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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 05-2017 trié par par titre, page: 7
» 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-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 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 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 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 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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» 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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» 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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» 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 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 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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» 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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» 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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» Phase Noise Estimation and Suppression for PDM CO-OFDM/OQAM Systems
Résumé:
Phase noise induced common phase error and inter-carrier-interference are serious impairments for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) systems. As have been discussed in previous publications, extra signal-to-noise-ratio (SNR) penalty is required to maintain the system performance under the interference of laser phase noise. The SNR penalty is proportional to the laser linewidth, the time duration of an OFDM symbol, and the system SNR. Therefore, the phase noise induced interference remains the bottleneck for CO-OFDM systems, especially for those systems employing high-order modulation formats, or with long fast Fourier transform window. Thanks to the usage of specially designed filter banks, CO-OFDM/offset quadrature amplitude modulation (CO-OFDM/OQAM) systems demonstrate lower out-of-band leakage and higher spectral efficiency compared with conventional CO-OFDM systems. Recently, both theoretical studies and experimental demonstrations for CO-OFDM/OQAM systems have been widely reported. With the relaxation of orthogonal condition from the complex field to the real field, phase noised induced interference in CO-OFDM/OQAM systems is more complicated than that in conventional CO-OFDM systems. To our best knowledge, there have been no studies on the phase noise estimation and suppression methods for CO-OFDM/OQAM systems. In this paper, we systematically study and analyze phase noise induced interference for CO-OFDM/OQAM systems. Based on the theoretical analysis and the concept of orthogonal basis expansion, we develop a time-domain phase noise estimation and suppression method for polarization-division-multiplexed CO-OFDM/OQAM systems. As shown in numerical Montel Carlo simulations, the proposed method can improve the system robustness against phase noise effectively.
Auteurs: Xi Fang;Fan Zhang;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1837 - 1846
Editeur: IEEE
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» Phase Retrieval for Wavelet Transforms
Résumé:
This paper describes a new algorithm that solves a particular phase retrieval problem, with important applications in audio processing: the reconstruction of a function from its scalogram, that is, from the modulus of its wavelet transform. It is a multiscale iterative algorithm that reconstructs the signal from low-to-high frequencies. It relies on a new reformulation of the phase retrieval problem that involves the holomorphic extension of the wavelet transform. This reformulation allows to propagate phase information from low-to-high frequencies. Numerical results, on audio and non-audio signals, show that reconstruction is precise and stable to noise. The complexity of the algorithm is linear in the size of the signal, up to logarithmic factors. It can thus be applied to large signals.
Auteurs: Irène Waldspurger;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2993 - 3009
Editeur: IEEE
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» Phenomenological Transparency
Résumé:
Translucent objects such as fog, clouds, smoke, glass, ice, and liquids are pervasive in cinematic environments because they frame scenes in depth and create visually-compelling shots. Unfortunately, they are hard to render in real-time and have thus previously been rendered poorly compared to opaque surfaces. This paper introduces the first model for a real-time rasterization algorithm that can simultaneously approximate the following transparency phenomena: wavelength-varying (“colored”) transmission, translucent colored shadows, caustics, volumetric light and shadowing, partial coverage, diffusion, and refraction. All render efficiently with order-independent draw calls and low bandwidth. We include source code.
Auteurs: Morgan McGuire;Michael Mara;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1465 - 1478
Editeur: IEEE
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» Photonic Generation of Linear-Frequency-Modulated Waveforms With Improved Time-Bandwidth Product Based on Polarization Modulation
Résumé:
Polarization modulation of two phase-correlated, orthogonally polarized wavelengths by a parabolic waveform is a promising way to generate linear-frequency-modulated (LFM) signals, but the time-bandwidth product (TBWP) of the generated LFM signal is intrinsically limited by the achievable modulation index of the polarization modulator (PolM). In this paper, an approach to increase the TBWP of the LFM signal generated by polarization modulation is proposed and comprehensively studied by splitting the electrical parabolic waveforms into N pieces with identical amplitude. Applying the split parabolic signal to the PolM, the total equivalent phase shift would be boosted by N/2 times. As a result, the bandwidth as well as the TBWP of the generated LFM signal is increased by N/2 times. An experiment is carried out. As compared to the scheme using an unsplit parabolic signal, the TBWP is improved by more than 500 times. The relationships between the bandwidth, the time duration, and the TBWP of the generated signal with the parameters of the electrical waveform generator are discussed.
Auteurs: Yamei Zhang;Xingwei Ye;Qingshui Guo;Fangzheng Zhang;Shilong Pan;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1821 - 1829
Editeur: IEEE
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» Physical Visualization of Geospatial Datasets
Résumé:
Geospatial datasets are too complex to easily visualize and understand on a computer screen. Combining digital fabrication with a discrete global grid system (DGGS) can produce physical models of the Earth for visualizing multiresolution geospatial datasets. This proposed approach includes a mechanism for attaching a set of 3D printed segments to produce a scalable model of the Earth. The authors have produced two models that support the attachment of different datasets both in 2D and 3D format.
Auteurs: Hessam Djavaherpour;Ali Mahdavi-Amiri;Faramarz F. Samavati;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 61 - 69
Editeur: IEEE
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» Physically Based Model for Multispectral Image Simulation of Earth Observation Sensors
Résumé:
Physically based multispectral image simulation consists of sensor system modeling, bottom-of-atmosphere (BOA) image generation, and top-of-atmosphere (TOA) image calculation. TOA radiance images are usually generated using a lookup table (LUT) for computational efficiency, which is calculated by means of atmospheric radiative transfer codes with different combination of input variables, including viewing zenith, solar zenith, and relative azimuth angles; visibility; columnar water vapor; and ground elevation. In this paper, a new strategy is proposed for TOA radiance image simulation, where transmitted surface radiance and atmospheric radiance at the TOA are calculated, respectively, to improve accuracy as well as efficiency. The transmitted surface radiance image is obtained from pixel-by-pixel calculation of BOA radiance and path transmittance. In calculating the atmospheric radiance of TOA, two LUTs are built for the emitted and the scattered radiance from each atmospheric layer, respectively. The effects of visibility and columnar water vapor on the atmospheric radiance are characterized by means of an equivalent path transmittance, which is related to the scene geometry as well as the thickness of atmospheric layer. In this way, when a new scene is simulated, except for three variables, i.e., viewing and solar zenith angles and atmospheric layer number, other parameters are set as constants in building the LUTs, enabling more combinations of input variables without adding excessive computational burden. Multispectral images in different bands with moderate spatial resolution are simulated and compared with the moderate-resolution imaging spectroradiometer (MODIS) images to demonstrate the accuracy and the usefulness of the proposed strategy.
Auteurs: Xiaoyu He;Xiaojian Xu;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1897 - 1908
Editeur: IEEE
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» Planar Wideband Differential-Mode Bandpass Filter With Common-Mode Noise Absorption
Résumé:
In this letter, a planar differential-mode (DM) four-port circuit is proposed to design a balanced-to-balanced bandpass filter (BPF) with common-mode noise absorption add-on feature. By using the matrix transformation between the mixed and the single-ended scattering parameters, even- (odd-) mode equivalent circuit and the closed-form solutions of the proposed circuit structure are obtained based on the constraint rules. Finally, a microstrip DM BPF is designed and fabricated. The measured (simulated) results show that the relative bandwidth is 55.5% (57.5%) under the conditions of $vert S_{mathbf {ddBA}}vert > -1$ dB and $vert S_{mathbf {ddAA}}vert $ , $vert S_{mathbf {ccAA}}vert $ , and $vert S_{mathbf {ccBA}}vert < -10$ dB. Good agreements between the simulated and measured results verify the correctness of the design theory.
Auteurs: Weiwei Zhang;Yongle Wu;Yuanan Liu;Cuiping Yu;Abul Hasan;Fadhel M. Ghannouchi;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 458 - 460
Editeur: IEEE
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» Planar-Nanostrip-Channel InAlN/GaN HEMTs on Si With Improved ${g}_{{m}}$ and ${f}_{textsf {T}}$ Linearity
Résumé:
In this letter, we report an InAlN/GaN high electron mobility transistor (HEMT) with a planar nanostrip channel design to improve its transconductance $text{g}_{mathrm {mathbf {textsf {m}}}}$ and cut-off frequency $text{f}_{mathbf {textsf {T}}}$ linearity. The planar nanostrips were formed by partial arsenic ion implantation isolation in the channel under the gate. Devices with a gate length ( $text{L}_{{textbf {g}}}$ ) of 80 nm and a source-to-drain distance ( $text{L}_{mathrm {mathbf {textsf {sd}}}}$ ) of 1 $mu text{m}$ were fabricated. A conventional device and a device with a fin-like nanowire channel were also fabricated together for comparison. It was observed that the nanostrip and nanowire channel structures can both suppress the access resistance increase at the high output current level, and thereby improve the device’s $text{g}_{mathrm {mathbf {textsf {m}}}}$ and $text{f}_{mathrm {mathbf {textsf {T}}}}$ linearity. Compared to the one using etching to form a fin-like nanostrip channel, the GaN HEMT with a planar nanostrip channel has demonstrated reduced parasitic capacitance and improved RF performance.
Auteurs: Weichuan Xing;Zhihong Liu;Haodong Qiu;Geok Ing Ng;Tomás Palacios;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 619 - 622
Editeur: IEEE
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» Plane Wave Scattering by a Conducting Cylinder Located Near an Interface Between Two Dielectric Half-Spaces: A Perturbation Method
Résumé:
A new and simple method is presented for transverse electric and transverse magnetic plane waves scattering by a perfectly conducting cylinder located near two-media interface. A particular formulation of the surface equivalence principle is employed to form a set of coupled integral equations by considering the interface as a scatterer. In this method, the infinite planar interface is represented by a single equivalent magnetic current which is expressed in terms of the difference in current with cylinder present and the exact solution with cylinder removed. Data for the induced current, near and far field are compared to the results available in the literature for verification.
Auteurs: Cengiz Ozzaim;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2754 - 2758
Editeur: IEEE
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» Planning of Renewable Generation in Distribution Systems Considering Daily Operating Periods
Résumé:
This paper presents an optimization approach for planning of renewable generation in energy distribution systems. The considered generations are based on wind turbines and photovoltaic panels. The objective is to determine the optimal placement of the renewable distributed generation aiming at minimizing the investment and operational costs in a long term planning. The proposed approach represents the stochastic behavior of the renewable resources by handling historical data to determine the wind and photovoltaic capacity factors. The method for obtaining such factors considers the daily load periods, which allows representing the availability of the energetic resources in different periods. The optimization method is based on the bioinspired metaheuristic known as artificial immune system. Two systems of the literature and practical wind and solar data from Brazil are used to assess the proposed approach.
Auteurs: Leonardo Willer Oliveira;Thaisy Cristina Jose Maria;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 901 - 907
Editeur: IEEE
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» PlenoPatch: Patch-Based Plenoptic Image Manipulation
Résumé:
Patch-based image synthesis methods have been successfully applied for various editing tasks on still images, videos and stereo pairs. In this work we extend patch-based synthesis to plenoptic images captured by consumer-level lenselet-based devices for interactive, efficient light field editing. In our method the light field is represented as a set of images captured from different viewpoints. We decompose the central view into different depth layers, and present it to the user for specifying the editing goals. Given an editing task, our method performs patch-based image synthesis on all affected layers of the central view, and then propagates the edits to all other views. Interaction is done through a conventional 2D image editing user interface that is familiar to novice users. Our method correctly handles object boundary occlusion with semi-transparency, thus can generate more realistic results than previous methods. We demonstrate compelling results on a wide range of applications such as hole-filling, object reshuffling and resizing, changing object depth, light field upscaling and parallax magnification.
Auteurs: Fang-Lue Zhang;Jue Wang;Eli Shechtman;Zi-Ye Zhou;Jia-Xin Shi;Shi-Min Hu;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1561 - 1573
Editeur: IEEE
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» Plug-In Electric Vehicles Parking Lot Equilibria With Energy and Reserve Markets
Résumé:
This paper proposes a comprehensive model for the interactions of the plug-in electric vehicles (PEVs) involved parties. An aggregator with mixed resources is assumed to be the interface between the parking lot (PL) and the upstream energy and reserve markets. On the other hand, the interactions of the PEV owners and the PL are also modeled as they impose restrictions to the PL's behavior. Therefore, a bilevel problem is constructed where in the upper level the objective of the aggregator is to maximize its profit through its interactions, and in the lower level the PL maximizes its own profit limited to the preferences of PEVs. The objectives of the upper and lower levels are contradictory; hence, an equilibrium point should be found to solve the problem. In this regard, the duality theorem is employed to convert the bilevel model to a mathematical program with equilibrium constraints. The model is implemented on the IEEE 37-bus network with added distributed generations. Various cases are thoroughly investigated and conclusions are duly drawn.
