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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 05-2017 trié par par titre, page: 9
» Supply Chain Security: A Classification of Practices and an Empirical Study of Differential Effects and Complementarity
Résumé:
Supply chain security (SCS) breaches (a form of supply chain risk) are distressing supply chains and they have the potential to engender acute pain on the society at large. To counteract such breaches, international bodies, nations, societies, industries, and firms have instituted several countermeasures in the form of standards and respective practices. Given that not all incidences/breaches can be averted, the risk management literature advocates that firms should adopt practices that can thwart incidences/breaches and practices that can provide a swift response once an incident/breach is detected in order to contain damages, ease the pain, and restore operations. Resting on the risk management literature and interactions with professionals, we classify SCS management practices into four categories based on their intent (i.e., detection, prevention, response, and mitigation) and operationalize each via multiple indicators. We then test the relative efficacy of these practices to explain SCS performance using responses from 462 firms operating in the United States and Italy.
Auteurs: Guanyi Lu;Xenophon Koufteros;Lorenzo Lucianetti;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 05.-2017, volume: 64, issue:2, pages: 234 - 248
Editeur: IEEE
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» Suppressing Wind Turbine Signatures in Weather Radar Observations
Résumé:
Unwanted radar echoes, colloquially referred to as “clutter,” impede the mission effectiveness of radar systems. Depending on radar's application, clutter examples can include weather, buildings, vegetation, and more. Techniques to mitigate clutter and improve the performance of radar systems are continuously being developed and refined. In this paper, wind turbines used for commercial power generation, which present a Doppler velocity signature that is time-varying, are considered a source of radar clutter. A wind turbine clutter mitigation technique is developed for fixed-pointing weather radar applications, approximating the turbine's radar signature as a cyclostationary process. The cyclostationary model for the wind turbine and the suppression technique is then validated using observations of wind turbines and precipitation.
Auteurs: Robert M. Beauchamp;V. Chandrasekar;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2546 - 2562
Editeur: IEEE
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» Suppression of Efficiency Roll-Off in Fluorescent Organic Light-Emitting Devices Through Charge Carriers and Excitons Management
Résumé:
In this paper, a novel design for the emission layer of the fluorescent organic light-emitting devices is presented to suppress the efficiency roll-off and maintain the high efficiency at both low and high current regimes. In the emission layer, the emitter material is blended with a manager or host material with proper charge carrier transporting and excitonic energy levels. The charge carriers and excitons undergo a carefully designed route in this manager–emitter blend so that the triplet excitons always contribute positively to the efficiency through triplety–triplet annihilation (TTA), and the competing mechanisms are severely weakened. The required characteristics of the emitter and host materials for the proper functioning of the proposed strategy are completely discussed in this paper. The proposed scheme is verified through detailed numerical simulations, and it is shown that the efficiency roll-off can be effectively suppressed. The overall efficiency depends on the TTA yield in producing singlet excitons. For the yield of 0.5, an internal quantum efficiency of 50% at the current density of 10 mAcm $^{-2}$ is computed, which increases as the triplet density increases reaching the value of 58% at the current density of 1 Acm $^{-2}$ .
Auteurs: H. Soofi;S. Saeidi;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2330 - 2337
Editeur: IEEE
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» Surf's Up! Ride the Volunteer μWave
Résumé:
Advertisement, IEEE.
Auteurs: Andy Morishita;Jonathan Dang;Tyler Chun;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 90 - 94
Editeur: IEEE
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» SurfCuit: Surface-Mounted Circuits on 3D Prints
Résumé:
The SurfCuit system integrates circuits into 3D prints by mounting them on the printed surface. SurfCuit does not require tedious circuit casing design or expensive setups, allowing users to build complex, highly conductive circuit patterns for consumer-level desktop fused decomposition modeling (FDM) 3D printers and thus expediting the process of circuit construction for 3D models.https://extras.computer.org/extra/mcg2017030052s1.mp4
Auteurs: Nobuyuki Umetani;Ryan Schmidt;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 52 - 60
Editeur: IEEE
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» Survey on Real-Time Networks-on-Chip
Résumé:
Multi-Processor Systems-on-Chip (MPSoCs) have emerged as an evolution trend to meet the growing complexity of embedded applications with increasing computation parallelism. Particularly, real-time applications make out a significant portion of the embedded field. Networks-on-Chip (NoCs) are the backbone of communications in an MPSoC platform. However, the use of NoCs in real-time systems imposes complex constraints on the overall design. This paper discusses the challenges faced, when designing NoCs for real-time applications. Contributions in this area are surveyed on the level of guaranteed Quality-of-Service (QoS) support, adaptivity, and energy efficient techniques. Furthermore, the evaluation methodologies and experimental performance measurements of real-time NoCs are examined. This survey provides a comprehensive overview of existing endeavors in real-time NoCs and gives an insight towards future promising research points in this field.
Auteurs: Salma Hesham;Jens Rettkowski;Diana Goehringer;Mohamed A. Abd El Ghany;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1500 - 1517
Editeur: IEEE
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» SVM-Based System for Prediction of Epileptic Seizures From iEEG Signal
Résumé:
Objective: This paper describes a data-analytic modeling approach for the prediction of epileptic seizures from intracranial electroencephalogram (iEEG) recording of brain activity. Even though it is widely accepted that statistical characteristics of iEEG signal change prior to seizures, robust seizure prediction remains a challenging problem due to subject-specific nature of data-analytic modeling. Methods: Our work emphasizes the understanding of clinical considerations important for iEEG-based seizure prediction, and proper translation of these clinical considerations into data-analytic modeling assumptions. Several design choices during preprocessing and postprocessing are considered and investigated for their effect on seizure prediction accuracy. Results: Our empirical results show that the proposed support vector machine-based seizure prediction system can achieve robust prediction of preictal and interictal iEEG segments from dogs with epilepsy. The sensitivity is about 90–100%, and the false-positive rate is about 0–0.3 times per day. The results also suggest that good prediction is subject specific (dog or human), in agreement with earlier studies. Conclusion : Good prediction performance is possible only if the training data contain sufficiently many seizure episodes, i.e., at least 5–7 seizures. Significance: The proposed system uses subject-specific modeling and unbalanced training data. This system also utilizes three different time scales during training and testing stages.
Auteurs: Han-Tai Shiao;Vladimir Cherkassky;Jieun Lee;Brandon Veber;Edward E. Patterson;Benjamin H. Brinkmann;Gregory A. Worrell;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 1011 - 1022
Editeur: IEEE
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» SWIM: The First Spaceborne Wave Scatterometer
Résumé:
This paper provides an overview of the surface waves investigation and monitoring (SWIM) instrument which will be one of the two payload instruments carried by China France Oceanography SATellite (CFOSAT) with a planned launch date in mid-2018. SWIM is a real aperture wave scatterometer operated at near-nadir incidence angles and dedicated to the measurement of directional spectra of ocean waves. The SWIM flight model is currently being assembled and tested, its performance is being assessed and its prototype data processing algorithm is being developed. The aim of this paper is to provide a complete overview on the motivations and scientific requirements of this mission, together with a description of the design and characteristics of the SWIM instrument, and the analysis of its expected performances based on a prelaunch study. An end-to-end simulator has been developed to evaluate the quality of the data products, thus allowing the overall performance of the instrument to be assessed. Simulations run with two subsets of full orbit subsets show that the performances of the instrument and the inversion algorithms will meet the scientific requirements for the mission.
Auteurs: Danièle Hauser;Céline Tison;Thierry Amiot;Lauriane Delaye;Nathalie Corcoral;Patrick Castillan;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 3000 - 3014
Editeur: IEEE
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» Switched Fuzzy-PD Control of Contact Forces in Robotic Microbiomanipulation
Résumé:
Force sensing and control are of paramount importance in robotic micromanipulation. A contact force regulator capable of accurately applying mechanical stimuli to a live Drosophila larva could greatly facilitate mechanobiology research on Drosophila and may eventually lead to novel discoveries in mechanotransduction mechanisms of neuronal circuitries. In this paper, we present a novel contact force control scheme implemented in an automated Drosophila larvae micromanipulation system, featuring a switched fuzzy to proportional-differential (PD) controller and a noise-insensitive extended high gain observer (EHGO). The switched fuzzy-PD control law inherits the fast convergence of fuzzy control and overcomes its drawbacks such as large overshoot and steady-state oscillation. The noise-insensitive EHGO can reliably estimate system modeling errors and is robust to force measurement noises, which is advantageous over conventional high gain observers (sensitive to signal noises). Force control experiments show that, compared to a proportional-integral-differential (PID) controller, this new force control scheme significantly enhances the system dynamic performance in terms of rising time, overshoot, and oscillation. The developed robotic system and the force control scheme will be applied to mechanical stimulation and fluorescence imaging of Drosophila larvae for identifying new mechanotransduction mechanisms.
Auteurs: Weize Zhang;Xianke Dong;Xinyu Liu;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 1169 - 1177
Editeur: IEEE
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» Synchronizing Torque Impacts on Rotor Speed in Power Systems
Résumé:
Renewables are increasingly replacing power from conventional generators. Renewable power injected through power electronic converters lacks the fundamental electric torque components. Electric torque components have an important role in determining the behavior of conventional machines in the network. The influence of this factor becomes more notable in power systems with reduced inertia. Hence, questions arise on, how can synchronizing torque basically contribute to the rotor speed deviation and eventually the system frequency and if there is a potential for using the steady state synchronizing torque coefficient (STC) to achieve acceptable frequency operating points. This paper calculates the steady state STC matrix by using the multimachine Heffron-Philips model in conjunction with the network admitance matrix. Accordingly, it investigates the impact of the generator location and reactive power output on the STC matrix. It demonstrates how this impact manifests in the generator rotor speed deviation. Eventually, the significance of the STC from the system frequency perspective is assessed.
Auteurs: Mostafa Bakhtvar;Eknath Vittal;Kuan Zheng;Andrew Keane;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1927 - 1935
Editeur: IEEE
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» Synthesis and Design of Harmonic-Suppressed Wideband Bandpass Filters With Mixed Modified Richard’s Transformations
Résumé:
A new technique using mixed frequency transformations has been proposed for wideband bandpass filter design to suppress the harmonic passband. Different modified Richard’s transformations (MRTs) are used herein to maintain an almost exact in-band transformation but different out-of-band characteristics. Thus, the original in-band filtering response can be transformed through a uniform pattern, while the harmonic resonance of every single resonator is relocated at some desired places. The synthesis procedure of the filter includes deriving the equivalent LC circuit, calculating MRTs, transforming the LC circuit into its transmission line counterpart by mixed MRTs. A design example has been demonstrated to strongly support the proposed technique in the experiment.
Auteurs: Runqi Zhang;Sha Luo;Lei Zhu;Li Yang;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 455 - 457
Editeur: IEEE
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» Synthesis of Cyberphysical Digital-Microfluidic Biochips for Real-Time Quantitative Analysis
Résumé:
Considerable effort has recently been directed toward the implementation of molecular bioassays on digital-microfluidic biochips (DMFBs). However, today’s solutions suffer from the drawback that multiple sample pathways are not supported and on-chip reconfigurable devices are not efficiently exploited. As a result, impractical manual intervention is needed to process protocols for gene-expression analysis. To overcome this problem, we first describe our benchtop experimental studies to understand gene-expression analysis and its relationship to the biochip design specification. We then introduce an integrated framework for quantitative gene-expression analysis using DMFBs. The proposed framework includes: 1) a spatial-reconfiguration technique that incorporates resource-sharing specifications into the synthesis flow; 2) an interactive firmware that collects and analyzes sensor data based on quantitative polymerase chain reaction; and 3) a real-time resource-allocation scheme that responds promptly to decisions about the protocol flow received from the firmware layer. This framework is combined with cyberphysical integration to develop the first design-automation framework for quantitative gene expression. Simulation results show that our adaptive framework efficiently utilizes on-chip resources to reduce time-to-result without sacrificing the chip’s lifetime.
Auteurs: Mohamed Ibrahim;Krishnendu Chakrabarty;Kristin Scott;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 733 - 746
Editeur: IEEE
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» Synthesis of Regular Expressions Revisited: From PSL SEREs to Hardware
Résumé:
We revisit the specification of control circuits and protocols written as regular expressions, and propose a synthesizable subset of the sequences that can be written in the property specification language and system Verilog assertions standards. We give a formal semantics of the sequence operators that can directly be interpreted in terms of circuits, and provide a modular method to achieve the automatic generation of compliant hardware from specifications written as temporal sequences. The method also generates assertions to check the completeness and consistency of the specifications. Results obtained on classical benchmarks show the efficiency of our technique. Finally, we discuss the applications of our prototype tool in an assertion-based verification flow.
Auteurs: Fatemeh Negin Javaheri;Katell Morin-Allory;Dominique Borrione;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 869 - 882
Editeur: IEEE
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» System Cost Minimization in Cloud RAN With Limited Fronthaul Capacity
Résumé:
Cloud radio access network (C-RAN) is emerging as a potential alternative for the next generation RAN by merging RAN and cloud computing together. In this paper, we consider the baseband unit (BBU) pool of C-RAN as a collection of virtual machines (VMs). We allow each user equipment (UE) to associate with multiple VMs in the BBU pool, and each remote radio head (RRH) can only serve a limited number of UEs. Under this model, we jointly optimize the VM activation in the BBU pool and sparse beamforming in the coordinated RRH cluster, which is constrained by limited fronthaul capacity, to minimize the system cost of C-RAN. We formulate this problem as a mixed-integer nonlinear programming problem, and then propose efficient methods to optimize the number of active VMs, as well as the sparse beamforming vectors. Moreover, we derive a closed-form solution for the beamforming vectors. Simulation results suggest that our proposed algorithms have better performance than the benchmark algorithms in terms of both system cost and robustness.
Auteurs: Jianhua Tang;Wee Peng Tay;Tony Q. S. Quek;Ben Liang;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3371 - 3384
Editeur: IEEE
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» System Design of a 2.75-mW Discrete-Time Superheterodyne Receiver for Bluetooth Low Energy
Résumé:
This paper introduces a system-level approach to develop the first-ever fully discrete-time (DT) superheterodyne receiver (RX) for Internet-of-Things applications, such as Bluetooth low energy (BLE). It exploits fast switching speed and low internal capacitances of deep-nanoscale CMOS devices to realize a high intermediate-frequency (IF) architecture based on switched-capacitor-based charge-domain bandpass filtering. Power consumption is minimized by aggressively reducing the size of MOS devices and judiciously applying a sampling-rate decimation. The resultant increase in the flicker noise is mitigated by placing the IF frequency beyond the flicker corner frequency. Likewise, the decimation-induced aliasing is mitigated by DT filtering of preceding stages. The BLE RX is fully standard-compliant and achieves a record-low-power consumption of 2.75 mW (including its local oscillator) while delivering the state-of-the-art performance: 6.5-dB noise figure and −19-dBm third-order input intercept point, with a direct antenna connection and thus without the typical external bandpass filters.
Auteurs: Sandro Binsfeld Ferreira;Feng-Wei Kuo;Masoud Babaie;Sergio Bampi;Robert Bogdan Staszewski;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1904 - 1913
Editeur: IEEE
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» System-Level Design Considerations for Digital Pre-Distortion of Wireless Base Station Transmitters
Résumé:
Over the past 25 years or so there has been much interest in the use of digital pre-distortion (DPD) techniques for the linearization of RF and microwave power amplifiers. In this paper, we describe the important system and hardware requirements for the four main subsystems found in the DPD linearized transmitter: RF/analog, data converters, digital signal processing, and the DPD architecture and algorithms, and illustrate how the overall DPD system architecture is influenced by the design choices that may be made in each of these subsystems. We shall also consider the challenges presented to future applications of DPD systems for wireless communications, such as higher operating frequencies, wider signal bandwidths, greater spectral efficiency signals, resulting in higher peak-to-average power ratios, multiband and multimode operation, lower power consumption requirements, faster adaption, and how these affect the system design choices.
Auteurs: John Wood;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1880 - 1890
Editeur: IEEE
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» Systematic Decomposition of the Positive Bias Stress Instability in Self-Aligned Coplanar InGaZnO Thin-Film Transistors
Résumé:
We propose an experimental method to decompose the positive gate-bias stress (PBS)-induced threshold voltage shift ( $Delta {V}_{mathsf {th}})$ of amorphous InGaZnO (a-IGZO) thin-film transistors (TFTs) into the contributions of distinct degradation mechanisms. Top-gate self-aligned coplanar structure TFTs are used for this letter. Stress-time-divided measurements, which combine the subgap density-of-states (DOS) extraction and the analysis on recovery characteristics, are performed to separate the $Delta {V}_{mathsf {th}}$ components. Change in excess oxygen ( $text{O}_{mathsf {ex}})$ -related DOS is clearly observed, and $Delta {V}_{mathsf {th}}$ by PBS is quantitatively decomposed into the contributions of the active $text{O}_{mathsf {ex}}$ , and the deep and shallow gate insulator traps. The quantitative decomposition of PBS-induced $Delta {V}_{mathsf {th}}$ provides physical insight and key guidelines for PBS stability optimization of a-IGZO TFTs.
Auteurs: Sungju Choi;Juntae Jang;Hara Kang;Ju Heyuck Baeck;Jong Uk Bae;Kwon-Shik Park;Soo Young Yoon;In Byeong Kang;Dong Myong Kim;Sung-Jin Choi;Yong-Sung Kim;Saeroonter Oh;Dae Hwan Kim;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 580 - 583
Editeur: IEEE
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» Túum: Test Model for Native Mobile Applications
Résumé:
Nowadays the testing area in mobile application is strongly studied due to the increasing use of mobile devices and the development of mobile applications with different approaches, such as multimedia, games, information, among others. Mobile applications must consider several quality aspects such as optimizing resource use and usability to help meet targets. To accomplish this, several authors have proposed testing models. However, these models do not consider important aspects such as diversity of devices and do not cover the entire application developing process. This article describes a testing model for native mobile applications, characterized by specific tools and steps that contribute to measure aspects of internal and external quality such as failures or code optimization and usability recommendations. In addition, our model is attached to the software development process, from requirements to system testing, which facilitates its implementation and helps timely detection and correction of errors before continuing with the software development cycle.
