically accessible and the wireless medium is difficult to secure. Malicious data injections take place when the sensed measurements are maliciously altered to trigger wrong and potentially dangerous responses. When many sensors are compromised, they can collude with each other to alter the measurements making such changes difficult to detect. Distinguishing between genuine and malicious measurements is even more difficult when significant variations may be introduced because of events, especially if more events occur simultaneously. We propose a novel methodology based on wavelet transform to detect malicious data injections, to characterise the responsible sensors, and to distinguish malicious interference from faulty behaviours. The results, both with simulated and real measurements, show that our approach is able to counteract sophisticated attacks, achieving a significant improvement over state-of-the-art approaches.
Auteurs: Vittorio P. Illiano;Luis Muñoz-González;Emil C. Lupu;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 05.-2017, volume: 14, issue:3, pages: 279 - 293
Editeur: IEEE
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» Downlink and Uplink Decoupling in Two-Tier Heterogeneous Networks With Multi- Antenna Base Stations
Résumé:
In order to improve the uplink performance of future cellular networks, the idea to decouple the downlink (DL) and uplink (UL) association has recently been shown to provide significant gain in terms of both coverage and rate performance. However, all the works are limited to a single input single output (SISO) network. Therefore, to study the gain provided by the DL and UL decoupling in multi-antenna base stations (BSs) setup, we study a two tier heterogeneous network consisting of multi-antenna BSs, and single antenna user equipments (UEs). We use maximal ratio combining (MRC) as a linear receiver at the BSs and tools from stochastic geometry, and we derive tractable expressions for both signal-to-interference ratio (SIR) coverage probability and rate coverage probability. We observe that as the disparity in the beamforming gain of both tiers increases, the gain in terms of SIR coverage probability provided by the decoupled association over non-decoupled association decreases. We further observe that when there is asymmetry in the number of antennas of both tiers, then we need further biasing toward femto-tier on the top of decoupled association to balance the load and get optimal rate coverage probability.
Auteurs: Mudasar Bacha;Yueping Wu;Bruno Clerckx;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2760 - 2775
Editeur: IEEE
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» Dr. Taylor's X-Ray machine [Past Forward]
Résumé:
When it was completed in 1940, the 1.4-million-volt X-ray generator at the U.S. National Bureau of Standards was the most powerful in the world. In this photo from 1959, Lauriston S. Taylor, chief of the agency’s X-ray section, stands in front of a chalkboard showing tissue doses that have been carefully calculated to either keep humans safe or give them superpowers.
Auteurs: Evan Ackerman;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 56 - 56
Editeur: IEEE
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» Drivable Road Reconstruction for Intelligent Vehicles Based on Two-View Geometry
Résumé:
This paper presents a road reconstruction algorithm based on two-view geometry. A general geometric model for both planar and nonplanar scenes is proposed with respect to a reference plane. Then, points in the scene can be described geometrically by the projective parallax with respect to the reference plane. In practice, the grounding plane of the vehicle is selected as the reference plane. A row-wise image registration method is proposed to estimate the parallax information effectively. Based on the geometric model, points in the scene can be reconstructed as relative position and height information with respect to the reference plane. For road detection, the scene can be segmented where the height changes abruptly. Then, the road region is obtained by a diffusion strategy. The road surface can be reconstructed using the proposed model. Experiments are conducted to show the effectiveness and robustness of the proposed approach. The proposed approach is general in the sense that it does not rely on the priors of road appearance and structure, and it is not restricted to specific stereo camera configurations making it extendable to other multicamera systems.
Auteurs: Bingxi Jia;Jian Chen;Kaixiang Zhang;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3696 - 3706
Editeur: IEEE
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» Driver-Automation Cooperative Approach for Shared Steering Control Under Multiple System Constraints: Design and Experiments
Résumé:
This paper addresses the shared lateral control between a human driver and a lane keeping assist system of intelligent vehicles for both lane keeping and obstacle avoidance. This control issue is very challenging in today's automotive industry due to the human–machine interaction involved in the control design. In this paper, we propose a new approach to consider such an interaction via a fictive driver activity parameter introduced into the road–vehicle system. Hence, the steering assistance actions can be computed according to the driver's real-time behaviors. The Takagi–Sugeno fuzzy control approach is proposed to deal with the time-varying driver activity parameter and vehicle speed. Especially, the concept of robust invariant set is exploited using Lyapunov arguments to handle theoretically both system state and control input limitations. Considering these system constraints in the control design procedure aims to improve the driver's safety and comfort. Experimental tests with a human driver and an advanced interactive dynamic driving simulator are conducted to show the effectiveness of the proposed method.
Auteurs: Anh-Tu Nguyen;Chouki Sentouh;Jean-Christophe Popieul;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3819 - 3830
Editeur: IEEE
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» Dual Band Metamaterial Cherenkov Oscillator With a Waveguide Coupler
Résumé:
We propose a waveguide coupler based on a metamaterial slow-wave structure (SWS) and then present a dual band metamaterial Cherenkov oscillator. The high-frequency characteristics of the SWS are studied by High Frequency Structure Simulator, indicating that both $n = 0$ space harmonic of fundamental mode and $n = -1$ space harmonic of first higher order mode exhibit “backward” wave properties and high interaction impedances. Meanwhile, the transmission property of the metamaterial SWS with the waveguide couplers is investigated. The simulation results show two passbands, which are verified by the experiment. In addition, we use linear theory to predict the starting currents, which are verified by Computer Simulation Technology (CST) Particle-In-Cell (PIC) simulation. Furthermore, the performance of the dual band metamaterial Cherenkov oscillator is studied using the CST PIC solver. The results show that the electronic efficiency of the proposed oscillator reaches 52% and its tuning bandwidths are ~7 and ~30 MHz for Modes 1 and 2, respectively. The CST PIC simulation results agree well with those using the Computer-aided highly efficient electromagnetic particle-in-cell code. These results indicate that the proposed oscillator has small size, dual band property, and high electronic efficiency.
Auteurs: Xianfeng Tang;Zhaoyun Duan;Xinwu Ma;Shifeng Li;Fei Wang;Yuanyuan Wang;Yubin Gong;Jinjun Feng;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2376 - 2382
Editeur: IEEE
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» Dual-Mode Branch-Line/Rat-Race Coupler Using Composite Right-/Left-Handed Lines
Résumé:
A novel dual-operational mode directional coupler, functioning as a branch-line coupler at one frequency but identically to a rat-race coupler in the other one, is proposed and investigated. To fulfill the unusual design, the characteristic impedance and phase response of a conventional composite right-/left-handed line are controlled simultaneously at both operating frequencies. Analytical design equations are derived and verified by experimental results. The dual-mode coupler shows typical responses of a 90° and 180° coupler, respectively, in the first and second (1.5/2.5 GHz) operating bands. The fractional bandwidths are 8% and 16%.
Auteurs: Li Chang;Tzyh-Ghuang Ma;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 449 - 451
Editeur: IEEE
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» Dual-Parameters Optical Fiber Sensor With Enhanced Resolution Using Twisted MMF Based on SMS Structure
Résumé:
A compact and low cost optical fiber sensor by introducing higher order modes interference with fiber twisting based on single-mode-multimode-single-mode structure is proposed and demonstrated for simultaneous measurement of strain and temperature. The sensor is fabricated by heating and twisting a section of multimode fiber (MMF), which is spliced between two single-mode fibers. By adjusting the heating temperature and rotate speed during fabrication, the twisted region is introduced in MMF, which is able to couple more power of light into the cladding and introduce higher order modes in modal interferences. With this method, strain sensitivity of −7 and −2.19 pm/ $mu varepsilon $ as well as temperature sensitivity of 17.33 and 13 pm/°C are obtained. By spatial frequency demodulation method, measurement resolution reaches $pm 2.14~mu varepsilon $ and ±0.89 °C, which has great potential in dual-parameters measurement of temperature and strain with high resolution.
Auteurs: Yuan Sun;Deming Liu;Ping Lu;Qizhen Sun;Wei Yang;Shun Wang;Li Liu;Jiangshan Zhang;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3045 - 3051
Editeur: IEEE
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» Dynamic Analysis of a Novel Moving Magnet Linear Actuator
Résumé:
A novel moving magnet linear actuator is proposed for linear oscillations in the linear resonant compressors for household refrigerators. This paper provides stator and armature design including CAD model and geometric parameters. Furthermore, the working principle of the proposed actuator is explained. The stator assembly is composed of two reversely wound coils, which are electrically excited with single phase ac power and oscillates the radially magnetized armature. With the help of the electromechanical analytical model, the dynamic parameters such as stroke, velocity, and acceleration of the armature are derived. Additionally, the time-dependent current model of the stator winding is proposed. An experimental setup is used to validate these responses at the resonance excitation frequency with the help of sensors. The system kinetics are discussed to estimate the spring, damping, inertial, and magnetic forces. A simulation is executed to estimate the time-domain responses of these dynamic parameters and the effects of excitation frequency are discussed. The force models are experimentally validated at the resonance frequency excitation. In order to evaluate the performance of the proposed actuator, a comparison of the performance parameters, such as efficiency, stroke, current, and mass flow rate is demonstrated with the conventional rotary as well as the linear motors for linear compressor application.