Auteurs: Nilufar Neyestani;Maziar Yazdani Damavandi;Miadreza Shafie-khah;Anastasios G. Bakirtzis;João P. S. Catalão;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2001 - 2016
Editeur: IEEE
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» Plug-in Free Web-Based 3-D Interactive Laboratory for Control Engineering Education
Résumé:
This paper introduces the design and implementation of a plug-in free online 3-D interactive laboratory based on networked control system laboratory (NCSLab) framework. The system relying only on HTML5 provides full supports for control engineering experimentation. The users are allowed to design their own control algorithms and apply them to the remote test rigs. Using the web-based interface, multiple widgets such as real-time charts, virtual gauges, and live images are available to customize the monitoring interfaces. To enhance the sense of immersion, 3-D animations which are synchronized with the remote experimental processes are also provided. The users can watch and interact with the remote experiments through the 3-D replicas. Various HTML5 based toolkits are integrated seamlessly under the NCSLab framework. NCSLab provides visualized services for the whole process of control experimentation including remote monitoring, tuning, configuration, and control algorithm implementation. As the network delay could disturb the 3-D representation, a communication scheme using web protocols is also implemented. The feedback from teaching shows the general acceptance and effectiveness of NCSLab is notably high. As most existing online laboratories adopt either native applications or plug-ins, the methodologies and technologies used in NCSLab could be insightful for other online laboratories toward web-based cross-platform systems.
Auteurs: Wenshan Hu;Zhongcheng Lei;Hong Zhou;Guo-Ping Liu;Qijun Deng;Dongguo Zhou;Zhi-Wei Liu;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3808 - 3818
Editeur: IEEE
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» PMCC: Fast and Accurate System-Level Power Modeling for Processors on Heterogeneous SoC
Résumé:
Accurate estimation of power at the system level is essential for system-on-chip (SoC) architects. The integration of heterogeneous processors like CPUs and emerging coarse-grained reconfigurable architectures (CGRAs) in SoCs significantly complicates the power-estimation process. This brief presents an accurate and efficient system-level power modeling framework, power modeling with a customized calibration, for processors on heterogeneous SoCs. Quantitative criteria are developed to classify the computing resources of heterogeneous SoCs, including instruction-driven processing architectures and CGRAs-based architectures, into two categories automatically. A novel power-modeling technique featuring a genetic algorithm and backpropagation neural network (GA-BPNN) is introduced to address CGRA-alike architectures, which cannot be properly handled by the traditional linear regression-based power calibration method. Experimental results show that the power estimation error for CGRAs using GA-BPNN is less than 5% with three orders faster speed compared with gate-level estimations. In the meanwhile, accuracy is improved on most benchmarks compared with the linear model. The average improvement in accuracy is 81% and ranges between 29% and 99%.
Auteurs: Chenchen Deng;Leibo Liu;Yang Liu;Shouyi Yin;Shaojun Wei;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 540 - 544
Editeur: IEEE
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» Polarization-Dependent Optical Sensor Based on Reduced Graphene Oxide
Résumé:
We report a polarization-dependent optical sensor based on reduced graphene oxide (rGO) and demonstrate its applications in detecting refractive indices. The s-polarized absorption of the rGO under the conditions of total internal reflection is unique over the range of 400–1100 nm and its amplitude is sensitive to the media that is in contact with the rGO. We have conducted detailed calculations and experiments to optimize the performance of the sensor. The sensitivity of the optical sensor is $3.10~Delta $ R/RIU and its resolution is $9.7times 10 ^{-4}$ RIU.
Auteurs: Guohua Liu;Jun Yu;Lixia Xie;Zheng Dou;Wei Zhang;Zhao Yue;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 767 - 770
Editeur: IEEE
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» Polarization-Independent Backscattering Enhancement of Cylinders Based on Conformal Gradient Metasurfaces
Résumé:
The electromagnetic backscattering enhancement of both elliptic and circular conducting cylinders is investigated in this paper through the design of conformal and polarization-independent gradient metasurfaces. The presented metasurface designs employ varying phase gradient along the circumferential direction of the involved cylinder so that effective retroreflection can be achieved through redirecting the scattering dispersed by the conducting cylinder back to the direction from which the plane electromagnetic wave is coming. Supported by a grounded thin substrate with a relatively high dielectric constant, a modified loop array with compact unit cell is used to implement the nonuniformly or uniformly sampled phase gradient of the metasurface. It is observed that the metasurface-coated elliptic and circular cylinders can generate backscattering very close to that by corresponding flat conducting plates with their main planes perpendicular to the incident wave vector, for both transverse magnetic (TM) and transverse electric (TE) polarizations. Compared with the conducting cylinders without coating, the backscattering is thus effectively enhanced by the conformal gradient metasurfaces. Good agreement between simulated and measured backscattering results validates the observations.
Auteurs: Yuping Shang;Zhongxiang Shen;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2386 - 2396
Editeur: IEEE
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» Polling and Prediction in the 2016 Presidential Election
Résumé:
In the wake of experts' failure to predict the outcome of the 2016 presidential election, a rigorous analysis of what went right and wrong is needed to improve future polling. Despite claims that "data is dead," low-tech factors such as sampling errors and inaccurate likely-voter models were probably most responsible.
Auteurs: Nicholas A. Valentino;John Leslie King;Walter W. Hill;
Apparue dans: Computer
Date publication: 05.-2017, volume: 50, issue:5, pages: 110 - 115
Editeur: IEEE
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» Portable Luminescence Based Fiber Optic Probe for REE Detection and Quantification
Résumé:
A novel luminescence-based sensor was developed for the rapid, insitu detection and quantification of rare earth elements for potential applications in waste recovery. The device has the capability to detect $mu text{g}$ /L (part-per billion) concentrations of several rare earths in aqueous solution within 1 min, and it is portable given a physical dimension of less than 1/2 m3. Whereas, conventional table-top devices used for this type of analysis are bulky and have high costs, in addition to the typical two week long processing times for laboratory analyses of rare earths. The rapid return of results that this portable and rugged device provides can save the end user the cost of inaction during recovery or mining operations, potentially allowing for “in line” monitoring or rapid field sampling. Luminescence sensitizers were used to lower the limit of detection of the rare earths in comparison with direct excitation, by approximately an order of magnitude. Examples of luminescence sensitizers tested include M(CN)2 (where M = Ag, Au, Cu) and 2,2 bipyridine.
Auteurs: John C. Ahern;Zsolt L. Poole;John Baltrus;Paul R. Ohodnicki;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2644 - 2648
Editeur: IEEE
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» Postearthquake Landslides Mapping From Landsat-8 Data for the 2015 Nepal Earthquake Using a Pixel-Based Change Detection Method
Résumé:
The 2015 Nepal earthquake and its aftershocks not only caused huge damage with severe loss of life and property, also induced many geohazards with the major type of landslide which should bring continuous threats to the affected region. To gain a better understanding of the landslides induced by this earthquake, we proposed a pixel-based change detection method for postearthquake landslide mapping by using bitemporal Landsat-8 remote sensing data [May 29, 2014 (pre-earthquake) and June 1, 2015 (postearthquake)]. Two river valleys (Trishuli river valley and Sun Koshi river valley) that contain important economic arteries linking Nepal and China were selected as the study areas. Validation of the mapping results with postearthquake high-resolution images from Google Earth shows that the pixel-based landslide mapping method is able to identify landslides with relatively high accuracy, and it also approves the applicability of Landsat-8 satellite for landslide mapping with its multispectral information. The spatial distribution analysis indicates that both river valleys are substantially affected by landslides, and the situation is even more serious in the high mountain areas. Landslides are generally found in areas of high elevation and large surface slopes, with mean values above 1600 m and 30°, respectively. These findings suggest that these areas suffer greatly from these geohazards, and the threat will continue for the next few years.
Auteurs: Wei Zhao;Ainong Li;Xi Nan;Zhengjian Zhang;Guangbin Lei;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1758 - 1768
Editeur: IEEE
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» Pothole in the Dark: Perceiving Pothole Profiles with Participatory Urban Vehicles
Résumé:
Accessing to timely and accurate road condition information, especially about dangerous potholes is of great importance to the public and the government. In this paper, we propose a novel scheme, called $P^3$ , which utilizes smartphones placed in normal vehicles to sense and estimate the profiles of potholes on urban surface roads. In particular, a $P^3$ -enabled smartphone can actively learn the knowledge about the suspension system of the host vehicle without any human intervention and adopts a one degree-of-freedom (DOF) vibration model to infer the depth and length of pothole while the vehicle is hitting the pothole. Furthermore, $P^3$ shows the potential to derive more accurate results by aggregating individual estimates. In essence, $P^3$ is light-weighted and robust to various conditions such as poor light, bad weather, and different vehicle types. We have implemented a prototype system to prove the practical feasibility of $P^3$ . The results of extensive experiments based on real trace demonstrate the efficacy of the $P^3$ design. On average, $P^3$ can achieve low depth and length estimation error rates of 13 and 16 percent, respectively.
Auteurs: Guangtao Xue;Hongzi Zhu;Zhenxian Hu;Jiadi Yu;Yanmin Zhu;Yuan Luo;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1408 - 1419
Editeur: IEEE
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» Power Management Comparison for a Dual-Motor-Propulsion System Used in a Battery Electric Bus
Résumé:
The efficiency performance of multi-motor-driven system highly depends on the power management. Three aspects of contribution have been made in this study. 1) A predictive power management for a DMPS is developed. To improve the performance of the predictive power management, an adaptive velocity predictor is proposed and the coefficients of proposed predictor can update its parameters according to identified driving patterns. Simulation results show that the new velocity predictor have best prediction performance compared with traditional predictors. 2) A neural network based power management is proposed. According to the optimization results of dynamic programming, radial-basis-function neural network is trained. The input dimensions and the number of hidden layer neurons of the neural network are optimized. 3) The performance of proposed control strategies are compared with three different drive cycles including MANHATTAN cycle, Japanese 1015 cycle, and UDDSHDV cycle. Simulation results indicate that compared with original control strategy, the predictive control strategy and neural network based control strategy show better efficiency performance. The neural network based strategy is verified by hardware-in-loop experiment and experiment results indicate that the control performance in real hardware shows similar property with simulation results.
Auteurs: Chengning Zhang;Shuo Zhang;Guangwei Han;Haipeng Liu;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3873 - 3882
Editeur: IEEE
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» Power Spectral Density of Magnetization Dynamics Driven by a Jump-Noise Process
Résumé:
Random magnetization dynamics driven by a jump-noise process is reduced to stochastic magnetic energy dynamics on specific graphs using an averaging technique. An approach to analyzing stochastic energy dynamics on graphs is presented and applied to the calculation of power spectral density of random magnetization dynamics. An eigenvalue technique for computing the power spectral density under specific cases is also presented and illustrated by numerical results.
Auteurs: A. Lee;G. Bertotti;C. Serpico;I. Mayergoyz;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 5
Editeur: IEEE
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» Power System State and Transmission Line Conductor Temperature Estimation
Résumé:
This paper presents a state estimation technique for three-phase power systems where not only bus voltage phasors but also the temperature of transmission line conductors is considered as states. Transmission line admittance parameters depending on line conductor and ambient temperature are approximated from the pre-computed data based on polynomial interpolations. Weather environment and heat-balance equations have been also included in the measurement functions in order to estimate the temperature of conductors. The technique for segmenting transmission lines is also applied for handling temperature variations along the lines. The estimation problem is then formulated as a constrained nonlinear optimization based on the weighted least-squares criterion. A solution is obtained by applying a predictor–corrector interior point algorithm. Simulation results on some three-phase power systems indicate that the proposed method yields estimations with a better accuracy.
Auteurs: Chawasak Rakpenthai;Sermsak Uatrongjit;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1818 - 1827
Editeur: IEEE
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» Practical Opportunistic Data Collection in Wireless Sensor Networks with Mobile Sinks
Résumé:
Wireless Sensor Networks with Mobile Sinks (WSN-MSs) are considered a viable alternative to the heavy cost of deployment of traditional wireless sensing infrastructures at scale. However, current state-of-the-art approaches perform poorly in practice due to their requirement of mobility prediction and specific assumptions on network topology. In this paper, we focus on low-delay and high-throughput opportunistic data collection in WSN-MSs with general network topologies and arbitrary numbers of mobile sinks. We first propose a novel routing metric, Contact-Aware ETX (CA-ETX), to estimate the packet transmission delay caused by both packet retransmissions and intermittent connectivity. By implementing CA-ETX in the defacto TinyOS routing standard CTP and the IETF IPv6 routing protocol RPL, we demonstrate that CA-ETX can work seamlessly with ETX. This means that current ETX-based routing protocols for static WSNs can be easily extended to WSN-MSs with minimal modification by using CA-ETX. Further, by combing CA-ETX with the dynamic backpressure routing, we present a throughput-optimal scheme Opportunistic Backpressure Collection (OBC). Both CA-ETX and OBC are lightweight, easy to implement, and require no mobility prediction. Through test-bed experiments and extensive simulations, we show that the proposed schemes significantly outperform current approaches in terms of packet transmission delay, communication overhead, storage overheads, reliability, and scalability.
Auteurs: Shusen Yang;Usman Adeel;Yad Tahir;Julie A. McCann;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1420 - 1433
Editeur: IEEE
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» Precise Position Synchronous Control for Multi-Axis Servo Systems
Résumé:
This paper presents a general solution of precise position synchronous control for multi-axis servo systems. The control strategy to achieve high-precision motion is summarized in two main points: an adaptive-fuzzy friction compensator is adopted in the independent control loop of each axis to compensate the nonlinear friction, and then a method which combines global sliding mode control with two adjacent axes cross-coupling technology is proposed to minimize not only single-axis position error but also synchronous errors of all motion axes. At first, the adaptive fuzzy algorithm including dynamic model of the system is utilized to design a friction compensation controller. Next, to improve robustness of the multi-axis motion system against variation of motor parameters and external disturbances, global sliding mode control is introduced. In addition, the multi-axis synchronous control based on cross-coupling technology is elaborately designed via proportional-differential control law. The performance of the proposed control system is investigated through extensive simulations based on a popular motion platform. Furthermore, experimental study shows that the results successfully demonstrate the effectiveness of the proposed position synchronous control method for a general four-axis servo system.