Auteurs: Humberto Sanchez Martinez;Maria de Lourdes Hernandez Rodriguez;Eduardo Lopez Dominguez;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 994 - 1000
Editeur: IEEE
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» Table of contents
Résumé:
This is the 5st issue of the IEEE Latin America Transactions of the year 2017. Volume 15 Issue 5, Mayl 2017
Auteurs: Mirela Sechi Moretti Annoni Notare;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 767 - 768
Editeur: IEEE
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» Target Detection for Polarized Hyperspectral Images Based on Tensor Decomposition
Résumé:
In the past decades, with the development of polarized hyperspectral imaging system, target detection and recognition for polarized hyperspectral images (PHSIs) have attracted more and more attention. Most conventional target detection algorithms of PHSI are based on the Stokes vector, which mainly take advantage of the spectral information, and ignore the continuous variability of polarized dimension, being similar to spectrum. In fact, the PHSI include multidimensional features of polarization, spectrum, space, and radiation, and these provide more discriminable information about target and background than traditional spectrum or intensity ones. Hence, tensor, which can keep the complete information of PHSI, is introduced to represent such high-dimensional data. In this letter, the tensor canonical polyadic (CP) decomposition is adopted to extract the spectral and polarized features. There are two ways to realize the target detection through CP decomposition. One is to construct a fourth-order tensor matched filtering (FTMF), and FTMF is applied to the original data directly without extracting the Stokes vector. The other is to reconstruct the PHSI into a new 3-D data, then matched filter algorithm of hyperspectral image is applied to this data to detect the targets, for short CPMF. The experimental results show that the proposed methods achieve the joint utilization of spectrum and polarization and are more suitable and effective for the target detection of the PHSI.
Auteurs: Jian Tan;Junping Zhang;Ye Zhang;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 674 - 678
Editeur: IEEE
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» Target Detection in High-Resolution SAR Images via Searching for Part Models
Résumé:
In high-resolution synthetic aperture radar (SAR) images, targets are often spatially spread, and some separated regions of one target may be detected as different potential targets. The target should be represented by a part model to combine the separated regions into one target. In this letter, a part often means a separated region, and the part model obtains a hierarchical combination of the other parts. Moreover, the bottom hierarchy consists of strong scatters in the local SAR image, which are searched based on compressed intensities. The middle hierarchy consists of parts, which are generated based on connectivity and similarity of scatters in the bottom hierarchy. The top hierarchy delineates the relationship of parts in the middle hierarchy. A search method is designed based on the different features of the elements in each hierarchy. Consequently, the proposed algorithm combines different traits of targets to improve detection, and unites the separated regions of one target in the top hierarchy. This algorithm is validated by SAR images with different resolutions and scenes.
Auteurs: Haiyi Yang;Zongjie Cao;Yiming Pi;Shuo Liu;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 664 - 668
Editeur: IEEE
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» Targeting Effects on the Volume of the Focused Ultrasound-Induced Blood–Brain Barrier Opening in Nonhuman Primates In Vivo
Résumé:
Drug delivery to subcortical regions is susceptible to the blood–brain barrier (BBB) impeding the molecular exchange between the blood stream and the brain parenchyma. Focused ultrasound (FUS) coupled with the administration of microbubbles has been proved to open the BBB locally, transiently, and noninvasively both in rodents and in nonhuman-primates (NHPs). The development of this disruption technique independent of MRI monitoring is of primordial importance yet restrained to the targeting optimization. This paper establishes the linear relationship of the incidence angle with the volume of BBB opening ( $V_{mathrm{BBB}}$ ) and the peak negative pressure when sonicating the caudate nucleus and the putamen region of five NHPs. In addition, the effect of central nervous system structures on the opening morphology is evaluated by identification of the gray-to-white-matter ratio at the opening site. Finally, the targeting accuracy is assessed through the estimation of the geometric and angle shift of the opening from the targeted region. Interestingly, results prove a monotonic increase of the opening volume with close to normal incidence angles. Moreover, 80.35% of the opening lies on gray-matter regions compared with only 19.41% attributed to the white matter. The opening was found to be shifted axially, toward the transducer, and laterally with an average angle shift of 4.5°. Finally, we were capable of showing reproducibility of targeting accuracy with the same stereotactic and ultrasonic parameters. This paper documents the a priori prediction of the opening volume through manipulation of the angle and pressure as well as establishing the predictability, accuracy, and safety of FUS-induced BBB opening in NHPs.
Auteurs: Maria Eleni Marilena Karakatsani;Gesthimani Mania Samiotaki;Matthew E. Downs;Vincent P. Ferrera;Elisa E. Konofagou;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 798 - 810
Editeur: IEEE
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» Teaching Experiences Inspire, Students Aspire at IMS2017
Résumé:
Provides a notice of upcoming conference events of interest to practitioners and researchers.
Auteurs: Cheryl Sato Ishii;Derek Ah Yo;Reyn Mukai;Steven Brown;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 77 - 81
Editeur: IEEE
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» Temperature Compensation of Silicon Lamé Resonators Using Etch Holes: Theory and Design Methodology
Résumé:
We present a new approach to the temperature compensation of MEMS Lamé resonators, based on the combined effect of the doping concentration and of the geometry of etch holes on the equivalent temperature coefficients of silicon. To this purpose, we develop and validate an analytical model which describes the effect of etch holes on the temperature stability of Lamé resonators through comparison with experiments available in the literature and finite-element method (FEM) simulations. We show that two interesting regions of the design space for Lamé resonators exist, where a cancellation of the first-order temperature coefficient of the resonance frequency is possible: [100]-oriented silicon with n-doping of $2.5~cdot 10^{19}$ cm $^{-3}$ , and [110]-oriented silicon with p-doping higher than $1.4~cdot 10^{20}$ cm $^{-3}$ .
Auteurs: Luca Luschi;Giuseppe Iannaccone;Francesco Pieri;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 879 - 887
Editeur: IEEE
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» Temperature-Tolerant Wavelength-Setting and -Stabilization in a Polymer-Based Tunable DBR Laser
Résumé:
In this paper, we present a method of self-detection of mode hops in a distributed Bragg reflector tunable laser using the voltage drop in the active section as a monitoring signal. Based on this method, a wavelength setting and stabilization algorithm that is tolerant to temperature variations is proposed. Wavelength locking for a period of more than seven days with an accuracy better than ±1.25 GHz has been achieved, meeting the ITU-T standard for 25 GHz channel spacing. Under forced changes in the operation temperature from 15° to 60°, with variations of 0.1°/s, the maximum allowed deviation of ±2.5 GHz for the ITU-T standard with 50 GHz channel spacing was kept.
Auteurs: Magnus Happach;David de Felipe;Victor Nicolai Friedhoff;Moritz Kleinert;Crispin Zawadzki;W. Rehbein;Walter Brinker;Martin Möhrle;Norbert Keil;Werner Hofmann;Martin Schell;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1797 - 1802
Editeur: IEEE
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» Temporal Probabilistic Shaping for Mitigation of Nonlinearities in Optical Fiber Systems
Résumé:
In this paper, finite state machine sources (FSMSs) are used to shape quadrature amplitude modulation (QAM) for nonlinear transmission in optical fiber communication systems. The previous optimization algorithm for FSMSs is extended to cover an average power constraint, thus enabling temporal optimization with multiamplitude constellations output, such as QAM. The optimized source results in increased received SNR and, thereby, increased achievable information rates (AIR)s under memoryless assumption. The AIR is increased even further when taking the channel and transmitter memory into account via trellis processing at the receiver. Significant gains are reported in the highly nonlinear region of transmission for an FSMS of up to second order and 16QAM and particularly for unrepeated transmission. At the optimal launch power of WDM transmission, the FSMS order needs to be increased further in order to notably outperform previous probabilistic shaping schemes.
Auteurs: Metodi P. Yankov;Knud J. Larsen;Søren Forchhammer;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1803 - 1810
Editeur: IEEE
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» The "Good" Blackout: The Northeast Power Failure of 9 November 1965 [History]
Résumé:
On the night of 9 November 1965, the northeastern United States and the province of Ontario suffered an electric power failure unprecedented in the history of the industry up until that time. An estimated 30 million Americans and Canadians were directly affected in an area encompassing about 80,000 mi2, as shown in Figure 1. Full restoration of the power took up to 13 h. The event immediately became front-page news around the world, and photographs and films of a blacked-out New York City formed the root of endless editorials, speculations, and conspiracy theories.
Auteurs: George C. Loehr;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 05.-2017, volume: 15, issue:3, pages: 84 - 96
Editeur: IEEE
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» The Discrete Dantzig Selector: Estimating Sparse Linear Models via Mixed Integer Linear Optimization
Résumé:
We propose a novel high-dimensional linear regression estimator: the Discrete Dantzig Selector, which minimizes the number of nonzero regression coefficients subject to a budget on the maximal absolute correlation between the features and residuals. Motivated by the significant advances in integer optimization over the past 10–15 years, we present a mixed integer linear optimization (MILO) approach to obtain certifiably optimal global solutions to this nonconvex optimization problem. The current state of algorithmics in integer optimization makes our proposal substantially more computationally attractive than the least squares subset selection framework based on integer quadratic optimization, recently proposed by Bertsimas et al. and the continuous nonconvex quadratic optimization framework of Liu et al.. We propose new discrete first-order methods, which when paired with the state-of-the-art MILO solvers, lead to good solutions for the Discrete Dantzig Selector problem for a given computational budget. We illustrate that our integrated approach provides globally optimal solutions in significantly shorter computation times, when compared to off-the-shelf MILO solvers. We demonstrate both theoretically and empirically that in a wide range of regimes the statistical properties of the Discrete Dantzig Selector are superior to those of popular $ell _{1}$ -based approaches. We illustrate that our approach can handle problem instances with $p =10,!000$ features with certifiable optimality making it a highly scalable combinatorial variable selection approach in sparse linear modeling.
Auteurs: Rahul Mazumder;Peter Radchenko;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3053 - 3075
Editeur: IEEE
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» The Benefits of Joining a Multidisciplinary Research Team
Résumé:
Exciting research challenges often present themselves as complex problems-they are inherently difficult to understand and require multiple domains of expertise to solve. As a result, teamwork is becoming the everyday norm in most professional settings and is often required when studying topical problems (e.g., autonomous vehicles, cyberphysical, renewable energy, among others). For students, learning to operate within, and eventually lead, a team is a necessary and valuable skill that will benefit them throughout their professional lives.
Auteurs: Logan O. Mailloux;Michael R. Grimaila;Douglas D. Hodson;Gerald B. Baumgartner;
Apparue dans: IEEE Potentials
Date publication: 05.-2017, volume: 36, issue:3, pages: 18 - 22
Editeur: IEEE
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» The Bullwhip Effect in an Online Retail Supply Chain: A Perspective of Price-Sensitive Demand Based on the Price Discount in E-Commerce
Résumé:
This paper investigates the difference in bullwhip effects in online and offline retail supply chains, offering insights into how frequent price discounts in e-commerce influence the bullwhip effect in the online retail supply chain. We consider a two-level online retail supply chain with a manufacturer and an online retailer in which the demand faced by the retailer is price sensitive and based on the price discount. Assuming that the online retailer employs an optimal order-up-to inventory policy with an optimal minimum mean-squared error forecasting technique, we derive the expression of the bullwhip effect in the online retail supply chain and make analysis and comparison. Finally, we develop a dual-channel supply chain model to directly observe the impact of price discounts in e-commerce on the bullwhip effect. The results suggest that price discounts in the online retail market generally amplify the bullwhip effect in the online retail supply chain, but in certain conditions, the bullwhip in the online supply chain may be smaller than that in the offline supply chain. We also find that the relationship between the lead time and the bullwhip effect in the online supply chain presents a distinctive feature contrary to the conclusions of previous studies. Based on the analysis, we develop important managerial insights regarding online retail supply chains.
Auteurs: Dandan Gao;Nengmin Wang;Zhengwen He;Tao Jia;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 05.-2017, volume: 64, issue:2, pages: 134 - 148
Editeur: IEEE
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» The Cluster Scattering in ZnMgO/ZnO Heterostructures With Three- and Five-Valley
Résumé:
The role of cluster scattering on electron transport properties of ZnMgO/ZnO heterostructures considering three- and five-valley conduction band models was investigated with an ensemble Monte Carlo program developed by us. The cluster scattering is modeled as an elastic collision, in which the electrons confined in ZnO well are scattered by MgZnO clusters. The interface roughness scattering, dislocation scattering, alloy disorder scattering, and phonon scattering are also taken into account in the simulation. For both energy band models, it is found that Mg composition fluctuation ( $eta $ ), the cluster size ( $xi $ ), and the 2-D electron gas sheet density (Ns) have a great impact on low-field mobility owing to the cluster scattering. But the low-field mobility of five-valley is slightly smaller than that of three-valley due to the increased total scattering. A further comparison of velocity-field transport characteristics shows that the cluster scattering is prevailing at low temperature, and it significantly decreases the electron drift velocity for both energy band models. Moreover, the threshold electric fields of these two models are both enhanced by approximately 10 kV/cm at 10 K with cluster scatteringconsidered. This paper is beneficial for designing ZnMgO/ZnO heterostructure devices.
Auteurs: Hongyan Chen;Ping Wang;Jingsi Cheng;ZhaoLing Li;Lixin Guo;Zhiyong Zhang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2148 - 2154
Editeur: IEEE
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» The CNN as a Guided Multilayer RECOS Transform [Lecture Notes]
Résumé:
There is a resurging interest in developing a neural-network-based solution to the supervised machine-learning problem. The convolutional neural network (CNN) will be studied in this lecture note. We introduce a rectified-correlations on a sphere (RECOS) [1] transform as a basic building block of CNNs. It consists of two main concepts: 1) data clustering on a sphere and 2) rectification. We then interpret a CNN as a network that implements the guided multilayer RECOS transform with two highlights. First, we compare the traditional single-layer and modern multilayer signal-analysis approaches, point out key areas that enable the multilayer approach, and provide a full explanation to the operating principle of CNNs. Second, we discuss how guidance is provided by labels through backpropagation (BP) in the training.
Auteurs: C.-C. Jay Kuo;
Apparue dans: IEEE Signal Processing Magazine
Date publication: 05.-2017, volume: 34, issue:3, pages: 81 - 89
Editeur: IEEE
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» The counterintuitive cloud [Reflections]
Résumé:
Until recently, the word data didn't require a modifier. But we passed a watershed moment when we started referring to big data. Apparently, that wasn't a sufficient description for some chunks of data, because people grasped for bolder terms, such as humongous data. Sadly, now, it appears that we have run out of appropriate adjectives. And yet data keeps getting bigger and bigger. . So instead of mentioning data, people have begun waving their hands and talking vaguely about the "cloud." This seems to be the perfect metaphor-a mystical vapor hanging over Earth, occasionally raining information on the parched recipients below. It is both unknowable and all-knowing. It answers all questions, if only we know how to interpret those answers.
Auteurs: Robert W. Lucky;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 25 - 25
Editeur: IEEE
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» The Design of 2-D Explicit Depth Extrapolators Using the Cauchy Norm
Résumé:
In this paper, we present a novel method for designing explicit wavefield extrapolators to perform both prestack and poststack depth migrations of seismic data. This method is achieved through the design of finite impulse response filters that perform the depth migration in the frequency-space (F-X) domain. The design method works on finding the regularized least square solution for the filter impulse response by using the Cauchy norm as the regularization cost function. This cost function offers an adaptive damping on the approximated filter impulse response coefficients yielding a more accurate approximation of the filter coefficients. It also insures the stability of the recursive migration process through which the designed filters will be used and prevent both over shooting and dampening of the wavenumber response of the filters designed. To test the designed filters, we then conducted poststack depth migration to the well-known SEG/EAGE salt model zero-offset data set, where subsalt structures were accurately migrated. The filters were also designed and used to perform prestack migration on the challenging Marmousi model data set successfully. The obtained results indicate that these filters can be used to perform stable and efficient prestack and poststack explicit wavefield extrapolations.
Auteurs: Abdullah F. Al-Battal;Wail A. Mousa;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 3029 - 3036
Editeur: IEEE
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» The Discrete Memoryless Interference Channel With One-Sided Generalized Feedback and Secrecy
Résumé:
We study the interference channel with one-sided generalized feedback and secrecy requirement. In our model Message 1 that is known just to Encoder 1 should be decoded by both receivers. Message 2—known only to Encoder 2—should be decoded by Decoder 2 and kept as secret as possible from Decoder 1. The uncertainty of Decoder 1 about Message 2 is measured by means of the equivocation rate. In addition, a noisy feedback is provided to Encoder 2. We derive an outer bound on the capacity-equivocation region for this model that is valid for the ”noisy cribbing” regime. The gap between this upper bound and the inner bound reported before is just in the Markov conditions satisfied by one of the auxiliary random variables. Furthermore, we consider a simplified causal cognitive interference model: the interference channel with a cribbing encoder. We show that when, conditioned on the input of Encoder 1, the interference channel is degraded our outer bound is tight thereby establishing the capacity-equivocation region for this case.
Auteurs: Shraga I. Bross;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2710 - 2725
Editeur: IEEE
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» The Effect of Pinned Photodiode Shape on Time-of-Flight Demodulation Contrast
Résumé:
An empirical investigation on improving the pinned photodiode (PPD) demodulation contrast by tailoring the geometry of the device is presented. Results of this TCAD simulation-based study are used to develop a structure especially suited for time-of-flight applications. In order to obtain a fair comparison between various PPD shapes, a square structure is adopted as a benchmark and all subsequent PPD geometries use the same process parameters. Five different PPD shapes are compared: 1) nominal square-shaped PPD; 2) triangular PPD; 3) constant-field PPD; 4) L-shaped constant-field PPD; and 5) proposed PPD. Device physics simulations are undertaken and the speed of each structure is evaluated on the basis of its demodulation contrast. It is shown that triangular and constant-field PPDs can provide significant improvement compared with a conventional square-shaped PPD, however they still lack effective lateral charge transfer in the final electron sorting stage. The final PPD proposed in this paper achieves this with a tailored PPD shape and doping gradient. In addition, the transfer gates are placed close to one another to make use of gate-induced fringe fields and thus improve the speed of electron sorting. Using these techniques, a PPD demodulation contrast of 61% is obtained at a frequency of 100 MHz, which is comparable to the contrast achieved in state-of-the-art photogate-based designs.
Auteurs: Terrence Cole Millar;Navid Sarhangnejad;Nikola Katic;Kyros Kutulakos;Roman Genov;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2244 - 2250
Editeur: IEEE
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» The Effects of a Robot Game Environment on Computer Programming Education for Elementary School Students
Résumé:
In the past, computer programming was perceived as a task only carried out by computer scientists; in the 21st century, however, computer programming is viewed as a critical and necessary skill that everyone should learn. In order to improve teaching of problem-solving abilities in a computing environment, extensive research is being done on teaching–learning methods, types of teaching software, the educational environment, and related tools. This paper, based on diverse experimental results, proposes an environment where elementary students can easily learn and practice computer programming. The proposed robot game environment used a tangible programming tool with which students can easily create robot programs, without learning syntax, and then validate their programming results; it can also provide various game activities to incite students’ interest. Observation of elementary school students placed in the robot game environment confirmed the tool’s usability and entertainment aspects, and students’ attitudes toward programming and their understanding of programming concepts improved.
