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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 05-2017 trié par par titre, page: 1
» A Self-Routing on-Chip Network
Résumé:
This paper introduces a new nonblocking self-routing network, called a multi-root binary tree, which may be used to interconnect the cores in multicore chips. The multi-root binary tree network differs from other binary tree-based networks in that the cores are placed at the roots rather than the leaves or the interior nodes of the trees. The self-routing property of a multi-root binary tree is built on the concept of replication and clustering. A new replication and clustering method, called the triangular shift pairing is given to connect the cores together over dedicated paths. It is shown that connecting cores in clusters requires at least n/2 columns of pairings for an n -core network in a grid layout model and triangular shift wiring method matches this lower bound. The replication and clustering concept leads to a simple self-routing scheme that pairs cores by decoding both unicast and multicast connection requests using math\rm{\lg} ;n -bit cluster address bits. In particular, it is established that cores can identify the cluster with which they pair with other cores using simple modulo addition of their own ids and addresses of the targeted cores in 2math\rm{\lg}; n single bit-decoding steps. It is also shown that, if connection requests are uniformly distributed among the cores then blocking due to target c nflicts can be avoided if cores serve connection requests at a small multiple of the frequencies with which they receive them.
Auteurs: A. Yavuz Oruç;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1229 - 1239
Editeur: IEEE
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» A Self-Wetting Paper Electrode for Ubiquitous Bio-Potential Monitoring
Résumé:
This paper aims to develop a flexible and cost-effective dry electrode with low and stable contact impedance. With these benefits, the electrode can be practically used in ubiquitous bio-potential monitoring with similar signal-to-noise ratio as commercial wet electrode. A self-wetting electrode is developed by the aid of moisture naturally created by skin under the electrode. It consists of a layer of ethylcellulose fiber paper coated with PEDOT/PSS (PCwPEDOT) and a thin layer of parylene. PCwPEOT, which has a large contact area composed of micro-scale fibers, is a 30- $mu text{m}$ flexible membrane that acts as the electrode material. A 3- $mu text{m}$ parylene bonding at the backside of PCwPEOT, as a high-performance vacuum membrane, can collect moisture or sweat naturally evaporating from the skin and store it in the PCwPEDOT layer. This design increases the humidity of skin, especially the water content in the corneum, acting as electrolyte containing ions, increases effective contact area between electrode and skin, and decreases the impedance of the electrode. With an environmentally friendly and cost-effective fabrication process, the 33- $mu text{m}$ thickness of electrode is light and flexible. It can be tailored to proper size according to the application. It achieves lower contact impedance compared with dry electrodes with a similar structure. Its recording performance is comparable to commercial patch electrode. The proposed electrode provides high-quality signals, and comfortable user experience in bio-potential recording. It is feasible for developing a long-term wearable system for bio-potential monitoring.
Auteurs: Xuhong Guo;Weihua Pei;Yijun Wang;Qi Gong;He Zhang;Xiao Xing;Yuxing Xie;Qiang Gui;Hongda Chen;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2654 - 2661
Editeur: IEEE
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» A Sentiment Analysis System to Improve Teaching and Learning
Résumé:
Natural language processing and machine learning can be applied to student feedback to help university administrators and teachers address problematic areas in teaching and learning. The proposed system analyzes student comments from both course surveys and online sources to identify sentiment polarity, the emotions expressed, and satisfaction versus dissatisfaction. A comparison with direct-assessment results demonstrates the system's reliability.
Auteurs: Sujata Rani;Parteek Kumar;
Apparue dans: Computer
Date publication: 05.-2017, volume: 50, issue:5, pages: 36 - 43
Editeur: IEEE
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» A Simple Picosecond Pulse Generator Based on a Pair of Step Recovery Diodes
Résumé:
A picosecond pulse generator based on a pair of step recovery diodes (SRDs) is proposed. This generator leverages the transient response of the SRD p-n junction, and provides pulsewidth tunability via a resistor. We first explain the operation principle of the device, by decomposing the pulse generation into different phases, and then demonstrate an experimental prototype with two different pulse values.
Auteurs: Lianfeng Zou;Shulabh Gupta;Christophe Caloz;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 467 - 469
Editeur: IEEE
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» A Source-Model Technique for Analysis of Waveguiding Across an Array of Arbitrary Smooth Cylinders Partially Buried in a Penetrable Substrate
Résumé:
A computational technique for modal analysis of an array of penetrable cylinders with smooth arbitrary cross section is described. The cylinders are partially buried between two penetrable half-space media, as may occur in fabricated device. Our suggested method is a rigorous full-wave frequency-domain source-model technique. The corner-like intersections of the cylinders with the substrate and superstrate are addressed with particular care, by intricately locating properly modulated fictitious sources, so that the rapid spatial variations of the fields can be effectively modeled. The spurious-free modal analysis scheme is sped up with an efficient serial mode-tracking scheme, which is based on the physical perturbation theory. The respective software tool is robust to the choice of materials, geometric parameters, and wavelength. Sample results are presented for circular and triangle-like cylinders. We demonstrate a red shift of the cut-off frequency of these potential waveguides as they are more deeply buried in a high refractive index medium, yet in general, the eigenmodes change rapidly but not necessarily monotonously as a function of the burial depth.
Auteurs: Dana Szafranek;Yehuda Leviatan;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2748 - 2753
Editeur: IEEE
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» A Space-Time RLS Algorithm for Adaptive Equalization: The Camera Communication Case
Résumé:
This paper presents a novel space-time recursive least-squares adaptive algorithm, which performs filter coefficients updates in space and postponed filtering in time. The algorithm is used for intersymbol interference suppression in optical camera communications, which is a subgroup of visible light communication systems. Optical camera communications uses image sensor receivers, as those available in smartphones, tablets, and laptops, to detect changes in light intensity in order to allow data transmission. The achievable data transmission rate of optical camera communication systems is nowadays constrained by the frame-per-second rate achieved by those devices, so that the spatial dimension, e.g., multiple-input multiple-output techniques, are typically exploited. Spatial intersymbol interference could arise and image blurring can be an issue especially when the link distance grows and/or when the receiver is in mobility. We present here a semiblind spatial fractionally spaced equalizer that uses a novel space-time recursive least-square adaptive algorithm to counteracts the blur introduced by the optical channel. Numerical results show how the bit error rate can be drastically reduced in both motion and out-of-focus blur scenarios.
Auteurs: Stefano Pergoloni;Mauro Biagi;Stefania Colonnese;Roberto Cusani;Gaetano Scarano;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1811 - 1820
Editeur: IEEE
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» A Sparsity-Based Variational Approach for the Restoration of SMOS Images From L1A Data
Résumé:
The Surface Moisture and Ocean Salinity (SMOS) mission senses ocean salinity and soil moisture by measuring Earth's brightness temperature using interferometry in the L-band. These interferometry measurements known as visibilities constitute the SMOS L1A data product. Despite the L-band being reserved for Earth observation, the presence of illegal emitters causes radio frequency interference (RFI) that masks the energy radiated from the Earth and strongly corrupts the acquired images. Therefore, the recovery of brightness temperature from corrupted data by image restoration techniques is of major interest. In this paper, we propose a variational model to recover superresolved, denoised brightness temperature maps by decomposing the images into two components: an image T that models the Earth's brightness temperature and an image O modeling the RFIs.
Auteurs: Javier Preciozzi;Andrés Almansa;Pablo Musé;Sylvain Durand;Ali Khazaal;Bernard Rougé;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2811 - 2826
Editeur: IEEE
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» A ST-CRF Map-Matching Method for Low-Frequency Floating Car Data
Résumé:
Integrating raw Global Position System (GPS) trajectories with a road network is often referred to as a map-matching problem. However, low-frequency trajectories (e.g., one GPS point for every 1–2 min) have raised many challenges to existing map-matching methods. In this paper, we propose a novel and global spatial–temporal map-matching method called spatial and temporal conditional random field (ST-CRF), which is based on insights relating to: 1) the spatial positioning accuracy of GPS points with the topological information of the underlying road network; 2) the spatial–temporal accessibility of a floating car; 3) the spatial distribution of the middle point between two consecutive GPS points; and 4) the consistency of the driving direction of a GPS trajectory. We construct a conditional random field model and identify the best matching path sequence from all candidate points. A series of experiments conducted for real environments using mass floating car data collected in Beijing and Shanghai shows that the ST-CRF method not only has better performance and robustness than other popular methods (e.g., point-line, ST-matching, and interactive voting-based map-matching methods) in low-frequency map matching but also solves the “label-bias” problem, which has long existed in the map matching of classical hidden Markov-based methods.
Auteurs: Xiliang Liu;Kang Liu;Mingxiao Li;Feng Lu;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1241 - 1254
Editeur: IEEE
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» A Stable Analytical Framework for Isometric Shape-from-Template by Surface Integration
Résumé:
Shape-from-Template (SfT) reconstructs the shape of a deforming surface from a single image, a 3D template and a deformation prior. For isometric deformations, this is a well-posed problem. However, previous methods which require no initialization break down when the perspective effects are small, which happens when the object is small or viewed from larger distances. That is, they do not handle all projection geometries. We propose stable SfT methods that accurately reconstruct the 3D shape for all projection geometries. We follow the existing approach of using first-order differential constraints and obtain local analytical solutions for depth and the first-order quantities: the depth-gradient or the surface normal. Previous methods use the depth solution directly to obtain the 3D shape. We prove that the depth solution is unstable when the projection geometry tends to affine, while the solution for the first-order quantities remain stable for all projection geometries. We therefore propose to solve SfT by first estimating the first-order quantities (either depth-gradient or surface normal) and integrating them to obtain shape. We validate our approach with extensive synthetic and real-world experiments and obtain significantly more accurate results compared to previous initialization-free methods. Our approach does not require any optimization, which makes it very fast.
Auteurs: Ajad Chhatkuli;Daniel Pizarro;Adrien Bartoli;Toby Collins;
Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence
Date publication: 05.-2017, volume: 39, issue:5, pages: 833 - 850
Editeur: IEEE
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» A State-Dependent Updating Period for Certified Real-Time Model Predictive Control
Résumé:
In this paper, a state-dependent control updating period strategy is proposed for use in interrupted implementation of real-time Model Predictive Control (MPC). The strategy can be used as soon as a certification bound is available for the underlying optimization algorithm. Moreover, a new fast-Gradient based certifiable algorithm is proposed with the associated certification bounds for convex generally constrained optimization problems.
Auteurs: Mazen Alamir;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2464 - 2469
Editeur: IEEE
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» A Study of Injection Locking in Dual-Band CMOS Frequency Dividers
Résumé:
We present a study of dual-band injection locking frequency dividers (ILFDs), based on a nonlinear analysis. We develop a quasi-normal model of these dividers suitable for applying the method of averaging, which allowed us to derive in a simple and expressive manner the first-approximation equations for the amplitudes and phases of the locked modes, both in transient and in steady state. The phase equations have the same form of the Adler’s equation, and represent the generalization of that well-known equation to higher-order frequency dividers. These equations allowed us to derive the locking ranges in a simple explicit form, useful for design purposes. The theoretical results are validated by Spice simulations, and by measurements on a circuit prototype.
Auteurs: Antonio Buonomo;Alessandro Lo Schiavo;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1225 - 1234
Editeur: IEEE
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» A Study of the Mesh Topology in a ZigBee Network for Home Automation Applications
Résumé:
Technological advances allowed in recent years the development of numerous applications and systems that improve people's lives in various sectors, especially the home automation. Already the wireless communication has become dominant in the data transmission segment to allow greater adaptability and flexibility in access to multiple devices among users, and networks based on wireless protocols (IEEE 802.11) widely used. However other protocols such as ZigBee (IEEE 802.15.4) appear quite attractive relative to price, power consumption, and reduced implementation of electronic projects. This study aims to evaluate the performance of the mesh topology operating modes in a ZigBee network. Results showed that there is a performance difference between the operation modes of the mesh topology. In the residential environment were carried out communication tests between the ZigBee network devices, where the results were acceptable to the tested environment. Distances and response times between the ZigBee network devices were within the minimum quality requirements for the operation of home automation project.
Auteurs: Carlos Alexandre Gouvea da Silva;Edson Leonardo dos Santos;Allan Christian Krainski Ferrari;Horacio Tertuliano dos Santos Filho;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 935 - 942
Editeur: IEEE
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» A Study on the Effects of Release Area on the Quality Factor of Contour-Mode Resonators by Laser Doppler Vibrometry
Résumé:
Through the use of a laser Doppler vibrometer, it is shown that a 31% variation in quality factor can occur due to the effect of undercutting of the device layers outside of the anchors of a 220-MHz aluminum nitride contour-mode resonator. This undercutting is a result of the isotropic etch process used to release the device from the substrate. This paper shows that the variation in $Q$ is a function of the release distance, $L$ , between the active region of the resonator and the edge of this released region. This paper also determined a design modification that eliminated this issue and achieved a $Q$ of 3048, which is independent of $L$ .
Auteurs: Brian Gibson;Kamala Qalandar;Cristian Cassella;Gianluca Piazza;Kimberly L. Foster;
Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Date publication: 05.-2017, volume: 64, issue:5, pages: 898 - 904
Editeur: IEEE
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» A Subthreshold Voltage Reference With Scalable Output Voltage for Low-Power IoT Systems
Résumé:
This paper presents a subthreshold voltage reference in which the output voltage is scalable depending on the number of stacked PMOS transistors. A key advantage is that its output voltage can be higher than that obtained with conventional low-power subthreshold voltage references. The proposed reference uses native NMOS transistors as a current source and develops a reference voltage by stacking one or more PMOS transistors. The temperature coefficient of the reference voltage is compensated by setting the size ratio of the native NMOS and stacked pMOS transistors to cancel temperature dependence of transistor threshold voltage and thermal voltage. Also, the transistor size is determined considering the trade-off between diode current between n-well and p-sub and process variation. Prototype chips are fabricated in a 0.18- $mu text{m}$ CMOS process. Measurement results from three wafers show $3sigma $ inaccuracy of ±1.0% from 0 °C to 100 °C after a single room-temperature trim. The proposed voltage reference achieves a line sensitivity of 0.31%/V and a power supply rejection of −41 dB while consuming 35 pW from 1.4 V at room temperature.
Auteurs: Inhee Lee;Dennis Sylvester;David Blaauw;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 05.-2017, volume: 52, issue:5, pages: 1443 - 1449
Editeur: IEEE
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» A Successful Approach to the 2016 RobotX Challenge
Résumé:
Discover how the University of Florida's team prepared for the most difficult collegiate-level robotic competition. The Web extra at https://youtu.be/ODmYL8SQcN8 showcases the development of the NaviGator Autonomous Maritime System for participation in the 2016 Maritime RobotX Challenge in Hawaii.
Auteurs: Andrew C. Gray;Eric M. Schwartz;
Apparue dans: Computer
Date publication: 05.-2017, volume: 50, issue:5, pages: 106 - 109
Editeur: IEEE
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» A Supervisory Power Management System for a Hybrid Microgrid With HESS
Résumé:
This paper proposes a supervisory power management system (PMS) for a grid interactive microgrid with a hybrid energy storage system. The key feature of the proposed PMS is reduced number of sensors required to implement the PMS. The PMS considers renewable power variation, grid availability, electricity pricing, and changes in local loads. It can detect the operating mode of system without measuring load currents and powers. A single-phase voltage source converter (VSC) transfers real power between dc grid and utility grid besides offering ancillary services such as harmonic mitigation, reactive power support, and unity power factor at the point of common coupling (PCC). In the proposed system, a better dc-link voltage regulation is achieved and the usage of supercapacitors reduces the current stress on the battery. The PMS also addresses extreme operating conditions such as load shedding, off-maximum power point tracking operation of photovoltaic, elimination of critical oscillation of hybrid energy storage systems power, islanded operation, and resynchronization with grid. The performance of the proposed PMS is verified by digital simulation and experimental studies.
Auteurs: Srikanth Kotra;Mahesh Kumar Mishra;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3640 - 3649
Editeur: IEEE
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» A Survey on the Coordination of Connected and Automated Vehicles at Intersections and Merging at Highway On-Ramps
Résumé:
Connected and automated vehicles (CAVs) have the potential to improve safety by reducing and mitigating traffic accidents. They can also provide opportunities to reduce transportation energy consumption and emissions by improving traffic flow. Vehicle communication with traffic structures and traffic lights can allow individual vehicles to optimize their operation and account for unpredictable changes. This paper summarizes the developments and the research trends in coordination with the CAVs that have been reported in the literature to date. Remaining challenges and potential future research directions are also discussed.
Auteurs: Jackeline Rios-Torres;Andreas A. Malikopoulos;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1066 - 1077
Editeur: IEEE
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» A System Concept for Online Calibration of Massive MIMO Transceiver Arrays for Communication and Localization
Résumé:
Massive multiple-input multiple-output (MIMO) techniques are being considered for the fifth generation (5G) mobile communication systems in order to deliver high multiplexing gain. However, hardware impairments like quadrature imbalance in mixers violate the requirement for channel reciprocity and may change, e.g., with temperature or while aging. In addition, advanced wireless localization techniques and the generation of predefined beam patterns require knowledge about all antenna phase center positions and the time and phase delay of all transmit and receive channels. Thus, an efficient online compensation method is needed that scales well for very large numbers of transceiver modules. We propose to extend the transmitter with a small measurement feature at the transmitter output based on one uncalibrated power detector per module as well as a single, external four-element backscatter array for the entire matrix. These enhancements facilitate a fast and efficient iterative calibration, which recognizes and mitigates all major error sources. Beside optimal communication throughput and energy efficiency, it thereby brings localization capabilities to mobile networks as an additional major benefit. For verification, a system of multiple cost-efficient 5.8-GHz massive MIMO transceivers with 150-MHz bandwidth and a backscatter array has been implemented. Measurement results demonstrate the capability of the proposed concept to efficiently compensate major error sources as well as its robustness.
Auteurs: Patrick Gröschel;Shahram Zarei;Christian Carlowitz;Melanie Lipka;Erik Sippel;Arslan Ali;Robert Weigel;Robert Schober;Martin Vossiek;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1735 - 1750
Editeur: IEEE
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» A Systematic Approach to Clustering Whole Trajectories of Mobile Objects in Road Networks
Résumé:
Most of mobile object trajectory clustering analysis to date has been focused on clustering the location points or sub-trajectories extracted from trajectory data. This paper presents TraceMob, a systematic approach to clustering whole trajectories of mobile objects traveling in road networks. TraceMob as a whole trajectory clustering framework has three unique features. First, we design a quality measure for the distance between two whole trajectories. By quality, we mean that the distance measure can capture the complex characteristics of trajectories as a whole including their varying lengths and their constrained movement in the road network space. Second, we develop an algorithm that transforms whole trajectories in a road network space into multidimensional data points in a euclidean space while preserving their relative distances in the transformed metric space. This transformation enables us to effectively shift the clustering task for whole mobile object trajectories in the complex road network space to the traditional clustering task for multidimensional data in a euclidean space. Third, we develop a cluster validation method for evaluating the clustering quality in both the transformed metric space and the road network space. Extensive experimental evaluation with trajectories generated on real road network maps of different cities shows that TraceMob produces higher quality clustering results and outperforms existing approaches by an order of magnitude.
Auteurs: Binh Han;Ling Liu;Edward Omiecinski;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 05.-2017, volume: 29, issue:5, pages: 936 - 949
Editeur: IEEE
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» A Therapeutic Wireless Capsule for Treatment of Gastrointestinal Haemorrhage by Balloon Tamponade Effect
Résumé:
Objective: Wireless capsule endoscope (WCE) is a revolutionary approach to diagnose small bowel pathologies. Currently available WCEs are mostly passive devices with image capturing function only, while on-going efforts have been placed on robotizing WCEs or to enhance them with therapeutic functions. In this paper, the authors present a novel inflatable WCE for haemostasis in the gastrointestinal (GI) tracts by balloon tamponade effect. Methods: The proposed wireless capsule consists of a balloon that can be inflated using the endothermic reaction of acid and base. When the balloon reached a precalculated pressure level, it is able to stop at a bleeding site in the bowel, and achieve haemostasis by tamponade effect. The prototype is 14 mm in diameter, with three sections of 13, 35, and 12 mm in length, respectively. The three sections are linked together with flexible joints and enclosed in a silicone balloon. The prototypes were tested in ex vivo porcine intestine models. Results: In the ten ex vivo trials conducted, the inflatable wireless capsule achieved average balloon pressure of 46.0 mmHg and withstood average maximum longitudinal pulling force at 1.46 N. An in vivo study was carried out as a proof-of-concept for treating bleeding in a porcine model. The proposed inflatable WCE succeeded in the animal test by controlling haemostasis within 5 min. No rebleeding was observed in the next 20 min. Conclusion: The results suggested that the inflatable capsule with a real-time bleeding detection algorithm can be implemented. Moreover, the proposed inflatable WCE prototype can achieve haemorrhage control in the lower GI. Significance: To our best knowledge, this is the first study that demonstrated the potential to treat GI haemorrhage by an inflatable WCE. The proposed capsule enables the development of a closed-loop system based on a body sensor network to provi- e early treatment of GI bleeding for p-medicine.