Auteurs: Guoliang Zhong;Zhizhong Shao;Hua Deng;Junli Ren;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3707 - 3717
Editeur: IEEE
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» Preconditioned Data Sparsification for Big Data With Applications to PCA and K-Means
Résumé:
We analyze a compression scheme for large data sets that randomly keeps a small percentage of the components of each data sample. The benefit is that the output is a sparse matrix, and therefore, subsequent processing, such as principal component analysis (PCA) or K-means, is significantly faster, especially in a distributed-data setting. Furthermore, the sampling is single-pass and applicable to streaming data. The sampling mechanism is a variant of previous methods proposed in the literature combined with a randomized preconditioning to smooth the data. We provide guarantees for PCA in terms of the covariance matrix, and guarantees for K-means in terms of the error in the center estimators at a given step. We present numerical evidence to show both that our bounds are nearly tight and that our algorithms provide a real benefit when applied to standard test data sets, as well as providing certain benefits over related sampling approaches.
Auteurs: Farhad Pourkamali-Anaraki;Stephen Becker;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2954 - 2974
Editeur: IEEE
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» Predicting Image Memorability Through Adaptive Transfer Learning From External Sources
Résumé:
Remembering images is an innate human capability. Camera images are captured by different people under varying environmental conditions, which leads to highly diverse image memorability scores. However, the factors that make an image more or less memorable are unclear, and it remains unknown how we can more accurately predict image memorability by using such factors. In this paper, we propose a novel framework called multiview transfer learning from external sources (MTLES) to predict image memorability. In this framework, we simultaneously leverage different types of visual feature sets and multiple types of predefined image attributes derived from external sources. In particular, to enhance representation ability of visual features, we construct connections between visual feature sets and higher level image attributes by transferring attribute knowledge from external sources. MTLES integrates weak learning through external sources, transfer learning, and multiview consistency loss with different types of feature sets into a joint framework. To better solve this joint optimization problem, we further develop an alternating iterative algorithm to deal with it. Experiments performed on the publicly available LaMem dataset demonstrate the effectiveness of the proposed scheme.
Auteurs: Peiguang Jing;Yuting Su;Liqiang Nie;Huimin Gu;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 05.-2017, volume: 19, issue:5, pages: 1050 - 1062
Editeur: IEEE
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» Preflight Spectral Calibration of the Orbiting Carbon Observatory 2
Résumé:
This paper describes the preflight spectral calibration methods and results for the Orbiting Carbon Observatory 2 (OCO-2), following the approach developed for the first OCO. The instrument line shape (ILS) function and dispersion parameters were determined through laser-based spectroscopic measurements, and then further optimized by comparing solar spectra recorded simultaneously on the ground by the OCO-2 flight instrument and a collocated high-resolution Fourier transform spectrometer (FTS). The resulting ILS profiles and dispersion parameters, when applied to the FTS solar data, showed agreement between the spectra recorded by the spectrometers and FTS to approximately 0.2% RMS, satisfying the preflight spectral calibration accuracy requirement of <;0.25% RMS. Specific changes to the OCO-2 instrument and calibration process, compared to the original OCO, include stray-light protection; improved laser setup; increased spectral sampling; enhanced data screening, and incremental improvements in the ILS, dispersion, and FTS optimization analyses.
Auteurs: Richard A. M. Lee;Christopher W. O’Dell;Debra Wunch;Coleen M. Roehl;Gregory B. Osterman;Jean-Francois Blavier;Robert Rosenberg;Lars Chapsky;Christian Frankenberg;Sarah L. Hunyadi-Lay;Brendan M. Fisher;David M. Rider;David Crisp;Randy Pollock;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2499 - 2508
Editeur: IEEE
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» Preserving Privacy with Probabilistic Indistinguishability in Weighted Social Networks
Résumé:
The increasing popularity of social networks has inspired recent research to explore social graphs for marketing and data mining. As social networks often contain sensitive information about individuals, preserving privacy when publishing social graphs becomes an important issue. In this paper, we consider the identity disclosure problem in releasing weighted social graphs. We identify weighted 1*-neighborhood attacks, which assume that an attacker has knowledge about not only a target's one-hop neighbors and connections between them (1-neighborhood graph), but also related node degrees and edge weights. With this information, an attacker may re-identify a target with high confidence, even if any node's 1-neighborhood graph is isomorphic with $k-1$ other nodes’ graphs. To counter this attack while preserving high utility of the published graph, we define a key privacy property, probabilistic indistinguishability, and propose a heuristic indistinguishable group anonymization (HIGA) scheme to anonymize a weighted social graph with such a property. Extensive experiments on both real and synthetic data sets illustrate the effectiveness and efficiency of the proposed scheme.
Auteurs: Qin Liu;Guojun Wang;Feng Li;Shuhui Yang;Jie Wu;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1417 - 1429
Editeur: IEEE
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» Preserving Synchronization Accuracy From the Plug-in of NonSynchronized Nodes in a Wireless Sensor Network
Résumé:
The synchronization accuracy of the nodes of a wireless sensor network (WSN) can be perturbed by the plug-in of nonsynchronized nodes (NSNs). In the case of peer-to-peer synchronization algorithms, the reference time of the WSN is established on the basis of the clock time of all nodes. Therefore, each NSN changes the reference time to synchronize all nodes with the new reference time interval needs. In this time interval, the synchronization accuracy can degrade, i.e., the delay among node clocks overcomes the admissible range. In the case of only one or many NSNs, it was assessed in previous papers that by filtering the message of each NSN, the synchronization accuracy of the already synchronized nodes (ASNs) is preserved. However, the spatial distribution of the NSNs can fool the ASNs, foiling the effect of the message filtering. This paper presents a procedure that overcomes this inconvenience. The new fully distributed and consensus-based procedure iteratively filters the messages of communicating NSNs that would increase the time delay over the admissible range. As a consequence, the synchronization accuracy is preserved whatever the spatial distribution of ASNs and NSNs. Numerical and experimental tests are performed to validate the proposed procedure.
Auteurs: Francesco Lamonaca;Domenico Luca Carnì;Maria Riccio;Domenico Grimaldi;Gregorio Andria;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 1058 - 1066
Editeur: IEEE
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» Printed Motes for IoT Wireless Networks: State of the Art, Challenges, and Outlooks
Résumé:
Although wireless sensor networks (WSNs) have been an active field of research for many years, the modules incorporated by WSN nodes have been mainly manufactured utilizing conventional fabrication techniques that are mostly subtractive, requiring significant amounts of materials and increased chemical waste. The new era of the Internet of Things (IoT) will see the fabrication of numerous small form factor devices for wireless sensing for a plurality of applications, including security, health, and environmental monitoring. The large volume of these devices will require new directions in terms of manufacturing cost and energy efficiency, which will be achieved with redesigned, energy-aware modules. This paper presents the state of the art of printed passives, sensors, energy harvesting modules, actives, and communication front ends, and summarizes the challenges of implementing modules that feature low power consumptions without compromising the low fabrication cost. The plethora of the modules presented herein will facilitate the implementation of low cost, additively manufactured, energy-aware IoT nodes that can be fabricated in large volumes with green processes.
Auteurs: Jimmy G. D. Hester;John Kimionis;Manos M. Tentzeris;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1819 - 1830
Editeur: IEEE
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» Printed Organic Circuits for Reading Ferroelectric Rewritable Memory Capacitors
Résumé:
We demonstrate an inkjet-printed organic thin-film transistor (OTFT) circuit for reading ferroelectric (FE) nonvolatile rewritable memories. With the large difference in polarization charge between FE memory states, we implement a single-OTFT gain stage with latch and show that a gain of −2.8 is sufficient to distinguish memory states. This paper evaluates the effect of device variations on the yield of this readout circuit.
Auteurs: Tse Nga Ng;David E. Schwartz;Ping Mei;Sivkheng Kor;Janos Veres;Per Bröms;Christer Karlsson;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 1981 - 1984
Editeur: IEEE
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» Privacy Preserving Cloth Try-On Using Mobile Augmented Reality
Résumé:
Virtual try-on applications make it possible for buyers to watch themselves wearing different garments without physically trying on them. The prevailing approach for virtual try-on has been based on virtual fitting rooms, in which several cameras are used to identify the skeleton and posture of a user in order to render a garment on the user's image. Although this approach has been implemented successfully using different techniques, the privacy of users can be compromised as some users might be reluctant to stand in front of cameras in a fitting room. This paper proposes an alternative approach that allows a customer to watch a three-dimensional (3D) model of her/him wearing garments on a personal mobile device using augmented reality (AR). Among 3D human models that are automatically generated, a model selection technique is proposed that makes it possible to find the right size model representing the anthropometric features of the user. This approach is accompanied by body customization and face generation modules to generate a realistic representation. Several quantitative experiments as well as user studies were performed to evaluate the accuracy, efficiency, usefulness, and privacy of the proposed technique.
Auteurs: Yoones A. Sekhavat;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 05.-2017, volume: 19, issue:5, pages: 1041 - 1049
Editeur: IEEE
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» Proactive Eavesdropping via Cognitive Jamming in Fading Channels
Résumé:
To enhance the national security, there is a growing need for authorized parties to legitimately monitor suspicious communication links for preventing intended crimes and terror attacks. In this paper, we propose a new wireless information surveillance paradigm by investigating a scenario, where a legitimate monitor aims to intercept a suspicious wireless link over fading channels. The legitimate monitor can successfully eavesdrop (decode) the information of the suspicious link at each fading state only when its achievable data rate is no smaller than that at the suspicious receiver. We propose a new approach, namely, proactive eavesdropping via cognitive jamming, in which the legitimate monitor purposely jams the receiver in a full-duplex mode so as to change the suspicious communication (e.g., to a smaller data rate) for overhearing more efficiently. By assuming perfect self-interference cancelation (SIC) and global channel state information (CSI) at the legitimate monitor, we characterize the fundamental information-theoretic limits of proactive eavesdropping. We consider both delay-sensitive and delay-tolerant applications for the suspicious communication, under which the legitimate monitor maximizes the eavesdropping non-outage probability (for event-based monitoring) and the relative eavesdropping rate (for content analysis), respectively, by optimizing the jamming power allocation over different fading states subject to an average power constraint. Numerical results show that the proposed proactive eavesdropping via cognitive jamming approach greatly outperforms other benchmark schemes. Furthermore, by extending to a more practical scenario with residual SI and local CSI, we design an efficient online cognitive jamming scheme inspired by the optimal cognitive jamming with perfect SIC and global CSI.
Auteurs: Jie Xu;Lingjie Duan;Rui Zhang;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2790 - 2806
Editeur: IEEE
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» Probabilistic Equalization With a Smoothing Expectation Propagation Approach
Résumé:
In this paper, we face the soft equalization of channels with inter-symbol interference for large constellation sizes, $ mathtt {M}$ . In this scenario, the optimal BCJR solution and most of their approximations are intractable, as the number of states they track grows fast with $ mathtt {M}$ . We present a probabilistic equalizer to approximate the posterior distributions of the transmitted symbols using the expectation propagation (EP) algorithm. The solution is presented as a recursive sliding window approach to ensure that the computational complexity is linear with the length of the frame. The estimations can be further improved with a forward–backward approach. This novel soft equalizer, denoted as smoothing EP (SEP), is also tested as a turbo equalizer, with a low-density parity-check (LDPC) channel decoder. The extensive results reported reveal remarkably good behavior of the SEP. In low dimensional cases, the bit error rate (BER) curves after decoding are closer than 1 dB from those of the BJCR, robust to the channel response. For large $ mathtt {M}$ , the SEP exhibits gains in the range of 3–5 dB compared to the linear minimum mean square error algorithm.
Auteurs: Irene Santos;Juan José Murillo-Fuentes;Eva Arias-de-Reyna;Pablo M. Olmos;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2950 - 2962
Editeur: IEEE
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» Probabilistic Forecasting of Photovoltaic Generation: An Efficient Statistical Approach
Résumé:
A novel efficient probabilistic forecasting approach is proposed to accurately quantify the variability and uncertainty of the power production from photovoltaic (PV) systems. Distinguished from most existing models, a linear programming-based prediction interval construction model for PV power generation is established based on an extreme learning machine and quantile regression, featuring high reliability and computational efficiency. The proposed approach is validated through the numerical studies on PV data from Denmark.
Auteurs: Can Wan;Jin Lin;Yonghua Song;Zhao Xu;Guangya Yang;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2471 - 2472
Editeur: IEEE
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» Process Monitoring for Multimodal Processes With Mode-Reachability Constraints
Résumé:
For increased efficiency and profitability, many processes have multiple modes of operation. Switching between different operating modes is performed according to the standard operating procedures. These procedures are set by considering safety and operating limitations of various subsystems and equipment, and thus put restrictions on the switching of the process modes. In this paper, a hidden Markov model based monitoring method is proposed that can not only handle the multimodality of process data but can also capture the mode switching restrictions. A two-step Viterbi algorithm is proposed for effective mode detection in the event of faults, and a reconstruction-based fault isolation algorithm is developed to build the contribution plots. Application examples demonstrate the effectiveness of the proposed monitoring method.