Auteurs: Jaekwoun Shim;Daiyoung Kwon;Wongyu Lee;
Apparue dans: IEEE Transactions on Education
Date publication: 05.-2017, volume: 60, issue:2, pages: 164 - 172
Editeur: IEEE
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» The Emerging Genre of Data Comics
Résumé:
As we increasingly rely on data to understand our world, and as problems require global solutions, we need to effectively communicate that data to help people make informed decisions. The special Art on Graphics article explores the potential of data comics and their unique ability to communicate both data and context via compelling visual storytelling.
Auteurs: Benjamin Bach;Nathalie Henry Riche;Sheelagh Carpendale;Hanspeter Pfister;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 6 - 13
Editeur: IEEE
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» The Evolution of Springtime Water Vapor Over Beijing Observed by a High Dynamic Raman Lidar System: Case Studies
Résumé:
Raman lidar is an effective technique to retrieve the vertical distribution of atmospheric water vapor. For the first time, we present water vapor profiles retrieved by a high dynamic Raman lidar system over the Beijing area for representative cases in spring 2014, within the framework of the Aerosol Multi-wavelength Polarization Lidar Experiment project. In springtime, water vapor content over Beijing is generally low but with a strong daily variability. Its evolution is strongly coupled with winds and aerosols, with clouds also exerting a distinct impact. Northwesterly winds is found to be the most important factor impacting the temporal variability of water vapor mixing ratio (WVMR), and WVMR is found to be negatively correlated with wind speed. Moreover, we find that clouds tend to cause significant increases in the standard deviation of WMVR measurement, and relative humidity sharply increase below the cloud base. During a typical pollution episode, water vapor strongly covaries with aerosols due to hygroscopic growth effect and transport mechanism. Both water vapor and aerosols exhibit the highest variability within the planetary boundary layer (PBL), where the development and dissipation of haze mainly occur. Within the PBL, water vapor and aerosol concentration demonstrate different evolution features at different altitudes during the haze process, with a delayed increase and early decrease for higher altitudes. Back trajectory analysis using the hybrid single-particle Lagrangian trajectory model indicates that this phenomenon is most likely associated with different sources of the air mass at different altitudes.
Auteurs: Tianning Su;Jian Li;Jing Li;Chengcai Li;Yiqi Chu;Yiming Zhao;Jianping Guo;Yong Yu;Lidong Wang;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1715 - 1726
Editeur: IEEE
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» The Generation of Distribution Grid Models on the Basis of Public Available Data
Résumé:
The analysis and validation of innovative methods and concepts for distribution grids like smart-grid approaches require a realistic representation of the grid structure. However, the availability of real grid data for distribution grids is insufficient. Therefore, a method for the generation of model grids for all distribution grid voltage levels is developed, utilizing publicly available map data. Based on the information within the map data, the supply task as well as locations of substations can be derived. Dependent on the voltage level, different approaches have to be chosen, which are outlined in this contribution. These approaches take into account the specific requirements in the different voltage levels. The developed approaches enable the generation of exemplary grid structures in dependency of regional supply task specifications.
Auteurs: Jan Kays;André Seack;Theo Smirek;Fabian Westkamp;Christian Rehtanz;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2346 - 2353
Editeur: IEEE
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» The Human Contribution to Workplace Incidents: Addressing the Human Element in Electrical Safety
Résumé:
Studies by high-risk industries indicate that human error-the human element is often a contributing cause of incidents. In these industries, identifying and addressing the human element of safety is referred to as human performance. In this article, human-performance theory will be discussed, human-performance modes will be identified, and human-performance tools will be applied with the objective of changing and advancing the electrical safety culture.
Auteurs: Daniel Thomas Roberts;Mike Doherty;Lee A. Lane;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 05.-2017, volume: 23, issue:3, pages: 42 - 47
Editeur: IEEE
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» The IDE4L Project: Defining, Designing, and Demonstrating the Ideal Grid for All
Résumé:
The Purpose of the IDE4L project was to define, design, and demonstrate the ideal grid for all, with an active distribution network that integrates renewable energy sources (RESs) and new loads and guarantees the reliability of classical distribution networks. The active distribution network consists of the infrastructure of power delivery, active resources, and active network management (ANM) and combines passive infrastructure with active resources, ANM functionalities, and distribution automation information and communication technology infrastructure. Active distributed energy resources (DERs) include distributed generation (DG), demand, response, and storage. The concept of a commercial aggregator offering flexibility services is also integrated in an ANM.
Auteurs: Sami Repo;Ferdinanda Ponci;Davide Della Giustina;Amelia Alvarez;Cristina Corchero Garcia;Zaid Al-Jassim;Hortensia Amaris;Anna Kulmala;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 05.-2017, volume: 15, issue:3, pages: 41 - 51
Editeur: IEEE
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» The IEEE Engineer in Residence Program
Résumé:
Universities do an outstanding job of teaching the technical skills necessary to produce great engineers, but today's successful graduates also need good written and oral communications, teamwork, critical thinking, innovation, and entrepreneurial skills. How can a student obtain these additional skills while coping with a demanding course of study? One way is to intern at a company, but not everyone can take advantage of that opportunity. Another way is for students to have contact with professional engineers during their work on school projects.
Auteurs: Richard F. Toftness;
Apparue dans: IEEE Potentials
Date publication: 05.-2017, volume: 36, issue:3, pages: 33 - 35
Editeur: IEEE
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» The IGREENGrid Project: Increasing Hosting Capacity in Distribution Grids
Résumé:
Distributed Renewable Energy Sources (DRESs) are increasing rapidly in distribution grids, and their integration into the electricity system is one of the most relevant problems facing these networks. The objective of our project, IntegratinG Renewables in the EuropEaN electricity Grid (IGREENG rid), was to analyze and select the most promising research and development (R&D) solutions to this problem. For this purpose, four research institutions (Institute of Communications and Computer Systems of the National Technical University of Athens, Ricerca sul Sistema Energetico, Austrian Institute of Technology, and Tecnalia) and eight European utilities studied six large demonstration projects: Eberstalzell and Koestendorf (Energie AG Oberösterreich Netz and Saltzburg AG) in Austria; Proyecto de Redes Inteligentes del Corredor del HenarE in Spain, known as PEICE (Iberdrola Distribución Eléctrica and Gas Natural Fenosa); Sperchiada in Greece (Diacheiristis Ellinikou Diktyou Dianomis elektrikis Energeias); Isernia in Italy (e-distribuzione); Zukunftsnetze in Germany (Innogy SE); and Venteea in France (Enedis). IGREENG rid had a budget of €6.6 million, partially funded by the European Commission, and was in development for almost four years.
Auteurs: Jesus Varela;Nikos Hatziargyriou;Lisandro J. Puglisi;Marco Rossi;Andreas Abart;Benoit Bletterie;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 05.-2017, volume: 15, issue:3, pages: 30 - 40
Editeur: IEEE
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» The Influence of External Digital Elevation Models on PS-InSAR and SBAS Results: Implications for the Analysis of Deformation Signals Caused by Slow Moving Landslides in the Northern Apennines (Italy)
Résumé:
Advanced interferometric synthetic aperture radar (InSAR) postprocessing, like persistent scatterer InSAR (PS-InSAR), offers the possibility to investigate slow moving landslides, where standard interferometry is problematic. These advanced algorithms involve the analysis of a series of SAR acquisitions in both time and space. One input that requires particular attention for landslide applications is the external digital elevation model (DEM) that is used to correct the interferograms for the topographic phase term. When multiple elevation data sets are available for a given study area, it is difficult to decide which one should be used. In this paper, we test the sensitivity of PS-InSAR/Small Baseline Subset (SBAS) results to different DEMs. The study area is located in the Northern Apennines of Italy, where chaotic clay shales and fine-grained flysch host slow-moving earth flows and ancient rock slides. C-band (Envisat) and X-band (Cosmo-SkyMed) data are processed with different DEMs. We describe a simple framework to statistically analyze the influence of these models on the final PS-InSAR/SBAS results. We find that individual interferograms do not vary much depending on the DEM, while the results from PS-InSAR and SBAS analysis do vary. This is likely caused by the way the DEM error is estimated. We find also that the quality of the DEM is more important than the resolution and that X-band InSAR data are more sensitive to the choice of the DEM than C-band. The significance of the results is discussed with reference to two landslide areas.
Auteurs: Benedikt Bayer;David Schmidt;Alessandro Simoni;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2618 - 2631
Editeur: IEEE
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» The Influence of Fused Depth on the Side-Pumping Combiner for All-Fiber Lasers and Amplifiers
Résumé:
Among many types of side-pumping combiner, which have been reported recently, a fused tapered method, which is based on direct fusion of one or several tapered pump fibers to the surface of a signal fiber, seems to be a potential method because of its high coupling efficiency and the capability of handling high pump power up to kW-class. However, the fused depth is seldom taken into consideration in the numerical analysis, which is not in agreement with the real situation. We present the numerical and experimental investigation about the influence of fused depth on the performance of the side-pumping combiners for all-fiber lasers and amplifiers. The experimental results agree well with the theoretical analysis. The fused depth shows great importance and should be paid much attention when designing and developing a side-pumping combiner by the fused tapered method. We develop a fused tapered side-pumping combiner, which is successfully applied in a backward pumped fiber amplifier with a 1080 nm output power of 1.458 kW. Our results may also offer detailed suggestion and instruction of fabricating side-pumping combiner for high-power fiber laser applications.
Auteurs: Chengmin Lei;Zilun Chen;Jinyong Leng;Yanran Gu;Jing Hou;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1922 - 1928
Editeur: IEEE
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» The lost picture show
Résumé:
When the renowned cinematogr apher Emmanuel Lubezki began planning to shoot the wilderness drama The Revenant, he decided that to capture the stark, frozen beauty of a Canadian winter, he would use no artificial light, instead relying on sunlight, moonlight, and fire. He also planned to use traditional film cameras for most of the shooting, reserving digital cameras for low-light scenes. He quickly realized, though, that film "didn't have the sensitivity to capture the scenes we were trying to shoot, especially the things we shot at dawn and dusk," as he told an interviewer.
Auteurs: Marty Perlmutter;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 26 - 31
Editeur: IEEE
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» The MDS Queue: Analysing the Latency Performance of Erasure Codes
Résumé:
In order to scale economically, data centers are increasingly evolving their data storage methods from simple data replication to more powerful erasure codes, which provide the same level of reliability as replication, but at a significantly lower storage cost. In particular, it is well known that maximum-distance-separable (MDS) codes, such as Reed–Solomon codes, can achieve a target reliability with the maximum storage efficiency. While the use of codes for providing improved reliability in archival storage systems, where data is less frequently accessed (or so-called “cold data”), is well understood, the role of codes in storing more frequently accessed and active “hot data”, where latency is the key metric, is less clear. In this paper, we study data storage systems based on MDS codes through the lens of queueing theory, and term the queueing system arising under codes as an “MDS queue.” We provide lower and upper bounds on the average job latency for both centralized and decentralized versions of MDS queues. We also provide extensive simulations to corroborate our analysis as well as obtain additional insights.
Auteurs: Kangwook Lee;Nihar B. Shah;Longbo Huang;Kannan Ramchandran;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2822 - 2842
Editeur: IEEE
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» The Neural Mechanism Exploration of Adaptive Motor Control: Dynamical Economic Cell Allocation in the Primary Motor Cortex
Résumé:
Adaptive flexibility is of significance for the smooth and efficient movements in goal attainment. However, the underlying work mechanism of the cerebral cortex in adaptive motor control still remains unclear. How does the cerebral cortex organize and coordinate the activity of a large population of cells in the implementation of various motor strategies? To explore this issue, single-unit activities from the M1 region and kinematic data were recorded simultaneously in monkeys performing 3D reach-to-grasp tasks with different perturbations. Varying motor control strategies were employed and achieved in different perturbed tasks, via the dynamic allocation of cells to modulate specific movement parameters. An economic principle was proposed for the first time to describe a basic rule for cell allocation in the primary motor cortex. This principle, defined as the Dynamic Economic Cell Allocation Mechanism (DECAM), guarantees benefit maximization in cell allocation under limited neuronal resources, and avoids committing resources to uneconomic investments for unreliable factors with no or little revenue. That is to say, the cells recruited are always preferentially allocated to those factors with reliable return; otherwise, the cells are dispatched to respond to other factors about task. The findings of this study might partially reveal the working mechanisms underlying the role of the cerebral cortex in adaptive motor control, wherein is also of significance for the design of future intelligent brain–machine interfaces and rehabilitation device.
Auteurs: Wei Li;Yangyang Guo;Jing Fan;Chaolin Ma;Xuan Ma;Xi Chen;Jiping He;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 05.-2017, volume: 25, issue:5, pages: 492 - 501
Editeur: IEEE
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» The New MTT-S Journal Within a Journal [President's Column]
Résumé:
Auteurs: Dylan Williams;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 8 - 10
Editeur: IEEE
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» The PIT boss
Résumé:
Remember vinyl records? More specifically, do you remember the way vinyl records skip when they're dusty or scratched? Let me assume you're old enough to recall that annoyance, or perhaps you've experienced that vintage technology more recently. Now think back to when you got your first CD. Small and shiny, packing 74 minutes of music, it seemed magical, even more magical when you noticed that you could treat a disc pretty badly before physical damage affected the way it played. A lot of different kinds of engineering, of course, went into figuring out how to put music on a CD and play it back so reliably. There's hardware, including a laser, optics to focus it, and mechanical systems to move the laser and turn the disc. And there’s software-including pulse-code modulation, which turns regular samples of an analog signal into bits, and error-correcting codes, which make sure those bits don't get corrupted.
Auteurs: Tekla S. Perry;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 32 - 50
Editeur: IEEE
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» The Relationship Between the Traffic Flow and the Look-Ahead Cruise Control
Résumé:
There is a relationship between the traffic flow and the look-ahead control; they strongly interact with each other. Thus, this paper develops a design method for the look-ahead control, in which the influences of the traffic flow are considered. A sensitivity analysis of the parameter variation in the look-ahead control is also performed. If the traffic information is also considered in the look-ahead control, an undesirable side effect on the traffic flow may occur. An optimization method is also developed in order to calculate the optimum speed, which handles the individual vehicle energy optimization and its impact on the traffic flow. The method is illustrated through a complex simulation example based on the CarSim software.
Auteurs: Balázs Németh;Péter Gáspár;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1154 - 1164
Editeur: IEEE
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» The Resistive-Wall Instability in Multipulse Linear Induction Accelerators
Résumé:
The resistive-wall instability results from the Lorentz force on the beam due to the beam image charge and current. If the beam pipe is perfectly conducting, the electric force due to the image charge attracts the beam to the pipe wall, and the magnetic force due to the image current repels the beam from the wall. For a relativistic beam, these forces almost cancel, leaving a slight attractive force, which is easily overcome by external magnetic focusing. However, if the beam pipe is not perfectly conducting, the magnetic field due to the image current decays on a magnetic-diffusion time scale. If the beam pulse is longer than the magnetic diffusion time, the repulsion of the beam tail will be weaker than the repulsion of the beam head. In the absence of an external focusing force, this causes a head-to-tail sweep of the beam toward the wall. This instability is usually thought to be a concern only for long-pulse relativistic electron beams. However, with the advent of multipulse, high current linear induction accelerators, the possibility of pulse-to-pulse coupling of this instability should be investigated. We have explored pulse-to-pulse coupling using the linear accelerator model for Dual Axis Radiography for Hydrodynamic Testing beam dynamics code, and we present the results of this paper.
Auteurs: Carl Ekdahl;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 811 - 818
Editeur: IEEE
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» The SARFID Technique for Discriminating Tagged Items Moving Through a UHF-RFID Gate
Résumé:
The discrimination of tagged items moving along a conveyor belt from other tagged items that are present in the scenario is investigated, when a UHF-RFID gate is installed at a conveyor section. Indeed, tagged items that are static or randomly moving in the scenario (nomad tags) around the reader antenna could be detected even if they are not on the conveyor (false positive readings). The classification procedure here proposed exploits the SARFID phase-based technique used to localize tags on a conveyor belt, which takes advantage of the fact that the tagged items move along a conveyor, whose path and instantaneous speed are both known. The latter can be implemented with only a firmware upgrade, in any conveyor belt scenario already equipped with an RFID system, without any modification of the system infrastructure and additional (reference tags/multiple antennas) or ad hoc hardware. From experimental results in a real scenario, the discrimination between moving tags from static/nomad tags can be obtained with an overall accuracy greater than 99.9%, by employing only one reader antenna.
Auteurs: Alice Buffi;Paolo Nepa;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2863 - 2870
Editeur: IEEE
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» The SSSA-MyHand: A Dexterous Lightweight Myoelectric Hand Prosthesis
Résumé:
The replacement of a missing hand by a prosthesis is one of the most fascinating challenges in rehabilitation engineering. State of art prostheses are curtailed by the physical features of the hand, like poor functionality and excessive weight. Here we present a new multi-grasp hand aimed at overcoming such limitations. The SSSA-MyHand builds around a novel transmission mechanism that implements a semi-independent actuation of the abduction/adduction of the thumb and of the flexion/extension of the index, by means of a single actuator. Thus, with only three electric motors the hand is capable to perform most of the grasps and gestures useful in activities of daily living, akin commercial prostheses with up to six actuators, albeit it is as lightweight as conventional 1-Degrees of Freedom prostheses. The hand integrates position and force sensors and an embedded controller that implements automatic grasps and allows inter-operability with different human-machine interfaces. We present the requirements, the design rationale of the first prototype and the evaluation of its performance. The weight (478 g), force (31 N maximum force at the thumb fingertip) and speed of the hand (closing time: <370 ms), make this new design an interesting alternative to clinically available multi-grasp prostheses.
Auteurs: Marco Controzzi;Francesco Clemente;Diego Barone;Alessio Ghionzoli;Christian Cipriani;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 05.-2017, volume: 25, issue:5, pages: 459 - 468
Editeur: IEEE
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» The Top Eight Misconceptions about NP-Hardness
Résumé:
References to NP-completeness and NP-hardness are common in the computer science literature, but unfortunately they are often in error or misguided. This article explains the most widespread misconceptions, why they are wrong, and why we should care.
