###### Accueil » Publications dans le domaines des technologies » 06-2017
 Pages: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
 Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 06-2017 trié par par titre, page: 0
» "What Do You Do" [From the Editor's Desk]
 Résumé:Presents the introductory editorial for this issue of the publication. Auteurs: Alfy Riddle; Apparue dans: IEEE Microwave Magazine Date publication: 06.-2017, volume: 18, issue:4, pages: 6 - 12 Editeur: IEEE Document complet vers site de l'éditeur
» $K$ -Band Phase Discriminator Using Multiport Downconversion for Monopulse Tracker
 Résumé:In this letter, K-band phase discriminator based on multiport downconversion for monopulse tracking system is presented. The proposed architecture adopts multiple six-port junctions to individually process elevation and azimuth difference signals delivered from a multibeam antenna feed network. To produce accurate 2-D angular information, elevation and azimuth difference channel path calibration by reflection-type phase shifters and attenuators are also used. The proposed hybrid multiport junction was implemented with microstrip passive circuits and GaAs monolithic microwave integrated circuits. The performance was verified at the satellite downlink frequency of 20 GHz by successful generations of quadrature I/Q signals according to elevation or azimuth difference signal variations. Auteurs: Seong-Mo Moon;In-Bok Yom;Han Lim Lee; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 06.-2017, volume: 27, issue:6, pages: 599 - 601 Editeur: IEEE Document complet vers site de l'éditeur
» $L_{1}$ -Regularization-Based SAR Imaging and CFAR Detection via Complex Approximated Message Passing
 Résumé:Synthetic aperture radar (SAR) is a widely used active high-resolution microwave imaging technique that has alltime and all-weather reconnaissance ability. Compared with traditionally matched filtering (MF)-based methods, Lq(0 ≤ q ≤ 1) regularization technique can efficiently improve SAR imaging performance e.g., suppressing sidelobes and clutter. However, conventional Lq-regularization-based SAR imaging approach requires transferring the 2-D echo data into a vector and reconstructing the scene via 2-D matrix operations. This leads to significantly more computational complexity compared with MF, and makes it very difficult to apply in high-resolution and wide-swath imaging. Typical Lq regularization recovery algorithms, e.g., iterative thresholding algorithm, can improve imaging performance of bright targets, but not preserve the image background distribution well. Thus, image background statistical-property-based applications, such as constant false alarm rate (CFAR) detection, cannot be applied to regularization recovered SAR images. On the other hand, complex approximated message passing (CAMP), an iterative recovery algorithm for L1 regularization reconstruction, can achieve not only the sparse estimation of the original signal as typical regularization recovery algorithms but also a nonsparse solution simultaneously. In this paper, two novel CAMP-based SAR imaging algorithms are proposed for raw data and complex radar image data, respectively, along with CFAR detection via the CAMP recovered nonsparse result. The proposed method for raw data can not only improve SAR image performance as conventional L1 regularization technique but also reduce the computational cost efficiently. While only when we have MF recovered SAR complex image rather than raw data, the proposed method for complex image data can achieve a similar reconstructed image quality as the regularization-ba- ed SAR imaging approach using the full raw data. The most important contribution of this paper is that the proposed CAMP-based methods make CFAR detection based on the regularization reconstruction SAR image possible using their nonsparse scene estimations, which has a similar background statistical distribution as the MF recovered images. The experimental results validated the effectiveness of the proposed methods and the feasibility of the recovered nonsparse images being used for CFAR detection. Auteurs: Hui Bi;Bingchen Zhang;Xiao Xiang Zhu;Wen Hong;Jinping Sun;Yirong Wu; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 06.-2017, volume: 55, issue:6, pages: 3426 - 3440 Editeur: IEEE Document complet vers site de l'éditeur
» $T$ – $\Omega$ Formulation for Eddy-Current Problems with Periodic Boundary Conditions
 Résumé:This paper presents a novel technique to perform the topological pre-processing needed in formulations based on an electric vector potential and a magnetic scalar potential when the eddy-current problem being solved is subject to periodic boundary conditions. In this case, in fact, all the techniques to produce the generators for the first cohomology group introduced in the literature cannot be used directly on the input mesh. The novel technique is very fast and it is used to model cables for power delivery. Auteurs: Paolo Bettini;Roberto Benato;Sebastian Dambone Sessa;Ruben Specogna; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» $V$ -Band Waveguide Microcalorimeter for Millimeter-Wave Power Standards
 Résumé:This paper describes a recently developed V-band waveguide microcalorimeter that serves as primary power standards at the Korea Research Institute of Standards and Science (KRISS). The design scheme of the waveguide microcalorimeter is presented, and its basic performance is evaluated. The stability of the thermopile module of the microcalorimeter at ambient temperature is measured, and appropriate parameters obtained from a linear modeling are employed to compensate the temperature drift. The thermal performance of an adiabatic waveguide is simulated using a finite-element-method-based tool. A dedicated high-power V-band source module is developed, and its stability and repeatability are evaluated. In order to determine the correction factor of the microcalorimeter, the offset-short method was used and the results are presented. The uncertainty budget of a V-band reference standard at selected frequencies is presented. Auteurs: Jae-Yong Kwon;Tae-Weon Kang;No-Weon Kang; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 06.-2017, volume: 66, issue:6, pages: 1598 - 1604 Editeur: IEEE Document complet vers site de l'éditeur
» $\beta$ -Ga2O3 MOSFETs for Radio Frequency Operation
 Résumé:We demonstrate a $\beta$ -Ga2O3 MOSFET with record-high transconductance ( ${g}_{m}$ ) of 21 mS/mm and extrinsic cutoff frequency ( ${f}_{T}$ ) and maximum oscillating frequency ( ${f}_{\max }$ ) of 3.3 and 12.9 GHz, respectively, enabled by implementing a new highly doped ohmic cap layer with a sub-micron gate recess process. RF performance was further verified by CW Class-A power measurements with passive source and load tuning at 800 MHz, resulting in ${P}_{{OUT}}$ , power gain, and power-added efficiency of 0.23 W/mm, 5.1 dB, and 6.3%, respectively. These preliminary results indicate potential for monolithic or heterogeneous integration of power switch and RF devices using $\beta$ -Ga2O3. Auteurs: Andrew Joseph Green;Kelson D. Chabak;Michele Baldini;Neil Moser;Ryan Gilbert;Robert C. Fitch;Günter Wagner;Zbigniew Galazka;Jonathan Mccandless;Antonio Crespo;Kevin Leedy;Gregg H. Jessen; Apparue dans: IEEE Electron Device Letters Date publication: 06.-2017, volume: 38, issue:6, pages: 790 - 793 Editeur: IEEE Document complet vers site de l'éditeur
» ${H}_{\infty }$-LQR-Based Coordinated Control for Large Coal-Fired Boiler–Turbine Generation Units
 Résumé:The coordinated control system of a boiler–turbine unit plays an important role in maintaining the balance of energy supply and demand, optimizing operational efficiency, and reducing pollutant emissions of the coal-fired power generation unit. The existing challenges (the fast response to wide-scaled load changes, the matching requirements between a boiler and a turbine, and cooperative operation of a large number of distributed devices) make the design of the coordinated controller for the boiler–turbine unit be a tough task. In this paper, based on a typical coal-fired power unit model, using the linear-quadratic regulator (LQR), a coordinated control scheme with $H_{\infty }$ performance is proposed: the $H_{\infty }$ method is used to ensure control performance on the basis of reasonable scheduling of distributed equipment; the LQR is applied to limit the control actions to meet the actuator saturation constraints. Case studies for a practical 500 MW coal-fired boiler–turbine unit model indicate that the designed control system has satisfactory performance in a wide operation range and has a very good boiler–turbine coordination capacity. Auteurs: Le Wei;Fang Fang; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 06.-2017, volume: 64, issue:6, pages: 5212 - 5221 Editeur: IEEE Document complet vers site de l'éditeur
» ${H}_{\infty }$-LQR-Based Coordinated Control for Large Coal-Fired Boiler–Turbine Generation Units
 Résumé:The coordinated control system of a boiler–turbine unit plays an important role in maintaining the balance of energy supply and demand, optimizing operational efficiency, and reducing pollutant emissions of the coal-fired power generation unit. The existing challenges (the fast response to wide-scaled load changes, the matching requirements between a boiler and a turbine, and cooperative operation of a large number of distributed devices) make the design of the coordinated controller for the boiler–turbine unit be a tough task. In this paper, based on a typical coal-fired power unit model, using the linear-quadratic regulator (LQR), a coordinated control scheme with $H_{\infty }$ performance is proposed: the $H_{\infty }$ method is used to ensure control performance on the basis of reasonable scheduling of distributed equipment; the LQR is applied to limit the control actions to meet the actuator saturation constraints. Case studies for a practical 500 MW coal-fired boiler–turbine unit model indicate that the designed control system has satisfactory performance in a wide operation range and has a very good boiler–turbine coordination capacity. Auteurs: Le Wei;Fang Fang; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 06.-2017, volume: 64, issue:6, pages: 5212 - 5221 Editeur: IEEE Document complet vers site de l'éditeur
» ${H}_{\infty }$-LQR-Based Coordinated Control for Large Coal-Fired Boiler–Turbine Generation Units
 Résumé:The coordinated control system of a boiler–turbine unit plays an important role in maintaining the balance of energy supply and demand, optimizing operational efficiency, and reducing pollutant emissions of the coal-fired power generation unit. The existing challenges (the fast response to wide-scaled load changes, the matching requirements between a boiler and a turbine, and cooperative operation of a large number of distributed devices) make the design of the coordinated controller for the boiler–turbine unit be a tough task. In this paper, based on a typical coal-fired power unit model, using the linear-quadratic regulator (LQR), a coordinated control scheme with $H_{\infty }$ performance is proposed: the $H_{\infty }$ method is used to ensure control performance on the basis of reasonable scheduling of distributed equipment; the LQR is applied to limit the control actions to meet the actuator saturation constraints. Case studies for a practical 500 MW coal-fired boiler–turbine unit model indicate that the designed control system has satisfactory performance in a wide operation range and has a very good boiler–turbine coordination capacity. Auteurs: Le Wei;Fang Fang; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 06.-2017, volume: 64, issue:6, pages: 5212 - 5221 Editeur: IEEE Document complet vers site de l'éditeur
» Ε-time early warning data backup in disaster-aware optical inter-connected data center networks