Auteurs: Muhammad Shahzad Afzal;Wen Tan;Tongwen Chen;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4325 - 4335
Editeur: IEEE
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» Process Variation Analysis and Optimization of a FinFET-Based VCO
Résumé:
Fin-type field-effect transistors (FinFETs) are promising substitutes for bulk CMOS for nanoscale technologies. In this paper, the viability of a mixed-signal design for FinFET-based technologies using a nanoscale current-starved voltage controlled oscillator (VCO) is investigated. Design issues are analyzed and a comparison between a CMOS VCO and a FinFET-based VCO is presented. The figures-of-merit used for comparison are center frequency and frequency–voltage ( ${f}$ ${V}$ ) characteristics under process variation. Models are developed for the ${f}$ ${V}$ characteristics of both the CMOS and FinFET VCOs. In addition, width quantization-aware modeling has been performed for the FinFET-based VCO using a polynomial metamodel, which can be used for further optimization. The quantization aware modeling is highly accurate as evident from a correlation coefficient ${R^{2}}$ of 0.999 and root mean square error of 6.2 MHz. The FinFET VCO has $5.5 {times }$ faster oscillation frequency with 2.6% variability as opposed to 19.7% for the CMOS VCO. To the best of the authors’ knowledge, this is the first paper that examines FinFET technology with respect to process variation in mixed signal designs at the circuit level, and presents a quantitative as well as qualitative comparison between CMOS and FinFET technologies.
Auteurs: Venkata P. Yanambaka;Saraju P. Mohanty;Elias Kougianos;Dhruva Ghai;Garima Ghai;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 05.-2017, volume: 30, issue:2, pages: 126 - 134
Editeur: IEEE
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» Processing Sliding Mosaic Mode Data With Modified Full-Aperture Imaging Algorithm Integrating Scalloping Correction
Résumé:
Modified full-aperture imaging algorithm for sliding Mosaic mode synthetic aperture radar (SAR) is presented in this paper, which includes scalloping correction and spikes suppression. The full-aperture imaging algorithm is introduced into Mosaic mode and validated by real C-band airborne SAR imaging experiments. The main idea is to substitute zeros between bursts with linear-predicted data extrapolated from adjacent bursts to suppress the spikes caused by multibursts processing. Furthermore, scalloping correction for sliding Mosaic mode is integrated with this algorithm. It is innovational to correct the azimuth beam pattern weighting altered by radar antenna rotation in azimuth with deramping preprocessing operation. Finally, experiments performed by the C-band airborne SAR system with a maximum bandwidth of 200 MHz validate the effectiveness of the approach.
Auteurs: Ning Li;Robert Wang;Yunkai Deng;Tuan Zhao;Wei Wang;Heng Zhang;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1804 - 1812
Editeur: IEEE
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» Profile: enviro power - This company is bringing microcogeneration to the U.S. [Resources_Startups]
Résumé:
Cogeneration, or combined heat and power (CHP), is the simultaneous production of electricity and useful heat. The global market for cogeneration equipment could hit US $43.8 billion by 2020, according to market research firm Global Industry Analysts. Cogeneration is often associated with large power plants in North America, and few there have modified the technology for small-scale commercial use. And nobody is selling a microcogeneration unit in the United States that is affordable enough for the average single-family house.
Auteurs: Theresa Sullivan Barger;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 22 - 22
Editeur: IEEE
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» Progress Overview of Capturing Method for Integral 3-D Imaging Displays
Résumé:
An integral 3-D technique provides a 3-D spatial image viewable from varying positions without the use of special light sources or viewing glasses. Therefore, this technique shows promise for diverse applications in various fields, including 3-D television broadcasting, advertising, and medical diagnostics. However, there are problems in capturing and displaying large amounts of information in realizing practical integral imaging devices. This paper overviews integral 3-D capturing methods and analyzes integral 3-D imaging technology at its capturing and displaying stages. To overcome the resolution problem, it also introduces our recent work for capturing high-resolution integral imaging information. The introduced device consists of a multiple-lens array and a complementary metal–oxide–semiconductor image sensor with a circuit patterned using multiple exposures. This device can capture depth-controlled spatial information by introducing additional optics. Two types of optics for depth control are applied to the capturing device: one functions as a convex lens to control and compress a relatively large object space and the other functions as an afocal lens array that controls a relatively small object space without any distortion in the depthwise direction. Experimental results of spatial information capturing and 3-D image displays confirm that the method produces 3-D images having an appropriate motion parallax. The presented method is scalable; thus, this technique offers possibilities for developing advanced high-resolution integral 3-D imaging devices.
Auteurs: Jun Arai;Eisuke Nakasu;Takayuki Yamashita;Hitoshi Hiura;Masato Miura;Tomohiro Nakamura;Ryohei Funatsu;
Apparue dans: Proceedings of the IEEE
Date publication: 05.-2017, volume: 105, issue:5, pages: 837 - 849
Editeur: IEEE
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» Properties of an Aloha-Like Stability Region
Résumé:
A well-known inner bound on the stability region of the finite-user slotted Aloha protocol is the set of all arrival rates for which there exists some choice of the contention probabilities such that the associated worst case service rate for each user exceeds the user’s arrival rate, denoted $Lambda $ . Although testing membership in $Lambda $ of a given arrival rate can be posed as a convex program, it is nonetheless of interest to understand the properties of this set. In this paper, we develop new results of this nature, including, 1) an equivalence between membership in $Lambda $ and the existence of a positive root of a given polynomial, 2) a method to construct a vector of contention probabilities to stabilize any stabilizable arrival rate vector, 3) the volume of $Lambda $ , 4) explicit polyhedral, spherical, and ellipsoid inner and outer bounds on $Lambda $ , and 5) characterization of the generalized convexity properties of a natural “excess rate” function associated with $Lambda $ , including the convexity of the set of contention probabilities that stabilize a given arrival rate vector.
Auteurs: Nan Xie;John MacLaren Walsh;Steven Weber;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3181 - 3208
Editeur: IEEE
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» Proportional Fairness-Based Beamforming and Signal Splitting for MISO-SWIPT Systems
Résumé:
The problem of proportional fairness-based beamforming and power splitting is investigated for simultaneous wireless information and power transferring systems. Due to the non-convexity of the formulated problem, a suboptimal solution is proposed based on the classical zero-forcing beamforming (ZFBF) and maximal ratio transmission techniques. To overcome the limitation of the ZFBF technique, a successive approximation-based algorithm is proposed. Simulation results verify the effectiveness of the proposed algorithms.
Auteurs: Yanjie Dong;Xin Ge;Jahangir Hossain;Julian Cheng;Victor C. M. Leung;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1135 - 1138
Editeur: IEEE
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» Pt-AlGaN/GaN Hydrogen Sensor With Water-Blocking PMMA Layer
Résumé:
One of the biggest issues with GaN-based hydrogen sensors is their sensitivity to humidity in the ambient. We demonstrate that encapsulation of Pt-AlGaN/GaN Schottky diode with poly(methyl methacrylate) (PMMA) provides effective mitigation of the effects of water. Without PMMA encapsulation, the absolute current signal for detection of 500 ppm of H2 was decreased by a factor of 8 in the presence of water. By sharp contrast, encapsulated diodes show no decrease in response in the presence of water. The relative current changes are of the order $2.8 times 10^{5}$ % when 500 ppm H2 is introduced to the surface of bare or PMMA encapsulated diodes in the absence of water or to encapsulated diode in the presence of water. Detection limits of ~ 100 ppm H2 (0.01% by volume) were obtained with standard forward bias detection mode at 1.3 V.
Auteurs: Sunwoo Jung;Kwang Hyeon Baik;Fan Ren;Stephen J. Pearton;Soohwan Jang;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 657 - 660
Editeur: IEEE
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» Purchase Bidding Strategy for a Retailer With Flexible Demands in Day-Ahead Electricity Market
Résumé:
The paper aims to determine the day-ahead market bidding strategies for retailers with flexible demands to maximize the short-term profit. It proposes a short-term planning framework to forecast the load under dynamic tariffs and construct biding curves. Stochastic programming is applied to manage the uncertainties of spot price, regulating price, consumption behaviors, and responsiveness to dynamic tariffs. A case study based on data from Sweden is carried out. It demonstrates that a real-time selling price can affect the aggregate load of a residential consumer group and lead to load shift toward low-price periods. The optimal bidding curves for specific trading periods are illustrated. Through comparing the bidding strategies under different risk factors, the case study shows that a risk-averse retailer tends to adopt the strategies with larger imbalances. The benefit lies in the reduction of low-profit risk. However, the aversion to risk can only be kept in a certain level. A larger imbalance may lead to a quick reduction of profit in all scenarios.
Auteurs: Meng Song;Mikael Amelin;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1839 - 1850
Editeur: IEEE
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» QoE Enhanced Mobile Data Offloading With Balking
Résumé:
In this letter, we analyze the delayed mobile data offloading scheme by modeling it as an alternating regenerative process. We use a novel way for deriving transmission delay and offloading efficiency, by analyzing the stochastic process characterizing the virtual waiting time. Furthermore, we propose a delayed offloading scheme with balking to enhance quality of experience. The balking scheme is characterized based on 1) current WLAN status; 2) number of packets queued for transmission; and 3) packet deadline. The proposed scheme achieves reduction in mean transmission delay without sacrificing much of the offloading efficiency. The performance of the scheme is mathematically analyzed using matrix-geometric techniques and validated through simulation.
Auteurs: Anusree Ajith;T. G. Venkatesh;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1143 - 1146
Editeur: IEEE
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» QoS-Constrained Relay Control for Full-Duplex Relaying With SWIPT
Résumé:
This study investigates relay control for simultaneous wireless information and power transfer in full-duplex relay networks under Nakagami- $m$ fading channels. Unlike previous work, harvest-transmit (HT) and general harvest-transmit-store (HTS) models are respectively considered to maximize average throughput subject to quality of service (QoS) constraints. The end-to-end outage probability of the network in an HT model is presented in an exact integral-form. To prevent outage performance degradation in an HT model, time switching (TS) is designed to maximize average throughput subject to QoS constraints of minimizing outage probability and maintaining a target outage probability, respectively. The optimal TS factors subject to QoS constraints are presented for an HT model. In general, in an HTS model, energy scheduling is performed across different transmission blocks and TS is performed within each block. Compared with the block-based HTS model without TS, the proposed general HTS model can greatly improve outage performance via greedy search (GS). By modeling the relay’s energy levels as a Markov chain with a two-stage state transition, the outage probability for the GS implementation of the general HTS model is derived. To demonstrate the practical significance of QoS-constrained relay control, numerical results are presented showing that the proposed relay control achieves substantial improvement of outage performance and successful rate.
Auteurs: Hongwu Liu;Kyeong Jin Kim;Kyung Sup Kwak;H. Vincent Poor;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2936 - 2949
Editeur: IEEE
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» QoS-Driven Resource Allocation and EE-Balancing for Multiuser Two-Way Amplify-and-Forward Relay Networks
Résumé:
In this paper, we study the problem of energy-efficient resource allocation in multiuser two-way amplify-and-forward (AF) relay networks with the aim of maximizing the energy efficiency (EE), while ensuring the quality-of-service (QoS) requirements and balancing the EE of the user links. We formulate an EE-balancing optimization problem that maximizes the ratio of the spectral efficiency (SE) over the total power dissipation subject to QoS and a limited transmit power constraints. The problem which maximizes the EE by jointly optimizing the subcarrier pairing, power allocation, and subcarrier allocation, turns out to be a non-convex fractional mixed-integer nonlinear programming problem, which has an intractable complexity in general. We apply a concave lower bound on the achievable sum rate and a series of convex transformations to make the problem convex one and propose an iterative algorithm for iteratively tightening the lower bound and finding the optimal solution through dual decomposition approach. In addition, a low-complexity suboptimal algorithm is investigated. We then characterize the impact of various network parameters on the attainable EE and SE of the network employing both EE maximization and SE maximization algorithms when the network is designed from the EE perspective. Simulation results demonstrate the effectiveness of the proposed algorithms.
Auteurs: Keshav Singh;Ankit Gupta;Tharmalingam Ratnarajah;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3189 - 3204
Editeur: IEEE
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» Quadrature Spatial Modulation for 5G Outdoor Millimeter–Wave Communications: Capacity Analysis
Résumé:
Capacity analysis for millimeter–wave (mmWave) quadrature spatial modulation (QSM) multiple-input multiple-output (MIMO) system is presented in this paper. QSM is a new MIMO technique proposed to enhance the performance of conventional spatial modulation (SM) while retaining almost all its inherent advantages. Furthermore, mmWave utilizes a wide-bandwidth spectrum and is a very promising candidate for future wireless systems. Detailed and novel analysis of the mutual information and the achievable capacity for mmWave–QSM system using a 3-D statistical channel model for outdoor mmWave communications are presented in this paper. Monte Carlo simulation results are provided to corroborate derived formulas. Obtained results reveal that the 3-D mmWave channel model can be closely approximated by a log–normal fading channel. The conditions under which capacity can be achieved are derived and discussed. It is shown that the capacity of QSM system can be achieved, by carefully designing the constellation symbols for each specific channel model.
