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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 05-2017 trié par par titre, page: 8
» No-Reference and Robust Image Sharpness Evaluation Based on Multiscale Spatial and Spectral Features
Résumé:
The human visual system exhibits multiscale characteristic when perceiving visual scenes. The hierarchical structures of an image are contained in its scale space representation, in which the image can be portrayed by a series of increasingly smoothed images. Inspired by this, this paper presents a no-reference and robust image sharpness evaluation (RISE) method by learning multiscale features extracted in both the spatial and spectral domains. For an image, the scale space is first built. Then sharpness-aware features are extracted in gradient domain and singular value decomposition domain, respectively. In order to take into account the impact of viewing distance on image quality, the input image is also down-sampled by several times, and the DCT-domain entropies are calculated as quality features. Finally, all features are utilized to learn a support vector regression model for sharpness prediction. Extensive experiments are conducted on four synthetically and two real blurred image databases. The experimental results demonstrate that the proposed RISE metric is superior to the relevant state-of-the-art methods for evaluating both synthetic and real blurring. Furthermore, the proposed metric is robust, which means that it has very good generalization ability.
Auteurs: Leida Li;Wenhan Xia;Weisi Lin;Yuming Fang;Shiqi Wang;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 05.-2017, volume: 19, issue:5, pages: 1030 - 1040
Editeur: IEEE
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» Non-Invasive Stimulation-Based Tactile Sensation for Upper-Extremity Prosthesis: A Review
Résumé:
An ideal hand prosthesis should provide satisfying functionality based on reliable decoding of the user’s intentions and deliver tactile feedback in a natural manner. The absence of tactile feedback impedes the functionality and efficiency of dexterous hand prostheses, which leads to a high rejection rate from prostheses users. Thus, it is expected that integration of tactile feedback with hand prostheses will improve the manipulation performance and enhance perceptual embodiment for users. This paper reviews the state-of-the-art of non-invasive stimulation-based tactile sensation for upper-extremity prostheses, from the physiology of the human skin, to tactile sensing techniques, non-invasive tactile stimulation, and an emphasis on electrotactile feedback. The paper concludes with a detailed discussion of recent applications, challenging issues, and future developments.
Auteurs: Kairu Li;Yinfeng Fang;Yu Zhou;Honghai Liu;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2625 - 2635
Editeur: IEEE
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» Non-Iterative Enhanced SDP Relaxations for Optimal Scheduling of Distributed Energy Storage in Distribution Systems
Résumé:
Convexification of an optimal scheduling algorithm for distributed energy storage (DES) in radial distribution systems with high penetration of photovoltaic resources is studied. The AC power flow equalities are taken into account as constraints in the optimization model. Different from the typical optimal power flow problem, the objective function of a DES optimal scheduling (DESOS) problem varies with changing operational requirements. In this paper, three frequently-used objective functions are considered for the DESOS problem. Two of them are monotonic over the feasible set while the third is not. An illustrative example elucidates that the descent direction of a chosen objective function significantly impacts the efficiency of the second-order cone programming (SOCP) relaxation for the DESOS problem. To obtain tighter semidefinite programming (SDP) relaxations for the DESOS cases where the SOCP relaxation is not exact, this paper looks for computationally efficient convex constraints that can approximate the rank-1 constraint in the non-iterative framework. The designed non-iterative enhanced SDP relaxations are compared in terms of tightness of convexification for the DESOS problems considering the three objective functions independently. The comparison is performed on several radial IEEE test systems and a real world distribution feeder.
Auteurs: Qifeng Li;Vijay Vittal;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1721 - 1732
Editeur: IEEE
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» Noncoherent Short Packet Detection and Decoding for Scatter Radio Sensor Networking
Résumé:
Scatter radio, i.e., communication by means of reflection, has been recently proposed as a promising technology for low-power wireless sensor networks (WSNs). Specifically, this paper offers noncoherent receivers in scatter radio frequency-shift keying, for either channel-coded or uncoded scatter radio reception, in order to eliminate the need for training bits of coherent schemes (for channel estimation) at the packet preamble. Noncoherent symbol-by-symbol and sequence detectors based on hybrid composite hypothesis test (HCHT) and generalized likelihood-ratio test, for the uncoded case and noncoherent decoders based on HCHT, for small block-length channel codes, are derived. Performance comparison under Rician, Rayleigh, or no fading, taking into account fixed energy budget per packet is presented. It is shown that the performance gap between coherent and noncoherent reception depends on whether channel codes are employed, the fading conditions (e.g., Rayleigh versus Rician versus no fading), as well as the utilized coding interleaving depth; the choice of one coding scheme over the other depends on the wireless fading parameters and the design choice for extra diversity versus extra power gain. Finally, experimental outdoor results at 13-dBm transmission power corroborate the practicality of the proposed noncoherent detection and decoding techniques for scatter radio WSNs.
Auteurs: Panos N. Alevizos;Aggelos Bletsas;George N. Karystinos;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 2128 - 2140
Editeur: IEEE
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» Nonintrusive Power Measurement Method With Phase Detection for Low-Cost Smart Meters
Résumé:
This paper describes a nonintrusive power measurement method that is suitable for a new type of low-cost and easy-to-install smart meters in measuring current and power from parallel electric cables based on noncontact magnetic flux and identifying the power consumption of each phase. By placing noncontact magnetic flux sensors close to the parallel electric cables that carry electric currents, a method for providing flux-to-current conversion and reducing mutual coupling effects among these cables is introduced. By using the mains voltage of the electronic control circuit as a reference, a new and simple method for accurately differentiating the phase currents and power in the cables is proposed. The proposed method has been verified with practical power measurements with reasonable accuracy for this specific application.
Auteurs: Haoyuan Yang;Shu-Yuen Ron Hui;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3962 - 3969
Editeur: IEEE
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» Noninvasive Brain Stimulation Using Strong-Coupling Effect of Resonant Magnetics
Résumé:
This paper presents a novel noninvasive electromagnetic brain stimulation system, namely the transcranial magnetic stimulation (TMS), via strongly coupled magnetic resonances, which is used to improve treatment effects, enrich treatment means, and increase energy utilizations. To achieve expected stimulation effects, the conventional TMS system normally needs strict requirements for the power supply and the circuit. Inevitably, it not only deteriorates the implementability and flexibility of the noninvasive electromagnetic brain stimulation, but also increases the manufacture cost and energy consumption, thus significantly impeding the popularization of TMS technologies. Hence, a novel TMS system is proposed by utilizing the magnetic resonant coupling (MRC) mechanism, aiming to offer a brand new way to fulfill expected stimulation effects. By comparing with conventional TMS systems, the proposed system can effectively increase the strength so as to improve the stimulation depth, enhance the focality so as to prevent from impacting on nonfocal zones, and reduce the requirement on the power and frequency so as to promote the popularization of noninvasive electromagnetic treatments. In this paper, both simulation and experimental results are provided to verify the feasibility and superiority of the proposed MRC-based TMS system.
Auteurs: Bin Deng;Shuai Li;Bin Li;Jiang Wang;Zhen Zhang;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 9
Editeur: IEEE
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» Nonlinear Analytical Model of Eccentric Synchronous Reluctance Machines Considering the Iron Saturation and Slotting Effect
Résumé:
This paper deals with an improved analytical model of synchronous reluctance (REL) machine considering rotor eccentricity. This model considers the magnetic saturation in the iron parts of both the stator and the rotor. This saturation results from the actual B–H characteristic of the iron. In addition, the slotting effect is considered in the analytical model. The unbalanced magnetic force (UMF) on the rotor is accurately estimated. Furthermore, the impact on the estimated UMF due to the slotting effect and the magnetic saturation is studied. Both static and dynamic eccentricity cases are considered. As an example, a four-pole 36-slot REL motor with three flux-barriers per rotor pole is considered. Experimental measurements confirm the results achieved by means of both finite-element analysis and the improved analytical model.
Auteurs: Hanafy Mahmoud;Nicola Bianchi;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2007 - 2015
Editeur: IEEE
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» Nonlinear Model Predictive Control for Thermal Management in Plug-in Hybrid Electric Vehicles
Résumé:
A nonlinear model predictive control (NMPC) for the thermal management (TM) of plug-in hybrid electric vehicles (PHEVs) is presented. TM in PHEVs is crucial to ensure high components’ performance and durability in all possible climate scenarios. A drawback of accurate TM solutions is the higher electrical consumption due to the increasing number of low-voltage actuators used in the cooling circuits. Hence, more complex control strategies are needed for minimizing components’ thermal stress and, at the same time, electrical consumption. In this context, NMPC proves to be a powerful method for achieving multiple objectives in multiple input multiple output systems. This paper proposes an NMPC for the TM of the high-voltage battery and the power electronics cooling circuit in a PHEV. It distinguishes itself from the previously NMPC reported methods in the automotive sector by the complexity of its controlled plant, which is highly nonlinear and controlled by numerous variables. The implemented model of the plant, which is based on experimental data and multidomain physical equations, has been validated using six different driving cycles logged in a real vehicle, obtaining a maximum error, in comparison with the real temperatures of 2  $^circ$C. For one of the six cycles, an NMPC software-in-the loop (SIL) is presented, where the models inside the controller and for the controlled plant are the same. This simulation is compared with the finite-state machine-based strategy performed in the real vehicle. The results show that NMPC keeps the battery at healthier temperatures and reduces the cooling electrical consumption by more than 5%. In terms of the objective function, which is an accumulated and weighted sum of the two goals, this improvement amounts to 30%. Finally, the online SIL presented in this pap- r suggests that the used optimizer is fast enough for a future implementation in the vehicle.
Auteurs: Jorge Lopez-Sanz;Carlos Ocampo-Martinez;Jesus Alvarez-Florez;Manuel Moreno-Eguilaz;Rafael Ruiz-Mansilla;Julian Kalmus;Manuel Gräeber;Gerhard Lux;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 3632 - 3644
Editeur: IEEE
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» Nonlinear Observer for Temperatures and Emissivities in a Strip Annealing Furnace
Résumé:
The annealing process plays an important role for the product quality of steel strips. To achieve a high product quality, an accurate temperature control is essential, which typically requires information about the temperature evolution inside the strip annealing furnace. However, usually only a few temperatures at discrete points in the furnace can be measured. Therefore, this paper proposes an extended Kalman filter and an ad-hoc adaptive estimator for the furnace temperatures. Moreover, both observers also estimate the inexactly known strip emissivity. The observers are validated by means of measurement data from an industrial furnace. This validation demonstrates the reliability and accuracy of the ad-hoc adaptive estimator.
Auteurs: Stephan Strommer;Martin Niederer;Andreas Steinboeck;Lukas Jadachowski;Andreas Kugi;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2578 - 2586
Editeur: IEEE
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» Nonlinear Radar for Finding RF Electronics: System Design and Recent Advancements
Résumé:
An extensive review of nonlinear radar systems is performed. Emphasis is placed on designs relevant to detecting RF electronics that were not intentionally manufactured as visible radar targets. The state of the art in nonlinear radar is conveyed by presenting high-level system architecture, explaining the rationale behind design decisions pertaining to that architecture, and listing the specifications that nonlinear radar designers have achieved. The authors’ recent advancements in nonlinear radar technology are summarized.
Auteurs: Gregory J. Mazzaro;Anthony F. Martone;Kenneth I. Ranney;Ram M. Narayanan;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1716 - 1726
Editeur: IEEE
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» Nonvolatile Resistance Effect Modulated by Pulse With Laser Observed in Nano-Carbon Film
Résumé:
A nonvolatile resistance effect modulated by pulse with laser was observed in nano-carbon oxide semiconductor structures. By applying a short voltage pulse with laser illumination, the lateral resistance of the structure can be permanently changed. The resistance change ratio can reach up to 65%. More interestingly, the effect shows polarity under different illumination spot and voltage directions. This phenomenon is attributed to the trapping effect of laser-stimulated electrons in be useful for the development of laser-and pulse-modulated resistors, switches, and sensors.
Auteurs: Z. K. Gan;P. Q. Zhou;X. Huang;C. L. Mei;J. Q. Hu;H. Wang;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 560 - 563
Editeur: IEEE
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» Not Happy? Move On
Résumé:
Over the past 50 years, a number of papers have been published in an attempt to determine what factors make an employee happy and satisfied versus those factors that lead to dissatisfaction and poor performance. Perhaps the two most prominent authors are Frederick Hertzberg and Abraham Maslow. While Maslow first published his hierarchy of needs, Herzberg extended that work, developing his own needs model. The two models compare quite closely, with minor differences in the words used to define the separate levels of an individual's feeling of satisfaction on the job.
Auteurs: Raymond E. Floyd;
Apparue dans: IEEE Potentials
Date publication: 05.-2017, volume: 36, issue:3, pages: 23 - 25
Editeur: IEEE
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» Novel Chest Compression Depth Measurement Sensor Using IR-UWB for Improving Quality of Cardiopulmonary Resuscitation
Résumé:
Cardiac arrest is a common cause of death in the world. Immediate high-quality cardiopulmonary resuscitation (CPR) improves the chances of survival of cardiac arrest patients. In particular, maintaining an adequate chest compression depth (CCD) during CPR is a key determinant for survival from cardiac arrest. If it is possible to measure the CCD accurately during CPR, we could increase the survival rate of patients by improving the quality of CPR. This work proposes a new sensor that could measure the CCD accurately during CPR. Compared with existing sensors that utilize pressures or accelerometers, the proposed sensor employs distance measurements based on the time-difference-of-arrival using impulse-radio ultra-wideband (IR-UWB). The method directly measures the CCD using two antennas at the chest and at the back, thereby eliminating the distance error under CPR environments, which is present in existing accelerometer sensors. The designed sensor has an 0.08 mm resolution, and an inaccuracy of less than ±1.25 mm, within a range of 0-40 cm. This sensor was applied to a CPR manikin to measure the CCD in an environment where CPR is performed.
Auteurs: Yeomyung Kim;Byung Gyu Yu;Je Hyeok Oh;Tae Wook Kim;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3174 - 3183
Editeur: IEEE
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» Novel Dynamic Voltage Support Capability of Photovoltaic Systems for Improvement of Short-Term Voltage Stability in Power Systems
Résumé:
The large integration of photovoltaic (PV) power generation systems into power systems causes deterioration in power system stability. In our previous work, we showed that reactive power control using the inverters of PV systems, known as dynamic voltage support (DVS) capability, is a promising approach to improve the short-term voltage stability in power systems. In this paper, we propose a novel DVS capability as a function of PV inverters. In contrast to the conventional DVS capability, the proposed method uses both active and reactive power injection to improve the short-term voltage stability. Numerical examples show that the proposed DVS capability further improves the short-term voltage stability compared with the conventional DVS capability. Furthermore, the proposed method can alleviate a frequency drop after a fault caused by interruption in PV systems.
Auteurs: Kenichi Kawabe;Yutaka Ota;Akihiko Yokoyama;Kazuyuki Tanaka;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1796 - 1804
Editeur: IEEE
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» Novel Fast Coherent Detection Algorithm for Radar Maneuvering Target With Jerk Motion
Résumé:
The detection performance of radar maneuvering target with jerk motion is affected by the range migration (RM) and Doppler frequency migration (DFM). To address these problems, a fast algorithm without searching target's motion parameters is proposed. In this algorithm, the second-order keystone transform is first applied to eliminate the quadratic coupling between the range frequency and slow time. Then, by employing a new defined symmetric autocorrelation function, scaled Fourier transform, and inverse fast Fourier transform, the target's initial range and velocity are estimated. With these two estimates, the azimuth echoes along the target's trajectory, which can be modeled as a cubic phase signal (CPS), are extracted. Thereafter, the target's radial acceleration and jerk are estimated by approaches for parameters estimation of the CPS. Finally, by constructing a compensation function, the RM and DFM are compensated simultaneously, followed by the coherent integration and target detection. Comparisons with other representative algorithms in computational cost, motion parameter estimation performance, and detection ability indicate that the proposed algorithm can achieve a good balance between the computational cost and detection ability. The simulation and raw data processing results demonstrate the effectiveness of the proposed algorithm.
Auteurs: Jiancheng Zhang;Tao Su;Jibin Zheng;Xuehui He;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1792 - 1803
Editeur: IEEE
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» Novel Folded-KES Architecture for High-Speed and Area-Efficient BCH Decoders
Résumé:
In this brief, we present a novel folding technique for high-speed and low-cost Bose–Chaudhuri–Hocquenghem (BCH) decoders. In the conventional BCH decoder, the critical path lies on the Galois-field (GF) multiplier of the key equation solver, where the speedup of the critical path is very difficult due to a significant area increase. In the proposed work, the regularly structured GF multiplier is introduced to be efficiently folded to reduce the complexity and the critical delay. Moreover, the conventional global folding scheme can be applied to further reduce the hardware costs. The implementation results show that the proposed folding scheme enhances the area efficiency by 1.73 and 1.9 times in the Digital Video Broadcasting–Satellite–Second Generation system and the storage controller, respectively.
Auteurs: Byeonggil Park;Seungyong An;Jongsun Park;Youngjoo Lee;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 535 - 539
Editeur: IEEE
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» Novel Matching Network and Its Application to Quad-Channel Diplexers
Résumé:
This letter reports a new kind of matching network for quad-channel diplexers. The matching network is comprised by some open- and short-circuited transmission lines, which can be chosen based on the design graph. The impact of loading resonators on the network is discussed. The diplexer can be easily realized by the combination of different bandpass filters without complicated tuning. To illustrate the concept, one quad-channel diplexer is designed, fabricated, and measured. Simulated and measured results are found to be in good agreement with each other.
Auteurs: Qiang Shao;Fu-Chang Chen;Jian-Feng Qian;Jie-Ming Qiu;Qing-Xin Chu;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 452 - 454
Editeur: IEEE
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» Novel Methodology for Selecting Representative Operating Points for the TNEP
Résumé:
As part of transmission network expansion planning (TNEP), a technical and economical assessment of several planning alternatives must be performed in order to ensure fulfillment of the network security criteria and to estimate the alternatives’ expected operating costs. This task requires performing load flow calculations for different operating points (OPs) of the power system. Due to the high computational burden, considering all possible OPs is simply not possible. As a consequence, only a set of representative OPs is usually taken into account. Most works in the TNEP focus on issues related to optimization algorithms and modeling, neglecting the selection process of the representative OPs. Furthermore, most works only consider a few OPs, providing little or no insight about the criteria used in the selection process or about the error made when evaluating planning alternatives using a limited number of OPs. In this work, a novel methodology for selecting representative OPs to consider within the TNEP is presented. The proposal pays special attention to critical situations, where the network security may be endangered. Furthermore, the methodology allows quantifying the error made when evaluating network operation using a limited number of representative OPs.
Auteurs: Ricardo Alvarez;Albert Moser;Claudia Andrea Rahmann;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2234 - 2242
Editeur: IEEE
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» Novel Microfluidically Tunable Differential Dual-Mode Patch Filter
Résumé:
This letter presents a novel microfluidcally tunable differential bandpass filter (BPF) with precisely controlled passband frequency. The frequency tunability of the filter is realized by inserting microfluidic channels, which can be filled with high dielectric constant fluid, i.e., distilled water, between the dual-mode patch resonator and the ground plane. Meanwhile, the frequency-tuning capability of the channels highly depends on the E-field distributions of the two modes on the patch. By properly choosing the orientations and spaces of the channels, the two-mode resonant frequencies can be simultaneously shifted up/down, and thus the frequency tuning states of the differential-mode passband can be precisely controlled with proper water-filling sequence. For demonstration, the proposed BPF is designed and fabricated. The simulated and measured results are presented, showing good agreement.
Auteurs: Wen-Jun Zhou;Hui Tang;Jian-Xin Chen;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 461 - 463
Editeur: IEEE
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» Novel Multidimensional Models of Opinion Dynamics in Social Networks
Résumé:
Unlike many complex networks studied in the literature, social networks rarely exhibit unanimous behavior, or consensus. This requires a development of mathematical models that are sufficiently simple to be examined and capture, at the same time, the complex behavior of real social groups, where opinions and actions related to them may form clusters of different size. One such model, proposed by Friedkin and Johnsen, extends the idea of conventional consensus algorithm (also referred to as the iterative opinion pooling) to take into account the actors’ prejudices, caused by some exogenous factors and leading to disagreement in the final opinions. In this paper, we offer a novel multidimensional extension, describing the evolution of the agents’ opinions on several topics. Unlike the existing models, these topics are interdependent, and hence the opinions being formed on these topics are also mutually dependent. We rigorously examine stability properties of the proposed model, in particular, convergence of the agents’ opinions. Although our model assumes synchronous communication among the agents, we show that the same final opinions may be reached “on average” via asynchronous gossip-based protocols.