Auteurs: Adnan Hassan;Armin Bijanzad;Ismail Lazoglu;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3758 - 3766
Editeur: IEEE
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» Dynamic Appliances Scheduling in Collaborative MicroGrids System
Résumé:
In this paper, a new approach that is based on a collaborative system of MicroGrids (MGs) is proposed to enable household appliance scheduling. To achieve this, appliances are categorized into flexible and non-flexible deferrable loads (DLs), according to their electrical components. We propose a dynamic scheduling algorithm where users can systematically manage the operation of their electric appliances. The main challenge is to develop a flattening function calculus (reshaping) for both flexible and non-flexible DLs. In addition, implementation of the proposed algorithm would require dynamically analyzing two successive multiobjective optimization (MOO) problems. The first one targets the activation schedule of non-flexible DLs and the second one deals with the power profiles of flexible DLs. The MOO problems are resolved by using a fast and elitist multiobjective genetic algorithm (NSGA-II). Finally, in order to show the efficiency of the proposed approach, a case study of a collaborative system that consists of 40 MGs registered in the load curve for the flattening program has been developed. The results verify that the load curve can indeed become very flat by applying the proposed scheduling approach.
Auteurs: Hasnae Bilil;Ghassane Aniba;Hamid Gharavi;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2276 - 2287
Editeur: IEEE
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» Dynamic Binary Translation of VLIW Codes on Scalar Architectures
Résumé:
Many of the recently announced integrated manycore architectures targeting specific applications embed several, if not many, very long instruction word (VLIW) processors. To start developing software while the hardware is still being designed, virtual prototypes of the full system are commonly used. Fast processor simulation is thus a requirement. To that aim, this paper introduces a strategy to perform dynamic binary translation (DBT) of VLIW codes on scalar architectures. We propose a high level simulation algorithm which takes into account VLIW oddities, such as explicit instruction parallelism, instructions with non unit register update latency, and delayed slots in branches. We present the implementation details of this algorithm within a DBT environment, as it raises many corner cases that are irrelevant in scalar DBT. Our experiments confirm that our solution is functionally correct, and show speedups of 1 and 2 orders of magnitude compared to raw instruction interpretation, even though no optimizations were performed on the code during and after translation.
Auteurs: Luc Michel;Frédéric Pétrot;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 789 - 800
Editeur: IEEE
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» Dynamic Facet Ordering for Faceted Product Search Engines
Résumé:
Faceted browsing is widely used in Web shops and product comparison sites. In these cases, a fixed ordered list of facets is often employed. This approach suffers from two main issues. First, one needs to invest a significant amount of time to devise an effective list. Second, with a fixed list of facets, it can happen that a facet becomes useless if all products that match the query are associated to that particular facet. In this work, we present a framework for dynamic facet ordering in e-commerce. Based on measures for specificity and dispersion of facet values, the fully automated algorithm ranks those properties and facets on top that lead to a quick drill-down for any possible target product. In contrast to existing solutions, the framework addresses e-commerce specific aspects, such as the possibility of multiple clicks, the grouping of facets by their corresponding properties, and the abundance of numeric facets. In a large-scale simulation and user study, our approach was, in general, favorably compared to a facet list created by domain experts, a greedy approach as baseline, and a state-of-the-art entropy-based solution.
Auteurs: Damir Vandic;Steven Aanen;Flavius Frasincar;Uzay Kaymak;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 05.-2017, volume: 29, issue:5, pages: 1004 - 1016
Editeur: IEEE
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» Dynamic Fuzzy Cognitive Maps Applied in Realibility Centered Maintanance of Electric Motors
Résumé:
The industry has systems and machines that need to operate within appropriate parameters to ensure quality in production. In this context it is necessary to maintain, through maintenance, the conditions necessary for proper operation. Thus, through the Reliability Centered Maintenance with quantitative feedback by Fuzzy Cognitive Maps applied to electric motors, can suggest a better reliability, proposal of this research. This paper discusses the Reliability Centered Maintenance (RCM) with reference to a generic Check list of electric motors' maintenance. Through the maintenance actions for correction of faults and/or defects, it can be modeled a critical and qualitative FCM that will present a quantitative diagnosis aimed at a proposal for a computational tool to assist in the maintenance management, adding improvements to the system
Auteurs: Marcio Mendonca;Ivan Rossato Chun;Michelle Eliza Casagrande Rocha;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 827 - 834
Editeur: IEEE
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» Dynamic Strain Measurement Using Small Gain Stimulated Brillouin Scattering in STFT-BOTDR
Résumé:
A distributed dynamic strain measurement is demonstrated using small gain stimulated Brillouin scattering (SBS) in Brillouin optical time domain reflectometry based on the short-time Fourier transform algorithm. The input power limits, frequency uncertainties for given pulse durations, fiber lengths, and the number of averaging are calculated. The output signal power and the signal-to-noise ratio of the system output are enhanced by SBS. It is found that the signal processing is faster and requires fewer averaging to achieve dynamic sensing performance along the fiber under test. A 60-Hz vibration on a 6-m fiber section at the end of a 935-m fiber is detected with the spatial resolution of 4 m with a sampling rate of 2.5 kS/s.
Auteurs: Bo Li;Linqing Luo;Yifei Yu;Kenichi Soga;Jize Yan;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2718 - 2724
Editeur: IEEE
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» Dynamic Subarrays for Hybrid Precoding in Wideband mmWave MIMO Systems
Résumé:
Hybrid analog/digital precoding architectures can address the tradeoff between achievable spectral efficiency and power consumption in large-scale MIMO systems. This makes them a promising candidate for millimeter wave systems, which deploy large antenna arrays at both the transmitter and the receiver to guarantee sufficient received signal power. Most prior work on hybrid precoding focused on narrowband channels and assumed fully connected hybrid architectures. Millimeter wave (mmWave) systems, though, are expected to be wideband with frequency selectivity. In this paper, a closed-form solution for fully connected OFDM-based hybrid analog/digital precoding is developed for frequency selective mmWave systems. This solution is then extended to partially connected but fixed architectures in which each RF chain is connected to a specific subset of the antennas. The derived solutions give insights into how the hybrid subarray structures should be designed. Based on this, a novel technique that dynamically constructs the hybrid subarrays knowing the long-term channel characteristics is developed. Simulation results show that the proposed hybrid precoding solutions achieve spectral efficiencies close to that obtained with fully digital architectures in wideband mmWave channels. Furthermore, the results indicate that the developed dynamic subarray solution outperforms the fixed hybrid subarray structures in various system and channel conditions.
Auteurs: Sungwoo Park;Ahmed Alkhateeb;Robert W. Heath;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2907 - 2920
Editeur: IEEE
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» Dynamic Variable Time-Stepping Schemes for Real-Time FPGA-Based Nonlinear Electromagnetic Transient Emulation
Résumé:
Electromagnetic transient (EMT) simulation of nonlinear elements in power systems is a particular challenge due to the requirements of an accurate representation and an efficient solution. The existing real-time simulators utilize a piecewise linear representation along with a fixed time step for the solution of nonlinear elements. This paper proposes the detailed methodologies for applying variable time stepping to real-time EMT simulation to improve the simulation accuracy and efficiency. The challenges, the feasible solutions, and corresponding restrictions of applying various variable time-stepping schemes along with nonlinear element solution methods in real time are discussed. The offline simulation and the real-time hardware emulation of two case studies, a full-bridge diode circuit and a power transmission system, are presented. The case studies were implemented on the field-programmable gate array device (Xilinx Virtex-7 XC7VX485T) in real time using high-level synthesis tool to achieve a parallelized and pipelined hardware design with minimum coding effort. The real-time emulation results captured by an oscilloscope are validated against the offline simulation on Saber and PSCAD/EMTDC software tools.
Auteurs: Zhuoxuan Shen;Venkata Dinavahi;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4006 - 4016
Editeur: IEEE
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» Dynamic Whitening Saliency
Résumé:
General dynamic scenes involve multiple rigid and flexible objects, with relative and common motion, camera induced or not. The complexity of the motion events together with their strong spatio-temporal correlations make the estimation of dynamic visual saliency a big computational challenge. In this work, we propose a computational model of saliency based on the assumption that perceptual relevant information is carried by high-order statistical structures. Through whitening, we completely remove the second-order information (correlations and variances) of the data, gaining access to the relevant information. The proposed approach is an analytically tractable and computationally simple framework which we call Dynamic Adaptive Whitening Saliency (AWS-D). For model assessment, the provided saliency maps were used to predict the fixations of human observers over six public video datasets, and also to reproduce the human behavior under certain psychophysical experiments (dynamic pop-out). The results demonstrate that AWS-D beats state-of-the-art dynamic saliency models, and suggest that the model might contain the basis to understand the key mechanisms of visual saliency. Experimental evaluation was performed using an extension to video of the well-known methodology for static images, together with a bootstrap permutation test (random label hypothesis) which yields additional information about temporal evolution of the metrics statistical significance.
Auteurs: Víctor Leborán;Antón García-Díaz;Xosé R. Fdez-Vidal;Xosé M. Pardo;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 05.-2017, volume: 39, issue:5, pages: 893 - 907
Editeur: IEEE
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» E Komo Mai from the IMS2017 General Chair
Résumé:
Provides a notice of upcoming conference events of interest to practitioners and researchers.
Auteurs: Wayne Shiroma;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 16 - 22
Editeur: IEEE
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» Earphone showdown, part 2 - The DQSM D2, LKER I8, and Crazy Cello [Resources_Review]
Résumé:
More than a year ago I noticed I was spending most of my music-listening time playing songs on my smartphone. That realization sent me on a quest to find the most inexpensive earphone-based setup that would give me high-end, audiophile sound. I listened to dozens of earphones, half a dozen headphone amplifiers, and a like number of digital-to-analog converter-headphone amplifiers (DAC-headphone amplifiers). I found a few gems, such as the DragonFly Red DAC-headphone amplifier from Audioquest, in Irvine, Calif.