Auteurs: Abdelhamid Younis;Nagla Abuzgaia;Raed Mesleh;Harald Haas;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2882 - 2890
Editeur: IEEE
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» Quantifying Nonlinear Contributions to Cortical Responses Evoked by Continuous Wrist Manipulation
Résumé:
Cortical responses to continuous stimuli as recorded using either magneto- or electroencephalography (EEG) have shown power at harmonics of the stimulated frequency, indicating nonlinear behavior. Even though the selection of analysis techniques depends on the linearity of the system under study, the importance of nonlinear contributions to cortical responses has not been formally addressed. The goal of this paper is to quantify the nonlinear contributions to the cortical response obtained from continuous sensory stimulation. EEG was used to record the cortical response evoked by continuous movement of the wrist joint of healthy subjects applied with a robotic manipulator. Multisine stimulus signals (i.e., the sum of several sinusoids) elicit a periodic cortical response and allow to assess the nonlinear contributions to the response. Wrist dynamics (relation between joint angle and torque) were successfully linearized, explaining 99% of the response. In contrast, the cortical response revealed a highly nonlinear relation; where most power ( $sim 80$ %) occurred at non-stimulated frequencies. Moreover, only 10% of the response could be explained using a nonparametric linear model. These results indicate that the recorded evoked cortical responses are governed by nonlinearities and that linear methods do not suffice when describing the relation between mechanical stimulus and cortical response.
Auteurs: Martijn P. Vlaar;Teodoro Solis-Escalante;Alistair N. Vardy;Frans C. T. van der Helm;Alfred C. Schouten;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 05.-2017, volume: 25, issue:5, pages: 481 - 491
Editeur: IEEE
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» Quantization Design for Distributed Optimization
Résumé:
We consider the problem of solving a distributed optimization problem using a distributed computing platform, where the communication in the network is limited: each node can only communicate with its neighbors and the channel has a limited data-rate. A common technique to address the latter limitation is to apply quantization to the exchanged information. We propose two distributed optimization algorithms with an iteratively refining quantization design based on the inexact proximal gradient method and its accelerated variant. We show that if the parameters of the quantizers, i.e., the number of bits and the initial quantization intervals, satisfy certain conditions, then the quantization error is bounded by a linearly decreasing function and the convergence of the distributed algorithms is guaranteed. Furthermore, we prove that after imposing the quantization scheme, the distributed algorithms still exhibit a linear convergence rate, and show complexity upper-bounds on the number of iterations to achieve a given accuracy. Finally, we demonstrate the performance of the proposed algorithms and the theoretical findings for solving a distributed optimal control problem.
Auteurs: Ye Pu;Melanie N. Zeilinger;Colin N. Jones;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2107 - 2120
Editeur: IEEE
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» R-VCANet: A New Deep-Learning-Based Hyperspectral Image Classification Method
Résumé:
Deep-learning-based methods have displayed promising performance for hyperspectral image (HSI) classification, due to their capacity of extracting deep features from HSI. However, these methods usually require a large number of training samples. It is quite difficult for deep-learning model to provide representative feature expression for HSI data when the number of samples are limited. In this paper, a novel simplified deep-learning model, rolling guidance filter (RGF) and vertex component analysis network (R-VCANet), is proposed, which achieves higher accuracy when the number of training samples is not abundant. In R-VCANet, the inherent properties of HSI data, spatial information and spectral characteristics, are utilized to construct the network. And by this means the obtained model could generate more powerful feature expression with less samples. First, spectral and spatial information are combined via the RGF, which could explore the contextual structure features and remove small details from HSI. More importantly, we have designed a new network called vertex component analysis network for deep features extraction from the smoothed HSI. Experiments on three popular datasets indicate that the proposed R-VCANet based method reveals better performance than some state-of-the-art methods, especially when the training samples available are not abundant.
Auteurs: Bin Pan;Zhenwei Shi;Xia Xu;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1975 - 1986
Editeur: IEEE
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» Radio Frequency Interference Mitigation in High-Frequency Surface Wave Radar Based on CEMD
Résumé:
Radio frequency interference (RFI) is a common interference source in high-frequency surface wave (HFSW) radar. Its existence degrades the performance of HFSW radar greatly and makes it necessary to find an effective method to mitigate the interferences. There are two kinds of RFI in the experimental data. One is transient RFI, which is usually suppressed by temporal processing. The other is nontransient RFI, which is suppressed by adaptive beamforming methods. However, the temporal processing techniques suffer performance loss in nontransient cases, whereas the adaptive beamforming methods need spatially structuring, which is difficult to meet within the coherent integration time (CIT) of a few minutes. The fact that the experimental data are usually interfered by two kinds of RFI over a CIT motivates us to find a unified method for interference mitigation. In this letter, a new method based on complex empirical mode decomposition (CEMD) is proposed. CEMD is a local decomposition algorithm that can decompose the echoes and the RFI including transient and nontransient RFI into different intrinsic mode functions (IMFs). Then, the IMFs that correspond to RFI are processed. Experimental results indicate that the proposed method can effectively mitigate both kinds of RFI, and improve the signal-to-noise ratio without losing echoes.
Auteurs: Zezong Chen;Fei Xie;Chen Zhao;Chao He;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 764 - 768
Editeur: IEEE
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» Radiotherapy Planning Using an Improved Search Strategy in Particle Swarm Optimization
Résumé:
Objective: Evolutionary stochastic global optimization algorithms are widely used in large-scale, nonconvex problems. However, enhancing the search efficiency and repeatability of these techniques often requires well-customized approaches. This study investigates one such approach. Methods: We use particle swarm optimization (PSO) algorithm to solve a 4D radiation therapy (RT) inverse planning problem, where the key idea is to use respiratory motion as an additional degree of freedom in lung cancer RT. The primary goal is to administer a lethal dose to the tumor target while sparing surrounding healthy tissue. Our optimization iteratively adjusts radiation fluence-weights for all beam apertures across all respiratory phases. We implement three PSO-based approaches: conventionally used unconstrained, hard-constrained, and our proposed virtual search. As proof of concept, five lung cancer patient cases are optimized over ten runs using each PSO approach. For comparison, a dynamically penalized likelihood (DPL) algorithm—a popular RT optimization technique is also implemented and used. Results: The proposed technique significantly improves the robustness to random initialization while requiring fewer iteration cycles to converge across all cases. DPL manages to find the global optimum in 2 out of 5 RT cases over significantly more iterations. Conclusion: The proposed virtual search approach boosts the swarm search efficiency, and consequently, improves the optimization convergence rate and robustness for PSO. Significance: RT planning is a large-scale, nonconvex optimization problem, where finding optimal solutions in a clinically practical time is critical. Our proposed approach can potentially improve the optimization efficiency in similar time-sensitive problems.
Auteurs: Arezoo Modiri;Xuejun Gu;Aaron M. Hagan;Amit Sawant;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 980 - 989
Editeur: IEEE
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» Railway Traffic Conflict Detection via a State Transition Prediction Approach
Résumé:
Conflict detection and resolution is one of the most important tasks in daily railway traffic management, although it is still difficult to solve all its aspects. In fact, the aspect of conflict detection has not been amply studied. In this paper, an approach of traffic state prediction and conflict detection, based on proper state transition maps (STMaps) and corresponding relation matrices, is proposed. First, the traffic state sequences, which mainly concern infrastructure status and train movement information, are studied. These state sequences are expressed as segment and route state vectors and kept in corresponding state-domain tables (SDTables). The empirical state transitions are then applied to detect irregular states in a dynamic traffic environment. Furthermore, the structural constraints of infrastructure topology and route compatibilities are represented in matrices to aid the calculation and prediction of potential conflicting situations. Scenarios such as train delay and infrastructure failure are designed to test the proposed approach. The test results show that irregular states can be efficiently detected and potential conflicts can be further identified, and the detailed conflict information is also approachable.
Auteurs: Taomei Zhu;José Manuel Mera Sánchez de Pedro;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1268 - 1278
Editeur: IEEE
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» Rakeness-Based Design of Low-Complexity Compressed Sensing
Résumé:
Compressed Sensing (CS) can be introduced in the processing chain of a sensor node as a mean to globally reduce its operating cost, while maximizing the quality of the acquired signal. We exploit CS as a simple early-digital compression stage that performs a multiplication of the signal by a matrix. The operating costs (e.g., the consumed power) of such an encoding stage depend on the number of rows of the matrix, but also on the value and position of the rows’ coefficients. Our novel design flow yields optimized sparse matrices with very few rows. It is a non-trivial extension of the rakeness-based approach to CS and yields an extremely lightweight stage implemented by a very small number of possibly signed sums with an excellent compression performance. By means of a general signal model we explore different corners of the design space and show that, for example, our method is capable of compressing the signal by a factor larger than 2.5 while not considering 30% of the original samples (so that they may not be acquired at all, leaving the analog front-end and ADC stages inactive) and by processing each of the considered samples with not more than three signed sums.
Auteurs: Mauro Mangia;Fabio Pareschi;Valerio Cambareri;Riccardo Rovatti;Gianluca Setti;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1201 - 1213
Editeur: IEEE
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» RAMSYS: Resource-Aware Asynchronous Data Transfer with Multicore SYStems
Résumé:
High-speed data transfer is vital to data-intensive computing that often requires moving large data volumes efficiently within a local data center and among geographically dispersed facilities. Effective utilization of the abundant resources in modern multicore environments for data transfer remains a persistent challenge, particularly, for Non-Uniform Memory Access (NUMA) systems wherein the locality of data accessing is an important factor. This requires rethinking how to exploit parallel access to data and to optimize the storage and network I/Os. We address this challenge and present a novel design of asynchronous processing and resource-aware task scheduling in the context of high-throughput data replication. Our software allocates multiple sets of threads to different stages of the processing pipeline, including storage I/O and network communication, based on their capacities. Threads belonging to each stage follow an asynchronous model, and attain high performance via multiple locality-aware and peer-aware mechanisms, such as task grouping, buffer sharing, affinity control and communication protocols. Our design also integrates high performance features to enhance the scalability of data transfer in several scenarios, e.g., file-level sorting, block-level asynchrony, and thread-level pipelining. Our experiments confirm the advantages of our software under different types of workloads and dynamic environments with contention for shared resources, including a 28-160 percent increase in bandwidth for transferring large files, 1.7-66 times speed-up for small files, and up to 108 percent larger throughput for mixed workloads compared with three state of the art alternatives, GridFTP , BBCP and Aspera.
Auteurs: Tan Li;Yufei Ren;Dantong Yu;Shudong Jin;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1430 - 1444
Editeur: IEEE
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» Rapid Detection of pM Concentration of Insulin Using Microwave Whispering Gallery Mode
Résumé:
In this paper, we are going to investigate insulin, a bio-molecule responsible for the onset of diabetes, which is generally diagnosed using the conventional ELISA method. Its picomolar concentration in blood and short life time was a challenge in developing a sensor sensitive to such small volumes. This paper presents an experimental study of the dielectric properties of hepes buffer solution with varying concentration of insulin, a peptide hormone at microwave frequency range. A composite whispering gallery electric mode ( $WGE_{800}$ ) microwave dielectric resonator with sapphire and polycarbonate disposable sample holding disc has been used at 17.59 GHz. From observations, imaginary part of permittivity has been found very sensitive to changes in insulin concentration ranging from $2.0327times 10^{-8} % $ to $21.9995times 10^{-8} % $ . Studies show that the present method has the potential to detect and sense ultralow concentration of bioanalyte with regression coefficient 0.943 and sensitivity of 0.039 for 10 pM change in insulin concentration.
Auteurs: Ritika Verma;K. S. Daya;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2758 - 2765
Editeur: IEEE
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» Rapid Nondestructive-Testing Technique for In-Line Quality Control of Li-Ion Batteries
Résumé:
Quality control in the production of automotive Li-ion cells is essential for both safety and economic reasons. At present, as part of the production process, it is common practice to store Li-ion cells for up to two weeks to analyze self-discharge performance and to subject sample cells to months of cycling to assess lifetime performance. This paper presents a new state-of-the-art nondestructive testing technique for automotive scale, Li-ion batteries. Importantly, the test can discriminate between viable and nonviable cells in less than one minute. This is significantly quicker than many industrially applied techniques. The proposed method, developed in partnership with three independent original equipment manufacturer automotive Li-ion cell manufacturers, uses empirical data gathered off-line for benchmarking cell response followed by a unique targeting process to reduce the test time to a level compatible with industrial manufacturing processes. The technique used is a targeted form of electrochemical impedance spectroscopy (EIS) using a commercially available potentiostat with EIS capability. The novel aspect of the research is the treatment of off-line empirical data, the construction of an empirical library database, and the development of a reliable and robust in-line test procedure. For reasons of commercial sensitivity, no knowledge of the underlying chemistry of the cells is available for use. This demonstrates the functionality of the proposed method across a range of different cell technologies and its applicability to multiple battery technologies.