Auteurs: Billy H. K. Leung;Carmen C. Y. Poon;Ruikai Zhang;Yali Zheng;Cecilia K. W. Chan;Philip W. Y. Chiu;James Y. W. Lau;Joseph J. Y. Sung;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 1106 - 1114
Editeur: IEEE
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» A Thickness Measurement System for Metal Films Based on Eddy-Current Method With Phase Detection
Résumé:
This paper proposes a high-speed measurement system for the thickness of metal films based on the eddy-current method. Theoretical derivation shows the effects of film thickness on the impedance of the sensor coil. In a voltage division circuit, the thickness information is converted to the phase difference of two measured signals. The tangent value of the phase difference is proportional to thickness h, which is a result that has been verified theoretically and experimentally. The prototype used in this paper can cover a measurement range of 10 μm–0.5 mm for copper films, and can achieve a high measurement speed (up to excitation frequency) without a complex demodulation circuit. The measurement error caused by the temperature variation is roughly –0.2%/°C. The influence of external magnetic field on the prototype is also tested. The entire sensor size can be easily controlled in 50 × 50 × 30 mm3 as a handheld device. The instrument can meet many industrial requirements for both online measurement and postinspection.
Auteurs: Wei Li;Yang Ye;Kang Zhang;Zhihua Feng;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3940 - 3949
Editeur: IEEE
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» A Three-Year Feedback Study of a Remote Laboratory Used in Control Engineering Studies
Résumé:
This paper discusses the results of a feedback study for a remote laboratory used in the education of control engineering students. The goal is to show the effectiveness of the remote laboratory on examination results. To provide an overview, the two applications of the remote laboratory are addressed: 1) the Stewart platform, and 2) the quadruple water tank system. Combining both applications allows a broad spectrum of practical examples featuring challenging control aspects such as multiple-input–multiple-output control, decoupling, non-minimum phase systems, open-loop unstable systems, and PID control design. The remote laboratory feedback study was performed using a five-point Likert-type scale survey to elicit the students’ level of satisfaction with the laboratory. Three years of student examination results were also studied to compare performance before and after integrating the remote laboratory. In the first of these years there was no use of the remote laboratory. In the second year, the remote laboratory was introduced on a voluntary basis, and in the third year the remote laboratory was obligatory. Student feedback indicates that the remote laboratory needs further development to counter its limitations. A major conclusion of the survey was that there is keen interest in the remote laboratory to provide practical experience in the training of a control engineer. It can be concluded that the remote laboratory has a positive effect on student examination results.
Auteurs: Amélie Chevalier;Cosmin Copot;Clara Ionescu;Robin De Keyser;
Apparue dans: IEEE Transactions on Education
Date publication: 05.-2017, volume: 60, issue:2, pages: 127 - 133
Editeur: IEEE
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» A Time-Harmonic Inverse Design of Uniplanar RF Coil for Unilateral NMR Sensors
Résumé:
A time-harmonic inverse method was employed to design a uniplanar radio-frequency (RF) coil for unilateral nuclear magnetic resonance (UNMR) sensors to improve coil sensitivity and signal-to-noise ratio. In the design, an ideal current density was calculated on a planar surface and generated a specified magnetic field, which was perpendicular and correlated with a given in-homogenous main magnetic field with a constant linear static gradient in the region of interest. The basic functions of the current density were represented by a Fourier series, and a simple matrix inversion approach was utilized to obtain the corresponding current coefficients. Stream function techniques were then used to implement this theoretical current density into an RF coil. A uniplanar RF coil for a UNMR sensor was designed and constructed, and the results were presented.
Auteurs: Zhonghua He;Wei He;Jiamin Wu;Zheng Xu;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2696 - 2702
Editeur: IEEE
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» A Traceback Attack on Freenet
Résumé:
Freenet is a popular peer to peer anonymous content-sharing network, with the objective to provide the anonymity of both content publishers and retrievers. Despite more than a decade of active development and deployment and the adoption of well-established cryptographic algorithms in Freenet, it remains unanswered how well the anonymity objective of the initial Freenet design has been met. In this paper we develop a traceback attack on Freenet, and show that the originating machine of a content request message in Freenet can be identified; that is, the anonymity of a content retriever can be broken, even if a single request message has been issued by the retriever. We present the design of the traceback attack, and perform both experimental and simulation studies to confirm the feasibility and effectiveness of the attack. For example, with randomly chosen content requesters (and random contents stored in the Freenet testbed), Emulab-based experiments show that, for $24$ to $43$ percent of the content request messages, we can identify their originating machines. We also briefly discuss potential solutions to address the developed traceback attack. Despite being developed specifically on Freenet, the basic principles of the traceback attack and solutions have important security implications for similar anonymous content-sharing systems.
Auteurs: Guanyu Tian;Zhenhai Duan;Todd Baumeister;Yingfei Dong;
Apparue dans: IEEE Transactions on Dependable and Secure Computing
Date publication: 05.-2017, volume: 14, issue:3, pages: 294 - 307
Editeur: IEEE
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» A Triband Low-Profile High-Gain Planar Antenna Using Fabry–Perot Cavity
Résumé:
A triband antenna with high gain and low profile is proposed. This antenna is based on the concept of Fabry–Perot cavity antenna (FPCA) and three resonances are obtained by employing two frequency selective surface (FSS) layers. Two FSS layers lead to two resonant frequencies by making each FSS layer satisfy the resonant condition of Fabry–Perot cavity. The third resonant frequency is obtained by exploiting the combined effects of the two FSS layers together. The operating principle of this proposed antenna is explained and the achievable frequency range is investigated. It is shown that the proposed method enables all three resonant frequencies to be independently tuned within certain frequency range. Because of the 0° reflection phase of the combined-FSSs, the present antenna has a low profile. To verify the design concept, one C-/X-/Ku-band FPCA is designed, fabricated and tested. Experimental results agree well with the simulated results. High gain with good impedance matching in three bands is obtained, which reaches a peak gain of 13.4 dBi at 5.2 GHz, 18.9 dBi at 9.7 GHz, and 20 dBi at 14.6 GHz. The overall height of the proposed antenna is approximately 0.36 wavelength at its lowest operating frequency.
Auteurs: Fan Qin;Steven Gao;Qi Luo;Gao Wei;Jiadong Xu;Jianzhou Li;Changying Wu;Chao Gu;Chunxu Mao;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2683 - 2688
Editeur: IEEE
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» A Triple Band Frequency Selective Surface Design for GSM Systems by Utilizing a Novel Synthetic Resonator
Résumé:
In this communication, a novel triple band frequency selective surface (FSS) designed for Global System for Mobile Communications (GSMs) frequency bands is presented. Unit cell of the proposed FSS consists of one rectangular-shaped resonator designed for 942 MHz and one synthetic resonator designed for both of 1842 and 2142 MHz frequencies. A novel technique is introduced to design a synthetic resonator in which two loop-shaped resonators intersect to each other resulting a unique resonator operating at two frequencies. The proposed design has the advantages of separating two very closely spaced frequency bands as in GSM systems with a narrow notch between the two frequencies of 1842 and 2142 MHz. Furthermore, a very low-frequency response sensitivity to the oblique incidence angles is achieved by using a miniaturized single synthetic resonator for the two frequencies in a single layer. Good agreement is observed between the measured and simulated results. A minimum of 20-dB attenuation for the transmission coefficient is achieved in all downlink frequency ranges of GSM system with a good stability against the oblique angle of incidence for both transverse-electric and transverse-magnetic polarizations.
Auteurs: M. Kartal;J. J. Golezani;B. Doken;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2724 - 2727
Editeur: IEEE
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» A Unified Detail-Preserving Liquid Simulation by Two-Phase Lattice Boltzmann Modeling
Résumé:
Traditional methods in graphics to simulate liquid-air dynamics under different scenarios usually employ separate approaches with sophisticated interface tracking/reconstruction techniques. In this paper, we propose a novel unified approach which is easy and effective to produce a variety of liquid-air interface phenomena. These phenomena, such as complex surface splashes, bubble interactions, as well as surface tension effects, can co-exist in one single simulation, and are created within the same computational framework. Such a framework is unique in that it is free from any complicated interface tracking/reconstruction procedures. Our approach is developed from the two-phase lattice Boltzmann method with the mean field model, which provides a unified framework for interface dynamics but is numerically unstable under turbulent conditions. Considering the drawbacks of the existing approaches, we propose techniques to suppress oscillations for significant stability enhancement, as well as derive a new subgrid-scale model to further improve stability, faithfully preserving liquid-air interface details without excessive diffusion by taking into account the density variation. The whole framework is highly parallel, enabling very efficient implementation. Comparisons with the related approaches show superiority on stable simulations with detail preservation and multiphase phenomena simultaneously involved. A set of animation results demonstrate the effectiveness of our method.
Auteurs: Yulong Guo;Xiaopei Liu;Xuemiao Xu;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1479 - 1491
Editeur: IEEE
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» A Vehicle Routing Problem Solved Through Some Metaheuristics Procedures: A Case Study
Résumé:
This study presents a Vehicle Routing Problem solved through some metaheuristics procedures. A two-phase methodology was used for that: 1) defining clusters of demand points to be served, as a Facilities Location Problem (FLP); and 2) defining routes to be developed within each cluster, as a Traveling Salesman Problem Asymmetric (TSPA). For a clearer understanding, the methodology was applied to a fast transportation company, referred here as ABC, located in the district Cidade Industrial of Curitiba (CIC), in Curitiba city, in Parana State, Brazil. The metaheuristics Simulated Annealing (SA), Tabu Search (TS) and a Hybrid Algorithm (HA) were used in the first phase (FLP) and also in the second phase (TSPA). Two scenarios were evaluated, with variations of the group number. In the first scenario, the goal was to form five groups of demand points, in order to compare with the company real situation (actual scenario). In the second scenario, the goal was to form three clusters. BT and SA metaheuristics presented the best results for the 1st. and 2nd. scenarios.
Auteurs: Julio Cesar Ferreira;Maria Teresinha Arns Steiner;Mariana Siqueira Guersola;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 943 - 949
Editeur: IEEE
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» A Very-Low-Frequency Electromagnetic Inductive Sensor System for Workpiece Recognition Using the Magnetic Polarizability Tensor
Résumé:
The automatic recognition of a metal component or workpiece currently relies on optical techniques and image matching. It is not possible to distinguish workpieces with different materials. In this paper, a novel electromagnetic inductive sensor array similar to those used in the electromagnetic tomography has been designed to address this problem. Furthermore, instead of reconstructing the full magnetic polarizability tensor, we have proposed a partial tensor approach, which shows that a 2-D tensor is capable of distinguishing the material difference and recognising the geometric dominance of workpieces with experimental data. In addition, it has been found that the phase of the tensor is strongly linked to the materials properties while the magnitude of the tensor eigenvalues implies the basic geometry of workpiece.
Auteurs: Yang Tao;Wuliang Yin;Wenbo Zhang;Yifei Zhao;Christos Ktistis;Anthony J. Peyton;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2703 - 2712
Editeur: IEEE
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» A Wearable Inertial Pedestrian Navigation System With Quaternion-Based Extended Kalman Filter for Pedestrian Localization
Résumé:
This paper presents a wearable inertial pedestrian navigation system and its associated pedestrian trajectory reconstruction algorithm for reconstructing pedestrian walking trajectories in indoor and outdoor environments. The proposed wearable inertial pedestrian navigation system is constructed by integrating a triaxial accelerometer, a triaxial gyroscope, a triaxial magnetometer, a microcontroller, and a Bluetooth wireless transmission module. Users wear the system on foot while walking in indoor and outdoor environments at normal speed without any external positioning techniques. During walking movement, the measured inertial signals generated from walking movements are transmitted to a computer via the wireless module. Based on the foot-mounted inertial pedestrian navigation system, a pedestrian trajectory reconstruction algorithm composed of the procedures of inertial signal acquisition, signal preprocessing, trajectory reconstruction, and trajectory height estimation has been developed to reconstruct floor walking and stair climbing trajectories. In order to minimize the cumulative error of the inertial signals, we have utilized a sensor fusion technique based on a double-stage quaternion-based extended Kalman filter to fuse acceleration, angular velocity, and magnetic signals. Experimental results have successfully validated the effectiveness of the proposed wearable inertial pedestrian navigation system and its associated pedestrian trajectory reconstruction algorithm.
Auteurs: Yu-Liang Hsu;Jeen-Shing Wang;Che-Wei Chang;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3193 - 3206
Editeur: IEEE
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» A Web Services Discovery Approach Based on Mining Underlying Interface Semantics
Résumé:
In recent years, Web service discovery has been a hot research topic. In this paper, we propose a novel Web services discovery approach, which can mine the underlying semantic structures of interaction interface parameters to help users find and employ Web services, and can match interfaces with high precision when the parameters of those interfaces contain meaningful synonyms, abbreviations, and combinations of disordered fragments. Our approach is based on mining the underlying semantics. First, we propose a conceptual Web services description model in which we include the type path for the interaction interface parameters in addition to the traditional text description. Then, based on this description model, we mine the underlying semantics of the interaction interface to create index libraries by clustering interaction interface names and fragments under the supervision of co-occurrence probability. This index library can help provide a high-efficiency interface that can match not only synonyms but also abbreviations and fragment combinations. Finally, we propose a Web service Operations Discovery algorithm (OpD). The OpD discovery results include two types of Web services: services with “Single” operations and services with “Composite” operations. The experimental evaluation shows that our approach performs better than other Web service discovery methods in terms of both discovery time and precision/ recall rate.
Auteurs: Bo Cheng;Shuai Zhao;Changbao Li;Junliang Chen;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 05.-2017, volume: 29, issue:5, pages: 950 - 962
Editeur: IEEE
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» A Wideband Contactless and Bondwire-Free MMIC to Waveguide Transition
Résumé:
A contactless transition from a high-permittivity microstrip line ( $epsilon _{r}=9.9$ ) to an air-filled waveguide (WG) has been impedance-matched over a large simulated relative bandwidth of 38% ( $W$ -band, 75–110 GHz). The transition couples the electromagnetic fields directly from the Monolithic Microwave Integrated Circuit (MMIC’s) microstrip line via an Substrate Integrated Waveguide and an off-chip stub section to a ridge WG section. The novel structure is low loss and suits pick-and-place assembly techniques of mm-wave MMICs inside metal WGs. The design process is detailed and manufacturing tolerances of the alumina prototype printed circuit board are discussed. The measured back-to-back structure retains an appreciable insertion loss smaller than 0.8 dB for a single transition and a fractional bandwidth of 28% (72–95 GHz) over which the return loss is greater than 10 dB.
Auteurs: Alhassan Aljarosha;Ashraf Uz Zaman;Rob Maaskant;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 437 - 439
Editeur: IEEE
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» A Wideband Differentially Fed Dual-Polarized Antenna with Stable Radiation Pattern for Base Stations
Résumé:
A new wideband differentially fed dual-polarized antenna with stable radiation pattern for base stations is proposed and studied. A cross-shaped feeding structure is specially designed to fit the differentially fed scheme and four parasitic loop elements are employed to achieve a wide impedance bandwidth. A stable antenna gain and a stable radiation pattern are realized by using a rectangular cavity-shaped reflector instead of a planar one. A detailed parametric study was performed to optimize the antenna’s performances. After that, a prototype was fabricated and tested. Measured results show that the antenna achieves a wide impedance bandwidth of 52% with differential standing-wave ratio <1.5 from 1.7 to 2.9 GHz and a high differential port-to-port isolation of better than 26.3 dB within the operating frequency bandwidth. A stable antenna gain ( $approx 8$ dBi) and a stable radiation pattern with 3-dB beamwidth of 65° ±5° were also found over the operating frequencies. Moreover, the proposed antenna can be easily built by using printed circuit board fabrication technique due to its compact and planar structure.
Auteurs: Ding-Liang Wen;Dong-Ze Zheng;Qing-Xin Chu;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2248 - 2255
Editeur: IEEE
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» A Wideband Fully Integrated Software-Defined Transceiver for FDD and TDD Operation
Résumé:
Although there is much active research on software-defined radios (SDRs) with receive (RX) or transmit (TX) functionality, little work has been done on SDR transceivers supporting frequency division duplex (FDD). In this paper, we present a new circuit concept in which a distributed TX circuit cancels the transmitted signal at a reverse RX port through destructive interference while adding signal constructively at a forward TX port. We pair the distributed transmitter with a receiver-tracking PA degeneration technique to suppress the injected noise from TX circuits in the RX band. The system does not require off-chip filters or circulators, but still achieves both SDR flexibility and both FDD and time division duplex function. Measurements from the transceiver implemented in 65-nm CMOS show a frequency tuning range of 0.3–1.6 GHz with TX–RX isolation >23 dB and transmitted power up to 19 dBm.
Auteurs: Hazal Yüksel;Dong Yang;Zachariah Boynton;Changhyuk Lee;Thomas Tapen;Alyosha Molnar;Alyssa Apsel;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 05.-2017, volume: 52, issue:5, pages: 1274 - 1285
Editeur: IEEE
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» A Wideband Noise-Canceling CMOS LNA With Enhanced Linearity by Using Complementary nMOS and pMOS Configurations
Résumé:
A complementary noise-canceling CMOS low-noise amplifier (LNA) with enhanced linearity is proposed. An active shunt feedback input stage offers input matching, while extended input matching bandwidth is acquired by a $pi$ -type matching network. The intrinsic noise cancellation mechanism maintains acceptable noise figure (NF) with reduced power consumption due to the current reuse principle. Multiple complementary nMOS and pMOS configurations commonly restrain nonlinear components in individual stage of the LNA. Complementary multigated transistor architecture is further employed to nullify the third-order distortion of noise-canceling stage and compensate the second-order nonlinearity of that. High third-order input intercept point (IIP3) is thus obtained, while the second-order input intercept point (IIP2) is guaranteed by differential operation. Implemented in a 0.18- $mu text{m}$ CMOS process, the experimental results show that the proposed LNA provides a maximum gain of 17.5 dB and an input 1-dB compression point (IP1 dB) of −3 dBm. An NF of 2.9–3.5 dB and an IIP3 of 10.6–14.3 dBm are obtained from 0.1 to 2 GHz, respectively. The circuit core only draws 9.7 mA from a 2.2 V supply.
Auteurs: Benqing Guo;Jun Chen;Lei Li;Haiyan Jin;Guoning Yang;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 05.-2017, volume: 52, issue:5, pages: 1331 - 1344
Editeur: IEEE
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» Abstracted Random Mediums for Electromagnetic Hotspot Observation in Finite-Difference Time-Domain Simulation
Résumé:
Microwave excitation of energetic materials can remotely incite ignition and deflagration. While this has been experimentally observed, the underlying principles are not well understood due to the complexity of analytical solutions. Further complicating understanding is the sensitivity of the effect to geometry and the difficulty of creating simulation environments representative of realistic materials. Manageable analysis requires abstractions, and here abstractions ranging from regularly arranged spheres and cubes to randomly arranged spheres, cubes, and arbitrarily shaped crystals are examined. The randomly arranged cube model provides acceptable prediction of thermal and peak electric field hotspots while having manageable computational complexity. The hotspots resulting from multiple subwavelength scattering occur inside the body of the energetic material and are localized in time and space having spans that are a few percent or less of the period and wavelength of pulsed electromagnetic excitation.
Auteurs: Michael Chen;Michael B. Steer;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1873 - 1879
Editeur: IEEE
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» Accumulated Chemical Adsorption Phenomenon of H2 on MOX Gas Sensor Under Temperature Programmed Cooling
Résumé:
For improving the sensitivity of MOX gas sensor, one of the effective methods is to increase the chemical adsorption of gas on the surface. This paper focused on the effect of temperature programmed cooling on the adsorption accumulation of the gas owning one chemical adsorption state. Herein, the experiments of resistance response test, work function test, and the theoretical simulation were conducted to investigate the chemical adsorption of H+ on MOX gas sensor. Compared with the constant temperature test, the resistance response and the work function change were both significantly increased for H2 detection in oxygen-free environment under temperature programmed cooling. Furthermore, the process of temperature programmed cooling was theoretically simulated based on the Langmuir adsorption model. The accumulated chemical adsorption phenomenon was revealed by the simulation. In brief, this discovery opens a way for the sensitivity improvement of MOX gas sensor.