Auteurs: Glenn Zorpette;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 23 - 23
Editeur: IEEE
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» Economic Dispatch Under Uncertainty: The Probabilistic Envelopes Approach
Résumé:
With fast-paced renewable energy integration, stochastic methods are emerging as a viable alternative to traditional power system operations planning under uncertainty. The value of stochastic planning lies in its effectiveness at reducing operational costs while allowing higher penetration levels of renewable sources, and without much sacrifice to system security. This is under the premise that the decision maker may not need to fully hedge against more extreme and costlier events that exhibit lower probabilities of occurrence. On the other hand, stochastic methods do suffer from the curse of dimensionality, which renders them computationally intractable for practical application. Here, we propose a novel hybrid robust-stochastic approach based on the flexibility envelopes concept. It circumvents the curse of dimensionality by using probability weighted envelopes to enclose the evolution of the net load uncertainty over the planning horizon. The new approach is illustrated by a receding-horizon economic dispatch example, to compare its effectiveness to robust planning and stochastic planning with a scenario tree.
Auteurs: Hussam Nosair;François Bouffard;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1701 - 1710
Editeur: IEEE
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» Edge Popularity Prediction Based on Social-Driven Propagation Dynamics
Résumé:
Caching contents in edge networks can reduce latency and lighten the burden on backhaul links. Since the capacity of cache nodes is limited, accurate content popularity distribution is crucial to the effectual usage of cache capacity. However, existing popularity prediction models stem from big data and, hence, may suffer poor accuracy due to the small population in edge caching. In this letter, we propose a social-driven propagation dynamics-based prediction model, which requires neither training phases nor prior knowledge. Specifically, we first explore social relationships to bridge the gap between small population and prediction accuracy under susceptible-infected-recovery model. Then, a discrete-time markov chain approach is proposed to predict the viewing probability of certain contents from the perspective of individuals. Simulations validate that our proposed model outperforms other solutions significantly, by improving up to 94% in accuracy and 99% less runtime overhead.
Auteurs: Shuo He;Hui Tian;Xinchen Lyu;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1027 - 1030
Editeur: IEEE
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» Editorial
Résumé:
Presents an editorial on the importance of supporting and mentoring female engineers.
Auteurs: Hulya Kirkici;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 05.-2017, volume: 33, issue:3, pages: 4 - 5
Editeur: IEEE
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» Editorial for May 2017 Issue
Résumé:
Pressents the introductory editorial for this issue of the publication.
Auteurs: RAJIV SABHERWAL;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 05.-2017, volume: 64, issue:2, pages: 117 - 119
Editeur: IEEE
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» Editorial Inaugural Issue of the “Journal-Within-a-Journal” on Microwave Systems and Applications
Résumé:
The globalization of the microwave and RF application space and commercial market has led to a situation in which no microwave engineer can remain solely focused on component design. Modern engineers now use complex CAD tools that allow them to reach deep into many aspects of system design as well, and refine their designs to improve overall system performance. Although radio communications were at the origin of RF technologies in the late nineteenth century and the first two decades of the twentieth century, the system-level design has embraced many more applications of RF and microwave technologies, such as radar, sensing, heating, and imaging.
Auteurs: José Carlos Pedro;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1649 - 1649
Editeur: IEEE
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» Editorial to the regular issue
Résumé:
This is the 5st issue of the IEEE Latin America Transactions of the year 2017. Volume 15 Issue 5, Mayl 2017
Auteurs: Mirela Sechi Moretti Annoni Notare;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 769 - 778
Editeur: IEEE
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» Editorial: A Message from the Incoming Editor-in-Chief
Résumé:
Presents the introductory editorial for this issue of the publication.
Auteurs: Marwan Krunz;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1199 - 1202
Editeur: IEEE
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» EEG-Informed Attended Speaker Extraction From Recorded Speech Mixtures With Application in Neuro-Steered Hearing Prostheses
Résumé:
Objective: We aim to extract and denoise the attended speaker in a noisy two-speaker acoustic scenario, relying on microphone array recordings from a binaural hearing aid, which are complemented with electroencephalography (EEG) recordings to infer the speaker of interest. Methods: In this study, we propose a modular processing flow that first extracts the two speech envelopes from the microphone recordings, then selects the attended speech envelope based on the EEG, and finally uses this envelope to inform a multichannel speech separation and denoising algorithm. Results: Strong suppression of interfering (unattended) speech and background noise is achieved, while the attended speech is preserved. Furthermore, EEG-based auditory attention detection (AAD) is shown to be robust to the use of noisy speech signals. Conclusions: Our results show that AAD-based speaker extraction from microphone array recordings is feasible and robust, even in noisy acoustic environments, and without access to the clean speech signals to perform EEG-based AAD. Significance: Current research on AAD always assumes the availability of the clean speech signals, which limits the applicability in real settings. We have extended this research to detect the attended speaker even when only microphone recordings with noisy speech mixtures are available. This is an enabling ingredient for new brain–computer interfaces and effective filtering schemes in neuro-steered hearing prostheses. Here, we provide a first proof of concept for EEG-informed attended speaker extraction and denoising.
Auteurs: Simon Van Eyndhoven;Tom Francart;Alexander Bertrand;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 1045 - 1056
Editeur: IEEE
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» Effect of External Magnetic Field Loaded at the Initial Period of Inertial Stretching Stage on the Stability of Shaped Charge Jet
Résumé:
In this paper, the effect of external magnetic field loaded at the initial period of inertial stretching stage on a jet produced by Ø56-mm shaped charge is evaluated through the depth-of-penetration (DOP) test method. Experimental results are compared with the results obtained under the field loaded at the later inertial stretching stage. A standoff of 650 mm is used in the experiments, in which the shaped charge jet can undergo formation, elongation, breakup, rotation, and drift. The initial energy is provided by a capacitor bank, which is loaded on the solenoid to generate a magnetic field used for coupling with the jet. The external magnetic field loaded at the initial period of inertial stretching stage can enhance the stability of the jet and increase its DOP. The penetration capability of the jet in the above-mentioned condition is increased by 77.4%.
Auteurs: Bin Ma;Zhengxiang Huang;Qiangqiang Xiao;Xudong Zu;Xin Jia;Long Ji;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 875 - 881
Editeur: IEEE
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» Effect of In and Zn Content on Structural and Electrical Properties of InZnSnO Thin-Film Transistors Using an Yb2TiO5 Gate Dielectric
Résumé:
In this paper, we investigated the effect of In and Zn content on the structural properties and electrical characteristics of amorphous indium–zinc–tin oxide ( $alpha $ -InZnSnO) thin-film transistors (TFTs) featuring an Yb2TiO5 gate dielectric. The Yb2TiO5 $alpha $ -InZnSnO TFT prepared at the 30-W condition exhibited better electrical characteristics in terms of a low threshold voltage of 0.52 V, a high ${I}_{{ mathrm{scriptscriptstyle ON}}}/{I}_{{ mathrm{scriptscriptstyle OFF}}}$ ratio of $1.1times 10^{8}$ , a low subthreshold swing of 203 mV/decade, and a large field-effect mobility of 27.9 cm2/Vs. We attribute these results to the optimal Zn and Sn content on InZnSnO channel forming a smooth surface and thus reducing density of interface states at the oxide/channel interface.
Auteurs: Tung-Ming Pan;Bo-Jung Peng;Jim-Long Her;Bih-Show Lou;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2233 - 2238
Editeur: IEEE
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» Effect of Mechanical Strain on Hydrogenated Amorphous Silicon Thin-Film Transistors and Compensation Circuits on Flexible Substrates
Résumé:
Hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) compensation pixel circuits were fabricated on polyethylene naphthalate substrates at amax-imumtemperature of 170 °C. The typical a-Si:H TFTs showed a field-effect mobility ( $mu _{text {FE}}$ ) of 0.8–1.1 cm $^{2}$ /Vs, a threshold voltage ( ${V}_{T}$ ) of 2–3.3 V, a subthreshold swing (SS) of ~0.65 V/decade, and an ON/OFF current ratio of $10^{7}$ $10^{8}$ . Under DC gate-bias stress without compensation, the TFT drive current decreased by ~50% withoutmechanical strain and ~60% with applied tensile strain. The TFT circuits effectively compensated for the change in the TFT drive current to within 10% of the original drive current value under mechanically strained and unstrained states. The orientation of the TFT within the circuit was found to affect the circuit compensation; TFTs having a channel length perpendicular to the mechanical strain were found to have a 50% higher threshold voltage shift ( $Delta {V}_{T}$ ) compared to devices parallel to the applied strain.
Auteurs: Czang-Ho Lee;Nikolas P. Papadopoulos;Manoj Sachdev;William S. Wong;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2016 - 2021
Editeur: IEEE
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» Effect of Quality Factor on Determining the Optimal Position of a Transmitter in Wireless Power Transfer Using a Relay
Résumé:
In this letter, the optimal placement of a transmitter is investigated under a given arrangement of a relay and a receiver for nonradiative wireless power transfer. Specifically, a closed-form equation is derived for the optimal coupling coefficient between the transmitter and the relay using an equivalent circuit model. Based on this theoretical analysis, it is found that the quality factor of the transmitter has a great effect on determining its optimal placement. In particular, the transmission efficiency can be improved by locating the resonator with a smaller quality factor (e.g., transmitter or receiver) closer to the relay. In order to support the validity of the analysis, the resonators, including the relay, receiver, and three different types of transmitters, are experimentally designed and fabricated. It is shown that our analytical results are well matched with the measured ones in various settings.