Auteurs: Zoltán Ádám Mann;
Apparue dans: Computer
Date publication: 05.-2017, volume: 50, issue:5, pages: 72 - 79
Editeur: IEEE
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» The Unicorn Runtime: Efficient Distributed Shared Memory Programming for Hybrid CPU-GPU Clusters
Résumé:
Programming hybrid CPU-GPU clusters is hard. This paper addresses this difficulty and presents the design and runtime implementation of Unicorn—a parallel programming model for hybrid CPU-GPU clusters. In particular, this paper proves that efficient distributed shared memory style programing is possible and its simplicity can be retained across CPUs and GPUs in a cluster, minus the frustration of dealing with race conditions. Further, this can be done with a unified abstraction, avoiding much of the complication of dealing with hybrid architectures. This is achieved with the help of transactional semantics (on shared global address spaces), deferred bulk data synchronization, workload pipelining and various communication and computation scheduling optimizations. We describe the said abstraction, our computation and communication scheduling system and report its performance on a few benchmarks like Matrix Multiplication, LU Decomposition and 2D FFT. We find that parallelization of coarse-grained applications like matrix multiplication or 2D FFT using our system requires only about 30 lines of C code to set up the runtime. The rest of the application code is regular single CPU/GPU implementation. This indicates the ease of extending parallel code to a distributed environment. The execution is efficient as well. When multiplying two square matrices of size $65,536times 65,536$ , Unicornachieves a peak performance of 7.88 TFlop/s when run over a cluster of 14 nodes with each node equipped with two Tesla M2070 GPUs and two 6-core Intel Xeon 2.67 GHz CPUs, connected over a 32 Gbps Infiniband network. In this paper, we also demonstrate that the Unicorn programming model can b- efficiently used to implement high level abstractions like MapReduce. We use such an extension to implement PageRank and report its performance. For a sample web of 500 million web pages, our implementation completes a page rank iteration in about 18 seconds (on average) on a 14-node cluster.
Auteurs: Tarun Beri;Sorav Bansal;Subodh Kumar;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1518 - 1534
Editeur: IEEE
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» The VLSI Architecture of a Highly Efficient Deblocking Filter for HEVC Systems
Résumé:
This paper presents the VLSI architecture and hardware implementation of a highly efficient deblocking filter (DBF) for High Efficiency Video Coding systems. In order to reduce the number of data accesses and thus to enhance the timing efficiency, novel data structures and memory access schemes for image pixels are proposed. Furthermore, a novel edge-fetching order is presented to strike a balance between the processing throughput and complexity. Based on the proposed structure and access pattern, a six-stage pipelined two-line DBF engine with low-latency data access sequence is designed, aiming to achieve high processing throughput while at the same time maintaining low complexity. The detailed storage structure and data access scheme are illustrated and VLSI architecture for the DBF engine is depicted in this paper. In addition, the proposed DBF is implemented using TSMC 90-nm standard cell library. The experimental results based on postlayout estimations show that the proposed design can achieve 60 frames/s for a frame resolution of $4096times 2048$ pixels (ultra high definition resolution) assuming an operating frequency of 100 MHz. Moreover, this design occupies an area complexity of 466.5 kGE with a power consumption of 26.26 mW. In comparison with prior designs targeting similar system specification and throughput, the proposed design results in a significantly reduced area complexity.
Auteurs: Po-Kai Hsu;Chung-An Shen;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 05.-2017, volume: 27, issue:5, pages: 1091 - 1103
Editeur: IEEE
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» Theoretical Characterization of X-Band Multiincidence Angle and Multipolarimetric SAR Data From Rice Paddies at Late Vegetative Stage
Résumé:
Various polarimetric decomposition techniques have been proposed and demonstrated for more than 20 years. However, they still have never been operational applications because of insufficient validations. The true composition ratio of scattering mechanisms within a radar backscatter has to be known. To achieve this, a novel comprehensive approach to accurately identify the contribution of each scattering mechanism by a multiincidence angle and multipolarimetric (MIMP) synthetic aperture radar (SAR) observation combined with a theoretical model simulation is introduced. Rice paddies in Niigata City in Japan having a simple vegetation structure without topography were observed by X-band polarimetric and interferometric SAR 2 (Pi-SAR2), by gradually varying the flight path in terms of incidence angle. In addition to the MIMP SAR observation, a dominant scattering mechanism is reliably isolated through the theoretical characterization of the data by a discrete scatterer model. In the case of the rice paddies at a late vegetative stage, a dominant scattering on HH gradually varies from the double-bounce scattering to the volume scattering of rice grains in terms of incidence angle, whereas VV is affected by various volume scatterings of grains, leaves, and stems at the small, medium, and large incidence angles, respectively. HV is simply affected by the volume scattering of grains at the small incidence angle, and then it gradually switches to the volume scattering of the stalks. This brand new approach by the MIMP SAR observation with the theoretical modeling for this specific stage could take forward the polarimetric decomposition studies.
Auteurs: Motofumi Arii;Hiroyoshi Yamada;Tatsuharu Kobayashi;Shoichiro Kojima;Toshihiko Umehara;Tomomi Komatsu;Takeshi Nishimura;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2706 - 2715
Editeur: IEEE
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» Theory of Impedance Loaded Loop Antennas and Nanorings From RF to Optical Wavelengths
Résumé:
The analytical theory of perfectly conducting thin-wire closed-loop antennas with multiple loads in the periphery was formally derived in the 1950s and 1960s. In this paper, it is extended to loop antennas and nanorings for use in communications, in the “Internet of things,” and as metamaterials. The new derivation relies on recent work from 2013 that incorporates the surface impedance of metal wires into the standard theory, thus pushing its applicability into the gigahertz, terahertz, and optical regimes. Surface impedance effects cause losses and phase shifts in the current within the loop, which in turn cause wavelength scaling and degradation of signal strength. These effects are modeled using a critical point transition model of permittivity and of the index of refraction. The new results therefore extend standard loop antenna theory so that it now includes characteristics of multiply loaded loops over a very broad spectrum from radio frequencies to the optical region. The new model is verified using modern simulation tools. The examples given here include resistive and capacitive loading.
Auteurs: Arnold F. McKinley;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2276 - 2281
Editeur: IEEE
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» Thin-Film Transistors With Amorphous Indium–Gallium-Oxide Bilayer Channel
Résumé:
The authors report the deposition of amorphous indium–gallium-oxide (a-IGO) films on glass substrate by co-sputtering and the fabrication of thin film transistors (TFTs) with a-IGO bilayer channel. It was found that the electron mobility, $mu _text{FE}$ , sub-threshold swing, SS, and $text{I}_{text {on}}/text{I}_{text {off}}$ ratio of the fabricated TFTs were all better than those reported previously from the TFTs with single a-IGO channel. By properly controlling the sputtering powers, we achieved TFTs with $mu _{text {FE}}$ of 53.2 cm 2/Vs, SS of 0.19 V/decade and $text{I}_{text {on}}/text{I}_{text {off}}$ ratio of ~107.
Auteurs: C. P. Yang;S. J. Chang;T. H. Chang;C. Y. Wei;Y. M. Juan;C. J. Chiu;W. Y. Weng;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 572 - 575
Editeur: IEEE
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» Three-Dimensional Cross-Coupled Silicon Nitride Racetrack Resonator-Based Tunable Optical Filter
Résumé:
A tunable three-dimensional silicon nitride racetrack resonator was experimentally demonstrated, with a microring resonator on a bottom layer and a feedback cross-coupled waveguide on a top layer. At a 1559.3-nm wavelength, an extinction ratio of more than 14 dB and free spectral range of 2.7 nm can be realized with a quality factor of about $1.88times 10^{4}$ . The filter performance, such as the resonance wavelength and extinction ratio, can be thermo-optically tuned based on the electrical control of a heater above the feedback waveguide. The presented device has a potential to be applied as a tunable modulator/switch as well as a highly sensitive sensor.
Auteurs: Jijun Feng;Ryoichi Akimoto;Qiang Hao;Heping Zeng;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 771 - 774
Editeur: IEEE
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» Three-Dimensional Interfacial Stress Decoupling Method for Rehabilitation Therapy Robot
Résumé:
Robot-assisted therapy can provide effective rehabilitation training for stroke patients. The interfacial stress between the manipulator and the grasped patient's body is very important for a rehabilitation therapy robot. This paper presents a measurement method, which is able to decouple the measurement of the three-dimensional (3-D) interfacial stress components. To implement the method, interfacial stress sensors were fabricated based on plate capacitance and a superelastic material, while a high-resolution microcapacitance measurement circuit was developed based on a minimal system microprocessor and a programmable controller, and experiments are carried out by using a 3-D stress simulation equipment. The results show that the measurement circuit is capable of measuring a range of 1 fF–30 pF capacitance with a resolution better than 1 fF, and the sensor is capable of measuring Z-direction normal compressive stress at a range of ${text{0-3.0}} text{kgf}/text{cm}^2$ with a sensitivity of ${text{101}} text{fF}/text{kgf}/text{cm}^2$ and X - and Y-direction shear stress at a range of $0-1.0 text{kgf}/text{cm}^2$ with a sensitivity of ${text{118}} text{fF}/text{kgf}/text{cm}^2$. This method can be applied to rehabilitation therapy robots to decouple the measurement of the 3-D interfacial stress components.
Auteurs: Xiaozhou Lü;Weimin Bao;Songlin Wang;Yebo Tao;Jiayi Yang;La Jiang;Jianan Jiang;Xi Li;Xi Xie;Renjie Chen;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3970 - 3977
Editeur: IEEE
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» Three-Port Frequency-Selective Absorptive Limiter
Résumé:
This letter describes a novel three-port absorptive limiter for frequency-selective circuits based on a configuration similar to a conventional 90° hybrid coupler. This circuit uses the switching behavior of common diodes to change between the nonlimiting and absorptive limiting states. Theoretical descriptions and designs are presented along with prototypes based on PIN diodes. Measurements of the limiting performance of the devices at approximately 2 GHz as a function of power demonstrate the viability of the concept.
Auteurs: Alberto Hueltes;Eduard Rocas;Carlos Collado;Jordi Mateu;Nathan Orloff;James C. Booth;David Garcia-Pastor;Rafael Perea-Robles;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 479 - 481
Editeur: IEEE
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» Tiling the Bunny: Quad Layouts for Efficient 3D Geometry Representation
Résumé:
Ultimately, any information to be processed by computers must be represented as a plain sequence of numbers. This poses a major challenge when representing complex 3D shapes. Marcel Campen's research explores how to efficiently identify a good quad layout (a partition of a surface into simple four-sided pieces). This article shows how novel algorithmic ideas can be combined to form both automatic and interactive quad-layout generation pipelines.
Auteurs: Marcel Campen;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 88 - 95
Editeur: IEEE
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» Time Domain Audio Features for Chainsaw Noise Detection Using WSNs
Résumé:
In this paper, we present an analysis of low complexity signal processing algorithms capable of identifying special noises, such as the sounds of forest machinery (used for forestry, logging). Our objective is to find methods that are able to detect internal combustion engines in rural environment, and are also easy to implement on low power devices of WSNs (wireless sensor networks). In this context, we review different methods for detecting illegal logging, with an emphasis on autocorrelation and TESPAR audio techniques. The processing of extracted audio features is to be solved with limited memory and processor resources typical for low cost sensors modes. The representation of noise models is also considered with different archetypes. Implementations of the proposed methods were tested not by simulations but on sensor nodes equipped with an omnidirectional microphone and a low power microcontroller. Our results show that high recognition rate can be achieved using time domain algorithms and highly energy efficient and inexpensive architectures.
Auteurs: László Czúni;Péter Zoltán Varga;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2917 - 2924
Editeur: IEEE
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» Time Series Modeling for Dynamic Thermal Rating of Overhead Lines
Résumé:
Dynamic thermal rating (DTR) is more accurate and can better utilize the transmission/distribution capacity of an electric power system compared to static thermal rating. It is beneficial to integrate DTR into power system planning problems where modeling the DTR is vital. This paper presents a new modeling method for DTR that consists of three sequential steps: A multivariate polynomial regression between the DTR and its four affecting factors, an hourly normalization, and an autoregressive integrated moving average (ARIMA). Three types of polynomial regressions were developed based on the analysis of the heat balance model for calculation of the DTR. For the purpose of comparison, several other modeling methods for the DTR were designed based on a widely used wind speed modeling method. The performance of the different modeling methods was verified using case studies from Austin, USA and Wawa, Canada. The results show that the model of the DTR obtained using the proposed method is superior in terms of both probability distribution and fitting accuracy.
Auteurs: Junpeng Zhan;C. Y. Chung;Elemer Demeter;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2172 - 2182
Editeur: IEEE
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» Time-Encoded Values for Highly Efficient Stochastic Circuits
Résumé:
Stochastic computing (SC) is a promising technique for applications that require low area overhead and fault tolerance, but can tolerate relatively high latency. In the SC paradigm, logical computation is performed on randomized bit streams. In prior work, streams were generated with linear feedback shift registers; these contributed heavily to the hardware cost and consumed a significant amount of power. This paper introduces a new approach for encoding signal values: computation is performed on analog periodic pulse signals. Exploiting pulse width modulation, time-encoded signals corresponding to specific values are generated by adjusting the frequency and duty cycles of pulse width modulated (PWM) signals. With this approach, the latency, area, and energy consumption are all greatly reduced. Experimental results on image processing applications show up to 99% performance speedup, 98% saving in energy dissipation, and 40% area reduction compared to prior stochastic approaches. Circuits synthesized with the proposed approach can work as fast and energy-efficiently as a conventional binary design while retaining the fault-tolerance and low-cost advantages of conventional stochastic designs.
Auteurs: M. Hassan Najafi;Shiva Jamali-Zavareh;David J. Lilja;Marc D. Riedel;Kia Bazargan;Ramesh Harjani;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1644 - 1657
Editeur: IEEE
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» Time-Resolving Characteristics of Pixel- and Charge-Division-Type Position-Sensitive SiPMs With Epitaxial Quenching Resistors
Résumé:
Silicon photomultipliers (SiPMs) with epitaxial quenching resistors (EQR SiPMs) are easier to fabricate with small microcells that provide a large fill factor and an adequate dynamic range. They are suitable for use as pixel-type and charge-division-type position-sensitive (PS) devices. In this paper, an EQR SiPM line array, with 0.12 $times $ 0.12 mm2 active area and 120 microcells in one element, provided a single-photon time resolution (SPTR) of 36.9 ± 1.0 ps full-width at half-maximum. A tetra-lateral charge-division-type PS-SiPM demonstrated a lateral transmission time delay of 0.7 ps/ $mu text{m}$ . This linearity between the lateral transmission time delay and the relative distance from the light spot position to the opposite anodes may be used to quantify the position resolution for this type of PS-SiPM. The limiting factors which affect the time-resolving characteristics of EQR SiPM, such as electronic noise and lateral transmission time delay, were also discussed.
Auteurs: Baicheng Li;Shenyuan Wang;Chenhui Li;Tianqi Zhao;Quanlong Miao;Ruiheng Wang;Jianquan Jia;Kun Liang;Ru Yang;Dejun Han;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2239 - 2243
Editeur: IEEE
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» Top Downloads in IEEE Xplore [Reader's Choice]
Résumé:
Provides a listing of the editorial board, current staff, committee members and society officers.
Auteurs: Chungshui Zhang;
Apparue dans: IEEE Signal Processing Magazine
Date publication: 05.-2017, volume: 34, issue:3, pages: 6 - 7
Editeur: IEEE
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» Top-Gate Electric-Double-Layer IZO-Based Synaptic Transistors for Neuron Networks
Résumé:
In this letter, top-gate electric-double- layer (EDL) indium–zinc-oxide (IZO)-based synaptic transistors were demonstrated. A silicon oxide solid electrolyte film was used as the insulator, which was deposited by the plasma-enhanced chemical vapor deposition method at room temperature. A low operation voltage of 1 V was achieved due to the formation of the EDL layer at the SiO2/IZO interface. In the top-gate synaptic transistors, paired-pulse facilitation and high-frequency filter were mimicked, which are the short-term synaptic behaviors. Standard microfabrication processes were used to pattern, which could be used for large integration in the future.
Auteurs: Jiabin Wang;Yuxing Li;Yi Yang;Tian-Ling Ren;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 588 - 591
Editeur: IEEE
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» Toward a Flexible, Scalable, and Transparent Thin-Film Camera
Résumé:
This paper summarizes our progress toward a first fully transparent, flexible, and scalable thin-film image sensor and reviews lensless imaging approaches. Combining sensing and imaging in multiple layers has the potential to enable entire thin-film camera systems that make the capturing of images, light fields, and depth information possible.
Auteurs: Oliver Bimber;Alexander Koppelhuber;
Apparue dans: Proceedings of the IEEE
Date publication: 05.-2017, volume: 105, issue:5, pages: 960 - 969
Editeur: IEEE
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» Toward Local Stability Analysis of Externally Interfered Digital Filters Under Overflow Nonlinearity
Résumé:
This brief focuses on the local stability analysis of 1-D digital filters that are subject to the saturation overflow nonlinearity and external interference by exploiting local saturation arithmetic. A novel stability criterion that analyzes the local asymptotic stability of a digital filter under zero external interference is investigated. Furthermore, an extension to attain a local ${H}_{infty}$ performance is developed to tackle the external interference. The conventional global stability criteria using the global saturation arithmetic can be derived as specific cases of the proposed local results. The proposed local stability criteria provide a lesser conservative estimate of interference attenuation level in comparison with existing global techniques. Furthermore, information on the tolerable energy bound on external interference for a given attenuation level is also revealed contrary to global schemes. In addition to this, the proposed methodology can be applied to evaluate the minimum word length to achieve the desired fixed-point resolution and the performance specifications for the sake of hardware optimization. A novel two-step approach is also provided for solving the filter stability analysis condition using convex routines. A numerical example is presented to demonstrate these features.
Auteurs: Irza Arif;Muhammad Rehan;Muhammad Tufail;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 595 - 599
Editeur: IEEE
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» Toward Mitigating Phantom Jam Using Vehicle-to-Vehicle Communication
Résumé:
Traffic jams often occur without any obvious reasons such as traffic accidents, roadwork, or closed lanes. Under moderate to high traffic density, minor perturbations to traffic flow (e.g., a strong braking motion) are easily amplified into a wave of stop-and-go traffic. This is known as a phantom jam. In this paper, we aim to mitigate phantom jams leveraging the three-phase traffic theory and vehicle-to-vehicle (V2V) communication. More specifically, an efficient phantom jam control protocol is proposed in which a fuzzy inference system is integrated with a V2V-based phantom jam detection algorithm to effectively capture the dynamics of traffic jams. Per-lane speed difference under traffic congestion is taken into account in the protocol design, so that a phantom jam is controlled separately for each lane, improving the performance of the proposed protocol. We implemented the protocol in the Jist/SWAN traffic simulator. Simulations with artificially generated traffic data and real-world traffic data collected from vehicle loop detectors on Interstate 880, California, USA, demonstrate that our approach has by up to 9% and 4.9% smaller average travel times (at penetration rates of 10%) compared with a state-of-the-art approach, respectively.