 Résumé:Backup in data center networks (DCNs) against disasters is a critical task for avoiding huge data loss. In this paper, we optimize data backup for a particular DCN node threatened by a disaster by assuming geodistributed optical interconnected DCNs, where the node can be aware of the disaster in an E time before it is disrupted. We first formulate an integer linear program (ILP) to find the maximum amount of data in the threatened DCN node that can be protected. This helps to determine which data should be protected according to data importance. Then we formulate another ILP to achieve minimum-cost backup by properly selecting a set of safe backup DCN nodes and corresponding backup routes. To get real-time solutions for engineering practice, we also propose a heuristic to achieve cost-efficient backup in ε-time early-warning disasters. Extensive numerical results show that the proposed algorithms can automatically adapt to different early warning times E for generating cost-efficient data backup solutions. Auteurs: Lisheng Ma;Wei Su;Bin Wu;Tarik Taleb;Xiaohong Jiang;Norio Shiratori; Apparue dans: IEEE/OSA Journal of Optical Communications and Networking Date publication: 06.-2017, volume: 9, issue:6, pages: 536 - 545 Editeur: IEEE Document complet vers site de l'éditeur
» 2017 Chapter Events [Chapter News]
 Résumé:Presents information on various APS Society chapters. Auteurs: Ajay K. Poddar; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 06.-2017, volume: 59, issue:3, pages: 10 - 98 Editeur: IEEE Document complet vers site de l'éditeur
» 2017 IEEE Fellows Elevation and Recognition
 Résumé:Presents MMTS Society members who were elevated to the status of IEEE Fellow. Auteurs: Alfy Riddle; Apparue dans: IEEE Microwave Magazine Date publication: 06.-2017, volume: 18, issue:4, pages: 36 - 45 Editeur: IEEE Document complet vers site de l'éditeur
» 22.2 ch Audio Encoding/Decoding Hardware System Based on MPEG-4 AAC
 Résumé:A 22.2 multichannel (22.2 ch) sound system has been adopted as an audio system for 8K Super Hi-Vision (8K). The 22.2 ch sound system is an advanced sound system composed of 24 channels three-dimensionally located in a space to envelop listeners in an immersive sound field. NHK has been working on standardizing and developing an 8K broadcasting system via a broadcasting satellite in time for test broadcasting in 2016. For an audio coding scheme, NHK developed a world-first 22.2 ch audio encoding/decoding hardware system (22.2 ch audio codec) capable of real time encoding/decoding. The fabricated 22.2 ch audio codec is based on MPEG-4 AAC and was assembled into the 8K codec together with the 8K video codec and the multiplexer. The audio quality of the fabricated 22.2 ch audio codec was assessed in an objective evaluation, and the evaluation results revealed the operational bit rates of the fabricated codec. An 8K satellite broadcasting experiment was carried out as a final verification test of the 8K broadcasting system, and 22.2 ch audio codec was found to be valid. Auteurs: Takehiro Sugimoto;Yasushige Nakayama;Tomoyasu Komori; Apparue dans: IEEE Transactions on Broadcasting Date publication: 06.-2017, volume: 63, issue:2, pages: 426 - 432 Editeur: IEEE Document complet vers site de l'éditeur
» 25-Gb/s Transmission Over 2.5-km SSMF by Silicon MRR Enhanced 1.55- $\mu \text{m}$ III-V/SOI DML
 Résumé:The use of a micro-ring resonator (MRR) to enhance the modulation extinction ratio and dispersion tolerance of a directly modulated laser is experimentally investigated with a bit rate of 25 Gb/s as proposed for the next generation data center communications. The investigated system combines a 11-GHz 1.55- $\mu \text{m}$ directly modulated hybrid III–V/SOI DFB laser realized by bonding III–V materials (InGaAlAs) on a silicon-on-insulator (SOI) wafer and a silicon MRR also fabricated on SOI. Such a transmitter enables error-free transmission ( $\text {BER}<10^{-9}$ ) at 25 Gb/s data rate over 2.5-km standard single mode fiber without dispersion compensation nor forward error correction. As both laser and MRR are fabricated on the SOI platform, they could be combined into a single device with enhanced performance, thus providing a cost-effective transmitter for short reach applications. Auteurs: Valentina Cristofori;Francesco Da Ros;Oskars Ozolins;Mohamed E. Chaibi;Laurent Bramerie;Yunhong Ding;Xiaodan Pang;Alexandre Shen;Antonin Gallet;Guang-Hua Duan;Karim Hassan;Ségolene Olivier;Sergei Popov;Gunnar Jacobsen;Leif K. Oxenløwe;C Apparue dans: IEEE Photonics Technology Letters Date publication: 06.-2017, volume: 29, issue:12, pages: 960 - 963 Editeur: IEEE Document complet vers site de l'éditeur
» 25-Gb/s Transmission Over 2.5-km SSMF by Silicon MRR Enhanced 1.55- $\mu \text{m}$ III-V/SOI DML
 Résumé:The use of a micro-ring resonator (MRR) to enhance the modulation extinction ratio and dispersion tolerance of a directly modulated laser is experimentally investigated with a bit rate of 25 Gb/s as proposed for the next generation data center communications. The investigated system combines a 11-GHz 1.55- $\mu \text{m}$ directly modulated hybrid III–V/SOI DFB laser realized by bonding III–V materials (InGaAlAs) on a silicon-on-insulator (SOI) wafer and a silicon MRR also fabricated on SOI. Such a transmitter enables error-free transmission ( $\text {BER}<10^{-9}$ ) at 25 Gb/s data rate over 2.5-km standard single mode fiber without dispersion compensation nor forward error correction. As both laser and MRR are fabricated on the SOI platform, they could be combined into a single device with enhanced performance, thus providing a cost-effective transmitter for short reach applications. Auteurs: Valentina Cristofori;Francesco Da Ros;Oskars Ozolins;Mohamed E. Chaibi;Laurent Bramerie;Yunhong Ding;Xiaodan Pang;Alexandre Shen;Antonin Gallet;Guang-Hua Duan;Karim Hassan;Ségolene Olivier;Sergei Popov;Gunnar Jacobsen;Leif K. Oxenløwe;C Apparue dans: IEEE Photonics Technology Letters Date publication: 06.-2017, volume: 29, issue:12, pages: 960 - 963 Editeur: IEEE Document complet vers site de l'éditeur
» 25-Gb/s Transmission Over 2.5-km SSMF by Silicon MRR Enhanced 1.55- $\mu \text{m}$ III-V/SOI DML
 Résumé:The use of a micro-ring resonator (MRR) to enhance the modulation extinction ratio and dispersion tolerance of a directly modulated laser is experimentally investigated with a bit rate of 25 Gb/s as proposed for the next generation data center communications. The investigated system combines a 11-GHz 1.55- $\mu \text{m}$ directly modulated hybrid III–V/SOI DFB laser realized by bonding III–V materials (InGaAlAs) on a silicon-on-insulator (SOI) wafer and a silicon MRR also fabricated on SOI. Such a transmitter enables error-free transmission ( $\text {BER}<10^{-9}$ ) at 25 Gb/s data rate over 2.5-km standard single mode fiber without dispersion compensation nor forward error correction. As both laser and MRR are fabricated on the SOI platform, they could be combined into a single device with enhanced performance, thus providing a cost-effective transmitter for short reach applications. Auteurs: Valentina Cristofori;Francesco Da Ros;Oskars Ozolins;Mohamed E. Chaibi;Laurent Bramerie;Yunhong Ding;Xiaodan Pang;Alexandre Shen;Antonin Gallet;Guang-Hua Duan;Karim Hassan;Ségolene Olivier;Sergei Popov;Gunnar Jacobsen;Leif K. Oxenløwe;C Apparue dans: IEEE Photonics Technology Letters Date publication: 06.-2017, volume: 29, issue:12, pages: 960 - 963 Editeur: IEEE Document complet vers site de l'éditeur
» 25-Gb/s Transmission Over 2.5-km SSMF by Silicon MRR Enhanced 1.55- $\mu \text{m}$ III-V/SOI DML
 Résumé:The use of a micro-ring resonator (MRR) to enhance the modulation extinction ratio and dispersion tolerance of a directly modulated laser is experimentally investigated with a bit rate of 25 Gb/s as proposed for the next generation data center communications. The investigated system combines a 11-GHz 1.55-μm directly modulated hybrid III-V/SOI DFB laser realized by bonding III-V materials (InGaAlAs) on a silicon-on-insulator (SOI) wafer and a silicon MRR also fabricated on SOI. Such a transmitter enables error-free transmission (BER <; 10-9) at 25 Gb/s data rate over 2.5-km standard single mode fiber without dispersion compensation nor forward error correction. As both laser and MRR are fabricated on the SOI platform, they could be combined into a single device with enhanced performance, thus providing a cost-effective transmitter for short reach applications. Auteurs: Valentina Cristofori;Francesco Da Ros;Oskars Ozolins;Mohamed E. Chaibi;Laurent Bramerie;Yunhong Ding;Xiaodan Pang;Alexandre Shen;Antonin Gallet;Guang-Hua Duan;Karim Hassan;Ségolene Olivier;Sergei Popov;Gunnar Jacobsen;Leif K. Oxenløwe;C Apparue dans: IEEE Photonics Technology Letters Date publication: 06.-2017, volume: 29, issue:12, pages: 960 - 963 Editeur: IEEE Document complet vers site de l'éditeur
» 2DTriPnP: A Robust Two-Dimensional Method for Fine Visual Localization Using Google Streetview Database
 Résumé:The complete camera pose (location + orientation) of the Google street view (GSV) images is provided by Google. Hence, one can utilize this information to localize a query camera based on the projective geometry. The existing literature works either perform image retrieval-based rough location recognition or require high-computational power/specific features for three-dimensional fine localization. In this paper, we propose a robust 2-D method for outdoor image-based localization using the GSV database. Having found the nearest neighboring images (best matches) in the GSV database using image retrieval techniques or the GPS circle information, the proposed method can be applied for robust fine localization of pedestrians/vehicles. The proposed method first finds the common features among the three views, i.e., query view and two from the best matches. Next, for each common feature, a 2-D triangulation is performed using the retrieved database images to find the feature world coordinates. We call this procedure “2DTri.” Afterward, a novel set of nonlinear equations is solved to estimate the fine location of the query. The novel set of equations can be interpreted as a 2-D version of the well-known perspective n-point (PnP) problem, which we call “2DPnP.” Hence, the proposed method is named “2DTriPnP.” The 2DPnP step is performed in a robust way, which is more accurate and considerably less complex compared to the conventional RANSAC-based robust methods. 2DTriPnP will be demonstrated experimentally to show better localization performance compared to other state-of-the-art methods. Auteurs: Hamed Sadeghi;Shahrokh Valaee;Shahram Shirani; Apparue dans: IEEE Transactions on Vehicular Technology Date publication: 06.-2017, volume: 66, issue:6, pages: 4678 - 4690 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D Analytical Analysis of Magnetic Field of Flux Reversal Linear-Rotary Permanent-Magnet Actuator
 Résumé:This paper develops a 3-D analytical model to compute the no-load magnetic-field distribution in a flux reversal linear-rotary permanent-magnet actuator (FR-LRPMA) with two permanent-magnet (PM) poles (PM_pole) and two ferromagnetic poles (Fe_pole) on each stator tooth. Laplace’s and Poisson’s equations are built assuming that the stator and the rotor are slotless and both the permeances of Fe_pole and PM_pole are the same. The tubular mover is transferred into a planar one using a curvature factor. Then a 2-D model and 3-D model for calculating the air-gap relative permeances are proposed considering the effect of slot and the permeance difference of Fe_pole and PM_pole, respectively. The expressions of 3-D magnetic flux density, cogging force, and cogging torque of the FR-LRPMA are subsequently derived and verified using the finite-element method. Auteurs: Kaikai Guo;Shuhua Fang;Heyun Lin;Hui Yang;Yunkai Huang;Ping Jin; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 5 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D Electric Field Computation of Steeple Rooftop Houses Near HVDC Transmission Lines