Auteurs: Kisong Lee;Sung Ho Chae;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 521 - 523
Editeur: IEEE
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» Effective Nonlinear Surface Impedance of Conductive Magnetic Slabs
Résumé:
A new formula is developed for the surface impedance of a nonlinear magnetic conductive semi-infinite slab. The impedance expression allows for proper incorporation of the nonlinear characteristic of the magnetic material, also using an analytical expression. Thus, the usual step representation of the $B$ $H$ curve is superseded. Normal and tangential magnetic components may simultaneously exist, avoiding the classical premise that only the tangential component exists. This way, it is possible to represent highly magnetic permeable materials where the normal component of the magnetic field is the main one. Our analytical formulation and solution can be for example used for calculation of losses in electrical machines or along with FE software code to avoid meshing of magnetic conductive regions.
Auteurs: Rafael Escarela-Perez;Serguei Maximov;Juan Carlos Olivares-Galvan;Enrique Melgoza;M. A. Arjona;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 12
Editeur: IEEE
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» Effective Richardson Constant of Sol-Gel Derived TiO2 Films in n-TiO2/p-Si Heterojunctions
Résumé:
The effective Richardson constant of sol–gel derived TiO2 thin film has been estimated possibly for the first time from temperature-dependent current–voltage ( ${I}$ ${V}$ ${T}$ ) characteristics of p-Si/n-TiO2 thin-film heterojunction diode by including the barrier height inhomogeneity at p-Si/n-TiO2 interface. The thermionic emission theory-based ${I}$ ${V}$ ${T}$ characteristics have been modified by assuming a Gaussian distributed barrier height at the heterojunction interface. The Richardson plot shows a nearly ideal Richardson constant of ~1265.57 Acm−2K−2, which is not only very close to its theoretical value of ~1200 Acm−2K−2 for n-TiO2 (with ${m} ^{ast }_{n}= 10 {m} _{0}$ ), but also the first result reported.
Auteurs: Gopal Rawat;Hemant Kumar;Yogesh Kumar;Chandan Kumar;Divya Somvanshi;Satyabrata Jit;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 633 - 636
Editeur: IEEE
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» Effective Self Adaptive Multiple Source Localization Technique by Primal Dual Interior Point Method in Binary Sensor Networks
Résumé:
Wireless sensor networks are creating a new era of pervasive computing applications, such as various monitoring and tracking system. The sensor network consists of so many tiny sensor nodes that have so many critical challenges, since they are battery operated and have limited processing capabilities. Binary sensor networks are modeled in a way that the sensor nodes can communicate with the only 1 b of information. One of the challenges in a binary sensor network is to localize the multiple sources. Very few works have been done considering this challenge. Localization failure may cause the whole system useless. We propose a multiple source localization method. We convert the localization problem into an optimization problem, and we solve that optimization problem using primal dual interior point method. Simulation results show that our proposed method provides better performance in every perspective compared with the existing works.
Auteurs: Muhidul Islam Khan;Kewen Xia;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1119 - 1122
Editeur: IEEE
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» Effectively Interpreting Discrete Wavelet Transformed Signals [Lecture Notes]
Résumé:
Following two decades of research focusing on the discrete wavelet transform (DWT) and driven by students' high level of questioning, I decided to write this essay on one of the most significant tools for time-frequency signal analysis. As it is widely applicable in a variety of fields, I invite readers to follow this lecture note, which is specially dedicated to show a practical strategy for the interpretation of DWT-based transformed signals while extracting useful information from them. The particular focus resides on the procedure used to find the time support of frequencies and how it is influenced by the wavelet family and the support size of corresponding filters.
Auteurs: Rodrigo Capobianco Guido;
Apparue dans: IEEE Signal Processing Magazine
Date publication: 05.-2017, volume: 34, issue:3, pages: 89 - 100
Editeur: IEEE
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» Effects of Channel Layer Thickness on Characteristics of Flexible Nickel-Doped Zinc Oxide Thin-Film Transistors
Résumé:
We have fabricated fully transparent high performance flexible nickel-doped zinc oxide thin-film transistors (NZO TFTs) on flexible plastic substrates using magnetron sputtering. The effects of active layer thickness on the performance of NZO TFTs was investigated. We found that the channel layer thickness has a notable influence on the characteristics of NZO TFTs. The electrical characteristics of NZO TFTs reached the optimization when the active channel layer thickness was 71 nm, with a low off-current lower than 1 pA, a high on/off drain current ratio of $ {2.1} times {10}^{9}$ , a high saturation mobility of 27.5 cm $^{2}cdot {mathrm {V}}^{-1}cdot {mathrm {s}}^{-1}$ , a steeper subthreshold swing of 67 mV/decade, and a low threshold voltage of 1.88 V. It is demonstrated that NZO is a promising active channel layer materials for future transparent flexible displays.
Auteurs: Dedong Han;Lingling Huang;Wen Yu;Yingying Cong;Junchen Dong;Xing Zhang;Yi Wang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 1997 - 2000
Editeur: IEEE
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» Effects of Gd2O3 Gate Dielectric on Proton-Irradiated AlGaN/GaN HEMTs
Résumé:
AlGaN/GaN high electron mobility transistors (HEMTs) and MOS-HEMTs using Gd2O3 as gate dielectric were irradiated with 2-MeV protons up to fluence of $1 times 10^{15}$ cm−2. Results showed that proton irradiation causes a strong degradation in the Schottky gate devices, featured by more than three orders of magnitude increase in reverse leakage current, a 30% decrease in maximum drain current, and the same percentage of increase in ON-resistance, respectively. Scanning transmission electron microscopy showed that radiation induced a diffusion of Ni into Au in the gate and void formation, degrading the transistors’ characteristics. The Gd2O3 gate dielectric layer prevented this diffusion and void formation. MOS-HEMTs with Gd2O3 gate dielectric show 50% less decrease of performance under proton irradiation than Schottky gate HEMTs (conventional HEMTs). The trapping effects of Gd2O3 gate layer before and after irradiation are also discussed.
Auteurs: Z. Gao;M. F. Romero;A. Redondo-Cubero;M. A. Pampillón;E. San Andrés;F. Calle;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 611 - 614
Editeur: IEEE
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» Effects of Ni in Strontium Titanate Nickelate Thin Films for Flexible Nonvolatile Memory Applications
Résumé:
This paper investigated the performance of flexible resistive random access memory devices based on simple spin-coated sol–gel-derived strontium titanate nickelate (STN) thin films on polyethylene terephthalate substrate. A high on/off ratio of $10^{5}$ and a uniform current distribution were demonstrated. The strong bonding between bidentate ligands of nickel (II) acetylacetone and titanium metal ion enabled the chelation effect, which contributed to the stability of the STN thin film, especially for moisture resistivity. Fourier transform infrared spectroscopy analysis was utilized to examine the effects on the resistive switching behaviors after 90 days under an atmospheric environment according to the chelation effect of the STN thin films. The devices were fabricated on a flexible plastic substrate, and they exhibited excellent durability upon repeated bending tests. They demonstrated good potential application for flexible and low-cost memory devices.
Auteurs: Ke-Jing Lee;Yu-Chi Chang;Cheng-Jung Lee;Li-Wen Wang;Dei-Wei Chou;Te-Kung Chiang;Yeong-Her Wang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2001 - 2007
Editeur: IEEE
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» Efficient Activity Detection in Untrimmed Video with Max-Subgraph Search
Résumé:
We propose an efficient approach for activity detection in video that unifies activity categorization with space-time localization. The main idea is to pose activity detection as a maximum-weight connected subgraph problem. Offline, we learn a binary classifier for an activity category using positive video exemplars that are “trimmed” in time to the activity of interest. Then, given a novel untrimmed video sequence, we decompose it into a 3D array of space-time nodes, which are weighted based on the extent to which their component features support the learned activity model. To perform detection, we then directly localize instances of the activity by solving for the maximum-weight connected subgraph in the test video's space-time graph. We show that this detection strategy permits an efficient branch-and-cut solution for the best-scoring-and possibly non-cubically shaped-portion of the video for a given activity classifier. The upshot is a fast method that can search a broader space of space-time region candidates than was previously practical, which we find often leads to more accurate detection. We demonstrate the proposed algorithm on four datasets, and we show its speed and accuracy advantages over multiple existing search strategies.
Auteurs: Chao Yeh Chen;Kristen Grauman;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 05.-2017, volume: 39, issue:5, pages: 908 - 921
Editeur: IEEE
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» Efficient Algorithms for the Identification of Top-$k$ Structural Hole Spanners in Large Social Networks
Résumé:
Recent studies show that individuals in a social network can be divided into different groups of densely connected communities, and these individuals who bridge different communities, referred to as structural hole spanners, have great potential to acquire resources/information from communities and thus benefit from the access. Structural hole spanners are crucial in many real applications such as community detections, diffusion controls, viral marketing, etc. In spite of their importance, little attention has been paid to them. Particularly, how to accurately characterize the structural hole spanners and how to devise efficient yet scalable algorithms to find them in a large social network are fundamental issues. In this paper, we study the top-k structural hole spanner problem. We first provide a novel model to measure the quality of structural hole spanners through exploiting the structural hole spanner properties. Due to its NP-hardness, we then devise two efficient yet scalable algorithms, by developing innovative filtering techniques that can filter out unlikely solutions as quickly as possible, while the proposed techniques are built up on fast estimations of the upper and lower bounds on the cost of an optimal solution and make use of articulation points in real social networks. We finally conduct extensive experiments to validate the effectiveness of the proposed model, and to evaluate the performance of the proposed algorithms using real world datasets. The experimental results demonstrate that the proposed model can capture the characteristics of structural hole spanners accurately, and the structural hole spanners found by the proposed algorithms are much better than those by existing algorithms in all considered social networks, while the running times of the proposed algorithms are very fast.
