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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 05-2017 trié par par titre, page: 4
» Disseminating the Best Material to Practitioners
Résumé:
As this department celebrates its second year, its editors restate its mission and scope of interest, invite appropriate articles, and look at some previous contributions.
Auteurs: Phillip Laplante;Steve Counsell;Giuliano Antoniol;
Apparue dans: IEEE Software
Date publication: 05.-2017, volume: 34, issue:3, pages: 111 - 113
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 Spectrum Management in TV White Space Networks
Résumé:
We investigate the distributed spectrum management problem in opportunistic TV white space (TVWS) systems using a game theoretical approach that accounts for adjacent-channel interference and spatial reuse. TV band devices (TVBDs) compete to access idle TV channels and select channel “blocks” that optimize an objective function. This function provides a tradeoff between the achieved rate and a cost factor that depends on the interference between TVBDs. We consider practical cases where contiguous or noncontiguous channels can be accessed by TVBDs, imposing realistic constraints on the maximum frequency span between the aggregated/bonded channels. We show that under general conditions, the proposed TVWS management games admit a potential function. Accordingly, a “best response” strategy allows us to determine the spectrum assignment of all players. This algorithm is shown to converge in a few iterations to a Nash equilibrium. Furthermore, we propose an effective algorithm based on Imitation dynamics, where a TVBD probabilistically imitates successful selection strategies of other TVBDs in order to improve its objective function. Numerical results show that our game theoretical framework provides a very effective tradeoff (close to optimal, centralized spectrum allocations) between efficient TV spectrum use and reduction of interference between TVBDs.
Auteurs: Jocelyne Elias;Fabio Martignon;Lin Chen;Marwan Krunz;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4161 - 4172
Editeur: IEEE
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» Distributed Teams, Developer Participation, and More
Résumé:
This instalment reports on two talks from the First International Workshop on Collaborative Modeling in MDE (model-driven engineering) and three papers from the 23rd International Conference on Software Analysis, Evolution, and Reengineering. The topics covered include model-driven engineering, forking and developer participation, FLOSS (free/libre and open source software) software projects, and perceptions of release practices.
Auteurs: Jeffrey C. Carver;Henry Muccini;Aiko Yamashita;
Apparue dans: IEEE Software
Date publication: 05.-2017, volume: 34, issue:3, pages: 114 - 116
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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» Do Not Capture: Automated Obscurity for Pervasive Imaging
Résumé:
The pervasive use of smartphones and wearables can compromise individuals' privacy, as they become unaware subjects of pictures and videos. Do Not Capture is a novel technology that removes unwilling subjects from media at capture time.
Auteurs: Moo-Ryong Ra;Seungjoon Lee;Emiliano Miluzzo;Eric Zavesky;
Apparue dans: IEEE Internet Computing
Date publication: 05.-2017, volume: 21, issue:3, pages: 82 - 87
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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» Downlink Transmission of Short Packets: Framing and Control Information Revisited
Résumé:
Cellular wireless systems rely on frame-based transmissions. The frame design is conventionally based on heuristics, consisting of a frame header and a data part. The frame header contains control information that provides pointers to the messages within the data part. In this paper, we revisit the principles of frame design and show the impact of the new design in scenarios that feature short data packets, which are central to various 5G and Internet of Things applications. We treat framing for downlink transmission in an AWGN broadcast channel with $K$ users, where the sizes of the messages to the users are random variables. Using approximations from finite blocklength information theory, we establish a framework in which a message to a given user is not necessarily encoded as a single packet, but may be grouped with messages to other users and benefit from the improved efficiency of longer codes. This requires changes in the way control information is sent, and it requires that the users need to spend power decoding other messages, thereby increasing the average power consumption. We show that the common heuristic design is only one point on a curve that represents the tradeoff between latency and power consumption.
Auteurs: Kasper Fløe Trillingsgaard;Petar Popovski;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 2048 - 2061
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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» Edge Position Detection of On-line Charged Vehicles With Segmental Wireless Power Supply
Résumé:
Online charged electrical vehicles (EVs) with segmental wireless power supply obtain energy from power tracks without a physical cable contact while traveling. When a vehicle moves from one segmental track to another, the power supply coils should switch accordingly to provide energy continually at various positions. As the secondary coil fixed in the vehicle moves along the primary coil mounted in the segmental track, the mutual inductance of these two coils changes accordingly, which results in the varying of the phase angle that the current lags the voltage in the resonant circuit at the primary side. The paper presents a method to decide the power switching time through detecting the changing of the phase angle. A higher phase angle varying range (PAVR) is preferred to achieve a better position judgment. Quality factors at the primary and secondary sides, as well as the mutual inductance between two sides for the higher PAVR, are analyzed. The phase angle change can be detected in the circuit at the primary side when an EV leaves the energized coil region. Besides that, a detecting signal is introduced to find the approaching of EVs for those de-energized coils. The system robustness and magnetic saturation are also analyzed. A scaled-down laboratory prototype is set up to test the proposed method. Within parameter drifts of ±4% of the rating inductance or capacitance, the prototype works perfectly under the rated operation frequency and switching threshold angle. Experiments show that the position detection method can detect not only the approaching but the leaving of vehicles as well.
Auteurs: Qijun Deng;Jiangtao Liu;Dariusz Czarkowski;Mariusz Bojarski;Jing Chen;Wenshan Hu;Hong Zhou;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 3610 - 3621
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 sharing of optical resources in low-power optical networks-on-chip
Résumé:
With the ever-growing core counts in modern computing systems, networks-on-chip (NoCs) consume an increasing part of the power budget due to bandwidth and power density limitations of electrical interconnects. To maintain performance and power scaling, alternative technologies are required, with silicon photonics being a promising candidate thanks to high-bandwidth, lowenergy data transmission. To get the best of silicon photonics, sophisticated network designs are required to minimize static power overheads. In this paper, we propose Amon, a low-power optical NoC that decreases the number of μRings, wavelengths, and path losses to reduce power consumption. Amon performs destination checking prior to data transmission on an underlying control network, allowing the sharing of optical bandwidth. Compared to a wide range of state-of-the-art optical, hybrid, and electrical NoCs, Amon improves throughput-per-watt by at least 23% (up to 70%), while reducing power without latency overheads on both synthetic and realistic applications. For aggressive optical technology parameters, Amon considerably outperforms all alternative NoCs in terms of power, highlighting its increasing superiority as technology matures.
Auteurs: Sebastian Werner;Javier Navaridas;Mikel Luján;
Apparue dans: IEEE/OSA Journal of Optical Communications and Networking
Date publication: 05.-2017, volume: 9, issue:5, pages: 364 - 374
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
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» 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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» Empirical Determination of the Effect of Lifter Wear in Mill Power for Dry Grinding
Résumé:
Grinding stage has one of the highest production costs in mining operations due to the intensive use of energy needed for the comminution process. Hence, any improvement in the energy use of this process will have an important impact on production costs. Paper presents the results of an extensive testing program to determine the effect of lifter wear on the power demanded by the grinding mill. Selected power–speed curves covering up to 110% of critical speed are reported. Using these results, a lifter wear factor is proposed to include this effect on the power demand expressions of grinding mills. Results show that for dry grinding, as the lifters wear, the power needed for a specific operating condition increases. Using these results, mill operators will have an important piece of information to set the best operating point for an efficient ore comminution and efficient energy consumption. It will also help to define the appropriate date for a liner change.
Auteurs: Richard A. Cartes Varas;M. Aníbal Valenzuela;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2621 - 2627
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
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» 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 Mobile and Wireless Technologies for Smart Cities: Part 3
Résumé:
The articles in this special section focuses on the deployment of mobile and wireless technologies and services in smart cities.
Auteurs: Ejaz Ahmed;Muhammad Imran;Mohsen Guizani;Ammar Rayes;Jaime Lloret;Guangjie Han;Wael Guibene;
Apparue dans: IEEE Communications Magazine
Date publication: 05.-2017, volume: 55, issue:5, pages: 24 - 25
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
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» 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
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» Energy and Spectral Efficiency Tradeoff for Massive MIMO Systems With Transmit Antenna Selection
Résumé:
This correspondence investigates the fundamental tradeoff between the spectral efficiency (SE) and energy efficiency (EE) for massive multiple-input multiple-output (MIMO) systems with linear precoding and transmit antenna selection, where both the circuit power consumption and the large-scale fading are considered. The EE and SE are optimized with respect to the number of transmit antennas and transmit power, and consequently, we formulate the EE–SE tradeoff as a mixed-integer-continuous-variable multiobjective optimization (MOO) problem. Using the derived EE–SE relations, the properties of the Pareto front for the EE–SE tradeoff are analyzed. To solve the complicated MOO problem, we develop two algorithms: the weighted-sum particle swarm optimization (WS-PSO) algorithm and the normal-boundary-intersection particle swarm optimization (NBI-PSO) algorithm. Simulation results show that the two algorithms can achieve the Pareto optimal EE-SE tradeoff, and NBI-PSO provides more evenly distributed solutions than WS-PSO.