 Résumé:The existence of residential houses will distort the ion flow field under high-voltage direct current transmission lines. High efficiency electric field computational method is required during the engineering design. In this paper, the surface charge method is applied in the space-charge-free electric field computation, and a half-analytical integration strategy is presented to accelerate the computational speed. Then, ion flow field around the house is computed based on Deutsch assumption. The calculation methods are validated by the experiment in the laboratory. Electric field intensity around the top edge of steeple rooftop is larger than other areas, and the field distribution characteristics on the steeple rooftop are significantly different from flat rooftop. Auteurs: Donglai Wang;Tiebing Lu;Qinyuan Li;Bo Chen;Xuebao Li; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D IC Interconnect Parasitic Capacitance Extraction With a Reformulated PGD Algorithm
 Résumé:Proper generalized decomposition (PGD) is a recently developed model-order reduction method based on the use of variable-separated representations. In this paper, space variable-separated PGD is applied on the 3-D capacitance extraction of interconnects in integrated circuits to reduce its computational complexity. To make the PGD solver feasible, the complex boundary conditions are simplified by a characteristic function technique. 3-D singular-value decomposition of the coefficient functions is avoided by using a reformulated PGD algorithm, and therefore, the proposed method can effectively deal with problems with inhomogeneous dielectric layers and dummy fills. Numerical examples are given to verify the method. Auteurs: Yalan Li;Shuai Yan;Xiaoyu Xu;Pengfei Lyu;Zhuoxiang Ren; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D Modeling of Electromagnetic Wave Propagation in the Uniform Earth-Ionosphere Cavity Using a Commercial FDTD Software Package
 Résumé:Extremely low frequency (3–3000 Hz) electromagnetic (EM) wave propagation in the (3-D) cavity composed of the earth’s crust and uniform ionospheric lossy layers is modeled using the finite-difference time-domain algorithm set in a commercial simulation software. EM propagation and attenuation in the Earth-ionosphere waveguide are computed, and the Schumann resonance (SR) parameters are obtained from the spectra. The overall accuracy of the SR parameters surpasses 90%, despite a fairly coarse resolution of the system. We show that a commercial software can accurately and efficiently model such a large and complex geophysical system. Auteurs: Christian Kwisanga;Coenrad J. Fourie; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3275 - 3278 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D Printed Substrate Integrated Slab Waveguide for Single-Mode Bandwidth Enhancement
 Résumé:This letter presents the implementation of a broadband substrate integrated waveguide (SIW) by an additive manufacturing technique. A 3-D printed material based on Ninjaflex filament has been realized by fused deposition modeling. By changing the infill percentage, printed materials with different dielectric properties have been fabricated and experimentally characterized. Two materials obtained from the same filament with different infill percentages have been used for the implementation of a substrate integrated slab waveguide (SISW), which allows increasing the single-mode bandwidth compared with that of a standard SIW. The experimental results for the fundamental and second modes of SIW and SISW show a 50% bandwidth enhancement. Auteurs: Enrico Massoni;Lorenzo Silvestri;Gianluca Alaimo;Stefania Marconi;Maurizio Bozzi;Luca Perregrini;Ferdinando Auricchio; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 06.-2017, volume: 27, issue:6, pages: 536 - 538 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D Sub-Domain Analytical Model to Calculate Magnetic Flux Density in Induction Machines With Semiclosed Slots Under No-Load Condition
 Résumé:In this paper, a novel 3-D sub-domain analytical model is developed to determine magnetic flux distribution in single-cage induction machines (IMs) with skewed rotor bars under no-load condition in an effort to more detailed analysis of spatial harmonics. The proposed model, along with an optimization algorithm, is as an alternative solution to finite-element analysis (FEA) in optimizing the geometry of IMs. The analytical method is based on the resolution of 3-D Laplace and Poisson’s equations in cylindrical coordinates using the separation of variables method to calculate the magnetic vector potential for corresponding sub-domain. The proposed model includes the effect of slotting and tooth tips for the stator and rotor slots, which is usually neglected in a 2-D analysis due to the complexity of differential equations. Also, the proposed 3-D model can be used for any slot-pole combination in addition to considering the asymmetrical effect in the axial direction, which is a source of noise, vibration, and excessive losses in IMs. To evaluate the performance of the proposed 3-D analytical model, calculated magnetic-field distribution is compared with the results obtained from the 3-D FEA. Auteurs: Aida Mollaeian;Eshaan Ghosh;Himavarsha Dhulipati;Jimi Tjong;Narayan C. Kar; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 5 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D-MIMO With Massive Antennas Paves the Way to 5G Enhanced Mobile Broadband: From System Design to Field Trials
 Résumé:Three-dimensional (3D) multiple input and multiple output (3D-MIMO) with massive antennas is a key technology to achieve high spectral efficiency and user experienced data rate for the fifth generation (5G) mobile communication system. To implement 3D-MIMO in 5G system, practical constraints on the product design should be considered. This paper proposes a systematic design for the 3D-MIMO product by considering the restrictions of both base band and the hardware, including cost, size, weight, and heat dissipation. The design has been implemented for 2.6-GHz time-division duplex band, and field trials have been conducted for performance validation with practical intercell interference in commercial network. The trial results show that this 3D-MIMO design can meet the spectral efficiency requirement of the 5G enhanced mobile broadband services. The performance gain of 3D-MIMO varies with the traffic load. When the traffic load is heavy, 3D-MIMO can enhance the cell throughput by 4~6.7 times. When the traffic load is low, the performance gain of this 3D-MIMO design decreases. The results from field trial also show that the performance of 3D-MIMO degrades in mobility scenarios, where further enhancement on acquiring instant channel status information are necessary to improve the robustness of 3D-MIMO to mobility. Auteurs: Guangyi Liu;Xueying Hou;Jing Jin;Fei Wang;Qixing Wang;Yue Hao;Yuhong Huang;Xiaoyun Wang;Xiao Xiao;Ailin Deng; Apparue dans: IEEE Journal on Selected Areas in Communications Date publication: 06.-2017, volume: 35, issue:6, pages: 1222 - 1233 Editeur: IEEE Document complet vers site de l'éditeur
» 35-GHz Wideband Circularly Polarized Patch Array on LTCC
 Résumé:A 35-GHz wideband circularly polarized (CP) patch array of $2\times 2$ elements using low-temperature cofired ceramic technology is presented. The widened 3-dB axial ratio (AR) bandwidth is achieved by constructing a $1 \times 2$ sequentially rotated CP patch array with small inner-element spacing in the antenna element. The antenna element consists of two close circular patches with diagonal perturbations, and the patches are rotated with respect to each other. The two patches are fed with equal amplitude and orthogonal phase difference using one probe, which has one vertical part and two different horizontal parts. The fabricated array with a dimension of $15.3 \times 28.3\times 1.3$ mm3 shows wide −10-dB $\mid S_{11} \mid$ and 3-dB AR bandwidths of over 29.6% and 26%, respectively. The measured maximum gain of the four-element array is 9.3 dBi with slight fluctuations over 31–39 GHz frequency range. Auteurs: Ming Du;Yuliang Dong;Jun Xu;Xiao Ding; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3235 - 3240 Editeur: IEEE Document complet vers site de l'éditeur
» 48-Mode Reconfigurable Design of SDF FFT Hardware Architecture Using Radix-32 and Radix-23 Design Approaches
 Résumé:In this paper, we propose a reconfigurable (RC) fast Fourier transform (FFT) design in a systematic design scheme. The RC design bricks are mainly proposed to arbitrarily concatenate to support FFT-point required. Meanwhile, we show three developed design techniques, including six-type RC processing element, systematic first-in first-out reuse arrangement, and section-based twiddle factor generator to elaborate our FFT design. In a design/implementation example, it can support up to 2187 FFT-point manipulation and 48 RC modes. It also supports 32 operating modes defined in 3GPP-LTE standard. In application-specified integrated circuit implementation with TSMC 90-nm CMOS technology, our design work occupies a core area of 1.664 mm2 and consumes 35.2 mW under maximal clock frequency of 188.67 MHz. This paper also has outstanding design performance in terms of speed-area ratio and power-frequency ratio for comparison reference. Auteurs: Xin-Yu Shih;Yue-Qu Liu;Hong-Ru Chou; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 06.-2017, volume: 64, issue:6, pages: 1456 - 1467 Editeur: IEEE Document complet vers site de l'éditeur
» 5G Developments Are in Full Swing [Mobile Radio]
 Résumé:Nokia has successfully carried out the world's first connection based on the Verizon fifth-generation (V5G) technical forum (TF) interface, which is known as the industry-agreed specification for prestandard 5G applications. The test adds another key component to the development of 5G technologies and the execution of the first 5G applications, demonstrating the ability to provide fast-paced implementation, according to early standards, including device interoperability. At the end of 2016, Nokia introduced 4.5G Pro and announced plans for 4.9G, providing operators with the critical increases to capacity and speed that will be needed for future 5G operations. Auteurs: Matthias Pätzold; Apparue dans: IEEE Vehicular Technology Magazine Date publication: 06.-2017, volume: 12, issue:2, pages: 4 - 12 Editeur: IEEE Document complet vers site de l'éditeur
» 5G Field Trials: OFDM-Based Waveforms and Mixed Numerologies
 Résumé:Service diversity is expected in the upcoming fifth-generation (5G) cellular networks, which poses great challenges to the underlying waveforms to accommodate heterogeneous service requirements in a flexible way. By dividing the bandwidth into several subbands, each having a different numerology, this paper reports a field trial in time division duplex downlink conducted on a configurable test bed in a real-world environment for the performance evaluations of orthogonal frequency-division multiplexing (OFDM)-based 5G waveform candidates, i.e., cyclically prefixed OFDM (CP-OFDM), windowing OFDM (W-OFDM), and filtered OFDM (f-OFDM), in the presence of mixed numerologies. Field trial results confirm the feasibility of mixed numerologies and reveal the impact of several important system parameters, e.g., guard bandwidth, data bandwidth, signal-to-noise ratio (SNR), and transmit power. The results also suggest that f-OFDM outperforms CP-OFDM and W-OFDM in terms of both the spectrum efficiency and robustness in a high SNR regime, and the gain increases with a higher inter-numerology out-of-band interference. In some specific scenarios, ideal spectrum utilization can be realized by f-OFDM which completely removes the guard band. Auteurs: Peng Guan;Dan Wu;Tingjian Tian;Jianwei Zhou;Xi Zhang;Liang Gu;Anass Benjebbour;Masashi Iwabuchi;Yoshihisa Kishiyama; Apparue dans: IEEE Journal on Selected Areas in Communications Date publication: 06.-2017, volume: 35, issue:6, pages: 1234 - 1243 Editeur: IEEE Document complet vers site de l'éditeur
» 5G-Enabled Cooperative Intelligent Vehicular (5GenCIV) Framework: When Benz Meets Marconi