Auteurs: Sergey E. Parsegov;Anton V. Proskurnikov;Roberto Tempo;Noah E. Friedkin;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2270 - 2285
Editeur: IEEE
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» Novel Radiation-Hardened-by-Design (RHBD) 12T Memory Cell for Aerospace Applications in Nanoscale CMOS Technology
Résumé:
In this paper, a novel radiation-hardened-by-design (RHBD) 12T memory cell is proposed to tolerate single node upset and multiple-node upset based on upset physical mechanism behind soft errors together with reasonable layout-topology. The verification results obtained confirm that the proposed 12T cell can provide a good radiation robustness. Compared with 13T cell, the increased area, power, read/write access time overheads of the proposed 12T cell are −18.9%, −23.8%, and 171.6%/−50.0%, respectively. Moreover, its hold static noise margin is 986.2 mV which is higher than that of 13T cell. This means that the proposed 12T cell also has higher stability when it provides fault tolerance capability.
Auteurs: Jing Guo;Lei Zhu;Wenyi Liu;Hai Huang;Shanshan Liu;Tianqi Wang;Liyi Xiao;Zhigang Mao;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1593 - 1600
Editeur: IEEE
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» Novel Summation Inequalities and Their Applications to Stability Analysis for Systems With Time-Varying Delay
Résumé:
The inequality technique plays an important role in stability analysis for time-delay systems. This technical note presents a new sequence of novel summation inequalities by introducing some free matrices, which includes the newly-developed Wirtinger-based and free-matrix-based summation inequalities as special cases. Moreover, the idea can be easily extended to the multiple-summation-inequality case. Based on the proposed inequalities, relaxed stability conditions are obtained for systems with time-varying delay. Numerical examples are given to demonstrate the effectiveness of the proposed approach.
Auteurs: Jun Chen;Shengyuan Xu;Xianglei Jia;Baoyong Zhang;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2470 - 2475
Editeur: IEEE
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» Novel Two-Phase Approach for Process Optimization of Customer Collaborative Design Based on Fuzzy-QFD and DSM
Résumé:
In response to fast-growing and rapidly changing global markets, launching new products faster than competitors does not only assist enterprises in acquiring a larger market share, but also in reducing development lead time. However, owing to the intrinsically uncertain properties of new product development management, manufacturing companies often struggle with the dilemma of whether to increase product variety or control manufacturing complexity. This paper proposes a novel two-phase method to assist an enterprise in achieving a customer collaborative product design. In the first phase, quality function deployment, which is based on fuzzy multicriteria decision making and suppliers’ budget constraints, is presented to maximize customers’ satisfaction. In the second phase, an effective approach is proposed to determine the appropriate sequence of several coupled activities with the minimum total feedback time in a design structure matrix. Finally, a real case is used to illustrate the overall applicability of the approach. The optimization results show the effectiveness and superiority of the proposed method over other reported methods in the literature.
Auteurs: Aijun Liu;Hesuan Hu;Xiao Zhang;Deming Lei;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 05.-2017, volume: 64, issue:2, pages: 193 - 207
Editeur: IEEE
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» Numerical Investigation of an UWB Localization Technique for Unmanned Aerial Vehicles in Outdoor Scenarios
Résumé:
In this paper, the numerical investigation of an ultra wideband (UWB) localization technique suitable for the tracking and control of an unmanned aerial vehicle (UAV) in a specific outdoor scenario is presented. A set of UWB nodes are located on a moving/still ground station (GS) and interrogate an UWB node placed on the UAV that is flying in front of the GS. The distances between the GS-nodes and the UAV-node are estimated through a conventional two-way time-of-flight ranging method, one at a time, and then used in a multilateration algorithm. Due to the unavoidable relative motion between the UAV and the GS, the above distances are actually measured for different UAV-GS relative positions, and then, the UAV localization performance deteriorates as a function of the UAV-GS relative speed and the ranging-method processing time. An approach is here proposed to mitigate the above adverse effect, by exploiting an estimate of the UAV-GS relative speed along the GS forward direction. A preliminary numerical analysis is used to show that a decimeter order localization accuracy can be obtained for a tridimensional localization process.
Auteurs: Fabrizio Lazzari;Alice Buffi;Paolo Nepa;Sandro Lazzari;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2896 - 2903
Editeur: IEEE
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» Numerical Manipulation of Digital Holograms for 3-D Imaging and Display: An Overview
Résumé:
In the last two decades, thanks to the considerable technological development of solid-state sensors, digital holography (DH) has gained credits as the elective imaging technique for applications in various research fields, e.g., material science, biotechnology, as well as a diagnostic tool for applications at lab-on-a-chip scale. However, since its beginning, the intrinsic coherent nature of holography made 3-D imaging and display one of its preferred applications. Still today, several research groups around the world are working to develop novel numerical solutions in the framework of DH-based 3-D imaging and display technology. In this paper, we report an overview of the most important contributions given to this field over the last years.
Auteurs: P. Memmolo;V. Bianco;M. Paturzo;P. Ferraro;
Apparue dans: Proceedings of the IEEE
Date publication: 05.-2017, volume: 105, issue:5, pages: 892 - 905
Editeur: IEEE
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» Numerical Model of an Injection-Locked Wideband Frequency Modulator for Polar Transmitters
Résumé:
We present a numerical model of a wideband injection-locked frequency modulator used in a polar transmitter for 3G cellular radio application. At the heart of the system is a self-injection-locked oscillator with a programmable linear tuning range of up to 200 MHz at 4-GHz oscillation frequency. The oscillator is injection locked to a time-delayed version of its resonating voltage, and its frequency is modulated by manipulating the phase and amplitude of the injected current. The model is used to study the feasibility of the proposed system by analyzing the impact of various impairments in the auxiliary injection loop on the system performance. The model is written in MATLAB/SIMULINK, and the simulation output is analyzed by a vector signal analyzer in terms of 3GPP specifications. Based on the simulation results, key specifications for individual blocks in the system are determined. The key benefits of the presented modeling methodology are simplicity, efficiency, and portability.
Auteurs: Imran Bashir;Robert Bogdan Staszewski;Poras T. Balsara;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1914 - 1920
Editeur: IEEE
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» Numerical Simulation of Vacuum Arc Behavior Considering Action of Adjacent Phases in Vacuum Circuit Breakers
Résumé:
In the interrupting process of a three-phase vacuum interrupter, there exists a transverse magnetic field (TMF) in the interelectrode region, which is produced by adjacent phases. The deflection of the vacuum arc caused by TMF will affect the interrupting process of vacuum circuit breakers. In this paper, the vacuum arc characteristics considering the action of TMF produced by adjacent phases is simulated based on a steady 2-D asymmetrical magnetohydrodynamic model. The simulation results show that the vacuum arc will swing around and is especially obvious at the smaller current moments near current-zero during one ac half-cycle, because of the changed direction of TMF produced by adjacent phases. This kind of swing phenomena can also be observed in the electrode erosion of unsuccessful interruption. At the moments near current-zero, axial magnetic field is relatively weaker, while TMF generated by adjacent phases is relatively stronger, therefore, the offset phenomenon of plasma parameters is more significant. Compared with smaller diameter electrode arc, larger diameter electrode has larger arc deflection distance, while its value of plasma parameters is much smaller.
Auteurs: Lijun Wang;Kang Qin;Lilan Hu;Xiao Zhang;Shenli Jia;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 859 - 867
Editeur: IEEE
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» Object-Based Analysis and Fusion of Optical and SAR Satellite Data for Dwelling Detection in Refugee Camps
Résumé:
This study investigates the potential of very high spatial resolution (VHSR) optical WorldView-2 (WV-2) and single-polarized TerraSAR-X (TSX) synthetic aperture radar (SAR) satellite data for an automated detection of different dwelling types in a refugee camp by means of object-based image analysis (OBIA). First, the optical data and SAR data are analyzed independently, and then a fusion of both data sets is performed applying two different approaches: 1) an overlay operation-based procedure integrating the independent results of the optical- and SAR-based dwelling detection, and 2) a feature-based analysis approach taking advantage of the conjoint analysis of both data sets. The results of the single-sensor and the data fusion approaches are evaluated in detail on the basis of object-based and area-based accuracy assessments. Advantages and limitations of the analysis approaches are discussed. The accuracy rates reveal that the use of optical satellite data shows promising results regardless of the dwelling material, while the SAR data are suitable for the detection of metal sheet dwellings only. In complex camp areas, with closely spaced containers, the results of the independent analyses can be improved significantly by the proposed fusion approaches. The combination of SAR and optical data allows for the separation of contiguous dwellings in cases this was not possible by the optical sensor information
Auteurs: Kristin Spröhnle;Eva-Maria Fuchs;Patrick Aravena Pelizari;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1780 - 1791
Editeur: IEEE
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» Observer-Based Controllers for Max-Plus Linear Systems
Résumé:
Max-plus algebra is a suitable algebraic setting to model discrete event systems involving synchronization and delay phenomena which are often found in transportation networks, communications systems, and manufacturing systems. One way of controlling this kind of systems consists in choosing the dates of input events in order to achieve the desired performances, e.g., to obtain output events in order to respect given dates. This kind of control is optimal, according to a just-in-time criterion, if the input-event dates are delayed as much as possible while ensuring the output events to occur before a desired reference date. This paper presents the observer-based controller for max-plus linear systems where only estimations of system states are available for the controller. As in the classical sense, this is a state-feedback control problem, which is solved in two steps: first, an observer computes an estimation of the state by using the input and the output measurements, then, this estimated state is used to compute the state-feedback control action. As a main result, it is shown that the optimal solution of this observer-based control problem leads to a greater control input than the one obtained with the output feedback strategy. A high throughput screening example in drug discovery illustrates this main result by showing that the scheduling obtained from the observer-based controller is better than the scheduling obtained from the output feedback controller.
Auteurs: Laurent Hardouin;Ying Shang;Carlos Andrey Maia;Bertrand Cottenceau;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2153 - 2165
Editeur: IEEE
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» Observer-Based Human Knee Stiffness Estimation
Résumé:
Objective: We consider the problem of stiffness estimation for the human knee joint during motion in the sagittal plane. Methods: The new stiffness estimator uses a nonlinear reduced-order biomechanical model and a body sensor network (BSN). The developed model is based on a two-dimensional knee kinematics approach to calculate the angle-dependent lever arms and the torques of the muscle-tendon-complex. To minimize errors in the knee stiffness estimation procedure that result from model uncertainties, a nonlinear observer is developed. The observer uses the electromyogram (EMG) of involved muscles as input signals and the segmental orientation as the output signal to correct the observer-internal states. Because of dominating model nonlinearities and nonsmoothness of the corresponding nonlinear functions, an unscented Kalman filter is designed to compute and update the observer feedback (Kalman) gain matrix. Results: The observer-based stiffness estimation algorithm is subsequently evaluated in simulations and in a test bench, specifically designed to provide robotic movement support for the human knee joint. Conclusion: In silico and experimental validation underline the good performance of the knee stiffness estimation even in the cases of a knee stiffening due to antagonistic coactivation. Significance: We have shown the principle function of an observer-based approach to knee stiffness estimation that employs EMG signals and segmental orientation provided by our own IPANEMA BSN. The presented approach makes realtime, model-based estimation of knee stiffness with minimal instrumentation possible.
Auteurs: Berno J. E. Misgeld;Markus Lüken;Robert Riener;Steffen Leonhardt;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 1033 - 1044
Editeur: IEEE
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» Observing Sea/Ice Transition Using Radar Images Generated From TechDemoSat-1 Delay Doppler Maps
Résumé:
In this letter, Global Navigation Satellite System Reflectometry (GNSS-R) delay Doppler maps (DDMs) acquired by the U.K. TechDemoSat-1 (TDS-1) mission are analyzed to identify sea ice infesting waters in circumpolar areas. First, the sensitivity of actual DDM to sea ice is investigated using reference information provided by a Sentinel-1 synthetic aperture radar imagery and a Special Sensor Microwave/Imager based sea–ice concentration map. Then, a new product is proposed that consists of normalized radar cross section measurements derived from actual DDMs and arranged in gridded format. This product is shown to provide spatial information on the sea ice transition that cannot be obtained exploiting the conventional DDM product. Hence, this new product can be used to improve/complement conventional remote sensing techniques for sea ice observation.
Auteurs: Domenico Schiavulli;Frédéric Frappart;Guillaume Ramillien;José Darrozes;Ferdinando Nunziata;Maurizio Migliaccio;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 734 - 738
Editeur: IEEE
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» Observing the Permanent-Magnet Temperature of Synchronous Motors Based on Electrical Fundamental Wave Model Quantities
Résumé:
Estimating the magnet temperature of permanent-magnet synchronous motors on a model basis is the key for both the highest device utilization and preventing irreversible demagnetization. Using an exact flux linkage observer in the fundamental wave domain is an elegant way to indirectly retrieve the magnet temperature without requiring any additional sensors or signal injection. This contribution addresses several important issues for the real-world applicability of a permanent magnet temperature observer: thermal expansion affecting the radial air gap thickness, operation at low speeds or even standstill, and estimating the fundamental content of the motor's terminal voltage within one switching cycle. The proposed observer is comprehensively validated in the entire electrical and thermal operation range achieving a satisfying worst case error less than 10 K.
Auteurs: Oliver Wallscheid;Andreas Specht;Joachim Böcker;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3921 - 3929
Editeur: IEEE
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» Occluded Object Detection in High-Resolution Remote Sensing Images Using Partial Configuration Object Model
Résumé:
Deformable-part-based model (DPM) has shown great success in object detection in recent years. However, its performance will degrade on partially occluded objects and is even worse on largely occluded objects in real remote sensing applications. To address this problem, a novel partial configuration object model (PCM) is developed in this paper. Compared to conventional single-layer DPMs, an extra partial configuration layer, which is composed of partial configurations defined according to possible occlusion patterns, is introduced in PCM to block the transmission of occlusion impact. During detection, each hypothesis from a partial configuration layer will infer the entire object based on spatial interrelationship and final detection results are obtained from the fusion of these possible entire objects using a weighted continuous clustering method. As PCM makes a better compromise between the deformation modeling flexibility of small parts and the discriminative shape-capturing capability of large DPM, its performance on occluded object detection will be improved. Moreover, occlusion states of detected objects can be inferred with the intermediate results of our model. Experimental results on multiple high-resolution remote sensing image datasets demonstrate the effectiveness of the proposed model.
Auteurs: Shaohua Qiu;Gongjian Wen;Yaxiang Fan;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1909 - 1925
Editeur: IEEE
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» OFDM Based Multi-Node Transmission in the Presence of Phase Noises for Small Cell Backhaul
Résumé:
In this letter, the phase noise (PN) effect on orthogonal frequency division multiplexing based multi-node transmission for small cell backhaul is studied. Since each transmitter is equipped with an independent oscillator, the received signals are corrupted by all of these independent PNs (plus the PN at the receiver), which renders the conventional PN compensation schemes at the receiver ineffective. In this letter, a PN compensation scheme for multi-node transmission is proposed, which can effectively mitigate the effect of the multiple PNs.
Auteurs: Xiaoming Chen;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1207 - 1210
Editeur: IEEE
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» Off-the-Grid Compressive Time Delay Estimation via Manifold-Based Optimization
Résumé:
The time delay estimation (TDE) of some known waveforms from sampled data is of great interest in the area of signal processing, e.g., wireless communication, radar, and sonar. Classical algorithms, such as matched filters, multiple signal classification always work under the Nyquist sampling rate determined by the bandwidth of the waveform. With the assumption of sparsity, the novel compressive sensing (CS)-based algorithms are proposed in recent studies, which theoretically reduce the sampling rate but preserve the same accuracy. Yet these novel algorithms often suffer from the-so-called off-the-grid issue (or basis mismatch) and do not perform as well as expectations. This letter proposes a manifold-based optimization strategy to improve the CS-based TDE algorithms in order to solve this issue and improve the estimation accuracy and the resolution. The proposed algorithm not only achieve a much higher accuracy but also works under a much lower sampling rate compared with the state-of-the-art CS-based algorithms.
Auteurs: Wei Zhang;Feng Yu;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 983 - 986
Editeur: IEEE
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» On Connectivity and Robustness in Random Intersection Graphs
Résumé:
Random intersection graphs have received much attention recently and been used in a wide range of applications ranging from key predistribution in wireless sensor networks to modeling social networks. For these graphs, each node is equipped with a set of objects in a random manner, and two nodes have an undirected edge in between if they have at least one object in common. In this paper, we investigate connectivity and robustness in a general random intersection graph model. Specifically, we establish sharp asymptotic zero-one laws for $k$-connectivity and $k$-robustness, as well as the asymptotically exact probability of $k$-connectivity, for any positive integer $k$. The $k$ -connectivity property quantifies how resilient is the connectivity of a graph against node or edge failures, while $k$-robustness measures the effectiveness of local-information-based consensus algorithms (which do not use global graph topology information) in the presence of adversarial nodes. In addition to presenting the results under the general random intersection graph model, we consider two special cases of the general model, a binomial random intersection graph and a uniform random intersection graph, which both have numerous applications as well. For these two specialized graphs, we present asymptotically exact probabilities of $k$-connectivity and asymptotic zero-one laws for $k$-robustness.
Auteurs: Jun Zhao;Osman Yağan;Virgil Gligor;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2121 - 2136
Editeur: IEEE
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» On distance-adaptive routing and spectrum assignment in mesh elastic optical networks
Résumé:
The routing and spectrum assignment (RSA) problem has emerged as the key design and control problem in elastic optical networks. Distance-adaptive spectrum allocation exploits the tradeoff between spectrum width and reach to improve resource utilization by tailoring the modulation format to the level of impairments along the path. In this paper, we consider the distance-adaptive RSA (DA-RSA) problem with fixed alternate routing. We first show that the DA-RSA problem in networks of general topology is a special case of a well-studied multiprocessor scheduling problem. We then leverage insights from the scheduling theory to 1) present new results regarding the complexity of the DA-RSA problem and 2) build upon the list of scheduling concepts to develop a computationally efficient solution approach that is effective in utilizing the available spectrum resources.
Auteurs: Sahar Talebi;George N. Rouskas;
Apparue dans: IEEE/OSA Journal of Optical Communications and Networking
Date publication: 05.-2017, volume: 9, issue:5, pages: 456 - 465
Editeur: IEEE
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» On Emerging Family of Elliptic Curves to Secure Internet of Things: ECC Comes of Age
Résumé:
Lightweight Elliptic Curve Cryptography (ECC) is a critical component for constructing the security system of Internet of Things (IoT). In this paper, we define an emerging family of lightweight elliptic curves to meet the requirements on some resource-constrained devices. We present the design of a scalable, regular, and highly-optimized ECC library for both MICAz and Tmote Sky nodes, which supports both widely-used key exchange and signature schemes. Our parameterized implementation of elliptic curve group arithmetic supports pseudo-Mersenne prime fields at different security levels with two optimized-specific designs: the high-speed version (HS) and the memory-efficient (ME) version. The former design achieves record times for computation of cryptographic schemes at roughly $80sim 128$ -bit security levels, while the latter implementation only requires half of the code size of the current best implementation. We also describe our efforts to evaluate the energy consumption and harden our library against some basic side-channel attacks, e.g., timing attacks and simple power analysis (SPA) attacks.
Auteurs: Zhe Liu;Xinyi Huang;Zhi Hu;Muhammad Khurram Khan;Hwajeong Seo;Lu Zhou;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 05.-2017, volume: 14, issue:3, pages: 237 - 248
Editeur: IEEE
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» On Joint Pareto Frontier in Multiple Access and Relay Rate Regions With Rayleigh Fading
Résumé:
To meet the growing demand for wireless traffic, various types of relay and heterogeneous networks have received attention in the recent literature. This paper focuses on novel norm balancing algorithms based on cost-reward formulations on multiple access channels (MACs), and the results are extended to decode-and-forward (DF) relay systems. The achievable rates by different users in multiuser systems present an inherent tradeoff, which is formally known as Pareto efficiency. The analyses carried out in this paper show that any power allocation can be Pareto efficient in an MAC, provided certain conditions on the performance metric and decoding order. Based on the analysis, a novel method for efficient power allocation has been proposed to meet a target sum rate. The results have been explained in light of previous literature on polymatroid rate region and the requirement of rate vector equality. It is necessary to ensure and find the intersection of two polymatroids to operate the systems at a joint Pareto frontier of the relay channels. Two algorithms to test for the existence of the joint Pareto frontier have been proposed and compared.