Auteurs: Myounggyu Won;Taejoon Park;Sang H. Son;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1313 - 1324
Editeur: IEEE
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» Toward Modeling the Intrinsic Complexity of Test Problems
Résumé:
The concept of intrinsic complexity explains why different problems of the same type, tackled by the same problem solver, can require different times to solve and yield solutions of different quality. This paper proposes a general four-step approach that can be used to establish a model for the intrinsic complexity of a problem class in terms of solving time. Such a model allows prediction of the time to solve new problems in the same class and helps instructors develop more reliable test problems. A complexity model, furthermore, enhances understanding of the problem and can point to new aspects interesting for education and research. Students can use complexity models to assess and improve their learning level. The approach is explained using the K-map minimization problem as a case study. The implications of this research for other problems in electrical and computer engineering education are highlighted. An important aim of this paper is to stimulate future research in this area. An ideal outcome of such research is to provide complexity models for many, or even all, relevant problem classes in various electrical and computer engineering courses.
Auteurs: Abdulhadi Shoufan;
Apparue dans: IEEE Transactions on Education
Date publication: 05.-2017, volume: 60, issue:2, pages: 157 - 163
Editeur: IEEE
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» Toward Robust Segmentation Results Based on Fusion Methods for Very High Resolution Optical Image and LiDAR Data
Résumé:
Using very high resolution remote sensing images to extracting urban features from very high resolution remote sensing images is a very complex and difficult task. The improvement in geospatial technologies brought forward many solutions that can help in improving the process of urban feature extraction. Data collection using light detection and ranging (LiDAR) and capturing very high resolution optical images concurrently is one of these solutions. This research proves that the fusion of high-resolution optical image with LiDAR data can improve image processing results. It is based on increasing urban features extraction success rate by reducing oversegmentation. The fusion process relies first on wavelet transform techniques, which are run several times with different parameters (rules). Then, an innovative technique is implemented to improve fusion process. The two techniques are compared, and both have reduced fragmented segments and created homogeneous urban features. However, the fused image with the innovative technique has improved the accuracy of the segmentation results. The average accuracy for building detection is 96% (maximum 100% and minimum 92%) using the innovative technique compared to 21% and 51% for no fusion and wavelet-fusion-based techniques. Furthermore, an index is used to measure the quality of the building details which are detected after using the innovative fusion technique. The result indicates that the quality index is greater or equal to 86%.
Auteurs: Mohamad M. Awad;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 2067 - 2076
Editeur: IEEE
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» Towards a Reliable Detection of Covert Timing Channels over Real-Time Network Traffic
Résumé:
Inter-packet delays (IPD) of legitimate network traffic can be exploited for information hiding purposes and distribution of secret and sensitive data. This process is known as Covert Timing Channel (CTC), which is usually used for malicious purposes. In this paper we propose a novel approach, CTC Real-Time Detection (CTCRTD) to detect such activities based on IPD distributions of network traffic. We present and leverage three different non-parametric statistical tests that can be used to generate distinct statistical test scores for overt and covert traffic IPDs. Our new detection approach is designed around two major benefits: First, the new detection approach can detect various CTC algorithms that have similar impact on network traffic IPD distributions. Second, our detection approach reliably detects covert communication over real-time network traffic with minimal lag between the start of covert activity and the point of detection. We have evaluated and verified the reliability and effectiveness of our detection approach utilizing a large number of overt and covert traffic streams and various scenarios of the proposed detection technique. The obtained results show that the new detection approach can precisely differentiate between overt and covert network traffic and detect covert communication activities over 90 percent of time on average.
Auteurs: Fahimeh Rezaei;Michael Hempel;Hamid Sharif;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 05.-2017, volume: 14, issue:3, pages: 249 - 264
Editeur: IEEE
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» Tracking With Sparse and Correlated Measurements via a Shrinkage-Based Particle Filter
Résumé:
This paper presents a shrinkage-based particle filter method for tracking a mobile user in wireless networks. The proposed method estimates the shadowing noise covariance matrix using the shrinkage technique. The particle filter is designed with the estimated covariance matrix to improve the tracking performance. The shrinkage-based particle filter can be applied in a number of applications for navigation, tracking, and localization when the available sensor measurements are correlated and sparse. The performance of the shrinkage-based particle filter is compared with the posterior Cramer–Rao lower bound, which is also derived in this paper. The advantages of the proposed shrinkage-based particle filter approach are demonstrated via simulation and experimental results.
Auteurs: Aroland Kiring;Naveed Salman;Chao Liu;Iñaki Esnaola;Lyudmila Mihaylova;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3152 - 3164
Editeur: IEEE
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» Transductive Video Segmentation on Tree-Structured Model
Résumé:
This paper presents a transductive multicomponent video segmentation algorithm, which is capable of segmenting the predefined object of interest in the frames of a video sequence. To ensure temporal consistency, a temporal coherent parametric min-cut algorithm is developed to generate segmentation hypotheses based on visual cues and motion cues. Furthermore, each hypothesis is evaluated by an energy function from foreground resemblance, foreground/background divergence, boundary strength, and visual saliency. In particular, the state-of-the-art R-convolutional neural network descriptor is leveraged to encode the visual appearance of the foreground object. Finally, the optimal segmentation of the frame can be attained by assembling the segmentation hypotheses through the Monte Carlo approximation. In particular, multiple foreground components are built to capture the variances of the foreground object in shapes and poses. To group the frames into different components, a tree-structured graphical model named temporal tree is designed, where visually similar and temporally coherent frames are arranged in branches. The temporal tree can be constructed by iteratively adding frames to the active nodes by probabilistic clustering. In addition, each component, consisting of frames in the same branch, is characterized by a support vector machine classifier, which is learned in a transductive fashion by jointly maximizing the margin over the labeled frames and the unlabeled frames. As the frames from the same video sequence follow the same distribution, the transductive classifiers achieve stronger generalization capability than inductive ones. Experimental results on the public benchmarks demonstrate the effectiveness of the proposed method in comparison with other state-of-the-art supervised and unsupervised video segmentation methods.
Auteurs: Botao Wang;Zhihui Fu;Hongkai Xiong;Yuan F. Zheng;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 05.-2017, volume: 27, issue:5, pages: 992 - 1005
Editeur: IEEE
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» Transferred Deep Learning for Anomaly Detection in Hyperspectral Imagery
Résumé:
In this letter, a novel anomaly detection framework with transferred deep convolutional neural network (CNN) is proposed. The framework is designed by considering the following facts: 1) a reference data with labeled samples are utilized, because no prior information is available about the image scene for anomaly detection and 2) pixel pairs are generated to enlarge the sample size, since the advantage of CNN can be realized only if the number of training samples is sufficient. A multilayer CNN is trained by using difference between pixel pairs generated from the reference image scene. Then, for each pixel in the image for anomaly detection, difference between pixel pairs, constructed by combining the center pixel and its surrounding pixels, is classified by the trained CNN with the result of similarity measurement. The detection output is simply generated by averaging these similarity scores. Experimental performance demonstrates that the proposed algorithm outperforms the classic Reed-Xiaoli and the state-of-the-art representation-based detectors, such as sparse representation-based detector (SRD) and collaborative representation-based detector.
Auteurs: Wei Li;Guodong Wu;Qian Du;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 597 - 601
Editeur: IEEE
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» Transformer-Feedback Dual-Band Neutralization Technique
Résumé:
A dual-band neutralization technique based on the transformer feedback between the drain and the gate of a transistor is presented. The drain and gate bias lines of the transistor are realized as multiorder $LC$ networks. Transformer coupling between the inductors of the two networks can be used to concurrently neutralize the gate–drain capacitance of the transistor at multiple frequencies. Moreover, these frequencies can be placed close together to achieve wideband neutralization. A proof-of-concept dual-band 27/33-GHz amplifier is designed and implemented in a 0.1-$mutext{m}$ GaAs pseudomorphic high-electron mobility transistor process. The maximum gain of the transistor at the two frequency bands is improved by more than 6 dB using the neutralization technique. The amplifier exhibits a gain of 16/15 dB and a reverse isolation of 60/50 dB at the lower/upper frequency band. It consumes 24 mA from a 1-V supply.
Auteurs: Gholamreza Nikandish;Ali Medi;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 495 - 499
Editeur: IEEE
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» Transmission Constrained UC With Wind Power: An All-Scenario-Feasible MILP Formulation With Strong Nonanticipativity
Résumé:
To deal with the difficulties caused by uncertainty of renewable energy sources in solving transmission constrained unit commitment (TCUC), robust optimization (RO) and scenario-based stochastic optimization (SO) methods have gained popularity in recent years. However, RO formulations have a multilevel (min-max-min or min-max) structure and the solution methods are usually complicated. On the other hand, when SO-based formulation is adopted, a careful balance is often required between accuracy and scale of the formulation, since they are conflicting with each other when determining the number of scenarios. Moreover, nonanticipative constraints on economic dispatch (ED) decisions are sometimes not considered in two-stage stochastic UC formulation. An example is given in this paper to show that this may have a serious consequence. The motivation of this paper is to establish a TCUC formulation that can address the above concerns. In summary, the proposed formulation has three features including: it is single-level rather than multilevel, it is established based on very limited scenarios while the solution is feasible to all scenarios, and finally, nonanticipativity of both UC and ED decisions is guaranteed by the formulation. Numerical testing is also performed and the results show that the proposed formulation is effective.
Auteurs: Qiaozhu Zhai;Xuan Li;Xuejiao Lei;Xiaohong Guan;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1805 - 1817
Editeur: IEEE
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» Transmission System Geomagnetically Induced Current Model Validation
Résumé:
Geomagnetically induced currents (GICs) have the potential to severely disrupt power system operations by causing increased reactive power losses in the high-voltage transmission grid. This paper focuses on validating the model which relates the GICs to their deriving electric field. A novel validation framework is proposed with the advantage of considering the system uncertainties and network information availability. The effectiveness of this approaches is validated using both a 20 bus test system as well as actual GIC data provided by American Transmission Company.
Auteurs: Maryam Kazerooni;Hao Zhu;Thomas J. Overbye;David A. Wojtczak;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2183 - 2192
Editeur: IEEE
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» Trending Paths: A New Semantic-Level Metric for Comparing Simulated and Real Crowd Data
Résumé:
We propose a new semantic-level crowd evaluation metric in this paper. Crowd simulation has been an active and important area for several decades. However, only recently has there been an increased focus on evaluating the fidelity of the results with respect to real-world situations. The focus to date has been on analyzing the properties of low-level features such as pedestrian trajectories, or global features such as crowd densities. We propose the first approach based on finding semantic information represented by latent Path Patterns in both real and simulated data in order to analyze and compare them. Unsupervised clustering by non-parametric Bayesian inference is used to learn the patterns, which themselves provide a rich visualization of the crowd behavior. To this end, we present a new Stochastic Variational Dual Hierarchical Dirichlet Process ( SV-DHDP) model. The fidelity of the patterns is computed with respect to a reference, thus allowing the outputs of different algorithms to be compared with each other and/or with real data accordingly. Detailed evaluations and comparisons with existing metrics show that our method is a good alternative for comparing crowd data at a different level and also works with more types of data, holds fewer assumptions and is more robust to noise.
Auteurs: He Wang;Jan Ondřej;Carol O’Sullivan;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1454 - 1464
Editeur: IEEE
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» TRO: An On-Chip Ring Oscillator-Based GHz Transient IR-Drop Monitor
Résumé:
With silicon technology further scaling, the switching activity is getting more intense in modern designs. The large switching activities together with GHz operation frequency can greatly affect the power integrity by generating IR-drop noises. Excessive IR-drop can cause functional failures such as timing failure, abnormal reset and SRAM flipping. Hence, IR-drop needs to be monitored in-field. However, directly measuring transient IR-drop waveform usually involves high design or equipment cost. This paper presents a low-cost on-chip GHz ring oscillator-based transient IR-drop monitor (TRO). TRO is composed of all-digital elements, and can be easily integrated into existing IC design flow with negligible overhead. Different from traditional transient IR-drop monitors, TRO measures IR-drop waveform width and average in-field, while recovers IR-drop peak, and reconstructs the transient noise waveform during data analysis or customer return, which eliminates the need for custom circuits or high frequency sampling clock. Simulation results show that TRO is sensitive to IR-drop with peak and width larger than 100 mV and 1.0 ns, which is suitable for GHz IC monitoring. The IR-drop noise width detection resolution can reach 0.125 ns and higher under the help of the proposed edge detector, with noise peak and width measurement error rate less than 6.8% and 9.0%, for 97% of the Monte Carlo samples considering process variations. According to the results and analyses, TRO is also able to trigger quick adaptation within one clock cycle.
Auteurs: Xiaoxiao Wang;Pengyuan Jiao;Mehdi Sadi;Donglin Su;LeRoy Winemberg;Mark Tehranipoor;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 855 - 868
Editeur: IEEE
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» Trump's plans could scuttle new Hybrid Car Tech in U.S. [News]
Résumé:
Global policy efforts to boost fuel economy are progressively electrifying the automobile and expanding technology options to cut greenhouse gas emissions. One of the most exciting recent developments is, however, at risk of failure in the United States: a new generation of "mild hybrid" technology that could be undercut by President Donald Trump's attempts to stall U.S. climate policy.
Auteurs: Peter Fairley;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 12 - 13
Editeur: IEEE
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» Trusting Machines and Gender Diversity [President's Message]
Résumé:
Presents the President's message for this issue of the publication.
Auteurs: Pablo A. Estevez;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 05.-2017, volume: 12, issue:2, pages: 3 - 17
Editeur: IEEE
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» Truth-Telling Mechanism for Two-Way Relay Selection for Secrecy Communications With Energy-Harvesting Revenue
Résumé:
This paper brings the novel idea of paying the utility to the winning agents in terms of some physical entity in cooperative communications. Our setting is a secret two-way communication channel where two transmitters exchange information in the presence of an eavesdropper. The relays are selected from a set of interested parties, such that the secrecy sum rate is maximized. In return, the selected relay nodes’ energy harvesting requirements will be fulfilled up to a certain threshold through their own payoff so that they have the natural incentive to be selected and involved in the communication. However, relays may exaggerate their private information in order to improve their chance to be selected. Our objective is to develop a mechanism for relay selection that enforces them to reveal the truth since otherwise they may be penalized. We also propose a joint cooperative relay beamforming and transmit power optimization scheme based on an alternating optimization approach. Note that the problem is highly non-convex, since the objective function appears as a product of three correlated Rayleigh quotients. While a common practice in the existing literature is to optimize the relay beamforming vector for given transmit power via rank relaxation, we propose a second-order cone programming-based approach in this paper, which requires a significantly lower computational task. The performance of the incentive control mechanism and the optimization algorithm has been evaluated through numerical simulations.
Auteurs: Muhammad R. A. Khandaker;Kai-Kit Wong;Gan Zheng;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3111 - 3123
Editeur: IEEE
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» Turbine Stability-Constrained Available Wind Power of Variable Speed Wind Turbines for Active Power Control
Résumé:
The active power control (APC) of variable-speed wind turbines (VSWT) is increasingly required to support the power system operation and control. Besides control strategies, the power reference also exerts a significant influence upon APC performance. Due to the VSWT instability, the optimistic reference which is usually determined according to the conventional available wind power (AWP) based on maximum power point, cannot be sustainably maintained over the dispatch period. This may results in frequent interruption of power reference tracking. On the other hand, the conservative reference will easily lead to excessive pitch regulation. In this letter, the turbine stability-constrained available wind power is defined and analyzed to sustain the power generation of scheduled wind turbines at a maximum level. Simulation results show that the VSWT dispatched according to the proposed AWP can maintain stable power generation with less pitch action and therefore better support secure and economic power system operations.
Auteurs: Minghui Yin;Yan Xu;Chun Shen;Jiankun Liu;Zhao Yang Dong;Yun Zou;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2487 - 2488
Editeur: IEEE
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» Two mm-Wave VCOs in 28-nm UTBB FD-SOI CMOS
Résumé:
Two 60-GHz band voltage controlled oscillators (VCOs) designed in a 28-nm ultrathin body and buried oxide fully depleted silicon on insulator (UTBB FD-SOI) CMOS process are demonstrated and compared. Both VCOs have identical cross-coupled nMOS cores and dissipate 3.15 mW from a 0.9-V supply. The first design uses a standard FET current source and achieves a figure of merit (FOM) of −181 dBc/Hz, whereas the second employs a filtered current source and achieves a state-of-the-art FOM of −187 dBc/Hz. The achieved 6-dB improvement demonstrates the efficiency of the filtering technique at millimeter wave frequencies and the feasibility of efficient low-phase noise designs in 28-nm UTBB FD-SOI CMOS. The active area of the filtered VCO is $90,,mu text{m},,times 180,,mu text{m}$ and the standard VCO has an area of $80,,mu text{m},,times 110,,mu text{m}$ .
Auteurs: Therese Forsberg;Johan Wernehag;Anders Nejdel;Henrik Sjöland;Markus Törmänen;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 509 - 511
Editeur: IEEE
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» Two Successful 2016 IAS Conferences [Conference News]
Résumé:
Presents information on various IAS society 2016 conferences.
Auteurs: Allan Dukeshire;Ken McFarland;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 05.-2017, volume: 23, issue:3, pages: 75 - 76
Editeur: IEEE
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» Two-Extra-Column Trellis Min–Max Decoder Architecture for Nonbinary LDPC Codes
Résumé:
In this brief, a novel two-extra-column trellis min–max algorithm and the decoder architecture based on only the first minimum values are proposed for nonbinary low-density parity-check (NB-LDPC) codes. The algorithm greatly reduces the hardware complexity and improves the latency as well as the throughput of the proposed decoder architecture compared with the previous works. A layered decoder architecture based on the proposed algorithm for (837, 726) NB-LDPC code over GF(32) is implemented with a 90-nm CMOS technology. The results show a decrease in the area of 24.6% for the check node unit and 75.6% for the whole decoder with a throughput of 1.27 Gb/s. The proposed decoder provides a lower area and a higher efficiency compared with the state of the art of high-rate NB-LDPC codes with high Galois-field order.