Auteurs: Zhenghao Mao;Tao Lei;Yuhui He;Ziming Cai;Ya Xiong;Shunping Zhang;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2784 - 2791
Editeur: IEEE
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» Accurate and Standardized Coronary Wave Intensity Analysis
Résumé:
Objective: Coronary wave intensity analysis (cWIA) has increasingly been applied in the clinical research setting to distinguish between the proximal and distal mechanical influences on coronary blood flow. Recently, a cWIA-derived clinical index demonstrated prognostic value in predicting functional recovery post-myocardial infarction. Nevertheless, the known operator dependence of the cWIA metrics currently hampers its routine application in clinical practice. Specifically, it was recently demonstrated that the cWIA metrics are highly dependent on the chosen Savitzky–Golay filter parameters used to smooth the acquired traces. Therefore, a novel method to make cWIA standardized and automatic was proposed and evaluated in vivo. Methods: The novel approach combines an adaptive Savitzky–Golay filter with high-order central finite differencing after ensemble-averaging the acquired waveforms. Its accuracy was assessed using in vivo human data. The proposed approach was then modified to automatically perform beatwise cWIA. Finally, the feasibility (accuracy and robustness) of the method was evaluated. Results: The automatic cWIA algorithm provided satisfactory accuracy under a wide range of noise scenarios ($leq$ 10% and $leq$ 20% error in the estimation of wave areas and peaks, respectively). These results were confirmed when beat-by-beat cWIA was performed. Conclusion: An accurate, standardized, and automated cWIA was developed. Moreover, the feasibility of beatwise cWIA was demonstrated for the first time. Significance: The proposed algorithm provides practitioners with a standardized technique that could broaden the application of - WIA in the clinical practice as well as enabling multicenter trials. Furthermore, the demonstrated potential of beatwise cWIA opens the possibility of investigating the coronary physiology in real time.
Auteurs: Simone Rivolo;Tiffany Patterson;Kaleab N. Asrress;Michael Marber;Simon Redwood;Nicolas P. Smith;Jack Lee;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 1187 - 1196
Editeur: IEEE
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» Accurate Equivalent-Circuit Descriptions of Thin Glide-Symmetric Corrugated Metasurfaces
Résumé:
Thin artificial surfaces that act as high frequency bandgap structures have been recently studied for the design of gap waveguides, hard surfaces, and planar lenses. Here, we propose a circuit-based method to analyze glide-symmetric corrugated metasurfaces that are embedded in a thin parallel plate waveguide. Our closed-form solution is based on rigorous analytical derivations. It achieves remarkable agreement with full-wave solvers, even when the waveguide thickness is extremely thin. In contrast, classical homogenization approaches are shown to be inaccurate for thin waveguides due to the interaction of higher order Floquet modes between the surfaces. Numerical results validate our theoretical analysis and show the utility of the proposed method.
Auteurs: Guido Valerio;Zvonimir Sipus;Anthony Grbic;Oscar Quevedo-Teruel;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2695 - 2700
Editeur: IEEE
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» Accurate Object Localization in Remote Sensing Images Based on Convolutional Neural Networks
Résumé:
In this paper, we focus on tackling the problem of automatic accurate localization of detected objects in high-resolution remote sensing images. The two major problems for object localization in remote sensing images caused by the complex context information such images contain are achieving generalizability of the features used to describe objects and achieving accurate object locations. To address these challenges, we propose a new object localization framework, which can be divided into three processes: region proposal, classification, and accurate object localization process. First, a region proposal method is used to generate candidate regions with the aim of detecting all objects of interest within these images. Then, generic image features from a local image corresponding to each region proposal are extracted by a combination model of 2-D reduction convolutional neural networks (CNNs). Finally, to improve the location accuracy, we propose an unsupervised score-based bounding box regression (USB-BBR) algorithm, combined with a nonmaximum suppression algorithm to optimize the bounding boxes of regions that detected as objects. Experiments show that the dimension-reduction model performs better than the retrained and fine-tuned models and the detection precision of the combined CNN model is much higher than that of any single model. Also our proposed USB-BBR algorithm can more accurately locate objects within an image. Compared with traditional features extraction methods, such as elliptic Fourier transform-based histogram of oriented gradients and local binary pattern histogram Fourier, our proposed localization framework shows robustness when dealing with different complex backgrounds.
Auteurs: Yang Long;Yiping Gong;Zhifeng Xiao;Qing Liu;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2486 - 2498
Editeur: IEEE
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» Accurate Spectral Testing With Arbitrary Noncoherency in Sampling and Simultaneous Drifts in Amplitude and Frequency
Résumé:
Accurate spectral testing plays a crucial role in modern high-precision analog-to-digital converters’ (ADCs’) evaluation process. One of the challenges is to be able to cost-effectively test the continually higher resolution ADCs accurately. Due to its stringent test requirement, the standard test method for ADCs can be difficult to implement with low cost. This paper proposes an algorithm that relaxes the requirements of precise control over source amplitude and frequency, and of the need to achieve coherent sampling. The algorithm divides the output data into segments, and estimates drift fundamental via Newton iteration. By removing the estimated drift fundamental and replacing with a coherent, nondrift fundamental in time domain, accurate spectral results can be achieved. Various simulation results have validated the accuracy of the proposed algorithm. The proposed algorithm is capable of tolerating various test condition variations such as any-level of noncoherency, various input frequency range and different numbers of segmentations. In addition, several measurement results from different ADCs have verified the accuracy of the proposed algorithm, which is able to accurately obtain spectral performance of an 18 b high-resolution ADC. Such algorithm relaxes the standard test requirement such as precise control over source frequency and amplitude, which dramatically reduces the test setup complexity and cost.
Auteurs: Yuming Zhuang;Li Xu;Degang Chen;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 1002 - 1012
Editeur: IEEE
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» Achieving Resilience at Distribution Level: Learning from Isolated Community Microgrids
Résumé:
Increasing power system resilience at the distribution level is crucial due to the negative social impact of blackouts, as the undesired consequences get worse the longer the system restoration takes. Statistical records demonstrate that system recovery times after high-impact, low-probability events (e.g., earthquakes, tsunamis, and floods) are often faster for generation and transmission segments than for the distribution system. During the 2010 Chilean earthquake (8.8 Mw on the Richter scale), for example, the distribution system in the most affected area (almost 1.1 million customers) was not totally back in service until two weeks after the first major seismic event. In contrast, the transmission system rapidly recovered, with most of the bulk system buses re-energized by the end of the first day and the remainder during the second day. Additional installed generation capacity and repairing minor damage to most of the affected generation plants allowed for the recovery of most of the supply within a few days. Only 6.1% of the installed generation capacity required major repairs (which took up to six months to complete).
Auteurs: Guillermo Jiménez-Estévez;Alejandro Navarro-Espinosa;Rodrigo Palma-Behnke;Luigi Lanuzza;Nicolás Velázquez;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 05.-2017, volume: 15, issue:3, pages: 64 - 73
Editeur: IEEE
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» Acoustic Flow-Based Control of a Mobile Platform Using a 3D Sonar Sensor
Résumé:
Moving a sensor through its environment creates signature time variations of the sensor’s readings often referred to as flow cues. We analyze the acoustic flow field generated by a sonar sensor, capable of imaging the full frontal hemisphere, mounted on a mobile platform. We show how the cues derived from this acoustic flow field can be used directly in a layered control strategy, which supports a robotic platform to perform a set of motion primitives, such as obstacle avoidance, corridor following, and negotiating corners and T-junctions. The programmable nature of the spatial sampling pattern of the sonar allows efficient support of the varying information requirements of the different motion primitives. The proposed control strategy is first validated in a simulated environment and subsequently transferred to a real mobile robot. We present simulated and experimental results on the controller’s performance while executing the different motion primitives. The results further show that the proposed control strategy can easily integrate minimal steering commands given by a user (electric wheelchair application) or by a high-level navigation module (autonomous simultaneous localization and mapping (SLAM) applications).
Auteurs: Jan Steckel;Herbert Peremans;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3131 - 3141
Editeur: IEEE
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» Active Rehabilitation Exercises With a Parallel Structure Ankle Rehabilitation Prototype
Résumé:
In this paper the implementation of impedance controllers to develop active rehabilitation exercises are presented. For which it is used a parallel structure ankle rehabilitation prototype with a mechanism of the type 2-RRSP (two closed kinematic chains and consisting of joints: revolute-revolute-sphere in slot- fixed post with sphere). Free software is used to develop the computer programs associated with rehabilitation exercises. The results of active rehabilitation exercises are reported, wich involves the effect of resistance from the rehabilitation prototype to the user operation: low, medium and high opposition effects are considered.
Auteurs: Wilberth Melchor Alcocer Rosado;Andres Blanco Ortega;Luis Gerardo Vela Valdes;Jose Ruiz Ascencio;Carlos Daniel Garcia Beltran;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 786 - 794
Editeur: IEEE
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» Active Three-Way Circulator Using Transistor Feedback Network
Résumé:
This letter presents an active three-way circulator with both theoretical analyzes and experimental verifications. The conventional active circulators have their limitations on power handling and noise figure (NF), however, this proposed structure maintains both performances, which is formed by three 2-port transistor feedback networks (TFNs). This TFN is formed by an FET together with a feedback inductor. Experimental results show that this circulator achieves the isolation more than 35 dB, the insertion of around 2 dB, and the return losses better than 10 dB at each port at 1.8 GHz. The output power is linearly proportional to the power operation and the NF is around 5 dB. This compact structure, therefore, is suitable for use in the transmit/receive front end with a sufficient isolation, power handling, and NF for time division duplex operation.
Auteurs: Steve W. Y. Mung;Wing Shing Chan;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 476 - 478
Editeur: IEEE
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» Adaptive Control via Extremum Seeking: Global Stabilization and Consistency of Parameter Estimates
Résumé:
We propose an extremum seeking (ES) based algorithm for reference tracking and stabilization of unstable discrete-time systems with unknown control directions. The probing signal is a martingale difference sequence (m.d.s.) with a vanishing variance. It is proved that almost surely (a.s.) the input and output signals are uniformly bounded, and the tracking error converges to zero. It is also shown that (a.s.) the parameter estimates converge toward their true values. This shows that the proposed algorithm can also perform identification of open-loop unstable systems with unknown control directions.
Auteurs: Miloje S. Radenkovic;Miroslav Krstic;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2350 - 2359
Editeur: IEEE
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» Adaptive Control With Exponential Regulation in the Absence of Persistent Excitation
Résumé:
With set point regulation being the most common goal in control engineering, persistence of excitation (PE) is generically absent in adaptive control applications. In the absence of PE, not only is the parameter estimate not guaranteed to converge to the true value, but the state is regulated to the set point at a rate that is not necessarily exponential. In this technical note we introduce a strategy that employs time-varying adaptation gains (as well as time-varying control gains, when appropriate) and achieves exponential regulation of the plant state, with an exponential rate that is uniform in the initial condition. This idea fundamentally differs from exponential stability results achieved in the presence of PE because we make the gains (rather than reference signals) time-varying, i.e., we use time-varying tools in a multiplicative (rather than in an additive) fashion. We provide full state feedback results for general classes of nonlinear and linear systems and establish global uniform stability, exponential regulation of the plant state, boundedness of the control input and the update rate, and the asymptotic constancy (but not convergence to the true value) of the parameter estimate.
Auteurs: Yongduan Song;Kai Zhao;Miroslav Krstic;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2589 - 2596
Editeur: IEEE
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» Adaptive Fuzzy Control System for a Squirrel Cage Induction Motor
Résumé:
A fuzzy adaptive method is designed and implemented in order to improve the response of a scalar fuzzy control system for the speed of an induction motor. The adaptive method determines the set of output membership functions used in the difuzzification process of a typical fuzzy rule based control system. The universe, domain and distribution of the controller's output membership functions are defined at the beginning of every control cycle, thus having a dynamic generation of the set of output membership functions. In this paper, this method is applied to an induction motor in order to control its speed. The experimental results are compared to those obtained with a non-adaptive fuzzy controller, showing an improvement in torque, stator currents and voltages as well as some dynamic parameters such as steady state ripple.
Auteurs: Luis Antonio Mier Quiroga;Jorge Samuel Benitez Read;Regulo Lopez Callejas;Jose Armando Segovia de los Rios;Rosendo Pena Eguiluz;Francisco Javier Jimenez Ramirez;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 795 - 805
Editeur: IEEE
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» Adaptive Input Design for LTI Systems
Résumé:
Optimal input design for parameter estimation has obtained extensive coverage in the past. A key problem here is that the optimal input depends on some unknown system parameters that are to be identified. Adaptive design is one of the fundamental routes to handle this problem. Although there exist a rich collection of results on this problem, there are few results that address dynamical systems. This paper presents sufficient conditions for convergence/consistency and asymptotic optimality for a class of adaptive systems consisting of a recursive prediction error estimator and an input generator depending on the time-varying parameter estimates. The results apply to a general family of single input single output linear time-invariant systems. An important application is adaptive input design for which the results imply that, asymptotically in the sample size, the adaptive scheme recovers the same accuracy as the off-line prediction error method that uses data from an experiment where perfect knowledge of the system has been used to design an optimal input spectrum.
Auteurs: László Gerencsér;Håkan Hjalmarsson;Lirong Huang;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2390 - 2405
Editeur: IEEE
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» Adaptive Interval Type-2 Fuzzy Logic Control for PMSM Drives With a Modified Reference Frame
Résumé:
In this paper, an adaptive interval type-2 fuzzy logic control scheme is proposed for high-performance permanent magnet synchronous machine drives. This strategy combines the power of type-2 fuzzy logic systems with the adaptive control theory to achieve accurate tracking and robustness to higher uncertainties. Unlike other controllers, the proposed strategy does not require electrical transducers and hence, no explicit currents loop regulation is needed, which yields a simplified control scheme. But, this limits the machine's operation range since it results in a higher energy consumption. Therefore, a modified reference frame is also proposed in this paper to decrease the machine's consumption. To better assess the performance of the new reference frame, comparison against its original counterpart is carried-out under the same conditions. Moreover, the stability of the closed-loop control scheme is guaranteed by a Lyapunov theorem. Simulation and experimental results for numerous situations highlight the effectiveness of the proposed controller in standstill, transient, and steady-state conditions.
Auteurs: Hicham Chaoui;Mehdy Khayamy;Abdullah Abdulaziz Aljarboua;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3786 - 3797
Editeur: IEEE
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» Adaptive Locally Linear Embedding for Node Localization in Sensor Networks
Résumé:
Received signal strength indicator (RSSI) gives a rough initial measure of the inter-node distances at low cost without the need of additional equipment or complexity. This necessitates the need for a mechanism to obtain accurate node locations from the noisy RSSI distance estimates. In this paper, a non-linear manifold learning technique, adaptive locally linear embedding (ALLE), is proposed for node localization using the noisy RSSI distance estimates. ALLE, a modified version of LLE, considers the neighborhood around a node to determine the neighbors to approximate the node optimally. Experimental and simulation results show that ALLE is able to localize the nodes accurately in both clustered and centralized wireless sensor network. The centralized mechanism is found to have higher accuracy as compared with ALLE running on different cluster heads. However, this increase in accuracy is at the cost of significant energy overhead required for information gathering at the base station. Results also indicate that the ALLE is able to localize sensor nodes with an increased accuracy of around 9.38% as compared with native LLE.
Auteurs: Neeraj Jain;Shekhar Verma;Manish Kumar;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2949 - 2956
Editeur: IEEE
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» Adaptive Loop Shaping for Wideband Disturbances Attenuation in Precision Information Storage Systems
Résumé:
Modern hard disk drive (HDD) systems are subjected to various external disturbances. One particular category, defined as wide-band disturbances, can generate vibrations with their energy highly concentrated at several frequency bands. Such vibrations are commonly time-varying and strongly environment/product-dependent, and the wide spectral peaks can occur at frequencies above the servo bandwidth. This paper considers the attenuation of such challenging vibrations in the track-following problem of HDDs. Due to the fundamental limitation imposed by the Bode’s integral theorem, the attenuation of such wide-band disturbances may cause unacceptable amplifications at other frequencies. To achieve a good performance and an optimal tradeoff, an add-on adaptive vibration-compensation scheme is proposed in this paper. Through parameter adaptation algorithms that online identify both the center frequencies and the widths of the spectral peaks, the proposed control scheme automatically allocates the control efforts with respect to the real-time disturbance characteristics. The effect is that the position error signal in HDDs can be minimized with effective vibration cancelation. Evaluation of the proposed algorithm is performed by experiments on a voice-coil-driven flexible positioner system.
Auteurs: Liting Sun;Tianyu Jiang;Xu Chen;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 13
Editeur: IEEE
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» Adaptive LSTAR Model for Long-Range Variable Bit Rate Video Traffic Prediction
Résumé:
Static bandwidth allocation for variable bit rate (VBR) video traffic forfeits the available bandwidth. Prediction of the next frame size is thus useful in dynamic bandwidth allocation. It has been shown that VBR video traces are long-range dependent, which makes one-frame-ahead prediction insufficient for dynamic bandwidth allocation. Several studies have been conducted based on the linear autoregressive (AR) model to address VBR traffic prediction. In this paper, we propose the use of a nonlinear model from the AR family called logistic smooth transition autoregressive (LSTAR) to predict VBR video traffic. Furthermore, we introduce adaptive algorithms, including least mean square (LMS), normalized LMS (NLMS), kernel LMS (KLMS), and normalized KLMS (NKLMS), to obtain the parameters of the LSTAR model used in long-range VBR traffic prediction. In the proposed model, we do not separate traffic of different frame types and use only one predictor, which results in lower computational complexity. The performance of the proposed predictor for different prediction steps was evaluated and compared with recently introduced predictors. The results indicate that the proposed nonlinear LSTAR-based predictor yields better results than the optimum linear AR predictor, i.e., Wiener–Hopf and others.
Auteurs: Hashem Kalbkhani;Mahrokh G. Shayesteh;Nasser Haghighat;
Apparue dans: IEEE Transactions on Multimedia
Date publication: 05.-2017, volume: 19, issue:5, pages: 999 - 1014
Editeur: IEEE
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» Adaptive RFID Impedance Matching Based on Phase Difference for Oil Well Applications
Résumé:
Severe impedance mismatch problems due to the various environmental issues in downhole can greatly degrade the reliability of the radio-frequency identification (RFID) control system. In this brief, a new adaptive RFID impedance-matching system for oil well applications is presented, in which the measured real-time phase difference is employed to track the impedance mismatch information, while a variable capacitor array combined with a frequency sweep is used to rematch the mismatched impedance. Experiments have been performed and the results show that the impedance can be rematched perfectly when affected by from the various environmental influences.
Auteurs: Jixuan Zhu;Bo Tao;Zhouping Yin;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 525 - 529
Editeur: IEEE
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» Adaptive System Optimization Using Random Directions Stochastic Approximation
Résumé:
We present new algorithms for simulation optimization using random directions stochastic approximation (RDSA). These include first-order (gradient) as well as second-order (Newton) schemes. We incorporate both continuous-valued as well as discrete-valued perturbations into both types of algorithms. The former are chosen to be independent and identically distributed (i.i.d.) symmetric uniformly distributed random variables (r.v.), while the latter are i.i.d. asymmetric Bernoulli r.v.s. Our Newton algorithm, with a novel Hessian estimation scheme, requires $N$-dimensional perturbations and three loss measurements per iteration, whereas the simultaneous perturbation Newton search algorithm of [1] requires $2N$ -dimensional perturbations and four loss measurements per iteration. We prove the asymptotic unbiasedness of both gradient and Hessian estimates and asymptotic (strong) convergence for both first-order and second-order schemes. We also provide asymptotic normality results, which in particular establish that the asymmetric Bernoulli variant of Newton RDSA method is better than 2SPSA of [1]. Numerical experiments are used to validate the theoretical results.
Auteurs: Prashanth L. A.;Shalabh Bhatnagar;Michael Fu;Steve Marcus;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2223 - 2238
Editeur: IEEE
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» Adaptive Tracking Control for a Class of Stochastic Uncertain Nonlinear Systems With Input Saturation
Résumé:
In this technical note, the problem of adaptive tracking control is investigated for a class of stochastic uncertain nonlinear systems in the presence of input saturation. To analyze the effect of input saturation, an auxiliary system is employed. With the help of backstepping technique, an adaptive stochastic tracking control approach is developed. Under the proposed adaptive tracking controller, the boundedness of all the signals in the closed-loop system is achieved almost surely. Moreover, distinct from most of the existing results, the ultimate tracking error can be bounded by an explicit function of design parameters and input saturation error (the error between the control input and saturated input) in the mean quartic sense. Finally, an example is given to show the effectiveness of the proposed scheme.