Auteurs: Swagato Barman Roy;A. S. Madhukumar;Jingon Joung;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 3777 - 3786
Editeur: IEEE
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» On Low Complexity ML Decoder for Quaternion Orthogonal Designs
Résumé:
Quaternion orthogonal designs (QODs) provide an efficient way of constructing orthogonal space time polarization block codes to achieve larger transmit diversity gains without substantial increase in antenna dimensions. However, their optimal decoding remains a big challenge. This letter introduces an important constraint, which has not been emphasized before, for decoupled decoding of QODs and proposes a generalized low complexity maximum-likelihood decoder for QODs based on symmetric-paired designs. The main contribution of this letter is to explore the benefits of QODs for smaller as well as higher order designs without compromising system performance. Results show that the proposed decoder yields optimal decoupled decoding with remarkably low complexity. This letter also compares the performance of quaternion coordinate interleaved orthogonal designs (QCIODs), which provide full diversity, with proposed symmetric-paired designs and shows that proposed designs significantly outperform QCIODs.
Auteurs: Erum Mushtaq;Sajid Ali;Syed Ali Hassan;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1087 - 1090
Editeur: IEEE
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» On Market-Driven Hybrid-P2P Video Streaming
Résumé:
Consistent (pause-free) quality of service is required in peer-to-peer (P2P) video streaming systems. In this paper, we aim to eliminate the problem of playback pauses in such systems via the use of positive incentives for peers to contribute high upload rates. We model our problem as a market, where the market stakeholders consist of multiple content providers, advertisement providers, and network peers; the positive incentives for peers in the market are reduced advertisement (ad) viewing durations. From a system design perspective, one of our primary goals is to compute the market equilibria that include appropriate ad viewing durations, offering sufficient incentives for network peers to continue contributing. Our simulation-based studies demonstrate that we mitigate the “playback pause” problem for peers by up to 80% as compared to existing approaches, generate sufficient utility for advertisers to be part of the market, and enable content providers to achieve their desired utility by providing sufficient incentives for all peers to stay in the system without violating ad provider agreements.
Auteurs: Sung-Han Lin;Ranjan Pal;Bo-Chun Wang;Leana Golubchik;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 05.-2017, volume: 19, issue:5, pages: 984 - 998
Editeur: IEEE
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» On Measuring the Geographic Diversity of Internet Routes
Résumé:
Route diversity in networks is elemental for establishing reliable, high-capacity connections with appropriate security between endpoints. As for the Internet, route diversity has already been studied at both the autonomous system and router level topologies by means of graph theoretical disjoint paths. In this article we complement these approaches by proposing a method for measuring the diversity of Internet paths in a geographical sense. By leveraging the recent developments in IP geolocation we show how to map the paths discovered by traceroute into geographically equivalent classes. This allows us to identify the geographical footprints of the major transmission paths between end-hosts, and building on our observations, we propose a quantitative measure for geographical diversity of Internet routes between any two hosts.
Auteurs: Attila Csoma;Andras Gulyas;Laszlo Toka;
Apparue dans: IEEE Communications Magazine
Date publication: 05.-2017, volume: 55, issue:5, pages: 192 - 197
Editeur: IEEE
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» On Missing Tag Detection in Multiple-Group Multiple-Region RFID Systems
Résumé:
We formulate and study a missing tag detection problem arising in multiple-group, multiple-region radio frequency identification (RFID) systems, where a mobile reader needs to detect whether there is any missing event for each group of tags. The problem we tackle is to devise missing tag detection protocols with minimum execution time while guaranteeing the detection reliability requirement for each group. By leveraging the technique of Bloom filter, we develop a suite of three missing tag detection protocols, each decreasing the execution time compared to its predecessor by incorporating an improved version of the Bloom filter design and parameter tuning. By sequentially analyzing the developed protocols, we gradually iron out an optimum detection protocol that works in practice.
Auteurs: Jihong Yu;Lin Chen;Rongrong Zhang;Kehao Wang;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1371 - 1381
Editeur: IEEE
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» On Novel Methods for Characterizing the Arc/Contact Movement and Its Relation With the Current/Voltage in Low-Voltage Circuit Breaker
Résumé:
This paper presents a work that was aimed to develop methods along with test facilities for characterizing the arc/contact movement in low-voltage miniature circuit breaker which has a related current under 125 A, and to find its relation with the short-circuit current/voltage in the circuit. The method consists of: 1) the high-speed camera for obtaining the image of the arc or contact movement; 2) the data acquisition system that measures the current during the short-circuit break; and 3) the circuitry system that establishes the synchronization of the arc movement capturing and the current acquisition. In particular, two methods were developed for this purpose: one based on analog signal and the other based on digital signal. The experiment shows that the accuracy of the synchronization, dependent on the sampling rate of the high-speed camera, is about from tens of microseconds to hundreds of microseconds with both methods. The two methods have their own advantages and disadvantages, and they can be tailored to applications for the best performance.
Auteurs: Chunlei Li;Dong Wei;Bing Zhang;Jin Li;Wenjun Zhang;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 882 - 888
Editeur: IEEE
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» On Optimal Infrastructure Sharing Strategies in Mobile Radio Networks
Résumé:
The rapid evolution of mobile radio network technologies poses severe technical and economical challenges to mobile network operators (MNOs); on the economical side, the continuous roll-out of technology updates is highly expensive, which may lead to the extreme, where offering advanced mobile services becomes no longer affordable for MNOs which thus, are not incentivized to innovate. Mobile infrastructure sharing among MNOs becomes then an important building block to lower the required per-MNO investment cost involved in the technology roll-out and management phases. We focus on a radio access network (RAN) sharing situation where multiple MNOs with a consolidated network infrastructure coexist in a given set of geographical areas; the MNOs have then to decide if it is profitable to upgrade their RAN technology by deploying additional small-cell base stations and whether to share the investment (and the deployed infrastructure) of the new small-cells with other operators. We address such strategic problems by giving a mathematical framework for the RAN infrastructure sharing problem which returns the “best” infrastructure sharing strategies for operators (coalitions and network configuration) when varying techno-economic parameters such as the achievable throughput in different sharing configurations and the pricing models for the service offered to the users. The proposed formulation is then leveraged to analyze the impact of the aforementioned parameters/input in a realistic mobile network environment based on LTE technology.
Auteurs: Lorela Cano;Antonio Capone;Giuliana Carello;Matteo Cesana;Mauro Passacantando;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3003 - 3016
Editeur: IEEE
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» On Parallelizing Single Dynamic Simulation Using HPC Techniques and APIs of Commercial Software
Résumé:
Time-domain simulations are heavily used in today's planning and operation practices to assess power system transient stability, posttransient voltage/frequency profiles as well as oscillatory behavior following severe contingencies to comply with industry standards. Because of the increased modeling complexity, it is many times slower than real time for state-of-the-art commercial software packages to complete a dynamic simulation for a large-scale model. With the growing stochastic behavior introduced by emerging technologies, power industry has seen a growing need for performing security assessment in real time. This paper presents an innovative parallel implementation framework to speed up a single dynamic simulation by leveraging the existing stability model library in commercial tools through their application programming interfaces (APIs). Several high performance computing (HPC) techniques are explored and implemented such as parallelizing the calculation of generator current injection, identifying fast linear solvers for network solution, and parallelizing data outputs when interacting with APIs in the commercial package, TSAT. The proposed method has been tested on a Western Electricity Coordinating Council (WECC) planning base case with detailed synchronous generator models and it exhibits outstanding scalable performance with sufficient accuracy.
Auteurs: Ruisheng Diao;Shuangshuang Jin;Frederic Howell;Zhenyu Huang;Lei Wang;Di Wu;Yousu Chen;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2225 - 2233
Editeur: IEEE
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» On Secrecy Rate and Optimal Power Allocation of the Full-Duplex Amplify-and-Forward Relay Wire-Tap Channel
Résumé:
We present the secrecy rate of a relay wire-tap channel in which a source node communicates securely to a destination node in the presence of an eavesdropper using an amplify-and-forward (AF) relay operating in full-duplex (FD) mode. We explicitly account for the residual self-interference due to FD transmission and compute the optimal power allocation (PA) that maximizes the secrecy rate under both individual and joint power constraints of the source and the relay nodes. For slowly varying fading channels, we show that the optimal PA problem is quasiconcave and, hence, determine the globally optimal solution. Applying the method of dominant balance to analyze the capacity and PA schemes in different high-power regimes, we demonstrate that full PA at the relay is only necessary when the power at the relay is sufficiently small compared to the power at the source. Our results show that FD relaying achieves a significantly higher secrecy rate than half-duplex (HD) relaying. We extend the results to ergodic fading channels where the channel gains are assumed to be available at the receivers but not the transmitters. To this end, we first calculate the expectation of linear functions of exponentially distributed random variables using the exponential integral function. This method allows us to obtain a closed-form expression for the ergodic secrecy rate. The bisection method can then be applied to find the optimal PA scheme. Numerical results also reveal the superiority of FD over HD relaying in channels with ergodic fading.
Auteurs: Cuong Dang;Leonardo Jiménez-Rodríguez;Nghi H. Tran;Sachin Shetty;Shivakumar Sastry;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 3887 - 3899
Editeur: IEEE
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» On Stabilization of 2D Roesser Models
Résumé:
This note is devoted to the stabilization of 2D Roesser models which are discrete, continuous, or mixed continuous-discrete. A recent linear matrix inequalities (LMIs) necessary and sufficient condition for stability of such models is used to derive a quasi non conservative technique for state feedback stabilization.
Auteurs: Olivier Bachelier;Nima Yeganefar;Driss Mehdi;Wojciech Paszke;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2505 - 2511
Editeur: IEEE
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» On the Application of Inverse-Mode SiGe HBTs in RF Receivers for the Mitigation of Single-Event Transients
Résumé:
Best practice in mitigation strategies for single-event transients (SETs) in radio-frequency (RF) receiver modules is investigated using a variety of integrated receivers utilizing inverse-mode silicon–germanium (SiGe) heterojunction bipolar transistors (HBTs). The receivers were designed and implemented in a 130-nm SiGe BiCMOS technology platform. In general, RF switches, low-noise amplifiers (LNAs), and downconversion mixers utilizing inverse-mode SiGe HBTs exhibit less susceptibility to SETs than conventional RF designs, in terms of transient peaks and duration, at the cost of RF performance. Under normal RF operation, the SET-hardened switch is mainly effective in peak reduction, while the LNA and the mixer exhibit reductions in transient peaks as well as transient duration.
Auteurs: Ickhyun Song;Moon-Kyu Cho;Michael A. Oakley;Adrian Ildefonso;Inchan Ju;Stephen P. Buchner;Dale McMorrow;Pauline Paki;John. D. Cressler;
Apparue dans: IEEE Transactions on Nuclear Science
Date publication: 05.-2017, volume: 64, issue:5, pages: 1142 - 1150
Editeur: IEEE
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» On the Asymptotic Equivalence of Circulant and Toeplitz Matrices
Résumé:
Any sequence of uniformly bounded $Ntimes N$ Hermitian Toeplitz matrices ${H_{N}}$ is asymptotically equivalent to a certain sequence of $Ntimes N$ circulant matrices ${C_{N}}$ derived from the Toeplitz matrices in the sense that $left |{H_{N}- C_{N} }right |_{F} = o(sqrt {N})$ as $Nrightarrow infty $ . This implies that certain collective behaviors of the eigenvalues of each Toeplitz matrix are reflected in those of the corresponding circulant matrix and supports the utilization of the computationally efficient fast Fourier transform (instead of the Karhunen-Loève transform) in applications like coding and filtering. In this paper, we study the asymptotic performance of the individual eigenvalue estimates. We show that the asymptotic equivalence of the circulant and Toeplitz matrices implies the individual asymptotic convergence of the eigenvalues for certain types of Toeplitz matrices. We also show that these estimates asymptotically approximate the largest and smallest eigenvalues for more general classes of Toeplitz matrices.
Auteurs: Zhihui Zhu;Michael B. Wakin;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2975 - 2992
Editeur: IEEE
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» On the Broadcast Capacity Scaling of Large Wireless Networks at Low SNR
Résumé:
This paper focuses on the problem of broadcasting information in the most efficient manner in a large 2-D ad hoc wireless network at low SNR and under line-of-sight propagation. A new communication scheme is proposed, where source nodes first broadcast their data to the entire network, despite the lack of sufficient available power. The signal’s power is then reinforced via successive back-and-forth beamforming transmissions between different groups of nodes in the network, so that all nodes are able to decode the transmitted information at the end. This scheme is shown to achieve asymptotically the broadcast capacity of the network, which is expressed in terms of the largest singular value of the matrix of fading coefficients between the nodes in the network. A detailed mathematical analysis is then presented to evaluate the asymptotic behavior of this largest singular value.
Auteurs: Serj Haddad;Olivier Lévêque;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3242 - 3258
Editeur: IEEE
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» On the Chiroferrite Medium-Based Waveguide Dispersion Compensator
Résumé:
The letter investigates a kind of dispersion compensator composed of dual-core planar waveguide separated by isotropic dielectric medium. Both the resonantly coupled cores are comprised of anisotropic chiroferrite materials. A dielectric clad layer of silicon dioxide is combined adjacent to one of the core sections. Supermodes are generated through mode-coupling at the resonance frequency that lead to the investigation of the group velocity dispersion (GVD) feature of the structure. The chiroferrite material parameters, particularly the chiral admittance and gyrotropy of the cores, play vital roles in achieving high GVDs. A fine tuning of resonance is achieved through proper choice of the core material parameters, and the results would be useful to devise dispersion compensator for usage in communication systems.
Auteurs: N. Iqbal;P. K. Choudhury;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 715 - 718
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Design and Analysis of Reliable RRAM-CMOS Hybrid Circuits
Résumé:
Resistive switching memories (RRAMs) are one of the most promising alternatives for nonvolatile storage and nonconventional computing systems. However, their behavior, and therefore their reliability, is limited by technology intrinsic constraints. Standard CMOS reliability analyses do not take into account RRAM-related misbehaviors. Consequently, new and more thorough characterization approaches are needed. Even more important, as RRAM is proposed to become a key piece in aerospace solutions, new radiation and temperature analyses should also be considered in reliability-oriented methodologies. This work presents a solution that completely characterizes RRAM and CMOS hybrid circuits under the combined effects of both technology and environmental error sources. The analysis strategy is based on three pillars: the definition of suitable models, the application of user-defined metrics to measure both circuit reliability and performance, and the efficient definition of the design space. These concepts are used by a powerful simulation framework, achieving automatic characterization of RRAM-based circuits by simultaneously considering multiple error sources. As a case of study, a thorough analysis of an RRAM read driver, including RRAM lifetime, circuit temperature, CMOS and RRAM variability, and radiation—both accumulated dose and single particle impacts—highlights the proposed approach capabilities.
Auteurs: Fernando García-Redondo;Marisa López-Vallejo;
Apparue dans: IEEE Transactions on Nanotechnology
Date publication: 05.-2017, volume: 16, issue:3, pages: 514 - 522
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Effect of Disorder on Stray Capacitance of Transformer Winding in High-Voltage Power Supplies
Résumé:
Stray capacitance of transformer winding is an important parasitic element influencing the behavior of the switching power converters, especially for high-voltage transformers. There are various methods for calculating the stray capacitance in transformers and inductors with ordered windings. However, an ordered winding is less likely with an increased number of turns and layers. In this paper, it is shown that a slight disorderliness in winding leads to a considerable difference between the value of winding stray capacitance of the former ordered winding and its slightly disordered scheme. Therefore, regular methods for calculating the stray capacitance have significant errors in a disordered winding. A generic method is proposed to calculate the stray capacitance of a winding with disordered turns. The proposed method is to apply the probabilistic tools to evaluate the possible position of winding turns and calculation of stray capacitance for all possible winding diagrams. As the number of possible winding diagrams is very large, especially in high turn windings, Kolmogorov–Smirnov theorem is used to estimate the winding stray capacitance based on the reduced number of possible winding diagrams. The energy method is used to calculate the equivalent stray capacitance of winding. Using this calculation method, the effect of disorder and some other parameters on the value of stray capacitance is investigated. The proposed method is tested and validated with the computer simulation and the experimental measurement.
Auteurs: Morteza Aghaei;Shahriyar Kaboli;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3608 - 3618
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Electromagnetic Steel Selections and Performance Impact Assessments of Synchronous Reluctance Motors
Résumé:
To achieve relatively lower costs and higher operational efficiencies, without adopting permanent magnets or rotor conductors, the synchronous reluctance motor (SynRM) has received more and more attentions as a competitive solution recently. To establish a rational guidance for the related designs and constructions, this paper is aimed to present the thorough performance impact assessments of SynRMs that are composed of different electromagnetic steels at various operational specifications. Based on the magnetization and hysteresis characteristics of the steel sheets, variations of the average torques, torque ripples, and iron losses by using different stator and rotor materials are investigated, and some valuable comparison results can be provided for designers and engineers in the related motor and metal industries.
Auteurs: Cheng-Tsung Liu;He-Yu Chung;Sheng-Yang Lin;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2569 - 2577
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Feasibility of Breast Cancer Imaging Systems at Millimeter-Waves Frequencies
Résumé:
Medical imaging currently relies on several techniques, including X-rays, magnetic resonance, and echography. However, these techniques exhibit drawbacks, and alternative approaches are required. Microwave imaging has been proposed as a possible solution, especially for breast cancer imaging. However, most of these systems work with a central frequency of a few gigahertz, and this leads to a suboptimum resolution, which can jeopardize the image quality. Millimeter waves can provide superior resolutions, at the cost of a lower penetration depth within the breast tissue. In addition, a significant fraction of the power generated by a mm-wave imaging system would be reflected back from the skin. For these reasons, and also considering that mm-wave transmitters and receivers have been historically outperformed by microwave counterparts in terms of available power and sensitivity, mm-wave imaging has not been considered a possible solution. This paper contributes to demonstrate a paradigm shift toward the possible use of mm-waves for breast cancer imaging of targets a few centimeter below the skin, a useful penetration depth for several cases. All key points are addressed using analytical, full-wave, and multiphysics simulations, including the system architecture (linear and conformal), the safety aspects (power density, specific absorption rate, and temperature increase), and the use of realistic breast models derived from ex vivo measurements.
Auteurs: Simona Di Meo;Pedro Fidel Espín-López;Andrea Martellosio;Marco Pasian;Giulia Matrone;Maurizio Bozzi;Giovanni Magenes;Andrea Mazzanti;Luca Perregrini;Francesco Svelto;Paul Eugene Summers;Giuseppe Renne;Lorenzo Preda;Massimo Bellomi;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1795 - 1806
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Feasibility of Full-Duplex Relaying in Multiple-Antenna Cellular Networks
Résumé:
In this paper, we perform a system-level feasibility analysis of full-duplex (FD) relay-aided cellular networks that are equipped with multiple antennas at the base stations (BSs) and the relay nodes (RNs). The aim is to understand whether FD relaying is capable of enhancing the rate of cellular networks. With the aid of tools from stochastic geometry, we develop a tractable approach for computing the percentile rate, which allows us to gain insights on the impact of FD relaying for both the cell-edge and the cell-median mobile terminals subject to network interference. Contrary to previous works that do not consider the network interference, the framework reveals that even in the absence of self-interference at the FD RNs, a network with half-duplex (HD) RNs can outperform its FD counterpart for a moderate number of antennas at the BSs and RNs. On the other hand, the FD-based network can substantially outperform both the HD-based one and the one without RNs for a sufficiently large number of antennas at the BSs and RNs and substantially small self-interference power effect at the RNs. Finally, the aforementioned analytical insights are validated by means of Monte Carlo simulations.
Auteurs: Konstantinos Ntontin;Marco Di Renzo;Christos Verikoukis;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 2234 - 2249
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Fronthaul Statistical Multiplexing Gain
Résumé:
Breaking the fronthaul capacity limitations is vital to make cloud radio access network scalable and practical. One promising way is aggregating several remote radio units (RRUs) as a cluster to share a fronthaul link, so as to enjoy the statistical multiplexing gain brought by the spatial randomness of the traffic. In this letter, a tractable model is proposed to analyze the fronthaul statistical multiplexing gain. We first derive the user blocking probability caused by the limited fronthaul capacity, including its upper and lower bounds. We then obtain the limits of fronthaul statistical multiplexing gain when the cluster size approaches infinity. Analytical results reveal that the user blocking probability decreases exponentially with the average fronthaul capacity per RRU, and the exponent is proportional to the cluster size. Numerical results further show considerable fronthaul statistical multiplexing gain even at a small to medium cluster size.