 Résumé:As one of the most popular social media platforms today, Twitter provides people with an effective way to communicate and interact with each other. Through these interactions, influence among users gradually emerges and changes people's opinions. Although previous work has studied interpersonal influence as the probability of activating others during information diffusion, they ignore an important fact that information diffusion is the result of influence, while dynamic interactions among users produce influence. In this article, the authors propose a novel temporal influence model to learn users' opinion behaviors regarding a specific topic by exploring how influence emerges during communications. The experiments show that their model performs better than other influence models with different influence assumptions when predicting users' future opinions, especially for the users with high opinion diversity. Auteurs: Xiang Cheng;Chen Chen;Wuxiong Zhang;Yang Yang; Apparue dans: IEEE Intelligent Systems Date publication: 06.-2017, volume: 32, issue:3, pages: 53 - 59 Editeur: IEEE Document complet vers site de l'éditeur
» 5G: A Tutorial Overview of Standards, Trials, Challenges, Deployment, and Practice
 Résumé:There is considerable pressure to define the key requirements of 5G, develop 5G standards, and perform technology trials as quickly as possible. Normally, these activities are best done in series but there is a desire to complete these tasks in parallel so that commercial deployments of 5G can begin by 2020. 5G will not be an incremental improvement over its predecessors; it aims to be a revolutionary leap forward in terms of data rates, latency, massive connectivity, network reliability, and energy efficiency. These capabilities are targeted at realizing high-speed connectivity, the Internet of Things, augmented virtual reality, the tactile internet, and so on. The requirements of 5G are expected to be met by new spectrum in the microwave bands (3.3–4.2 GHz), and utilizing large bandwidths available in mm-wave bands, increasing spatial degrees of freedom via large antenna arrays and 3-D MIMO, network densification, and new waveforms that provide scalability and flexibility to meet the varying demands of 5G services. Unlike the one size fits all 4G core networks, the 5G core network must be flexible and adaptable and is expected to simultaneously provide optimized support for the diverse 5G use case categories. In this paper, we provide an overview of 5G research, standardization trials, and deployment challenges. Due to the enormous scope of 5G systems, it is necessary to provide some direction in a tutorial article, and in this overview, the focus is largely user centric, rather than device centric. In addition to surveying the state of play in the area, we identify leading technologies, evaluating their strengths and weaknesses, and outline the key challenges ahead, with research test beds delivering promising performance but pre-commercial trials lagging behind the desired 5G targets. Auteurs: Mansoor Shafi;Andreas F. Molisch;Peter J. Smith;Thomas Haustein;Peiying Zhu;Prasan De Silva;Fredrik Tufvesson;Anass Benjebbour;Gerhard Wunder; Apparue dans: IEEE Journal on Selected Areas in Communications Date publication: 06.-2017, volume: 35, issue:6, pages: 1201 - 1221 Editeur: IEEE Document complet vers site de l'éditeur
» 6-DoF Haptic Rendering Using Continuous Collision Detection between Points and Signed Distance Fields
 Résumé:We present an algorithm for fast continuous collision detection between points and signed distance fields, and demonstrate how to robustly use it for 6-DoF haptic rendering of contact between objects with complex geometry. Continuous collision detection is often needed in computer animation, haptics, and virtual reality applications, but has so far only been investigated for polygon (triangular) geometry representations. We demonstrate how to robustly and continuously detect intersections between points and level sets of the signed distance field. We suggest using an octree subdivision of the distance field for fast traversal of distance field cells. We also give a method to resolve continuous collisions between point clouds organized into a tree hierarchy and a signed distance field, enabling rendering of contact between rigid objects with complex geometry. We investigate and compare two 6-DoF haptic rendering methods now applicable to point-versus-distance field contact for the first time: continuous integration of penalty forces, and a constraint-based method. An experimental comparison to discrete collision detection demonstrates that the continuous method is more robust and can correctly resolve collisions even under high velocities and during complex contact. Auteurs: Hongyi Xu;Jernej Barbič; Apparue dans: IEEE Transactions on Haptics Date publication: 06.-2017, volume: 10, issue:2, pages: 151 - 161 Editeur: IEEE Document complet vers site de l'éditeur
» 94-GHz CMOS Power Amplifiers Using Miniature Dual Y-Shaped Combiner With RL Load
 Résumé:This paper reports two four-way 94-GHz power amplifiers (PAs) for radar sensors in 90-nm CMOS technology. The first PA (PA1) comprises a two-stage common-source (CS) cascaded input stage with wideband $\pi$ -match input, interstage and output networks, followed by a two-way CS gain stage using Y-shaped divider and combiner, and a four-way CS output stage using dual Y-shaped divider and combiner. At each branch’s input terminal (i.e., drain terminal of the parallel CS output stage), the low-loss dual Y-shaped combiners can convert the serial RL load into the impedance for optimal output power ( ${P} _{\mathrm { {out}}}$ ) and power-added efficiency (PAE). To enhance power gain and PAE performance, the second PA (PA2) adopts a two-stage positive-feedback CS cascaded input stage using $\lambda$ /2 transmission line. The circuit architecture of the gain and output stages is the same as that of PA1. PA1 achieves power gain of 16, 21, and 12 dB, respectively, at 60, 77, and 94 GHz. In addition, PA1 achieves ${P}_{\mathrm { {out}}}$ of 13.2, 12, and 10.6 dBm, respectively, at 60, 77, and 94 GHz. The corresponding peak PAE is 20%, 16%, and 10.2%, respectively, at 60, 77, and 94 GHz. At 94 GHz, PA2 achieves power gain of 20 dB, ${P}_{\mathrm { {out}}}$ of 16.8 dBm, and peak PAE of 16.4%. The overall performance of the two CMOS PAs is remarkable in ${V}$ -band and ${W}$ -band. Auteurs: Yo-Sheng Lin;Van Kien Nguyen; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 06.-2017, volume: 64, issue:6, pages: 1285 - 1298 Editeur: IEEE Document complet vers site de l'éditeur
» In Situ Waveform Measurements Within Doherty Power Amplifier Under Operational Conditions
 Résumé:In this contribution, a gallium nitride-based 1 GHz Doherty amplifier with in situ waveform measurement capability is presented. With this measurement approach, the high frequency time-domain voltages and currents can be measured directly within the circuit. Therefore, directional couplers are integrated into the output matching network of the carrier and the peak amplifier. In contrast to other measurement techniques for investigating amplifiers under laboratory conditions, with this approach, a more in-depth investigation of realized power amplifiers can be carried out under operational conditions, e.g., for tuning. Especially, it is possible to characterize the interaction of the carrier and the peak amplifier. Hence, to the best knowledge of the authors the load modulation of a Doherty amplifier at the fundamental and the higher harmonics is measured for the first time. Auteurs: Steffen Probst;Eckhard Denicke;Bernd Geck; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 06.-2017, volume: 65, issue:6, pages: 2192 - 2200 Editeur: IEEE Document complet vers site de l'éditeur
» In Vitro Multi-Functional Microelectrode Array Featuring 59 760 Electrodes, 2048 Electrophysiology Channels, Stimulation, Impedance Measurement, and Neurotransmitter Detection Channels
 Résumé:Biological cells are characterized by highly complex phenomena and processes that are, to a great extent, interdependent. To gain detailed insights, devices designed to study cellular phenomena need to enable tracking and manipulation of multiple cell parameters in parallel; they have to provide high signal quality and high-spatiotemporal resolution. To this end, we have developed a CMOS-based microelectrode array system for in vitro applications that integrates six measurement and stimulation functions, the largest number to date. Moreover, the system features the largest active electrode array area to date ( $4.48 \times 2.43$ mm2) to accommodate 59 760 electrodes, while its power consumption, noise characteristics, and spatial resolution (13.5- $\mu$ m electrode pitch) are comparable to the best state-of-the-art devices. The system includes: 2048 action potential (AP, bandwidth: 300 Hz–10 kHz) recording units, 32 local-field-potential (LFP, bandwidth: 1 Hz–300 Hz) recording units, 32 current recording units, 32 impedance measurement units, and 28 neurotransmitter detection units, in addition to the 16 dual-mode voltage-only or current/voltage-controlled stimulation units. The electrode array architecture is based on a switch matrix, which allows for connecting any measurement/stimulation unit to any electrode in the array and for performing different measurement/stimulation functions in parallel. Auteurs: Jelena Dragas;Vijay Viswam;Amir Shadmani;Yihui Chen;Raziyeh Bounik;Alexander Stettler;Milos Radivojevic;Sydney Geissler;Marie Engelene J. Obien;Jan Müller;Andreas Hierlemann; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1576 - 1590 Editeur: IEEE Document complet vers site de l'éditeur
» crowddeliver: Planning City-Wide Package Delivery Paths Leveraging the Crowd of Taxis
 Résumé:Despite the great demand on and attempts at package express shipping services, online retailers have not yet had a practical solution to make such services profitable. In this paper, we propose an economical approach to express package delivery, i.e., exploiting relays of taxis with passengers to help transport package collectively, without degrading the quality of passenger services. Specifically, we propose a two-phase framework called crowddeliver for the package delivery path planning. In the first phase, we mine the historical taxi trajectory data offline to identify the shortest package delivery paths with estimated travel time given any Origin–Destination pairs. Using the paths and travel time as the reference, in the second phase we develop an online adaptive taxi scheduling algorithm to find the near-optimal delivery paths iteratively upon real-time requests and direct the package routing accordingly. Finally, we evaluate the two-phase framework using the real-world data sets, which consist of a point of interest, a road network, and the large-scale trajectory data, respectively, that are generated by 7614 taxis in a month in the city of Hangzhou, China. Results show that over 85% of packages can be delivered within 8 hours, with around 4.2 relays of taxis on average. Auteurs: Chao Chen;Daqing Zhang;Xiaojuan Ma;Bin Guo;Leye Wang;Yasha Wang;Edwin Sha; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 06.-2017, volume: 18, issue:6, pages: 1478 - 1496 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.015-mm$^{\text{2}}$ Inductorless 32-GHz Clock Generator With Wide Frequency-Tuning Range in 28-nm CMOS Technology
 Résumé:This brief illustrates the design of an inductorless high-speed clock generator. Compared to inductance-capacitance ($LC$) oscillators, ring oscillators are used in order to achieve a wide frequency-tuning range with a small chip area. By employing a cascaded phase-locked loop (PLL) architecture, the phase noise of the oscillator can be effectively suppressed. The first PLL is implemented with high-voltage devices under 1.8-V supply to provide a clean reference for the second PLL. The second PLL consists of only low-voltage devices, with a supply voltage of 0.9 V for high-speed operation. Following the second PLL, a clock doubler multiplies the PLL output clock by a factor of 2, which avoids power-consuming high-frequency clock dividers. In order to minimize any mismatch effects, special layout techniques are employed for the second voltage-controlled oscillator and the clock doubler. The prototype chip was fabricated in 28-nm complementary metal oxide semiconductor (CMOS) technology, and it occupies an active area of only 0.015 mm2. The proposed PLL achieves a maximum output frequency of 32 GHz and consumes a total power of 30 mW, exhibiting a power efficiency of 0.9 mW/GHz. Auteurs: Gyu-Seob Jeong;Wooseok Kim;Jaejin Park;Taeik Kim;Hojin Park;Deog-Kyoon Jeong; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 06.-2017, volume: 64, issue:6, pages: 655 - 659 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.015-mm$^{\text{2}}$ Inductorless 32-GHz Clock Generator With Wide Frequency-Tuning Range in 28-nm CMOS Technology