Auteurs: Zujun Liu;Weimin Du;Dechun Sun;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4453 - 4457
Editeur: IEEE
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» 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 Challenges of 5G Small Cell Networks
Résumé:
The deployment of a large number of small cells poses new challenges to energy efficiency, which has often been ignored in 5G cellular networks. While massive MIMO will reduce the transmission power at the expense of higher computational cost, the question remains as to which (computation or transmission power) is more important in the energy efficiency of 5G small cell networks. Thus, the main objective in this article is to investigate the computation power based on the Landauer principle. Simulation results reveal that more than 50 percent of the energy is consumed by the computation power at 5G small cell BSs. Moreover, the computation power of a 5G small cell BS can approach 800 W when massive MIMO (e.g., 128 antennas) is deployed to transmit high volume traffic. This clearly indicates that computation power optimization can play a major role in the energy efficiency of small cell networks.
Auteurs: Xiaohu Ge;Jing Yang;Hamid Gharavi;Yang Sun;
Apparue dans: IEEE Communications Magazine
Date publication: 05.-2017, volume: 55, issue:5, pages: 184 - 191
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-Aware Dynamic Selection of Overlay and Underlay Spectrum Sharing for Cognitive Small Cells
Résumé:
Small cell (SC) base stations with cognitive capabilities are seen as an efficient way to cope with interference between the SC base stations and macrocell base stations (MBSs). Cognitive SCs may access the spectrum by means of overlay or underlay mode. An efficiency of the overlay mode fully depends on the activity of macrocell users (MUEs), since insufficient resources remain for small cell users (SUEs). Contrarily, the main weakness of the underlay mode is that it can result in low transmission efficiency due to restricted transmission power. Apart from the transmission efficiency of both modes, an energy consumption of the SCs should not be disregarded. Thus, we propose a centralized scheme selecting the spectrum sharing mode in the downlink, according to both the SUEs’ throughput and the energy consumption of the SCs. The objective is to maximize the overall performance of the SCs, while their energy consumption is taken into account. Then, we also propose a distributed algorithm in order to decrease complexity and signaling overhead of the centralized scheme. The results show that the proposed dynamic selection significantly outperforms all competitive schemes in terms of the SUEs’ throughput, while the throughput of MUEs is intact, and only negligible signaling overhead is generated in the case of the proposed distributed algorithm. Moreover, the proposed algorithm is able to notably decrease the energy consumption of the SCs.
Auteurs: Pavel Mach;Zdenek Becvar;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4120 - 4132
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
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» 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 Cellular Coverage and Throughput Using Rateless Codes
Résumé:
Rateless codes have been shown to provide robust error correction over a wide range of binary and noisy channels. Using a stochastic geometry model, this paper studies the performance of rateless codes in the cellular downlink and compares it with the performance of fixed-rate codes. For the case of Rayleigh fading, an accurate approximation is proposed for the distribution of the packet transmission time of $K$ -bit information packets using rateless codes. The two types of channel coding schemes are compared by evaluating the typical user and per-user success probability and the rate. Based on both the analytical results and simulations, the paper shows that rateless coding provides a significant throughput gain relative to fixed-rate coding. Moreover, the benefit is not restricted to the typical user but applies to all users in the cellular network.
Auteurs: Amogh Rajanna;Martin Haenggi;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 1899 - 1912
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
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» Enhancing Flatbed Printer Accuracy and Throughput: Optimal Rational Feedforward Controller Tuning Via Iterative Learning Control
Résumé:
Advanced control methods potentially enable performance improvements in printing systems for minor additional costs. The aim of this paper is to develop a control framework that is capable of delivering throughput and accuracy enhancements for an industrial flatbed inkjet printer. The proposed method involves iterative learning control with a rational feedforward parameterization to enable varying position references which are required for printing. Experimental results highlight the efficacy of the proposed method in a comparison with related pre-existing learning control approaches.
Auteurs: Joost Bolder;Jurgen van Zundert;Sjirk Koekebakker;Tom Oomen;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4207 - 4216
Editeur: IEEE
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» Enhancing Network Parameter Error Detection and Correction via Multiple Measurement Scans
Résumé:
Although the normalized Lagrange multiplier (NLM) method has been shown to be very effective for network parameter error identification, errors in parameters corresponding to insensitive NLMs still remain difficult to detect and correct. This paper proposes an enhanced method for detecting and correcting network parameter errors based on multiple measurement scans. The method is developed by first deriving the relationship between parameter errors and the associated Langrage multipliers in state estimation. This is then used to clarify the reason behind the sensitivity issue of NLMs and the improvements made by performing multiple scans. An approach for estimating the necessary number of scans for satisfying various detection requirements is also proposed. Moreover, a local parameter error correction procedure based on multiple scans is presented, with detailed discussion of the local network selection and the number of required measurement scans. Simulation results in a very large utility system in North America illustrate the effectiveness of the analysis and methods proposed in this paper.
Auteurs: Yuzhang Lin;Ali Abur;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2417 - 2425
Editeur: IEEE
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» Enhancing Power Transformer Differential Protection to Improve Security and Dependability
Résumé:
Current differential principle is a well-known principle used for protection of transformers, motors, generators, buses, and any other type of power equipment with input and output current measurements. Further, the principle is used in developing percent differential protection, which can be programmed to the desired sensitivity for detecting in-zone faults and security during external faults. This protection dependability is usually achieved by modeling a differential-restraining characteristic with two regions, operating and nonoperating, and tracking the real differential restraint ratio during faults. Some external faults with high dc offset and high X/R system time constant would easily saturate the installed current transformers (CTs), which in return would cause high differential/restraint ratio above the preset characteristic into the operating region. In such cases, the differential protection would operate and cause unwanted transformer trip. This paper focuses on some enhancements applied to the differential principle of the main differential protection; it also defines guidance on how to setup the protection for better sensitivity and security. The paper is supported by fault cases, showing the improved security and dependability during internal/external faults with and without CT saturation.
Auteurs: Lubomir Sevov;Umar Khan;Zhiying Zhang;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2642 - 2649
Editeur: IEEE
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» Enhancing the Gaming Experience Using 3D Spatial User Interface Technologies
Résumé:
Three-dimensional (3D) spatial user interface technologies have the potential to make games more immersive and engaging and thus provide a better user experience. Although technologies such as stereoscopic 3D display, head tracking, and gesture-based control are available for games, it is still unclear how their use affects gameplay and if there are any user performance benefits. The authors have conducted several experiments on these technologies in game environments to understand how they affect gameplay and how we can use them to optimize the gameplay experience.
Auteurs: Arun Kulshreshth;Kevin Pfeil;Joseph J. LaViola;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 16 - 23
Editeur: IEEE
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» Entanglement-Assisted Capacities of Compound Quantum Channels
Résumé:
We study universal quantum codes for entanglement-assisted quantum communication over compound quantum channels. In this setting, sender and receiver do not know the specific channel that will be used for communication, but only know the set that the channel is selected from. We investigate different variations of the problem: uninformed users, informed receiver, informed sender, and feedback assistance. We derive single-letter formulas for all corresponding channel capacities. Our proofs are based on one-shot decoupling bounds and properties of smooth entropies.
Auteurs: Mario Berta;Hrant Gharibyan;Michael Walter;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3306 - 3321
Editeur: IEEE
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» Epileptic Focus Localization Using Discrete Wavelet Transform Based on Interictal Intracranial EEG
Résumé:
Over the past decade, with the development of machine learning, discrete wavelet transform (DWT) has been widely used in computer-aided epileptic electroencephalography (EEG) signal analysis as a powerful time-frequency tool. But some important problems have not yet been benefitted from DWT, including epileptic focus localization, a key task in epilepsy diagnosis and treatment. Additionally, the parameters and settings for DWT are chosen empirically or arbitrarily in previous work. In this work, we propose a framework to use DWT and support vector machine (SVM) for epileptic focus localization problem based on EEG. To provide a guideline in selecting the best settings for DWT, we decompose the EEG segments in seven commonly used wavelet families to their maximum theoretical levels. The wavelet and its level of decomposition providing the highest accuracy in each wavelet family are then used in a grid search for obtaining the optimal frequency bands and wavelet coefficient features. Our approach achieves promising performance on two widely-recognized intrancranial EEG datasets that are also seizure-free, with an accuracy of 83.07% on the Bern-Barcelona dataset and an accuracy of 88.00% on the UBonn dataset. Compared with existing DWT-based approaches in epileptic EEG analysis, the proposed approach leads to more accurate and robust results. A guideline for DWT parameter setting is provided at the end of the paper.