Auteurs: Yong-Feng Gao;Xi-Ming Sun;Changyun Wen;Wei Wang;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2498 - 2504
Editeur: IEEE
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» Adaptive Tuning of Photonic Devices in a Photonic NoC Through Dynamic Workload Allocation
Résumé:
Photonic network-on-chip (PNoC) is a promising candidate to replace traditional electrical NoC in manycore systems that require substantial bandwidths. The photonic links in the PNoC comprise laser sources, optical ring resonators, passive waveguides, and photodetectors. Reliable link operation requires laser sources and ring resonators to have matching optical frequencies. However, inherent thermal sensitivity of photonic devices and manufacturing process variations can lead to a frequency mismatch. To avoid this mismatch, micro-heaters are used for thermal trimming and tuning, which can dissipate a significant amount of power. This paper proposes a novel FreqAlign workload allocation policy, accompanying an adaptive frequency tuning (AFT) policy, that is capable of reducing thermal tuning power of PNoC. FreqAlign uses thread allocation and thread migration to control temperature for matching the optical frequencies of ring resonators in each photonic link. The AFT policy reduces the remaining optical frequency difference among ring resonators and corresponding on-chip laser sources by hardware tuning methods. We use a full modeling stack of a PNoC that includes a performance simulator, a power simulator, and a thermal simulator with a temperature-dependent laser source power model to design and evaluate our proposed policies. Our experimental results demonstrate that FreqAlign reduces the resonant frequency gradient between ring resonators by 50%–60% when compared to existing workload allocation policies. Coupled with AFT, FreqAlign reduces localized thermal tuning power by 19.28 W on average, and is capable of saving up to 34.57 W when running realistic loads in a 256-core system without any performance degradation.
Auteurs: José L. Abellán;Ayse K. Coskun;Anjun Gu;Warren Jin;Ajay Joshi;Andrew B. Kahng;Jonathan Klamkin;Cristian Morales;John Recchio;Vaishnav Srinivas;Tiansheng Zhang;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 05.-2017, volume: 36, issue:5, pages: 801 - 814
Editeur: IEEE
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» Advanced Control of Thermostatic Loads for Rapid Frequency Response in Great Britain
Résumé:
In the Great Britain power system, reduced system inertia (particularly during low demand conditions) and larger possible infeed loss would make grid frequency regulation extremely challenging in future. Traditional primary frequency response could be insufficient to limit the frequency variation within acceptable range. This paper shows that thermostatically controlled loads (TCLs) (domestic refrigerators) can be controlled without real-time communication and in a nondisruptive way to collectively enhance the network frequency response. The aggregated power consumption of TCLs, distributed across the system, could be controlled as a ‘linear’ function of the locally measured frequency and its rate of change. Alternatively, their aggregated consumption could be made to follow a ‘pre-set’ power profile depending on the estimated infeed loss. A novel technique for accurate estimation of infeed loss and consequent postfault TCL power reduction is also proposed. The effectiveness of the two TCL control strategies is compared for primary and secondary frequency response through a case study on a 36 busbar reduced equivalent of the Great Britain power system. The effect of spatial variation of transient frequencies and the time delays in frequency measurement and filtering are considered to show how the TCLs can realistically provide rapid frequency response.
Auteurs: Vincenzo Trovato;Inmaculada Martínez Sanz;Balarko Chaudhuri;Goran Strbac;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2106 - 2117
Editeur: IEEE
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» Advanced electro-thermal life and reliability model for high voltage cable systems including accessories
Résumé:
A high voltage (HV) cable system consists of cable lengths and accessories. The latter are essentially - joints between adjacent cable lengths and - terminations at cable system ends, where the transition from insulated cables to bare overhead conductors, or to gas insulated substation components, takes place.
Auteurs: Giovanni Mazzanti;Massimo Marzinotto;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 05.-2017, volume: 33, issue:3, pages: 17 - 25
Editeur: IEEE
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» Advanced Fault-Monitoring Scheme for Ring-Based Long-Reach Optical Access Networks
Résumé:
This paper presents a novel fiber fault-monitoring system for long-reach optical access networks based on a transmission–reflection analysis approach. By launching an unmodulated continuous-wave optical signal into the feeder ring and measuring the transmitted and reflected/backscattered optical powers, the proposed monitoring scheme is able to detect, identify, and localize any major fault (covering both reflective and nonreflective events) with a good spatial accuracy (≤10 m) and a high detection speed (3 s). Both experimental and simulation results have demonstrated that the proposed system provides fiber monitoring functionality better than that obtained by the conventional methods.
Auteurs: Min Cen;Jiajia Chen;Véronique Moeyaert;Patrice Mégret;Marc Wuilpart;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1876 - 1886
Editeur: IEEE
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» Advanced Volume-Compensation Method for Indirect Finger Arterial Pressure Determination: Comparison with Brachial Sphygmomanometry
Résumé:
Objective: The so-called volume-compensation method (VCM) allows noninvasive instantaneous arterial blood pressure (BP) measurement in human fingers. The VCM is mostly carried out with photoplethysmography (PPG) to detect arterial volume pulsations. However, measurement errors may occur due to movement of the PPG sensors relative to skin and underlying vasculature. We report here the effectiveness of a new technique, “advanced VCM” (AVCM), developed by us to resolve this significant problem. Methods: The AVCM described uses a control system with procedures for adjusting system parameters derived from the pulsatile PPG signal and the finger cuff pressure. In open loop pre-operation, mean BP is estimated from a finger using the volume-oscillometric method. The control system reference is then adjusted to yield approximately equal values in mean BP and this gives optimum performance for instantaneous BP measurement. Systolic and diastolic BP values (SBP, DBP) from the instantaneous BP by the VCM and the AVCM were compared with the conventional brachial SBP/DBP measured simultaneously during 5-min baseline. SBP/DBP from the AVCM were also compared with brachial SBP/DBP during 36-min bicycle ergometer exercise. Results: Measurement errors that occurred when the BP measurement was run using the previous VCM essentially disappeared in the AVCM. Bland–Altman analysis revealed negligible fixed and proportional bias between finger SBP/DBP and brachial SBP/DBP. Conclusion: These findings suggest that the AVCM could be an effective technique to resolve the problem of measurement errors occurring with standard VCM. Significance: The newly proposed AVCM is potentially useful for all research and clinical situations where noninvasive continuous BP measurement is needed.
Auteurs: Kenta Matsumura;Takehiro Yamakoshi;Peter Rolfe;Ken-ichi Yamakoshi;
Apparue dans: IEEE Transactions on Biomedical Engineering
Date publication: 05.-2017, volume: 64, issue:5, pages: 1131 - 1137
Editeur: IEEE
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» Advances in Learning Technologies
Résumé:
New and innovative technologies enable a variety of instructional environments that help students overcome many traditional boundaries and constraints to learning. As the classroom becomes more of an abstraction than a physical space, educators and learners embrace a variety of pioneering tech-powered teaching and learning paradigms that will serve students well upon graduation.
Auteurs: Carl K. Chang;Sorel Reisman;Edmundo Tovar;
Apparue dans: Computer
Date publication: 05.-2017, volume: 50, issue:5, pages: 14 - 17
Editeur: IEEE
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» AI medicine comes to Africa's rural clinics
Résumé:
In rural health clinics across Kenya, women have started showing up with a surprising request: They've come for their "cervical selfies." ¶ Their enthusiasm is a good omen for a public health campaign against cervical cancer now under way in six African countries. Using an optical accessory that snaps onto any Android smartphone and makes use of its camera, health workers are examining women and catching early signs of cancer, enabling them to get immediate treatment. And soon this diagnostic device will be better still. With the integration of artificial intelligence, this technology may serve as a model for smarter health care in Africa and beyond.
Auteurs: Cary Champlin;David Bell;Celina Schocken;
Apparue dans: IEEE Spectrum
Date publication: 05.-2017, volume: 54, issue:5, pages: 42 - 48
Editeur: IEEE
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» Alcohol-Based Digital Etch for III–V Vertical Nanowires With Sub-10 nm Diameter
Résumé:
This letter introduces a novel alcohol-based digital etch technique for III–V FinFET and nanowire MOSFET fabrication. The new technique addresses the limitations of the conventional water-based approach in enabling structures with sub-10-nm 3-D features. Using the same oxidation step, the new technique shows an etch rate of 1 nm/cycle, identical to the conventional approach. Sub-10 nm fins and nanowires with a high mechanical yield have been achieved. InGaAs nanowires with a diameter of 5 nm and an aspect ratio greater than 40 have been demonstrated. The new technique has also been successfully applied to InGaSb-based heterostructures, the first demonstration of digital etch in this material system. Vertical InGaAs nanowire gate-all-around MOSFETs with a subthreshold swing of 70 mV/decade at ${V} _{mathrm { {DS}}}=$ 50 mV have been obtained at a nanowire diameter of 40 nm, demonstrating the good interfacial quality that the new technique provides.
Auteurs: Wenjie Lu;Xin Zhao;Dongsung Choi;Salim El Kazzi;Jesús A. del Alamo;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 548 - 551
Editeur: IEEE
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» Algorithms for Balanced Graph Colorings with Applications in Parallel Computing
Résumé:
Graph coloring—in a generic sense—is used to identify subsets of independent tasks in parallel scientific computing applications. Traditional coloring heuristics aim to reduce the number of colors used as that number also corresponds to the number of parallel steps in the application. However, if the color classes produced have a skew in their sizes, utilization of hardware resources becomes inefficient, especially for the smaller color classes. Equitable coloring is a theoretical formulation of coloring that guarantees a perfect balance among color classes, and its practical relaxation is referred to here as balanced coloring. In this paper, we consider balanced coloring models in the context of parallel computing. The goal is to achieve a balanced coloring of an input graph without increasing the number of colors that an algorithm oblivious to balance would have used. We propose and study multiple heuristics that aim to achieve such a balanced coloring for two variants of coloring problem, distance-1 coloring (the standard coloring problem) and partial distance-2 coloring (defined on a bipartite graph). We present parallelization approaches for multi-core and manycore architectures and cross-evaluate their effectiveness with respect to the quality of balance achieved and performance. Furthermore, we study the impact of the proposed balanced coloring heuristics on a concrete application-viz. parallel community detection, which is an example of an irregular application. In addition, we propose several extensions to our basic balancing schemes and evaluate their balancing efficacy and performance characteristics. The thorough treatment of balanced coloring presented in this paper from algorithms to application is expected to serve as a valuable resource to parallel application developers who seek to improve parallel performance of their applications using coloring.
Auteurs: Hao Lu;Mahantesh Halappanavar;Daniel Chavarría-Miranda;Assefaw H. Gebremedhin;Ajay Panyala;Ananth Kalyanaraman;
Apparue dans: IEEE Transactions on Parallel and Distributed Systems
Date publication: 05.-2017, volume: 28, issue:5, pages: 1240 - 1256
Editeur: IEEE
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» All Operation Region Characterization and Modeling of Drain and Gate Current Mismatch in 14-nm Fully Depleted SOI MOSFETs
Résumé:
In this paper, we present a complete study of the drain and gate current local variability in high- ${k}$ /metal gate-stack 14-nm fully depleted silicon-on-insulator CMOS transistors. A thorough experimental characterization of both drain and gate current mismatch was performed. In addition, we developed, for the first time, models of the drain and gate current mismatch, valid in all operation regions. Finally, we demonstrate the universal validity of our models through Monte Carlo simulations.
Auteurs: Theano A. Karatsori;Christoforos G. Theodorou;Emmanuel Josse;Charalabos A. Dimitriadis;G. Ghibaudo;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2080 - 2085
Editeur: IEEE
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» All Polymer FETs Direct-Written on Flexible Substrates Achieving MHz Operation Regime
Résumé:
We report the successful combination of digital, direct-writing techniques, such as inkjet printing and femtosecond laser writing in order to fabricate megahertz operating, all-polymer FETs on flexible substrates without the use of any mask. By a control of the layout of the device, maximizing the ratio between the channel area with respect to the total gate overlap area through a simple interdigitated scheme, the frequency of transition ${f}_{T}$ for an n-type polymer FET can be enhanced up to 4.9 MHz.
Auteurs: Sadir Gabriele Bucella;Andrea Perinot;Mario Caironi;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 1960 - 1967
Editeur: IEEE
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» All Regimes Parasitic Capacitances Extraction Using a Multi-Channel CBCM Technique
Résumé:
In this paper, we propose a multi-channel charge-based capacitance measurement (MCCBCM) technique for parasitic capacitances extraction of MOSFETs. The proposed technique is developed from a leakage- and parasitic-insensitive charge-based capacitance measurement technique, which is applied to measure gate-to-channel capacitance in certain regimes. Using the MCCBCM technique, we can measure all of the parasitic capacitance components of an MOSFET which are related to its terminals, such as the gate-to drain capacitance ( $ {C_{GD}}$ ), gate-to-source capacitance ( $ {C_{GS}}$ ), gate-to-bulk capacitance ( $ {C_{GB}}$ ), and so on. We designed a complex control methodology for the MCCBCM circuit. Specific control methods are provided for different parasitic capacitance components when MOSFETs work in different regimes. We can measure capacitances of sub-femto-farad level in all regimes, including the accumulation, depletion, and inversion regimes.
Auteurs: Peiyong Zhang;Qing Wan;Chenhui Feng;Huiyan Wang;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 05.-2017, volume: 30, issue:2, pages: 121 - 125
Editeur: IEEE
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» Allocation of Centralized Energy Storage System and Its Effect on Daily Grid Energy Generation Cost
Résumé:
The increasing limitations on available energy require use of new environmentally friendly resources and enhancement of utilization efficiency of available resources. Energy storage systems (ESSs) are a promising technology to realize such a goal; however, their application in networks requires an investment that must be economically justified. This study examined the effect of ESS use on energy generation costs in networks for a specific time period. This includes determining the best location for installation of the ESS and the best possible operation schedules for the ESS and power plants to achieve the greatest decrease in daily energy generation costs. The influences of all the factors affecting the final solution were studied under different scenarios. The effects of power plant cost functions, transmission line capacity, and network upgrades were compared. All scenarios were implemented in an IEEE standard 30-bus network. The best possible specifications of ESS can reduce daily energy generation cost by 3% for selected power plant cost functions. It was found that the use of ESS in a network uniformed stress on the transmission line and, in such a case, it would be possible to defer the network upgrade for 21 years.
Auteurs: Farshad Mohammadi;Hassan Gholami;Gevork B. Gharehpetian;Seyed Hossein Hosseinian;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2406 - 2416
Editeur: IEEE
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» Almost Universal Codes Achieving Ergodic MIMO Capacity Within a Constant Gap
Résumé:
This paper addresses the question of achieving capacity with lattice codes in multi-antenna block fading channels when the number of fading blocks tends to infinity. A design criterion based on the normalized minimum determinant is proposed for division algebra multi-block space-time codes over fading channels; this plays a similar role to the Hermite invariant for Gaussian channels. Under maximum likelihood decoding, it is shown that this criterion is sufficient to guarantee transmission rates within a constant gap from capacity both for deterministic channels and ergodic fading channels. Moreover, if the number of receive antennas is greater than or equal to the number of transmit antennas, the same constant gap is achieved under naive lattice decoding as well. In the case of independent identically distributed Rayleigh fading, the error probability vanishes exponentially fast. In contrast to the standard approach in the literature, which employs random lattice ensembles, the existence results in this paper are derived from the number theory. First, the gap to capacity is shown to depend on the discriminant of the chosen division algebra; then, class field theory is applied to build families of algebras with small discriminants. The key element in the construction is the choice of a sequence of division algebras whose centers are number fields with small root discriminants.
Auteurs: Laura Luzzi;Roope Vehkalahti;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3224 - 3241
Editeur: IEEE
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» Aloha from the IMS2017 Technical Program Committee Chairs
Résumé:
Provides a notice of upcoming conference events of interest to practitioners and researchers.
Auteurs: Olga Boric-Lubecke;Ryan Y. Miyamoto;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 24 - 26
Editeur: IEEE
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» Aloha from the State of Hawai'i
Résumé:
Presents information on the IMS 2017 Conference.
Auteurs: Justin Akagi;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 20 - 22
Editeur: IEEE
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» Amping Up the PA for 5G: Efficient GaN Power Amplifiers with Dynamic Supplies
Résumé:
Signals designed for high-capacity communications result in high peak-to-average ratio (PAR) waveforms that the transmitter power amplifier (PA) must amplify with low distortion. With emerging fifth-generation (5G) wireless systems, carrier frequencies and signal bandwidths are expected to increase significantly from the current S- and C-band allocations. All these factors are contributing to the increasingly challenging goals of maintaining transmitter PA efficiency for the following reasons.
Auteurs: Zoya Popovic;
Apparue dans: IEEE Microwave Magazine
Date publication: 05.-2017, volume: 18, issue:3, pages: 137 - 149
Editeur: IEEE
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» Amplifying the Signal of Metal Oxide Gas Sensors for Low Concentration Gas Detection
Résumé:
Nowadays, detection of trace concentration gases is still challenging for portable sensors, especially for the low-cost and easily operated metal–oxide–semiconductor (MOX) gas sensors. In this paper, a widely applicable amplification circuit is designed and fabricated to evidently enhance the signal of the MOX sensors by adding a field effect transistor (FET) into the conventional circuits. By optimizing the FET parameters and the loading resistance, this amplification circuit enables the commercial Figaro TGS2602 toluene sensors response effectively to the highest permissive limit (0.26 ppm) of toluene in indoor air of cars, with the detection limit of ~0.1 ppm. Furthermore, this circuit can also make the commercial Hanwei MP502 acetone sensors and MQ3 ethanol sensors response to the 1–2-ppm acetone in breath of diabetes and 2-ppm ethanol for fast and effectively drinker driver screening. The mechanism is investigated to be the gate voltage induced resistance change of the FET, with the highest theoretically estimated and experimentally measured magnification factor of 5–6. This FET amplifier can effectively enable the ppm level commercial MOX sensors response to sub-ppm level gases, promising for MOX gas sensor integration and also for other kind of resistive sensors.
Auteurs: Xinyuan Zhou;Ying Wang;Jinxiao Wang;Zheng Xie;Xiaofeng Wu;Ning Han;Yunfa Chen;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2841 - 2847
Editeur: IEEE
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» An $X$ -Band Half-Watt CMOS Power Amplifier Using Interweaved Parallel Combining Transformer
Résumé:
An $X$ -band half-watt fully integrated power amplifier (PA) using standard 0.18- $mu text{m}$ 1P6M CMOS technology is presented in this letter. Utilizing an interweaved three-primary parallel combining transformer, the CMOS PA delivers 27.1 dBm of measured saturation output power ( $P_{mathbf {sat}}$ ) with 22.7% of power-added efficiency at 9 GHz from a 3.3-V power supply. The measured output 1-dB gain compression point (OP1 dB) is 24.2 dBm and the gain performance is 11.2 dB at 9 GHz. The chip size is $1.045 times 0.84$ mm $^{{mathbf {2}}}$ . To the best of our knowledge, the PA is the first half-watt CMOS PA with excellent power density at the $X$ -band.
Auteurs: Jeng-Han Tsai;Jen-Wei Wang;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 05.-2017, volume: 27, issue:5, pages: 491 - 493
Editeur: IEEE
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» An 802.11a/b/g/n Digital Fractional- $N$ PLL With Automatic TDC Linearity Calibration for Spur Cancellation
Résumé:
A fractional-N digital phase-locked loop (PLL) architecture with low fractional spur is presented in this paper. A 2-D Vernier time-to-digital convertor (TDC) is implemented to achieve wide detection range with fine resolution. The TDC is calibrated automatically utilizing the ramp signal generated from the fractional-N accumulator for optimal linearity. A digi-phase spur cancellation technique with automatic TDC gain tracking is also implemented to further suppress the fractional spurs. The chip also includes an improved multimodulus divider (MMD) structure that overcomes the glitch problem during division ratio toggling associated with the prior art MMDs, enabling carrier synthesis across wide frequency range continuously. As part of an 802.11a/b/g/n transceiver, the DPLL can provide coverage for both 2.4/5 G WiFi bands. The proposed fractional-N DPLL is implemented in a 55-nm CMOS technology. The DPLL achieves a largest fractional spur level of −55 dBc without using a sigma–delta modulator and an in-band phase noise of −107 dBc/Hz (0.55 ps integrated jitter) while consuming 9.9 mW.
Auteurs: Dongyi Liao;Hechen Wang;Fa Foster Dai;Yang Xu;Roc Berenguer;Sara Munoz Hermoso;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 05.-2017, volume: 52, issue:5, pages: 1210 - 1220
Editeur: IEEE
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» An AC Input Switching-Converter-Free LED Driver With Low-Frequency-Flicker Reduction
Résumé:
This paper presents a novel switching-converter-free ac–dc light-emitting diode (LED) driver with low-frequency-flicker reduction for general lighting applications. The proposed driving solution can minimize the system size as it enables the monolithic integration of the controller and power transistors while both the bulky off-chip electrolytic capacitors and magnetics are eliminated. Moreover, the driver can effectively reduce the harmful optical flicker at the double-line-frequency by employing a novel quasi-constant power control scheme while maintaining high efficiency and a good power factor (PF). The proposed driver is implemented with a single controller integrated circuit chip, which includes the controller and high-voltage power transistors, and the off-chip diode bridge and valley-fill circuit. The chip is fabricated with a 0.35- $mu text{m}$ 120-V high-voltage CMOS process and occupies 1.85 mm2. The driver can provide up to 7.8-W power to the LED and achieves 87.6% peak efficiency and an over 0.925 PF with only 17.3% flicker from a 110-Vac 60-Hz input.