 Résumé:This brief illustrates the design of an inductorless high-speed clock generator. Compared to inductance-capacitance ($LC$) oscillators, ring oscillators are used in order to achieve a wide frequency-tuning range with a small chip area. By employing a cascaded phase-locked loop (PLL) architecture, the phase noise of the oscillator can be effectively suppressed. The first PLL is implemented with high-voltage devices under 1.8-V supply to provide a clean reference for the second PLL. The second PLL consists of only low-voltage devices, with a supply voltage of 0.9 V for high-speed operation. Following the second PLL, a clock doubler multiplies the PLL output clock by a factor of 2, which avoids power-consuming high-frequency clock dividers. In order to minimize any mismatch effects, special layout techniques are employed for the second voltage-controlled oscillator and the clock doubler. The prototype chip was fabricated in 28-nm complementary metal oxide semiconductor (CMOS) technology, and it occupies an active area of only 0.015 mm2. The proposed PLL achieves a maximum output frequency of 32 GHz and consumes a total power of 30 mW, exhibiting a power efficiency of 0.9 mW/GHz. Auteurs: Gyu-Seob Jeong;Wooseok Kim;Jaejin Park;Taeik Kim;Hojin Park;Deog-Kyoon Jeong; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 06.-2017, volume: 64, issue:6, pages: 655 - 659 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.015-mm$^{\text{2}}$ Inductorless 32-GHz Clock Generator With Wide Frequency-Tuning Range in 28-nm CMOS Technology
 Résumé:This brief illustrates the design of an inductorless high-speed clock generator. Compared to inductance-capacitance ($LC$) oscillators, ring oscillators are used in order to achieve a wide frequency-tuning range with a small chip area. By employing a cascaded phase-locked loop (PLL) architecture, the phase noise of the oscillator can be effectively suppressed. The first PLL is implemented with high-voltage devices under 1.8-V supply to provide a clean reference for the second PLL. The second PLL consists of only low-voltage devices, with a supply voltage of 0.9 V for high-speed operation. Following the second PLL, a clock doubler multiplies the PLL output clock by a factor of 2, which avoids power-consuming high-frequency clock dividers. In order to minimize any mismatch effects, special layout techniques are employed for the second voltage-controlled oscillator and the clock doubler. The prototype chip was fabricated in 28-nm complementary metal oxide semiconductor (CMOS) technology, and it occupies an active area of only 0.015 mm2. The proposed PLL achieves a maximum output frequency of 32 GHz and consumes a total power of 30 mW, exhibiting a power efficiency of 0.9 mW/GHz. Auteurs: Gyu-Seob Jeong;Wooseok Kim;Jaejin Park;Taeik Kim;Hojin Park;Deog-Kyoon Jeong; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 06.-2017, volume: 64, issue:6, pages: 655 - 659 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.015-mm$^{\text{2}}$ Inductorless 32-GHz Clock Generator With Wide Frequency-Tuning Range in 28-nm CMOS Technology
 Résumé:This brief illustrates the design of an inductorless high-speed clock generator. Compared to inductance-capacitance ($LC$) oscillators, ring oscillators are used in order to achieve a wide frequency-tuning range with a small chip area. By employing a cascaded phase-locked loop (PLL) architecture, the phase noise of the oscillator can be effectively suppressed. The first PLL is implemented with high-voltage devices under 1.8-V supply to provide a clean reference for the second PLL. The second PLL consists of only low-voltage devices, with a supply voltage of 0.9 V for high-speed operation. Following the second PLL, a clock doubler multiplies the PLL output clock by a factor of 2, which avoids power-consuming high-frequency clock dividers. In order to minimize any mismatch effects, special layout techniques are employed for the second voltage-controlled oscillator and the clock doubler. The prototype chip was fabricated in 28-nm complementary metal oxide semiconductor (CMOS) technology, and it occupies an active area of only 0.015 mm2. The proposed PLL achieves a maximum output frequency of 32 GHz and consumes a total power of 30 mW, exhibiting a power efficiency of 0.9 mW/GHz. Auteurs: Gyu-Seob Jeong;Wooseok Kim;Jaejin Park;Taeik Kim;Hojin Park;Deog-Kyoon Jeong; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 06.-2017, volume: 64, issue:6, pages: 655 - 659 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.015-mm$^{\text{2}}$ Inductorless 32-GHz Clock Generator With Wide Frequency-Tuning Range in 28-nm CMOS Technology
 Résumé:This brief illustrates the design of an inductorless high-speed clock generator. Compared to inductance-capacitance (LC) oscillators, ring oscillators are used in order to achieve a wide frequency-tuning range with a small chip area. By employing a cascaded phase-locked loop (PLL) architecture, the phase noise of the oscillator can be effectively suppressed. The first PLL is implemented with high-voltage devices under 1.8-V supply to provide a clean reference for the second PLL. The second PLL consists of only low-voltage devices, with a supply voltage of 0.9 V for high-speed operation. Following the second PLL, a clock doubler multiplies the PLL output clock by a factor of 2, which avoids power-consuming high-frequency clock dividers. In order to minimize any mismatch effects, special layout techniques are employed for the second voltage-controlled oscillator and the clock doubler. The prototype chip was fabricated in 28-nm complementary metal oxide semiconductor (CMOS) technology, and it occupies an active area of only 0.015 mm2. The proposed PLL achieves a maximum output frequency of 32 GHz and consumes a total power of 30 mW, exhibiting a power efficiency of 0.9 mW/GHz. Auteurs: Gyu-Seob Jeong;Wooseok Kim;Jaejin Park;Taeik Kim;Hojin Park;Deog-Kyoon Jeong; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 06.-2017, volume: 64, issue:6, pages: 655 - 659 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.035-pJ/bit/dB 20-Gb/s Adaptive Linear Equalizer With an Adaptation Time of 2.68 $\mu\text{s}$
 Résumé:A 20-Gb/s adaptive linear equalizer with a coefficient fast-converging method is presented. By using the asynchronous sampling technique, the power dissipation of the circuits, realizing the adaptation method, can be reduced. However, the equalization coefficients require a considerable amount of time to be determined. To shorten the asynchronous sampling time, the high-frequency gain of the linear equalizer is calibrated prior to the low-frequency one. With a 20-Gb/s pseudorandom binary sequence of $2^{7}-1$, the measured bit-error-rates are all less than 10−12 for channel loss from −7.98 to −18.3 dB. Moreover, the equalization coefficients are determined within 2.68 $\mu\text{s}$. Fabricated in a 40-nm CMOS technology, this equalizer totally consumes 12.8 mW from a 1.1-V supply, of which only 4.9 mW dissipates in the circuits, realizing the proposed method. The calculated figure-of-merit is 0.035-pJ/bit/dB. Auteurs: Kuan-Yu Chen;Wei-Yung Chen;Shen-Iuan Liu; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 06.-2017, volume: 64, issue:6, pages: 645 - 649 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.42-mW 1-Mb/s 3- to 4-GHz Transceiver in 0.18- $\mu \text{m}$ CMOS With Flexible Efficiency, Bandwidth, and Distance Control for IoT Applications
 Résumé:This paper describes a short-range transceiver architecture using frequency-hopped sinusoidal OOK pulses. Since signal bandwidth does not necessarily have to satisfy >500 MHz requirement like conventional ultra-wideband (UWB) pulses, the proposed transceiver named as a very-wide band (VWB) transceiver offers degrees of freedom to choose an optimum operation duty cycle in terms of energy efficiency, bandwidth efficiency, and communication range, while providing much lower operation duty cycle than that of narrow band OOK transceiver. The VWB transmission significantly relaxes the complexity of transceiver design without requiring advanced CMOS technology. In the transmitter, pulse generation circuit design is simplified with the duty-cycled sinusoidal signal compared to that in the impulse-radio UWB (IR-UWB) transmitter. In the receiver, an asynchronous energy detection topology is proposed to achieve robust energy detection by overcoming the synchronization issue as well as the saturation problem of the integrator circuit. A prototype 3-to-4 GHz VWB transceiver is implemented in 0.18 $\mu \text{m}$ CMOS. The transceiver achieves the communication distance of >2 m at 1 Mb/s data rate with the peak-to-peak pulse amplitude of only 300 mV and the duty cycle of 0.6%, consuming 0.42 mW from a 1.8 V supply. Auteurs: Dang Liu;Xuwen Ni;Ranran Zhou;Woogeun Rhee;Zhihua Wang; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1479 - 1494 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.42-mW 1-Mb/s 3- to 4-GHz Transceiver in 0.18- $\mu \text{m}$ CMOS With Flexible Efficiency, Bandwidth, and Distance Control for IoT Applications
 Résumé:This paper describes a short-range transceiver architecture using frequency-hopped sinusoidal OOK pulses. Since signal bandwidth does not necessarily have to satisfy >500 MHz requirement like conventional ultra-wideband (UWB) pulses, the proposed transceiver named as a very-wide band (VWB) transceiver offers degrees of freedom to choose an optimum operation duty cycle in terms of energy efficiency, bandwidth efficiency, and communication range, while providing much lower operation duty cycle than that of narrow band OOK transceiver. The VWB transmission significantly relaxes the complexity of transceiver design without requiring advanced CMOS technology. In the transmitter, pulse generation circuit design is simplified with the duty-cycled sinusoidal signal compared to that in the impulse-radio UWB (IR-UWB) transmitter. In the receiver, an asynchronous energy detection topology is proposed to achieve robust energy detection by overcoming the synchronization issue as well as the saturation problem of the integrator circuit. A prototype 3-to-4 GHz VWB transceiver is implemented in 0.18 $\mu \text{m}$ CMOS. The transceiver achieves the communication distance of >2 m at 1 Mb/s data rate with the peak-to-peak pulse amplitude of only 300 mV and the duty cycle of 0.6%, consuming 0.42 mW from a 1.8 V supply. Auteurs: Dang Liu;Xuwen Ni;Ranran Zhou;Woogeun Rhee;Zhihua Wang; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1479 - 1494 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.42-mW 1-Mb/s 3- to 4-GHz Transceiver in 0.18- $\mu \text{m}$ CMOS With Flexible Efficiency, Bandwidth, and Distance Control for IoT Applications
 Résumé:This paper describes a short-range transceiver architecture using frequency-hopped sinusoidal OOK pulses. Since signal bandwidth does not necessarily have to satisfy >500 MHz requirement like conventional ultra-wideband (UWB) pulses, the proposed transceiver named as a very-wide band (VWB) transceiver offers degrees of freedom to choose an optimum operation duty cycle in terms of energy efficiency, bandwidth efficiency, and communication range, while providing much lower operation duty cycle than that of narrow band OOK transceiver. The VWB transmission significantly relaxes the complexity of transceiver design without requiring advanced CMOS technology. In the transmitter, pulse generation circuit design is simplified with the duty-cycled sinusoidal signal compared to that in the impulse-radio UWB (IR-UWB) transmitter. In the receiver, an asynchronous energy detection topology is proposed to achieve robust energy detection by overcoming the synchronization issue as well as the saturation problem of the integrator circuit. A prototype 3-to-4 GHz VWB transceiver is implemented in 0.18 $\mu \text{m}$ CMOS. The transceiver achieves the communication distance of >2 m at 1 Mb/s data rate with the peak-to-peak pulse amplitude of only 300 mV and the duty cycle of 0.6%, consuming 0.42 mW from a 1.8 V supply. Auteurs: Dang Liu;Xuwen Ni;Ranran Zhou;Woogeun Rhee;Zhihua Wang; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1479 - 1494 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.42-mW 1-Mb/s 3- to 4-GHz Transceiver in 0.18- $\mu \text{m}$ CMOS With Flexible Efficiency, Bandwidth, and Distance Control for IoT Applications