Auteurs: Wenzheng Xu;Mojtaba Rezvani;Weifa Liang;Jeffrey Xu Yu;Chengfei Liu;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 05.-2017, volume: 29, issue:5, pages: 1017 - 1030
Editeur: IEEE
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» Efficient and Confidentiality-Preserving Content-Based Publish/Subscribe with Prefiltering
Résumé:
Content-based publish/subscribe provides a loosely-coupled and expressive form of communication for large-scale distributed systems. Confidentiality is a major challenge for publish/subscribe middleware deployed over multiple administrative domains. Encrypted matching allows confidentiality-preserving content-based filtering but has high performance overheads. It may also prevent the use of classical optimizations based on subscriptions containment. We propose a support mechanism that reduces the cost of encrypted matching, in the form of a prefiltering operator using Bloom filters and simple randomization techniques. This operator greatly reduces the amount of encrypted subscriptions that must be matched against incoming encrypted publications. It leverages subscription containment information when available, but also ensures that containment confidentiality is preserved otherwise. We propose containment obfuscation techniques and provide a rigorous security analysis of the information leaked by Bloom filters in this case. We conduct a thorough experimental evaluation of prefiltering under a large variety of workloads. Our results indicate that prefiltering is successful at reducing the space of subscriptions to be tested in all cases. We show that while there is a tradeoff between prefiltering efficiency and information leakage when using containment obfuscation, it is practically possible to obtain good prefiltering performance while securing the technique against potential leakages.
Auteurs: Raphaël Barazzutti;Pascal Felber;Hugues Mercier;Emanuel Onica;Etienne Rivière;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 05.-2017, volume: 14, issue:3, pages: 308 - 325
Editeur: IEEE
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» Efficient Complex Root Tracing Algorithm for Propagation and Radiation Problems
Résumé:
An efficient complex root tracing algorithm for propagation and radiation problems is presented. The proposed approach is based on a discretization of Cauchy’s Argument Principle and its generalization to the $mathbb {C}times mathbb {R}$ space. Moreover, an engagement of the tracing process with a global root finding algorithm recently presented in the literature is performed. In order to confirm a validity and efficiency of the proposed technique, a few different types of structures have been analyzed.
Auteurs: Piotr Kowalczyk;Wojciech Marynowski;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2540 - 2546
Editeur: IEEE
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» Efficient Digital Quadrature Transmitter Based on IQ Cell Sharing
Résumé:
In this paper, we proposed and designed a digitally configured versatile RF quadrature transmitter. The transmitter efficiency was enhanced by IQ cell sharing and the deactivation of cells of opposite phases. In simulation, these techniques were able to increase the average efficiency of the transmitter from 46.3% to 70.7% for a 6.9-dB PAPR LTE signal. Moreover, the number of power amplifying cells was halved, improving the total efficiency of the transmitter. The proposed transmitter was implemented in a 6-b configuration at 0.8 GHz using a 28-nm CMOS process. Furthermore, the performance of the transmitter was verified. The dynamic range of the measured output power was in the range −20.2 to 13.9 dBm, and the measured average output power was 6.97 dBm for the 6.9-dB PAPR LTE signal. The measured power-added efficiencies of the transmitter at the peak power and average power were 40.43% and 29.1%, respectively.
Auteurs: Hadong Jin;Dongsu Kim;Bumman Kim;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 05.-2017, volume: 52, issue:5, pages: 1345 - 1357
Editeur: IEEE
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» Efficient Gas Sensor Devices Based on Surface Engineered Oxygen Vacancy Controlled TiO2 Nanosheets
Résumé:
Systematic optimization of the surface attributes (structural and morphological) as well as the defect states [oxygen vacancies (OVs)], for achieving efficient alcohol sensing by TiO2 nanosheets, is the central focus of this paper. Variation in the surface roughness and the OVs of hydrothermally grown TiO2 nanosheets were achieved by varying the ethanol and water content in stepwise manner, keeping the NaOH concentrations in the electrolyte unchanged. Structural, morphological, and optical characterizations, such as field emission scanning electronmicroscopy and X-ray photoelectronspectroscopy, revealed that with increase in ethanol concentrations, surface roughness increased (at a particular water concentration), while at a fixed ethanol concentration, OVs increased with decrease in water concentrations. The sensor derived through the minimum water content and the maximum ethanol content offered the most promising sensor response owing to availability of the maximum amount of OVs with the highest surface roughness.
Auteurs: Basanta Bhowmik;Partha Bhattacharyya;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2357 - 2363
Editeur: IEEE
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» Efficient Implementation for the AH FDTD Method With Iterative Procedure and CFS-PML
Résumé:
An efficient implementation for the associated Hermite finite-difference time-domain (AH FDTD) method with iterative procedure is proposed, which is an extension of previous works: the original and the paralleling-in-order-based AH FDTD methods. By introducing the alternating direction implicit method, the direct calculation of five-point matrix equation is replaced with iterative solving of tridiagonal matrices equations. For the 2-D case, only two tridiagonal matrixes need to be calculated in a full iterative cycle. In addition, the complex frequency shifted (CFS) perfectly matched layer (PML) is extended to the AH FDTD method and implemented together with this efficient solution scheme. Numerical examples show the superior computational performance of the proposed iterative procedure by comparison with the conventional FDTD method, the ADI FDTD method, and previous AH FDTD methods. The effectiveness of CFS-PML in AH FDTD is also verified.
Auteurs: Zheng-Yu Huang;Li-Hua Shi;Bin Chen;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2728 - 2733
Editeur: IEEE
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» Efficient Privacy-Preserving Facial Expression Classification
Résumé:
This paper proposes an efficient algorithm to perform privacy-preserving (PP) facial expression classification (FEC) in the client-server model. The server holds a database and offers the classification service to the clients. The client uses the service to classify the facial expression (FaE) of subject. It should be noted that the client and server are mutually untrusted parties and they want to perform the classification without revealing their inputs to each other. In contrast to the existing works, which rely on computationally expensive cryptographic operations, this paper proposes a lightweight algorithm based on the randomization technique. The proposed algorithm is validated using the widely used JAFFE and MUG FaE databases. Experimental results demonstrate that the proposed algorithm does not degrade the performance compared to existing works. However, it preserves the privacy of inputs while improving the computational complexity by $120$ times and communication complexity by $31$ percent against the existing homomorphic cryptography based approach.
Auteurs: Yogachandran Rahulamathavan;Muttukrishnan Rajarajan;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 05.-2017, volume: 14, issue:3, pages: 326 - 338
Editeur: IEEE
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» Efficient Processing of Skyline Queries Using MapReduce
Résumé:
The skyline operator has attracted considerable attention recently due to its broad applications. However, computing a skyline is challenging today since we have to deal with big data. For data-intensive applications, the MapReduce framework has been widely used recently. In this paper, we propose the efficient parallel algorithm SKY-MR+ for processing skyline queries using MapReduce. We first build a quadtree-based histogram for space partitioning by deciding whether to split each leaf node judiciously based on the benefit of splitting in terms of the estimated execution time. In addition, we apply the dominance power filtering method to effectively prune non-skyline points in advance. We next partition data based on the regions divided by the quadtree and compute candidate skyline points for each partition using MapReduce. Finally, we check whether each skyline candidate point is actually a skyline point in every partition using MapReduce. We also develop the workload balancing methods to make the estimated execution times of all available machines to be similar. We did experiments to compare SKY-MR+ with the state-of-the-art algorithms using MapReduce and confirmed the effectiveness as well as the scalability of SKY-MR+.
Auteurs: Yoonjae Park;Jun-Ki Min;Kyuseok Shim;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 05.-2017, volume: 29, issue:5, pages: 1031 - 1044
Editeur: IEEE
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» Efficient Resource Constrained Scheduling Using Parallel Two-Phase Branch-and-Bound Heuristics
Résumé:
Branch-and-bound (B&B) approaches are widely investigated in resource constrained scheduling (RCS). However, due to the lack of approaches that can generate a tight schedule at the beginning of the search, B&B approaches usually start with a large initial search space, which makes the following search of an optimal schedule time-consuming. To address this problem, this paper proposes a parallel two-phase B&B approach that can drastically reduce the overall RCS time. This paper makes three major contributions: i) it proposes three partial-search heuristics that can quickly find a tight schedule to compact the initial search space; ii) it presents a two-phase search framework that supports the efficient parallel search of an optimal schedule; iii) it investigates various bound sharing and speculation techniques among collaborative tasks to further improve the parallel search performance at different search phases. The experimental results based on well-established benchmarks demonstrate the efficacy of our proposed approach.
Auteurs: Mingsong Chen;Yongxiang Bao;Xin Fu;Geguang Pu;Tongquan Wei;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1299 - 1314
Editeur: IEEE
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» Efficient Scalable Parallel Higher Order Direct MoM-SIE Method With Hierarchically Semiseparable Structures for 3-D Scattering
Résumé:
A novel fast scalable parallel algorithm is proposed for the solution of large 3-D scattering problems based on: 1) the double (geometrical and current-approximation) higher order (DHO) method of moments (MoM) in the surface integral equation (SIE) formulation and 2) a direct solver for dense linear systems utilizing hierarchically semiseparable (HSS) structures. Namely, an HSS matrix representation is used for compression, factorization, and solution of the system matrix. In addition, a rank-revealing QR decomposition for memory compression is used, with a stopping criterion in terms of the relative rank tolerance value. A method for geometrical preprocessing of the scatterers based on the cobblestone distance sorting technique is employed in order to enhance the HSS algorithm accuracy and parallelization. Numerical examples show how the accuracy of the DHO HSS-MoM-SIE method is easily controllable by using the relative tolerance for the matrix compression. Moreover, the examples demonstrate low memory consumption, as well as much faster simulation time, when compared to the direct LU decomposition. The method enables dramatically faster monostatic scattering computations than iterative solvers and reduced number of unknowns when compared to low-order discretizations. Finally, great scalability of the algorithm is demonstrated on more than one thousand processes.