Auteurs: Yuan Gao;Lisong Li;Philip K. T. Mok;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 05.-2017, volume: 52, issue:5, pages: 1424 - 1434
Editeur: IEEE
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» An Active Microwave Sensor for Near Field Imaging
Résumé:
Near-field imaging using microwaves in medical applications is of great current interest for its capability and accuracy in identifying features of interest, in comparison with other known screening tools. This paper documents microwave imaging experiments on breast cancer detection, using active antenna tuning to obtain matching over a wide bandwidth. A simple phantom consisting of a plastic container with a low dielectric material emulating fatty tissue and a high dielectric constant object emulating a tumor is scanned between 4 and 8 GHz with a ultra-wideband microstrip antenna. Measurements indicate that this prototype microwave sensor is a good candidate for such imaging applications.
Auteurs: Ahmed Faraz Mirza;Chan Hwang See;Isah Musa Danjuma;Rameez Asif;Raed A. Abd-Alhameed;James M. Noras;Roger W. Clarke;Peter S. Excell;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2749 - 2757
Editeur: IEEE
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» An Adaptive Background Modeling Method for Foreground Segmentation
Résumé:
Background modeling has played an important role in detecting the foreground for video analysis. In this paper, we presented a novel background modeling method for foreground segmentation. The innovations of the proposed method lie in the joint usage of the pixel-based adaptive segmentation method and the background updating strategy, which is performed in both pixel and object levels. Current pixel-based adaptive segmentation method only updates the background at the pixel level and does not take into account the physical changes of the object, which may result in a series of problems in foreground detection, e.g., a static or low-speed object is updated too fast or merely a partial foreground region is properly detected. To avoid these deficiencies, we used a counter to place the foreground pixels into two categories (illumination and object). The proposed method extracted a correct foreground object by controlling the updating time of the pixels belonging to an object or an illumination region respectively. Extensive experiments showed that our method is more competitive than the state-of-the-art foreground detection methods, particularly in the intermittent object motion scenario. Moreover, we also analyzed the efficiency of our method in different situations to show that the proposed method is available for real-time applications.
Auteurs: Zuofeng Zhong;Bob Zhang;Guangming Lu;Yong Zhao;Yong Xu;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1109 - 1121
Editeur: IEEE
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» An Adaptive Fusion Strategy for Distributed Information Estimation Over Cooperative Multi-Agent Networks
Résumé:
In this paper, we study the problem of distributed information estimation that is closely relevant to some network-based applications, such as distributed surveillance, cooperative localization, and optimization. We consider a problem where an application area containing multiple information sources of interest is divided into a series of subregions in which only one information source exists. The information is presented as a signal variable, which has finite states associated with certain probabilities. The probability distribution of information states of all the subregions constitutes a global information picture for the whole area. Agents with limited measurement and communication ranges are assumed to monitor the area, and cooperatively create a local estimate of the global information. To efficiently approximate the actual global information using individual agents’ own estimates, we propose an adaptive distributed information fusion strategy and use it to enhance the local Bayesian rule-based updating procedure. Specifically, this adaptive fusion strategy is induced by iteratively minimizing a Jensen–Shannon divergence-based objective function. A constrained optimization model is also presented to derive minimum Jensen–Shannon divergence weights at each agent for fusing local neighbors’ individual estimates. Theoretical analysis and numerical results are supplemented to show the convergence performance and effectiveness of the proposed solution.
Auteurs: Daxin Tian;Jianshan Zhou;Zhengguo Sheng;
Apparue dans: IEEE Transactions on Information Theory
Date publication: 05.-2017, volume: 63, issue:5, pages: 3076 - 3091
Editeur: IEEE
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» An All-Passive Negative Feedback Network for Broadband and Wide Field-of-View Self-Steering Beam-Forming With Zero DC Power Consumption
Résumé:
This paper presents an all-passive negative feedback network that performs autonomous radio-frequency (RF) front-end beam-forming and dynamic beam-tracking toward the direction of the incident RF signal. The proposed feedback network consists of a passive RF signal processing network, voltage rectifiers, and voltage-controlled delay-line phased shifters, all of which are passive-only circuits. The negative feedback loop is realized by passive phase detection, phase-to-voltage conversion, and voltage-controlled phase shifting, achieving a large loop-gain and autonomous operation with zero DC power consumption. The nonlinear behavior of the loop is exploited to substantially expand the array field of view (FoV). A proof-of-concept broadband four-element all-passive self-steering beam-former at 5 GHz with a wide FoV is implemented in a standard 130 nm CMOS process. A high-quality four-element synthesized array factor is measured for the input progressive phase shift $phi _{mathrm {in}}$ from −180° to 180°. When the proposed negative feedback loop is enabled, the normalized array factor is −2.87/−2.8 dB at $phi _{mathrm {in}}= + 90^{circ }$ /−90° with an input RF power $text{P}_{mathrm {in}}$ of −17 dBm/element at 5 GHz, achieving >25 dB array factor improvement over the open-loop operation. Moreover, the nonlinear feedback loop allows for significant array factor improvement even at $phi _{mathrm {in}} = +180^{circ }$ /−180°. The proposed beam-former also achieves high- quality self-steering beam-forming from 4 to 5.68 GHz with 34.7% fractional bandwidth. Therefore, the proof-of-concept all-passive self-steering beam-former outperforms the state-of-the-art active designs in terms of beam-forming quality, FoV, and fractional bandwidth. To the best of the authors’ knowledge, this is the first demonstration of an all-passive negative feedback network for a broadband and wide FoV self-steering beam-forming with zero DC power consumption.
Auteurs: Min-Yu Huang;Taiyun Chi;Fei Wang;Hua Wang;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 05.-2017, volume: 52, issue:5, pages: 1260 - 1273
Editeur: IEEE
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» An Alternative Direction Decomposition Scheme and Error Analysis for Parabolic Equation Model
Résumé:
Alternate direction implicit (ADI) method has been widely used to analyze the tunnel propagation or electromagnetic scattering problem for the finite difference method. In this paper, a novel alternate direction decomposition (ADD) scheme is proposed to simplify the split-step Fourier transform (SSFT) algorithm in parabolic equation (PE) model. The spatial matrix of electric field is decoupled into two subarrays by ADD-SSFT algorithm, which is used to decrease the computational burden for 3-D PE problems in a large scale environment after the integration order exchanged. Also, the phase error of this approximation is analyzed to show the algorithm performance, along with several numerical results, including the tunnel cases with traditional modal theory, and they are provided to validate and calibrate the PE model, and demonstrate the efficiency and accuracy of the proposed algorithm. Moreover, the scattering computation is investigated and compared with multilevel fast multipole method to show that ADD-SSFT is appropriate for solving the scattering problems for the electrical large target.
Auteurs: Liang Zhou;Cheng Liao;Xiangzheng Xiong;Qinghong Zhang;Dongming Zhang;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2547 - 2557
Editeur: IEEE
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» An Analytical Model for the Threshold Voltage of Intrinsic Channel MOSFET Having Bulk Trap Charges
Résumé:
An analytical model for the bulk trap charge-induced threshold voltage variation in the intrinsic channel MOSFET is presented. A new definition of the flat band voltage, the gate voltage necessary to nullify the gate charge, which is induced by the bulk charges, is introduced. With the newly defined flat band voltage based on the bulk charge sheet approximation, the analytical MOS equations are derived for both the intrinsic channel nanowire and planar MOSFETs. It is shown that the analytical models predict the device characteristics reasonably well, compared with the numerical device simulations. Also, the error induced by the charge sheet approximation is compared with the point charge, using the numerical simulation. The model will be useful to predict the threshold voltage variation of the intrinsic poly-Si, adopted by the modern 3-D nand flash memory cell transistors.
Auteurs: Hyunwoo Jo;Seongwook Choi;Sungman Rhee;Young June Park;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2113 - 2120
Editeur: IEEE
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» An Approach for Estimating Disturbance Arrival Time Based on Structural Frame Model
Résumé:
With the development of power grid interconnection, disturbance propagation phenomena are more and more apparent in the form of electromechanical waves. Once a disturbance occurs, its propagation might cause cascading events and even large blackouts. With the help of advanced communications networks in smart grids, new event-based protection systems can be devised by the reveal of disturbance propagation mechanisms. In this paper, a widely used measurement-based protection system is analyzed and the idea of event-based protection is proposed. By introducing the inverse process of lumped mass method, the impact scope of generator inertia is proposed. Then, the structural frame model of power networks for disturbance propagation is built, which is sectionalized homogeneously. The spatial heterogeneity of propagation velocity of the electromechanical waves is depicted. According to the constant velocity characteristic of the segments in the structural frame model, a weighted undirected graph is formulated. Then, the Dijkstra algorithm based shortest path searching method for arrival time of electromechanical wave is proposed. The simulations are carried out to demonstrate the effectiveness of the proposed electromechanical wave propagation model and disturbance arrival time estimation algorithm. The research work is one of the essential steps for realizing event-based protection strategies.
Auteurs: Tianshu Bi;Junda Qin;Yuehao Yan;Hao Liu;Kenneth E. Martin;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1741 - 1750
Editeur: IEEE
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» An Azimuth-Variant Autofocus Scheme of Bistatic Forward-Looking Synthetic Aperture Radar
Résumé:
In bistatic forward-looking synthetic aperture radar (BFSAR), conventional autofocus algorithms cannot estimate the phase errors accurately when the range walk is compensated in the azimuthal time domain. This problem stems from the influence of the azimuth-variant Doppler coefficients after linear range cell migration correction in azimuthal time domain. In principle, nonlinear chirp scaling processing can be carried out to remove the azimuth variance. Nevertheless, Doppler azimuth variations of the Doppler parameters induced by the motion errors are not taken into consideration and serious defocus would emerge in the final image. To cope with such a problem, an estimation–evaluation–equalization scheme is proposed before conventional autofocus for BFSAR. Different from the conventional autofocus method, the azimuth-variant Doppler coefficients are additionally estimated and equalized before autofocus, and as a consequence, phase errors can be precisely estimated. The BFSAR data processing results demonstrate the validity of the proposed method on the improvement of autofocus in BFSAR.
Auteurs: Wei Pu;Wenchao Li;Junjie Wu;Yulin Huang;Jianyu Yang;Haiguang Yang;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 689 - 693
Editeur: IEEE
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» An Effective Approach for Associating the Sources of Defect Signatures to Process Zones
Résumé:
A semiconductor wafer undergoes various processing steps before it is transformed from a plain silicon wafer to one populated with thousands of integrated circuits. Each of these processing steps is susceptible to specific types of defects. Some defects may not be captured by in-line inspection tools or may not be sampled during defect review-scanning electron microscope and are carried over multiple processing steps. Such defects can be discovered at the end of the fabrication procedure, which requires process engineers to trace back the manufacturing processes that caused these defects. Despite the success of most current methods that detect defects during wafer fabrication, most of these methods are inable to accurately associate the source of an individual defect type to a specific semiconductor processing step. We believe that this limitation can be overcome by considering the carry-over of defect signatures rather than individual defects. We propose in this paper a system called step-defect contribution analyzer (SDCA) that detects defect signatures on semiconductor wafers and overcomes the limitations outlined above. SDCA allows process engineers to trace back and associate the source of a final defectivity discovered at the end of the fabrication procedure to specific defect signatures carried over multiple process zones. We experimentally evaluated the quality of SDCA by measuring its prediction accuracy. Results revealed marked prediction accuracy.
Auteurs: Kamal Taha;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 05.-2017, volume: 30, issue:2, pages: 176 - 184
Editeur: IEEE
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» An Effective Method Based on ACF for Aircraft Detection in Remote Sensing Images
Résumé:
Detecting artificial targets, such as aircraft, in satellite images is significant in military and civil applications. Although the performance has improved with the use of more complicated features and better learning methods, effectively handling aircraft with variations of type, pose, and size is still very challenging. To solve this problem, we propose a multiscale sliding-window framework based on aggregate channel features, well-designed features that contain rich information. We also employ a fast feature pyramids algorithm to accelerate multiscale aircraft detection. In this framework, features are trained by Cascade AdaBoost including multiple rounds of bootstrapping that leads to improved overall accuracy. A two-step nonmaximum suppression algorithm is carefully designed based on a given set of detections. Our method shows a competitive performance on the QuickBird images of 0.6 m resolution.
Auteurs: An Zhao;Kun Fu;Hao Sun;Xian Sun;Feng Li;Daobing Zhang;Hongqi Wang;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 744 - 748
Editeur: IEEE
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» An Effective Method for Synthesizing Multiple-Pattern Linear Arrays With a Reduced Number of Antenna Elements
Résumé:
An innovative technique based on the enhanced unitary matrix pencil (MP) method is presented for the design of sparse multiple-pattern linear arrays. By virtue of the equivalent MP obtained with a unitary transformation, the relation between the element positions and the generalized eigenvalues is achieved in this method, which contributes to the real solutions of the common element positions for all multiple patterns. Owing to the utilization of a unitary transformation that can convert a complex matrix to a real one, the computational complexity can be significantly reduced since only the real computations are involved in the singular value decomposition and eigenvalue decomposition procedures. Consequently, by only varying the obtained excitation distributions, different patterns are generated with a higher matching accuracy. Representative experiments are provided to validate the effectiveness and advantages of the proposed method.
Auteurs: Haiou Shen;Buhong Wang;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2358 - 2366
Editeur: IEEE
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» An Efficient and Accurate Solution for Distribution System State Estimation with Multiarea Architecture
Résumé:
Distribution system state estimation (DSSE) is an essential tool for the management and control of future distribution networks. Distribution grids are usually characterized by a very large number of nodes and different voltage levels. Moreover, different portions of the system can be operated by different distribution system operators. In this context, multiarea approaches are key tools to efficiently perform DSSE. This paper presents a novel approach for multiarea state estimation in distribution systems. The proposed algorithm is based on a two-step procedure, where the first-step local estimations are refined through a newly designed second step that allows the integration of the measurement information available in the adjacent areas. The main novelty in this paper is the mathematical analysis of the impact brought by possible measurements shared among different areas, which drives the design of a new efficient weighted least squares formulation of the second step to maximize the achievable estimation accuracy. Tests performed on the unbalanced IEEE 123-bus network prove the goodness of the new multiarea estimator proposed and show the accuracy and efficiency enhancements obtainable with respect to previous literature.
Auteurs: Marco Pau;Ferdinanda Ponci;Antonello Monti;Sara Sulis;Carlo Muscas;Paolo Attilio Pegoraro;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 910 - 919
Editeur: IEEE
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» An Efficient Eligible Error Locator Polynomial Searching Algorithm and Hardware Architecture for One-Pass Chase Decoding of BCH Codes
Résumé:
In numerous memory and communication systems, Bose–Chaudhuri–Hocquenghem (BCH) codes are widely employed to enhance reliability. A one-pass Chase soft-decision decoding algorithm for BCH codes was previously proposed to achieve significant performance improvement over traditional hard-decision decoding while not increasing too much computational complexity. The bottleneck in conventional one-pass Chase decoding is the procedure of judging whether an obtained error locator polynomial is valid. In this brief, a novel algorithm that can efficiently verify eligibility of each generated error locator polynomial is proposed. The problem is first reformulated as a polynomial modulo problem, where repeated squaring can be employed for further simplification. In order to decrease the critical path delay and hardware complexity, an efficient polynomial division algorithm based on polynomial inversion is also proposed. In addition, a VLSI architecture for the proposed algorithm is presented. The implemented results show that the proposed eligibility checking algorithm reduces the gate counts to only 12% of a conventional polynomial selection algorithm without introducing any speed penalty. The projected area reduction achieved in a complete one-pass Chase decoder is approximately 75%. In addition, post-layout simulation shows that the proposed algorithm is 20 times more power efficient than the conventional method.
Auteurs: Nan Zheng;Pinaki Mazumder;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 580 - 584
Editeur: IEEE
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» An Efficient Game for Coordinating Electric Vehicle Charging
Résumé:
A novel class of auction-based games is formulated to study coordination problems arising from charging a population of electric vehicles (EVs) over a finite horizon. To compete for energy allocation over the horizon, each individual EV submits a multidimensional bid, with the dimension equal to two times the number of time-steps in the horizon. Use of the progressive second price (PSP) auction mechanism ensures that incentive compatibility holds for the auction games. However, due to the cross elasticity of EVs over the charging horizon, the marginal valuation of an individual EV at a particular time is determined by both the demand at that time and the total demand over the entire horizon. This difficulty is addressed by partitioning the allowable set of bid profiles based on the total desired energy over the entire horizon. It is shown that the efficient bid profile over the charging horizon is a Nash equilibrium of the underlying auction game. An update mechanism for the auction game is designed. A numerical example demonstrates that the auction process converges to an efficient Nash equilibrium. The auction-based charging coordination scheme is adapted to a receding horizon formulation to account for disturbances and forecast uncertainty.
Auteurs: Suli Zou;Zhongjing Ma;Xiangdong Liu;Ian Hiskens;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2374 - 2389
Editeur: IEEE
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» An Efficient Indexing Method for Skyline Computations with Partially Ordered Domains
Résumé:
Efficient processing of skyline queries with partially ordered domains has been intensively addressed in recent years. To further reduce the query processing time to support high-responsive applications, the skyline queries that were previously processed with user preferences similar to those of the new query contribute useful candidate result points. Hence, the answered queries can be cached with both their results and the user preferences such that the query processor can rapidly retrieve the result for a new query only from the result sets of cached queries with compatible user preferences. When caching a significant number of queries accumulated over time, it is essential to adopt effective access methods to index the cached queries to retrieve a set of relevant cached queries for facilitating the cache-based skyline query computations. In this paper, we propose an extended depth-first search indexing method (e-DFS for short) for accessing user preference profiles represented by directed acyclic graphs (DAGs), and emphasize the design of the e-DFS encoding that effectively encodes a user preference profile into a low-dimensional feature point which is eventually indexed by an R-tree. We obtain one or more traversal orders for each node in a DAG by traversing it through a modified version of the depth-first search which is utilized to examine the topology structure and dominance relations to measure closeness or similarity. As a result, e-DFS which combines the criteria of similarity evaluation is able to greatly reduce the search space by filtering out most of the irrelevant cached queries such that the query processor can avoid accessing the entire data set to compute the query results. Extensive experiments are presented to demonstrate the performance and utility of our indexing method, which outperforms the baseline planning techniques by reducing 37 percent of the computational time on average.
Auteurs: Yu-Ling Hsueh;Chia-Chun Lin;Chia-Che Chang;
Apparue dans: IEEE Transactions on Knowledge and Data Engineering
Date publication: 05.-2017, volume: 29, issue:5, pages: 963 - 976
Editeur: IEEE
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» An Efficient Narrowband Interference Suppression Approach in Ultra-Wideband Receiver
Résumé:
Ultra-wideband (UWB) radio will be sharing the propagation environment with other pre-existing wireless systems, some possibly creating UWB multiple access interference, and others creating narrowband interference in the UWB radio bands. The Federal Communications Commission regulations have set conditions that limit the interference from the UWB radiators to other wireless systems, however, the issue of eliminating interference to the UWB radios from the pre-narrow band interference existing system is left to the ingenuity of the UWB radio designer. To optimize the performance of UWB wireless communication systems deteriorated by strong narrowband interferences, a high-efficiency interference suppression scheme is proposed in this paper. The closed-form weight coefficient iteration expression of basic adaptive notch filter cell with two constrained zero-pole pairs is derived. For multiple narrowband interferences case, a high-order cascaded adaptive interference suppression scheme is also presented. The simulation result demonstrates that the proposed narrowband interference suppression approach has excellent suppression effects to narrowband interferences in UWB systems, since a significant signal to noise ratio improvement is obtained. In addition, the proposed narrowband interference suppression algorithm is particularly fit for low-cost UWB wireless reception connected with Rake combining techniques.
Auteurs: Hailiang Xiong;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:9, pages: 2741 - 2748
Editeur: IEEE
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» An Efficient Semianalytical Method for Hypersingularity Treatment Over Curved Patches
Résumé:
In this communication, we propose an efficient method to evaluate hypersingular integrals defined on curved surfaces. First an exact expression for hypersingular kernel is derived by projecting the integral on curvilinear element on a flat surface. Next singularity subtraction employed, where the singular core is hypersingular and the remaining part is weakly singular. The singular core is evaluated analytically using finite part interpretation and the remaining weakly singular part is evaluated numerically using Gauss–Legendre quadrature rules. By numerical experiments we have shown that the convergence rate of the purposed method is quite high even for few number of quadrature nodes. Accuracies over ten digits are obtained for relatively large and highly curved surfaces, which may cover entire domain of local corrections in Nyström method.