 Résumé:This paper describes a short-range transceiver architecture using frequency-hopped sinusoidal OOK pulses. Since signal bandwidth does not necessarily have to satisfy >500 MHz requirement like conventional ultra-wideband (UWB) pulses, the proposed transceiver named as a very-wide band (VWB) transceiver offers degrees of freedom to choose an optimum operation duty cycle in terms of energy efficiency, bandwidth efficiency, and communication range, while providing much lower operation duty cycle than that of narrow band OOK transceiver. The VWB transmission significantly relaxes the complexity of transceiver design without requiring advanced CMOS technology. In the transmitter, pulse generation circuit design is simplified with the duty-cycled sinusoidal signal compared to that in the impulse-radio UWB (IR-UWB) transmitter. In the receiver, an asynchronous energy detection topology is proposed to achieve robust energy detection by overcoming the synchronization issue as well as the saturation problem of the integrator circuit. A prototype 3-to-4 GHz VWB transceiver is implemented in 0.18 μm CMOS. The transceiver achieves the communication distance of >2 m at 1 Mb/s data rate with the peak-to-peak pulse amplitude of only 300 mV and the duty cycle of 0.6%, consuming 0.42 mW from a 1.8 V supply. Auteurs: Dang Liu;Xuwen Ni;Ranran Zhou;Woogeun Rhee;Zhihua Wang; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1479 - 1494 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.42-mW 1-Mb/s 3- to 4-GHz Transceiver in 0.18- $\mu \text{m}$ CMOS With Flexible Efficiency, Bandwidth, and Distance Control for IoT Applications
 Résumé:This paper describes a short-range transceiver architecture using frequency-hopped sinusoidal OOK pulses. Since signal bandwidth does not necessarily have to satisfy >500 MHz requirement like conventional ultra-wideband (UWB) pulses, the proposed transceiver named as a very-wide band (VWB) transceiver offers degrees of freedom to choose an optimum operation duty cycle in terms of energy efficiency, bandwidth efficiency, and communication range, while providing much lower operation duty cycle than that of narrow band OOK transceiver. The VWB transmission significantly relaxes the complexity of transceiver design without requiring advanced CMOS technology. In the transmitter, pulse generation circuit design is simplified with the duty-cycled sinusoidal signal compared to that in the impulse-radio UWB (IR-UWB) transmitter. In the receiver, an asynchronous energy detection topology is proposed to achieve robust energy detection by overcoming the synchronization issue as well as the saturation problem of the integrator circuit. A prototype 3-to-4 GHz VWB transceiver is implemented in 0.18 μm CMOS. The transceiver achieves the communication distance of >2 m at 1 Mb/s data rate with the peak-to-peak pulse amplitude of only 300 mV and the duty cycle of 0.6%, consuming 0.42 mW from a 1.8 V supply. Auteurs: Dang Liu;Xuwen Ni;Ranran Zhou;Woogeun Rhee;Zhihua Wang; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1479 - 1494 Editeur: IEEE Document complet vers site de l'éditeur
» A 1.2-GS/s 8-bit Two-Step SAR ADC in 65-nm CMOS With Passive Residue Transfer
 Résumé:A high-speed 2b–1b/cycle two-step successive-approximation-register analog-to-digital converter (ADC) exploiting the passive residue transfer technique is reported. The removal of the residue amplifier results in savings in the time and power consumed by the residue transfer process. The kT/C noise and potential bandwidth mismatch associated with the passive residue transfer are analyzed and also verified by circuit simulations. The use of the 2b–1b/cycle hybrid conversion scheme with an appropriate resolution partition further enhances the conversion speed. Fabricated in a 65-nm CMOS process, the prototype ADC measured a signal-to-noise plus distortion ratio of 43.7 dB and a spurious-free dynamic range of 58.1 dB for a near-Nyquist input. The total power consumption of the ADC is 5 mW and the achieved figure of merit is 35 fJ/conversion-step, all measured at a sample rate of 1.2 GS/s. Auteurs: Hai Huang;Ling Du;Yun Chiu; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1551 - 1562 Editeur: IEEE Document complet vers site de l'éditeur
» A 1.9-mm-Precision 20-GHz Direct-Sampling Receiver Using Time-Extension Method for Indoor Localization
 Résumé:This paper presents an impulse-radio ultra-wideband (IR-UWB) receiver design for precise wireless ranging using a newly proposed direct sampling with time-extension (DTE) method. To overcome the problems encountered in high-speed sampling for impulse signals, the DTE method, which exploits the characteristics of an impulse, is proposed. The proposed method performs high-speed sampling only during the period when short pulses exist, and quantizes the sampled signal during the dead time where no pulses exist. The high-speed impulse signal can be easily digitized using low-speed analog-to-digital converter. We designed and fabricated the IR-UWB receiver using a 65-nm CMOS process. The measurement result shows a 1.9-mm resolution for indoor wireless ranging within a 1-m range. The receiver has a power consumption of 70 mW at 1.2 V and energy efficiency of 1554 nJ/pulse. Auteurs: Hong Gul Han;Byung Gyu Yu;Tae Wook Kim; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1509 - 1520 Editeur: IEEE Document complet vers site de l'éditeur
» A 100 MHz PRF IR-UWB CMOS Transceiver With Pulse Shaping Capabilities and Peak Voltage Detector
 Résumé:This paper presents a high-rate IR-UWB transceiver chipset implemented in a 130-nm CMOS technology for WBAN and biomedical applications in the 3.1–4.9 GHz band. The transmitter is based on a pulse synthesizer and an analytical up-converted Gaussian pulse is used to predict its settings. Its measured peak-to-peak output voltage is equal to $0.9~V_{\mathrm{ pp}}$ on a 100 $\Omega$ load for a central frequency of 4 GHz, and a supply voltage of 1.2 V, which gives an emitted energy per pulse of 0.64 pJ. The receiver is a non-coherent architecture based on an LNA followed by a peak-voltage detector. A BER of 10−3 is measured for a 3.1–4.9 GHz input peak-to-peak pulse amplitude of 1.1 mV, which corresponds to a sensitivity of −85.8 dBm at 1 Mb/s and gives a communication range estimated to 1.9 m. Auteurs: Remy Vauche;Eloi Muhr;Olivier Fourquin;Sylvain Bourdel;Jean Gaubert;Nicolas Dehaese;Stephane Meillere;Herve Barthelemy;Laurent Ouvry; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 06.-2017, volume: 64, issue:6, pages: 1612 - 1625 Editeur: IEEE Document complet vers site de l'éditeur
» A 10T-4MTJ Nonvolatile Ternary CAM Cell for Reliable Search Operation and a Compact Area
 Résumé:Ternary content addressable memory (TCAM) is widely used in high-speed searching applications. Recently, zero standby power has been in high demand for battery-powered devices such as mobile phones, Internet of Things, and wearable devices. Thus, several nonvolatile TCAM (NV-TCAM) cells have been researched to realize zero standby power. However, they suffer from low reliability in search operation. We propose a 10T-4MTJ NV-TCAM cell that significantly improves the reliability of search operation utilizing the differential sensing and positive feedback of cross-coupled PMOSs. The advantages of the proposed cell are verified by HSPICE Monte Carlo simulations using industry-compatible 45-nm model parameters. With a cell area of 2.78 $\mu\text{m}^{2}$ (1.12 times smaller than a SRAM-based TCAM cell) and a search delay of 1 ns, the proposed cell satisfies a target search pass yield of $6\sigma$ (98.24% yield for an 18-Mb TCAM macro), whereas the previous cells achieved only 3.3 and $3.6\sigma$. Auteurs: Byungkyu Song;Taehui Na;Jung Pill Kim;Seung H. Kang;Seong-Ook Jung; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 06.-2017, volume: 64, issue:6, pages: 700 - 704 Editeur: IEEE Document complet vers site de l'éditeur
» A 1600-Element Dual-Frequency Electronically Reconfigurable Reflectarray at X/Ku-Band
 Résumé:A dual-frequency reconfigurable reflectarray (RRA) is proposed and verified experimentally. The RRA consists of 1600 electronically controllable elements. By integrating only a single PIN diode, the proposed element is capable to operate at two working frequencies with 1-bit phase resolution. The dual-frequency mechanism is explained through the mode analysis, and a parametric study is performed to provide guidelines for determining the two working frequencies. As an example, a 1600-element RRA prototype is realized by assembling five identical $8 \times 40$ subarrays. An field programmable gate array control board is used to achieve real-time phase control of each element individually. The experimental results show that the broadside gains of the RRA are 29.3 and 30.8 dBi at 11.1 and 14.3 GHz, respectively. Excellent beam scanning performance is also obtained at both frequencies. Auteurs: Huanhuan Yang;Fan Yang;Xiangyu Cao;Shenheng Xu;Jun Gao;Xibi Chen;Maokun Li;Tong Li; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3024 - 3032 Editeur: IEEE Document complet vers site de l'éditeur
» A 172 $\mu$W Compressively Sampled Photoplethysmographic (PPG) Readout ASIC With Heart Rate Estimation Directly From Compressively Sampled Data
 Résumé:A compressive sampling (CS) photoplethysmographic (PPG) readout with embedded feature extraction to estimate heart rate (HR) directly from compressively sampled data is presented. It integrates a low-power analog front end together with a digital back end to perform feature extraction to estimate the average HR over a 4 s interval directly from compressively sampled PPG data. The application-specified integrated circuit (ASIC) supports uniform sampling mode (1x compression) as well as CS modes with compression ratios of 8x, 10x, and 30x. CS is performed through nonuniformly subsampling the PPG signal, while feature extraction is performed using least square spectral fitting through Lomb–Scargle periodogram. The ASIC consumes 172 $\mu$ W of power from a 1.2 V supply while reducing the relative LED driver power consumption by up to 30 times without significant loss of relevant information for accurate HR estimation. Auteurs: Venkata Rajesh Pamula;Jose Manuel Valero-Sarmiento;Long Yan;Alper Bozkurt;Chris Van Hoof;Nick Van Helleputte;Refet Firat Yazicioglu;Marian Verhelst; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 487 - 496 Editeur: IEEE Document complet vers site de l'éditeur
» A 172 $\mu$W Compressively Sampled Photoplethysmographic (PPG) Readout ASIC With Heart Rate Estimation Directly From Compressively Sampled Data
 Résumé:A compressive sampling (CS) photoplethysmographic (PPG) readout with embedded feature extraction to estimate heart rate (HR) directly from compressively sampled data is presented. It integrates a low-power analog front end together with a digital back end to perform feature extraction to estimate the average HR over a 4 s interval directly from compressively sampled PPG data. The application-specified integrated circuit (ASIC) supports uniform sampling mode (1x compression) as well as CS modes with compression ratios of 8x, 10x, and 30x. CS is performed through nonuniformly subsampling the PPG signal, while feature extraction is performed using least square spectral fitting through Lomb–Scargle periodogram. The ASIC consumes 172 $\mu$ W of power from a 1.2 V supply while reducing the relative LED driver power consumption by up to 30 times without significant loss of relevant information for accurate HR estimation. Auteurs: Venkata Rajesh Pamula;Jose Manuel Valero-Sarmiento;Long Yan;Alper Bozkurt;Chris Van Hoof;Nick Van Helleputte;Refet Firat Yazicioglu;Marian Verhelst; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 487 - 496 Editeur: IEEE Document complet vers site de l'éditeur