Auteurs: Liumeng Wang;Sheng Zhou;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1099 - 1102
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On The Fundamental Energy Trade-offs of Geographical Load Balancing
Résumé:
Geographical load balancing can optimize the utilization of green energy and the cost of electricity by taking advantage of greenness and price diversities at geographically dispersed data centers. However, higher green energy utilization or lower electricity cost may actually increase the total energy consumption, and is not necessarily the best option. The achievable energy trade-offs can be captured by taking into consideration a defined service efficiency parameter for geo-dispersed data centers.
Auteurs: Abbas Kiani Kiani;Nirwan Ansari;
Apparue dans: IEEE Communications Magazine
Date publication: 05.-2017, volume: 55, issue:5, pages: 170 - 175
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Incident Power on a Receiving Slender Antenna and the Optical Theorem in the Near Field
Résumé:
Incident power upon a slender scatterer or a receiving antenna is not well defined, since physical apertures of such structures have little meaning. However, an area over which the incident power is admitted can nonetheless be defined. For a definition that relies solely on the receive mode, we develop a near-field version of the optical theorem. When equated with the conventional far-field version, an equation for the admitting area appears. This equation is solved via both a full-wave simulation and a quasi-analytical way. The result is also supported by two transmit-mode assessments. It is shown that under this definition, the half-wavelength dipole can be replaced by an equivalent aperture antenna facing the direction of the incident wave.
Auteurs: Hamid Shannan;Raphael Kastner;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2421 - 2427
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Limits of Coexisting Coverage and Capacity in Multi-RAT Heterogeneous Networks
Résumé:
This paper devises a general modeling and analyzing framework for a heterogeneous wireless network (HetNet) in which several wireless subnetworks coexist and use multiple radio access technologies (multi-RATs). The coexisting coverage and network capacity in such a multi-RAT HetNet are hardly investigated in prior works. To characterize the coexisting interactions in a multi-RAT HetNet, in this paper, we consider a HetNet consisting of $K$ tiers of access points (APs) and two different RATs, RAT- $ mathsf {L}$ and RAT- $ mathsf {U}$ , are adopted in the HetNet. RAT- $ mathsf {L}$ is adopted by the APs in the first $K-1$ tiers and APs in the $K$ th tier only use RAT- $ mathsf {U}$ . Both noncrossing-RAT and crossing-RAT user association scenarios are considered. In each scenario, the void probability and the channel access probability of the APs in each tier are first found and then the tight lower bounds and their lowest limits on the proposed coexisting coverage and network capacity are derived. We show that multi-RAT networks in general can achieve higher link coverage and capacity by using opportunistic carrier sense multiple access with collision avoidance that avoids/alleviates severe interfering between all coexisting APs. Also, crossing-RAT user association is shown to achieve much higher coexisting coverage and network capacity than noncrossing-RAT user association. Finally, numerical simulations for the LTE-U and WiFi networks coexisting in the HetNet valida- e our findings.
Auteurs: Chun-Hung Liu;Hong-Cheng Tsai;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3086 - 3101
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Optimal Set of Channels to Sense in Cognitive Radio Networks
Résumé:
In the channel selection problem, a secondary user (SU) senses a subset of size $M$ out of $N$ existing channels, and then accesses up to $K$ sensed-free channels. Given $M$ , $N$ , $K$ , and some estimates on the rates of channels, and the sensing accuracy, the channel selection problem asks what set of channels SU should sense to maximize its throughput. The intuitive answer is the set of $K$ channels with the highest rewards, where the reward of a channel is defined as the expected number of bits that can be successfully transmitted on that channel. Surprisingly, the above-mentioned intuitive solution is not optimal when $M>K$ . In this letter, we study the case $M>K$ , and propose polynomial-time optimal solutions for special cases where $K=1$ or where $M$ or $N-M$ are small. We also derive an upper bound on the maximum achievable throughput, and propose a generic near-optimal heuristic algorithm.
Auteurs: Afshin Arefi;Majid Khabbazian;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1103 - 1106
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Optimal Tone Spacing for Interference Mitigation in OFDM-IM Systems
Résumé:
Orthogonal frequency division multiplexing with index modulation (OFDM-IM) has been recently proposed as an efficient technique to improve the error performance and enhance the spectral efficiency achieved by the classical OFDM. In this letter, we minimize the presence of intercarrier and intersymbol interference, experienced by OFDM-IM systems under mobility conditions and multipath scenarios, by selecting the appropriate tone spacing between adjacent subcarriers. Finally, we prove that the optimal value of tone spacing increases the system capacity, occupying only the necessary amount of bandwidth, and provide closed-form expressions for the interference power per active subcarrier.
Auteurs: Georgia D. Ntouni;Vasileios M. Kapinas;George K. Karagiannidis;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1019 - 1022
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Optimization Model for Multi-Hop Information Transmission and Energy Transfer in TDMA-Based Wireless Sensor Networks
Résumé:
Wireless energy transfer (WET) has been considered a promising technique for prolonging the lifetime of wireless networks. In this letter, the joint optimization problem of multi-hop information transmission and energy transfer in TDMA-based multi-hop wireless sensor networks is modeled. Moreover, a more realistic energy consumption model is proposed, which takes the energy consumption of compression, communication, and wireless energy transfer into account. A nonlinear programming problem is formulated to achieve the maximal source rate utility. Finally, through the numerical results, the impact of system parameters on rate utility is investigated, and the role of WET in improving network performance is verified.
Auteurs: Weiqiang Xu;Weiwei Cheng;Yushu Zhang;Qingjiang Shi;Xiaodong Wang;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1095 - 1098
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Outage Probability of MIMO Full-Duplex Relaying: Impact of Antenna Correlation and Imperfect CSI
Résumé:
This paper analyzes the performance of multiple-input multiple-output (MIMO) full-duplex (FD) relaying systems, where the source and destination nodes are equipped with single antenna and communicate via a dual-hop amplify-and-forward (AF) relay with multiple receive and transmit antennas. The system performance due to practical wireless transmission impairments of spatial fading correlation and imperfect channel state information (CSI) is investigated. At the relay, the loopback self-interference (LI) is mitigated by using the receive zero-forcing (ZF) precoding scheme, then steering the signal to the destination by using a maximum and ratio transmission (MRT) technique. To this end, new exact closed-form expressions for the outage probability are derived, where the case of arbitrary, exponential, and no correlations are considered. Meanwhile, for better system performance insights, simpler outage probability lower bound expressions are also included, through which the achievable diversity order of the receive ZF/MRT scheme is shown to be $text{min}(N_{R}-1, N_{T})$ , where $N_{R}$ and $N_{T}$ are the number of relay receive and transmit antennas, respectively. Numerical results sustained by Monte Carlo simulations show the exactness and tightness of the proposed closed-form exact and lower bound expressions, respectively. In addition, it is seen that the outage probability performance of FD relaying outperforms that of the conventional half-duplex (HD) relaying at low to medium signal-to-noise ratio (SNR). However, at high SNR, the performance of HD relaying outperforms that of the FD relaying. Furthermore, in the presence of channel estimation errors, an outage probability error floor is seen at high SNR. Therefore, for optimum outage performance, hybr- d relaying modes that switches between HD and FD relaying modes is proposed.
Auteurs: Ahmed Almradi;Khairi Ashour Hamdi;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 3957 - 3965
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Performance of HARQ-IR Over Nakagami-m Fading Channels in Mobile Ad Hoc Networks
Résumé:
In this paper, outage performance of hybrid automatic repeat request (HARQ) with incremental redundancy over Nakagami-m fading channels in a mobile ad hoc network is analyzed. Different from prior analyses, both interlink interference and random distribution of the nodes are considered, which makes the analysis practical and challenging. Based on an orthogonal polynomial approximation, the probability distribution of the product of multiple shifted signal-to-interference-and-noise ratios (SINRs) and the outage probability are derived in closed forms. The impacts of various system parameters including the intensity of source nodes, the number of retransmissions and the packet rate on the outage probability are then studied thoroughly. The closed-form outage probability enables further analysis of a wide range of performance metrics and delay limited throughput (DLT) is particularly discussed here. It is found that a limited number of retransmissions is sufficient to achieve the maximum DLT. With the analytical results, the optimal packet rate to maximize the DLT is also found. To characterize the performance of the whole network, network DLT (NDLT), which is the maximum achievable aggregated DLT in a unit area under a certain outage constraint, is finally introduced. The scaling law of NDLT over the network density is revealed. Specifically, the NDLT scales linearly with the network density $lambda$ when the network is sparse, while it follows the $(1 - frac{alpha }{2})$ power law over the network density where $alpha$ is the path loss exponent when the network is dense.
Auteurs: Haichuan Ding;Zheng Shi;Shaodan Ma;Chengwen Xing;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 3913 - 3929
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Scaling Behavior of the Average Rate Performance of Large-Scale Distributed MIMO Systems
Résumé:
To support the massive data traffic in the near future, the distributed antenna system has become a promising candidate for the next-generation cellular system. Due to the lack of a closed-form expression, how the average rate performance scales with a large number of distributed base-station (BS) antennas is not well understood. This paper focuses on the average rate performance of the downlink channel of a large-scale distributed antenna system. By assuming that the number of BS antennas at each cluster $N_c$ and the number of user antennas $N_c$ go to infinity with $N/N_crightarrow eta$ , asymptotic lower-bounds of the average per-antenna capacities with and without channel state information at the transmitter side (CSIT) in the single-user case are characterized as an explicit function of the ratio $eta$ and the number of BS antenna clusters $L$. Simulation results verify that the average per-antenna capacities with and without CSIT logarithmically increase with $L$ in the orders of $Theta (frac{alpha }{2}log _2 L)$ and $Theta ((frac{alpha }{2}-1)log _2 L)$, respectively, where $alpha >text{2}$ is the path-loss factor. The analysis is further extended to the multiuser case with $K$ uniformly distributed users. By assuming that - inline-formula>$N,N_crightarrow infty$ with $N/N_crightarrow eta$ , an asymptotic lower-bound of the average per-antenna rate with block diagonalization (BD) is derived. Simulation results verify that the average per-antenna rate scales in the order of $Theta(log _2 frac{lfloor L-eta (K-1)rfloor ^{alpha /2}}{K})$ if the ratio $eta$ is fixed. The effect of the cluster size on the average rate performance is further analyzed. Simulation results verify that for a given number of BS antennas, the average per-antenna capacities with and without CSIT in the single-user case and the average per-antenna rate with BD in the multiuser case increase monotonically as the number of BS antennas at each cluster decreases, which indicates that a fully distributed BS antenna layout can achieve the highest average rate performance.
Auteurs: Zhiyang Liu;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4029 - 4043
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Secrecy Rate Maximization With Uncoordinated Cooperative Jamming by Single-Antenna Helpers
Résumé:
A practical uncoordinated cooperative jamming (UCJ) scheme is proposed in this paper to enhance the physical layer security of the single-input-single-output (SISO) wiretap channel. Differing from the existing works, all the helpers in this UCJ scheme are uncoordinated single-antenna uplink users, and each helper transmits a jamming signal independently to confound the eavesdropper. The intended receiver plays the role of base station in the cellular systems as well as a control center to properly allocate the jamming power of each helper to maximize the secrecy rate. Two cases are addressed in solving the secrecy rate maximization problem, namely, the global channel state information (CSI) case and the partial CSI case. The optimal solution is obtained in the global CSI case, and a near-optimal solution is obtained under the secrecy outage probability constraint in the partial CSI case. Numerical results show that the performance of the proposed scheme is comparable with the existing works.
Auteurs: Xiaoyan Hu;Pengcheng Mu;Bo Wang;Zongmian Li;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4457 - 4462
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Simulation of Everything
Résumé:
Affordable computing and memory capacity have enabled fascinating work in the "world" of computer visualization and simulation. As high-resolution complexities are modeled, offering new and sometimes unexpected results, these intricate artifacts answer questions while leading to new ones.
Auteurs: Vinton G. Cerf;
Apparue dans: IEEE Internet Computing
Date publication: 05.-2017, volume: 21, issue:3, pages: 103 - 104
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Spectral Efficiency of Selective Decode-and-Forward Relaying
Résumé:
Multirelay cooperative relaying enables spatial diversity, often at the expense of spectral efficiency. To alleviate the loss in spectral efficiency due to half-duplex relaying and transmission over orthogonal channels, we propose a novel transmission scheme for selective decode-and-forward (DF) networks. In this scheme, we assume that destination may receive signals from transmitting nodes with different modulation levels. Particularly, we obtain a closed-form expression for both end-to-end (E2E) average error probability and spectral efficiency in such a scheme. Subsequently, using these closed-form expressions and average channel statistics, we perform joint optimization of power allocation and modulation level selection to maximize the E2E spectral efficiency while maintaining a target E2E average error probability and a set of transmit power constraints. Simulation results demonstrate that the transmission scheme proposed herein improves the E2E spectral efficiency significantly, in comparison with the conventional adaptive DF transmission scheme.
Auteurs: Hamza Umit Sokun;Halim Yanikomeroglu;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4500 - 4506
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the Statistics of Coherence Estimators for Textured Clutter Plus Noise
Résumé:
This letter presents a theoretical analysis of the impact of thermal noise on the statistics of the classical as well as a modified estimator for the cross-correlation coefficient between two receive channels, which follow a noisy compound clutter model. This correlation coefficient, in the synthetic aperture radar (SAR) context often called coherence, is widely used as an important quality parameter in the field of SAR interferometry, SAR change detection, and SAR ground moving target indication. Based on a novel closed-form expressions for the probability density function (pdf) for integer number of averaged samples (or looks), it is shown that, contrary to widespread belief, the clutter texture does not cancel out when the noise contribution is taken into account. It is further demonstrated that the new pdfs can be used to derive the bias and variance of the sample coherence in analytical closed form. Thereby, the impact of the texture on the estimators is analyzed.
Auteurs: Christoph H. Gierull;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 679 - 683
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On the VLSI Energy Complexity of LDPC Decoder Circuits
Résumé:
Sequences of randomly generated bipartite configurations are analyzed; under mild conditions almost surely such configurations have minimum bisection width proportional to the number of vertices. This implies an almost sure $Omega (n^{2}/d^{2}_{mathrm {max}})$ scaling rule for the energy of directly-implemented low-density parity-check (LDPC) decoder circuits for codes of block length $n$ and maximum node degree $d_{mathrm {max}}$ . It also implies an $Omega (n^{3/2}/d_{mathrm {max}})$ lower bound for serialized LDPC decoders. It is also shown that all (as opposed to almost all) capacity-approaching, directly-implemented non-split-node LDPC decoding circuits, have energy, per iteration, that scales as $Omega left ({chi ^{2}ln ^{3} chi }right )$ , where $chi =(1-R/C)^{-1}$ is the reciprocal gap to capacity, $R$ is code rate, and $C$ is channel capacity.
Auteurs: Christopher G. Blake;Frank R. Kschischang;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2781 - 2795
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On Unified Numerical Algorithm for 3-D Scattering From Dielectric and PEC Random Rough Surfaces
Résumé:
We present a unified fast scattering algorithm for dielectric random rough surfaces that asymptotically reduces to the perfect electric conductor (PEC) case when the loss tangent grows extremely large. The Coifman wavelets are employed to implement Galerkin’s procedure in the method of moments (MoM). The Coiflets-based surface integral equations (IEs) consist of both the tangential and normal components of electromagnetic fields as unknowns. The inherited mathematical superiority, e.g., local multiresolution analysis and high regularity with Holder index 1.449 in smoothness, allows efficiently implementing both electric field IE and magnetic field IE. Due to the high-precision one-point quadrature, the Coiflets yield fast evaluations of the most off-diagonal entries, reducing the matrix fill effort from O(N2) to O(N). The orthogonality and Riesz basis of the Coiflets generate well-conditioned impedance matrix, with rapid convergence for the conjugate gradient solver. In addition, a semianalytical expression of the tapered-wave carried power is derived, which speeds up computations of the normalization factor of scattering coefficients. Numerical results demonstrate that the reduced PEC model does not suffer from ill-posed problems, namely, matrix condition numbers are kept small and solutions are stable under extremely large loss tangent, where normal components of $H$ -field and tangential $E$ -field have vanished. Compared with the previous publications and laboratory measurements, good agreement is observed.
Auteurs: Lisha Zhang;Guangwen George Pan;Jimmy A. Jones;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2615 - 2623
Editeur: IEEE
Document complet vers site de l'éditeur
 
» On-Chip Investigation of Phase Noise in Monolithically Integrated Gain-Switched Lasers
Résumé:
Phase noise in gain-switched lasers is investigated theoretically using the semiconductor laser rate equations and compared with the experimental results from monolithically integrated devices. The phase noise of a gain-switched laser is modelled both with and without injection-locking using the rate equations for a single-mode laser. Phase noise is found to increase with gain-switching, and decrease when injection-locked to a master laser. This trend is then observed experimentally on-chip with monolithically integrated devices without the use of an isolator.
Auteurs: Justin K. Alexander;Padraic E. Morrissey;Ludovic Caro;Mohamad Dernaika;Niall P. Kelly;Frank H. Peters;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 731 - 734
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Online Condition Monitoring for Both IGBT Module and DC-Link Capacitor of Power Converter Based on Short-Circuit Current Simultaneously
Résumé:
Insulated-gate bipolar transistor (IGBT) modules and dc-link capacitors are important parts in the majority of power electronic converters which contribute to cost, size, and failure rate on a considerable scale. This paper presents an online condition monitoring method for both IGBT modules and dc-link capacitors of power converters based on short-circuit current of an IGBT module, which is a good condition indicator according to the theory analysis. The failure prediction of dc-Link capacitor is realized by equivalent series resistance, which can be calculated by short-circuit current and a step voltage, and the bond wires fatigue can also be identified by the short-circuit current. The proposed method is capable for detecting small changes in the failure indicators of IGBT modules and electrolytic capacitors, and its effectiveness is validated by a confirmatory experiment. The novelty of the proposed method is that the degradations of IGBT modules and capacitors can be identified simultaneously, and has the merits of low cost and circuit simplicity
Auteurs: Pengju Sun;Can Gong;Xiong Du;Quanming Luo;Haibo Wang;Luowei Zhou;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3662 - 3671
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Online Optimal Operation of Parallel Voltage-Source Inverters Using Partial Information
Résumé:
In this paper, a novel optimal learning algorithm for partially unknown voltage-source inverters (VSIs) operating in parallel is presented. The algorithm designs game-theory-based distributed controllers to provide the appropriate working voltage magnitude and frequency at the load by converting dc voltage to ac voltage at the parallel VSIs. It takes advantage of information from the neighboring low pass $Lhbox{-}C$ filters to improve harmonic distortion and guarantee equal sharing of the load current across the VSIs while avoiding current circulation during transient and ensuring stability and robustness. It builds upon the ideas of approximate dynamic programming (ADP) and uses only partial information of the system and the exosystem, which is connected only to some of the VSIs. The proposed framework was tested in simulations to show its effectiveness.
Auteurs: Kyriakos G. Vamvoudakis;João P. Hespanha;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4296 - 4305
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Online Ski Rental for ON/OFF Scheduling of Energy Harvesting Base Stations
Résumé:
The co-existence of small cell base stations (SBSs) with conventional macrocell base station is a promising approach to boost the capacity and coverage of cellular networks. However, densifying the network with a viral deployment of SBSs can significantly increase energy consumption. To reduce the reliance on unsustainable energy sources, one can adopt self-powered SBSs that rely solely on energy harvesting. Due to the uncertainty of energy arrival and the finite capacity of energy storage systems, self-powered SBSs must smartly optimize their ON and OFF schedule. In this paper, the problem of ON/OFF scheduling of self-powered SBSs is studied, in the presence of energy harvesting uncertainty with the goal of minimizing the operational costs consisting of energy consumption and transmission delay of a network. For the original problem, we show that an algorithm can solve the problem in the illustrative case. Then, to reduce the complexity of the original problem, an approximation is proposed. To solve the approximated problem, a novel approach based on the ski rental framework, a powerful online optimization tool, is proposed. Using this approach, each SBS can effectively decide on its ON/OFF schedule autonomously, without any prior information on future energy arrivals. By using competitive analysis, a deterministic online algorithm and a randomized online algorithm (ROA) are developed. The ROA is then shown to achieve the optimal competitive ratio in the approximation problem. Simulation results show that, compared with a baseline approach, the ROA can yield performance gains reaching up to 15.6% in terms of reduced total energy consumption of SBSs and up to 20.6% in terms of per-SBS network delay reduction. The results also shed light on the fundamental aspects that impact the ON time of SBSs while demonstrating that the proposed ROA can reduce up to 69.9% the total cost compared with a bas- line approach.