Auteurs: Ana B. Manić;Aaron P. Smull;François-Henry Rouet;Xiaoye Sherry Li;Branislav M. Notaroš;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2467 - 2478
Editeur: IEEE
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» Efficient Surgical Cutting with Position-Based Dynamics
Résumé:
Simulations of cuts on deformable bodies have been an active research subject for more than two decades. However, previous works based on finite element methods and mass spring meshes cannot scale to complex surgical scenarios. This article presents a novel method that uses position-based dynamics (PBD) for mesh-free cutting simulation. The proposed solutions include a method to efficiently render force feedback while cutting, an efficient heat diffusion model to simulate electrocautery, and a novel adaptive skinning scheme based on oriented particles.https://extras.computer.org/extra/mcg2017030024s1.mp4
Auteurs: Iago Berndt;Rafael Torchelsen;Anderson Maciel;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 24 - 31
Editeur: IEEE
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» Elastic Functional Coding of Riemannian Trajectories
Résumé:
Visual observations of dynamic phenomena, such as human actions, are often represented as sequences of smoothly-varying features. In cases where the feature spaces can be structured as Riemannian manifolds, the corresponding representations become trajectories on manifolds. Analysis of these trajectories is challenging due to non-linearity of underlying spaces and high-dimensionality of trajectories. In vision problems, given the nature of physical systems involved, these phenomena are better characterized on a low-dimensional manifold compared to the space of Riemannian trajectories. For instance, if one does not impose physical constraints of the human body, in data involving human action analysis, the resulting representation space will have highly redundant features. Learning an effective, low-dimensional embedding for action representations will have a huge impact in the areas of search and retrieval, visualization, learning, and recognition. Traditional manifold learning addresses this problem for static points in the euclidean space, but its extension to Riemannian trajectories is non-trivial and remains unexplored. The difficulty lies in inherent non-linearity of the domain and temporal variability of actions that can distort any traditional metric between trajectories. To overcome these issues, we use the framework based on transported square-root velocity fields (TSRVF); this framework has several desirable properties, including a rate-invariant metric and vector space representations. We propose to learn an embedding such that each action trajectory is mapped to a single point in a low-dimensional euclidean space, and the trajectories that differ only in temporal rates map to the same point. We utilize the TSRVF representation, and accompanying statistical summaries of Riemannian trajectories, to extend existing coding methods such as PCA, KSVD and Label Consistent KSVD to Riemannian trajectories or more generally to Riemannian functions. We - how that such coding efficiently captures trajectories in applications such as action recognition, stroke rehabilitation, visual speech recognition, clustering and diverse sequence sampling. Using this framework, we obtain state-of-the-art recognition results, while reducing the dimensionality/ complexity by a factor of 100-250x. Since these mappings and codes are invertible, they can also be used to interactively-visualize Riemannian trajectories and synthesize actions.
Auteurs: Rushil Anirudh;Pavan Turaga;Jingyong Su;Anuj Srivastava;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 05.-2017, volume: 39, issue:5, pages: 922 - 936
Editeur: IEEE
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» Electrical and Interfacial Properties of GaAs MOS Capacitors With La-Doped ZrON as Interfacial Passivation Layer
Résumé:
GaAs MOS capacitors with ZrTiON high- ${k}$ gate dielectric and ZrLaON or ZrON as interfacial passivation layer (IPL) are fabricated, and their electrical properties are investigated. As compared with a control sample without IPL, improved interfacial quality and electrical properties are obtained for both samples, with the ZrTiON/ZrLaON/GaAs device, exhibiting the lowest interface-state density ( $1.1 times 10^{12}$ cm $^{-2}$ eV $^{-1})$ , smallest gate leakage current density ( $1.62 times 10^{-5}$ A cm $^{-2}$ at $V_{g} =V_{{text {fb}}} + 1$ V), and largest equivalent dielectric constant (25.1). All of these should be attributed to the fact that incorporating La into the ZrON IPL can: first, passivate its defects and, second, enhance the blocking role of the IPL against the Ti/O in-diffusion to the GaAs substrate and the Ga/As out-diffusion to the high- ${k}$ , thus resulting in an obvious reduction of relevant defects in the gate stack and also suppressing the formation of unstable Ga/As oxides and As–As dimer at the GaAs surface to obtain a much improved dielectric/GaAs interface.
Auteurs: Han-Han Lu;Jing-Ping Xu;Lu Liu;Pui-To Lai;Wing-Man Tang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2179 - 2184
Editeur: IEEE
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» Electromagnetic Energy Harvesting Using Full-Wave Rectification
Résumé:
This paper presents a new approach to realizing full-wave rectification for electromagnetic energy harvesting. Instead of using one antenna to feed one rectifier circuit, we propose utilizing two antennas connected to one rectifier to form a full-wave rectenna. This balanced configuration allows the received power to be rectified and transferred to a dc load between two antennas, making it very easy to channel the harvested power in rectenna arrays. The proposed concept is demonstrated in the microwave regime using an array of full-wave rectennas optimized for 2.45 GHz. The full-wave rectenna array is compared with an array of half-wave rectennas that occupy the same footprint and are optimized to maximize power absorption at the same frequency. Measurements showed that the proposed full-wave rectifier performed better than the half-wave rectifier and achieved 74% radiation-to-dc conversion efficiency. Here, without loss of generality, the proposed concept is demonstrated using T-matched dipole antennas at a specific frequency, but the concept can be applied to other antenna types and other frequencies.
Auteurs: Faruk Erkmen;Thamer S. Almoneef;Omar M. Ramahi;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1843 - 1851
Editeur: IEEE
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» Electromagnetic Fields Generated Above a Shallow Sea by a Submerged Horizontal Electric Dipole
Résumé:
Great attention has been paid to the propagation of electromagnetic (EM) waves across the sea surface due to its important applications. Most of the previous research, however, focus on the half-space model illustrating the deep sea environment. In this communication, by taking into account the presence of a seafloor, the EM fields generated above shallow sea by a submerged horizontal electric dipole have been investigated theoretically and experimentally with a three-layer model. A set of formulas for EM fields in air expressed by Sommerfeld integrals are derived with recursive propagation approach, and the fields are computed using a complementary numerical integration technique. The effects of frequency, sea depth, seafloor conductivity, and receiver height on the fields are discussed. An experiment was conducted on shallow sea, and the test results agree well with theoretical predication in the quasi-near range. A transmission distance over 3 km above the sea surface was realized with reasonable transmitting power, which shows the potential of our theoretical model for applications in shallow sea environment.
Auteurs: Jinhong Wang;Bin Li;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2707 - 2712
Editeur: IEEE
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» Electromagnetic Performance Analysis of Graded Dielectric Inhomogeneous Streamlined Airborne Radome
Résumé:
Streamlined nosecone radomes for airborne applications have to cater to high-end electromagnetic (EM) performance requirements of fire control radar antenna system. In this regard, the EM performance analysis of an ogival radome based on novel graded dielectric inhomogeneous wall structure is presented. The radome wall considered here consists of seven dielectric layers cascaded in such a way that the middle layer has maximum dielectric parameters (dielectric constant and electric loss tangent) and on either side, dielectric parameters of the layers decrease in a graded (or stepwise) manner. Further, the outer surface of the radome wall is coated with an antistatic and antierosion radome paint. The EM performance parameters of the radome enclosing an X-band slotted waveguide planar array antenna (center frequency: 10 GHz; bandwidth: 1 GHz) are computed based on 3-D ray tracing in conjunction with aperture integration method. The study shows that the proposed graded dielectric inhomogeneous streamlined radome is an excellent choice for airborne applications as compared to airborne radomes based on conventional constant thickness radome designs and variable thickness radome (VTR) designs. Further, it circumvents the constraints on fabrication that occur in streamlined VTR designs.
Auteurs: P. S. Mohammed Yazeen;C. V. Vinisha;S. Vandana;M. Suprava;Raveendranath U. Nair;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2718 - 2723
Editeur: IEEE
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» Electronic license plates for drones [Spectral Lines]
Résumé:
In late 2015, mandatory drone registration went into effect in the United States. Since then, anyone who wants to fly a drone (or model aircraft) weighing over 0.55 pound (0.25 kilogram) must register with the U.S. Federal Aviation Administration to receive a unique identification number. This number needs to be placed on the drone, but there is no requirement for the tiny aircraft to broadcast signals to allow for remote identification. That might change in the future.
Auteurs: David Schneider;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 8 - 8
Editeur: IEEE
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» Embedded-Silicon-Strip-to-Hybrid-Plasmonic Waveguide Polarization Mode Converter
Résumé:
A novel polarization mode converter bridging a conventional embedded silicon strip waveguide and a metal-capped hybrid plasmonic waveguide is proposed. Innovative design principles based on gradient ascent of the TM polarization fraction in conjunction with the modal index contour for practical initial designs are developed and numerically verified. The mode conversion efficiency (MCE), insertion loss (IL), and the polarization conversion efficiency (PCE) at $lambda _{0}=1550$ nm are 87.58%, 0.5899 dB, and 99.84%, respectively. The respective 1-dB optical bandwidths for the MCE and IL are about 133 and 140 nm, while the PCE is > 98% over a 102-nm spectral range. The low-index silica spacer is found to impose the most stringent fabrication requirement.