Auteurs: Simon M. Lambert;Matthew Armstrong;Pierrot S. Attidekou;Paul A. Christensen;James D. Widmer;Chen Wang;Keith Scott;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4017 - 4026
Editeur: IEEE
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» Ray Tracing and Modal Methods for Modeling Radio Propagation in Tunnels With Rough Walls
Résumé:
At the ultrahigh frequencies common to portable radios, tunnels such as mine entries are often modeled by hollow dielectric waveguides. The roughness condition of the tunnel walls has an influence on radio propagation, and therefore should be taken into account when an accurate power prediction is needed. This paper investigates how wall roughness affects radio propagation in tunnels, and presents a unified ray tracing and modal method for modeling radio propagation in tunnels with rough walls. First, general analytical formulas for modeling the influence of the wall roughness are derived, based on the modal method and the ray tracing method, respectively. Second, the equivalence of the ray tracing and modal methods in the presence of wall roughnesses is mathematically proved, by showing that the ray tracing-based analytical formula can converge to the modal-based formula through the Poisson summation formula. The derivation and findings are verified by simulation results based on ray tracing and modal methods.
Auteurs: Chenming Zhou;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2624 - 2634
Editeur: IEEE
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» Ray-Tracing-Assisted Fingerprinting Based on Channel Impulse Response Measurement for Indoor Positioning
Résumé:
Position fingerprinting (FP), in which a common position signature is based on the received signal strength (RSS), is one of the most efficient indoor positioning methods. Another position signature, known as the channel impulse response (CIR), is regarded as a linear temporal filter, which characterizes the multipath channel of the operating environment. We implement a channel sounder based on an orthogonal frequency-division multiplexing system to collect off-line/online CIR measurements and develop a ray-tracing (RT) channel predictor to capture the main characteristics of the channel for the off-line predicted database. We are the first to utilize RT as a channel predictor to assist indoor FP using CIR measurements. We utilize coarse localization to classify the reference points (RPs) based on the access point with the strongest RSS. We propose an RT-assisted FP (RAFP) method, in which we estimate a position by fusing the measured and predicted signatures to find the RPs with the highest correlation values between the online measurement and the off-line measured and simulated CIR databases. Experimental results show that the RAFP—positioning with a hybrid of the predicted and measured CIR—reduces the FP localization error by 25%. By incorporating simulated CIRs, the RAFP has the advantages in reducing human labor for off-line measurement collection and in using less number of CIR measurements to maintain a satisfactory performance. The results encourage a further development to reduce the cost by replacing the sounding system with the wireless network interface cards for a scalable deployment.
Auteurs: Po-Hsuan Tseng;Yao-Chia Chan;Yi-Jie Lin;Ding-Bing Lin;Nan Wu;Tsai-Mao Wang;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 1032 - 1045
Editeur: IEEE
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» Reagent Addition Control for Stibium Rougher Flotation Based on Sensitive Froth Image Features
Résumé:
The reagent addition control level of stibium rougher flotation has a significant impact on the performance of cleaner and scavenger flotation. Currently, due to the complexity of the froth flotation process, the addition rates of reagents, which are controlled by operators, are often not regulated properly in time. Therefore, it is necessary to study a control strategy for the reagent addition rates. This paper proposes a sensitive froth image feature (FIF)-based control strategy that involves an estimator of the feed grade, a preset controller, and a feedback controller. Because the addition rates of reagents should be regulated according to the feed grade, an estimator model for feed grade is built based on the probabilistic support vector regress method. Then, the addition rates of reagents are preset according to the feed grade type based on the operational pattern method. To overcome the steady-state disturbances, a feedback dosage controller is developed to further regulate the reagent addition rates based on the interval type-II fuzzy control system. In the proposed control strategy, the selection of FIF, the inference of feed grade, and the process of uncertainty in sample data are described in detail. Finally, industrial experiments show the effectiveness of the proposed method.
Auteurs: Yongfang Xie;Jia Wu;Degang Xu;Chunhua Yang;Weihua Gui;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4199 - 4206
Editeur: IEEE
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» Real-Time Classification of Healthy and Apnea Subjects Using ECG Signals With Variational Mode Decomposition
Résumé:
This paper introduces a novel method for the classification of healthy and apnea subjects using variational mode decomposition. The proposed method distinguishes the apnea and normal subjects with the help of an electrocardiogram (ECG) signal. Polysomnogram is the gold standard used for the identification of apnea subjects. This process is complex, expensive, and time-consuming. In this paper, both online and off-line-based feature extraction and classification methods are explored. The proper extraction of suitable features from the signal is done by applying variational mode decomposition. Two features are extracted from the variational mode functions, namely, energy and RR interval of ECG signal. These features are fed in to a support vector machine classifier, where they are classified as healthy and apnea. The accuracy obtained for both online and off-line processes are 97.5% and 95%, respectively.
Auteurs: A. Smruthy;M. Suchetha;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3092 - 3099
Editeur: IEEE
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» Real-Time Optimization of Automatic Control Systems With Application to BLDC Motor Test Rig
Résumé:
Driven by the increasing demands on production quality, system performance, and the reliability and safety issues of process industry, this paper proposes an integrated process monitoring and control design technique for industrial control systems. The proposed approach is an alternative realization of Youla parameterization which allows the performance of the controlled systems to be improved without modifying or replacing the predesigned control systems, while the closed-loop stability is guaranteed. In addition, a residual signal is available for the fault detection and isolation purpose. The effectiveness and performance of the proposed approach are demonstrated on a brushless direct current motor test rig.
Auteurs: Hao Luo;Minjia Krueger;Tim Koenings;Steven X. Ding;Shane Dominic;Xu Yang;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4306 - 4314
Editeur: IEEE
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» Real-Time Traffic Light Recognition Based on Smartphone Platforms
Résumé:
Traffic light recognition is of great significance for driver assistance or autonomous driving. In this paper, a traffic light recognition system based on smartphone platforms is proposed. First, an ellipsoid geometry threshold model in Hue Saturation Lightness color space is built to extract interesting color regions. These regions are further screened with a postprocessing step to obtain candidate regions that satisfy both color and brightness conditions. Second, a new kernel function is proposed to effectively combine two heterogeneous features, histograms of oriented gradients and local binary pattern, which is used to describe the candidate regions of traffic light. A kernel extreme learning machine (K-ELM) is designed to validate these candidate regions and simultaneously recognize the phase and type of traffic lights. Furthermore, a spatial-temporal analysis framework based on a finite-state machine is introduced to enhance the reliability of the recognition of the phase and type of traffic light. Finally, a prototype of the proposed system is implemented on a Samsung Note 3 smartphone. To achieve a real-time computational performance of the proposed K-ELM, a CPU-GPU fusion-based approach is adopted to accelerate the execution. The experimental results on different road environments show that the proposed system can recognize traffic lights accurately and rapidly.
Auteurs: Wei Liu;Shuang Li;Jin Lv;Bing Yu;Ting Zhou;Huai Yuan;Hong Zhao;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 05.-2017, volume: 27, issue:5, pages: 1118 - 1131
Editeur: IEEE
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» Real-Time Two-Dimensional Imaging of Solid Contaminants in Gas Pipelines Using an Electrical Capacitance Tomography System
Résumé:
In this paper, an electrical capacitance tomography (ECT) system for real-time measurement of solid contaminants in gas pipelines is presented. It consists of a ring of eight electrodes evenly distributed in the circular cross section of the probe. The speed-up enhancement is achieved using a field programmable gate array (FPGA) for the post-processing part of the system to accelerate the intensive matrix multiplications which are required in the image reconstruction algorithm. Experimental results on field-collected solid contaminants demonstrated the capability of the system to build in real-time two-dimensional cross-sectional images of the contaminants while giving an estimated measurement of their concentration. This allows the flow regime of the contaminants in the pipeline to be identified. Results also show that using Altera's Stratix V FPGA, 305 KLEs are required to achieve image reconstruction throughput up to 3233 frames/s for image size of 64 × 64 pixels. Simulation results were also conducted using finite-element method solver to assess the ECT probe for various image reconstruction algorithms (i.e., Linear back projection, Landweber, and modified Landweber algorithms). The results indicate a good matching with the experimental results.
Auteurs: Mahmoud Meribout;Imran M. Saied;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3989 - 3996
Editeur: IEEE
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» Recent Advances in the Capture and Display of Macroscopic and Microscopic 3-D Scenes by Integral Imaging
Résumé:
The capture and display of images of 3-D scenes under incoherent and polychromatic illumination is currently a hot topic of research, due to its broad applications in bioimaging, industrial procedures, military and surveillance, and even in the entertainment industry. In this context, Integral Imaging (InI) is a very competitive technology due to its capacity for recording with a single exposure the spatial-angular information of light-rays emitted by the 3-D scene. From this information, it is possible to calculate and display a collection of horizontal and vertical perspectives with high depth of field. It is also possible to calculate the irradiance of the original scene at different depths, even when these planes are partially occluded or even immersed in a scattering medium. In this paper, we describe the fundaments of InI and the main contributions to its development. We also focus our attention on the recent advances of the InI technique. Specifically, the application of InI concept to microscopy is analyzed and the achievements in resolution and depth of field are explained. In a different context, we also present the recent advances in the capture of large scenes. The progresses in the algorithms for the calculation of displayable 3-D images and in the implementation of setups for the 3-D displays are reviewed.
Auteurs: Manuel Martínez-Corral;Adrián Dorado;Juan Carlos Barreiro;Genaro Saavedra;Bahram Javidi;
Apparue dans: Proceedings of the IEEE
Date publication: 05.-2017, volume: 105, issue:5, pages: 825 - 836
Editeur: IEEE
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» Reciprocity Calibration for Massive MIMO: Proposal, Modeling, and Validation
Résumé:
This paper presents a mutual coupling-based calibration method for time-division-duplex massive MIMO systems, which enables downlink precoding based on uplink channel estimates. The entire calibration procedure is carried out solely at the base station (BS) side by sounding all BS antenna pairs. An expectation-maximization (EM) algorithm is derived, which processes the measured channels in order to estimate calibration coefficients. The EM algorithm outperforms the current state-of-the-art narrow-band calibration schemes in a mean squared error and sum-rate capacity sense. Like its predecessors, the EM algorithm is general in the sense that it is not only suitable to calibrate a co-located massive MIMO BS, but also very suitable for calibrating multiple BSs in distributed MIMO systems. The proposed method is validated with experimental evidence obtained from a massive MIMO testbed. In addition, we address the estimated narrow-band calibration coefficients as a stochastic process across frequency, and study the subspace of this process based on measurement data. With the insights of this study, we propose an estimator which exploits the structure of the process in order to reduce the calibration error across frequency. A model for the calibration error is also proposed based on the asymptotic properties of the estimator, and is validated with measurement results.
Auteurs: Joao Vieira;Fredrik Rusek;Ove Edfors;Steffen Malkowsky;Liang Liu;Fredrik Tufvesson;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3042 - 3056
Editeur: IEEE
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» Recognition - A Critical Responsibility [President's Message]
Résumé:
Presents the President’s message for this issue of the publication.
Auteurs: Tomy Sebastian;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 05.-2017, volume: 23, issue:3, pages: 4 - 72
Editeur: IEEE
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» Recognizing and Presenting the Storytelling Video Structure With Deep Multimodal Networks
Résumé:
In this paper, we propose a novel scene detection algorithm which employs semantic, visual, textual, and audio cues. We also show how the hierarchical decomposition of the storytelling video structure can improve retrieval results presentation with semantically and aesthetically effective thumbnails. Our method is built upon two advancements of the state of the art: first is semantic feature extraction which builds video-specific concept detectors; and second is multimodal feature embedding learning that maps the feature vector of a shot to a space in which the Euclidean distance has task specific semantic properties. The proposed method is able to decompose the video in annotated temporal segments which allow us for a query specific thumbnail extraction. Extensive experiments are performed on different data sets to demonstrate the effectiveness of our algorithm. An in-depth discussion on how to deal with the subjectivity of the task is conducted and a strategy to overcome the problem is suggested.
Auteurs: Lorenzo Baraldi;Costantino Grana;Rita Cucchiara;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 05.-2017, volume: 19, issue:5, pages: 955 - 968
Editeur: IEEE
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» Recognizing the Gradual Changes in sEMG Characteristics Based on Incremental Learning of Wavelet Neural Network Ensemble
Résumé:
Most myoelectric prosthetic hands use a fixed pattern recognition model to identify the user's hand motion commands. Since surface electromyogram (sEMG) characteristics vary with time, it is difficult to employ the fixed pattern recognition model in identifying hand motion commands stably for a long period of time. In order to adapt to the gradual changes in sEMG characteristics, we utilized incremental learning based on the wavelet neural network (WNN) ensemble, and used negative correlation learning (NCL) to train it. To verify the effect of the proposed method, a group of subjects executed six hand motions in a continual experiment for more than 2 h. Compared with the fixed pattern recognition model, the classification accuracy rate of incremental learning with nonintegration becomes substantially improved. In addition, the results of the WNN ensemble with the fixed-size mode are more stable than those of the WNN ensemble with the growth mode. The experimental results demonstrate that our method can recognize the gradual changes in sEMG characteristics stably. Using the proposed method, the average accuracy rate is found to be 92.17%, even after a long period of time. Moreover, since the update time is short, the proposed method can be successfully applied in myoelectric prosthetic hands.
Auteurs: Feng Duan;Lili Dai;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4276 - 4286
Editeur: IEEE
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» Reconfiguring the Frequency and Directive Behavior of a Printed V–Shaped Structure
Résumé:
In this communication, a frequency and pattern reconfigurable V–shaped printed antenna is presented. The proposed structure operates at two different frequency bands. The variation in the frequency of operation is achieved by individually extending the length of each of the two antenna arms. The directional behavior of the proposed antenna structure is improved through the incorporation of a triangular parasitic element within the empty space between the two antenna arms. More specifically, the antenna is able to steer its gain pattern to either the left or right directions based on which arm of the V–shaped printed structure is fed. A prototype structure is fabricated and tested to validate the proposed approach in achieving directional behavior over two distinct frequency bands.