Auteurs: Gilsoo Lee;Walid Saad;Mehdi Bennis;Abolfazl Mehbodniya;Fumiyuki Adachi;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2976 - 2990
Editeur: IEEE
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» Open-End Multilevel Six-Phase Machine Drive System With Five Three-Leg Converters
Résumé:
This paper proposes and investigates a multilevel ac six-phase motor drive. The system is composed of five isolated three-leg voltage source inverters feeding the open-end windings of an asymmetrical six-phase induction motor (SPIM), which is adequate to generate multilevel voltages for high-power systems with voltage rating restrictions. A simple space vector pulse-width modulation (PWM) based on three similar individual planes and its implementation by means of equivalent level-shifted PWM are presented. A space vector pattern with a high number of voltage vectors redundancies is obtained. These redundancies and the application sequence of the voltage vectors are selected to minimize the amount of changes in the switching states and to decrease the harmonic distortion of the generated voltages. The vector pattern of this optimal modulation is obtained by analyzing only one plane and applied in the same way to the three planes as if they were independent. The developed PWM techniques have low computational complexity and are suitable for low-cost hardware implementations. Simulation results are used to compare the proposed topology with a conventional configuration in terms of harmonic distortion and semiconductor losses. Experimental results demonstrate the feasibility of the proposed drive system.
Auteurs: Ayslan Caisson Norões Maia;Cursino Brandão Jacobina;Nayara Brandão de Freitas;Italo Roger Ferreira Moreno Pinheiro da Silva;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2271 - 2281
Editeur: IEEE
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» Open-End Nine-Phase Machine Conversion Systems
Résumé:
This paper proposes four open-end nine-phase conversion systems with a reduced number of controlled switches. For this to be achieved, a converter is shared among the three three-phase groups that compose the machine. In addition, in order to reduce the number of controlled switches even more, three of the studied topologies with a shared converter make use of diodes replacing some of the switches. Because of the shared converter, the configurations that make use of diodes are only applied for machines with no spatial shift between the machine three three-phase groups. Analysis of harmonic distortion for equal and unequal dc-link voltages is presented. It is shown that the harmonic distortion for configurations with diodes are higher when unequal dc-link voltages are used. Besides, study of machine torque ripple is performed and a pulse-width modulation strategy modification is made aiming torque ripple reduction for two of the proposed conversion systems. Simulation and experimental results are presented to validate the theoretical approach.
Auteurs: Victor Felipe Moura Bezerra Melo;Cursino Brandão Jacobina;Nayara Brandão de Freitas;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2329 - 2341
Editeur: IEEE
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» Open-Loop Coherent Distributed Arrays
Résumé:
The ability to cohere the wireless operations between separate, moving microwave systems enables significant increases in capability for remote sensing, radar, communications, and other microwave wireless applications. Open-loop coherent distributed arrays, which are distributed systems of nodes that coherently coordinate without external signal inputs from the destination, are introduced in this paper. A model of the signal received from a coherent distributed array is derived, and a statistical analysis of the variation in signal power in the presence of coordination errors is presented. Requirements on the tolerable errors for internode range measurement, beamsteering angle measurement, and internode clock phase synchronization are given as a function of the probability of achieving a given signal power. Approaches for achieving the necessary internode range and angle measurements are presented, and the experimental results of a novel one-way clock transfer approach to phase synchronization are shown. These examples demonstrate the feasibility of implementing coherent distributed arrays on moving platforms operating at frequencies extending into the microwave region.
Auteurs: Jeffrey A. Nanzer;Robert L. Schmid;Thomas M. Comberiate;Jason E. Hodkin;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1662 - 1672
Editeur: IEEE
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» Open-Loop Precoder Design for Spatial Multiplexing Systems in Transmit Correlated MIMO Channels
Résumé:
The performance of spatial multiplexing (SM) systems is significantly degraded in transmit correlated multiple-input multiple-output (MIMO) channels. In communication systems that are available for feedback, precoding can enhance performance by exploiting channel state information (CSI) at the transmitter. However, broadcasting systems have no reverse channel nor any CSI. Furthermore, channel mismatches in communication systems severely affect performance. For these systems, open-loop precoders that require no feedback CSI were proposed. However, an analytical precoder design method was not presented in the previous works. In this paper, we present an open-loop precoder design method for SM systems with a maximum-likelihood receiver in transmit correlated MIMO channels. We first describe how to design an open-loop precoder using a rotational matrix over the amplitude of the correlation. Our precoder design method is derived by observing the effect of correlation mismatch between the feedback CSI and the actual channel condition on a minimum Euclidean distance-based precoder. Next, we present a method to design an open-loop precoder that takes into account the impact of the phase of the correlation. For this precoder, a phase rotation matrix is added on the rotational matrix, and optimum parameters are obtained by maximizing the worst-case minimum distance for the phase of the correlation. The simulation results illustrate the validity of proposed open-loop precoder in transmit correlated MIMO channels.
Auteurs: Jungyup Jang;Dong Ho Kim;Ye Hoon Lee;Jong-Soo Seo;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 3843 - 3855
Editeur: IEEE
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» Open-Type Magnetic Shields for Optical Fiber Coil Protection With Coaxial Foil Tubes
Résumé:
To decrease the considerable nonreciprocal phase drift caused by environmental magnetic fields in fiber-optic gyroscope (FOG), magnetic shields on optical fiber coil (OFC) are necessarily used in medium- and high-accuracy FOG protection. Cubic boxes and spherical shells without any gaps have been widely adopted for decades in shields, posing challenge for tradeoff between weight limitation of shields and its shielding demand yet. Here, an open-type magnetic shields (OMSs) with several coaxial permalloy foil tubes in few hundred micrometers thickness is proposed, overlaying on the winding process of fiber coil and finally combining with OFC as an integration module (OFC-OMS). The shielding effectiveness (SE) and longitudinal availability were adjustable by changing permalloy tubes’ thickness, intervals between coaxial foil tubes, and extended length in endcaps. The optimized result showed that an OMS set with six coaxial permalloy foil tubes achieved a longitudinal availability of 82.6% for SE above 20dB in both axial and radial magnetic field and further revealed anisotropic shielding effect in axial magnetic field remarkably resulting in a 40-dB longitudinal availability of 70.1%. Total mass of OMS reduced by around 75% comparing with the conventional magnetic shields for OFC, which showed immense potentials on reduction of FOG size and processing cost.
Auteurs: Haixia Liu;Kaiming Liu;Zhenjiang Liang;Xiaojun Ma;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 7
Editeur: IEEE
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» OpenCL-Based FPGA-Platform for Stencil Computation and Its Optimization Methodology
Résumé:
Stencil computation is widely used in scientific computations and many accelerators based on multicore CPUs and GPUs have been proposed. Stencil computation has a small operational intensity so that a large external memory bandwidth is usually required for high performance. FPGAs have the potential to solve this problem by utilizing large internal memory efficiently. However, a very large design, testing and debugging time is required to implement an FPGA architecture successfully. To solve this problem, we propose an FPGA-platform using C-like programming language called open computing language (OpenCL). We also propose an optimization methodology to find the optimal architecture for a given application using the proposed FPFA-platform. According to the experimental results, we achieved 119 \sim 237 Gflop/s of processing power and higher processing speed compared to conventional GPU and multicore CPU implementations.
Auteurs: Hasitha Muthumala Waidyasooriya;Yasuhiro Takei;Shunsuke Tatsumi;Masanori Hariyama;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1390 - 1402
Editeur: IEEE
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» OpenFlow-Based Scalable Routing With Hybrid Addressing in Data Center Networks
Résumé:
In this letter, we propose an OpenFlow (OF)-based SCAlable Routing strategy (OSCAR) for modular data center networks (DCN) using a hybrid addressing mechanism. Each module in the DCN constitutes a segment in the network. Inter-segment routing is performed using virtual MAC (VMAC) ids assigned to the segments and intra-segment routing is done using IP addresses. OF provides central control over the network but it suffers from limited scalability in DCNs due to high control traffic. In OSCAR, the control traffic is minimized to achieve high scalability and flexibility in DCN routing.
Auteurs: Nabajyoti Medhi;Dilip Kumar Saikia;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1047 - 1050
Editeur: IEEE
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» Optical Characteristics of Silicon-Based Asymmetric Vertical Nanowire Photodetectors
Résumé:
Wavelength-selective absorption phenomena of silicon-based vertical nanowire (NW) photodetectors (PDs) are investigated using 3-D numerical simulations. The difference in the refractive indexes between silicon NW and its surrounding material induces diameter-dependent waveguide effects at several specificwavelengths for asymmetric as well as symmetric structures. But the asymmetric NW PDs with a large difference in diameter between the top side and the bottom side have loss of waveguide effects. All the NWPDs achieve high external quantum efficiency (EQE) peaks with an increase in NW height. Decreasing the NW pitch or increasing the NW density also increases the EQE peak values for awide range ofwavelengths, but too densely packed NWs induce high coupling between the nearest NWs, thus losing wavelength-selective properties. Vertical NW PDs having slightly bottom-wide asymmetric structure decrease reflectance and transmittance of the incident light because of the narrow top-side and wide bottom-side silicon NW cross sections, respectively, thus achieving higher EQEs. Bottom-wide asymmetric NW PDs are promising to enhance the optical characteristics as well as to maintain waveguide properties for optical sensor applications.
Auteurs: Jun-Sik Yoon;Kihyun Kim;M. Meyyappan;Chang-Ki Baek;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2261 - 2266
Editeur: IEEE
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» Optimal Caching and Scheduling for Cache-Enabled D2D Communications
Résumé:
To maximize offloading gain of cache-enabled device-to-device (D2D) communications, content placement and delivery should be jointly designed. In this letter, we jointly optimize caching and scheduling policies to maximize successful offloading probability, defined as the probability that a user can obtain desired file in local cache or via D2D link with data rate larger than a given threshold. We obtain the optimal scheduling factor for a random scheduling policy that can control interference in a distributed manner, and a low complexity solution to compute caching distribution. We show that the offloading gain can be remarkably improved by the joint optimization.
Auteurs: Binqiang Chen;Chenyang Yang;Zixiang Xiong;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1155 - 1158
Editeur: IEEE
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» Optimal Control for Congestion Pricing: Theory, Simulation, and Evaluation
Résumé:
This paper presents a mathematical framework for dynamic congestion pricing. The objective is to calculate an optimal toll using the optimal control theory. The problem consists of tolled lanes or routes and alternate non-tolled lanes or routes. The model is developed using a traffic conservation law, the queuing theory, and fundamental macroscopic relationships. A logit model is used for establishing the relationship between the price and the driver's choice behavior. We design a cost function and then use Hamilton–Jacobi–Bellman equation to derive an optimal control law that uses real-time information to determine an optimal tolling price. Simulations are performed to demonstrate the performance of this optimal control congestion-pricing algorithm.
Auteurs: Pushkin Kachroo;Saumya Gupta;Shaurya Agarwal;Kaan Ozbay;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1234 - 1240
Editeur: IEEE
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» Optimal Cooperative Content Caching and Delivery Policy for Heterogeneous Cellular Networks
Résumé:
To address the explosively growing demand for mobile data services in the 5th generation (5G) mobile communication system, it is important to develop efficient content caching and distribution techniques, aiming at significantly reducing redundant data transmissions and improving content delivery efficiency. In heterogeneous cellular network (HetNet), which has been deemed as a promising architectural technique for 5G, caching some popular content items at femto base-stations (FBSs) and even at user equipment (UE) can be exploited to alleviate the burden of backhaul and to reduce the costly transmissions from the macro base-stations to UEs. In this paper, we develop the optimal cooperative content caching and delivery policy, for which FBSs and UEs are all engaged in local content caching. We formulate the cooperative content caching problem as an integer-linear programming problem, and use hierarchical primal-dual decomposition method to decouple the problem into two level optimization problems, which are solved by using the subgradient method. Furthermore, we design the optimal content delivery policy, which is formulated as an unbalanced assignment problem and solved by using Hungarian algorithm. Numerical results have shown that the proposed cooperative content caching and delivery policy can significantly improve content delivery performance in comparison with existing caching strategies.
Auteurs: Wei Jiang;Gang Feng;Shuang Qin;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1382 - 1393
Editeur: IEEE
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» Optimal Data Scheduling and Admission Control for Backscatter Sensor Networks
Résumé:
This paper studies the data scheduling and admission control problem for a backscatter sensor network (BSN). In the network, instead of initiating their own transmissions, the sensors can send their data to the gateway just by switching their antenna impedance and reflecting the received RF signals. As such, we can reduce remarkably the complexity, the power consumption, and the implementation cost of sensor nodes. Different sensors may have different functions, and data collected from each sensor may also have a different status, e.g., urgent or normal, and thus we need to take these factors into account. Therefore, in this paper, we first introduce a system model together with a mechanism in order to address the data collection and scheduling problem in the BSN. We then propose an optimization solution using the Markov decision process framework and a reinforcement learning algorithm based on the linear function approximation method, with the aim of finding the optimal data collection policy for the gateway. Through simulation results, we not only show the efficiency of the proposed solution compared with other baseline policies, but also present the analysis for data admission control policy under different classes of sensors as well as different types of data.
Auteurs: Dinh Thai Hoang;Dusit Niyato;Ping Wang;Dong In Kim;Long Bao Le;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 2062 - 2077
Editeur: IEEE
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» Optimal Design for Offshore Wind Farm considering Inner Grid Layout and Offshore Substation Location
Résumé:
This paper introduces an efficient methodology to design optimally cable layout of inner grid as well as location of offshore substation. The methodology is composed of two optimizers: one is inner grid layout optimizer, which consists of several algorithms such as the k-clustering-based genetic algorithm, the minimum spanning tree, and the cable selection; the other one is offshore substation location optimizer based on the pattern search method. While performing iteratively two optimizers, alternatives for cable layout and candidates for location of offshore substation are generated and evaluated in the economic and reliability aspects, respectively. Optimal layout of offshore wind farm is determined so as to minimize the total cost which is a sum of construction, power loss, maintenance, and reliability costs.
Auteurs: Je-Seok Shin;Jin-O Kim;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2041 - 2048
Editeur: IEEE
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» Optimal Non-Uniform Deployments in Ultra-Dense Finite-Area Cellular Networks
Résumé:
Network densification and heterogenization through the deployment of small cellular access points (picocells and femtocells) are seen as key mechanisms in handling the exponential increase in cellular data traffic. Modeling such networks by leveraging tools from stochastic geometry has proven useful in understanding the fundamental limits imposed on network coverage and capacity by co-channel interference. Most of these works however assume infinite-sized and uniformly distributed networks on the Euclidean plane. In contrast, we study the finite-sized non-uniformly distributed networks, and find the optimal non-uniform distribution of access points, which maximizes network coverage for a given non-uniform distribution of mobile users and vice versa.
Auteurs: Pete Pratt;Carl P. Dettmann;Orestis Georgiou;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1139 - 1142
Editeur: IEEE
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» Optimal Reactive Power Dispatch With Accurately Modeled Discrete Control Devices: A Successive Linear Approximation Approach
Résumé:
In this paper, a novel solution to the optimal reactive power dispatch (ORPD) problem is proposed. The nonlinearity of the power flow equations is handled by a new successive linear approximation approach. For the voltage magnitude terms, a mathematical transformation that improves the accuracy and facilitates the linear modeling of shunt capacitors is used. Without loss of accuracy, the load tap changers and shunt capacitors are both modeled by linear constraints using discrete variables, which facilitates the linearly constrained mixed-integer formulation of the proposed ORPD model. An efficient iterative solving algorithm is introduced. The obtained solution strictly satisfies the power flow equations. Case studies on several IEEE benchmark systems show that the proposed algorithm can efficiently provide near-optimal solutions with the error of the objective functions of less than 0.1%. Compared with several commercial solvers, the proposed method shows distinct advantages in terms of both robustness and efficiency. Moreover, based on the round-off results, a heuristic method that reduces the optimization ranges of the discrete control variables is proposed. This method can further improve the computational efficiency with small losses in accuracy.
Auteurs: Zhifang Yang;Anjan Bose;Haiwang Zhong;Ning Zhang;Qing Xia;Chongqing Kang;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2435 - 2444
Editeur: IEEE
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» Optimal Relay Node Placement and Flow Allocation in Underwater Acoustic Sensor Networks
Résumé:
In recent years, underwater acoustic sensor networks (UASNs) have attracted widespread attention in academia. Prolonging the network lifetime is a crucial issue for UASNs. Compared with traditional wireless sensor networks (WSNs), stringent energy becomes more critical in UASNs because the battery equipped at sensor nodes has the limited amount of energy and it is much more difficult to replace or recharge in underwater circumstance. This fact motivates us to pursue the solutions to reduce power consumption by using relay nodes and flow allocation mechanism in order to extend the network lifetime. In this paper, the issues of relay node placement and the flow allocation have been considered as a joint problem and are formulated into an integer nonlinear programming problem, which is node placement-hard in general. To solve the problem efficiently, this paper proposes a novel heuristic scheme for UASNs, which works based on a 3-D architecture. The proposed scheme consists of three algorithms, named as Alternative Flow and Relay-node Adjustment as a whole. Extensive simulation experiments demonstrate that the proposed scheme offers a simple yet attractive solution to the problem.
Auteurs: Lingfeng Liu;Maode Ma;Chunfeng Liu;Yantai Shu;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 2141 - 2152
Editeur: IEEE
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» Optimal Selection of Phase Shifting Transformer Adjustment in Optimal Power Flow
Résumé:
Phase shifting transformers (PSTs) can be regulated to minimize total generation cost in optimal power flow problems. Under the perception that there exists multiple optimal solutions of PST angle adjustment and better economy may be achieved by controlling a small fraction of PSTs, this letter proposes a mixed integer linear programing model to optimally determine the subset of PSTs for angle adjustment. Numerical results on several test systems including large-scale systems show that the proposed model can provide better economic dispatch with regulating a small number of PSTs.
Auteurs: Tao Ding;Rui Bo;Zhaohong Bie;Xifan Wang;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2464 - 2465
Editeur: IEEE
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» Optimal Sleep-Wake Scheduling for Energy Harvesting Smart Mobile Devices
Résumé:
In this paper, we develop optimal sleep/wake scheduling algorithms for smart mobile devices that are powered by batteries and are capable of harvesting energy from the environment. Using a novel combination of the two-timescale Lyapunov optimization approach and weight perturbation, we first design the Optimal Sleep/wake scheduling Algorithm (OSA), which does not require any knowledge of the harvestable energy process. We prove that OSA is able to achieve any system performance that is within O(\epsilon) of the optimal, and explicitly compute the required battery size, which is O(1/\epsilon) . We then extend our results to incorporate system information into algorithm design. Specifically, we develop the Information-aided OSA algorithm (IOSA) by introducing a novel drift augmenting idea in Lyapunov optimization. We show that IOSA is able to achieve the O(\epsilon) close-to-optimal utility performance and ensures that the required traffic buffer and energy storage size are O(\log (1/\epsilon)^2) with high probability.
Auteurs: Longbo Huang;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1394 - 1407
Editeur: IEEE
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» Optimal Transport Over a Linear Dynamical System
Résumé:
We consider the problem of steering an initial probability density for the state vector of a linear system to a final one, in finite time, using minimum energy control. In the case where the dynamics correspond to an integrator ( $dot{x}(t) = u(t)$) this amounts to a Monge-Kantorovich Optimal Mass Transport (OMT) problem. In general, we show that the problem can again be reduced to solving an OMT problem and that it has a unique solution. In parallel, we study the optimal steering of the state-density of a linear stochastic system with white noise disturbance; this is known to correspond to a Schrödinger bridge. As the white noise intensity tends to zero, the flow of densities converges to that of the deterministic dynamics and can serve as a way to compute the solution of its deterministic counterpart. The solution can be expressed in closed-form for Gaussian initial and final state densities in both cases.
Auteurs: Yongxin Chen;Tryphon T. Georgiou;Michele Pavon;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2137 - 2152
Editeur: IEEE
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» Optimal WSN Deployment Models for Air Pollution Monitoring
Résumé:
Air pollution has become a major issue in the modern megalopolis because of industrial emissions and increasing urbanization along with traffic jams and the heating/cooling of buildings. Monitoring urban air quality is therefore required by municipalities and the civil society. Current monitoring systems rely on reference sensing stations that are precise but massive, costly, and, therefore, seldom. In this paper, we focus on an alternative or complementary approach, with a network of low cost and autonomic wireless sensors, aiming at a finer spatiotemporal granularity of sensing. Generic deployment models in the literature are not adapted to the stochastic nature of pollution sensing. Our main contribution is to design integer linear programming models that compute sensor deployments capturing both the coverage of pollution under time-varying weather conditions and the connectivity of the infrastructure. We evaluate our deployment models on a real data set of Greater London. We analyze the performance of the proposed models and show that our joint coverage and connectivity formulation is tight and compact, with a reasonable enough execution time. We also conduct extensive simulations to derive engineering insights for effective deployments of air pollution sensors in an urban environment.