Auteurs: Duo Chen;Suiren Wan;Forrest Sheng Bao;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 05.-2017, volume: 25, issue:5, pages: 413 - 425
Editeur: IEEE
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» Equipment Utilization Enhancement in Photolithography Area Through a Dynamic System Control Using Multi-Fidelity Simulation Optimization With Big Data Technique
Résumé:
Photolithographic (Photo) plays a key role in semiconductor manufacturing because of its importance to advanced process shrinking. Even with a small improvement in its operational efficiency, the cost competitiveness in production can be enhanced as a result of the huge amount of share capital cost. However, it is difficult to stabilize the throughput rhythm of Fabs, while keeping a high equipment utilization for Photo. In the light of Industry 4.0 and big data, a huge potential of maintaining a desired system performance by (near) real-time dynamic system control is highly anticipated. But it also poses challenges to intelligently handling mass data acquisition and allocating computing resources. This research aims to maximize the equipment utilization in Photo by an efficient multi-model simulation optimization approach with big data techniques in the era of Industry 4.0. dynamic Photo configurator and abnormality detector are the two critical units in our proposed system framework; the former can make a quick decision to optimize the system configuration while receiving the adjustment request from the latter. The results from an empirical study show the practical viability of proposed approach that the capacity loss in Photo has been effectively improved.
Auteurs: Liam Y. Hsieh;Edward Huang;Chun-Hung Chen;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 05.-2017, volume: 30, issue:2, pages: 166 - 175
Editeur: IEEE
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» Ergodic Spectral Efficiency in MIMO Cellular Networks
Résumé:
This paper shows how the application of stochastic geometry to the analysis of wireless networks is greatly facilitated by: ( ${i}$ ) a clear separation of time scales; (ii) the abstraction of small-scale effects via ergodicity; and (iii) an interference model that reflects the receiver’s lack of knowledge of how each individual interference term is faded. These procedures render the analysis both more manageable and more precise, as well as more amenable to the incorporation of subsequent features. In particular, the paper presents analytical characterizations of the ergodic spectral efficiency of cellular networks with single-user multiple-input multiple-output and sectorization. These characterizations, in the form of easy-to-evaluate expressions, encompass the coverage, the distribution of spectral efficiency over the network locations, and the average thereof.
Auteurs: Geordie George;Ratheesh K. Mungara;Angel Lozano;Martin Haenggi;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2835 - 2849
Editeur: IEEE
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» Erratum to “An Online UPS System That Eliminates the Inrush Current Phenomenon While Feeding Multiple Load Transformers”
Résumé:
Auteurs: Syed Sabir Hussain Bukhari;Thomas A. Lipo;Byung-Il Kwon;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2650 - 2650
Editeur: IEEE
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» Error-Resilient Integrated Clock Gate for Clock-Tree Power Optimization on a Wide Voltage IOT Processor
Résumé:
Energy-efficiency optimization occupies an important position in the Internet of Things application. The error-resilience technique has begun to emerge and brought the performance and energy benefits as a new vision for alternative computing, because it eliminates the overconstrained margin in current processor design flow and protects the system from process, supply voltage, temperature, and aging variations through an error-resilient mechanism rather than expensive guardbands. However, as a traditional clock-tree power optimization technique, the clock gating mechanism cannot work in such a system when it faces the timing violation problem. In this paper, we propose an error-resilient integrated clock gate (ERICG) and its automatic integration methodology in error detection and correction (EDAC) system design flow. ERICG can provide the ability of in situ timing EDAC with only four additional transistors compared with a conventional integrated clock gate. The SPICE simulation shows that it is a metastable-hardened cell and can work well in the wide voltage operation (0.5~ 1.1 V) including the near-threshold region. We implement it in a commercial C-SKY CK802 processor based on an SMIC 40-nm technology. The result shows that it improves the energy efficiency by 68% compared with the non-EDAC design and lowers the total power by 28.72% over the conventional EDAC design at 0.6 V.
Auteurs: Tao-Tao Zhu;Jian-Yi Meng;Xiao-Yan Xiang;Xiao-Lang Yan;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1681 - 1693
Editeur: IEEE
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» Error-Resilient Video Encoding Using Parallel Independent Signature Processing
Résumé:
Soft errors resulting from encoding video sequences on unreliable hardware can create significant artifacts in decoded video sequences, contributing to extreme video quality degradation. Modern systems are required to operate under increasingly challenging constraints, including smaller feature sizes and lower operating voltage, increasing the likelihood of soft errors in the video encoding hardware. These conditions are of particular concern for energy-limited battery-operated systems since they may be required to operate in nonideal environments and/or continue operating with a practically depleted energy source. The proposed parallel independent signature processing design performs error detection and mitigation in video encoding hardware, enabling a graceful degradation of quality when encoding by using unreliable hardware. The effects of soft errors are minimized by preventing the error propagation normally associated with errors in encoded video sequences. This allows for the recovery of quality when errors are present in the video encoding system. Conventional video encoding techniques are designed to handle worst case error rates by increasing gate sizes and/or increasing the operating voltage of the system. Such designs have error-rate limits, and when these limits are reached, the systems tend to fail catastrophically, resulting in an unrecoverable signal. The proposed design allows for single upset events to translate into single transient artifacts in a decoded video sequence.
Auteurs: Joshua W. Wells;Abhijit Chatterjee;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 05.-2017, volume: 27, issue:5, pages: 1077 - 1090
Editeur: IEEE
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» ESD Robust Fully Salicided 5-V Integrated Power MOSFET in Submicron CMOS
Résumé:
A novel high electrostatic discharge (ESD), robust fully salicided 5-V integrated CMOS power MOSFET design is developed and demonstrated without the use of conventional salicide blocking ballast resistor. This scheme builds the ballast resistors on the top of the source and drain, without any increase in silicon footprint unlike prior methods, while maintaining standard transistor parametric performance.
Auteurs: Jian-Hsing Lee;Natarajan Mahadeva Iyer;Manjunatha Prabhu;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 623 - 625
Editeur: IEEE
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» Estimate of Ocean Wind Vectors Inside Tropical Cyclones From Polarimetric Radiometer
Résumé:
Microwave polarimetry provides a distinctive opportunity to retrieve wind speed (WS) and wind direction (WD) inside tropical cyclones (TCs) due to the high atmospheric transmissivity through clouds and under rain conditions. A WS retrieval algorithm for WS above 20 m/s in TCs using brightness temperature at 6.8- and 10.7-GHz has been developed and a new set of parameters has been optimized from WindSat TB and the HWind analysis matches. This algorithm is estimated to have an encouraging degree of accuracy for retrieving WS in TCs. For WS above 20 m/s, the mean (std) of the differences between retrieved WS and HWind analysis for 17 TCs from 2003 to 2009 is 0.2 m/s (3.1 m/s). WD signals in the third (T3) and fourth Stokes (T4) parameters at 10.7-, 18.7- and 37-GHz for ocean surfaces in TCs under rain are presented. T3 observations from the WindSat 10.7-, 18.7-, and 37-GHz channels are collocated with the ocean-surface winds from the HWind analysis. The collocated data are binned as a function of WS and WD. The 10.7 GHz T3 data show clear 4-K peak-to-peak directional signals at 30–40 m/s WS after correction for the atmospheric attenuation. The data are fitted by harmonics of the relative azimuth angles between the HWind analysis and radiometer look directions. The new coefficients of WD harmonics are used to retrieve WD in TCs under rain using WindSat T3 and T4 channels. The rms difference between retrieved WD and HWind WD is 24.2.