Auteurs: G. Selcuk;S. Koc;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2740 - 2744
Editeur: IEEE
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» An Electronically Scannable Reflector Antenna Using a Planar Active Array Feed at Ka-Band
Résumé:
This contribution presents the system design procedure and performance of an array fed reflector antenna. Combining the inherent benefits of a reflector antenna—high gain, low-cost, and simplicity—with the agility provided by a scannable active array feed, enables a new range of applications, for instance in commercial mobile antenna terminals. The whole arrangement features a restricted field of view for either scanning or multibeam applications. To minimize system cost, a planar patch antenna array in printed circuit board technology is used for the feed and the reflector diameter is restricted to 60 cm. To obtain optimal performance, both the reflector and the feed are specifically designed for the desired application, i.e., mobile satellite communication at Ka-band. A comprehensive study of various rotationally symmetric reflectors is carried out to determine arrangements maximizing the field of view and still complying with the respective regulations. For the feed, a 30 GHz transmit array with 49 elements is developed, enabling 2-D scanning in a ±6° conical sector. It includes a wideband signal distribution network and frontend electronics.
Auteurs: Benjamin Rohrdantz;Thomas Jaschke;Torsten Reuschel;Stefan Radzijewski;Anton Sieganschin;Arne F. Jacob;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1650 - 1661
Editeur: IEEE
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» An Energy-Efficient Frequency-Domain CMOS Temperature Sensor With Switched Vernier Time-to-Digital Conversion
Résumé:
This paper presents a CMOS smart temperature sensor using a switched Vernier time-to-digital converter to achieve an energy-efficient temperature sensing. The proposed temperature sensor employs two switched ring oscillators (SROs), of which the oscillation frequencies are slightly different from each other and varying linearly with temperature due to the deployment of a proportional-to-absolute-temperature current generator. The frequencies of the two SROs are measured by counting the rising edges with two counters, and hence, the frequency difference corresponding to temperature can be readily monitored with the digital numbers. A control strategy that switches OFF the ring oscillators after each sampling is developed, such that significant power saving is achieved. The proposed temperature sensor shows a measured resolution of 0.048 °C from −20 °C to 120 °C with 100-ms conversation time. With 1-kHz sampling rate, the power consumption is as small as 93.6 $mu text{W}$ , resulting in 93.6 nJ per sampling. The chip area is 0.118 mm2 in a standard 0.18- $mu text{m}$ CMOS process.
Auteurs: Qiwei Huang;Hyobin Joo;Jinwoo Kim;Chenchang Zhan;Jinwook Burm;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3001 - 3011
Editeur: IEEE
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» An Energy-Efficient Tensile-Strained Ge/InGaAs TFET 7T SRAM Cell Architecture for Ultralow-Voltage Applications
Résumé:
In this paper, we benchmark the read/write performance and standby power of several static random access memory (SRAM) cell architectures utilizing 45-nm Si CMOS MOSFET and/or tensile-strainedGe/InGaAs tunnel FET (TFET) devices under low-voltage operation ( $0.2~text {V} le vert {V}_{text {DD}}vert le 0.6$ V). We then introduce a novel tensile-strained Ge/InGaAs TFET-based SRAM circuit using several access schemes and investigate the impact of cell access design on static and dynamic performance. SRAM cells utilizing outwardaccess transistors exhibit wide read andwrite static noise margins, but suffer from increased read delay times. A 7T SRAM cell architecture is proposed in order to resolve the degraded read delay time. Cell standby energy was found to exhibit a strong dependenceon operational voltage andGe strain state. Variation of theGe strain state from 1.5% to 3% resulted in an up to 98% reduction in cell standby energy ( $vert {V}_{text {DD}}vert = 0.6$ V) as compared with similar CMOS-based SRAM cells. These results demonstrate the superior performance of the proposed 7T TFET SRAM design for operation in the low- and ultralow-voltage regime.
Auteurs: Jheng-Sin Liu;Michael B. Clavel;Mantu K. Hudait;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2193 - 2200
Editeur: IEEE
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» An Enhancement of Crosstalk Avoidance Code Based on Fibonacci Numeral System for Through Silicon Vias
Résumé:
Through silicon vias (TSVs) play an important role as the vertical electrical connections in 3-D stacked integrated circuits. However, the closely clustered TSVs suffer from the crosstalk noise between the neighboring TSVs, and result in the extra delay and the deterioration of signal integrity. For a $3 times 3$ TSV array, the severity of crosstalk noise in the center victim TSV is classified into 11 levels, which is defined as 0C to 10C from low noise to high noise, depending on the combinations of the digital patterns applied to the TSV array. An enhanced code based on the Fibonacci number system (FNS) to suppress the crosstalk noise below 6C level is proposed, in which both the redundancy of numbers and the nonuniqueness of Fibonacci-based binary codeword are utilized to search the proper codeword. Experimental results show that the proposed technique decreases about 22% latency of TSVs comparing with the worst crosstalk cases. This technique is applicable in the large-scale TSV array for it has a quasi-linear hardware overhead, and its system overhead is less than that of the 3-D 4-LAT counterpart if the data width is greater than 18, and it has good usability for it consumes less power per TSV and achieves lower bit error rate at the interested frequency range comparing with that of the original FNS coding technique.
Auteurs: Xiaole Cui;Xiaoxin Cui;Yewen Ni;Min Miao;Jin Yufeng;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1601 - 1610
Editeur: IEEE
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» An Exact Linearization Method for OLTC of Transformer in Branch Flow Model
Résumé:
The branch flow based optimal power flow (OPF) problem in radially operated distribution networks can be exactly relaxed to a second-order cone programming model without considering transformers. However, the introduction of nonlinear transformer models will make the OPF model nonconvex. This letter presents an exact linearized transformer's on-load tap-changer model to keep the OPF model convex via a binary expansion scheme and big-M method. Validity of the proposed method is verified using IEEE 33-bus test network.
Auteurs: Wenchuan Wu;Zhuang Tian;Boming Zhang;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2475 - 2476
Editeur: IEEE
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» An Improved DTC Technique for Low-Speed Operation of a Five-Phase Induction Motor
Résumé:
In this paper, an improved direct torque control (DTC) technique of a two-level inverter-fed five-phase induction motor (FPIM) drive for low-speed operation is presented. The operation of the FPIM with distributed winding requires the elimination of third-harmonic voltage, which, if not taken care of, would generate distorted stator current. For this, the concept of virtual vectors (VVs) is utilized. Before selecting the VVs for the DTC operation, a theoretical analysis is carried out to find the effects of these VVs on the torque and flux response of the FPIM under different speed and loading conditions. It is found that the rotor speed plays a crucial role in the selection of VVs. A particular VV has different effects on the torque change as speed varies. This analysis helps in the selection of VVs, hysteresis torque bandwidth, flux bandwidth, and efficient formation of sectors. Furthermore, in this paper, the performance of the FPIM during low-speed operation is improved by avoiding the demagnetization of the stator flux. To achieve this, a new modified lookup table is proposed. Superiority of the proposed method over the reported approaches is illustrated by experimental results.
Auteurs: Saifullah Payami;Ranjan Kumar Behera;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3513 - 3523
Editeur: IEEE
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» An Improved Move-Blocking Strategy in Predictive Control for Setpoint Tracking
Résumé:
One of the main features of model predictive control is its ability to incorporate in the computation of the control law the advance (future) knowledge of the setpoint trajectory. Nevertheless, it can be shown that the standard move-blocking approaches that take into account this future information could reduce rather than improve its performance with no stability guarantees. Therefore, objective of this paper is first demonstrate where existing algorithms have weaknesses and then develop an algorithm based on move-blocking which allows nominal stability guarantees, optimal nominal performance and tracking.
Auteurs: Guillermo Valencia Palomo;Francisco Ronay Lopez Estrada;Carlos Daniel Garcia Beltran;Jorge Alberto Orrante Sakanassi;Jose Antonio Hoyo Montano;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 806 - 812
Editeur: IEEE
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» An Indirect Data-Driven Method for Trajectory Tracking Control of a Class of Nonlinear Discrete-Time Systems
Résumé:
This paper presents an indirect data-driven method for the trajectory tracking control problem of a class of nonlinear discrete-time systems, which have unknown dynamics. This method first establishes an approximate model of the controlled object using historical I/O data and neural network; then, designs and adjusts the feedback gain matrix online using measured output data and previous estimates. This is an adaptive control process of prediction, estimation, and adjustment, which needs to solve some nonlinear optimization problems online, can overcome the adverse effects of the modeling errors caused by neural networks, and is the key to making the system output asymptotically track the reference trajectory. The convergence analysis and simulation results demonstrate the effectiveness and feasibility of the presented method. In addition, based on Lagrange's mean value theorem, we also give an online linearization technique which is applicable to nonlinear discrete-time systems, whose dynamic models have continuous partial derivatives with respect to the input and the output.
Auteurs: Zhuo Wang;Renquan Lu;Furong Gao;Derong Liu;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4121 - 4129
Editeur: IEEE
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» An Inductive 2-D Position Detection IC With 99.8% Accuracy for Automotive EMR Gear Control System
Résumé:
In this paper, the analog front end (AFE) for an inductive position sensor in an automotive electromagnetic resonance gear control applications is presented. To improve the position detection accuracy, a coil driver with an automatic two-step impedance calibration is proposed which, despite the load variation, provides the desired driving capability by controlling the main driver size. Also, a time shared analog-to-digital converter (ADC) is proposed to convert eight-phase signals while reducing the current consumption and area to 1/8 of the conventional structure. A relaxation oscillator with temperature compensation is proposed to generate a constant clock frequency in vehicle temperature conditions. This chip is fabricated using a 0.18- $mu text{m}$ CMOS process and the die area is 2 mm $times 1.5$ mm. The power consumption of the AFE is 23.1 mW from the supply voltage of 3.3 V to drive one transmitter (Tx) coil and eight receiver (Rx) coils. The measured position detection accuracy is greater than 99.8 %. The measurement of the Tx shows a driving capability higher than 35 mA with respect to the load change.
Auteurs: SangYun Kim;Hamed Abbasizadeh;Imran Ali;Hongjin Kim;SungHun Cho;YoungGun Pu;Sang-Sun Yoo;Minjae Lee;Keum Cheol Hwang;Youngoo Yang;Kang-Yoon Lee;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 05.-2017, volume: 25, issue:5, pages: 1731 - 1741
Editeur: IEEE
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» An Integrated Dynamic Modeling and Adaptive Controller Approach for Flywheel Augmented DFIG Based Wind System
Résumé:
This paper presents an integrated Doubly Fed Induction Generator (DFIG) and flywheel energy storage architecture that provide output power stability based on a new dynamic adaptive control approach. First, a grid-connected two-mass DFIG and a grid-supportive single-mass squirrel cage induction generator based flywheel energy storage system models have been considered for controller design and proof of concept exploration. Second, new adaptive dynamic control architecture is designed for active and reactive power balancing from wind farm with flywheel energy storage during normal and abnormal operating conditions. The proposed architecture is very effective in mitigating oscillations, thus providing a novel methodology for a stable microgrid or increasing wind energy penetration to the grid.
Auteurs: Sudipta Ghosh;Sukumar Kamalasadan;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2161 - 2171
Editeur: IEEE
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» An Integrated Model-Data-Based Zero-Phase Error Tracking Feedforward Control Strategy With Application to an Ultraprecision Wafer Stage
Résumé:
In precision motion control, well-designed feedforward control can effectively compensate the reference-induced tracking error. To achieve excellent tracking performance such as nanometer accuracy regardless of reference variations, an integrated model-data-based zero-phase error tracking feedforward control (ZPETFC) strategy is synthesized for precision motion systems with complex and nonminimum phase (NMP) dynamics. The feedforward controller comprises a conventional ZPETFC controller and a gain compensation filter structured with symmetric finite impulse response (FIR) filter. Especially, the conventional ZPETFC is predesigned based on the plant model, and consequently, the feedforward controller is parameterized by the gain compensation filter coefficients, which results in excellent capacity for approximating the inverse behavior of the complex and NMP dynamics. In order to compensate the modeling error in the conventional ZPETFC design and improve the tracking performance, a data-based instrumental-variable method with impulse response experiment is developed to obtain the optimal parameter vector under the existence of noise and disturbances. Furthermore, the ridge estimate method using singular value decomposition is employed to guarantee a fast convergent iteration in the case of ill-conditioned Hessian matrix. The proposed ZPETFC strategy enables a convex optimization procedure with the inherent stability in the iterative tuning process, and is finally implemented on a developed ultraprecision wafer stage. Comparative experimental results demonstrate that the strategy is insensitive to reference variations in comparison with iterative learning control, and outperforms preexisting model-based ZPETFC and data-based FIR feedforward control.
Auteurs: Min Li;Yu Zhu;Kaiming Yang;Chuxiong Hu;Haihua Mu;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4139 - 4149
Editeur: IEEE
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» An Internal Crown Geometric Model for Conifer Species Classification With High-Density LiDAR Data
Résumé:
The knowledge of the tree species is a crucial information that governs the success of precision forest management practice. High-density small footprint multireturn airborne light detection and ranging (LiDAR) scanning can collect a huge amount of point samples containing structural details of the forest vertical profile, which can reveal important structural information of the forest components. LiDAR data have been successfully used to distinguish between coniferous and deciduous/broadleaved tree species. However, species classification within a class (e.g., the conifer class) using LiDAR data is a challenging problem when considering the tree external crown characteristics only. This paper presents a novel method for conifer species classification based on the use of geometric features describing both the internal and external structures of the crown. The internal crown geometric features (IGFs) are defined based on a novel internal branch structure model, which uses 3-D region growing and principal component analysis to delineate the branch structure of a conifer tree accurately. IGFs are used together with external crown geometric features to perform conifer species classification. Three different support vector machines have been considered for classification performance evaluation. The experimental analysis conducted on high-density LiDAR data acquired over a portion of the Trentino region in Italy proves the effectiveness of the proposed method.
Auteurs: Aravind Harikumar;Francesca Bovolo;Lorenzo Bruzzone;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2924 - 2940
Editeur: IEEE
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» An Investigation of Electrical and Dielectric Parameters of Sol–Gel Process Enabled $beta $ -Ga2O3 as a Gate Dielectric Material
Résumé:
In this paper, $beta $ -Ga2O3 thin films were grown on a p-Si substrate using the sol–gel method. Structural characterization of the films was performed using X-ray diffraction. Electrical parameters such as breakdown field, interface traps density ( ${D}_{text {it}}$ ), and series resistance ( ${R}_{s}$ ) were investigated at room temperature. The interface trap density was found to be $10^{12}$ eV $^{-1}$ cm $^{-2}$ using the Hill–Coleman method. This result is valuable for MOS capacitor applications. Dielectric parameters were investigated in the wide frequency range (20 kHz–1 MHz) at room temperature. We observed that these parameters have a strong dependence on frequency and voltage.
Auteurs: Ahmet Kaya;Howard Mao;Jianyi Gao;Rajesh V. Chopdekar;Yayoi Takamura;Srabanti Chowdhury;M. Saif Islam;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2047 - 2053
Editeur: IEEE
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» An Investigation of Plug-In Electric Vehicle Charging Impact on Power Systems Scheduling and Energy Costs
Résumé:
This paper investigates the impact of plug-in electric vehicle (EV) integration on the power systems scheduling and energy cost. An intermediary entity, the EV aggregator, participates in the market on behalf of the EV owners by optimally self-scheduling under the price-taking approach. Through detailed rolling simulations for a year and different EVs’ penetration scenarios at a large insular power system, this work highlights the different impact of direct and smart charging on power system scheduling and energy costs, the limitations of the price-taking approach, which is widely used in self-scheduling models, and the difference in system value and market value that smart charging adoption creates in restructured markets under the marginal pricing rule.
Auteurs: Stylianos I. Vagropoulos;Georgios A. Balaskas;Anastasios G. Bakirtzis;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1902 - 1912
Editeur: IEEE
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» An On-Chip Bandpass Filter Using a Broadside-Coupled Meander Line Resonator With a Defected-Ground Structure
Résumé:
An on-chip bandpass filter (BPF) is designed and fabricated in a 0.13- $mu text{m}$ SiGe (Bi)-CMOS technology. This BPF consists of a broadside-coupled meander-line resonator (BCMLR) in conjunction with a defected-ground structure (DGS). By simply grounding a BCMLR, the resonator can be converted into a BPF. Further applying a DGS to this BPF, an additional transmission zero can be generated in the high-frequency band. To understand the fundamentals of this design, an $LC$ -equivalent circuit is given for investigation of the transmission zeros and poles. The measured results show that the BPF has a center frequency at 33 GHz with a bandwidth of 18%. The minimum insertion loss is 2.6 dB, while the maximum stopband attenuation is 44 dB. The chip size, excluding the pads, is only 0.038 mm2 ( $0.126times0.3$ mm $^{2}$ ).
Auteurs: Yi Zhong;Yang Yang;Xi Zhu;Eryk Dutkiewicz;Kam Man Shum;Quan Xue;
Apparue dans: IEEE Electron Device Letters
Date publication: 05.-2017, volume: 38, issue:5, pages: 626 - 629
Editeur: IEEE
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» An on-line geographical information system–based condition monitoring system for 11-kv distribution line insulator
Résumé:
Overhead distribution lines can be considered as tributaries of a distribution system, traversing difficult terrain under harsh climatic conditions. Thus, insulators on distribution lines are prone to damage. A damaged insulator causes distortion of the electric field around it, generating leakage currents, which further damage the surface of the insulator, leading eventually to ground faults. Several computer-aided systems have been adopted by electric power utilities for continuous monitoring of the distribution system by distribution control centers (DCC) [1]–[7]. These systems frequently use technologies such as image processing to conduct electrical and physical tests on the distribution lines [8]–[12].
Auteurs: M. Jaya Bharata Reddy;Rounak Meyur;Diptak Pal;C. Krantikumar;D. K. Mohanta;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 05.-2017, volume: 33, issue:3, pages: 26 - 32
Editeur: IEEE
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» An Orbital Angular Momentum-Based In-Band Full-Duplex Communication System and Its Mode Selection
Résumé:
An orbital angular momentum (OAM)-based in-band full-duplex radio system for line-of-sight communications is studied for the first time, where the OAM beams work as the carriers of the bidirectional transmission. The transmit and receive antennas are assumed to be placed along a common beam axis with a tilt angle that induces a misaligned reception, and the self-interferences are modeled as the near-end cross-talks caused by the parasitic harmonic components within the impure transmitting OAM spectrums. Based on this model, we obtain the optimal OAM eigenmode pair, that maximizes the system sum rate when the self-interferences dominate the noise or vice versa. The results are further validated by simulation.
Auteurs: Zhaoyang Zhang;Yuqing Yuan;Ji Cang;Huayang Wu;Xianmin Zhang;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1183 - 1186
Editeur: IEEE
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» An Overview of Dynamic-Linearization-Based Data-Driven Control and Applications
Résumé:
A brief overview on the model-based control and data-driven control methods is presented. The data-driven equivalent dynamic linearization, as a foundational analysis tool of data-driven control methods for discrete-time nonlinear systems, is introduced in detail with motivations and distinct features. The prototype model-free adaptive control schemes by using the dynamic linearization to an unknown nonlinear plant model, as well as the alternative model-free adaptive control methods by using the dynamic linearization to an unknown ideal nonlinear controller, are discussed. Furthermore, the extensions of the dynamic linearization to unknown nonlinear repetitive systems and the corresponding model-free adaptive iterative learning control methods are also overviewed and summarized. This work highlights the characteristics and comments of the different model-free adaptive control schemes in detail to facilitate the understanding of the readers. Finally, some perspectives on data-driven control methods in information-rich age are given.
Auteurs: Zhongsheng Hou;Ronghu Chi;Huijun Gao;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 4076 - 4090
Editeur: IEEE
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» An RF-Powered FDD Radio for Neural Microimplants
Résumé:
We present a radio system that could be used in millimeter-scale wireless neural implants. The system is RF-powered and demonstrates Mbps data rates required for neuromodulation and recording applications. The radio transmits at 58 Mb/s and receives at 2.5 Mb/s maximum data rates. The transceiver uses a duplexer to achieve full-duplex communication via frequency-division duplexing at 1.74 and 1.86 GHz for TX and RX, respectively. The average power consumption of the transmitter is 93 $mu text{W}$ at 58 Mb/s, while that of the receiver is 7.2 $mu text{W}$ at 2.5 Mb/s. The transceiver was fabricated using 40-nm LP CMOS process and occupies 0.8 mm2 of die area. Including the off-chip duplexer, the system occupies 2 $times $ 1.6 $times $ 0.6 mm3.