Auteurs: Ahmed Boubrima;Walid Bechkit;Hervé Rivano;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2723 - 2735
Editeur: IEEE
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» Optimization and Analysis of Wireless Powered Multi-Antenna Cooperative Systems
Résumé:
In this paper, we consider a three-node cooperative wireless powered communication system consisting of a multi-antenna hybrid access point (H-AP) and a single-antenna relay and a single-antenna user. The energy constrained relay and user first harvest energy in the downlink and then the relay assists the user using the harvested power for information transmission in the uplink. The optimal energy beamforming vector and the time split between harvest and cooperation are investigated. To reduce the computational complexity, suboptimal designs are also studied, where closed-form expressions are derived for the energy beamforming vector and the time split. For comparison purposes, we also present a detailed performance analysis in terms of the achievable outage probability and the average throughput of an intuitive energy beamforming scheme, where the H-AP directs all the energy towards the user. The findings of the paper suggest that implementing multiple antennas at the H-AP can significantly improve the system performance, and the closed-form suboptimal energy beamforming vector and time split yields near optimal performance. Also, for the intuitive beamforming scheme, a diversity order of $frac {N+1}{2}$ can be achieved, where $N$ is the number of antennas at the H-AP.
Auteurs: Han Liang;Caijun Zhong;Himal A. Suraweera;Gan Zheng;Zhaoyang Zhang;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3267 - 3281
Editeur: IEEE
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» Optimization of Capacitive Membrane Sensors for Surface-Stress-Based Measurements
Résumé:
Surface stress-based measurement is a relatively new mechanism in biological and chemical sensing. The viability of this mechanism depends on the maximum sensitivity, accuracy, and precision that can be achieved with these sensors. In this paper, an analytical approximate solution and a finite-element model are employed to describe the electromechanical behavior of a surface stress-based sensor with capacitive measurements. In the proposed model, a circular membrane is assumed as the sensing component, while only a smaller concentric circular area of its surface is subjected to a change in surface stress. The presented approximate analytical solution has a good correspondence with the finite-element model and is computationally fast and accurate enough to be an effective design tool. Based on this modeling study, we can determine the optimum design of the sensor to obtain the maximum capacitive sensitivity. Moreover, we study the effect of this optimization on the precision of the system in surface stress sensing. This paper shows that the ratio of sensing area to the whole membrane plays a key role in the overall performance of such a sensor.
Auteurs: Banafsheh Sajadi;Hans Goosen;Fred van Keulen;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3012 - 3021
Editeur: IEEE
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» Optimization of LDPC Codes for PIN-Based OOK FSO Communication Systems
Résumé:
For middle/short-range terrestrial high-speed free-space optical (FSO) communication systems employing ON–OFF keying (OOK) and PIN photodiode receivers, the noise distribution is symbol-dependent, and the symmetry of the underlying communication channel cannot be assumed. Therefore, this letter employs the asymmetric density evolution technique and an optimization scheme combining four different search algorithms to optimize low-density parity-check (LDPC) codes for these FSO systems. Compared with the conventional LDPC codes that are designed assuming symbols-independent symmetric channels the optimized codes are much closer to the Shannon limit for OOK modulated binary non-symmetric channels.
Auteurs: Jun Ao;Jiwei Liang;Chunbo Ma;Guixing Cao;Cong Li;Yufei Shen;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 727 - 730
Editeur: IEEE
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» Optimization of Ni(Pt)/Si-cap/SiGe Silicidation for pMOS Source/Drain Contact
Résumé:
The Ni(Pt)/Si-cap/SiGe silicidation process has been optimized by modulating the Si-cap layer thickness and a cold Si preamorphization implantation (PAI), which effectively reduces the sheet resistance (Rs). In addition, it is revealed that PAI can obviously increase the Ni(Pt)Si grain size for a lower Rs.
Auteurs: Lin-Lin Wang;Jian-Chi Zhang;Yu-Long Jiang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2067 - 2071
Editeur: IEEE
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» Optimization of Scalable Broadcast for a Large Number of Antennas
Résumé:
In this paper, for a system incorporating a large number of antennas, we address the optimal space–time coding of multimedia scalable sources, which require unequal target error rates in their bitstream. First, in terms of the number of antennas, we analyze the behavior of the crossover point of the outage probability curves for the vertical Bell Laboratories space–time (V-BLAST) architecture with a linear or a maximum-likelihood receiver, and orthogonal space–time block codes (OSTBCs). We prove that, as the number of antennas increases with the transmission data rate fixed, the crossover point in outage probability monotonically decreases. This holds for any data rate employed by the system and is valid over propagation channels such as spatially correlated Rayleigh or Rician fading channels, as well as independent and identically distributed Rayleigh channels. We next show that, over such propagation channels with a large number of antennas, those analytical results can be used to simplify the computational complexity involved with the optimal space–time coding of a sequence of scalable packets, with no performance degradation.
Auteurs: Seok-Ho Chang;Jihwan P. Choi;Pamela C. Cosman;Laurence B. Milstein;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 3749 - 3764
Editeur: IEEE
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» Optimization of Signal to Noise Ratio in Silicon Nanowire ISFET Sensors
Résumé:
Inversion-mode (IM) and depletion-mode (DM) ion-sensitive field effect transistors (ISFETs) are investigated in terms of dc characteristics, pH response and low-frequency noise (LFN) characteristics. The dc characteristics show a low threshold voltage ( $text{V}_{mathrm{ TH}}$ ) of 28 mV for the DM ISFETs, which is preferred for the long lifetime of the pseudo-reference electrode. The DM ISFETs exhibit an enhanced pH response in the sub-threshold region, which comes from the lower sub-threshold swing. The LFN analysis for both devices shows similar level of noise equivalent current ( $text{I}_{mathrm{ n.RMS}}$ ) near $text{V}_{mathrm{ TH}}$ ; otherwise, a reduction of $text{I}_{mathrm{ n.RMS}}$ is obtained in the DM ISFETs in the linear region. In addition, the signal-to-noise ratio of the DM ISFETs is improved by 82.9% compared with the IM ISFETs in the sub-threshold region. Consequently, the DM ISFETs can be a better sensor platform for low-power, portable, and high-precision performance.
Auteurs: Hyeonsu Cho;Kihyun Kim;Jun-Sik Yoon;Taiuk Rim;M. Meyyappan;Chang-Ki Baek;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2792 - 2796
Editeur: IEEE
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» Optimization of the Close-to-Carrier Phase Noise in a CMOS–MEMS Oscillator Using a Phase Tunable Sustaining-Amplifier
Résumé:
In this paper, the phase noise of a 24-MHz complimentary metal–oxide–semiconductor microelectromechanical systems (CMOS-MEMS) oscillator with zero-level vacuum package is studied. We characterize and analyze the nonlinear regime of each one of the modules that compose the oscillator (CMOS sustaining-amplifier and MEMS resonator). As we show, the presented resonator exhibits a high nonlinear behavior. Such a fact is exploited as a mechanism to stabilize the oscillation amplitude, allowing us to maintain the sustaining-amplifier working in the linear regime. Consequently, the nonlinear resonator becomes the main close-to-carrier phase noise source. The sustaining amplifier, which functions as a phase shifter, was developed such that MEMS operation point optimization could be achieved without an increase in circuitry modules. Therefore, the system saves on area and power, and is able to improve the phase noise 26 dBc/Hz (at 1-kHz carrier frequency offset).
Auteurs: Guillermo Sobreviela;Martín Riverola;Francesc Torres;Arantxa Uranga;Núria Barniol;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 888 - 897
Editeur: IEEE
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» Optimized (2, 4) Stencil Runge–Kutta ADE-ADI FDTD With Application to Plasma
Résumé:
This paper discusses the improvement of the numerical dispersion characteristics of alternating direction implicit (ADI) finite-difference time-domain (FDTD) aimed at acquiring more accurate electromagnetic information of plasma. Through adding the optimization method, which is based on the optimization of spatial derivative to the (2, 4) stencil ADI FDTD, the optimized (2, 4) stencil ADI FDTD is proposed, and its unconditional stability is proved theoretically. The phase velocity error of the optimized (2, 4) stencil ADI FDTD versus propagation angle and grid density is investigated. In addition, the Runge–Kutta auxiliary differential equation (RKADE) scheme for tackling the constitutive relation equation of plasma is deduced, which is without additional storage occupation and computational burden compared with ADE scheme. Its numerical conductivity error is analyzed under different incident frequencies and electron collision frequencies. Through incorporating the RKADE scheme into the optimized (2, 4) stencil ADI FDTD, the optimized (2, 4) stencil RKADE-ADI FDTD is presented. The accuracy and relatively wideband capability of the proposed method is validated by two numerical experiments.
Auteurs: Song Wanjun;Zhang Hou;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2558 - 2565
Editeur: IEEE
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» Optimized Distributed Automatic Modulation Classification in Wireless Sensor Networks Using Information Theoretic Measures
Résumé:
Automatic modulation classification of digital signals is essential for intelligent communication systems. This paper addresses the distributed classification of digital amplitude-phase modulated signals in a system of multiple sensors, which observe the unknown signal corrupted with the additive white Gaussian noise. The sensors are connected to a fusion center through block-fading orthogonal multiple access channels. We introduce a new method, where: 1) for classification, an information-theoretic similarity measure known as correntropy is exploited by each local sensor; 2) for transmitting local decisions, an estimation of $a~priori$ probabilities is used by local sensors; and 3) for optimizing power allocation to each sensor, the Bhattacharyya distance is employed as the objective function by the fusion center. The proposed scheme improves the classification accuracy through exploiting channel diversity, which, in turn, enhances the overall performance. Simulation results validate the theoretically claimed improvement in the performance.
Auteurs: Saeed Hakimi;Ghosheh Abed Hodtani;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3079 - 3091
Editeur: IEEE
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» Optimized Nanocrystalline Silicon Oxide Impedance Immunosensor Electronic Tongue for Subfemtomolar Estimation of Multiple Food Toxins
Résumé:
Nanocrystalline silicon oxide (nc-SiO2) immunosensor array-based electronic tongue (E-tongue) has been recently reported to simultaneously detect multiple food toxins with subfemtomolar sensitivity. However, the quantification in these reports is quite imprecise leading to an error of more than 100%. In this paper, the quantification accuracy of multiple food toxin detection in the subfemtomolar range has been improved by more than 90% through upgraded design of the E-tongue system by incorporating two major modifications. First, the pore geometry of the nc-SiO2 immunosensors has been optimized to obtain the best combination of sensitivity, selectivity, and reproducibility through the evaluation of a figure of merit. Second, in the multivariate data processing using partial least squares discriminate analysis, additional input parameters corresponding to selectivity and standard deviations of the experimentally measured data have been incorporated. The final set of input parameters include peak frequency corresponding to maximum impedance sensitivity, bandwidth of the impedance sensitivity characteristics, cutoff frequency from noise spectroscopy, and their standard deviations. The optimized E-tongue system is capable of quantifying 0.1 fg/ml Aflatoxin B1 and Ochratoxin A with an error of only 10% and 20%, respectively, which is a remarkable achievement in the domain of food toxin detection. The proposed E-tongue system is low cost with minimal operator dependence and hence has immense potential for commercial deployment.
Auteurs: Hrilina Ghosh;Rahul Das;Chirasree RoyChaudhuri;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 964 - 973
Editeur: IEEE
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» Optimizing the Quality Factor of Quartz Tuning Fork Force Sensor for Atomic Force Microscopy: Impact of Additional Mass and Mass Rebalance
Résumé:
A force sensor in the heart of an atomic force microscope (AFM) plays a key role in the AFM measurements. Quartz tuning fork (QTF) based force sensor is attracting huge attention due to its peculiar traits such as self-actuating and sensing capability, high quality factor and high force sensitivity. Unfortunately, mounting a tip on a tine of the QTF degrades its quality (Q)-factor and sensitivity. Attaching an equivalent counter mass on the opposite tine (mass rebalance) can improve the Q-factor. We investigate the impact of the attached mass and counter mass on different traits of the QTF such as Q-factor, inherent relationship between excitation voltage and output as well as shift in the resonance frequency. We propose straight forward strategies to rebalance the QTF force sensor. Experimental results demonstrate that by attaching a counter mass (at the parallel position) on the opposite tine, the tip mass can be rebalanced. Q-factor is significantly improved after mass rebalance. The increase in the Q-factor depends on the mass of the tip, counter mass and position of the counter mass relative to the position of the tip ( ${r}_{p}$ ).
Auteurs: Danish Hussain;Jianmin Song;Hao Zhang;Xianghe Meng;Wen Yongbing;Hui Xie;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2797 - 2806
Editeur: IEEE
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» Optomechanical Transistor With Phonons and Photons
Résumé:
A better behaved and easily controlled optical communication device could improve the performance of signal transmission. Here, we present an optomechanical transistor within cavity-optomechanical system, where the coupled phonons–photons interfere with the input signal photons while the pump field controls the transmission spectrum of the signal laser. We demonstrate the existence of transmitted signal attenuation and amplification through the optomechanical transistor when switching OFF and ON the pump field, respectively. By increasing the input pump power, the output signal gain can be further enhanced abruptly. The proposed optomechanical transistor that has the advantages of simple manufacture technology, low cost, convenient replacement, normal working environment, and so on could be implemented in current experiments and pave the way for all-optical logic circuits and quantum repeaters.
Auteurs: Jinjin Li;Yanhui Chu;Jinyun Liu;Ka-Di Zhu;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3041 - 3044
Editeur: IEEE
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» Orientation-Independent Catheter-Based Characterization of Myocardial Activation
Résumé:
Cardiac electrogram (EGM) signals and electrophysiologic (EP) characteristics derived from them such as amplitude and timing are central to the diagnosis and therapeutic management of arrhythmias. Bipolar EGMs are often used but possess polarity and shape dependence on catheter orientation contributing to uncertainty. Objective: We describe a novel method to map cardiac activation that resolves signals into meaningful directions and is insensitive to electrode directional effects. Methods: Multielectrode catheters that span 2- and 3-D space are used to derive local electric field (E-field) signals. A traveling wave model of local EGM propagation motivates a new “omnipolar” reference frame in which to understand EGM E-field signals and provide bipolar component EGMs aligned with these anatomic and physiologic directions. We validate the basis of this technology and determine its accuracy using a saline tank in which we simulate physiologic propagation. Results: Omnipole signals from healthy tissue are nearly free of catheter orientation effects and are constrained by biophysics to consistent morphologies and thus consistent measured amplitudes and timings. Using a 3-D EP mapping system, traveling wave treatment, and omnipolar technology (OT) E-field loops, we derived a new and nearly instantaneous means to determine conduction velocity and activation direction. Conclusion: We describe the basis of OT and validate it with ablation and mapping catheters in a saline tank. Finally, we illustrate OT with signals from live subjects. Significance: OT's novel approach with signal processing and real-time visualization allows for a newly detailed characterization of myocardial activation that is insensitive to catheter orientation.
Auteurs: Don Curtis Deno;Ram Balachandran;Dennis Morgan;Faiz Ahmad;Stéphane Massé;Kumaraswamy Nanthakumar;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 1067 - 1077
Editeur: IEEE
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» Orthogonal or Superimposed Pilots? A Rate-Efficient Channel Estimation Strategy for Stationary MIMO Fading Channels
Résumé:
This paper considers channel estimation for multiple-input multiple-output (MIMO) channels and revisits two competing concepts of including training data into the transmit signal, namely, orthogonal pilot (OP) that periodically transmits alternating pilot-data symbols, and superimposed pilot (SP) that overlays pilot-data symbols over time. We investigate rates achievable by both schemes when the channel undergoes time-selective bandlimited fading and analyze their behaviors with respect to the MIMO dimension and fading speed. By incorporating the multiple-antenna factors, we demonstrate that the widely known trend in which the OP is superior to the SP in the regimes of high signal-to-noise ratio (SNR) and slow fading, and vice versa, does not hold in general. As the number of transmit antennas ( $ {n_{mathrm{ t}}}$ ) increases, the range of operable fading speeds for the OP is significantly narrowed due to limited time resources for channel estimation and insufficient fading samples, which results in the SP being competitive in wider speed and SNR ranges. For a sufficiently small $ {n_{mathrm{ t}}}$ , we demonstrate that as the fading variation becomes slower, the estimation quality for the SP can be superior to that for the OP. In this case, the SP outperforms the OP in the slow-fading regime due to full utilization of time for data transmission.
Auteurs: A. Taufiq Asyhari;Stephan ten Brink;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2776 - 2789
Editeur: IEEE
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» Orthogonal STBC for MDL Mitigation in Mode Division Multiplexing System With MMSE Channel Estimation
Résumé:
Mode division multiplexing (MDM) has the potential of increasing the capacity of optical fiber transmission system. However, primary impaired factor mode-dependent loss (MDL) poses fundamental performance limitations. Recently MIMO space time coding technique has provided a potential solution to mitigate the MDL and hence started receiving considerable interests. In this paper, orthogonal space time block coding (OSTBC)-based MDM transmission system was investigated to test its efficiency in mitigating MDL. Considering the importance and necessity of channel estimation for coherent receivers and the paucity of literature on this subject, MMSE channel estimation process was introduced in the MDM system to test the robustness and efficiency of the OSTBC-MDM system in mitigating the MDL. Furthermore, an alternative linear decoding (LD) method was achieved by transferring the orthogonal characteristics of codes in OSTBC to the channel elements in MDM system. The LD method has the same performance as the optimal ML method, excepting that it only exhibits linear computational complexity, in terms of the number of modes and the size of constellations. Simulation results were provided to validate the efficiency and robustness of the proposed OSTBC-MDM system in mitigating the MDL in the presence of MMSE channel estimation.
Auteurs: Yong Qiang Hei;Wen Tao Li;Xiao Chuan Xu;Ray T. Chen;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1858 - 1867
Editeur: IEEE
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» Outage Analysis of the Full-Duplex Decode-and-Forward Two-Way Relay System
Résumé:
Contrary to the traditional theoretical analysis with perfect self-interference cancellation, this paper studies the outage performance of a full-duplex (FD) decode-and-forward two-way relay system with the consideration of the residual self-interference incurred by the FD mode. The exact closed-form outage probability expressions are derived in this paper. In addition, the asymptotic outage performance is investigated when the transmit powers increase to infinity, and the result demonstrates that the outage probabilities monotonically increase and finally converge to 1 as the transmit power exceeds a certain threshold. Furthermore, optimal power allocation schemes and optimal relay node placement strategies are then proposed to improve the outage performance. Finally, simulation results are conducted to verify the accuracy of the theoretical analysis.
Auteurs: Cheng Li;Zhiyong Chen;Yafei Wang;Yao Yao;Bin Xia;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4073 - 4086
Editeur: IEEE
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» Outage Performance Analysis of Full-Duplex Relay-Assisted Device-to-Device Systems in Uplink Cellular Networks
Résumé:
This paper proposes a full-duplex cooperative device-to-device (D2D) communication system, where the relay employed can receive and transmit signals simultaneously. We adopt such a system to assist with D2D transmission. We first derive the conditional cumulative distribution function and the probability density function (pdf) of a series of channel parameters when the interference to the base station is taken into consideration and power control is applied at the D2D transmitter and the relay node. Then, we obtain an exact expression for the outage probability as an integral and as a closed-form expression for a special case, which can be used as a good approximation to the general case when residual self-interference is small. Additionally, we also investigate the power allocation problem between the source and the relay and formulate a suboptimal allocation problem, which we prove to be quasi-concave. Our analysis is verified by the Monte Carlo simulations, and a number of important features of full-duplex cooperative D2D communications can, thereby, be revealed.
Auteurs: Shuping Dang;Gaojie Chen;Justin P. Coon;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4506 - 4510
Editeur: IEEE
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» Outage Probability of Device to Device Communications Underlaying Cellular Network in Suzuki Fading Channel
Résumé:
Radio resource allocation in device-to-device (D2D) communications can be optimized by minimizing outage probability or maximizing throughput. In this letter, we derive two closed-form expressions for the outage probability of underlay D2D communications, by considering an additive white Gaussian noise, and large-scale and small-scale fading components. We jointly model small and large scale fading components by the Suzuki distribution and derive non-analytic integrals for the outage probability, which can be solved by Gauss–Laguerre quadrature and Gauss–Legendre quadrature numerical methods. We show that these formulas for the outage probability closely approach the simulation results. Our comparative study further shows that a low-complexity approximation belongs to the three-point Gauss–Legendre-based formula. Finally, random-based and Hungarian-based resource allocations are investigated.