Auteurs: Huyen Pham Thi;Hanho Lee;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1787 - 1791
Editeur: IEEE
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» Two-View 3D Reconstruction for Food Volume Estimation
Résumé:
The increasing prevalence of diet-related chronic diseases coupled with the ineffectiveness of traditional diet management methods have resulted in a need for novel tools to accurately and automatically assess meals. Recently, computer vision-based systems that use meal images to assess their content have been proposed. Food portion estimation is the most difficult task for individuals assessing their meals and it is also the least studied area. This paper proposes a three-stage system to calculate portion sizes using two images of a dish acquired by mobile devices. The first stage consists in understanding the configuration of the different views, after which a dense three-dimensional (3D) model is built from the two images; finally, this 3D model serves to extract the volume of the different items. The system was extensively tested on 77 real dishes of known volume, and achieved an average error of less than 10% in 5.5 seconds per dish. The proposed pipeline is computationally tractable and requires no user input, making it a viable option for fully automated dietary assessment.
Auteurs: Joachim Dehais;Marios Anthimopoulos;Sergey Shevchik;Stavroula Mougiakakou;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 05.-2017, volume: 19, issue:5, pages: 1090 - 1099
Editeur: IEEE
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» Ultracompact 160-GHz FMCW Radar MMIC With Fully Integrated Offset Synthesizer
Résumé:
The dynamic range of frequency modulated continuous wave (FMCW) radar sensors is often limited by the phase noise of the ramp signal. Especially at millimeter wave (mm-wave) frequencies, a low phase noise signal is very difficult to obtain. In this paper, a new system architecture, which is implemented in a low-cost, ultracompact FMCW radar monolithic microwave integrated circuit (MMIC) at 160 GHz, is proposed to address this topic. The approach is based on a frequency offset synthesizer, whose upconverting mixer is driven by a stabilized low phase noise local oscillator (LO) signal. This LO is generated by a fixed-frequency phase locked loop with a $2^{N}$ divider. The upconversion of the ramp signal with the stabilized LO signal leads to an excellent mm-wave phase noise of −89 dBc/Hz at a frequency offset of 1 MHz. By integrating the antennas on the MMIC, interconnects at mm-wave frequencies to package or printed circuit board are avoided and a simple assembly and interconnection technology is feasible. The ultracompact MMIC is realized on an area of only 2 mm2, including the integrated antennas. A precision below 5 $mu text{m}$ for range measurements is demonstrated with the radar sensor. Additionally, the radar performance is evaluated with two different voltage-controlled oscillators for the generation of the ramp signal.
Auteurs: Martin Hitzler;Stefan Saulig;Linus Boehm;Winfried Mayer;Wolfgang Winkler;Nasir Uddin;Christian Waldschmidt;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1682 - 1691
Editeur: IEEE
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» Ultrahigh Index and Low-loss Silicon Rich Nitride Thin film for NIR HAMR Optics
Résumé:
Ultrahigh index and low-loss silicon rich nitride (SiNx) thin-film material is developed and studied for application in heat-assisted magnetic recording (HAMR) as light delivery system operating in the near infrared (NIR) wavelength range. The film is deposited by low-temperature inductively coupled plasma chemical vapour deposition and developed through the tuning of SiH4/N2/Ar gases ratio. Film characterization of SiNx, including material composition, optical properties, and thermal-optics is presented. X-ray photoelectron spectroscopy shows the spectrum of binding energy and a material composition of $x = 0.6$ . The refractive index of developed film is >3.0 with an optical bandgap around 656 nm according to ellipsometery and photospectrometery measurement. Characterization of ultra-low optical absorption is addressed with the use of ellipsometry and prism coupler waveguide loss measurement and the developed film has an absorption coefficient of about 10−5 in the NIR. The thermal optic characterization shows a thermal optical coefficient of $2.66 times 10^{-4}~text{K}^{-1}$ with a stable optical absorption at temperature up to 200 °C. The use of the developed SiNx film for HAMR as high-index contrast nanowaveguide and enabling to integrate III–V semiconductor laser for a fully integrated light delivery system is discussed.
Auteurs: Kim Peng Lim;Vivek Krishnamurthy;Ji Feng Ying;Jing Pu;Qian Wang;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 7
Editeur: IEEE
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» Ultrawideband In-Ground Multiport Antenna for Small Cell Applications
Résumé:
In this paper, a four-port ultrawideband antenna design is proposed. The antenna is suitable for installation in pavements. The main application of this antenna is in the reuse of the existing manholes for radio equipment and antenna installation. Equally important is its application in dense network deployment as a result of its capability to alleviate intercell interference. The antenna can support up to $4times 4$ multiple-input and multiple-output (MIMO) systems. The isolation between different ports exceed 28 dB over the commercial long term evolution bands 3 and 7. The multiport matching bandwidth of the antenna (>-0.3 dB) extends over 1700–3000 MHz range. The antenna is mechanically robust and can withstand a weight of 40 ton. MIMO performance of this antenna is verified by virtue of field measurements. A comparative study between the proposed antenna and a classic half-wavelength dipole antenna is presented highlighting the advantages of the proposed antenna. Finally, its compliance with the exposure limits for nonionizing radiation is also demonstrated.
Auteurs: Nima Jamaly;Pavle Belanovic;Damiano Scanferla;Hugo Lehmann;Carine Genoud;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2318 - 2327
Editeur: IEEE
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» Uncertainty Marginal Price, Transmission Reserve, and Day-Ahead Market Clearing With Robust Unit Commitment
Résumé:
The increasing penetration of renewable energy in recent years has led to more uncertainties in power systems. These uncertainties have to be accommodated by flexible resources (i.e., upward and downward generation reserves). In this paper, a novel concept, Uncertainty Marginal Price (UMP), is proposed to price both the uncertainty and generation reserve. At the same time, the energy is priced at Locational Marginal Price (LMP). A novel market clearing mechanism is proposed to credit the generation and reserve and to charge the load and uncertainty within the robust unit commitment in the day-ahead market. We derive the UMPs and LMPs in the robust optimization framework. UMP helps allocate the cost of generation reserves to uncertainty sources. We prove that the proposed market clearing mechanism leads to partial market equilibrium. We find that transmission reserves must be kept explicitly in addition to generation reserves for uncertainty accommodation. We prove that transmission reserves for ramping delivery may lead to Financial Transmission Right (FTR) underfunding in existing markets. The FTR underfunding can be covered by congestion fund collected from uncertainty payment in the proposed market clearing mechanism. Simulations on a six-bus system and the IEEE 118-bus system are performed to illustrate the new concepts and the market clearing mechanism.
Auteurs: Hongxing Ye;Yinyin Ge;Mohammad Shahidehpour;Zuyi Li;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1782 - 1795
Editeur: IEEE
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» Undergraduate Electronics Projects Based on the Design of an Optical Wireless Audio Transmission System
Résumé:
The two projects presented in this paper can be used either as two separate assignments in two different semesters or as a final assignment for undergraduate students of electrical engineering. They have two main objectives: first, to teach basic electronic circuit design concepts and, second, to motivate the students to learn more about analog circuit design. The two projects are: 1) the design of an audio power amplifier, and 2) the design of an amplitude-modulated optical link with a pulsed light-emitting diode (LED) at the emitter and a photodiode and a transimpedance amplifier at the receiver. An audio signal is used to modulate the oscillator that drives the LED, and the receiver demodulates this signal to produce an audio signal (music, for example) that can be sent to a loudspeaker. The intent of this optical communication system was to allow students to design and build various electronic circuits that have an overall objective and a clear practical application. Students are motivated by using this system to transmit, receive, and listen to their own music.
Auteurs: Luis Bica Oliveira;Nuno Paulino;João P. Oliveira;Rui Santos-Tavares;Nuno Pereira;João Goes;
Apparue dans: IEEE Transactions on Education
Date publication: 05.-2017, volume: 60, issue:2, pages: 105 - 111
Editeur: IEEE
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» Unemployment: Pick a number [Numbers Don't Lie]
Résumé:
Many economic statistics are notoriously unreliable, and the reason often has to do with what's included in the measurement and what's left out. Gross domestic product offers a good example of a measure that leaves out key environmental externalities, such as soil erosion, biodiversity loss, and effects of climate change. . Measuring unemployment is also an exercise in exclusion. Casual consumers of U.S. economic news are familiar with only the official figure, which put the country's total unemployment at 4.8 percent at the beginning of 2017. But that is just one of six alternatives used by the U.S. Bureau of Labor Statistics to quantify "labor underutilization."
Auteurs: Vaclav Smil;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 24 - 24
Editeur: IEEE
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» Unfolding for Time Petri Net
Résumé:
State Class Graph is a very useful tool to analyse Time Petri nets properties. It generates however a states explosion problem in large Petri nets. This can be overcome by using unfolding technique, which still imposes restrictions on time analysis. This paper proposes a relaxation in the unfolding process, which generates a new occurrence net, in which all temporal sequences are preserved.
Auteurs: Franck Carlos Velez Benito;Luiz Allan Kunzle;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 1001 - 1008
Editeur: IEEE
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» Unified Mechanism for Positive- and Negative-Bias Temperature Instability in GaN MOSFETs
Résumé:
We present a comprehensive study of bias temperature instability (BTI) in GaN MOSFETs under moderate positive and negative gate bias stress. We investigate the evolution of threshold voltage ( ${rm {V_T}})$ , maximum transconductance ( ${rm {g_{m,max}}})$ , and subthreshold swing (S). Our results show a universal continuous, symmetrical, and reversible ${rm {V_T}}$ shift and ${rm {g_{m, max}}}$ change as gate stress voltage ( $text {V}_{{{text {GS},text {stress}}}})$ increases from −5 to 5V at room temperature. The time evolution of ${rm {V_T}}$ is well described by a power law model. The voltage dependence, time dependence, and temperature dependence of our results suggest that for moderate gate bias stress, positive BTI and negative BTI are due to a single reversible mechanism. This is electron trapping/detrapping in preexisting oxide traps that form a defect band very close to the GaN/oxide interface and extend in energy beyond the conduction band edge of GaN and below the Fermi level at the channel surface at 0 V.
Auteurs: Alex Guo;Jesús A. del Alamo;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2142 - 2147
Editeur: IEEE
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» Uniform Stabilization of Nonlinear Systems With Arbitrary Switchings and Dynamic Uncertainties
Résumé:
We solve the problem of global uniform input-to-state stabilization of nonlinear switched systems with time-varying and periodic dynamics, with dynamic uncertainties, and with external disturbances. The switching signal is assumed to be unknown and the dynamics of the known components of the state vector is equivalent to the general triangular form (GTF) with non-invertible input-output maps. In our first and most general result, we prove that, if the dynamic uncertainty is treated as external disturbance, then the general triangular form system can be stabilized with arbitrarily small gain w.r.t. the dynamic uncertainty by means of a switching-independent, smooth and periodic feedback. Hence, using a suitable extension of the well-known small gain theorem to our case of switched systems with arbitrary switchings, we obtain the uniform input-to-state stabilization of the entire interconnected system. The second part of the paper addresses a more special case of triangular form (TF) switched systems with right-invertible input-output (I-O) maps with unknown switchings and with dynamic uncertainties. We show that the design becomes simpler and more constructive and the controllers become time-invariant if the dynamics is autonomous in this special case. Finally, we consider an example with explicit design of the stabilizing controllers.
Auteurs: S. S. Pavlichkov;S. N. Dashkovskiy;C. K. Pang;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2207 - 2222
Editeur: IEEE
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» Unipolar Differential Logic for Large-Scale Integration of Flexible aIGZO Circuits
Résumé:
A new unipolar differential logic (UDL) for the large-scale integration of amorphous In-Ga-Zn-O (aIGZO) digital circuits is proposed. Only single-threshold single-gate and aIGZO thin-film transistors are required. The proposed UDL logic gates are very insensitive to transistor parameter variations (i.e., threshold voltage, mobility, off-current, and subthreshold slope), which are inherently due to large-area low-temperature fabrication processes and operating conditions. To assess the UDL effectiveness, a wide range of parameter variations is considered: and, owing to the proposed architecture up to 1.5 $times$ 107 UDL gates that can be integrated with a yield that is greater than 90%.
Auteurs: Matteo Venturelli;Fabrizio Torricelli;Matteo Ghittorelli;Luigi Colalongo;Anna Richelli;Zsolt Miklós Kovács-Vajna;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 565 - 569
Editeur: IEEE
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» Unit Commitment Under Gas-Supply Uncertainty and Gas-Price Variability
Résumé:
We propose a two-stage mixed-integer linear stochastic optimization model to analyze the scheduling of electricity-production units under natural gas-supply uncertainty due to pipeline congestion and natural gas-price variability. The first stage of this stochastic optimization model represents the day-ahead scheduling (i .e., unit commitment) stage, while the second stage represents actual real-time operations through a number of scenarios. We use this model to analyze the effect on unit commitment and dispatch of two types of natural gas-supply conditions. First, we analyze a case involving low-cost natural gas supply with natural gas-transmission issues related to potential gas-pipeline congestion. We then examine a case involving higher-cost natural gas, which is used solely to attain feasibility with fast-ramping events. The first case mimics situations in the ISO New England system, in which relatively low-cost natural gas supply is uncertain in cold-weather conditions due to natural gas-transmission bottlenecks. The second case is reminiscent of situations in the California ISO system, in which relatively expensive but flexible natural gas-fired units need to be used to handle rapid changes in net demand in the early mornings and late afternoons.
Auteurs: Bining Zhao;Antonio J. Conejo;Ramteen Sioshansi;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2394 - 2405
Editeur: IEEE
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» Universal Compact Model for Thin-Film Transistors and Circuit Simulation for Low-Cost Flexible Large Area Electronics
Résumé:
Thin-film transistors (TFT) in hydrogenated amorphoussilicon, amorphousmetal oxide, andsmallmolecule and polymer organic semiconductors would all hold promise as potential device candidates to large area flexible electronics applications. A universal compact dc model was developed with a proper balance between the physical and mathematical approaches for these thin-film transistors (TFTs). It can capture the common key parameters used for device performance benchmarking of the different TFTs while being applicable to a wide range of TFT technologies in different materials and device structures. Based on this model, a user-friendly tool was developed to provide an interactive way for convenient parameter extraction. The model is continuous from the off-state and subthreshold regimes to the above-threshold regime, avoiding the convergence problems when being used in SPICE circuit simulations. Finally, for verification, it was implemented into a SPICE circuit simulator using Verilog-A to simulate a TFT circuit examplewith the simulated results agreeing verywell with the experimental measurements.
Auteurs: Jiaqing Zhao;Pengfei Yu;Shi Qiu;Qinghang Zhao;Linrun Feng;Simon Ogier;Wei Tang;Jiali Fan;Wenjiang Liu;Yongpan Liu;Xiaojun Guo;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2030 - 2037
Editeur: IEEE
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» Universal Compressed Sensing for Almost Lossless Recovery
Résumé:
In this paper, the problem of developing universal algorithms for noiseless compressed sensing of stochastic processes is studied. First, Rényi’s notion of information dimension (ID) is generalized to continuous-valued discrete-time stationary processes. This provides a measure of complexity for such processes and is connected to the rate of measurement (sampling rate) required for their accurate recovery. Then, based on Occam’s razor, a minimum entropy pursuit (MEP) optimization approach for universal compressed sensing is proposed. It is proven that, for any stationary process satisfying certain mixing conditions, if the sampling rate is larger than the ID of the source process, MEP optimization can reliably recover the source vector almost losslessly, without having any prior information about its distribution. Then, a Lagrangian-type relaxation of MEP optimization problem, referred to as Lagrangian-MEP, is studied. It is shown that Lagrangian-MEP is identical to an implementable algorithm proposed by Baron and coauthors, and for the right choice of parameters, has the same asymptotic performance as MEP optimization. Finally, it is proven that Lagrangian-MEP is robust to small measurement noise.
Auteurs: Shirin Jalali;H. Vincent Poor;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2933 - 2953
Editeur: IEEE
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» Unlocking New Sources of Flexibility: CLASS: The World's Largest Voltage-Led Load-Management Project
Résumé:
The Significant growth of wind and photovoltaic generation experienced in many countries around the world will soon challenge the ability of transmission system operators (TSOs) to guarantee the security of supply. To cope with such future low-carbon electricity systems, it is imperative to increase the portfolio of flexibility sources in a cost-effective and sustainable manner. This is likely to require exploring solutions beyond the use of traditional players connected at higher voltages, such as fast-acting generation plants and large customers.
Auteurs: Andrea Ballanti;Luis Nando Ochoa;Kieran Bailey;Steve Cox;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 05.-2017, volume: 15, issue:3, pages: 52 - 63
Editeur: IEEE
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» Unsupervised Classification in Hyperspectral Imagery With Nonlocal Total Variation and Primal-Dual Hybrid Gradient Algorithm
Résumé:
In this paper, a graph-based nonlocal total variation method is proposed for unsupervised classification of hyperspectral images (HSI). The variational problem is solved by the primal-dual hybrid gradient algorithm. By squaring the labeling function and using a stable simplex clustering routine, an unsupervised clustering method with random initialization can be implemented. The effectiveness of this proposed algorithm is illustrated on both synthetic and real-world HSI, and numerical results show that the proposed algorithm outperforms other standard unsupervised clustering methods, such as spherical K -means, nonnegative matrix factorization, and the graph-based Merriman-Bence-Osher scheme.
Auteurs: Wei Zhu;Victoria Chayes;Alexandre Tiard;Stephanie Sanchez;Devin Dahlberg;Andrea L. Bertozzi;Stanley Osher;Dominique Zosso;Da Kuang;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2786 - 2798
Editeur: IEEE
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» Unsupervised Hyperspectral Band Selection by Fuzzy Clustering With Particle Swarm Optimization
Résumé:
Due to the lack of label information and the intrinsic complexity of hyperspectral images (HSIs), unsupervised band selection is always one of the most challenging tasks in HSI processing. Fuzzy clustering is a promising technique for unsupervised band selection, which can partition unlabeled data into groups effectively. However, due to the limits of its optimization process, standard fuzzy clustering is sensitive to initialization and easy to be trapped in a local optimum. To address the limits, a novel unsupervised band selection method is proposed, combining fuzzy clustering with particle swarm optimization (PSO). A newly designed PSO algorithm is introduced to improve the performance of fuzzy clustering band selection. Moreover, a new strategy is designed to select representative cluster centers according to the characteristics of HSIs. The experimental results indicate that the proposed method has the ability to select high-quality band subsets with good and robust performance on HSI classification.