Auteurs: Yashar Rajavi;Mazhareddin Taghivand;Kamal Aggarwal;Andrew Ma;Ada S. Y. Poon;
Apparue dans: IEEE Journal of Solid-State Circuits
Date publication: 05.-2017, volume: 52, issue:5, pages: 1221 - 1229
Editeur: IEEE
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» An RFID Based Smartphone Proximity Absence Alert System
Résumé:
We present the design, implementation, and evaluation of an RFID-based cellphone anti-lost and anti-theft measure. The cellphone owner is given an audio-visual alert at the very instant of the lost event, and the cellphone deduces the fact that it is away from its owner and executes the safety measures. This is realized by equipping the cellphone with a low-power RFID Reader and tagging the owner with a passive RFID token to determine a private space around him, which spans within 2-10 feet. We prototype an RFID Reader from discrete components under $60 which can transmit 30 dBm with - 78 dBm sensitivity, and can also serve as an educational tool for academic learning. Our system works on automatic, timed, or accelerometer based thresholds. We interface our system with Samsung Galaxy Note2 and develop an Android User Interface. We carry out extensive indoor and outdoor experiments under static and dynamic scenarios to ascertain the Frontal and Angular ranges, energy and power consumption, and memory and computational overheads. Our salient contribution is a twofold probing scheme—a duty cycle approach that economizes battery overhead, mitigates false alarms and scans the tag for multiple times by leveraging the interrogation time and power. We argue that though our design is costly in power budget, it is highly economical on battery energy because of short interrogation cycles. We show that for 17 tag interrogations from 20-24 dBm, our scheme consumes 72.1 to 52.4 percent lower energy than a single Bluetooth device scan. For a fully embedded design, we propose System-on-Chip RFID solutions. We foresee our endeavor as a viable proximity absence detection scheme for short range applications and scenarios.
Auteurs: Muhammad Jawad Hussain;Li Lu;Shan Gao;
Apparue dans: IEEE Transactions on Mobile Computing
Date publication: 05.-2017, volume: 16, issue:5, pages: 1246 - 1257
Editeur: IEEE
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» An SOI-MEMS Piezoelectric Torsional Stage With Bulk Piezoresistive Sensors
Résumé:
This paper presents a micro-electromechanical stage for out-of-plane positioning of microcantilevers designed for atomic force microscopes. The stage produces an out-of-plane displacement using a torsional mechanism that exploits piezoelectric clamped-guided beams as actuators. To measure the torsional displacement of the stage, novel differential piezoresistive sensors are implemented. These sensors feature clamped-guided beams that exploit the bulk piezoresistivity of silicon. Using this sensing concept eliminates the requirement to fabricate highly doped regions on the flexures. An analytical model is provided that describes the sensor’s linearity. The sensor, the microcantilevers, and the mechanical features of the stage are experimentally characterized. The first resonance frequency of the stage is located at 7.8 kHz, and a static out-of-plane displacement of more than 1.2 $mu text{m}$ is obtained. In addition, the piezoresistive sensor captures the dynamics of the stage within a bandwidth of 13 kHz with a $1sigma $ -resolution of 3 nm.
Auteurs: Mohammad Maroufi;S. O. Reza Moheimani;
Apparue dans: IEEE Sensors Journal
Date publication: 05.-2017, volume: 17, issue:10, pages: 3030 - 3040
Editeur: IEEE
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» An SQP Method Combined With Gradient Sampling for Small-Signal Stability Constrained OPF
Résumé:
Small-Signal Stability Constrained Optimal Power Flow (SSSC-OPF) can provide additional stability measures and control strategies to guarantee the system to be small-signal stable. However, due to the nonsmooth property of the spectral abscissa function, existing algorithms solving SSSC-OPF cannot guarantee convergence. To tackle this computational challenge of SSSC-OPF, we propose a Sequential Quadratic Programming (SQP) method combined with gradient sampling for SSSC-OPF. At each iteration of the proposed SQP, the gradient of the spectral abscissa function is randomly sampled at the current iterate and additional nearby points to make the search direction computation effective in nonsmooth regions. The method can guarantee SSSC-OPF is globally and efficiently convergent to stationary points with probability one. The effectiveness of the proposed method is tested and validated on WSCC 3-machine 9-bus system, New England 10-machine 39-bus system, and IEEE 54-machine 118-bus system.
Auteurs: Peijie Li;Junjian Qi;Jianhui Wang;Hua Wei;Xiaoqing Bai;Feng Qiu;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2372 - 2381
Editeur: IEEE
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» An Ultra-Low Power 1.7-2.7 GHz Fractional-N Sub-Sampling Digital Frequency Synthesizer and Modulator for IoT Applications in 40 nm CMOS
Résumé:
This paper introduces an ultra-low power 1.7-2.7-GHz fractional-N sub-sampling digital PLL (SS-DPLL) for Internet-of-Things (IoT) applications targeting compliance with Bluetooth Low Energy (BLE) and IEEE802.15.4 standards. A snapshot time-to-digital converter (TDC) acts as a digital sub-sampler featuring an increased out-of-range gain and without any assistance from the traditional counting of DCO edges, thus further reducing power consumption. With a proposed DCO-divider phase rotation in the feedback path, the impact of the digital-to-time converter’s (DTC’s) non-linearity on the PLL is reduced and improves fractional spurs by at least 8 dB across BLE channels. Moreover, a “variable-preconditioned LMS” calibration algorithm is introduced to dynamically correct the DTC gain error with fractional frequency control word (FCW) down to 1/16384. Fabricated in 40 nm CMOS, the SS-DPLL achieves phase noise performance of −109 dBc/Hz at 1 MHz offset, while consuming a record-low power of 1.19 mW.
Auteurs: Yao-Hong Liu;Johan Van Den Heuvel;Takashi Kuramochi;Benjamin Busze;Paul Mateman;Vamshi Krishna Chillara;Bindi Wang;Robert Bogdan Staszewski;Kathleen Philips;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1094 - 1105
Editeur: IEEE
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» An Unbounded Frequency Detection Mechanism for Continuous-Rate CDR Circuits
Résumé:
A continuous-rate clock and data recovery (CDR) circuit with unbounded frequency detection mechanism is proposed herein. The unbounded frequency detection mechanism combines the digital quadricorrelator frequency detection and subharmonic tone frequency detection techniques. By adopting the unbounded frequency detector, this reference-less CDR circuit has no locking range limitation and provides an automatically bidirectional frequency detection characteristic. In addition, the CDR circuit can detect the frequency-hopping information without an additional transmitted control signal. Based on the proposed frequency detection methodology, a proof-of-concept CDR circuit is implemented to demonstrate the feasibility and effectiveness of the proposed design.
Auteurs: Yen-Long Lee;Soon-Jyh Chang;Yen-Chi Chen;Yu-Po Cheng;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 500 - 504
Editeur: IEEE
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» An Upgraded ACA Algorithm in Complex Field and Its Statistical Analysis
Résumé:
An upgraded adaptive cross approximation (U-ACA) algorithm in complex field is proposed, including detailed discussion about both relative-error estimator and pivoting threshold. Two new relative-error estimators are constructed, and the range of the pivoting threshold is determined theoretically. Besides, a statistical analysis of the U-ACA algorithm for computational electromagnetics is provided to identify the credibility of existing relative-error estimators and new ones. The statistical experiments show that the U-ACA algorithm with either of the two new relative-error estimators is a more robust algorithm at present for applications in computational electromagnetics, compared with the previous ACA algorithm.
Auteurs: Hou-Xing Zhou;Guang-Yu Zhu;Wei-Bin Kong;Wei Hong;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2734 - 2739
Editeur: IEEE
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» Analysis and Design of VCO-Based Phase-Domain $Sigma Delta $ Modulators
Résumé:
VCO-based phase-domain $Sigma Delta $ modulators employ the combination of a voltage-controlled-oscillator (VCO) and an up/down counter to replace the analog loop filter used in conventional $Sigma Delta $ modulators. Thanks to this highly digital architecture, they can be quite compact, and are expected to shrink even further with CMOS scaling. This paper describes the analysis and design of such converters. Trade-offs between design parameters and the impact of non-idealities, such as finite counter length and VCO non-linearity, are assessed through both theoretical analysis and behavioral simulations. The proposed design methodology is applied to the design of a phase-to-digital converter in a 40-nm CMOS process, which is used to digitize the output of a thermal-diffusivity temperature sensor, achieving ± 0.2° ( $3sigma $ ) phase inaccuracy from -40 to 125 °C and a sensor-limited resolution of 57 m° (RMS) within a 500-Hz bandwidth. Measurements on the prototype agree quite well with theoretical predictions, thus demonstrating the validity of the proposed design methodology.
Auteurs: Uğur Sönmez;Fabio Sebastiano;Kofi A. A. Makinwa;
Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers
Date publication: 05.-2017, volume: 64, issue:5, pages: 1075 - 1084
Editeur: IEEE
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» Analysis Method of Mobile Phone Batteries Remaining State of Charge
Résumé:
The cell phone is among the electronics which have quickly attracted consumers throughout the world with an average usage time of a year and a half, generating with this, a considerable environmental impact. This paper presents a literature review on components of batteries, important factors in battery performance, state of charging and health determination. In this study, through the unloading constant current CC test, it was possible to obtain, in a fast and efficient way, the amount of energy remaining and the state of charge from the lithium-ion mobile batteries discarded by the population, showing that many of the discarded batteries could still be reused as an energy source.
Auteurs: Eduardo Luis Schneider;Rodolfo de Freitas Valle Dresch;Luiz Tiaraju dos Reis Loureiro;Renato Machado de Brito;
Apparue dans: IEEE Latin America Transactions
Date publication: 05.-2017, volume: 15, issue:5, pages: 854 - 860
Editeur: IEEE
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» Analysis of Dynamic Processes in Single-Cell Electroporation and Their Effects on Parameter Selection Based on the Finite-Element Model
Résumé:
Pulsed electric fields have recently been the focus of considerable attention because of their potential application in biomedicine. However, their practical clinical applications are limited by poor understanding of the interaction mechanism between pulsed electric fields and cells, particularly in the process of electroporation and its effect on parameter selection. This paper established a multishelled dielectric model based on finite elements to simulate and analyze the processes involved in electroporation. In particular, the processes include the dynamic development of the pore radius and electroporation region: the distribution of recoverable, nonrecoverable, and nonelectroporation areas on the cell; and the influence of pulse parameters on varying degrees of electroporation. Results showed that membrane conductivity, pore density, transmembrane potential, and distribution of pore radii are functions of time and position on the cell. The electroporation areas were divided into recoverable, nonrecoverable, and no-electroporation pores. For $10~mu text{s}$ , 1.5-kV/cm pulse was observed in the regions exposed to sufficiently high transmembrane voltage (1 V), electroporation occurred, membrane conductivity and pore density (up to $10^{mathrm {16}}/text{m}^{mathrm {2}})$ rapidly increased with time, and electroporation areas increased gradually and were mainly distributed in the range 0°–70° (recoverable pore [0°, 35°], nonrecoverable pore [35°, 70°], and no-electroporation pore [70°, 90°]). Electric field strength was the major factor that induced electroporation, particularly in the recoverable pore, but it had minimal effect on pore- expansion. However, pulse duration affects the nonrecoverable pore, such that the high-intensity wide pulse is more useful in the field of irreversible electroporation. The high-intensity short pulse can increase permeability and maintain cell viability.
Auteurs: Chenguo Yao;Hongmei Liu;Yajun Zhao;Yan Mi;Shoulong Dong;Yanpeng Lv;
Apparue dans: IEEE Transactions on Plasma Science
Date publication: 05.-2017, volume: 45, issue:5, pages: 889 - 900
Editeur: IEEE
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» Analysis of Metasurfaces at Oblique Incidence
Résumé:
The theory of analytical modeling of periodic metasurfaces for normal incidence is extended to the general oblique case. The metasurface is considered as a periodic planar array with electrically small dipolar scatterers. The induced polarization currents are calculated by combining the information obtained from the response of individual scatterer to the incident wave and the interaction of scatterers with each other. All required interaction coefficients for the most general analysis of metasurfaces are analytically derived. The expressions in terms of the polarization currents are presented for the reflected/transmitted fields from metasurfaces at oblique illumination. Although theoretically known that adding normal polarization currents to the tangential ones will not provide extra degrees of freedom in the manipulation of the reflection and transmission properties of metasurfaces, in most practical applications, it is required to consider both tangential as well as normal polarization currents. Thus, the effect of oblique illumination in the modification of normal and tangential polarization currents is clarified. Our theory is used to analyze two canonical examples of bianisotropic metasurfaces composed of chiral and omega inclusions. The results of this paper provide an effective tool to push the analysis as well as the synthesis of metasurfaces one step forward.
Auteurs: Mohammad Yazdi;Mohammad Albooyeh;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2397 - 2404
Editeur: IEEE
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» Analysis of Proportional Fair Scheduling Under Bursty On-Off Traffic
Résumé:
Proportional fair scheduling (PFS) has been adopted as a standard solution for fair resource allocation in modern wireless cellular networks. With the emergence of heterogeneous networks with widely varying user loads, it is of great importance to characterize the performance of PFS under bursty traffic, which is the case in most wireless streaming and data transfer services. In this letter, we provide the first analytical solution to the performance of PFS under bursty on-off traffic load. We use the Gaussian approximation model to derive a closed-form expression of the achievable user data rates. In order to further improve the accuracy of our baseline analytical solution for multi-cell networks, we design a hybrid approximation by employing multi-interference analysis. The simulation results verify that our model guarantees extremely low data rate estimation error, which is further insensitive to changes in session duration, traffic load and user density.
Auteurs: Fei Liu;Janne Riihijärvi;Marina Petrova;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1175 - 1178
Editeur: IEEE
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» Analysis of Recurrent Neural Networks for Probabilistic Modeling of Driver Behavior
Résumé:
The validity of any traffic simulation model depends on its ability to generate representative driver acceleration profiles. This paper studies the effectiveness of recurrent neural networks in predicting the acceleration distributions for car following on highways. The long short-term memory recurrent networks are trained and used to propagate the simulated vehicle trajectories over 10-s horizons. On the basis of several performance metrics, the recurrent networks are shown to generally match or outperform baseline methods in replicating driver behavior, including smoothness and oscillatory characteristics present in real trajectories. This paper reveals that the strong performance is due to the ability of the recurrent network to identify recent trends in the ego-vehicle's state, and recurrent networks are shown to perform as, well as feedforward networks with longer histories as inputs.
Auteurs: Jeremy Morton;Tim A. Wheeler;Mykel J. Kochenderfer;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1289 - 1298
Editeur: IEEE
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» Analysis of Spectral and Energy Efficiency Tradeoff in Single-Line Rate WDM Links
Résumé:
This paper investigates, through simulations, the tradeoff between energy efficiency (EE) and the overall spectral efficiency (SE) of fiber optic links for a given capacity and a link length. The comparison is made for various modulation formats, span lengths, and with/without using forward error correction (FEC). The power consumption of the different system components is estimated from the data sheets of the state-of-the-art equipment. Results show that the use of long single-mode fiber spans (i.e., more than 40 km) improves EE when coherent modulation formats are used. However, with noncoherent formats, the span length must be selected depending on SE, aggregated traffic amount needs to be transmitted, and link length. For almost all modulation formats, FEC reduces the overall energy consumption despite being one of the main power consumers in fiber optic communication systems. The power consumption of 3Rs becomes particularly important when the linear crosstalk limits the system reach. In all other cases, the power consumption of transponders and optical line amplifiers is dominating, but their contribution changes depending on the aggregated traffic amount and system reach.
Auteurs: Aleksejs Udalcovs;Richard Schatz;Lena Wosinska;Paolo Monti;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1847 - 1857
Editeur: IEEE
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» Analysis of Subchannel Correlation in Dual-Polarised MIMO Systems via a Polarisation Diversity Scheme
Résumé:
A polarisation diversity combing scheme for dual-polarised multiple-input and multiple-output channels in small cell environments introduced and evaluated. The scheme is based on post analysis of channel measurement data captured from scenarios and includes indoor-to-indoor, indoor-to-outdoor, and indoor–outdoor–indoor propagation. An analysis of link signal strength and correlation with respect to frequency and polarisation revealed profound differences between copolarised and cross-polarised links in terms of received signal strength and correlation between frequencies. Utilizing these differences, a polarisation diversity combing scheme is evaluated which is shown to produce an average of 10.6-dB polarisation diversity gain.
Auteurs: Cheng Fang;Enjie Liu;Masood Ur Rehman;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 05.-2017, volume: 65, issue:5, pages: 2635 - 2644
Editeur: IEEE
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» Analysis of Zeros in a Boost DC–DC Converter: State Diagram Approach
Résumé:
This brief presents the analysis of zeros present in boost dc–dc converters that are operating in continuous inductor current mode. It proposes the utilization of the concept of multiple forward pathways from input to output to analyze the origin of the resulting zeros and determine their locations. This brief provides insight into the various zeros present in the boost converter through a state diagram approach.
Auteurs: Vikas Paduvalli;R. J. Taylor;Poras T. Balsara;
Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs
Date publication: 05.-2017, volume: 64, issue:5, pages: 550 - 554
Editeur: IEEE
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» Analysis on Special Protection Scheme of Korea Electric Power System by Fully Utilizing STATCOM in a Generation Side
Résumé:
Increase in power demand has required providing infrastructure, such as huge power plants and transmission lines. However, the recent trends in power system planning and operation are being toward maximum utilization of existing electricity infrastructure with tight operating margins because of new constraints placed by economic, political, and environmental issues. This might cause serious stability problems when a severe fault or a sudden outage of critical lines occurs. Therefore, the special protection scheme (SPS) has been used by generator tripping and successive load shedding to prevent a large-scale blackout by the cascading effect. If the number of tripping generators in the SPS operation is reduced, the enormous cost of power outage can be saved. This paper analyzes the enhancement of SPS via the transient stability improvement by the static synchronous compensator (STATCOM) applied to a generation side of Korea electric power system. First, its characteristic related to the SPS is described. Then, the proper capacity of STATCOM is determined with the equal area criterion to reduce the number of tripping generators. Also, the new control method for STATCOM is proposed for its full utilization. Finally, its effectiveness is verified by the case study with the practical data of Korea electric power system.
Auteurs: Dong-Hee Choi;Soo Hyoung Lee;Yong Cheol Kang;Jung-Wook Park;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 1882 - 1890
Editeur: IEEE
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» Analytic $JV$ -Characteristics of Ideal Intermediate Band Solar Cells and Solar Cells With Up and Downconverters
Résumé:
The ideal diode equation is regularly used to describe the $textit {JV}$ -characteristic of single junction solar cells. The connection between the diode equation and fundamental physics is the application of the Boltzmann approximation to describe the fluxes of photons emitted by the cell. In this paper, this approximation is used to derive analytic $textit {JV}$ -characteristics for three photovoltaic high-efficiency concepts, intermediate band solar cells, and solar cells optically coupled to up and downconverters. These three concepts share the common feature that they allow excitation of electrons between at least three energy levels, which assures a better utilization of the solar spectrum and leads to limiting efficiencies surpassing the Shockley–Queisser limit. Although being considerablysimpler to implementand use, the resulting $textit {JV}$ -characteristics reproduce the limiting efficiencies obtained from full detailed balancemodels. The simplicity facilitates the intuitive understanding of such devices. The presented models also have the potential to serve as a useful framework for further modeling, through savings in computation time and complexity.
Auteurs: Rune Strandberg;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2275 - 2282
Editeur: IEEE
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» Analytic Approximations for Real-Time Area Light Shading
Résumé:
We introduce analytic approximations for accurate real-time rendering of surfaces lit by non-occluded area light sources. Our solution leverages the Irradiance Tensors developed by Arvo for the shading of Phong surfaces lit by a polygonal light source. Using a reformulation of the 1D boundary edge integral, we develop a general framework for approximating and evaluating the integral in constant time using simple peak shape functions. To overcome the Phong restriction, we propose a low cost edge splitting strategy that accounts for the spherical warp introduced by the half vector parametrization. Thanks to this novel extension, we accurately approximate common microfacet BRDFs, providing a practical method producing specular stretches that closely match the ground truth in real-time. Finally, using the same approximation framework, we introduce support for spherical and disc area light sources, based on an original polygon spinning method supporting non-uniform scaling operations and horizon clipping. Implemented on a GPU, our method achieves real-time performances without any assumption on area light shape nor surface roughness.