Auteurs: Yin-Jung Chang;Ren-Wei Feng;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 759 - 762
Editeur: IEEE
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» Embedding Spatio-Temporal Information into Maps by Route-Zooming
Résumé:
Analysis and exploration of spatio-temporal data such as traffic flow and vehicle trajectories have become important in urban planning and management. In this paper, we present a novel visualization technique called route-zooming that can embed spatio-temporal information into a map seamlessly for occlusion-free visualization of both spatial and temporal data. The proposed technique can broaden a selected route in a map by deforming the overall road network. We formulate the problem of route-zooming as a nonlinear least squares optimization problem by defining an energy function that ensures the route is broadened successfully on demand while the distortion caused to the road network is minimized. The spatio-temporal information can then be embedded into the route to reveal both spatial and temporal patterns without occluding the spatial context information. The route-zooming technique is applied in two instantiations including an interactive metro map for city tourism and illustrative maps to highlight information on the broadened roads to prove its applicability. We demonstrate the usability of our spatio-temporal visualization approach with case studies on real traffic flow data. We also study various design choices in our method, including the encoding of the time direction and choices of temporal display, and conduct a comprehensive user study to validate our embedded visualization design.
Auteurs: Guodao Sun;Ronghua Liang;Huamin Qu;Yingcai Wu;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1506 - 1519
Editeur: IEEE
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» Emerging 3-D Imaging and Display Technologies
Résumé:
We have become an information-centric society vastly dependent on the collection, communication, and presentation of information. At any given moment, it is likely that we are in the vicinity of some form of a display as displays play a prominent role in a variety of devices and applications. Three-dimensional imaging and display technologies are important components for presentation and visualization of information and for creating real-world-like environments in communication. There are broad applications of 3-D imaging and display technologies in computers, communication, mobile devices, TV, video, entertainment, robotics, metrology, security and defense, healthcare, and medicine.
Auteurs: Bahram Javidi;A. Murat Tekalp;
Apparue dans: Proceedings of the IEEE
Date publication: 05.-2017, volume: 105, issue:5, pages: 786 - 788
Editeur: IEEE
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» Emerging Embedded and Cyber Physical System Security Challenges and Innovations
Résumé:
Auteurs: Kim-Kwang Raymond Choo;Mehran Mozaffari Kermani;Reza Azarderakhsh;Manimaran Govindarasu;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 05.-2017, volume: 14, issue:3, pages: 235 - 236
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Empirical Analysis of the Use of the VISIR Remote Lab in Teaching Analog Electronics
Résumé:
Remote laboratories give students the opportunity of experimenting in STEM by using the Internet to control and measure an experimental setting. Remote laboratories are increasingly used in the classroom to complement, or substitute for, hands-on laboratories, so it is important to know its learning value. While many authors approach this question through qualitative analyses, this paper reports a replicated quantitative study that evaluates the teaching performance of one of these resources, the virtual instrument systems in reality (VISIR) remote laboratory. VISIR, described here, is the most popular remote laboratory for basic analog electronics. This paper hypothesizes that use of a remote laboratory has a positive effect on students’ learning process. This report analyzes the effect of the use of VISIR in five different groups of students from two different academic years (2013–2014 and 2014–2015), with three teachers and at two educational levels. The empirical experience focuses on Ohm’s Law. The results obtained are reported using a pretest and post-test design. The tests were carefully designed and analyzed, and their reliability and validity were assessed. The analysis of knowledge test question results shows that the post-test scores are higher that the pretest. The difference is significant according to Wilcoxon test ( ${p} <0.001$ ), and produces a Cohen effect size of 1.0. The VISIR remote laboratory’s positive effect on students’ learning processes indicates that remote laboratories can produce a positive effect in students’ learning if an appropriate activity is used.
Auteurs: Javier Garcia-Zubia;Jordi Cuadros;Susana Romero;Unai Hernandez-Jayo;Pablo Orduña;Mariluz Guenaga;Lucinio Gonzalez-Sabate;Ingvar Gustavsson;
Apparue dans: IEEE Transactions on Education
Date publication: 05.-2017, volume: 60, issue:2, pages: 149 - 156
Editeur: IEEE
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» Enabling Backoff for SCM Wake-Up Radio: Protocol and Modeling
Résumé:
In sub-carrier modulation (SCM) wake-up radio (WuR) enabled wireless sensor networks, a node can initiate data transmission at any instant of time. In this letter, we propose to activate a backoff procedure before sending wake-up calls (WuCs) in order to avoid potential collisions among WuCs. Consequently, no backoff is needed for the main radio after a WuC is received. A discrete-time Markov chain model is developed to evaluate the performance. Numerical results on network throughput, energy efficiency, average delay, and collision probability reveal the benefits of enabling backoff for SCM-WuRs, especially under heavy traffic loads or saturated traffic conditions.
Auteurs: Debasish Ghose;Frank Y. Li;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1031 - 1034
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Enabling Focus Cues in Head-Mounted Displays
Résumé:
Developing head-mounted displays (HMDs) that offer uncompromised optical pathways to both digital and physical worlds without encumbrance and discomfort confronts many grand challenges, both from technological perspectives and human factors. Among the many challenges, minimizing visual discomfort is one of the key obstacles. One of the key contributing factors to visual discomfort is the lack of the ability to render proper focus cues in HMDs to stimulate natural eye accommodation responses, which leads to the wellknown problem of vergence–accommodation conflict. This paper provides a comprehensive summary of various technical approaches toward enabling focus cues in HMDs for both virtual reality (VR) and augmented reality (AR) applications.
Auteurs: Hong Hua;
Apparue dans: Proceedings of the IEEE
Date publication: 05.-2017, volume: 105, issue:5, pages: 805 - 824
Editeur: IEEE
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» Enabling the Extraction of Climate-Scale Temporal Salinity Variations from Aquarius: An Instrument Based Long-Term Radiometer Drift Correction
Résumé:
All channels of the Aquarius radiometer were observed to have calibration instability consisting of a drift in the antenna temperature during the first couple of months of the mission and pseudo-periodic oscillations of the antenna temperature over the mission life. For the version 4 Aquarius processing, both of these anomalies were corrected by removing a time variable bias in the Aquarius measurements relative to a seven-day global average from a salinity model. In order to accurately track long-term variation of salinity on climate scales it is necessary to decouple Aquarius radiometric calibration from ocean salinity models. In this paper, a new technique is used to investigate the nature of anomalies using nonocean vicarious external sources such as Antarctic ice or Amazonian rain forests. Two completely different solutions are developed to correct the pseudo-periodic oscillations as well as the drift of the Aquarius radiometers, decoupling the Aquarius measurements from salinity model.
Auteurs: Sidharth Misra;Shannon T. Brown;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2913 - 2923
Editeur: IEEE
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» Energizing 5G: Near- and Far-Field Wireless Energy and Data Trantransfer as an Enabling Technology for the 5G IoT
Résumé:
We are surrounded in our daily lives by a multitude of small, relatively inexpensive computing devices, many equipped with communication and sensing features. From these has evolved the concept of "pervasive intelligence" [1], [2], a basis from we can envision our future world as an Internet of Things/Internet of Everything (IoT/IoE), in terms of both a consumer IoT/IoE (interconnected devices within an individual's environment) and the Industrial IoT (interconnectedness to improve business-to-business services, mainly through machineto-machine interactions) [3].
Auteurs: Alessandra Costanzo;Diego Masotti;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 125 - 136
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Energy and Spectral Efficiency of Cellular Networks With Discontinuous Transmission
Résumé:
Cell discontinuous transmission (DTX) has been proposed as a solution to reduce the energy consumption of cellular networks. This paper investigates the impact of network traffic load on the spectral and energy efficiency of cellular networks with DTX. The signal-to-interference-plus-noise ratio (SINR) distribution as a function of traffic load is derived first. Then, the sufficient condition for ignoring thermal noise and simplifying the SINR distribution is investigated. Based on the simplified SINR distribution, the network spectral and energy efficiency as functions of network traffic load are derived. It is shown that the network spectral efficiency increases monotonically in traffic load, while the optimal network energy efficiency depends on the ratio of the sleep-mode power consumption to the active-mode power consumption of base stations. If the ratio is larger than a certain threshold, the network energy efficiency increases monotonically with network traffic load and is maximized when the network is fully loaded. Otherwise, the network energy efficiency first increases and then decreases in network traffic load. The optimal load can be identified with a binary search algorithm. The power ratio threshold depends solely on the path loss exponent $alpha$ , e.g., 56% for $alpha = 4$ . All these analytic results are further validated by the numerical simulations.
Auteurs: Peiliang Chang;Guowang Miao;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2991 - 3002
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Energy Based Limit Cycle Control of Elastically Actuated Robots
Résumé:
A new control law for elastic joint robots that allows to regulate an energy function of the system to a desired value is presented in this technical note. Being able to either remove energy from the system or inject into it, oscillations can be both damped out and induced. The proposed nonlinear dynamic state feedback controller forces the system to evolve on a submanifold of the configuration space. The reduced dynamics of the system and of the controller itself are similar to a single elastic joint, for which an asymptotically stable limit cycle is obtained regulating an energy function to a positive desired value. When the desired value of the energy function is chosen to be zero, then the asymptotically stable limit cycle reduces to an asymptotically stable equilibrium point. In this case the oscillations are damped out and the desired task-space configuration is reached. The design of the controller extensively uses the concept of conditional stability, so that the limit cycle can be designed for a lower dimensional dynamical system, although it will result to be a limit cycle for the whole system.