Auteurs: Hossein Ghavami;Shahriar Shirvani Moghaddam;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1203 - 1206
Editeur: IEEE
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» Output-Tracking Quantized Explicit Nonlinear Model Predictive Control Using Multiclass Support Vector Machines
Résumé:
In applications involving digital control, the set of admissible control actions is finite/quantized. Coupled with state constraints and fast dynamics, explicit model predictive control (EMPC) provides an attractive control formalism. However, the design of data-driven EMPCs with finite admissible control sets is a challenging and relatively unexplored problem. In this paper, a systematic data-driven method is proposed for the design of quantized EMPCs (Q-EMPCs) for time-varying output tracking in nonlinear systems. The design involves: 1) sampling the admissible state space using low-discrepancy sequences to provide scalability to higher dimensional nonlinear systems; 2) at each sampled data point, solving for optimal quantized model predictive control actions and determining feasibility of the intrinsic mixed-integer nonlinear programming problem; and 3) constructing the Q-EMPC control surface using multiclass support vector machines (MC-SVMs). In particular, four widely used MC-SVM algorithms are employed to construct the proposed data-driven Q-EMPC. Extensive testing and comparison among the different MC-SVM algorithms is performed on 2-D and 5-D benchmark examples to demonstrate the effectiveness and scalability of the proposed methodology.
Auteurs: Ankush Chakrabarty;Gregery T. Buzzard;Stanisław H. Żak;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4130 - 4138
Editeur: IEEE
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» Over Second Octave Power Amplifier Design Based on Resistive–Resistive Series of Continuous Class-F/F−1 Modes
Résumé:
This letter presents a novel methodology for resistive–resistive series of continuous class-F/ $text{F}^{{mathbf {-1}}}$ modes (Res.–Res. SCF/ $text{F}^{{mathbf {-1}}}$ Ms) power amplifier (PA) design. The bandwidth is expanded by designing the lower band with resistive second- and third-harmonic impedances and the upper band with resistive second-harmonic impedance and reactive third-harmonic impedance using a waveform engineering method. Mathematical derivation of the methodology is described in detail. The proposed design is experimentally verified using a Res.–Res. SCF/ $text{F}^{{mathbf {-1}}}$ Ms PA operating across 0.4–2.3 GHz with 62.3%–80.5% drain efficiency and 39–42 dBm output power.
Auteurs: Qing-Hua Tang;Yang-Hua Li;Wen-Guang Li;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 494 - 496
Editeur: IEEE
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» Overcurrent Protection Response of a Hot Rolling Mill Filtering System: Analysis of the Process Conditions
Résumé:
This paper reproduces the abnormal operating conditions of a hot strip mill during different switching contingencies that may take place in the filtering system of the installation. Moreover, the evolution of the main electrical variables is predicted considering different characteristics of the steel to be milled. Within this work, the response of the overcurrent protection of the different filtering banks is analyzed along with different scenarios that could lead to switching operations in those filters. The analysis of the voltage stability and distortion at the point of common coupling (PCC), the evaluation of reactive power flows upstream of the PCC, the prediction of harmonic currents, and the study of the new operating conditions of the filters and the rolling stands under the said contingencies are assessed. The methodology described in this study provides the operator with important information on the expected electrical variables that can be extremely useful in deciding if the hot rolling mill can ride-through unexpected switching states of the filter banks. This forecast can avoid a good number of unscheduled stops, which could result in a significant reduction of production and economical losses.
Auteurs: Gonzalo Alonso Orcajo;Pablo Ardura G.;Josué Rodríguez D.;José M. Cano;Joaquín G. Norniella;Rocío Llera T.;Diego Cifrián R.;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2596 - 2607
Editeur: IEEE
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» Packet-Centric Tradeoff and Unfair Success Region in IEEE 802.11 WLANs
Résumé:
In this paper, we present a packet-centric analytical study of carrier sense multiple access with collision avoidance (CSMA/CA)-based medium access in wireless local area networks, specifically using the IEEE 802.11 distributed coordination function (DCF). The packet-centric viewpoint of analysis adds a new dimension of insights over those available in the existing body of knowledge in this domain. We propose an absorbing Markov chain-based model for analyzing the behavior of head-of-line frames of each station in such networks. We generalize the long-term and short-term unfairness induced by the randomness of the DCF protocol and depict the actual unfair success region to be avoided in fair resource allocation schemes. One of the primary objectives of any CSMA/CA-based medium access control (MAC) protocol is to increase the frame delivery probability, while reducing the average delay of delivery. With such considerations, we show a tradeoff relationship between the delivery probability and access delay with respect to the maximum retransmission limit in a packet-centric approach. We numerically evaluate the packet-centric behavior of the DCF protocol for single-hop single access point networks involving both the saturated and unsaturated stations, imperfect wireless channel, and varying payload sizes.
Auteurs: Sudip Misra;Manas Khatua;
Apparue dans: IEEE Transactions on Vehicular Technology
Date publication: 05.-2017, volume: 66, issue:5, pages: 4223 - 4230
Editeur: IEEE
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» Parameter Estimation of Resonant Fault Current Limiter for Protection and Stability Analysis
Résumé:
Aging or prolonged subjection to stressed conditions cause changes in the parameters of fault current limiter (FCL). These changes must be noticed to take remedial actions if necessary and to make sure whether the system fault current level is within the rated capacities of existing equipment or not. This paper presents a method for estimating parameters of a series resonant type FCL (RFCL) by using synchronized time-domain data from both ends of a transmission line. Estimated parameters during normal operation are used for protection and stability analysis of the system and fault data are used to analyze the performance of RFCL during fault. Electromagnetic transient line model is used to calculate the current and voltage across the device which are used to estimate the parameters of RFCL. PSCAD/EMTDC simulations are used to test the method. Applications of the parameter estimation method are also presented and as a demonstration, effect of variation in current limiting reactor on system transient stability is analyzed.
Auteurs: A. N. R. L. Sirisha;Ashok Kumar Pradhan;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2288 - 2295
Editeur: IEEE
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» Parametric Planning Model for Video Quality Evaluation of IPTV Services Combining Channel and Video Characteristics
Résumé:
Parametric planning models are designed for estimating the video quality, which can be applied to effective planning, implementation, and management of network video applications and communication networks. However, different from the bitstream-based evaluation models, the planning models are not allowed to exploit the video streams, with only limited information available for use, i.e., a few general parameters predetermined by the service providers and network operators. In this paper, a parametric planning model combining channel and video characteristics is proposed to estimate the video distortion caused by packet loss for Internet protocol television (IPTV) services. More specifically, the probability distribution of the channel states is determined by detailed analysis of the channel characteristics. Then, considering the influence of burst packet loss and the temporal dependence between frames, several sequence-level and frame-level parameters for video quality evaluation are derived from the perspective of the probability distribution of the channel states. Utilizing these parameters, the proposed model approximates the video quality considering the effects of direct packet loss and error propagation. Experimental results show that the proposed model has a superior performance for video quality estimation than the three commonly used parametric planning models.
Auteurs: Jiarun Song;Fuzheng Yang;Yicong Zhou;Shan Gao;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 05.-2017, volume: 19, issue:5, pages: 1015 - 1029
Editeur: IEEE
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» Partial Discreteness: A Novel Prior for Magnetic Resonance Image Reconstruction
Résumé:
An important factor influencing the quality of magnetic resonance (MR) images is the reconstruction method that is employed, and specifically, the type of prior knowledge that is exploited during reconstruction. In this work, we introduce a new type of prior knowledge, partial discreteness (PD), where a small number of regions in the image are assumed to be homogeneous and can be well represented by a constant magnitude. In particular, we mathematically formalize the partial discreteness property based on a Gaussian Mixture Model (GMM) and derive a partial discreteness image representation that characterizes the salient features of partially discrete images: a constant intensity in homogeneous areas and texture in heterogeneous areas. The partial discreteness representation is then used to construct a novel prior dedicated to the reconstruction of partially discrete MR images. The strength of the proposed prior is demonstrated on various simulated and real k-space data-based experiments with partially discrete images. Results demonstrate that the PD algorithm performs competitively with state-of-the-art reconstruction methods, being flexible and easy to implement.
Auteurs: Gabriel Ramos-Llordén;Arnold J. den Dekker;Jan Sijbers;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 05.-2017, volume: 36, issue:5, pages: 1041 - 1053
Editeur: IEEE
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» Partial Hard Thresholding
Résumé:
We study iterative algorithms for compressed sensing that have an “orthogonalization” step at each iteration to keep the residual orthogonal to the span of those columns of the measurement matrix that have been selected so far. To unify the design and analysis of such algorithms, we propose a novel partial hard-thresholding (PHT) operator that is similar to the hard thresholding operator but restricts the amount by which the support set can change in one iteration. Using the PHT operator and its properties, we provide a general framework to prove support recovery results for iterative algorithms employing this operator as well as those employing the hard-thresholding operator. Next, based on the PHT operator, we propose a novel family of algorithms. At one end of our family of algorithms lie well-known hard thresholding algorithms iterative thresholding with inversion and hard thresholding pursuit, whereas at the other end, we get a novel algorithm that we call orthogonal matching pursuit with replacement (OMPR). Like the classic greedy algorithm OMP, OMPR too adds exactly one coordinate to the support of the iterate at each iteration based on the correlation with the current residual. However, unlike OMP, OMPR also removes one coordinate from the support. This simple change allows us to prove that OMPR has the best known guarantees for sparse recovery in terms of the restricted isometry property (RIP), a condition on the measurement matrix. In contrast, OMP is known to have very weak performance guarantees under RIP. Finally, we show that most of the existing “orthogonalized” iterative algorithms, such as CoSaMP, subspace pursuit, OMP, can be expressed using the PHT operator. As a pleasing consequence of our novel and generic results for the PHT operator, we provide the tightest known RIP analysis of all of the above-mentioned iterative algorithms: CoSaMP, subspace pursuit, and OMP.
Auteurs: Prateek Jain;Ambuj Tewari;Inderjit S. Dhillon;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3029 - 3038
Editeur: IEEE
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» Partitioned Stator Machines With NdFeB and Ferrite Magnets
Résumé:
Partitioned stator (PS) machines employ two separated stators to accommodate armature windings and permanent magnets (PMs), respectively, alleviating the space conflict in stator-PM machines, and hence boosting the torque density. However, the PM usage volume in PS machines is relatively large, and thus the material cost is high, which is undesirable for the cost-sensitive applications. In this paper, a PS machine employing ferrite PM is presented, which takes advantage of larger available space for PMs while balances the performance and cost. The electromagnetic characteristics of an optimized ferrite PS machine and an NdFeB PS machine are evaluated together with a classic Prius2010 interior PM (IPM) machine as a baseline. Meanwhile, the economic issues are considered. The results reveal that the NdFeB PS machine has higher torque density than the Prius2010 IPM machine, but is more expensive, while the ferrite PS machine can significantly reduce the cost and still exhibit good performance. The demagnetization behavior of the ferrite PS machine is evaluated and a new method to improve the demagnetization withstand capability is proposed. Moreover, the mechanical analysis is conducted for the cupped rotor of PS machines. Finally, a pair of small-scaled prototypes are manufactured to validate the predictions.
Auteurs: Hao Hua;Z. Q. Zhu;C. Wang;Mei Zheng;Zhongze Wu;Di Wu;Xiao Ge;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 1870 - 1882
Editeur: IEEE
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» Passive Tuning of Optical Couplers Using a Thin-Film Cladding Material
Résumé:
This letter reports the demonstration of a novel method to passively tune the splitting ratio of a Ti-indiffused lithium niobate (LiNbO3) 3-dB directional coupler by the addition of a silicon-rich nitride cladding material. Plasma-enhanced chemical vapor deposition of such cladding layer onto a coupler alters the effective index of the odd and even modes in the coupled waveguide. By varying the thickness of the thin-film cladding layer, we are able to precisely control the coupling ratio and compensate for variations arising from fabrication tolerances that can significantly impact coupling.
Auteurs: Ugochukwu J. Nsofor;Peng L. Yao;Shouyuan Shi;Dennis W. Prather;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 775 - 778
Editeur: IEEE
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» Past as Prolog(ue): Humans, Machines, and 20 Years of Internet Computing
Résumé:
To celebrate IEEE Internet Computing's 20th anniversary, William Regli reflects on writing the lead technical article of the inaugural issue in 1997. Some of the observations he made two decades ago, as this discipline arose, were temporal in nature, and indicative of the times. Others, however, carried a certain prescience while distilling enduring themes.
Auteurs: William Regli;
Apparue dans: IEEE Internet Computing
Date publication: 05.-2017, volume: 21, issue:3, pages: 8 - 10
Editeur: IEEE
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» Path Setup for Hybrid NoC Architectures Exploiting Flooding and Standby
Résumé:
Future many-core systems will require energy-efficient, high-throughput and low-latency communication architectures. Silicon Photonics appears today a promising solution towards these goals. The inability of photonics networks to perform inflight buffering and logic computation suggests the use of hybrid photonic-electronic architectures. In order to exploit the full potential of photonics, it is essential to carefully design the path-setup architecture, which is a primary source of performance degradation and power consumption. In this paper, we propose a new path-setup approach which can put allocated circuits in a stand-by state, rapidly restoring them when needed. Path-setup messages are sent using a flooding routing strategy to enhance the possibility of finding free optical paths. We compare the proposed approach with a commonly used path-setup strategy as well as some other alternatives available. The results exhibit encouraging improvements in terms of both performance and energy consumption.
Auteurs: Edoardo Fusella;José Flich;Alessandro Cilardo;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1403 - 1416
Editeur: IEEE
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» Patient-Specific Finite-Element Simulation of the Insertion of Guidewire During an EVAR Procedure: Guidewire Position Prediction Validation on 28 Cases
Résumé:
Objective: Validation of a numerical method to compute arterial deformations under the insertion of an “extra-siff” guidewire during Endovascular Repair of Abdominal Aortic Aneurysm. Methods: We propose the validation of a previously developed simulation method. The model is calibrated using anatomical hypothesis and intraoperative observations. Simulation results are blindly evaluated against 3-D imaging data acquired during the surgical procedure on 28 patients, based on the predicted position of the intraoperative guidewire. Results: Simulation was successfully conducted on the 28 patients. The mean position error given by the Modified Hausdorff Distance for the 28 cases was 3.8 ± 1.9 mm, which demonstrates very good results for most of the cases. Conclusion: The work reported here shows that numerical simulation can predict some rather large variations in the vascular geometry due to tools insertion, for a wide variety of aorto-iliac morphologies. This is a new step toward clinically applicable mechanical simulation. Significance: Validation on 3-D intraoperative data on a large number of cases—robustness on adverse anatomies.
Auteurs: J. Gindre;A. Bel-Brunon;M. Rochette;A. Lucas;A. Kaladji;P. Haigron;A. Combescure;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 1057 - 1066
Editeur: IEEE
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» Pattern Reconfigurable Antenna Based on Morphing Bistable Composite Laminates
Résumé:
In this paper, a novel pattern reconfigurable antenna based on morphing bistable composite laminates is presented. The bistable asymmetric glass-fiber reinforced polymer (GFRP) composite laminates have two stable configurations with curvatures of opposite signs. The antenna pattern is reconfigured by transforming the configuration of the bistable GFRP laminate which acts as the substrate of the antenna. The coplanar waveguide transmission lines feeding technique is used for the microstrip quasi-Yagi antenna. A prototype of the proposed antenna is fabricated using a semi-automatic screen printer and an autoclave. The transformation between the two stable states of the proposed antenna using Ni/Ti shape memory alloy springs is investigated experimentally. The out-of-plane displacements, reflection coefficients and radiation patterns for the two stable configurations of the antenna are measured, which agree well with the simulated results. The main beam direction is 89° and 59° for the two stable configurations, respectively. In addition, the influences of various bending radii on the radiation patterns are investigated to gain a thorough understanding of the reconfigurable mechanism of the proposed antenna. Finally, a two-element array of such an antenna is presented and measured. The proposed antenna provides a potential application in multifunctional, conformal, morphing, and integrated structures.
Auteurs: Jianqiang Hu;Shu Lin;Fuhong Dai;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2196 - 2207
Editeur: IEEE
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» PBL-SEE: An Authentic Assessment Model for PBL-Based Software Engineering Education
Résumé:
The problem-based learning (PBL) approach has been successfully applied to teaching software engineering thanks to its principles of group work, learning by solving real problems, and learning environments that match the market realities. However, the lack of well-defined methodologies and processes for implementing the PBL approach represents a major challenge. The approach requires great flexibility and dynamism from all involved, whether in mapping content, in teacher performance, or laying out the process of how learners should go about solving problems. This paper suggests that management processes can help in implementing PBL throughout its life cycle (planning, implementation, monitoring, and enhancement), and proposes an assessment model called PBL-SEE for use in software engineering education (SEE). Two examples of its use are provided. The results show how the model can be applied and how the resulting information can be used to make the PBL initiatives “authentic,” in that they bring the reality of the labor market to the learning environment, while keeping to PBL principles.
Auteurs: Simone C. dos Santos;
Apparue dans: IEEE Transactions on Education
Date publication: 05.-2017, volume: 60, issue:2, pages: 120 - 126
Editeur: IEEE
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» PBTI Investigation of MoS2 n-MOSFET With Al2O3 Gate Dielectric
Résumé:
For the first time, we report the positive bias temperature instability of the back gated multilayer MoS2 n-MOSFETs with Al2O3 gate dielectric. In the stress phase, the ${I}_{d}$ ${V}_{g}$ curve shifts to the positive gate bias. In the recovery phase, it shifts back to the negative gate bias. After 5000 s recovery, it completely recovers to that of the fresh device. The results indicate that the voltage shift is solely due to trapping and detrapping of the pre-existing border traps in the Al2O3 dielectric. The traps consist of fast and slow components with the capture time constants of 7 and $ {1.8}times {10}^{2}$ s and the emission time constants of 15 and ${1.0}times {10}^{3}$ s, respectively. The results from first-order trapping and detrapping calculations are in overall agreements with 12 measured $Delta {V}_{g}$ curves including six under stress voltages and six in the recovery phases. The energy densities for the fast and slow traps are derived to be in the order of 1013 cm $^{-2}$ eV $^{-1}$ above the bottom of the MoS2 conduction band.
Auteurs: Hui-Wen Yuan;Hui Shen;Jun-Jie Li;Jinhai Shao;Daming Huang;Yi-Fang Chen;P. F. Wang;S. J. Ding;Albert Chin;Ming-Fu Li;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 677 - 680
Editeur: IEEE
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» Perceptual Spatial Audio Recording, Simulation, and Rendering: An overview of spatial-audio techniques based on psychoacoustics
Résumé:
Developments in immersive audio technologies have been evolving in two directions: physically motivated systems and perceptually motivated systems. Physically motivated techniques aim to reproduce a physically accurate approximation of desired sound fields by employing a very high equipment load and sophisticated, computationally intensive algorithms. Perceptually motivated techniques, however, aim to render only the perceptually relevant aspects of the sound scene by means of modest computational and equipment load. This article presents an overview of perceptually motivated techniques, with a focus on multichannel audio recording and reproduction, audio source and reflection culling, and artificial reverberators.
Auteurs: Huseyin Hacihabiboglu;Enzo De Sena;Zoran Cvetkovic;James Johnston;Julius O. Smith III;
Apparue dans: IEEE Signal Processing Magazine
Date publication: 05.-2017, volume: 34, issue:3, pages: 36 - 54
Editeur: IEEE
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» Performance Analysis and Optimization for SWIPT Wireless Sensor Networks
Résumé:
This paper investigates and optimizes the performance of simultaneous wireless information and power transfer (SWIPT) in wireless sensor networks over Nakagami- $m$ fading channels. In the considered system, there is one mobile reader ( $R$ ), which is equipped with one transmit antenna and one receive antenna, and a group of passive sensors. The information delivery includes two stages: 1) $R$ broadcasts a command with radio-frequency energy to the sensors, which adopt time splitting (TS)/power splitting (PS) schemes to harvest energy and 2) sensors deliver their information to $R$ over orthogonal channels by using the harvested energy. In this paper, we propose a unified framework to study and optimize the impact of SWIPT on the system performance with both TS and PS schemes. First, we characterize the probability density function and cumulative distribution function of the signal-to-interference-plus-noise-ratio in high signal-to-noise ratio region, then we study the outage and ergodic capacity performance of the backward links. The approximated closed-form expressions for the outage probability and ergodic capacity are derived and validated through Monte Carlo simulations. Finally, we also evaluate the energy efficiency of the target system, and propose an optimal splitting scheme for TS and PS to maximize the throughput of the target system.