Auteurs: Y. Tawk;J. Costantine;C. G. Christodoulou;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2655 - 2660
Editeur: IEEE
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» Reconstruction Guarantee Analysis of Basis Pursuit for Binary Measurement Matrices in Compressed Sensing
Résumé:
Recently, binary 0-1 measurement matrices, especially those from coding theory, were introduced to compressed sensing. Dimakis et al. found that the linear programming (LP) decoding of LDPC codes is very similar to the LP reconstruction of compressed sensing, and they further showed that the sparse binary parity-check matrices of good LDPC codes can be used as provably good measurement matrices for compressed sensing under basis pursuit (BP). Moreover, Khajehnejad et al. made use of girth to certify the good performances of sparse binary measurement matrices. In this paper, we examine the performance of binary measurement matrices with uniform column weight and arbitrary girth under BP. For a fixed measurement matrix, we first introduce a performance indicator $w^{BP}_{min}$ called minimum BP weight, and show that any $k$ -sparse signals could be exactly recovered by BP if and only if $kle (w^{BP}_{min}-1)/2$ . Then, lower bounds of $w^{BP}_{min}$ are studied. Borrowing ideas from the tree bound for the LDPC codes, we obtain several explicit lower bounds of $w_{BP}^{min}$ , which improve on the previous results in some cases. These lower bounds also imply explicit $ell _{1}/ell _{1}$ , $ell _{2}/ell _{1}$ and $ell _infty /ell _{1}$ sparse approximation guarantees, and fur- her confirm that large girth has positive impacts on the performance of binary measurement matrices under BP.
Auteurs: Xin-Ji Liu;Shu-Tao Xia;Fang-Wei Fu;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2922 - 2932
Editeur: IEEE
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» Reconstruction of Subsurface Velocities From Satellite Observations Using Iterative Self-Organizing Maps
Résumé:
A new method based on modified self-organizing maps is presented for the reconstruction of deep ocean current velocities from surface information provided by satellites. This method takes advantage of local correlations in the data-space to improve the accuracy of the reconstructed deep velocities. No assumptions regarding the structure of the water column, nor the underlying dynamics of the flow field, are made. Using satellite observations of surface velocity, sea-surface height and sea-surface temperature, as well as observations of the deep current velocity from autonomous Argo floats to train the map, we are able to reconstruct realistic high-resolution velocity fields at a depth of 1000 m. Validation reveals promising results, with a speed root mean squared error of ~2.8 cm. $text{s}^{-1}$ , more than a factor of two smaller than competing methods, and direction errors consistently smaller than 30°. Finally, we discuss the merits and shortcomings of this methodology.
Auteurs: Christopher Chapman;Anastase Alexandre Charantonis;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 617 - 620
Editeur: IEEE
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» Recover Corrupted Data in Sensor Networks: A Matrix Completion Solution
Résumé:
Affected by hardware and wireless conditions in WSNs, raw sensory data usually have notable data loss and corruption. Existing studies mainly consider the interpolation of random missing data in the absence of the data corruption. There is also no strategy to handle the successive missing data. To address these problems, this paper proposes a novel approach based on matrix completion (MC) to recover the successive missing and corrupted data. By analyzing a large set of weather data collected from 196 sensors in Zhu Zhou, China, we verify that weather data have the features of low-rank, temporal stability, and spatial correlation. Moreover, from simulations on the real weather data, we also discover that successive data corruption not only seriously affects the accuracy of missing and corrupted data recovery but even pollutes the normal data when applying the matrix completion in a traditional way. Motivated by these observations, we propose a novel Principal Component Analysis (PCA)-based scheme to efficiently identify the existence of data corruption. We further propose a two-phase MC-based data recovery scheme, named MC-Two-Phase, which applies the matrix completion technique to fully exploit the inherent features of environmental data to recover the data matrix due to either data missing or corruption. Finally, the extensive simulations with real-world sensory data demonstrate that the proposed MC-Two-Phase approach can achieve very high recovery accuracy in the presence of successively missing and corrupted data.
Auteurs: Kun Xie;Xueping Ning;Xin Wang;Dongliang Xie;Jiannong Cao;Gaogang Xie;Jigang Wen;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1434 - 1448
Editeur: IEEE
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» Reducing the Computational Complexity of Multicasting in Large-Scale Antenna Systems
Résumé:
In this paper, we study the physical layer multicasting to multiple co-channel groups in large-scale antenna systems. The users within each group are interested in a common message and different groups have distinct messages. In particular, we aim at designing the precoding vectors solving the so-called quality of service (QoS) and weighted max-min fairness (MMF) problems, assuming that the channel state information is available at the base station (BS). To solve both problems, the baseline approach exploits the semidefinite relaxation (SDR) technique. Considering a BS with $N$ antennas, the SDR complexity is more than $mathcal {O}(N^{6})$ , which prevents its application in large-scale antenna systems. To overcome this issue, we present two new classes of algorithms that, not only have significantly lower computational complexity than existing solutions, but also largely outperform the SDR-based methods. Moreover, we present a novel duality between transformed versions of the QoS and the weighted MMF problems. The duality explicitly determines the solution to the weighted MMF problem given the solution to the QoS problem, and vice versa. Numerical results are used to validate the effectiveness of the proposed solutions and to make comparisons with existing alternatives under different operating conditions.
Auteurs: Meysam Sadeghi;Luca Sanguinetti;Romain Couillet;Chau Yuen;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 2963 - 2975
Editeur: IEEE
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» Reflections on a Perfect Match: Volunteers and Mentors
Résumé:
Discusses the need for MMTS society volunteers and mentors.
Auteurs: Wayne Shiroma;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 88 - 94
Editeur: IEEE
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» Refractive Index Modulation by Crystallization in Sapphire-Derived Fiber
Résumé:
We have proposed and demonstrated a new refractive index (RI) modulation method based on crystallization in sapphire-derived fibers (SDFs), which are special fibers with a high concentration of alumina in the silica fiber core. Reheating and cooling an SDF with an arc discharge can generate mullite particles in the fiber core. Such crystallization can achieve a maximum RI modulation of ~0.015. Using the point-by-point arc discharge method, crystallization-based long-period gratings (LPGs) can be inscribed in the core of the SDF. Due to the highly modulated RI at the inscribed points, only three to four arc discharge points are required to achieve a strong resonant dip of up to 16 dB in the transmission spectrum of the SDF. The obtained results show that RI modulation by crystallization in SDFs has great potential for the fabrication of functional fiber components that can be applied in high-temperature and -pressure environments.
Auteurs: Lin Hong;Fufei Pang;Huanhuan Liu;Jin Xu;Zhenyi Chen;Ziwen Zhao;Tingyun Wang;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 723 - 726
Editeur: IEEE
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» Regularized Dual Averaging Image Reconstruction for Full-Wave Ultrasound Computed Tomography
Résumé:
Ultrasound computed tomography (USCT) holds great promise for breast cancer screening. Waveform inversion-based image reconstruction methods account for higher order diffraction effects and can produce high-resolution USCT images, but are computationally demanding. Recently, a source encoding technique has been combined with stochastic gradient descent (SGD) to greatly reduce image reconstruction times. However, this method bundles the stochastic data fidelity term with the deterministic regularization term. This limitation can be overcome by replacing SGD with a structured optimization method, such as the regularized dual averaging method, that exploits knowledge of the composition of the cost function. In this paper, the dual averaging method is combined with source encoding techniques to improve the effectiveness of regularization while maintaining the reduced reconstruction times afforded by source encoding. It is demonstrated that each iteration can be decomposed into a gradient descent step based on the data fidelity term and a proximal update step corresponding to the regularization term. Furthermore, the regularization term is never explicitly differentiated, allowing nonsmooth regularization penalties to be naturally incorporated. The wave equation is solved by the use of a time-domain method. The effectiveness of this approach is demonstrated through computer simulation and experimental studies. The results suggest that the dual averaging method can produce images with less noise and comparable resolution to those obtained by the use of SGD.
Auteurs: Thomas P. Matthews;Kun Wang;Cuiping Li;Neb Duric;Mark A. Anastasio;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 811 - 825
Editeur: IEEE
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» Relationship Between Mirrored Aperture Synthesis Radiometers and Aperture Synthesis Radiometers
Résumé:
The mirrored aperture synthesis radiometer (MASR) has been proposed as a new technique for high-resolution observation. Compared with ASRs, MASRs have the advantage of lower system complexity. However, the relationship between MASRs and ASRs has not been studied. In order to thoroughly study MASRs, it is necessary to establish the relationship between MASRs and ASRs. In this letter, the array factor of 1-D MASRs in the discrete cosine transform domain (DCT-domain) is defined. The reconstructed image for a 1-D MASR is a symmetric convolution of the observed brightness temperature distribution and the defined array factor in the DCT domain. Since a symmetric convolution can be turned into a linear convolution, the relationship between 1-D MASRs and 1-D ASRs can be established. A 1-D MASR is equivalent to a 1-D ASR that has a mirrored window. Additionally, for the equivalent 1-D ASR, its observed scene is a symmetrically extended real scene. This established relationship is validated by the simulation results. In practical applications, a MASR can be understood as an ASR.
Auteurs: Yufang Li;Qingxia Li;Li Feng;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 631 - 635
Editeur: IEEE
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» Relationships Between Subclasses of Integral Input-to-State Stability
Résumé:
A certain “qualitative equivalence” has been recently demonstrated between integral input-to-state stability (iISS) and a nonlinear $mathcal{L}_2$ -gain property. Furthermore, it has been observed that the properties of strong iISS and nonlinear $mathcal{L}_2$-gain are preserved when multiple systems satisfying the respective property are connected in cascade. This technical note clarifies the relationships between various input-to-state stability and (non)linear $mathcal{L}_p$ -gain properties.
Auteurs: Christopher M. Kellett;Peter M. Dower;Hiroshi Ito;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2476 - 2482
Editeur: IEEE
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» Reliability Analysis of LPCVD SiN Gate Dielectric for AlGaN/GaN MIS-HEMTs
Résumé:
In this paper, we investigate Low Pressure Chemical Vapor Deposition (LPCVD) SiN as a gate isolation material for AlGaN/gallium nitride (GaN) MIS-high electron mobility transistor power transistors. We compared the dielectric failure by forward-biased constant-current stress time-dependent dielectric breakdown measurements and statistical Weibull analysis. Several 4” AlGaN/GaN-on-Si wafers have been processed with different gate isolations and processes. Our investigation includes the dependence of the dielectric breakdown on the process flow (influence of dry etch), the thickness of the dielectric (12–20 nm), the area scaling, and the gate electrode, where we also consider the recently presented poly-silicon electrode. Additionally, we show the influence of the current density through the gate on the charge-to-breakdown characteristics as well as the influence of the temperature on the breakdown behavior. Using the poly-silicon electrode and 20 nm LPCVD SiN as gate isolation, we achieved a charge-to-breakdown of ${Q}_{text {BD, 10}~text {mA}/text {cm}^{2}} ={3.7} ~ text {kC}/text {cm}^{{2}}$ at $text {T} = {130} {^{circ }}text {C}$ for ${j} = {10} ~ text {mA}/text {cm}^{{2}}$ . A 20-years lifetime (100 ppm, $text {T} = {130} {^{circ }}text {C}$ ) extrapolation for a scaled area of ${0.2} ~ text {mm}^{{2}}$ ( $buildrel wedge over = {W}_{G} = {100} ~ text {mm}$ ) leads to a positive gate voltage of ${V}_{text {G}} = {9.4} ~ text {V}$ .
Auteurs: Simon A. Jauss;Kazim Hallaceli;Sebastian Mansfeld;Stephan Schwaiger;Walter Daves;Oliver Ambacher;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2298 - 2305
Editeur: IEEE
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» Reliability Assessment of InAlN/GaN HFETs With Lifetime $8.9times 10^{mathrm {6}}$ h
Résumé:
Based on the three-temperature 30 V DC stress tests, the reliability of InAlN/GaN heterostructure field-effect transistors (HFETs) on SiC substrate was assessed for the first time. Using a failure criterion defined as 20% reduction in zero-gate-voltage drain current ( $I_{mathrm {dss}}$ ), the activation energy was estimated to be 1.94 eV, and the median time to failure was estimated to be $8.9times 10^{6}$ h at junction temperature of 150°. Moreover, the high temperature material storage indicates that the lifetime of InAlN/GaN HFETs can be further prolonged by the optimization of device process, such as introducing LPCVD SiN or ALD Al2O3 as gate dielectric layer.
Auteurs: Yuangang Wang;Yuanjie Lv;Xubo Song;Lei Chi;Jiayun Yin;Xingye Zhou;Yulong Fang;Xin Tan;Hongyu Guo;Hao Peng;Guodong Gu;Zhihong Feng;Shujun Cai;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 604 - 606
Editeur: IEEE
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» Reliability of Universal Decoding Based on Vector-Quantized Codewords
Résumé:
Motivated by applications of biometric identification and content identification systems, we consider the problem of random coding for channels, where each codeword undergoes vector quantization, and where the decoder bases its decision only on the compressed codewords and the channel output, which is, in turn, the channel’s response to the transmission of an original codeword, before compression. For memoryless sources and memoryless channels with finite alphabets, we propose a new universal decoder and analyze its error exponent, which improves on an earlier result by Dasarathy and Draper (2011), who used the classic maximum mutual information universal decoder. We show that our universal decoder provides the same error exponent as that of the optimal, maximum likelihood decoder, at least as long as all single-letter transition probabilities of the channel are positive.