Auteurs: Xiaobin Yin;Zhenzhan Wang;Qingtao Song;Yingzhu Huang;Ruanyu Zhang;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1701 - 1714
Editeur: IEEE
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» Estimating Sag and Wind-Induced Motion of Overhead Power Lines With Current and Magnetic-Flux Density Measurements
Résumé:
Overhead high-voltage transmission lines (HVTLs) extend over diverse geographic regions under uneven weather conditions, where sag and wind-induced conductor motion poses serious issues for uninterrupted power distribution by HVTLs. Sag reduces the ground clearance of the line, whereas conductor motion may result in phase to phase short circuit, and damage to support structure. A real-time estimate of these factors is deemed important to develop requisite prevention measures. In this paper, we present a novel method to cater for sag and motion estimation in real-world scenarios. Our method can detect a change in sag and conductor motion, whether it is symmetrical or unsymmetrical to one or more conductors. We require uniaxial magnetic-field (MF) sensors mounted at support tower, equal to conductors, and synchronized with current-transformer (CT) data at substation. The sensors provide noncontact MF measurements, which are time stamped and transmitted to the substation. The data are then simultaneously processed along with electric current readings from the CT. For processing, we developed a unified algorithm that first distinguishes variation in sag from motion in conductor. Then, it estimates the corresponding sag or motion in any of the conductors. The method is verified first by numerical simulations, and then with a scaled setup in laboratory. Different test cases were identified by the algorithm. Error remains \leq 1 % for unsymmetrical sag estimation. In addition, trajectory of a conductor in motion is retrieved. Where the root mean square error between actual and retrieved conductor amplitude was only 0.0833 for the observation window of 200 ms.
Auteurs: Arsalan Habib Khawaja;Qi Huang;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 897 - 909
Editeur: IEEE
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» Estimating Soil Salinity Under Various Moisture Conditions: An Experimental Study
Résumé:
Soil salinization is one of the most common land desertification processes that can be found worldwide. It is a certainly severe environment hazard and threatens the stability of ecosystems. As a rapid and inexpensive tool, remote sensing technology combining with the measurements of soil spectra has been widely concerned on identifying and mapping salt effect on lands. However, as effects of the soil moisture often immerge the effects of salt to soil reflectance spectra, soil moisture became a major factor to restrict soil salinity monitoring from soil reflectance. High soil moisture content will lead to failure on soil salinity estimation from soil reflectance data. In this paper, a semianalytical model using an exponent function was developed to estimate soil salt content (SSC) under different moisture levels based on a control laboratory experiment. And the root-mean-square error and mean relative error were 0.799 g/kg and 31.294%, respectively, when the model was applied to estimate SSCs by wet soil reflectance. To sum up, considering both effects of soil moisture and soil salt on soil reflectance, the semianalytical model reduced SSC estimated error. The approach presented in this paper provides a new way of estimating soil salinity from soil spectra under various soil moisture conditions, and it will be a potential application for large-scale SSC mapping.
Auteurs: Xiguang Yang;Ying Yu;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2525 - 2533
Editeur: IEEE
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» Estimating the Accuracy Level Among Individual Detections in Clustered Microcalcifications
Résumé:
Computerized detection of clustered microcalcifications (MCs) in mammograms often suffers from the occurrence of false positives (FPs), which can vary greatly from case to case. We investigate how to apply statistical estimation to determine the number of FPs that are present in a detected MC lesion. First, we describe the number of true positives (TPs) by a Poisson–binomial probability distribution, wherein a logistic regression model is trained to determine the probability for an individual detected MC to be a TP based on its detector output. Afterward, we model the spatial occurrence of FPs in a lesion area by a spatial point process (SPP), of which the distribution parameters are estimated from the detections in the lesion and its surrounding region. Furthermore, to improve the estimation accuracy, we incorporate the Poisson–binomial distribution of the number of TPs into the SPP model using maximum a posteriori estimation. In the experiments, we demonstrated the proposed approach on the detection results from a set of 188 full-field digital mammography (FFDM) images (95 cases) by three existing MC detectors. The results showed that there was a strong consistency between the estimated and the actual number of TPs (or FPs) for these detectors. When the fraction of FPs in detection was varied from 20% to 50%, both the mean and median values of the estimation error were within 11% of the total number of detected MCs in a lesion. In particular, when the number of FPs increased to as high as 11.38 in a cluster on average, the error was 2.51 in the estimated number of FPs. In addition, lesions estimated to be more accurate in detection were shown to have better classification accuracy (for being malignant or benign) than those estimated to be less accurate.
Auteurs: María V. Sainz de Cea;Robert M. Nishikawa;Yongyi Yang;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 05.-2017, volume: 36, issue:5, pages: 1162 - 1171
Editeur: IEEE
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» Estimation and Attitude Control in CONASAT's Nominal Operation Mode: An Approach for SDRE Filter and PID Control
Résumé:
CubeSat attracted interest of international community with numerous studies being developed in some universities, schools or even space enthusiastic. Miniaturization of components and use of conventional electronics reduced costs with space projects, that previously restricted access to space to only a few nations at costs of several million dollars. So, governments and space agencies, especially in developing nations, has begun to invest in small satellite projects, because now they can have space missions at low cost. Thus, the National Institute for Space Research (INPE), in Brazil, has planning some CubeSat missions as an academic tool to spread the space technology across the country to universities and researches. One of the missions in development is the Nanosatellite Constellation for Environmental Data Collection (CONASAT). This project intends to launch at least two small satellites to replace the SCD1 and SCD2 satellites of the Brazilian's environmental data collection system. The main objective of this paper is to propose state estimation technique, known as State-Dependent Riccati Equation (SDRE), together with a PID controller based on attitude error given by the Euler angle and axis for nominal mode attitude control of CONASAT. Simulations were performed using an open computational tool for attitude and orbit simulation.
Auteurs: Brehme Dnapoli Reis de Mesquita;Helio Koiti Kuga;Valdemir Carrara;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 835 - 842
Editeur: IEEE
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» Estimation of Current and Sag in Overhead Power Transmission Lines With Optimized Magnetic Field Sensor Array Placement
Résumé:
Power distribution mechanism in smart grid necessitates the development of an easy-to-install and contactless sensing system to monitor the operational state of overhead high-voltage transmission lines. Here, we propose a robust phase current and sag estimation method at support structures. Novelty in our work is the use of dual-axis magnetic field (MF) sensors equal to the number of phase conductors. This is realized by installing an array of sensors optimally placed in the same vertical plane as of conductors on the tower. The optimal position of sensor array was found while minimizing the condition number of governing linear system close to unity. For any circuit configuration, our method processes the sensed MF vector projections through a linear system, which is based on the Biot–Savart law. It considers the practical factors, such as sag, span length, and sensor-to-conductor distance. An algorithm is then designed to estimate the electric current and sag by iterative comparison between the measured and calculated MF. The method is first tested by numerical simulations for a typical one-circuit configuration, which involves three scenarios of symmetrical and unsymmetrical sag in conductors. The algorithm converges to a maximum error of $le 1$ % within 300 iterations. We then experimentally verify our scheme on a scaled laboratory setup. Retrieved current and sag values were verified with the readings from ammeter and vernier caliper, respectively. The results prove the viability of our approach within $le 2.6$ % deviation for current and $le 1$ % for sag in all conductors.
Auteurs: Arsalan Habib Khawaja;Qi Huang;Jian Li;Zhenyuan Zhang;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 10
Editeur: IEEE
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» Estimation of Sparse Massive MIMO-OFDM Channels With Approximately Common Support
Résumé:
In this letter, we reveal that in the massive multiple-input multiple-output system with large bandwidth, sub-channels of orthogonal frequency division multiplexing share approximately sparse common support due to the frequency difference of subcarriers. We use the approximate message passing with nearest neighbor sparsity pattern learning (AMP-NNSPL) algorithm to adaptively learn the underlying structure for improving the accuracy of channel estimation, where the learning strategy is newly derived by solving an optimization problem. In addition, the performance of the AMP-NNSPL is well predicted by the state evolution. Simulation results demonstrate the superiority of the algorithm in systems with large bandwidth.
Auteurs: Xincong Lin;Sheng Wu;Linling Kuang;Zuyao Ni;Xiangming Meng;Chunxiao Jiang;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1179 - 1182
Editeur: IEEE
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» Estimation of the Lens Distortion Model by Minimizing a Line Reprojection Error
Résumé:
Most techniques for camera calibration that use planar calibration patterns require the computation of a lens distortion model and a homography. Both are simultaneously refined using a bundle adjustment that minimizes the reprojection error of a collection of points when projected from the scene onto the camera sensor. These points are usually the corners of the rectangles of a calibration pattern. However, if the lens shows a significant distortion, the location and matching of the corners can be difficult and inaccurate. To cope with this problem, instead of point correspondences, we propose to use line correspondences to compute the reprojection error. We have designed a fully automatic algorithm to estimate the lens distortion model and the homography by computing line correspondences and minimizing the line reprojection error. In the experimental setup, we focus on the analysis of the quality of the obtained lens distortion model. We present some experiments that show that the proposed method outperforms the results obtained by standard methods to compute lens distortion models based on line rectification.