Auteurs: Gianluca Garofalo;Christian Ott;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2490 - 2497
Editeur: IEEE
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» Energy Beamforming for Wireless Power Transfer in MISO Heterogeneous Network With Power Beacon
Résumé:
This letter considers an energy harvesting heterogeneous network (EHHN) in which a power beacon (PB) for radio-frequency-energy transfer coexists with a base station for information transfer. In this network, a tradeoff exists between harvested energy and information rate, because the energy transfer of the PB causes the interference to the information transfer. To determine the optimal energy-transfer strategy under this tradeoff, we propose an energy beamforming scheme that maximizes the weighted sum of the harvested energy and the information rate in multiple-input single-output EHHN. Because the weighted-sum-maximization problem is nonconvex, we partition it into a difference of convex functions problem and a convex-maximization problem, and then solve them using efficient convex-based algorithms. In simulation, the proposed beamforming scheme is shown to achieve a near-optimal rate-energy region for the considered problem.
Auteurs: Jong-Hyeok Park;Yo-Seb Jeon;Soohee Han;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1163 - 1166
Editeur: IEEE
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» Energy Efficiency for Clustered Heterogeneous Multicores
Résumé:
Heterogeneous multicore systems clustered in multiple Voltage Frequency Islands (VFIs) are the next-generation solution for power and energy efficient computing systems. Due to the heterogeneity, the power consumption and execution time of a task changes not only with Dynamic Voltage and Frequency Scaling (DVFS), but also according to the task-to-island assignment, presenting major challenges for power management and energy minimization techniques. This paper focuses on energy minimization of periodic real-time tasks (or performance-constrained tasks) on such systems, in which the cores in an island are homogeneous and share the same voltage and frequency, but different islands have different types and numbers of cores and can be executed at other voltages and frequencies. We present an efficient algorithm to minimize the total energy consumption while satisfying the timing constraints of all tasks. Our technique consists of the coordinated selection of the voltage and frequency levels for each island, together with a task partitioning strategy that considers the energy consumption of the task executing on different islands and at different frequencies, as well as the impact of the frequency and the underlying core architecture to the resulting execution time. Every task is then mapped to the most energy efficient island for the selected voltage and frequency levels, and to a core inside the island such that the workloads of the cores in a VFI are balanced. We experimentally evaluate our technique and compare it to state-of-the-art solutions, resulting in average in 25 percent less energy consumption (and up to 87 percent for some cases), while guaranteeing that all tasks meet their deadlines.
Auteurs: Santiago Pagani;Anuj Pathania;Muhammad Shafique;Jian-Jia Chen;Jörg Henkel;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1315 - 1330
Editeur: IEEE
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» Energy Efficiency Optimization in 3-D Small Cell Networks-Based Sleep Strategy
Résumé:
In this letter, we focus on energy efficiency in small cell networks where a large number of small cells are spatial deployed in dense urban area. We optimize the energy efficiency by sleep mechanism under average connection ratio (ACR) and average user rate constrains. First, we derive the average rate in 3-D small cell networks by Matern Hardcore point process. Then, based on monotonicity analysis, the optimal small cell sleep probability is calculated to satisfy both ACR and average rate constrains. In addition, we also formulate an optimal maximum connection number of small cell that minimizes the energy consumption subject to the joint constraint of ACR and average rate. Numerical results show that with the sleep strategy, the small cell networks energy consumption can be reduce about 21% of the total. Our optimal sleep probability and maximum connection number can be effectively applied to design small cell sleep strategy for 3-D small cell networks.
Auteurs: Ziyu Pan;Qi Zhu;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1131 - 1134
Editeur: IEEE
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» Energy Harvesting Communication Using Finite-Capacity Batteries With Internal Resistance
Résumé:
Modern systems will increasingly rely on energy harvested from their environment. Such systems utilize batteries to smooth out the random fluctuations in harvested energy. These fluctuations induce highly variable battery charge and discharge rates, which affect the efficiencies of practical batteries that typically have non-zero internal resistance. In this paper, we study an energy harvesting communication system using a finite battery with non-zero internal resistance. We adopt a dual-path architecture, in which harvested energy can be directly used, or stored and then used. In a frame, both time and power can be split between energy storage and data transmission. For a single frame, we derive an analytical expression for the rate optimal time and power splitting ratios between harvesting energy and transmitting data. We then optimize the time and power splitting ratios for a group of frames, assuming non-causal knowledge of harvested power and fading channel gains, by giving an approximate solution. When only the statistics of the energy arrivals and channel gains are known, we derive a dynamic programming-based policy and propose three sub-optimal policies, which are shown to perform competitively. In summary, this paper suggests that battery internal resistance significantly impacts the design and performance of energy harvesting communication systems and must be considered.
Auteurs: Rajshekhar Vishweshwar Bhat;Mehul Motani;Teng Joon Lim;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2822 - 2834
Editeur: IEEE
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» Energy-Efficient Management of Cognitive Radio Terminals With Quality-Based Activation
Résumé:
In cooperative cognitive radio systems (CRSs), where battery-powered cognitive radio terminals (CTs) frequently sense and report primary user’s (PU’s) existence to exploit a spectrum hole, energy efficiency (EE) is a challenging design issue. To improve EE in CRSs, letting only some of the CTs be active in sensing and reporting [called a quality-based activation (QBA)] is proposed in this letter. With QBA, CTs that have good channel quality in a data channel (DCH) as well as a reporting channel (RCH) are allowed to sense and report. A possible drawback of such conditional activation is that it could limit the participation of CTs in a scheduling procedure, and hence, may result in losing certain system throughput. Throughput and EE of CRSs with the proposed QBA are investigated and it is shown, with numerical examples, that QBA does not decrease the throughput and provides significant improvement in EE.
Auteurs: Junaid Imtiaz;Dongwoo Kim;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1171 - 1174
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Engineering Outreach: Yesterday, Today, and Tomorrow [SP Education]
Résumé:
This article discusses the current landscape of outreach efforts in the United States to engage K-12 students in engineering. It then provides an overview of two programs run by the College of Engineering and Applied Sciences, and the Institute for Science, Technology, Engineering, and Mathematics Education at Stony Brook University (SBU) to promote student participation and interest in engineering. These efforts are aligned with the recently released Next Generation Science Standards (NGSS), which emphasize incorporating engineering design principles in K-12 science education. We describe two models, one in the form of an on-campus summer camp and the other as a series of after-school activities with both on-and off-campus offerings. These experiences are rarely available in K-12 schools and have the added benefit of exposing students to engineering faculty and researchers. The programs are focused on electrical and computer engineering with emphasis on signal and information processing and analysis and have hosted more than 200 students for the past six years.
Auteurs: Monica F. Bugallo;Angela M. Kelly;
Apparue dans: IEEE Signal Processing Magazine
Date publication: 05.-2017, volume: 34, issue:3, pages: 69 - 100
Editeur: IEEE
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» Enhanced Performance of Thiophene-Rich Heteroacene, Dibenzothiopheno [6,5-b:6’,5’-f] Thieno[3,2-b]Thiophene Thin-Film Transistor With MoOx Hole Injection Layers
Résumé:
In this letter, we demonstrated a high performance organic thin-film transistor using thermally evaporated amorphous phase MoOx as a hole injection layer between metal electrodes and organic semiconductor. The fabricated organic thin-film transistors showed the field-effect mobility of 7 cm $^{{2}}$ /Vs in linear and saturation regimes and an ON/OFF current ratio of $10^{{7}}$ . The MoOx hole injection layers significantly reduced the injection barrier from metal electrode, resulting in the improvement of ohmic contact properties of a synthesized thiophene-rich heteroacene, dibenzothiopheno [6,5-b:6’,5’-f] thieno [3,2-b] thiophene p-type organic semiconductor, as compared with those with single metals. Furthermore, high performance organic thin-film transistors can be successfully realized with Al electrode, which is not suitable for p-type organic semiconductors due to its low work function by introducing a 75-nm-thick MoOx hole injection layer.
Auteurs: Youngjun Yun;Ajeong Choi;Suk Gyu Hahm;Jong Won Chung;Yong Uk Lee;Ji Young Jung;Joo-Young Kim;Jeong-Il Park;Sangyoon Lee;Jaewon Jang;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 649 - 652
Editeur: IEEE
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» Enhanced Self-Sensing Capability of Permanent-Magnet Synchronous Machines: A Novel Saliency Modulation Rotor End Approach
Résumé:
This paper investigates a novel rotor configuration of a permanent-magnet synchronous machine (PMSM) in which a saliency modulation rotor end is added to the machine rotor to improve the self-sensing capability. The saliency-based self-sensing control method is widely adopted for position estimation at stand-still and low speed range. However, the performance is heavily affected by saturation effects for conventional PMSMs, because the machine saliency variates with increased fundamental stator flux under loaded operation. The proposed scheme provides an additional space anisotropic to the rotor. Saliency modulation of the rotor end is electrically asynchronous with the machine fundamental reference frame. Hence the tracked machine saliency provided by the rotor end is no longer affected by saturation effects. In addition, for medium and high speed ranges, the rotor end saliency can be modulated with the fundamental voltage and the rotor position can be tracked without superposed injection. A genetic algorithm optimization environment joined with finite element analysis allows obtaining optimized rotor end geometry for better position signal quality. The expected self-sensing performance is validated by experimental results.
Auteurs: Tianhao Wang;He Zhang;Qiang Gao;Zhuang Xu;Jing Li;Chris Gerada;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3548 - 3556
Editeur: IEEE
Document complet vers site de l'éditeur
 


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