Auteurs: Mingyang Zhang;Jingjing Ma;Maoguo Gong;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 773 - 777
Editeur: IEEE
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» Unsupervised Polarimetric SAR Image Classification Using $mathcal {G}_{p}^{0}$ Mixture Model
Résumé:
This letter proposes a polarimetric synthetic aperture radar image classification method based on the expectation–maximization algorithm. It is an unsupervised algorithm that determines the number of classes in the scene following a top–down strategy using a covariance-based hypothesis test. A $mathcal {G}_{p}^{0}$ mixture model is used to describe multilook complex polarimetric data, and the proposed algorithm is tested in simulated and real data sets obtaining good results. The classification performance is evaluated by means of the overall accuracy and the kappa indices obtained from the Monte Carlo analysis. Finally, the results are compared with those obtained by other classic and recently developed classification algorithms.
Auteurs: Juan I. Fernández-Michelli;Martín Hurtado;Javier A. Areta;Carlos H. Muravchik;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 754 - 758
Editeur: IEEE
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» Using Continuous Power Modulation for Exchanging Local Channel State Information
Résumé:
This letter provides a simple but efficient technique, which allows each transmitter of an interference network, to exchange local channel state information with the other transmitters. One salient feature of the proposed technique is that a transmitter only needs measurements of the signal power at its intended receiver to implement it, making direct inter-transmitter signaling channels unnecessary. The key idea to achieve this is to use a transient period during which the continuous power level of a transmitter is taken to be the linear combination of the channel gains to be exchanged.
Auteurs: Chao Zhang;Samson Lasaulce;Vineeth S. Varma;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1187 - 1190
Editeur: IEEE
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» Using Storage-Capacity Rights to Overcome the Cost-Recovery Hurdle for Energy Storage
Résumé:
Energy storage is unique in that it can provide multiple services. This feature raises cost-recovery issues for storage, due to the combination of competitive markets and ratebased cost recovery used in many power systems today. This hybrid regulatory paradigm relies on classifying assets as providing competitively prices or unpriced services and handling cost recovery based on that classification. Some recent regulatory precedents suggest that storage developers must choose between classifying their assets as providing competitively priced or unpriced services. In the former case, storage costs must be recovered through the market. If an asset is classified as providing only unpriced services, costs can be recovered through the ratebase. This regulatory design can hamper cost recovery for storage and may lead to inefficient storage investment and use. We propose an alternate solution whereby storage-capacity rights are auctioned to third parties that use their rights for priced or unpriced services. Storage-capacity rights disentangle storage cost recovery from the regulatory treatment of its end use. We formulate the storage-capacity auction model and demonstrate how to efficiently price storage-capacity rights. We show that the revenues earned by the storage owner through the auction equals the imputed marginal value of storage capacity, as revealed by the market bids.
Auteurs: Ramteen Sioshansi;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2028 - 2040
Editeur: IEEE
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» Validation of MODIS Sea Surface Temperature Product in the Coastal Waters of the Yellow Sea
Résumé:
Sea surface temperature (SST) plays a fundamental role in the exchange of heat, momentum, and water vapor between atmosphere and ocean. Therefore, measurement of SST has been done from ships, buoys, offshore platforms, and satellites. During past decades satellites are being increasingly used, because datasets over wide areas can be obtained. In this paper, moderate resolution imaging spectroradiometer (MODIS) on board Terra and Aqua SST products were examined and validated for coastal waters in the Yellow Sea by using the in situ buoy data. A strict match-up method was adopted in view of the complexity and variability of coastal area, resulting in 154 and 164 match-ups for Terra and Aqua, respectively. The MODIS SST agreed well with in situ buoy SST, with squared correlation coefficients R2 of 0.989 for Terra, and 0.987 for Aqua. Relative to in situ SSTs, the satellite-derived SSTs had a bias of 0.23 °C and 0.06 °C, a standard deviation of 0.79 °C and 0.85 °C, and a root mean square error of 0.83 °C and 0.85 °C, for Terra and Aqua. The differences between MODIS and in situ SST exhibited apparent seasonal variations. The accuracy of MODIS SST products for spring and summer were lower than those for autumn and winter, which could be caused by frequent sea fog along the southern coast of Shandong Peninsula. The SST bias approximately depended on wind velocity; low wind velocity could enhance the diurnal SST amplitude and the bulk-skin temperature difference. However, there is no significant dependence of the bias on air-sea temperature difference or surface flow velocity.
Auteurs: Yanling Hao;Tingwei Cui;Vijay P. Singh;Jie Zhang;Ruihong Yu;Zhilei Zhang;
Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Date publication: 05.-2017, volume: 10, issue:5, pages: 1667 - 1680
Editeur: IEEE
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» Variability of Terahertz Transmission Measured in Live Plant Leaves
Résumé:
Terahertz (THz) transmission was measured in the live leaves of seven species of common food plants. Multiple leaves of each plant were examined, and large variability of transmission loss was revealed. The results have implications for THz applications for agricultural sensing and for the design of THz communications links.
Auteurs: Armita Afsharinejad;Alan Davy;Mira Naftaly;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 636 - 638
Editeur: IEEE
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» Variable Selection and Identification of High-Dimensional Nonparametric Additive Nonlinear Systems
Résumé:
This paper considers variable selection and identification of dynamic additive nonlinear systems via kernel-based nonparametric approaches, where the number of variables and additive functions may be large. Variable selection aims to find which additive functions contribute and which do not. The proposed variable selection consists of two successive steps. At the first step, one estimates each additive function by kernel-based nonparametric identification approaches without suffering from the curse of dimensionality. At the second step, a nonnegative garrote estimator is applied to identify which additive functions are nonzero by utilizing the obtained nonparametric estimates of each function. Under weak conditions, the nonparametric estimates of each additive function can achieve the same asymptotic properties as for 1D nonparametric identification based on kernel functions. It is also established that the nonnegative garrote estimator turns a consistent estimate for each additive function into a consistent variable selection with probability one as the number of samples tends to infinity. Two simulation examples are presented to verify the effectiveness of the variable selection and identification approaches proposed in the paper.
Auteurs: Biqiang Mu;Wei Xing Zheng;Er-Wei Bai;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2254 - 2269
Editeur: IEEE
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» Variable-Angle Phase-Shifted PWM for Multilevel Three-Cell Cascaded H-Bridge Converters
Résumé:
Multilevel cascaded H-bridge converters have become a mature technology for applications where high-power medium ac voltages are required. Normal operation of multilevel cascaded H-bridge converters assumes that all power cells have the same dc voltage, and each power cell generates the same voltage averaged over a sampling period using a conventional phase-shifted pulse width modulation (PWM) technique. However, this modulation method does not achieve good results under unbalanced operation per H-bridge in the power converter, which may happen in grid-connected applications such as photovoltaic or battery energy storage systems. In the paper, a simplified mathematical analysis of the phase-shifted PWM technique is presented. In addition, a modification of this conventional modulation method using variable shift angles between the power cells is introduced. This modification leads to the elimination of harmonic distortion of low-order harmonics due to the switching (triangular carrier frequency and its multiples) even under unbalanced operational conditions. The analysis is particularized for a three-cell cascaded H-bridge converter, and experimental results are presented to demonstrate the good performance of the proposed modulation method.
Auteurs: Abraham Marquez;Jose I. Leon;Sergio Vazquez;Ramon Portillo;Leopoldo G. Franquelo;Emilio Freire;Samir Kouro;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3619 - 3628
Editeur: IEEE
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» Variable-Length Prefix Codes With Multiple Delimiters
Résumé:
Let $m_{1},m_{2},ldots, m_{t}$ be a fixed set of natural integers given in ascending order. A multi-delimiter code $D_{m_{1},ldots, m_{t}}$ consists of $t$ words of the form $1^{m_{i}}0$ and all other binary words with suffixes having one of the forms $01^{m_{i}}0$ that cannot occur in other places of a word, $i=1,ldots, t$ . Completeness, universality, and density characteristics of multi-delimiter codes are proved. Encoding of integers by multi-delimiter codes is considered in detail. For these codes, fast byte aligned decoding algorithms are also discussed. The comparison of compression rate and decoding speed of Fibonacci codes, $(s,c)$ -dense codes and different multi-delimiter codes is presented. By many useful properties, multi-delimiter codes are superior to Fibonacci codes.
Auteurs: Anatoly V. Anisimov;Igor O. Zavadskyi;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 2885 - 2895
Editeur: IEEE
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» Variation of Threshold Voltage With Temperature in Impact Ionization-Induced Steep Switching Si and Ge Junctionless MOSFETs
Résumé:
In this paper, we report on the anomalous behavior of threshold voltage ( ${V} _{sf th})$ with temperature in junctionless (JL) transistors. It is shown that both positive and negative values of temperature coefficient of threshold voltage (dV $_{sf th}$ /dT) in nMOS Si and Ge JL devices can occur at higher drain biases. At lower temperatures, ${V} _{sf th}$ reduces with a decrease in temperature due to the dominance of bipolar effects over thermal generation of carriers, whereas at higher temperatures, thermal generation results in essentially unipolar characteristics, and ${V} _{sf th}$ reduces with increase in temperature. It is also shown that zero temperature coefficient condition shall be nonexistent under dominant bipolar conduction over unipolar operation. Results show new viewpoints to understand the two contrasting physical mechanisms leading to positive and negative dV $_{sf th}$ /dT values in JL devices.
Auteurs: Manish Gupta;Abhinav Kranti;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2061 - 2066
Editeur: IEEE
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» Variation-Tolerant Sensing Circuit for Ultralow-Voltage Operation of Spin-Torque Transfer Magnetic RAM
Résumé:
Although promising as a future memory solution, the spin-torque transfer magnetic RAM has critical drawbacks due to the small operation margin in low supply voltage and large area of the sensing circuit. To overcome these disadvantages, we propose a novel sensing circuit that utilizes the data-dependent body-bias scheme with a single reference cell. Through Monte Carlo simulations using 45-nm process technology model parameters, the proposed circuit is verified to be highly robust to the variations in threshold voltage and cell resistance at ultralow supply voltages without sensing speed degradation. The proposed circuit has a read access pass yield of 96.5% for 16-Mb memory at $mathbf{V}_{mathbf{DD}} = 0.7 mathbf{V}$ when the standard deviation of cell resistance is 10%. In addition, the area overhead is also reduced by 79% compared to the conventional sensing circuit.
Auteurs: Kangwook Jo;Hongil Yoon;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 570 - 574
Editeur: IEEE
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» Variational Bayesian Inference for FIR Models With Randomly Missing Measurements
Résumé:
This paper is concerned with parameter and output estimation for industrial processes described by finite impulse response model in presence of randomly missing output measurements. The statistical models for describing the estimation problems are given and the prior distributions over unknown parameters and variables are constructed. The estimation problems with incomplete dataset are formulated in the variational Bayesian framework and the problems of randomly missing measurements, overfitting, and high sensitivity of parameter estimate to noise are handled simultaneously. The iterative formulas to estimate the posterior distributions of missing output data and unknown parameters based on available process data are derived. The simulation example and the hybrid tank system experiment are performed to demonstrate the effectiveness of the proposed method.
Auteurs: Xianqiang Yang;Shen Yin;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4217 - 4225
Editeur: IEEE
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» Vehicles of the Future: A Survey of Research on Safety Issues
Résumé:
Information and communication technologies (ICTs) have a profound impact on the current state and envisioned future of automobiles. This paper presents an overview of research on ICT-based support and assistance services for the safety of future connected vehicles. A general classification and a brief description of the focus areas for research and development in this direction are given under the titles of vehicle detection, road detection, lane detection, pedestrian detection, drowsiness detection, and collision avoidance. Following an overview and taxonomy of the reviewed research articles, a categorized literature survey of safety critical applications is presented in detail. Future research directions are also highlighted.
Auteurs: Cem Bila;Fikret Sivrikaya;Manzoor A. Khan;Sahin Albayrak;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1046 - 1065
Editeur: IEEE
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» Velocity Estimation in Medical Ultrasound [Life Sciences]
Résumé:
This article describes the application of signal processing in medical ultrasound velocity estimation. Special emphasis is on the relation among acquisition methods, signal processing, and estimators employed. The description spans from current clinical systems for one-and two-dimensional (1-D and 2-D) velocity estimation to the experimental systems for three-dimensional (3-D) estimation and advanced imaging sequences, which can yield thousands of images or volumes per second with fully quantitative flow estimates. Here, spherical and plane wave emissions are employed to insonify the whole region of interest, and full images are reconstructed after each pulse emission for use in velocity estimation.
Auteurs: Jorgen Jensen;Carlos Armando Villagomez Hoyos;Simon Holbek;Kristoffer Lindskov Hansen;
Apparue dans: IEEE Signal Processing Magazine
Date publication: 05.-2017, volume: 34, issue:3, pages: 94 - 100
Editeur: IEEE
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» Versatile and Accurate Schemes of Discretization in the Scattering Analysis of 2-D Composite Objects With Penetrable or Perfectly Conducting Regions
Résumé:
The method-of-moment discretization of boundary integral equations in the scattering analysis of closed infinitely long (2-D) objects, perfectly conducting (PEC) or penetrable, is traditionally carried out with continuous piecewise linear basis functions, which embrace pairs of adjacent segments. This is numerically advantageous because the discretization of the transversal component of the scattered fields, electric (TE) or magnetic (TM), becomes free from hypersingular Kernel contributions. In the analysis of composite objects, though, the imposition of the continuity requirement around junction nodes, where the boundaries of several regions intersect, becomes especially awkward. In this paper, we present, for the scattering analysis of composite objects, a new combined discretization of the Poggio–Miller–Chang–Harrington–Wu–Tsai (PMCHWT) integral equation, for homogeneous dielectric regions, and the electric-field integral equation, for PEC regions, such that the basis functions are defined strictly on each segment, with no continuity constraint between adjacent segments. We show the improved observed accuracy with the proposed TE-PMCHWT implementation on several dielectric objects with sharp edges and corners and moderate or high contrasts. Furthermore, we illustrate the versatility of these schemes in the analysis of 2-D composite piecewise homogeneous objects without sacrificing accuracy with respect to the conventional implementations.
Auteurs: Ivan Sekulic;Eduard Ubeda;Juan M. Rius;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2494 - 2506
Editeur: IEEE
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» Vibrational Responses of Bound and Nonbound Targeted Lipid-Coated Single Microbubbles
Résumé:
One of the main challenges for ultrasound molecular imaging is acoustically distinguishing nonbound microbubbles from those bound to their molecular target. In this in vitro study, we compared two types of in-house produced targeted lipid-coated microbubbles, either consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, C16:0 (DPPC) or 1,2-distearoyl-sn-glycero-3-phosphocholine, C18:0 (DSPC) as the main lipid, using the Brandaris 128 ultrahigh-speed camera to determine vibrational response differences between bound and nonbound biotinylated microbubbles. In contrast to previous studies that studied vibrational differences upon binding, we used a covalently bound model biomarker (i.e., streptavidin) rather than physisorption, to ensure binding of the biomarker to the membrane. The microbubbles were insonified at frequencies between 1 and 4 MHz at pressures of 50 and 150 kPa. This paper shows lower acoustic stability of bound microbubbles, of which DPPC-based microbubbles deflated most. For DPPC microbubbles with diameters between 2 and $4~mu text{m}$ driven at 50 kPa, resonance frequencies of bound microbubbles were all higher than 1.8 MHz, whereas those of nonbound microbubbles were significantly lower. In addition, the relative radial excursions at resonance were also higher for bound DPPC microbubbles. These differences did not persist when the pressure was increased to 150 kPa, except for the acoustic stability which further decreased. No differences in resonance frequencies were observed between bound and nonbound DSPC microbubbles. Nonlinear responses in terms of emissions at the subharmonic and second harmonic frequencies were similar for bound and nonbound microbubbles at both pressures. In conclusion, we identified differences in vibrational responses of bound DPPC microbubbles with diameters between 2 and $4~mu text{m}$ that distinguish them from nonbound ones.
Auteurs: Tom van Rooij;Inés Beekers;Kirby R. Lattwein;Antonius F. W. van der Steen;Nico de Jong;Klazina Kooiman;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 785 - 797
Editeur: IEEE
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» Virtual Synchronous Power Strategy for Multiple HVDC Interconnections of Multi-Area AGC Power Systems
Résumé:
Automatic generation control (AGC) in multi-area interconnected power systems is experiencing several adaptions due to increasing level of power converter based components in the system. The concept of virtual synchronous power (VSP) to simulate the dynamic effects of virtual inertia emulations by HVDC links for higher level control applications is introduced and reflected in the multi-area AGC model. By using this proposed combination in the AGC model, the dynamic performance of the studied system shows a significant improvement. The proposed formulation is generalized for multi-area systems with multiple HVDC links. The active power loop control in VSP-based HVDC links has a second-order characteristic, which makes a simultaneous enabling of damping and inertia emulations into the system. Trajectory sensitivities are also used to analyze the effects of VSP's parameters on the system stability. The effectiveness of the proposed concept on dynamic improvements is tested through MATLAB simulation of a four-area system.
Auteurs: Elyas Rakhshani;Daniel Remon;Antoni Mir Cantarellas;Jorge Martinez Garcia;Pedro Rodriguez;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1665 - 1677
Editeur: IEEE
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» Visual Servoed Zebrafish Larva Heart Microinjection System
Résumé:
As a typical vertebrate model animal, the zebrafish has become a popular organism. For studying a specific disease mechanism, an efficient zebrafish microinjection technology is required. Compared with widely researched embryo injection technology, zebrafish larva injection has not been developed intensively. In particular, zebrafish larva heart injection is generally operated manually, which is laborious and time consuming. In this paper, we present a visual servo system of zebrafish larva heart microinjection, capable of visually determining larva heart position and controlling the microactuators. The larva's body is first rotated to be perpendicular to holding pipette; then, a robust visual detection algorithm against different larva gestures is presented to obtain its heart position in the horizontal plane. A rolling model is further constructed based on a database of larva body slice figures to estimate the heart height. Experimental results show that a satisfied success and survival rate can be obtained by presented methods, which is comparable to manual operation.
Auteurs: Songlin Zhuang;Weiyang Lin;Huijun Gao;Xinxin Shang;Li Li;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3727 - 3736
Editeur: IEEE
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» Voltage Mode Doherty Power Amplifier
Résumé:
This paper presents a new wideband Doherty amplifier technique that can achieve high efficiency while maintaining excellent linearity. By modifying a “forgotten” topology originally proposed by Doherty, a new Doherty amplifier architecture is realized with two voltage mode power amplifiers (PAs) and transformers, thus eliminating a narrowband impedance inverter. The voltage mode PA is implemented using switched capacitor PA techniques. The PA is fabricated in 65-nm low-leakage CMOS and achieves 24-dBm saturated power (at the standard supply voltage) with PAE of 45% at peak power and 34% at 5.6-dB back-off over 750 to 1050 MHz 1 dB bandwidth. With memory-less linearization, the PA can transmit 40 MHz 256-QAM 9 dB peak-to-average power ratio 802.11ac modulation centered at 900 MHz meeting the spectral mask with measured EVM of −34.8 dB and 22% PAE without backing off or equalization.