Auteurs: Daniel Santana-Cedrés;Luis Gomez;Miguel Alemán-Flores;Agustín Salgado;Julio Esclarín;Luis Mazorra;Luis Alvarez;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2848 - 2855
Editeur: IEEE
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» Evaluating Gaussian and Rayleigh-Based Mathematical Models for T and P-waves in ECG
Résumé:
This paper presents a comparative study of modelling and segmentation of P and T waves in electrocardiograms, using three different mathematical models: Gaussian function, a composition of two Gaussian functions and Rayleigh probability density function (Rayleigh pdf). In order to evaluate the adaptability and the matching degree between each model and each characteristic wave, we compute the normalized root mean square (RMS) error, as well as the evolution of the fitting parameters related to each kernel throughout ECG records from the well-known QT database. Concerning the delineation of P and T-waves, we apply Wavelet Transform for estimating T-wave and P-wave peak locations and combine each developed model with an approach based on the computation of Trapezium's area to locate the end point of each T-wave and the beginning and end point of each P-wave. The composition of two Gaussian functions has produced the most accurate results concerning wave modelling, providing average values of normalized RMS errors equal to 9,15% and 18,70%, respectively for T-wave and P-wave. Rayleigh pdf provided the most stable fitting parameters. For T-wave end location, the most accurate results were computed when using the kernel composition of two Gaussian functions, for which the average time error was 4,49 ± 14,32 ms. For P-wave begin and P-wave end locations, the most accurate results were computed when using kernel Rayleigh pdf, for which the average time errors were, respectively, -4,23 ± 14,84 ms and 2,26 ± 13,14 ms.
Auteurs: Joao Paulo do Vale Madeiro;Elves Mauro Boa Esperanca dos Santos;Paulo Cesar Cortez;John Hebert da Silva Felix;Fernando Soares Schlindwein;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 843 - 853
Editeur: IEEE
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» Evaluating Generating Unit Unavailability Using Bayesian Power Priors
Résumé:
Generating unit unavailability assessment is an important task in the power system generation expansion planning aimed at managing an acceptable degree of security of supply. In the case of the newly installed or planned units, the sample size of the data for unavailability assessment is limited and inadequate to provide the desired accuracy in the unavailability estimation. A new concept based on the Bayesian power prior approach has been developed to utilize the data from similar generating units. The original contribution of the present work is a model that incorporates the data of unavailability from other generating units into the statistical analysis of unavailability of the analysed generating unit to improve the accuracy of the estimation. The empirical results show that for unavailability estimation, the power prior Bayesian approach exhibits better than the classical statistical approach in both the standard error of estimate and confidence interval as the measures of accuracy.
Auteurs: Ivan Lorencin;Miloš Pantoš;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2315 - 2323
Editeur: IEEE
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» Evaluation of 4-D Reaction Integrals in the Method of Moments: Coplanar Element Case
Résumé:
Recently, the benefits of simultaneously treating source and testing integrals in the numerical evaluation of 4-D reaction integrals have been reported. The reported schemes usually first transform the reaction integral to parametric coordinates, and some combination of radial, angular, and/or line segment integrals is then used to treat coincident, edge-adjacent, or vertex-adjacent triangular source and test element pairs. However, advantages of the reported approaches are tempered by their lack of generality and severely degraded performance on poorly shaped elements, the latter caused primarily by the parametric transformations’ severe distortion of the kernel’s circularly concentric level contours. Here, for coplanar element pairs and kernels with 1/ $R$ singularities, we apply the surface divergence theorem twice to obtain a novel formula for 4-D reaction integrals, generalizing earlier schemes while retaining their benefits and without distorting the original configuration space. Numerical results illustrate the method’s efficiency, which is improved by employing appropriate transformations to further smooth the resulting integrands and hence accelerate their convergence. The reaction integral formula can be extended to noncoplanar elements.
Auteurs: Donald R. Wilton;Francesca Vipiana;William A. Johnson;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2479 - 2493
Editeur: IEEE
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» Evaluation of Load Frequency Control Performance Based on Standard Deviational Ellipses
Résumé:
This paper discusses new criterion for the evaluation of load frequency control (LFC) performance. The proposed LFC performance evaluation is based on a standard deviational ellipse that characterizes a bivariate relationship between the frequency deviation and the area's interchange power variation. The standard deviational ellipse is evaluated using Tyler's maximum-likelihood estimator, which is distribution-free within the family of elliptical distributions. In addition, a target standard deviational ellipse is proposed, using predefined values for a target frequency bound and the area's frequency bias. The presented approach is based on the accordance of the estimated ellipse with the target ellipse, resulting in several grades for the LFC performance. A comparison of the proposed criterion is made with other LFC performance criteria known from the literature. Extensive measurements were applied, and the obtained results show the correctness of the proposed approach.
Auteurs: Boštjan Polajžer;Robert Brezovnik;Jožef Ritonja;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2296 - 2304
Editeur: IEEE
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» Evaluation of Potential and Impedance Integrals in Analysis of Axially Symmetric Metallic Structures to Prescribed Accuracy Up To Machine Precision
Résumé:
This paper presents a novel method for evaluating potential and impedance integrals appearing in the method of moment analysis of arbitrary axially symmetric metallic structures based on exact wire kernel and higher order bases. Due to new variable transforms proposed for singularity cancellation and smoothing the integrands, high accuracy up to machine precision is achieved using relatively small number of integration points. Simple formulas are determined for predicting a number of integration points needed for prescribed accuracy. Benefits of high-precision evaluation of impedance integrals are illustrated on a number of numerical examples.
Auteurs: Aleksandra J. Krneta;Branko M. Kolundzija;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2526 - 2539
Editeur: IEEE
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» Evaluation of the Range Accuracy and the Radiometric Calibration of Multiple Terrestrial Laser Scanning Instruments for Data Interoperability
Résumé:
Terrestrial laser scanning (TLS) data provide 3-D measurements of vegetation structure and have the potential to support the calibration and validation of satellite and airborne sensors. The increasing range of different commercial and scientific TLS instruments holds challenges for data and instrument interoperability. Using data from various TLS sources will be critical to upscale study areas or compare data. In this paper, we provide a general framework to compare the interoperability of TLS instruments. We compare three TLS instruments that are the same make and model, the RIEGL VZ-400. We compare the range accuracy and evaluate the manufacturer's radiometric calibration for the uncalibrated return intensities. Our results show that the range accuracy between instruments is comparable and within the manufacturer's specifications. This means that the spatial XYZ data of different instruments can be combined into a single data set. Our findings demonstrate that radiometric calibration is instrument specific and needs to be carried out for each instrument individually before including reflectance information in TLS analysis. We show that the residuals between the calibrated reflectance panels and the apparent reflectance measured by the instrument are greatest for highest reflectance panels (residuals ranging from 0.058 to 0.312).
Auteurs: Kim Calders;Mathias I. Disney;John Armston;Andrew Burt;Benjamin Brede;Niall Origo;Jasmine Muir;Joanne Nightingale;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2716 - 2724
Editeur: IEEE
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» Evaluation Scheme for EMI of Train Body Voltage Fluctuation on the BCU Speed Sensor Measurement
Résumé:
The voltage fluctuation between the train body (TB) and the train’s wheel axis (TB voltage fluctuation for short), might cause electromagnetic interference (EMI) on brake control unit (BCU) speed sensor in some high-speed trains (HSTs), which may cause faulty measurement of train speed and incorrect operation of train door. Using a relevant event that occurred in China railways high-speed 380CL-type train as case study, this paper presents an evaluation scheme for the EMI influence of TB voltage fluctuation on the speed measurement of BCU speed sensor. First, the EMI channels are researched, and a model representing the relation between TB voltage and voltage signal reflecting measured speed is deduced. Second, an evaluation scheme for speed measurement influenced by EMI is designed on this basis, where TB voltage and voltage signal reflecting measured speed are taken as the input and the output of model, respectively. The evaluation aimed at EMI is realized by judging the correctness of model output. Later, a real-life experiment is performed in the Chinese Nanjing station to verify the validity and feasibility of evaluation scheme. Last, some application studies are made to evaluate the presented scheme under multiple specific conditions, such as different TB contact conditions or different train speeds. The comparison results illustrate that the scheme can not only provide an opportunity to judge the correctness of speed measurement under the premise of collecting TB voltages, but also provide references in taking timely measures to prevent faulty speed measurement such as weakening TB voltage fluctuations.