Auteurs: Gaofeng Pan;Hongjiang Lei;Yi Yuan;Zhiguo Ding;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 2291 - 2302
Editeur: IEEE
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» Performance Analysis of Receive Space Modulation in the Shadowing MIMO Broadcast Channel
Résumé:
In this paper, the performance analysis of Receive Space Modulation (RSM) in the shadowing Multiple-Input Multiple-Output (MIMO) broadcast channel is presented. This is undertaken by considering Zero Forcing (ZF) precoding and both small and large scale fading. In particular, a closed form and accurate framework for the evaluation of the Symbol Error Rate (SER) is derived. In addition, the diversity order and the coding gain of the new architecture are also obtained. The derived framework can be directly extended to the conventional spatially multiplexed shadowing MIMO broadcast channel. It is shown that RSM achieves the same diversity order and, in certain scenarios which are well defined, higher coding gain than spatially multiplexing (SMX). Also, the performance difference between RSM and SMX in the shadowing broadcast channel is mathematically quantified. Finally, numerical results that verify the new framework and conclusions are provided.
Auteurs: Athanasios Stavridis;Marco Di Renzo;Peter M. Grant;Harald Haas;
Apparue dans: IEEE Transactions on Communications
Date publication: 05.-2017, volume: 65, issue:5, pages: 1972 - 1983
Editeur: IEEE
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» Performance Analysis of TanDEM-X Quad-Polarization Products in Pursuit Monostatic Mode
Résumé:
Since 2010, the two twin synthetic aperture radar (SAR) satellites TerraSAR-X and TanDEM-X have been acquiring high-resolution images to generate a global Earth's digital elevation model (DEM). Both satellites have been flying in a controlled close orbit formation, acquiring data in the nominal bistatic stripmap single-polarization mode. Once the acquisition of the dataset for the generation of the DEM has been completed, the flexibility offered by both SAR instruments in terms of interferometric, imaging, and polarization modes has been further exploited to demonstrate the different capabilities of the TanDEM-X experimental modes. By activating the dual-receive antenna mode, full polarimetric data can be acquired. For the first time, it has been possible to systematically command quad-polarization acquisitions in a dedicated TanDEM-X mission science phase, started in October 2014. In this paper, we present a first performance analysis and quality assessment of such quad-polarization products. The SAR image resolution and the noise equivalent sigma zero have been evaluated to show the quality of the focused SAR products. The influence of different instrument parameters on the SAR and interferometric performance, such as chirp bandwidth, pulse repetition frequency, or block adaptive quantization, has been investigated as well. For the evaluation of the interferometric performance, key parameters such as coherence and interferometric phase error have been analyzed. In this paper, the obtained results are presented and recommendations are given for the optimization in the commanding of TanDEM-X quad-polarization acquisitions.
Auteurs: José-Luis Bueso-Bello;Michele Martone;Pau Prats-Iraola;Carolina González-Chamorro;Thomas Kraus;Jens Reimann;Marc Jäger;Benjamin Bräutigam;Paola Rizzoli;Manfred Zink;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1853 - 1869
Editeur: IEEE
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» Performance and Stability Benchmarking of Monolithic 3-D Logic Circuits and SRAM Cells With Monolayer and Few-Layer Transition Metal Dichalcogenide MOSFETs
Résumé:
For the first time, considering the architecture of monolithic 3-D integration, we evaluate and benchmark the performance of 3-D logic circuits and stability/performance of 3-D 6T SRAM cells with monolayer and few-layer transition metal dichalcogenide (TMD) devices based on ITRS 2028 (5.9 nm) technology node. The impact of random variations on the cell stability is also investigated. With the possibility of adopting monolayer or few-layer TMDs for nFET- and pFET-tiers enabled by monolithic 3-D integration, this paper indicates that the trilayer TMD device may substantially degrade the performance of 3-D logic circuits in spite of its higher mobility. This paper also reveals that stacking the monolayer pFET-tier over the bilayer nFET-tier may provide better nominal stability and read/write performance for 6T superthreshold SRAM compared with the planar technology, whereas the optimum 3-D configuration for near-/sub-threshold operations appears to be the monolayer pFET-tier over the monolayer nFET-tier. Besides the 6T cell structure, 8T SRAM cells are also investigated with monolithic 3-D integration for near-threshold/subthreshold operation. The monolayer nFET-tier over the bilayer pFET-tier configuration is shown to be the optimum 3-D 8T near-threshold/subthreshold cell design.
Auteurs: Chang-Hung Yu;Pin Su;Ching-Te Chuang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2445 - 2451
Editeur: IEEE
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» Performance Enhancement of MEMS-Based INS/UWB Integration for Indoor Navigation Applications
Résumé:
Inertial navigation system (INS) has an increasingly important role in indoor navigation, which mainly uses inertial measurement units based on a micro electro mechanical system (MEMS) to acquire data, and which is independent of the external environment. However, INS has serious accumulated errors, and thus, it was often integrated with wireless location systems (WLSs), such as ultra wideband (UWB) system, in order to enhance the position performance. Namely, MEMS-based inertial sensors have the problem of random errors. Besides, a UWB system is vulnerable to external environment conditions, such as the non-line-of-sight (NLOS) factor and multipath effects, and thus, many outliers are produced. In order to improve the overall performance of the INS/UWB system, this paper proposes the three-tier approach based on: 1) analysis and pre-filtering of random errors of MEMS-based inertial sensors, and use of a complementary filter to provide attitude information of navigation system; 2) use of the anti-magnetic ring (AMR) to eliminate the outliers from the UWB system in NLOS environment; and 3) improvement of positioning accuracy at information fusion level using the double-state adaptive Kalman filter. The proposed approach was verified by experiments that included AMR test and filter test. The obtained results have validated the proposed method efficiency.
Auteurs: Qigao Fan;Biwen Sun;Yan Sun;Xiangpeng Zhuang;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3116 - 3130
Editeur: IEEE
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» Performance Evaluation of Bilayer Graphene Nanoribbon Tunnel FETs for Digital and Analog Applications
Résumé:
The recent advancement in the fabrication of narrow graphene nanoribbon with smooth edges has catalyzed the growth of nanoribbon based transistors. Motivated by these advances, we suggest bilayer graphene nanoribbon tunnel field-effect transistors (BLGNR-TFETs) for low voltage digital and analog applications. The device performance is analyzed by quantum transport simulation, based on self-consistent solutions of two-dimensional Poisson's equation and nonequilibrium Green's function formalism. The results indicate that the use of BLGNR-TFET instead of monolayer graphene nanoribbon TFET with very narrow width, increases the ON current and reduces the intrinsic device delay without lowering the ON/OFF current ratio. The BLGNR-TFET for analog/RF applications has provided higher intrinsic gain at very narrow ribbon width; however, very narrow width reduces the cutoff frequency. Furthermore, RF figure of merits are investigated in the presence of external parasitics.
Auteurs: Brajesh Rawat;Roy Paily;
Apparue dans: IEEE Transactions on Nanotechnology
Date publication: 05.-2017, volume: 16, issue:3, pages: 411 - 416
Editeur: IEEE
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» Performance Evaluation of Self Backhauled Small Cell Heterogeneous Networks
Résumé:
We compare the performance of heterogeneous networks (HetNets) with self backhauled small cells (SBSCs) relative to those with wired backhaul based small cells (WBSCs). The comparisons are made for a variety of SBSC based HetNets including: 1) when the HetNets employ omni antennas at the SBSCs and Uniform PF at the macro; 2) with directional antennas at the SBSCs and uniform PF at the macro; 3) with directional antennas at the SBSCs and weighted PF at the macro; and 4) with Directional antennas at the SBSCs and QoS-aware PF at the macro. The study catalogs our learning experiences with SBSC HetNets, leading the reader through the sequence of enhancements made to improve the performance of SBSC HetNets relative to WBSC HetNets.
Auteurs: Matthew Andrews;Arunabha Ghosh;Rahul N. Pupala;Subramanian Vasudevan;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3102 - 3110
Editeur: IEEE
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» Performance Evaluation of the Triangle-Based Empirical Soil Moisture Relationship Models Based on Landsat-5 TM Data and In Situ Measurements
Résumé:
Surface soil moisture (SSM) is an important parameter at the land-atmosphere interface. In past decades, passive microwave remote sensing offers a good opportunity for obtaining SSM on a global scale, and many downscaling methods have been proposed using the triangle-based empirical soil moisture relationship models to overcome the limitation of coarse spatial resolution of its SSM products for regional applications. This paper aimed to examine and compare the effectiveness of five typical triangle-based empirical soil moisture relationship models for estimating SSM with Landsat-5 data and in situ measurements from the Maqu network on the northeastern part of the Tibetan Plateau for nine cloud-free days. The results showed that the model that treats the SSM as a second-order polynomial with land surface temperature, vegetation indices (VIs), and surface albedo as inputs exhibited the best performance compared with the results of other models. The VI comparison indicated that the use of the normalized difference VI or the fractional vegetation cover in this model outperformed other VIs, with the root-mean-square deviation of approximately 0.055 m3/m3 and the coefficient of determination ($text{R}^{2}$ ) above 0.78 at the nine-day average level. In addition, a significant spatial scale effect of the model was also found through analyzing the model fitting results at different window sizes. The study provides important insight into the best empirical relationship models for capturing soil moisture dynamics. These models can support the passive microwave soil moisture data spatial downscaling and validation applications in future studies.
Auteurs: Wei Zhao;Ainong Li;Huaan Jin;Zhengjian Zhang;Jinhu Bian;Gaofei Yin;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2632 - 2645
Editeur: IEEE
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» Performance Improvement and Current Collapse Suppression of Al2O3/AlGaN/GaN HEMTs Achieved by Fluorinated Graphene Passivation
Résumé:
In this letter, fluorinated graphene (FG) is utilized to passivate GaN surface for a metal–insulator–semiconductor high electron mobility transistor (MIS HEMT). The FG-MIS HEMT achieves better DC characteristics than a traditional MIS HEMT, including larger saturation drain current density (34.3%), higher peak trans-conductance (14.4%), lower ON-resistance (21.6%), and lower off-state leakage. Moreover, current collapse measurement reveals that not only can FG suppress the drain saturation current reduction of MIS HEMT from 41.8% to 8.1% at off-state drain bias of 50 V, but also it prevents dynamic ON-resistance increasing with off-state stress. The coverage of FG on GaN surface can prevent GaN being oxidized and N diffusion from GaN during gate dielectric deposition, thus suppressing the formation of Ga-O bonds and Ga dangling bonds, leading to an excellent interface condition for Al2O3/GaN with reduced fixed interface charges. Therefore, significant passivation effect is achieved.
Auteurs: Lingyan Shen;Dongliang Zhang;Xinhong Cheng;Li Zheng;Dawei Xu;Qian Wang;Jingjie Li;Duo Cao;Yuehui Yu;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 596 - 599
Editeur: IEEE
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» Performance Investigation of a Nonlinear Energy Harvester With Random Vibrations and Subthreshold Deterministic Signals
Résumé:
In the field of energy harvesting, it has been demonstrated that under the appropriate conditions, nonlinear configurations of the harvester can provide better performance, compared with linear resonant oscillators; the performance is quantified in terms of the amount of energy extracted from environmental mechanical or seismic vibrations. In this paper, the results of investigations on a system for energy harvesting from wideband vibrations, using a nonlinear snap-through-buckling configuration and two piezoelectric actuators, placed at the stable minima of the potential energy function that underpins the dynamics of the flexible beam are presented. A nonlinear model is proposed that can describe the device behavior when it is driven by a suprathreshold deterministic signal, a wideband noise, or a subthreshold signal superimposed onto a (usually bandlimited) noise background. In the latter case, the system is seen to exhibit the so-called “stochastic resonance” behavior. The bandwidth of the nonlinear energy harvester is about 15 Hz, which is compatible with vibrational energy sources at low frequencies, e.g., a walking human. The device is seen to generate power up to 160~\mu text{W} when subject to a noise limited at 15 Hz. The power is sufficient to operate a standard wireless sensor node and the conversion efficiency of the harvester is about 12%.
Auteurs: Bruno Andò;Salvatore Baglio;Vincenzo Marletta;Antonio Pistorio;Adi R. Bulsara;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 992 - 1001
Editeur: IEEE
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» Performance Limit Projection of Germanane Field-Effect Transistors
Résumé:
Here we explore the performance limit of monolayer germanane (GeH) field-effect transistors (FETs). We first plotted an electronic band structure of GeH using density functional theory and then tight-binding parameters were extracted. Device characteristics of GeH FETs are investigated using rigorous self-consistent atomistic quantum transport simulations within tight-binding approximations. Our simulation results indicate that GeH FETs can exhibit exceptional on-state device characteristics, such as high $text{I}_{textit {on}}$ (>2 mA/ $mu text{m}$ ) and large $text{g}_{m}$ (~7 mS/ $mu text{m}$ ) with $text{V}_{textit {DD}} = 0.5$ V due to the very light effective mass of GeH (0.07m0), while maintaining excellent switching characteristics (SS ~64 mV/dec). We have also performed a scaling study by varying the channel length, and it turned out that GeH FET can be scaled down to ~14-nm channel without facing significant short channel effects but it may suffer from large leakage current at the channel length shorter than 10 nm. Finally, we have benchmarked GeH FET against MoS2 counterpart, exhibiting better suitability of GeH device for high-performance applications compared with MoS2 transistors.
Auteurs: AbdulAziz AlMutairi;Yiju Zhao;Demin Yin;Youngki Yoon;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 673 - 676
Editeur: IEEE
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» Performance of a Nano-CNC Machined 220-GHz Traveling Wave Tube Amplifier
Résumé:
We report on hot test measurements of a wide-bandwidth, 220-GHz sheet beam traveling wave tube amplifier developed under the Defense advanced research projects agency (DARPA) HiFIVE program. Nano-computer numerical control (CNC) milling techniques were employed for the precision fabrication of double vane, half-period staggered interaction structures achieving submicrometer tolerances and nanoscale surface roughness. A multilayer diffusion bonding technique was implemented to complete the structure demonstrating wide bandwidth (>50 GHz) with an insertion loss of about −5 dB achieved during transmission measurements of the circuit. The sheet beam electron gun utilized nanocomposite scandate tungsten cathodes that provided over 438-A/cm2 current density in the 12.5:1 ratio sheet beam. An InP HBT-based monolithic microwave integrated circuit preamplifier was employed for TWT gain measurements in the stable amplifier operation region. In the wide-bandwidth operation mode (for gun voltage of 20.9 kV), a gain of over 24 dB was measured over the frequency range of 207–221 GHz. In the high-gain operation mode (for gun voltage of 21.8 kV), over 30 dB of gain was measured over the frequency range of 197–202 GHz. High-power tests were conducted employing an extended interaction klystron.
Auteurs: Anisullah Baig;Diana Gamzina;Takuji Kimura;John Atkinson;Calvin Domier;Branko Popovic;Logan Himes;Robert Barchfeld;Mark Field;Neville C. Luhmann;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2390 - 2397
Editeur: IEEE
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» Performance of Minimum Mean-Square Error Beam Forming for Polarimetric Phased Array Weather Radar
Résumé:
In this paper, the development of a polarimetric phased array weather radar, which consists of a dual-polarized antenna with 2-D circular planar phase-array elements, is discussed. The radar is capable of measuring the 3-D rainfall distribution in less than several tens of seconds. Digital beamforming (DBF) is an important component in the development process of the phased array radar. In this paper, precipitation radar signal simulations are performed taking into consideration radar concepts in order to discuss the estimation accuracy of polarimetric precipitation profiles (differential reflectivity, specific differential phase, and copolar correlation coefficient) with two DBF methods that are based on Fourier and minimum mean-square error (MMSE) methods. A comparison of the performance of the two methods indicates that MMSE is superior in accuracy because of the effect of a stable and a robust main lobe and adaptively suppressed side lobes. MMSE also provides precipitation measurements eliminating the directional dependence of a beam pattern for improving the accuracy of measurements. It is also shown that the estimated accuracies of the precipitation profiles are almost independent of the number of pulses.
Auteurs: Hiroshi Kikuchi;Ting Wu;Eiichi Yoshikawa;Tomoo Ushio;Hideto Goto;Fumihiko Mizutani;Masakazu Wada;V. Chandrasekar;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2757 - 2770
Editeur: IEEE
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» Performance of Silicone Rubber Insulators Under Thermal and Electrical Stress
Résumé:
In recent times, high temperature vulcanized (HTV) silicone rubber insulators (SIR) are being widely used for overhead high voltage transmission and distribution systems. However, over a period, the insulator surface will be exposed to high temperature in several places, particularly in desert areas; further accumulation of pollutants can alter the temperature distribution along the insulator. In the present work, long-term electrothermal experimentation is carried out on various types of full-scale insulator units. The effect of temperature on pollution performance of SIR insulators is studied, and a novel and simple methodology to achieve uniform contamination layer on inherently hydrophobic HTV SIR insulator samples is presented. A specially fabricated oven having a provision for high voltage connection and facility for measurement of leakage currents is provided. Furthermore, study of migration of low molecular weight, recovery trends of hydrophobicity, and changes in material properties using scanning electron microscopy Fourier transform infrared spectroscopy is carried out.
Auteurs: Rahul Chakraborty;Subba Reddy B;
Apparue dans: IEEE Transactions on Industry Applications
Date publication: 05.-2017, volume: 53, issue:3, pages: 2446 - 2454
Editeur: IEEE
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» Permanent and Transient Fault Tolerance for Reconfigurable Nano-Crossbar Arrays
Résumé:
This paper studies fault tolerance in switching reconfigurable nano-crossbar arrays. Both permanent and transient faults are taken into account by independently assigning stuck-open and stuck-closed fault probabilities into crosspoints. In the presence of permanent faults, a fast and accurate heuristic algorithm is proposed that uses the techniques of index sorting, backtracking, and row matching. The algorithm’s effectiveness is demonstrated on standard benchmark circuits in terms of runtime, success rate, and accuracy. In the presence of transient faults, tolerance analysis is performed by formally and recursively determining tolerable fault positions. In this way, we are able to specify fault tolerance performances of nano-crossbars without relying on randomly generated faults that is relatively costly regarding that the number of fault distributions in a crossbar grows exponentially with the crossbar size.
Auteurs: Onur Tunali;Mustafa Altun;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 747 - 760
Editeur: IEEE
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» PERMIT: Network Slicing for Personalized 5G Mobile Telecommunications
Résumé:
5G mobile systems are expected to meet different strict requirements beyond the traditional operator use cases. Effectively, to accommodate needs of new industry segments such as healthcare and manufacturing, 5G systems need to accommodate elasticity, flexibility, dynamicity, scalability, manageability, agility, and customization along with different levels of service delivery parameters according to the service requirements. This is currently possible only by running the networks on top of the same infrastructure, the technology called network function virtualization, through this sharing of the development and infrastructure costs between the different networks. In this article, we discuss the need for the deep customization of mobile networks at different granularity levels: per network, per application, per group of users, per individual users, and even per data of users. The article also assesses the potential of network slicing to provide the appropriate customization and highlights the technology challenges. Finally, a high-level architectural solution is proposed, addressing a massive multi-slice environment.
Auteurs: Tarik Taleb;Badr Mada;Marius-Iulian Corici;Akihiro Nakao;Hannu Flinck;
Apparue dans: IEEE Communications Magazine
Date publication: 05.-2017, volume: 55, issue:5, pages: 88 - 93
Editeur: IEEE
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» Personalized Assessment as a Means to Mitigate Plagiarism
Résumé:
Although every educational institution has a code of academic honesty, they still encounter incidents of plagiarism. These are difficult and time-consuming to detect and deal with. This paper explores the use of personalized assessments with the goal of reducing incidents of plagiarism, proposing a personalized assessment software framework through which each student receives a unique problem set. The framework not only auto-generates the problem set but also auto-marks the solutions when submitted. The experience of using this framework is discussed, from the perspective of both students and staff, particularly with respect to its ability to mitigate plagiarism. A comparison of personalized and traditional assignments in the same class confirms that the former had far fewer observed plagiarism incidents. Although personalized assessment may not be cost-effective in all courses (such as language courses), it still can be effective in areas such as mathematics, engineering, science, and computing. This paper concludes that personalized assessment is a promising approach to counter plagiarism.
Auteurs: Sathiamoorthy Manoharan;
Apparue dans: IEEE Transactions on Education
Date publication: 05.-2017, volume: 60, issue:2, pages: 112 - 119
Editeur: IEEE
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» Peter Hilton on Naming
Résumé:
Host Felienne Hermans talks with Peter Hilton about why naming is much harder than we think, why it matters in programming and program comprehension, and how to improve your naming skills.
Auteurs: Felienne Hermans;
Apparue dans: IEEE Software
Date publication: 05.-2017, volume: 34, issue:3, pages: 117 - 120
Editeur: IEEE
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