» A 172 $\mu$W Compressively Sampled Photoplethysmographic (PPG) Readout ASIC With Heart Rate Estimation Directly From Compressively Sampled Data
 Résumé:A compressive sampling (CS) photoplethysmographic (PPG) readout with embedded feature extraction to estimate heart rate (HR) directly from compressively sampled data is presented. It integrates a low-power analog front end together with a digital back end to perform feature extraction to estimate the average HR over a 4 s interval directly from compressively sampled PPG data. The application-specified integrated circuit (ASIC) supports uniform sampling mode (1x compression) as well as CS modes with compression ratios of 8x, 10x, and 30x. CS is performed through nonuniformly subsampling the PPG signal, while feature extraction is performed using least square spectral fitting through Lomb–Scargle periodogram. The ASIC consumes 172 $\mu$ W of power from a 1.2 V supply while reducing the relative LED driver power consumption by up to 30 times without significant loss of relevant information for accurate HR estimation. Auteurs: Venkata Rajesh Pamula;Jose Manuel Valero-Sarmiento;Long Yan;Alper Bozkurt;Chris Van Hoof;Nick Van Helleputte;Refet Firat Yazicioglu;Marian Verhelst; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 487 - 496 Editeur: IEEE Document complet vers site de l'éditeur
» A 172 $\mu$W Compressively Sampled Photoplethysmographic (PPG) Readout ASIC With Heart Rate Estimation Directly From Compressively Sampled Data
 Résumé:A compressive sampling (CS) photoplethysmographic (PPG) readout with embedded feature extraction to estimate heart rate (HR) directly from compressively sampled data is presented. It integrates a low-power analog front end together with a digital back end to perform feature extraction to estimate the average HR over a 4 s interval directly from compressively sampled PPG data. The application-specified integrated circuit (ASIC) supports uniform sampling mode (1× compression) as well as CS modes with compression ratios of 8×, 10×, and 30×. CS is performed through nonuniformly subsampling the PPG signal, while feature extraction is performed using least square spectral fitting through Lomb-Scargle periodogram. The ASIC consumes 172 μW of power from a 1.2 V supply while reducing the relative LED driver power consumption by up to 30 times without significant loss of relevant information for accurate HR estimation. Auteurs: Venkata Rajesh Pamula;Jose Manuel Valero-Sarmiento;Long Yan;Alper Bozkurt;Chris Van Hoof;Nick Van Helleputte;Refet Firat Yazicioglu;Marian Verhelst; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 487 - 496 Editeur: IEEE Document complet vers site de l'éditeur
» A 172 $\mu$W Compressively Sampled Photoplethysmographic (PPG) Readout ASIC With Heart Rate Estimation Directly From Compressively Sampled Data
 Résumé:A compressive sampling (CS) photoplethysmographic (PPG) readout with embedded feature extraction to estimate heart rate (HR) directly from compressively sampled data is presented. It integrates a low-power analog front end together with a digital back end to perform feature extraction to estimate the average HR over a 4 s interval directly from compressively sampled PPG data. The application-specified integrated circuit (ASIC) supports uniform sampling mode (1× compression) as well as CS modes with compression ratios of 8×, 10×, and 30×. CS is performed through nonuniformly subsampling the PPG signal, while feature extraction is performed using least square spectral fitting through Lomb-Scargle periodogram. The ASIC consumes 172 μW of power from a 1.2 V supply while reducing the relative LED driver power consumption by up to 30 times without significant loss of relevant information for accurate HR estimation. Auteurs: Venkata Rajesh Pamula;Jose Manuel Valero-Sarmiento;Long Yan;Alper Bozkurt;Chris Van Hoof;Nick Van Helleputte;Refet Firat Yazicioglu;Marian Verhelst; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 487 - 496 Editeur: IEEE Document complet vers site de l'éditeur
» A 2.24-mW, 61.8-dB SNDR, 20-MS/s Pipelined ADC With Charge-Pump-Based Dynamic Biasing for Power Reduction in Op Amp Sharing
 Résumé:A high-speed dynamic biasing technique is presented for reducing op amp power in discrete-time, multistage, analog circuits employing op amp sharing. To exploit typical power scaling in such circuits, a charge pump, of which the on-times of up and down currents are controlled by two comparators, performs rapid change of the op amp bias condition between a low-current mode and a high-current mode during nonoverlapping clock periods of the two phase clocks. The errors caused by finite comparator delay are compensated for by embedding intentional offset voltages in the comparators, which are implemented by using asymmetric differential input pairs in the comparators. To verify the efficacy of the proposed biasing technique, an 11-b pipelined analog-to-digital converter (ADC) has been implemented using 0.15- $\mu \text{m}$ devices in a 28-nm CMOS technology. With a 20-MHz sampling clock, the ADC achieves a 61.8-dB SNDR while consuming a 2.24-mW power from a 1.8-V supply. The MDAC and ADC power are reduced by about 45% and 30%, respectively, compared with a conventional pipelined ADC employing an op amp in each MDAC. Owing to the simple structure of the proposed dynamic biasing, the prototype ADC occupies only 0.052 mm2. Auteurs: Je-Kwang Cho; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 06.-2017, volume: 64, issue:6, pages: 1368 - 1379 Editeur: IEEE Document complet vers site de l'éditeur
» A 2.4-GHz ZigBee Transmitter Using a Function-Reuse Class-F DCO-PA and an ADPLL Achieving 22.6% (14.5%) System Efficiency at 6-dBm (0-dBm) $P_{\mathrm {out}}$
 Résumé:This paper describes a sub-1-V 2.4-GHz ZigBee transmitter (TX) with scalable output power ( $P_{\mathrm {out}}$ ) and system efficiency. It features a function-reuse class-F topology unifying the digital-controlled oscillator (DCO) and power amplifier (PA), designated as DCO-PA. Unlike the existing current-reuse topologies that rely on transistor stacking, here the power consumption of the DCO and PA-driver is absorbed into the DCO-PA without losing the voltage headroom, while allowing a low supply voltage. The DCO-PA also benefits from a six-port transformer with customized coupling coefficients and turn ratios to jointly perform the functions of resonant tank and output matching network, saving the chip area. A fractional-N all-digital phase-locked loop (ADPLL) realizes a two-point data modulation. Its phase-interpolated time-to-digital converter prevents time-consuming calibration. The entire TX fabricated in 65-nm CMOS occupies a 0.39-mm $^{\mathrm { {2}}}$ active area. The standalone DCO-PA shows a peak efficiency of 26.2% at a 6-dBm $P_{\mathrm {out}}$ , and a back-off efficiency of 17.7% at a −4.3 dBm $P_{\mathrm {out}}$ under a scalable supply voltage (0.3–0.7 V). The system efficiency, including the ADPLL, is 22.6% (14.5%) at 6-dBm (0-dBm) $P_{\mathrm {out}}$ . The HS-OQPSK modulated output complies with the ZigBee spectral mask with an adequate margin and the error vector magnitude is 2.29%. Auteurs: Xingqiang Peng;Jun Yin;Pui-In Mak;Wei-Han Yu;Rui P. Martins; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1495 - 1508 Editeur: IEEE Document complet vers site de l'éditeur
» A 23-mW Face Recognition Processor with Mostly-Read 5T Memory in 40-nm CMOS
 Résumé:This paper presents an energy-efficient face detection and recognition processor aimed at mobile applications. The algorithmic optimizations including hybrid search scheme for face detection significantly reduce computational complexity and architecture modification such as feature memory segmentation and further reduce energy consumption. We utilize characteristics of the implemented algorithm and propose a 5T SRAM design heavily optimized for mostly-read operations. Systematic reset and write schemes allow for reliable data write operation. The 5T SRAM reduces the cell area by 7.2% compared to a conventional 6T bit cell in logic rule while significantly improving read margin and voltage scalability due to a decoupled read path. The fabricated processor consumes only 23 mW while processing both face detection and recognition in real time at 5.5 frames/s throughput. Auteurs: Dongsuk Jeon;Qing Dong;Yejoong Kim;Xiaolong Wang;Shuai Chen;Hao Yu;David Blaauw;Dennis Sylvester; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1628 - 1642 Editeur: IEEE Document complet vers site de l'éditeur
» A 250-Mb/s to 6-Gb/s Referenceless Clock and Data Recovery Circuit With Clock Frequency Multiplier
 Résumé:This brief describes the design and implementation of a 250-Mb/s to 6-Gb/s single-loop referenceless clock and data recovery circuit. The clock frequency multiplier and the referenceless frequency acquisition circuit are used to cover a wide-range data rate. The clock frequency multiplier is proposed to generate the 6-GHz clock with low jitter. In addition, the voltage-controlled oscillator operates at 1/5-rate frequency of the sampling clock, which has a merit of low power consumption. The proposed circuit achieves 9.56-ps rms jitter, consumes 13.2 mW at 6 Gb/s, and occupies 0.0944 mm2 in a 65-nm CMOS technology. Auteurs: Ja-Young Kim;Junyoung Song;Jungtaek You;Sewook Hwang;Sang-Geun Bae;Chulwoo Kim; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 06.-2017, volume: 64, issue:6, pages: 650 - 654 Editeur: IEEE Document complet vers site de l'éditeur
» A 28-GHz SiGe BiCMOS PA With 32% Efficiency and 23-dBm Output Power
 Résumé:In this paper, we present a two-stage, four-way combined power amplifier (PA) operating in the 27–31-GHz frequency range in 180-nm SiGe BiCMOS technology. The output network of the PA employs spiral transformers and a microstrip T-combiner to realize low-loss two-way series, two-way parallel power combining. With the help of a lumped-element transformer model, we present a co-optimization technique for the transformer and the adjoining matching components to minimize the power loss of the full output network. The design methodology is applicable for realizing an arbitrary impedance at the device plane with a K-way series, M-way parallel combiner. The efficacy of this technique is demonstrated by the realization of a PA, which has 27.6-dB gain, 23.2-dBm, 1-dB compressed output power, 32.7% power-added efficiency (PAE) at 1-dB compression, and 15% PAE at 6-dB back off. Linearity measurements show less than 4° amplitude-modulation to phase-modulation distortion below 3-dB back off and less than −32-dBc intermodulation product at 6-dB back off. Auteurs: Anirban Sarkar;Farshid Aryanfar;Brian A. Floyd; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1680 - 1686 Editeur: IEEE Document complet vers site de l'éditeur
» A 3-D Hybrid Cell Method for Induction Heating Problems
 Résumé:A novel hybrid approach for solving induction heating problems is presented. The electrothermal problem is discretized by the cell method (CM) and coupled to the boundary element method to avoid the air region meshing. The interface coupling is obtained by introducing a new topological framework for the CM, which is the augmented dual grid. The main advantage is that the electromagnetic hybrid formulation for computing time-harmonic eddy currents results in a partly dense indefinite linear system, which is solved by a fast TFQMR iterative method. The transient thermal problem, weakly coupled to the electrical one, is solved by the $\theta$ method under convection and radiation boundary conditions. The hybrid approach shows to be very accurate by comparison with third-order 2-D FEM on an axisymmetric test case. The applicability of the method then extends to full 3-D models with limited computing resources. Auteurs: F. Moro;L. Codecasa; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» A 3-D Topographic-Relief-Correlated Monte Carlo Radiative Transfer Simulator for Forest Bidirectional Reflectance Estimation