Auteurs: Ke Huang;Zhigang Liu;Feng Zhu;Zongsheng Zheng;Ye Cheng;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 1046 - 1057
Editeur: IEEE
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» Event-Triggered Optimal Control for Partially Unknown Constrained-Input Systems via Adaptive Dynamic Programming
Résumé:
Event-triggered control has been an effective tool in dealing with problems with finite communication and computation resources. In this paper, we design an event-triggered control for nonlinear constrained-input continuous-time systems based on the optimal policy. Constraints on controls are handled using a bounded function. To learn the optimal solution with partially unknown dynamics, an online adaptive dynamic programming algorithm is proposed. The identifier network, the critic network, and the actor network are employed to approximate the unknown drift dynamics, the optimal value, and the optimal policy, respectively. The identifier is tuned based on online data, which further trains the critic and actor at triggering instants. A concurrent learning technique repeatedly uses past data to train the critic. Stability of the closed-loop system, and convergence of neural networks to the optimal solutions are proved by Lyapunov analysis. In the end, the algorithm is applied to the overhead crane system to observe the performance. The event-triggered optimal controller with constraints stabilizes the system and consumes much less sampling times.
Auteurs: Yuanheng Zhu;Dongbin Zhao;Haibo He;Junhong Ji;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4101 - 4109
Editeur: IEEE
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» Evidential Fusion Based Technique for Detecting Landslide Barrier Lakes From Cloud-Covered Remote Sensing Images
Résumé:
Landslide barrier lakes usually form quickly after disasters and require very timely remote sensing images to monitor the land-cover change. However, cloud-free images are not always available in emergency situations. This paper provides a method to fuse multitemporal cloud-covered images for change detection, based on the evidential fusion framework. First, the frame of discernment is defined by postclassification comparison results. Second, a way of measuring the basic belief assignment (BBA) is introduced based on the confusion matrixes. Next, a simple BBA redistribution process is proposed to deal with cloud coverage problems. Then, the complementary and redundant information from the input images can be fused following the evidence combination and decision making rules in the evidential fusion framework. Finally, the land-cover change map can be derived. Thanks to the Dempster–Shafer evidence theory, the proposed method can complete the change detection process—including data fusion and cloud removal—in an integrated manner. The proposed method is applied to detect the landslide barrier lake in a real case study, using a series of cloud-covered images from the GF-1 satellite. Result comparisons show that the proposed method is more effective than some basic fusion strategies that perform change detection and cloud removal in separate steps. Then, some approaches to improve the proposed method are discussed: introducing new evidence combination rule, improving the classification accuracy, and adding new evidences. All the results indicate the potential of evidential fusion for change detection from cloud-covered images.
Auteurs: Xi Chen;Jing Li;Yunfei Zhang;Weiguo Jiang;Liangliang Tao;Wei Shen;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1742 - 1757
Editeur: IEEE
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» Evolutionary Nonnegative Matrix Factorization Algorithms for Community Detection in Dynamic Networks
Résumé:
Discovering evolving communities in dynamic networks is essential to important applications such as analysis for dynamic web content and disease progression. Evolutionary clustering uses the temporal smoothness framework that simultaneously maximizes the clustering accuracy at the current time step and minimizes the clustering drift between two successive time steps. In this paper, we propose two evolutionary nonnegative matrix factorization (ENMF) frameworks for detecting dynamic communities. To address the theoretical relationship among evolutionary clustering algorithms, we first prove the equivalence relationship between ENMF and optimization of evolutionary modularity density. Then, we extend the theory by proving the equivalence between evolutionary spectral clustering and ENMF, which serves as the theoretical foundation for hybrid algorithms. Based on the equivalence, we propose a semi-supervised ENMF (sE-NMF) by incorporating a priori information into ENMF. Unlike the traditional semi-supervised algorithms, a priori information is integrated into the objective function of the algorithm. The main advantage of the proposed algorithm is to escape the local optimal solution without increasing time complexity. The experimental results over a number of artificial and real world dynamic networks illustrate that the proposed method is not only more accurate but also more robust than the state-of-the-art approaches.
Auteurs: Xiaoke Ma;Di Dong;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 05.-2017, volume: 29, issue:5, pages: 1045 - 1058
Editeur: IEEE
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» Evolutive Strategy to Inducing Chaos in a Gene Regulatory Network
Résumé:
In the present paper we propose an Evolutionary Strategy of Multiobjective Optimization like an alternative method to induce chaotic dynamics in a genetic regulatory network, called V-System, which was created by joining two systems of equations: one oscillating and one with a hysteresis dynamics. The genetic regulatory network is represented by four differential equations with seventeen parameters, which variables show the proteins concentrations. The multiobjective fitness function is built like a linear combination, involving a numerical approximation to Lyapunov exponents in the system, which is only dependent of the parameters fixed values. The optimization problem optimum represents the set of parameters values where the system is more chaotic. We present the numerical results of the evolutionary strategy and we show the convergence of the individuals in the population to the critical points in one of the subsystems in the V-System.
Auteurs: Hector Guardado Muro;Eunice Esther Ponce de Leon Senti;Aurora Torres Soto;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 916 - 921
Editeur: IEEE
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» Exact and Approximate Capacitance and Force Expressions for the Electrostatic Interaction Between Two Equal-Sized Charged Conducting Spheres
Résumé:
We analyze the electrostatic interaction between two equal-sized charged conducting spheres. We obtain exact closed-form expressions for the capacitance coefficients and the electrostatic force in terms of the special q -digamma function. Additionally, we provide simpler-to-use approximate expressions for the capacitance coefficients and the force between the spheres, and then compare the approximations with the exact results.
Auteurs: Shubho Banerjee;Mason Levy;McKenna Davis;Blake Wilkerson;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2455 - 2460
Editeur: IEEE
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» Exact Moderate Deviation Asymptotics in Streaming Data Transmission
Résumé:
In this paper, a streaming transmission setup is considered, where an encoder observes a new message in the beginning of each block and a decoder sequentially decodes each message after a delay of $T$ blocks. In this streaming setup, the fundamental interplay between the coding rate, the error probability, and the blocklength in the moderate deviations regime is studied. For output symmetric channels, the moderate deviations constant is shown to improve over the block coding or non-streaming setup by exactly a factor of $T$ for a certain range of moderate deviations scalings. For the converse proof, a more powerful decoder, to which some extra information is fedforward is assumed. The error probability is bounded first for an auxiliary channel and this result is translated back to the original channel by using a newly developed change-of-measure lemma, where the speed of decay of the remainder term in the exponent is carefully characterized. For the achievability proof, a known coding technique that involves a joint encoding and decoding of fresh and past messages is applied with some manipulations in the error analysis.
Auteurs: Si-Hyeon Lee;Vincent Y. F. Tan;Ashish Khisti;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2726 - 2736
Editeur: IEEE
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» Experience With a Multidisciplinary, Team-Taught Smart Grid Cyber Infrastructure Course
Résumé:
Electric power systems are going through a major upgrade with the integration of advanced technologies to enable the smarter electric grid (SEG). The SEG will use information and communications technology to have enhanced controllability and will become more interactive. This ongoing change also necessitates educating professionals and future generation of engineers to manage evolving complexity of the electric grid. This paper presents experiences in the design and teaching of a unique multidisciplinary team-taught course on smart grid cyber infrastructure to provide a new generation of engineers with a solid foundation of smart grid concepts and their associated challenges. This paper identifies the course topics covered, learning objectives, and assessment activities for the class as well as lessons learned based on course evaluations obtained from multiple offerings. All of the course material is available in public domain and can be easily adopted at another educational institution.
Auteurs: Anurag K. Srivastava;Adam L. Hahn;Olusola O. Adesope;Carl H. Hauser;David E. Bakken;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2267 - 2275
Editeur: IEEE
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» Experimental Characterization of the Thermal Time Constants of GaN HEMTs Via Micro-Raman Thermometry
Résumé:
Gallium nitride (GaN) high-electron mobility transistors (HEMTs) are a key technology for realizing next generation high-power RF amplifiers and high-efficiency power converters. However, elevated channel temperatures due to self-heating often severely limit their power handling capability. Although the steady-state thermal behavior of GaN HEMTs has been studied extensively, significantly fewer studies have considered their transient thermal response. In this paper, we report a methodology for measuring the transient temperature rise and thermal time constant spectrum of GaN HEMTs via time-resolved micro-Raman thermometry with a temporal resolution of 30 ns. We measured a broad spectrum of time constants from $approx 130$ ns to $approx 3.2$ ms that contribute to the temperature rise of an ungated GaN-on-SiC HEMT due to aggressive, multidimensional heat spreading in the die and die-attach. Our findings confirm previous theoretical analysis showing that one or two thermal time constants cannot adequately describe the transient temperature rise and that the temperature reaches steady-state at $approx {16}L^{{2}}/pi ^{{2}}alpha $ , where $L$ and ${alpha }$ are the thickness and thermal diffusivity of the substrate. This paper provides a practical methodology for validating transient thermal models of GaN HEMTs and for obtaining experimental values of the thermal resistances and capacitances for compact electrothermal modeling.