Auteurs: Neri Merhav;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2696 - 2709
Editeur: IEEE
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» Removal of ICI and IBI in Wireless Heterogeneous Networks With Timing Misalignment
Résumé:
Since a small cell base station (SBS) of an orthogonal frequency division multiple access heterogeneous network (HetNet) does not intend to align arriving macrocell user signals, inter-carrier interference (ICI) and inter-block interference (IBI) inevitably arise in the uplink demodulation at the SBS. This letter proposes a novel precoding scheme based on interference alignment to remove the uplink ICI and IBI in a HetNet completely. The proposed scheme is able to remove the ceiling effect on the small cell uplink rate and increase the degrees of freedom of the system. Simulation results demonstrate the superiority of the scheme.
Auteurs: Hong Wang;Rongfang Song;Shu-Hung Leung;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1195 - 1198
Editeur: IEEE
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» Removal of Optically Thick Clouds From High-Resolution Satellite Imagery Using Dictionary Group Learning and Interdictionary Nonlocal Joint Sparse Coding
Résumé:
In this paper, we propose a method for cloud removal in a cloud-contaminated high-resolution (HR) optical satellite image with two kinds of auxiliary images of different types: a low-resolution (LR) optical satellite composite image and a synthetic aperture radar (SAR) image. In the proposed method, we assume that cloud-contaminated and cloud-free regions have been detected accurately, then dictionary group learning (DGL) is used to establish structure correspondences between HR, LR, and SAR data from cloud-free patches, while interdictionary nonlocal joint sparse coding (INJSC) is used to estimate the universal representation coefficients of patches contaminated by clouds, and finally, cloud-contaminated HR patches can be reconstructed with their universal coefficients and the HR dictionary learned from DGL process. In this way, the missing information in the cloud-contaminated HR image can be reconstructed patch by patch. The proposed method is tested on a series of experiments on both simulated and real data. Experimental results show that both DGL and INJSC are beneficial to better reconstructing the missing information. This method is also compared against our previous work on the same topic, which adopted dictionary pair learning (DPL) and sparse coding (SC) to recover the missing information and achieved state-of-the-art performance at that time. The comparison shows that the method proposed in this paper significantly outperforms the previous one.
Auteurs: Ying Li;Wenbo Li;Chunhua Shen;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1870 - 1882
Editeur: IEEE
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» Renewable Energy Pricing Driven Scheduling in Distributed Smart Community Systems
Résumé:
A smart community is a distributed system consisting of a set of smart homes which utilize the smart home scheduling techniques to enable customers to automatically schedule their energy loads targeting various purposes such as electricity bill reduction. Smart home scheduling is usually implemented in a decentralized fashion inside a smart community, where customers compete for the community level renewable energy due to their relatively low prices. Typically there exists an aggregator as a community wide electricity policy maker aiming to minimize the total electricity bill among all customers. This paper develops a new renewable energy aware pricing scheme to achieve this target. We establish the proof that under certain assumptions the optimal solution of decentralized smart home scheduling is equivalent to that of the centralized technique, reaching the theoretical lower bound of the community wide total electricity bill. In addition, an advanced cross entropy optimization technique is proposed to compute the pricing scheme of renewable energy, which is then integrated in smart home scheduling. The simulation results demonstrate that our pricing scheme facilitates the reduction of both the community wide electricity bill and individual electricity bills compared to the uniform pricing. In particular, the community wide electricity bill can be reduced to only 0.06 percent above the theoretic lower bound.
Auteurs: Yang Liu;Shiyan Hu;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1445 - 1456
Editeur: IEEE
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» Repetitive ${ {X}}$ -Band Relativistic Traveling Wave Oscillator
Résumé:
This paper presents the results of an experimental study of a relativistic traveling wave oscillator with a tubular electron beam of enlarged cross section. Repetitively pulsed (30 Hz) generation of 10.1-GHz, 80-ns microwave pulses in 1-s batches is realized. The microwave pulse power a level of quasi-steady-state oscillation was 220 ± 44 MW. The driving electron beam (370-keV, 2.4-kA, 107-ns pulsewidth) was transported along the interaction space by a quasi-constant (few seconds in duration) external magnetic field with an induction of 0.6 T. The power efficiency of the generator is 25% ± 5%. The energy in a single microwave pulse is about 15 J as measured with an aperture calorimeter.
Auteurs: Eugene M. Totmeninov;Pavel V. Vykhodtsev;Alexei S. Stepchenko;Aleksei I. Klimov;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2398 - 2402
Editeur: IEEE
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» Replacing the Grid Interface Transformer in Wind Energy Conversion System With Solid-State Transformer
Résumé:
In wind energy conversion systems, the fundamental frequency step-up transformer acts as a key interface between the wind turbine and the grid. Recently, there have been efforts to replace this transformer by an advanced power-electronics-based solid-state transformer (SST). This paper proposes a configuration that combines the doubly fed induction generator-based wind turbine and SST operation. The main objective of the proposed configuration is to interface the turbine with the grid while providing enhanced operation and performance. In this paper, SST controls the active power to/from the rotor side converter, thus, eliminating the grid side converter. The proposed system meets the recent grid code requirements of wind turbine operation under fault conditions. Additionally, it has the ability to supply reactive power to the grid when the wind generation is not up to its rated value. A detailed simulation study is conducted to validate the performance of the proposed configuration.
Auteurs: Imran Syed;Vinod Khadkikar;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2152 - 2160
Editeur: IEEE
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» Research on the Cooperative Train Control Strategy to Reduce Energy Consumption
Résumé:
Based on the mature energy-saving strategy of a single train, the optimization of multiple trains' trajectories is studied. A cooperative control model is formulated with the utilization of the regenerative energy considered, which is used to calculate the total energy consumption of an electric subway system under various energy-saving control strategies. Taking the cooperative operation of two trains within the same section of an electrical system as an example, the front one adopt the optimal driving strategy with four modes of movement, which are the maximum traction, cruising, coasting, and the maximum braking by sequence. The latter is controlled by the strategy with four movement modes (mentioned earlier) and five movement modes (namely, the maximum traction, cruising/coasting, the maximum traction, coasting, and the maximum braking), respectively. The minimum energy consumption under different departure headway is calculated by using a heuristic algorithm. It turned out that the optimal energy-saving control strategy can be obtained with the departure headway given, and an energy-saving control strategy corresponding to the minimum energy consumption can be worked out too. The proposed energy-saving strategy can reduce energy consumption by 19.2% at the most.
Auteurs: Jianqiang Liu;Huailong Guo;Yingxue Yu;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1134 - 1142
Editeur: IEEE
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» Research on the Impact of DFIG Virtual Inertia Control on Power System Small-Signal Stability Considering the Phase-Locked Loop
Résumé:
Doubly fed induction generator (DFIG) wind turbines with virtual inertia control are coupled to power system in dynamic characteristics, and the control input of virtual inertia control is directly affected by the tracking ability of phase-locked loop (PLL). Thus, it is urgent to study the impact of DFIG wind turbines with virtual inertia control on power system small-signal stability considering the effects of PLL. First, based on DFIG operation characteristic and control strategy, a small-signal model of interconnected system with DFIG integration considering PLL and virtual inertial control is established. Second, the attenuation time constants of DFIG state variables are calculated, and according to the attenuation speeds of different state variables and the coupling between them, it is found out that PLL and virtual inertia are the main factors that affect the coupling between DFIG and synchronous generators. And then, considering that both PLL and virtual inertia control will affect the oscillation modes of synchronous generators, analytical method is used to reveal system small-signal stability under the joint effects of the two factors quantitatively. Analysis results show that, for DFIG wind turbines with virtual inertial control, PLL affects system damping mainly by affecting the participation of virtual inertia in the system. The smaller the PI parameters of PLL are, the smaller the participation factor of virtual inertia control state variables in the interarea oscillation mode is, and the bigger the electromechanical oscillation mode damping ratio is. Simulation results verify the reasonableness of the established model and the possibility that virtual inertia control may cause system small-signal stability to deteriorate in multimachine system.
Auteurs: Jing Ma;Yang Qiu;Yinan Li;Weibo Zhang;Zhanxiang Song;James S. Thorp;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2094 - 2105
Editeur: IEEE
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» Research Papers: Writing Tips and Top-Tier Targets
Résumé:
As a part of each graduate program study, graduate students need to conduct research in a specific field and, most importantly, publish the results of their work in journals and conference publications. While this might sound easy to some graduate students, it may be the most challenging task for many, specifically those in the early years of their studies. Particularly, students have questions regarding transferring the results of their work from a "report" into a research paper, writing high-quality research papers, and how to choose among the various journals and conference publications in their fields. Very often, many students have good results but they have a difficult time publishing them.
Auteurs: Mahdi Nikdast;
Apparue dans: IEEE Potentials
Date publication: 05.-2017, volume: 36, issue:3, pages: 26 - 29
Editeur: IEEE
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» Residual Stress and Pop-Out Simulation for TSVs and Contacts in Via-Middle Process
Résumé:
In the via-middle process of 3-D integrated circuit manufacturing, through-silicon via (TSV) annealing causes mechanical stress not only to its surrounding structures, including liner and landing pad, but also the contacts nearby. This process may result in a noticeable pop-out in TSVs and/or contacts, thus complicating the subsequent chemical mechanical polishing (CMP). In addition, residual stress may cause delamination or crack. In this paper, we conducted detailed simulations of the residual stress and pop-out mechanisms for TSVs and neighboring contacts. Our primary focus was on the interplay of TSV-induced and contact-induced stresses and their combined impact on pop-out height. In addition, we conducted a sensitivity analysis of key parameters, including distance, plasticity, annealing temperature, and the distribution of neighboring contacts. This paper showed that these parameters notably affect the stress and the pop-out of TSVs and contacts. This in turn is expected to complicate the subsequent CMP steps. Finally, we applied the linear superposition method to predict stress and validated its accuracy by comparing the results with finite element analysis simulation. The results of the comparison demonstrated that the superposition method was accurate. Therefore, it could be used to predict the stress for full-chip design.
Auteurs: Can Rao;Tongqing Wang;Yarui Peng;Jie Cheng;Yuhong Liu;Sung Kyu Lim;Xinchun Lu;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 05.-2017, volume: 30, issue:2, pages: 143 - 154
Editeur: IEEE
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» Retention-Aware DRAM Assembly and Repair for Future FGR Memories
Résumé:
Refresh operations consume substantial energy and bandwidth in high-density dynamic random-access memory (DRAM) memory. The trend of increasing refresh overhead limits the scalability of DRAM memory that refreshes all cells at the same rate, because the refresh rate setting depends on the worst-case weak cell manufactured in unstable process technology. To cope with this issue, fine-grained refresh (FGR) is proposed to eliminate the unnecessary refresh operations caused by minor weak cells. Even JEDEC’s DDR4 DRAM specification announces the support of FGR, which is likely to evolve and become a standard in future DRAM. Unfortunately, according to our key observation, the effectiveness of FGR is greatly confined by the procedure of refresh-oblivious device integration because all memory devices within a module have to be controlled and refreshed in a lockstep way after the step of assembly. In this paper, we are the first to propose a holistic FGR-oriented DRAM optimization framework, retention-aware DRAM assembly and repair (RADAR), to enhance the effectiveness of FGR in DRAM modules. RADAR includes two novel techniques applicable at the stage of DRAM assembly. The first one is retention-aware device clustering that integrates the “compatible” devices to achieve low refresh rate through a preassembly testing and retention-aware matching method. The second technique, Microfix, exploits the hierarchical DRAM array structure and its redundancy to fix critical weak DRAM rows through fine-grained row and subarray remapping. With this optimization architecture, RADAR, the refresh overhead of DRAM dual in-line memory modules can be dramatically reduced as implied in the experiments.
Auteurs: Ying Wang;Yin-He Han;Cheng Wang;Huawei Li;Xiaowei Li;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 705 - 718
Editeur: IEEE
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» Revolutionizing Wearables for 5G: 5G Technologies: Recent Developments and Future Perspectives for Wearable Devices and Antennas
Résumé:
Wearable devices present an increasingly attractive solution for numerous applications in sectors ranging from the military to medicine to consumer electronics. They will also play an integral role in the imminent fifth-generation (5G) networks, which are expected to operate with higher bit rates and lower outage probabilities in smaller microcells and picocells covering broader areas than fourth-generation (4G) or older technologies. In addition, beam reconfigurability and beamforming are expected to facilitate spectral and energy efficiencies at both the mobile device and base station levels. In overcoming the limitations of current 4G systems, the new features and capabilities envisioned for 5G networks will radically change applications in transportation, health care, smart homes, and wireless robots, among many others [1], [2].
Auteurs: Nur Farahiyah Mohamad Aun;Ping Jack Soh;Azremi Abdullah Al-Hadi;Mohd Faizal Jamlos;Guy A.E. Vandenbosch;Dominique Schreurs;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 108 - 124
Editeur: IEEE
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