Auteurs: Voravit Vorapipat;Cooper S. Levy;Peter M. Asbeck;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 05.-2017, volume: 52, issue:5, pages: 1295 - 1304
Editeur: IEEE
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» Water Ingress Detection in Low-Pressure Gas Pipelines Using Distributed Temperature Sensing System
Résumé:
In a distribution network of low-pressure gas pipelines, the situation of gas leak can be further aggravated when groundwater enters the pipeline through leaks and eventually blocks the gas flow. This will have critical implications on the gas supply to the customers. This is termed as “water ingress,” which typically happens only in low-pressure distribution networks, and not in high-pressure transmission networks. In order to find the location of water ingress, distributed temperature sensing (DTS) system has been used experimentally. The results show significant temperature change immediately after the onset of water ingress, and with data post-processing based on temporal difference, location information of the leak can be obtained. With a selected time window of interest, the inclination of gas pipeline is also indicated by the differenced temperature profiles. The DTS system is still capable of identifying the position, even if the location of water ingress is changed.
Auteurs: Libo Wang;Srivathsan Chakaravarthi Narasimman;Sugunakar Reddy Ravula;Abhisek Ukil;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3165 - 3173
Editeur: IEEE
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» Wavelet Transformation-Based Fuzzy Reflex Control for Prosthetic Hands to Prevent Slip
Résumé:
A wavelet transformation-based fuzzy reflex control method is proposed to prevent slip and maintain stable grasping posture for prosthetic hands. A key component of the control method is that the response time from slip detection to slip prevention is very short. The proposed control method mainly includes slip detection, reflex grasping force estimation, and use of a reflex controller. In the slip detection, initial slip information can be rapidly obtained via wavelet transformation as soon as disturbances cause the grasped object to slip. This shortens the response time of the reflex control. The initial slip information can then trigger the reflex control. In the grasping estimation, a reflex force estimation model is presented to estimate a force increment that is used to adjust to the desired force. In the reflex controller, a fuzzy logic controller is adopted to track the desired force. Finally, the proposed control method is applied to control a prosthetic hand with a single degree of freedom. The experimental results show that the proposed control method can adjust the grasping force and effectively prevent slip under disturbances. The time of slip prevention is less than 160 ms.
Auteurs: Hua Deng;Yi Zhang;Xiao-Gang Duan;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3718 - 3726
Editeur: IEEE
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» What Features Can Tell Us about Shape
Résumé:
3D shape representations are essential when storing shape information for natural and manmade objects. To make use of shape information, many applications require shape-processing functionality, such as for search, annotation, classification, modeling, restoration, or collection exploration. This article discusses feature-based approaches and how they can support such functionality.
Auteurs: Tobias Schreck;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 82 - 87
Editeur: IEEE
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» What Happened to Software Metrics?
Résumé:
A panel of seven experts discuss the past 40 years of software metrics, with a focus on evidence-based methods.
Auteurs: Jeffrey Voas;Rick Kuhn;
Apparue dans: Computer
Date publication: 05.-2017, volume: 50, issue:5, pages: 88 - 98
Editeur: IEEE
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» What Is Worth Your Time? [From the Editor's Desk]
Résumé:
Auteurs: Alfy Riddle;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 6 - 22
Editeur: IEEE
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» What's Going on at CMD? [Chapter News]
Résumé:
Presents information on recent activities and meeting of various IAS society chapters.
Auteurs: Peter Magyar;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 05.-2017, volume: 23, issue:3, pages: 73 - 74
Editeur: IEEE
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» What's Happening at IEEE: How It Could Impact the IEEE Power & Energy Society [Leader's Corner]
Résumé:
This article presents what is happening within PES and the IEEE that could impact the Society and attempts being bade to continue and grow PES membership, maintain financial growth, and provide increased member value.
Auteurs: Alan C. Rotz;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 05.-2017, volume: 15, issue:3, pages: 8 - 14
Editeur: IEEE
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» What's New for IMS2017
Résumé:
Presents information on the IMS 2017 Conference.
Auteurs: Monte Watanabe;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 18 - 18
Editeur: IEEE
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» Wide Range Refractive Index Measurement Using a Multi-Angle Tilted Fiber Bragg Grating
Résumé:
The conventional single-angle tilted fiber Bragg grating (TFBG) can only excite a certain range of cladding modes, limiting it for refractive index (RI) measurement in a wide range. In this letter, we fabricate and demonstrate a multi-angle TFBG, in which five individual TFBGs with tilt angles ranging from 5° to 25° are sequentially inscribed along the core of a single mode fiber within a length of 20 mm. The multi-angle TFBG excites a continuous spectral comb of narrowband-cladding modes over a much wider wavelength range (>170 nm) than a single-angle TFBG, making it suitable for dynamic RI measurement over a wide range (1.15–1.45). We have experimentally measured aqueous solutions with RI ranging from 1.30 to 1.45 using the uncoated (by monitoring the cut-off mode) and gold-coated (by monitoring the surface Plasmon resonance) multi-angle TFBGs, and both methods show linear responses, with RI sensitivities about 500 nm/RIU.
Auteurs: Xiaoyong Chen;Jian Xu;Xuejun Zhang;Tuan Guo;Bai-Ou Guan;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 719 - 722
Editeur: IEEE
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» Wideband Gain MQW-SOA Modeling and Saturation Power Improvement in a Tri-Electrode Configuration
Résumé:
A semiphenomenological wideband model is proposed for both the material gain and the gain coefficient of a multiquantum well semiconductor optical amplifier (MQW-SOA). This analytical model is integrated in an SOA-dedicated simulation tool and validated experimentally over a wide range of bias currents, input powers, and wavelengths. We demonstrate the ability of multielectrode configurations to increase the saturation power of MQW-SOA without sacrificing either their noise figure or their optical gain bandwidth A tri-electrode configuration permits to obtain an enhancement of the MQW-SOA output saturation power of more than 3 dB over 100 nm while maintaining its optical bandwidth (defined at −1 dB) at about 76 nm.
Auteurs: T. Motaweh;P. Morel;A. Sharaiha;R. Brenot;A. Verdier;M. Guégan;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 2003 - 2009
Editeur: IEEE
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» Wideband Glass and Liquid Cylindrical Dielectric Resonator Antenna for Pattern Reconfigurable Design
Résumé:
A mode reconfigurable dielectric resonator antenna (DRA) to realize radiation pattern reconfiguration is presented for the first time. The DRA is composed of two zones: the inner zone is a solid cylinder fabricated by K9 glass ( $varepsilon _{r} = 6.85$ ) and the outer zone is filled with a dielectric liquid—ethyl acetate ( $varepsilon _{r} = 7.1$ ). Both of them are put into a cylindrical container fabricated by 3-D printing technology and excited by a single coaxial probe. The inner glass DRA is excited in its broadside HEM $_{mathrm {11delta }}$ mode when the ethyl acetate is pumped out, while the conical TM $_{mathrm {01delta }}$ mode is excited in the reconstituted cylindrical DRA when the ethyl acetate is pumped in. Consequently, a mechanical reconfiguration of broadside and conical radiation patterns can be achieved over a wide impedance bandwidth of 35.5% from 3.75 to 5.37 GHz. For demonstration, the reconfigurable DRA was fabricated and measured. The measured results of the standing wave ratio, radiation pattern, gain, and efficiency are discussed. Reasonable agreement between the measured and simulated results is observed.
Auteurs: Zhe Chen;Hang Wong;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2157 - 2164
Editeur: IEEE
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» Widely Linear Precoding for Large-Scale MIMO with IQI: Algorithms and Performance Analysis
Résumé:
In this paper, we study widely linear precoding techniques to mitigate in-phase/quadrature-phase (IQ) imbalance (IQI) in the downlink of large-scale multiple-input multiple-output (MIMO) systems. We adopt a real-valued signal model, which considers the IQI at the transmitter, and then develop widely linear zero-forcing (WL-ZF), widely linear matched filter, widely linear minimum mean-squared error, and widely linear block-diagonalization (WL-BD) type precoding algorithms for both single- and multiple-antenna users. We also present a performance analysis of WL-ZF and WL-BD. It is proved that without IQI, WL-ZF has exactly the same multiplexing gain and power offset as ZF, while when IQI exists, WL-ZF achieves the same multiplexing gain as ZF with ideal IQ branches, but with a minor power loss, which is related to the system scale and the IQ parameters. We also compare the performance of WL-BD with BD. The analysis shows that with ideal IQ branches, WL-BD has the same data rate as BD, while when IQI exists, WL-BD achieves the same multiplexing gain as BD without IQ imbalance. Numerical results verify the analysis and show that the proposed widely linear type precoding methods significantly outperform their conventional counterparts with IQI and approach those with ideal IQ branches.
Auteurs: Wence Zhang;Rodrigo C. de Lamare;Cunhua Pan;Ming Chen;Jianxin Dai;Bingyang Wu;Xu Bao;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 05.-2017, volume: 16, issue:5, pages: 3298 - 3312
Editeur: IEEE
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» Wind Power Providing Flexible Ramp Product
Résumé:
The deepening penetration of renewables in power systems has contributed to the increasing need for generation flexibility. Specifically, for short-term operations, flexibility here indicates that sufficient ramp capacity is available to respond to the varying load and intermittent generation. To address the growing needs for ramp capacity, markets for ramp products have been launched in practice such as those in California ISO and Midcontinent ISO. Sometimes, expensive fast-start units must be committed in real time to guarantee sufficient ramp capacity. Occasionally even worse, inadequate ramp capacity from the given generation portfolio might lead to curtailment of renewable generation or load shedding. Therefore, more supplies of ramp capacity are required. In fact, wind power producers (WPPs) are physically capable of offering ramp services, which gives us a potential option. In this paper, we attempt to explore the mechanism and economic impacts of including WPPs as ramp capacity providers. To conduct the analyses, a two-stage stochastic real-time unit commitment model considering ramp capacity adequacy is formulated. Case studies indicate that both the system and the WPPs can benefit in the proposed framework.
Auteurs: Runze Chen;Jianhui Wang;Audun Botterud;Hongbin Sun;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2049 - 2061
Editeur: IEEE
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» Wireless Charging System Considering Eddy Current in Cardiac Pacemaker Shell: Theoretical Modeling, Experiments, and Safety Simulations
Résumé:
Implantable cardiac pacemakers play a vital role in extending the lives of patients with cardiovascular diseases. The technique of wireless power transfer (WPT) via magnetic coupling resonance (MCR) makes it possible to wirelessly and uninterruptedly supply electricity for pacemakers from external. However, the eddy current in the metallic pacemaker shell seriously impacts the electric energy receiving by receiving coils, making the WPT system operate at low efficiency. To decrease eddy current effect and increase WPT efficiency, the precise implant position of receiving coils is theoretically and experimentally investigated in this paper. The electromagnetic model of pacemaker WPT system is built and the analytical solution of induced voltage across receiving coils is derived, which is verified by experiments. Accordingly, the minimum distance between the receiving coil and the pacemaker shell is reversely calculated for enough induced voltage. Experimental results show that supplied by a power source of 5.66 V/300 kHz, the pacemaker charging system successfully charged Lithium-ion battery from 3.98 (80% residual capacity) to 4.2 V within 30 min by a 0.15 mm thickness receiving coil implanted into 4 mm subcutaneously. On the safety of charging system, electromagnetic and thermal simulation results show that the maximum SAR and temperature rise in tissues are 36.8 W/kg and 0.66 $^circ$C, respectively. The results provide a theoretical and practical support for design of a wireless charging system.
Auteurs: Chunyan Xiao;Kangzheng Wei;Dingning Cheng;Yufeng Liu;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3978 - 3988
Editeur: IEEE
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» Women in Microwaves at IMS2017: Bringing Inspiration to the Islands
Résumé:
Provides a notice of upcoming conference events of interest to practitioners and researchers.
Auteurs: Carolynn Kitamura;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 79 - 81
Editeur: IEEE
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» Words Matter: Scene Text for Image Classification and Retrieval
Résumé:
Text in natural images typically adds meaning to an object or scene. In particular, text specifies which business places serve drinks (e.g., cafe, teahouse) or food (e.g., restaurant, pizzeria), and what kind of service is provided (e.g., massage, repair). The mere presence of text, its words, and meaning are closely related to the semantics of the object or scene. This paper exploits textual contents in images for fine-grained business place classification and logo retrieval. There are four main contributions. First, we show that the textual cues extracted by the proposed method are effective for the two tasks. Combining the proposed textual and visual cues outperforms visual only classification and retrieval by a large margin. Second, to extract the textual cues, a generic and fully unsupervised word box proposal method is introduced. The method reaches state-of-the-art word detection recall with a limited number of proposals. Third, contrary to what is widely acknowledged in text detection literature, we demonstrate that high recall in word detection is more important than high f-score at least for both tasks considered in this work. Last, this paper provides a large annotated text detection dataset with 10 K images and 27 601 word boxes.
Auteurs: Sezer Karaoglu;Ran Tao;Theo Gevers;Arnold W. M. Smeulders;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 05.-2017, volume: 19, issue:5, pages: 1063 - 1076
Editeur: IEEE
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» Workload-Aware Elastic Striping With Hot Data Identification for SSD RAID Arrays
Résumé:
Redundant array of independent disk (RAID) offers a good option to provide device-level fault tolerance for solid-state drives (SSDs). However, parity update with either read–modify–write or read–reconstruct–write may introduce a lot of extra I/Os and thus significantly degrades SSD RAID performance. To reduce the parity update cost, elastic striping chooses to reconstruct new stripes with only the newly updated data chunks instead of directly updating parity chunks. However, it necessitates an RAID-level garbage collection (GC) process, which may incur a very high cost due to the mixture of hot and cold data chunks. To address this problem, we follow the idea of elastic striping and propose a workload-aware scheme (WAS) to reduce the RAID-level GC cost so as to improve the performance and endurance of SSD RAID. In particular, we first develop a novel lightweight hot data identification scheme which requires only a very small computation time and memory cost, then propose a hotness-aware elastic striping approach to separately write data chunks with different hotness to different regions in SSD RAID. To evaluate the effectiveness and efficiency of our WAS, we implement a prototype system on RAID-5 and RAID-6 arrays composed of commercial SSDs. Experimental results show that compared to original elastic striping, our scheme reduces 30.0%–70.6% (and 23.9%–63.2%) of chunk writes under the RAID-5 (and RAID-6) settings, and also reduces the average response time by 60.9%–79.3% (and 56.8%–80.9%) for RAID-5 (and RAID-6), respectively. Besides, our scheme also improves the endurance and reliability of SSD RAID compared to original elastic striping.
Auteurs: Yongkun Li;Biaobiao Shen;Yubiao Pan;Yinlong Xu;Zhipeng Li;John C. S. Lui;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 815 - 828
Editeur: IEEE
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» Wrinkled Single-Crystalline Germanium Nanomembranes for Stretchable Photodetectors
Résumé:
Germanium nanomembranes are suitable for flexible electronics, including high-mobility nonsilicon transistors, fast radio-frequency switches, microwave diodes, and high-performance photodetectors. In order to enhance the flexibility of the germanium-based devices, we present a strategy to integrate single-crystalline germanium nanomembranes into a wave-like wrinkled geometry with a uniform periodicity and amplitude on elastomeric substrates. Wrinkled single-crystalline germanium nanomembranes are realized with a reversible and large deformation up to 10%, and the stretchable metal–germanium–metal photodetectors have been demonstrated. Optoelectronic response studies reveal that the wrinkled germanium-based photodetectors exhibit enhanced efficiency of optoelectronic interactions compared with planar photodetectors using flat germanium nanomembranes. Furthermore, the wrinkled photodetectors reveal high response speed and stretchable capability of up to 8.56%. This paper may pave the way for the integration of germanium nanomembranes into the field of flexible/wearable optoelectronics.
Auteurs: Qinglei Guo;Yangfu Fang;Miao Zhang;Gaoshan Huang;Paul K. Chu;Yongfeng Mei;Zengfeng Di;Xi Wang;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 1985 - 1990
Editeur: IEEE
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» X-Duplex Relaying: Adaptive Antenna Configuration
Résumé:
We propose a joint transmission mode and transmit/receive (Tx/Rx) antenna configuration scheme referred to as X-duplex in the relay network with one source, one amplify-and-forward relay, and one destination. The relay is equipped with two antennas, each of which is capable of reception and transmission. In the proposed scheme, the relay adaptively selects its Tx and Rx antenna, operating in either full-duplex or half-duplex mode. The proposed scheme is based on minimizing the symbol error rate (SER) of the relay system. The asymptotic expressions of the cumulative distribution function for the end-to-end signal to interference plus noise ratio, average SER and diversity order are derived and validated by simulations. Results show the X-duplex scheme achieves additional spatial diversity, reduces the performance floor at high SNR, and improves the system performance.
Auteurs: Shuai Li;Mingxin Zhou;Jianjun Wu;Lingyang Song;Yonghui Li;Hongbin Li;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1083 - 1086
Editeur: IEEE
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» Young Professionals - Catching the Right Wave for Your Career
Résumé:
Advertisement, IEEE.
Auteurs: Katie Allen;Alex Zamora;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 75 - 76
Editeur: IEEE
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» ZapDroid: Managing Infrequently Used Applications on Smartphones
Résumé:
User surveys have shown that a typical user has over a 100 apps on his/her smartphone  [1] , but stops using many of them. We conduct a user study to identify such unused apps, which we call zombies, and show via experiments that zombie apps consume significant resources on a user’s smartphone and access his/her private information. We then design and build ZapDroid, which enables users to detect and silo zombie apps in an effective way to prevent their undesired activities. If and when the user wishes to resume using such an app, ZapDroid restores the app quickly and effectively. Our evaluations show that: (i) ZapDroid saves twice the energy from unwanted zombie app behaviors as compared to apps from the Play Store that kill background unwanted processes, and (ii) it effectively prevents zombie apps from using undesired permissions. In addition, ZapDroid is energy-efficient, consuming < 4 percent of the battery per day.
Auteurs: Indrajeet Singh;Srikanth V. Krishnamurthy;Harsha V. Madhyastha;Iulian Neamtiu;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1475 - 1489
Editeur: IEEE
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» [Conference Calendar]
Résumé:
Provides a notice of upcoming conference events of interest to practitioners and researchers.
Auteurs: Bernadette Bouchon-Meunier;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 05.-2017, volume: 12, issue:2, pages: 70 - 71
Editeur: IEEE
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