Auteurs: Kevin R. Bagnall;Omair I. Saadat;Sameer Joglekar;Tomás Palacios;Evelyn N. Wang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2121 - 2128
Editeur: IEEE
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» Experimental Realization of Thermal Stability Enhancement of Nickel Germanide Alloy by Using TiN Metal Capping
Résumé:
In this paper, we demonstrated the enhancement of thermal stability of nickel germanide (NiGe) alloy up to 600 °C by using titanium nitride (TiN) metal capping. A high ${I}_{ mathrm{scriptscriptstyle ON}}/{I}_{ mathrm{scriptscriptstyle OFF}}$ ratio of $2.9 times 10^{5}$ was achieved by capping TiN metal on Ni for NiGe alloy formation at 600 °C. Detailed analyses were performed for realizing the mechanism for TiN capping on NiGe/Ge, including vertical element diffusion profile observation through depth-profiling X-ray photoelectron spectroscopy (XPS), element diffusion distribution by energy-dispersive X-ray spectroscopy mapping, and direct junction leakage current path detection by conductive atomic force microscopy. The experimental results indicated that TiN capping can reduce the risk of agglomeration and form a graded NiGe/Ge Schottky junction that is beneficial for suppressing the degradation of junction leakage. Subsequently, we compared the electrical performance of TiN/NiGe/n-Ge at various N/Ti ratios of TiNs. Based on the depth-profiling XPS results and electrical performance, TiN with an N/Ti ratio of approximately 1:1 can resist the Ni and Ge diffusion, which facilitates the suppression of the agglomeration process. However, the TiN capping layers with an N/Ti ratio of less than approximately 1:1 (Ti-rich) were not favorable for resisting Ni and Ge diffusion.
Auteurs: Chen-Han Chou;Yi-He Tsai;Chung-Chun Hsu;Yu-Hau Jau;Yu-Hsien Lin;Wen-Kuan Yeh;Chao-Hsin Chien;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2314 - 2320
Editeur: IEEE
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» Experimental Study of Electrically Compact Retrodirective Monopole Antenna Arrays
Résumé:
Auto-pointing and angular super-resolution properties of the radiation patterns generated by an electrically compact retrodirective monopole antenna array are demonstrated experimentally for the first time. The operation of electrically compact (element spacings less than one-fifth of the radiation wavelength) retrodirective antenna arrays that were theoretically considered in our previous work is confirmed by measurement. Particularly, it is shown that the direction-of-arrival information carried by an incident electromagnetic wave can be encoded into the evanescent near field of an electrically small resonant antenna array with a spatial rate higher than the spatial oscillation rate of the incident field in free space. This observation is supported by the near-field measurements, demonstrating that the magnitude of the scattered (evanescent) field in the array environment can exceed the magnitude of the incident field in free space by at least 6 dB. Retrodirective array antenna matching and the feasibility of a frequency-division full-duplex communication link based on the proposed antenna arrays are also discussed.
Auteurs: Oleksandr Malyuskin;Vincent F. Fusco;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2339 - 2347
Editeur: IEEE
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» Experimental Study on Deflection Behavior of Vacuum Arcs Under the Influence of External Transverse Magnetic Field
Résumé:
In real power system, when the three-phase short-circuit fault occurs, the vacuum arc in one phase will be influenced by the transverse magnetic field generated by neighbor phases and bus bars. This kind of effect is the main cause of the unstable arc and deflected erosion of contact plates, which leads to the failure of vacuum circuit breakers interruption. The objective of this paper is to get more insight into the influence of external transverse magnetic field (ETMF) on vacuum arc’s behavior. The experiments were conducted in a demountable vacuum chamber with pressure about $10^{-4}$ Pa. The cup-type axial magnetic field contacts were used, whose material was pure copper and the diameter is 35 mm. The uniform ETMF in the arc region was generated by two parallel bulk permanent magnets. The experiments were conducted under different ETMFs (0, 15, and 25 mT) and current levels (1-, 2.5-, and 4-kA rms) with different gap distances (6, 8.5, and 11 mm). The videos of arc column were recorded by a high-speed charge-coupled device camera. Under the action of ETMF, the vacuum arc got deflected. Due to the retrograde motion of cathode spots and Ampere force acting on arc column, the deflection behaviors during three typical periods (that is, initial, peak value, and close-to-current-zero period) were different. Moreover, the deflection level of vacuum arc at current peak value moment was greatly impacted by ETMF and gap distance. Larger the ETMF and gap distance were, higher the deflection level at current peak value moment was. The simulation results of arc deflection based on magnetic-hydrodynamic model were in agreement with experimental results in trends.
Auteurs: Shenli Jia;Zhonghao Qian;Lijun Wang;Wein Xin Shi;Jie Deng;Xiao Zhang;Zongqian Shi;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 868 - 874
Editeur: IEEE
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» Experimental Study on Flexible ZnO Based Nanogenerator Using Schottky Contact for Energy Harvesting Applications
Résumé:
This paper presents the synthesis and implementation of a metal-insulator-semiconductor-type energy harvester. The proposed harvester generates power from ambient vibration. The flexible nanogenerator (NG) is developed from well- aligned ZnO nanorods (NRs) on kapton substrate with ITO sputtered bottom contact using the low-temperature hydrothermal method. PMMA insulation region is coated over NRs with silver (Ag) as top electrode to reduce the external screening effect thereby improving the output signal strength. The crystalline and morphological properties of the NRs are studied using X-ray diffraction, field emission scanning electron microscopy analysis, Fourier transform infrared spectroscopy, and photoluminescence.The current–voltage characteristics of the ZnO NRs exhibited a clear rectifying behavior, attributed to the formation of a Schottky contact between ZnO and Ag contact with an insulation of PMMA layer. An experimental study to evaluate the device performance is carried out using tip excitation method. The synthesized NG generates open-circuit voltage of 400 mV, circuit current across optimum load of 10 kΩ is 30 μA, and giving a maximum power density of 9 μ Wcm–2 at a force of 0.5 N at 12 Hz. Furthermore, the impedance analysis is performed for estimating the relationship between screening effects and RC time constant (T RC).
Auteurs: Kirubaveni Savarimuthu;Govindaraj Rajamanickam;Radha Shankararajan;Ramasamy Perumal;Arokiyadoss Rayarfrancis;
Apparue dans: IEEE Transactions on Nanotechnology
Date publication: 05.-2017, volume: 16, issue:3, pages: 469 - 476
Editeur: IEEE
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» Experimental Validation of a Fast Forward Model for Guided Wave Tomography of Pipe Elbows
Résumé:
Ultrasonic guided wave tomography (GWT) methods for the detection of corrosion and erosion damage in straight pipe sections are now well advanced. However, successful application of GWT to pipe bends has not yet been demonstrated due to the computational burden associated with the complex forward model required to simulate guided wave propagation through the bend. In a previous paper [Brath et al., IEEE Trans. Ultrason., Ferroelectr., Freq. Control, vol. 61, pp. 815–829, 2014], we have shown that the speed of the forward model can be increased by replacing the 3-D pipe bend with a 2-D rectangular domain in which guided wave propagation is formulated based on an artificially inhomogeneous and elliptically anisotropic (INELAN) acoustic model. This paper provides further experimental validation of the INLEAN model by studying the traveltime shifts caused by the introduction of shallow defects on the elbow of a pipe bend. Comparison between experiments and simulations confirms that a defect can be modeled as a phase velocity perturbation to the INLEAN velocity field with accuracy that is within the experimental error of the measurements. In addition, it is found that the sensitivity of traveltime measurements to the presence of damage decreases as the damage position moves from the interior side of the bend (intrados) to the exterior one (extrados). This effect is due to the nonuniform ray coverage obtainable when transmitting the guided wave signals with one ring array of sources on one side of the elbow and receiving with a second array on the other side.
Auteurs: Alex J. Brath;Francesco Simonetti;Peter B. Nagy;Geir Instanes;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 859 - 871
Editeur: IEEE
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» Experimental Verification of an Electrical Drive Fed by a Modular Multilevel TSBC Converter When the Motor Frequency Gets Closer or Equal to the Supply Frequency
Résumé:
This paper provides an experimental discussion on an adjustable-speed electrical drive fed by a modular multilevel triple-star bridge-cell (TSBC) converter. The TSBC converter is suitable for medium-voltage high-power motor drives with regenerative braking. However, it suffers from capacitor-voltage fluctuation that becomes more serious as the motor frequency gets closer or equal to the supply frequency. This paper presents a practical solution of it with an acceptable increase in all the nine cluster currents. The solution is characterized by a motor-magnetizing-current controller that makes a significant contribution to theoretically eliminating the low-frequency component contained in each capacitor voltage. Experimental waveforms, which are obtained from a three-phase downscaled model rated at 400 V and 15 kW, verify exhibit satisfactory start-up performance from a standstill to the rated motor frequency that is equal to the supply frequency.