Auteurs: Pascal Lecocq;Arthur Dufay;Gaël Sourimant;Jean-Eudes Marvie;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1428 - 1441
Editeur: IEEE
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» Analytic Modeling for Nanoscale Resistive Filament Variation in ReRAM With Stochastic Differential Equation
Résumé:
Nanoscale filament is the active area in oxygen vacancy type resistance random access memory (ReRAM), which is formed stochastically during electric test after being fabricated in a clean room. That is, the filament dimension cannot be controlled with a designed mask pattern. Here, we introduce a formula to describe the current cycle-to-cycle trajectories based on a stochastic differential equation (SDE) with microscopic structure parameters: filament dimension and oxygen vacancy concentration. Since ReRAM conduction follows hopping, the filament can be described by a random resistance network (RRN). The stochastic configuration of an RRN follows the Brownian motion, which is the key parameter in the diffusion of SDE. The formula provides a practically quantitative filament characterization method, which is verified by direct observation of the filament in actual devices. Based on the formula, we can predict ReRAM endurance with the given microscopic structure parameters.
Auteurs: Zhiqiang Wei;Koji Eriguchi;
Apparue dans: IEEE Transactions on Electron Devices
Date publication: 05.-2017, volume: 64, issue:5, pages: 2201 - 2206
Editeur: IEEE
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» Analytical and Experimental Investigations on Mitigation of Interference in a DBF MIMO Radar
Résumé:
As driver assistance systems and autonomous driving are on the rise, radar sensors become a common device for automobiles. The high sensor density leads to the occurrence of interference, which decreases the detection capabilities. Here, digital beamforming (DBF) is applied to mitigate such interference. A DBF system requires a calibration of the different receiving channels. It is shown how this calibration completely changes the DBF beam pattern required to cancel interferences, if the system has no IQ receiver. Afterward, the application of DBF on a multiple-input multiple-output (MIMO) radar is investigated. It is shown that only the real aperture and not the virtual one can be used for interference suppression, leading to wide notches in the pattern. However, for any target the large virtual aperture can be exploited, even if interferers are blinded out. Moreover, the wide notches for interference suppression of the real aperture appear narrow in the virtual aperture for target localization. The results are verified by measurements with time-multiplexing MIMO radar.
Auteurs: Jonathan Bechter;Muhammad Rameez;Christian Waldschmidt;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 05.-2017, volume: 65, issue:5, pages: 1727 - 1734
Editeur: IEEE
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» Analytical Expressions for Joint Distributions in Probabilistic Load Flow
Résumé:
Adopting the Gaussian mixture model, we derive an analytical expression for the joint probability density function of active power on multiple transmission lines, in the presence of non-Gaussian stochastic power injections. The corresponding joint cumulative distribution function is further obtained by multiple integrals. Results of the proposed method coincide with that of Monte Carlo simulations.
Auteurs: Zhiwen Wang;Chen Shen;Feng Liu;Feng Gao;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 05.-2017, volume: 32, issue:3, pages: 2473 - 2474
Editeur: IEEE
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» Analytical Model of Mid-Infrared Surface Plasmon Modes in a Cylindrical Long-Range Waveguide With Double-Layer Graphene
Résumé:
An optical waveguide for working in mid-infrared range is highly desirable. However, such a waveguide is required to yield a long propagation distance and deep subwavelength confinement. Although the graphene-based surface plasmon polariton (SPP) waveguides have exhibited some potential in this regard, their propagation lengths are currently insufficient (∼100 μm). In this paper, we propose a graphene-based cylindrical long-range SPP (LRSPP) waveguide, which is composed of a cylindrical silicon nanowire core surrounded by an inner graphene layer, a silica layer, and an outer graphene layer from inside to out. First, the electromagnetic field equation and the dispersion equation of this waveguide are derived. Then, combining these derived equations with the numerical simulation, the propagation properties of the LRSPP and the short-range SPP modes are analyzed. The results show that the proposed waveguide with the LRSPP fundamental mode has a notable advantage for simultaneously achieving a larger propagation length (∼10 μm) and a deep subwavelength confinement ( $sim10^{- 5},A_{0}$, where $A_{0}$ is the diffraction-limited mode area). This waveguide has potential for application in high-density photonic integrated circuits in the mid-infrared range.
Auteurs: Jian-Ping Liu;Xiang Zhai;Fang Xie;Ling-Ling Wang;Sheng-Xuan Xia;Hong-Ju Li;Xin Luo;Xiong-Jun Shang;
Apparue dans: Journal of Lightwave Technology
Date publication: 05.-2017, volume: 35, issue:10, pages: 1971 - 1979
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Analytical Prediction of Magnetic Field Distribution in Spoke-Type Permanent-Magnet Synchronous Machines Accounting for Bridge Saturation and Magnet Shape
Résumé:
This paper presents an analytical model for the prediction of magnetic field distribution in spoke-type permanent-magnet synchronous machines with rectangular magnets and magnetic bridges. The influence of saturation is considered. The magnetic bridges are equivalent to fan-shaped saturation regions. On the basis of the same pole-arc angle and identical magnetic energy, one rectangular magnet is simplified to two fan-shaped regions. The entire field domain is divided into eight types of simple subdomains, i.e., shaft, inner magnetic bridge, inner fan-shaped magnet, outer fan-shaped magnet, outer magnetic bridge, air gap, slot opening, and slot. The effect of magnetic field caused by armature reaction on the saturation of magnetic bridges is considered. The analytical expression of each subdomain is derived and the field solution is obtained by the boundary conditions. The analytical results at the no-load and on-load conditions are verified with the finite-element method.
Auteurs: Peixin Liang;Feng Chai;Yi Li;Yulong Pei;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3479 - 3488
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Analytical Rotor Position Estimation for SRM Based on Scaling of Reluctance Characteristics From Torque-Balanced Measurement
Résumé:
In this paper, a novel analytical method is proposed for rotor position estimation of switched reluctance machine (SRM). The nonlinear reluctance characteristic of the SRM is divided into two parts, namely air gap and iron core, and analyzed in detail from the aspect of magnetic field. According to the inherent features of the reluctance characteristic, it is analytically expressed based on scaling. Two segments are considered, which are expressed as a linear function and a quadratic function, respectively. Then, the analytical expressions of rotor position are derived for each segment. The effectiveness of the proposed analytical estimation method is evaluated with detailed simulations and experiments under different operating conditions. The proposed method is accurate and just requires the reluctance characteristic at four or even two rotor positions, which can be conveniently measured by the torque-balanced method.
Auteurs: Shoujun Song;Shuo Chen;Weiguo Liu;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 05.-2017, volume: 64, issue:5, pages: 3524 - 3536
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Analyzing Eye-Tracking Information in Visualization and Data Space: From Where on the Screen to What on the Screen
Résumé:
Eye-tracking data is currently analyzed in the image space that gaze-coordinates were recorded in, generally with the help of overlays such as heatmaps or scanpaths, or with the help of manually defined areas of interest (AOI). Such analyses, which focus predominantly on where on the screen users are looking, require significant manual input and are not feasible for studies involving many subjects, long sessions, and heavily interactive visual stimuli. Alternatively, we show that it is feasible to collect and analyze eye-tracking information in data space. Specifically, the visual layout of visualizations with open source code that can be instrumented is known at rendering time, and thus can be used to relate gaze-coordinates to visualization and data objects that users view, in real time. We demonstrate the effectiveness of this approach by showing that data collected using this methodology from nine users working with an interactive visualization, was well aligned with the tasks that those users were asked to solve, and similar to annotation data produced by five human coders. Moreover, we introduce an algorithm that, given our instrumented visualization, could translate gaze-coordinates into viewed objects with greater accuracy than simply binning gazes into dynamically defined AOIs. Finally, we discuss the challenges, opportunities, and benefits of analyzing eye-tracking in visualization and data space.
Auteurs: Sayeed Safayet Alam;Radu Jianu;
Apparue dans: IEEE Transactions on Visualization and Computer Graphics
Date publication: 05.-2017, volume: 23, issue:5, pages: 1492 - 1505
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Anatomical Directional Dissimilarities in Tri-axial Swallowing Accelerometry Signals
Résumé:
Swallowing accelerometry is a noninvasive approach currently under consideration as an instrumental screening test for swallowing difficulties, with most current studies focusing on the swallowing vibrations in the anterior–posterior (A-P) and superior–inferior (S-I) directions. However, the displacement of the hyolaryngeal structure during the act of swallowing in patients with dysphagia involves declination of the medial–lateral (M-L), which suggests that the swallowing vibrations in the M-L direction have the ability to reveal additional details about the swallowing function. With this motivation, we performed a broad comparison of the swallowing vibrations in all three anatomical directions. Tri-axial swallowing accelerometry signals were concurrently collected from 72 dysphagic patients undergoing videofluoroscopic evaluation of swallowing (mean age: 63.94 ± 12.58 years period). Participants swallowed one or more thickened liquids with different consistencies including thin–thick liquids, nectar-thick liquids, and pudding-thick liquids with either a comfortable self-selected volume from a cup or a controlled volume by the examiner from a 5-ml spoon. Swallows were grouped based on the viscosity of swallows and the participant’s stroke history. Then, a comprehensive set of features was extracted in multiple signal domains from 881 swallows. The results highlighted inter-axis dissimilarities among tri-axial swallowing vibrations including the extent of variability in the amplitude of signals, the degree of predictability of signals, and the extent of disordered behavior of signals in time-frequency domain. First, the upward movement of the hyolaryngeal structure, representing the S-I signals, were actually more variable in amplitude and showed less predictable behavior than the sideways and forward movements, representing the A-P and M-L signals, duri- g swallowing. Second, the S-I signals, which represent the upward movement of the hyolaryngeal structure, behaved more disordered in the time-frequency domain than the sideways movement, M-L signals, in all groups of study except for the pudding swallows in the stroke group. Third, considering the viscosity and the participant’s pathology, thin liquid swallows in the nonstroke group presented the most directional differences among all groups of study. In summary, despite some directional dissimilarities, M-L axis accelerometry characteristics are similar to those of the two other axes. This indicates that M-L axis characteristics, which cannot be observed in videofluoroscopic images, can be adequately derived from the A-P and S-I axes.
Auteurs: Faezeh Movahedi;Atsuko Kurosu;James L. Coyle;Subashan Perera;Ervin Sejdić;
Apparue dans: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Date publication: 05.-2017, volume: 25, issue:5, pages: 447 - 458
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Angled 3D Glass-to-Silicon Photonics Coupling Interface
Résumé:
A numerical study on the design of a novel low-loss, low-cost, and low fabrication complexity, angled 3D Glass-to-SiPh coupling interface is demonstrated. The interface is composed of a 2° angled 3D glass waveguide and a thin-silicon-on-insulator platform flip-chip assembled in close proximity. The overall structure is designed and optimized based on the maximization of the coupling strength ( $kappa )$ as well as the calculation of a constant loss taper (CLT) silicon taper. The reported maximum conversion efficiency is 85.7% for 1.55- $mu text{m}$ central wavelength and is almost flat across the entire $C$ -band. The results were obtained using a 3D eigenmode expansion (3D-EME) propagation solver and were verified through the 3D finite-difference time-domain (3D-FDTD) simulation method.
Auteurs: G. Poulopoulos;D. Kalavrouziotis;J. R. Macdonald;P. Mitchell;N. Psaila;H. Avramopoulos;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 05.-2017, volume: 29, issue:9, pages: 763 - 766
Editeur: IEEE
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» Anomaly Detection in Traffic Scenes via Spatial-Aware Motion Reconstruction
Résumé:
Anomaly detection from a driver's perspective when driving is important to autonomous vehicles. As a part of Advanced Driver Assistance Systems (ADAS), it can remind the driver about dangers in a timely manner. Compared with traditional studied scenes such as a university campus and market surveillance videos, it is difficult to detect an abnormal event from a driver's perspective due to camera waggle, abidingly moving background, drastic change of vehicle velocity, etc. To tackle these specific problems, this paper proposes a spatial localization constrained sparse coding approach for anomaly detection in traffic scenes, which first measures the abnormality of motion orientation and magnitude, respectively, and then fuses these two aspects to obtain a robust detection result. The main contributions are threefold, as follows. 1) This work describes the motion orientation and magnitude of the object, respectively, in a new way, which is demonstrated to be better than the traditional motion descriptors. 2) The spatial localization of an object is taken into account considering the sparse reconstruction framework, which utilizes the scene's structural information and outperforms the conventional sparse coding methods. 3) Results of motion orientation and magnitude are adaptively weighted and fused by a Bayesian model, which makes the proposed method more robust and able to handle more kinds of abnormal events. The efficiency and effectiveness of the proposed method are validated by testing on nine difficult video sequences that we captured ourselves. Observed from the experimental results, the proposed method is more effective and efficient than the popular competitors and yields a higher performance.
Auteurs: Yuan Yuan;Dong Wang;Qi Wang;
Apparue dans: IEEE Transactions on Intelligent Transportation Systems
Date publication: 05.-2017, volume: 18, issue:5, pages: 1198 - 1209
Editeur: IEEE
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» Antenna Cross-Polar Requirements for 3-PolD Weather Radar Measurements
Résumé:
The analysis and correction of the bias occurring in weather radar polarimetric measurements is a challenging problem. Polarization coupling due to the cross-polar radiation pattern of the radar's antenna is known to be responsible for errors in the estimation of the polarimetric covariance matrix, and consequently in the hydrometeor classification and quantification, either when using the ATSR or the SHV method. An alternative method for Doppler and polarimetric measurements based on transmitting three different polarizations (3-PolD) has been proven to provide accurate polarimetric covariance matrix estimates without making any hypothesis about the target polarimetric response or its Doppler spectrum. This method does not reduce the Doppler capabilities or the unambiguous range of the radar despite alternately transmitting 3-PolD. These characteristics have encouraged evaluating the polarimetric parameter biases due to cross-polar radiation when this method is used. Biases are calculated considering reflector antenna systems as well as phased-array antenna systems. The results show that this method may guarantee a tolerable bias level even with a poor co- to cross-polar antenna pattern ratio.
Auteurs: José M. Pidre;María Vera Isasa;Verónica Santalla del Río;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 05.-2017, volume: 55, issue:5, pages: 2682 - 2692
Editeur: IEEE
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» Antenna Selection in MIMO Cognitive AF Relay Networks With Mutual Interference and Limited Feedback
Résumé:
This letter studies antenna selection in amplify-and-forward multiple-input multiple-output cooperative cognitive radio system under mutual primary-secondary interference. Two power allocation methods are adopted at the secondary transmitters, assuming perfect and limited feedback from the primary receiver. For both methods, outage, and error performance analysis is conducted, where simple, closed-form expressions are derived over Rayleigh fading channels. In addition, asymptotic analysis is performed to get insights about the diversity gain and the effects of key parameters, including the primary receiver feedback and the number of the antennas. Our analytical results, which are validated with simulations, show the effective impact of the proposed model on enhancing the overall system performance.
Auteurs: Eylem Erdogan;Ali Afana;Salama Ikki;Halim Yanikomeroglu;
Apparue dans: IEEE Communications Letters
Date publication: 05.-2017, volume: 21, issue:5, pages: 1111 - 1114
Editeur: IEEE
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» Application of the Thermal Fin Approximation to Modeling Voice Coil Magnetic Fields and Performance
Résumé:
This paper develops an approximate analytical model to describe the magnetic fluxes, forces, and armature reaction in cylindrical voice coil actuators and related electric machines. Magnetic flux is assumed to either lie in an inner region of the actuator and parallel to its axis, or in an outer region of the actuator and oriented radially. A differential reluctance model is derived for this set of assumptions, with a structure and solution set similar to those involved in extended-surface heat transfer (“fins”) and lossy transmission lines. Particular solutions for the force constant, motor constant, coil inductance, and variable-reluctance force are found for a symmetric motor with opposed axial permanent magnets on either side of an iron flux concentrator. The model results for this topology are validated using finite-element analysis and experimental measurements from a prototype.
Auteurs: Bryan P. Ruddy;
Apparue dans: IEEE Transactions on Magnetics
Date publication: 05.-2017, volume: 53, issue:5, pages: 1 - 8
Editeur: IEEE
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» Application of VPM for Scattering From Tapered Cylindrical Components of Vegetation
Résumé:
To advance the investigation of vegetated terrain using polarimetric remote sensing techniques, it is important to determine the electromagnetic properties of key constituents, such as branches and trunks, which may be realistically modeled by tapered cylinders. To this end, we apply our previously proposed virtual partition method (VPM). Numerical simulations demonstrate that VPM possesses the desired features, such as high fidelity prediction of the scattering amplitude function and fulfillment of energy conservation as well as the reciprocity theorem. It thus may be helpful in the pursuit of better coherent scattering models of vegetated terrain, a finer understanding of PolInSAR imagery, and a better characterization of scattering mechanisms.
Auteurs: Chao Yang;Yang Du;
Apparue dans: IEEE Geoscience and Remote Sensing Letters
Date publication: 05.-2017, volume: 14, issue:5, pages: 654 - 658
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Apply or Die: On the Role and Assessment of Application Papers in Visualization
Résumé:
Application-oriented papers provide an important way to invigorate and cross-pollinate the visualization field, but the exact criteria for judging an application paper's merit remain an open question. This article builds on a panel at the 2016 IEEE Visualization Conference entitled "Application Papers: What Are They, and How Should They Be Evaluated?" that sought to gain a better understanding of prevalent views in the visualization community. This article surveys current trends that favor application papers, reviews the benefits and contributions of this paper type, and discusses their assessment in the review process. It concludes with recommendations to ensure that the visualization community is more inclusive to application papers.
Auteurs: Gunther H. Weber;Sheelagh Carpendale;David Ebert;Brian Fisher;Hans Hagen;Ben Shneiderman;Anders Ynnerman;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 05.-2017, volume: 38, issue:3, pages: 96 - 104
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Approximate MMSE Estimator for Linear Dynamic Systems With Gaussian Mixture Noise
Résumé:
In this work, we propose an approximate minimum mean-square error filter for linear dynamic systems with Gaussian Mixture (GM) noise. The proposed estimator tracks each component of the GM posterior with an individual filter and minimizes the trace of the covariance matrix of the bank of filters, as opposed to minimizing the MSE of individual filters filters in the commonly used Gaussian sum filter (GSF). Hence, the spread of means in the proposed method is smaller than that of GSF which makes it more robust to removing components. Consequently, reduction schemes with lower computational complexity can be used with the proposed filter without losing estimation accuracy and precision. This is supported through simulations on synthetic data as well as experimental data related to an indoor localization system. Additionally, we show that in two limit cases the state estimation provided by our proposed method converges to that of GSF, and we provide simulation results supporting this in other cases.
Auteurs: Leila Pishdad;Fabrice Labeau;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 05.-2017, volume: 62, issue:5, pages: 2457 - 2463
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Arc Fault Detection Method Based on CZT Low-Frequency Harmonic Current Analysis
Résumé:
This paper presents a method for the detection of series arc faults in electrical circuits, which has been developed starting from an experimental characterization of the arc fault phenomenon and an arcing current study in several test conditions. Starting from this, the authors have found that is it possible to suitably detect arc faults by means of a high-resolution low-frequency harmonic analysis of current signal, based on chirp zeta transform, and a proper set of indicators. The proposed method effectiveness is shown by means of experimental tests, which were carried in both arcing and nonarcing conditions and in the presence of different loads, chosen according to the UL 1699 standard requirements.
Auteurs: Giovanni Artale;Antonio Cataliotti;Valentina Cosentino;Dario Di Cara;Salvatore Nuccio;Giovanni Tinè;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 05.-2017, volume: 66, issue:5, pages: 888 - 896
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Arc-Flash Mitigation: A Systematic Approach for Company Standard Power System Schemes
Résumé:
Arc-flash hazard assessment studies involving a very large oil and gas company's equipment rated 38 kV and below revealed locations with excessive arcflash incident energy. After conducting many additional studies of power distribution systems for various plants (e.g., refineries, gas plants, gas-oil separation plants, and natural gas liquid plants), we realized that dangerous locations (greater than 40 cal/cm<sup>2</sup>) are somewhat consistent among various plant types. This knowledge makes planning and budgeting for implementing arc-flash mitigation predictable from a corporate perspective. Specific arc-flash mitigation techniques can be embedded in the specifications of new projects as well as company material standards to avoid unnecessary retrofit activities after installation. Maintenance personnel can also be effectively trained on arc-flash mitigation and safe work practices when consistent solutions are implemented. This article demonstrates a systematic approach to address dangerous arc-flash locations for corporate planning purposes and provides practical mitigation solutions that can be applied at many company facilities.
Auteurs: Rakan El-Mahayni;Jamal Bugshan;Ritchie Pragale;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 05.-2017, volume: 23, issue:3, pages: 24 - 32
Editeur: IEEE
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» Are There Many Real Innovators Nowadays?
Résumé:
Academia struggles to produce innovative work leading to highimpact publications. In the meantime, the goal of every researcher is to make as significant an impact as is possible, gauged mainly by a high number of citations. Another parameter is the visibility of the conferences or journals that researchers choose to publish their findings.
Auteurs: Vasileios Theodosiadis;
Apparue dans: IEEE Potentials
Date publication: 05.-2017, volume: 36, issue:3, pages: 41 - 43
Editeur: IEEE
Document complet vers site de l'éditeur
 


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