Auteurs: Wataru Kawamura;Yuto Chiba;Makoto Hagiwara;Hirofumi Akagi;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2297 - 2306
Editeur: IEEE
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» Exploiting Non-Orthogonal Multiple Access in Cooperative Relay Sharing
Résumé:
We propose and investigate a dual-hop cooperative relaying scheme using non-orthogonal multiple access (NOMA) (termed NOMA-RS), where two sources communicate with their corresponding destinations in parallel over the same frequency band via a common relay. In this scheme, after receiving symbols transmitted in parallel by both sources with different allocated powers, the relay forwards a super-position coded composite signal using NOMA to the destinations. One of the main benefits of NOMA-RS is that multiple (two) sources can share the same relay, unlike the previous works. Through the simulations and mathematical analysis, we demonstrate the effectiveness of the proposed protocol in terms of ergodic sum capacity by considering perfect and imperfect successive interference cancellation.
Auteurs: Md. Fazlul Kader;Muhammad Basit Shahab;Soo Young Shin;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1159 - 1162
Editeur: IEEE
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» Exploiting Overlapped Bands for Efficient Broadcast in Multichannel Wireless Networks
Résumé:
In wireless networks, broadcasting is a fundamental communication primitive for network management and information sharing. However, in multichannel networks, broadcast efficiency is very poor as devices are distributed across various channels. Thus, a sender tries all channels to broadcast a single message, causing large overhead. In this paper, we propose a novel, drastically different scheme for efficient broadcast in multichannel networks. Our scheme leverages an overlapped band of adjacent channels, which is the frequency range that partially overlapped channels share within their channel boundaries. Specifically, a sender advertises a rendezvous channel through the overlapped band of adjacent channels; message sharing is done on the rendezvous channel. Our scheme employs signaling via overlapped band (SOB), which defines a new signal processing mechanism for communication via the overlapped band. SOB is integrated with the following Multiple Access Control (MAC) layer mechanisms: 1) Reserve idle spectrum fragment to reduce waiting time, 2) multisender agreement on rendezvous channel to support multisender broadcasts, and 3) reinforce switch notification to reduce the residing time at a wrong channel. Our scheme can also be integrated with two remarkably simple but efficient mechanisms for improving the packet delivery ratio and reducing delay in a multiple contention domain. We implemented our scheme on the SORA software radio platform. Experimental results validated communication through the overlapped band. Intensive simulation studies showed that our scheme dramatically outperformed a previous approach.
Auteurs: Jae-Han Lim;Katsuhiro Naito;Ji-Hoon Yun;Mario Gerla;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4355 - 4370
Editeur: IEEE
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» Exploring Data Validity in Transportation Systems for Smart Cities
Résumé:
Efficient urban transportation systems are widely accepted as essential infrastructure for smart cities, and they can highly increase a city�s vitality and convenience for residents. The three core pillars of smart cities can be considered to be data mining technology, IoT, and mobile wireless networks. Enormous data from IoT is stimulating our cities to become smarter than ever before. In transportation systems, data-driven management can dramatically enhance the operating efficiency by providing a clear and insightful image of passengers� transportation behavior. In this article, we focus on the data validity problem in a cellular network based transportation data collection system from two aspects: internal time discrepancy and data loss. First, the essence of time discrepancy was analyzed for both automated fare collection (AFC) and automated vehicular location (AVL) systems, and it was found that time discrepancies can be identified and rectified by analyzing passenger origin inference success rate using different time shift values and evolutionary algorithms. Second, the algorithmic framework to handle location data loss and time discrepancy was provided. Third, the spatial distribution characteristics of location data loss events were analyzed, and we discovered that they have a strong and positive relationship with both high passenger volume and shadowing effects in urbanized areas, which can cause severe biases on passenger traffic analysis. Our research has proposed some data-driven methodologies to increase data validity and provided some insights into the influence of IoT level data loss on public transportation systems for smart cities.
Auteurs: Yongxin Liu;Xiaoxiong Weng;Jiafu Wan;Xuejun Yue;Houbing Song;Athanasios V. Vasilakos;
Apparue dans: IEEE Communications Magazine
Date publication: 05.-2017, volume: 55, issue:5, pages: 26 - 33
Editeur: IEEE
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» Exploring Tag Distribution in Multi-Reader RFID Systems
Résumé:
Radio Frequency Identification (RFID) brings a revolutionary change in a range of applications by automatically monitoring and tracking products. With the proliferation of RFID-enabled applications, multiple readers are needed for ensuring the full coverage of numerous RFID tags. In this paper, we focus on the tag distribution problem in multi-reader RFID systems. The problem is to fast identify the tag set beneath each reader, which is a fundamental premise of efficient product inventory and management. Only with such tag set information can we localize specific tags in a reader and expedite the tag query information collection. As an RFID system usually contains a large number of tags and multiple readers, the traditional solution to identify tags by individual readers is highly time inefficient. We propose an Inference-Based protocol (IB) that identifies the tag distribution based on information inference rules and the aggregated physical signals to improve operational efficiency. In our protocol, three kinds of inference rules based on internal information reported by a single reader, external information shared by multiple readers, and history information retained by the system are fully exploited to infer tag distribution. With these rules, all readers can cooperatively work together and quickly obtain the tag distribution in the system. We also build a prototype RFID system using the USRP-based reader and WISP programmable tags, and then implement the IB protocol. The experimental results and extended simulations show that IB outperforms the state-of-the-art protocols.
Auteurs: Feng Zhu;Bin Xiao;Jia Liu;Bin Wang;Qingfeng Pan;Li-Jun Chen;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1300 - 1314
Editeur: IEEE
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» Extended Efficiency Range, Equal-Cell Doherty Amplifier Design Using Explicit Circuit Model
Résumé:
This letter presents the design of a symmetrical Doherty power amplifier (DPA) with extended high-efficiency range by using a new and explicit circuit model. Theoretical analysis reveals that by the adjustment of the electrical length of transmission line sections in the proposed circuit model, new DPA variants with simple circuitry and enhanced output back-off (OBO) are obtained. For experimental verification, a 42-dBm, 2-GHz DPA with OBO of 9.5 dB was designed and fabricated using identical GaN HEMT devices. Under continuous-wave stimulation, measurement results indicate good Doherty behavior can be obtained with 9.5-dB back-off efficiency of 51%–61% and saturation efficiency of 68%–72% over 1.85–2.1 GHz. Moreover, with single carrier WCDMA signal (centered at 2.1 GHz) and peak-to-average power ratio of 9.6 dB, the proposed design is found to deliver an average drain efficiency of 58% and adjacent channel leakage power of −47 dBc at an output power level of 32.5 dBm.
Auteurs: Xiao-Hu Fang;Hao-Yu Liu;Kwok-Keung M. Cheng;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 497 - 499
Editeur: IEEE
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» Extrafoveal Video Extension for an Immersive Viewing Experience
Résumé:
Between the recent popularity of virtual reality (VR) and the development of 3D, immersion has become an integral part of entertainment concepts. Head-mounted Display (HMD) devices are often used to afford users a feeling of immersion in the environment. Another technique is to project additional material surrounding the viewer, as is achieved using cave systems. As a continuation of this technique, it could be interesting to extend surrounding projection to current television or cinema screens. The idea would be to entirely fill the viewer's field of vision, thus providing them with a more complete feeling of being in the scene and part of the story. The appropriate content can be captured using large field of view (FoV) technology, using a rig of cameras for 110 ^{\circ} to 360 ^{\circ} capture, or created using computer-generated images. The FoV is, however, rather limited in its use for existing (legacy) content, achieving between 36 to 90 degrees ( ^{\circ} ) field, depending on the distance from the screen. This paper seeks to improve this FoV limitation by proposing computer vision techniques to extend such legacy content to the peripheral (extrafoveal) vision without changing the original creative intent or damaging the viewer's experience. A new methodology is also proposed for performing user tests in order to evaluate the quality of the experience and confirm that the sense of immersion has been increased. This paper thus presents: i) an algorithm to spatially extend- the video based on human vision characteristics, ii) its subjective results compared to state-of-the-art techniques, iii) the protocol required to evaluate the quality of the experience (QoE), and iv) the results of the user tests.
Auteurs: Laura Turban;Fabrice Urban;Philippe Guillotel;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1520 - 1533
Editeur: IEEE
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