 Résumé:Understanding the physical processes that affect electromagnetic waves within forests is a key to better analysis of global environmental change. In this letter, we propose a 3-D vector model called the topographic-relief-correlated Monte Carlo (MC) radiative transfer simulator for estimating the bidirectional reflectance factor (BRF) of a forest with complex terrain relief. Unlike existing models, this model takes into account rugged terrain conditions by modeling the ground surface as a bilinear surface interpolated from a digital elevation model. The proposed model is compared with the well-performing MC model FLiES for validation, and good agreement is obtained. Forest BRF estimations for six different terrain relief conditions are derived, and these BRFs have reasonable variation according to ground conditions. Auteurs: Sheng-Ye Jin;Junichi Susaki; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 06.-2017, volume: 14, issue:6, pages: 964 - 968 Editeur: IEEE Document complet vers site de l'éditeur
» A 30-W 90% Efficiency Dual-Mode Controlled DC–DC Controller With Power Over Ethernet Interface for Power Device
 Résumé:A dual-mode controlled dc–dc controller with power over Ethernet (PoE) interface for power device (PD) is presented that is designed to support drawing power either from an Ethernet cable or from an external auxiliary supply support (ASS). PoE interface supports all the functions that comply with the IEEE802.3af/at standard. Based on bandgap reference structure, a detection comparator is provided to detect input voltage without extra voltage reference. Using a low offset voltage amplifier, a low-loss current-limiting technique is proposed to achieve a high-precision current-limit point. Based on a high-speed comparator and two timing capacitors, an oscillator (OSC) is implemented for better accuracy, and provides the maximum duty cycle ( $D_{\mathrm {max}}$ ) and external frequency synchronization. The chip is fabricated in a 0.5- $\mu \text{m}$ 65 V BCD process and occupies a die size (with pads) of $1.79 \times 2.76$ mm2. The experimental results are measured for an active clamp forward converter with a wide range of dc input voltages from 33 to 57 V, an output voltage of 12 V, and an output power of 30 W. The chip achieves peak power efficiency of 90% and 90.63% on DC and ASS, respectively. The load regulation at different input voltages can be measured to be within ±0.11%. Measurements further show that the peak-to-peak ripple voltage of the chip is 161 mV and the recovery time is less than 1.2 ms for the 2-A load step. Auteurs: Yongyuan Li;Zhangming Zhu; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 06.-2017, volume: 25, issue:6, pages: 1943 - 1953 Editeur: IEEE Document complet vers site de l'éditeur
» A 34-pJ/bit Area-Efficient ASK Demodulator Based on Switching-Mode Signal Shaping
 Résumé:This brief presents a new amplitude shift-keying (ASK) demodulator for biomedical implants based on waveform shaping on detected envelope signals. The proposed demodulator incorporates a novel switching-mode signal shaper, which can operate with much lower power consumption. The design does not require any comparator or Schmitt trigger and operates with a very low number of elements; thus, the silicon area is highly saved. With a carrier frequency of 5 MHz and a data rate of 500 kb/s, the proposed ASK demodulator can extract data with modulation indexes down to 5%, whereas the bit-error rate can be as low as 10−5 depending on the input signal-to-noise ratio. Using a 0.18-$\mu\text{m}$ CMOS process, the demodulator occupies a die size of 920 $\mu\text{m}^{2}$. The average power consumption of the proposed demodulator is only 17 $\mu\text{W}$ by physical measurement on silicon. Auteurs: Mehdi Lotfi Navaii;Mohsen Jalali;Hamed Sadjedi; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 06.-2017, volume: 64, issue:6, pages: 640 - 644 Editeur: IEEE Document complet vers site de l'éditeur
» A 3T1R Nonvolatile TCAM Using MLC ReRAM for Frequent-Off Instant-On Filters in IoT and Big-Data Processing
 Résumé:Existing nonvolatile ternary content-addressable-memory (nvTCAM) suffers from limited word-length (WDL), large write-energy ( $E_{W})$ and search-energy ( $E_{S})$ , and large cell area (A). This paper develops a 3T1R nvTCAM cell using a single multiple-level cell (MLC)-resistive RAM (ReRAM) device to achieve long WDL, lower $E_{W}$ and $E_{S}$ , and reduced cell area. Two peripheral control schemes were developed, dual-replica-row self-timed and invalid-entry power consumption suppression (IEPCS), for the suppression of dc current in 3T1R nvTCAM cells in order to reduce $E_{S}$ . Two versions of the IEPCS scheme were developed (basic and charge-recycle-controlled) to alter the tradeoff between area overhead and power consumption in the updating of invalid-bits. A $128~\text {b} \times 64$ b 3T1R nvTCAM macro was fabricated using back-end-of-line ReRAM under 90-nm CMOS process. The fabricated MLC-based 3T1R nvTCAM macro achieved sub-1-ns search-delay and sub-6-ns wake-up time with supply voltage of 1 V and WDL = 64 b. Auteurs: Meng-Fan Chang;Chien-Chen Lin;Albert Lee;Yen-Ning Chiang;Chia-Chen Kuo;Geng-Hau Yang;Hsiang-Jen Tsai;Tien-Fu Chen;Shyh-Shyuan Sheu; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1664 - 1679 Editeur: IEEE Document complet vers site de l'éditeur
» A 400 MHz Wireless Neural Signal Processing IC With 625 $\times$ On-Chip Data Reduction and Reconfigurable BFSK/QPSK Transmitter Based on Sequential Injection Locking
 Résumé:An 8-channel wireless neural signal processing IC, which can perform real-time spike detection, alignment, and feature extraction, and wireless data transmission is proposed. A reconfigurable BFSK/QPSK transmitter (TX) at MICS/MedRadio band is incorporated to support different data rate requirement. By using an Exponential Component-Polynomial Component (EC-PC) spike processing unit with an incremental principal component analysis (IPCA) engine, the detection of neural spikes with poor SNR is possible while achieving $625\times$ data reduction. For the TX, a dual-channel at 401 MHz and 403.8 MHz are supported by applying sequential injection locked techniques while attaining phase noise of ${-}$102 dBc/Hz at 100 kHz offset. From the measurement, error vector magnitude (EVM) of 4.60%/9.55% with power amplifier (PA) output power of ${-}$15 dBm is achieved for the QPSK at 8 Mbps and the BFSK at 12.5 kbps. Fabricated in 65 nm CMOS with an active area of 1 mm $^2$, the design consumes a total current of 5 $\sim$5.6 mA with a maximum energy efficiency of 0.7 nJ/b. Auteurs: Kok-Hin Teng;Tong Wu;Xiayun Liu;Zhi Yang;Chun-Huat Heng; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 547 - 557 Editeur: IEEE Document complet vers site de l'éditeur
» A 400 MHz Wireless Neural Signal Processing IC With 625 $\times$ On-Chip Data Reduction and Reconfigurable BFSK/QPSK Transmitter Based on Sequential Injection Locking
 Résumé:An 8-channel wireless neural signal processing IC, which can perform real-time spike detection, alignment, and feature extraction, and wireless data transmission is proposed. A reconfigurable BFSK/QPSK transmitter (TX) at MICS/MedRadio band is incorporated to support different data rate requirement. By using an Exponential Component-Polynomial Component (EC-PC) spike processing unit with an incremental principal component analysis (IPCA) engine, the detection of neural spikes with poor SNR is possible while achieving $625\times$ data reduction. For the TX, a dual-channel at 401 MHz and 403.8 MHz are supported by applying sequential injection locked techniques while attaining phase noise of ${-}$102 dBc/Hz at 100 kHz offset. From the measurement, error vector magnitude (EVM) of 4.60%/9.55% with power amplifier (PA) output power of ${-}$15 dBm is achieved for the QPSK at 8 Mbps and the BFSK at 12.5 kbps. Fabricated in 65 nm CMOS with an active area of 1 mm $^2$, the design consumes a total current of 5 $\sim$5.6 mA with a maximum energy efficiency of 0.7 nJ/b. Auteurs: Kok-Hin Teng;Tong Wu;Xiayun Liu;Zhi Yang;Chun-Huat Heng; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 547 - 557 Editeur: IEEE Document complet vers site de l'éditeur
» A 400 MHz Wireless Neural Signal Processing IC With 625 $\times$ On-Chip Data Reduction and Reconfigurable BFSK/QPSK Transmitter Based on Sequential Injection Locking
 Résumé:An 8-channel wireless neural signal processing IC, which can perform real-time spike detection, alignment, and feature extraction, and wireless data transmission is proposed. A reconfigurable BFSK/QPSK transmitter (TX) at MICS/MedRadio band is incorporated to support different data rate requirement. By using an Exponential Component-Polynomial Component (EC-PC) spike processing unit with an incremental principal component analysis (IPCA) engine, the detection of neural spikes with poor SNR is possible while achieving $625\times$ data reduction. For the TX, a dual-channel at 401 MHz and 403.8 MHz are supported by applying sequential injection locked techniques while attaining phase noise of ${-}$102 dBc/Hz at 100 kHz offset. From the measurement, error vector magnitude (EVM) of 4.60%/9.55% with power amplifier (PA) output power of ${-}$15 dBm is achieved for the QPSK at 8 Mbps and the BFSK at 12.5 kbps. Fabricated in 65 nm CMOS with an active area of 1 mm $^2$, the design consumes a total current of 5 $\sim$5.6 mA with a maximum energy efficiency of 0.7 nJ/b. Auteurs: Kok-Hin Teng;Tong Wu;Xiayun Liu;Zhi Yang;Chun-Huat Heng; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 547 - 557 Editeur: IEEE Document complet vers site de l'éditeur
» A 400 MHz Wireless Neural Signal Processing IC With 625 $\times$ On-Chip Data Reduction and Reconfigurable BFSK/QPSK Transmitter Based on Sequential Injection Locking
 Résumé:An 8-channel wireless neural signal processing IC, which can perform real-time spike detection, alignment, and feature extraction, and wireless data transmission is proposed. A reconfigurable BFSK/QPSK transmitter (TX) at MICS/MedRadio band is incorporated to support different data rate requirement. By using an Exponential Component-Polynomial Component (ECPC) spike processing unit with an incremental principal component analysis (IPCA) engine, the detection of neural spikes with poor SNR is possible while achieving 625× data reduction. For the TX, a dual-channel at 401 MHz and 403.8 MHz are supported by applying sequential injection locked techniques while attaining phase noise of -102 dBc/Hz at 100 kHz offset. From the measurement, error vector magnitude (EVM) of 4.60%/9.55% with power amplifier (PA) output power of -15 dBm is achieved for the QPSK at 8 Mbps and the BFSK at 12.5 kbps. Fabricated in 65 nm CMOS with an active area of 1 mm2, the design consumes a total current of 5~5.6 mA with a maximum energy efficiency of 0.7 nJ/b. Auteurs: Kok-Hin Teng;Tong Wu;Xiayun Liu;Zhi Yang;Chun-Huat Heng; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 547 - 557 Editeur: IEEE Document complet vers site de l'éditeur
» A 400 MHz Wireless Neural Signal Processing IC With 625 $\times$ On-Chip Data Reduction and Reconfigurable BFSK/QPSK Transmitter Based on Sequential Injection Locking
 Résumé:An 8-channel wireless neural signal processing IC, which can perform real-time spike detection, alignment, and feature extraction, and wireless data transmission is proposed. A reconfigurable BFSK/QPSK transmitter (TX) at MICS/MedRadio band is incorporated to support different data rate requirement. By using an Exponential Component-Polynomial Component (ECPC) spike processing unit with an incremental principal component analysis (IPCA) engine, the detection of neural spikes with poor SNR is possible while achieving 625× data reduction. For the TX, a dual-channel at 401 MHz and 403.8 MHz are supported by applying sequential injection locked techniques while attaining phase noise of -102 dBc/Hz at 100 kHz offset. From the measurement, error vector magnitude (EVM) of 4.60%/9.55% with power amplifier (PA) output power of -15 dBm is achieved for the QPSK at 8 Mbps and the BFSK at 12.5 kbps. Fabricated in 65 nm CMOS with an active area of 1 mm2, the design consumes a total current of 5~5.6 mA with a maximum energy efficiency of 0.7 nJ/b. Auteurs: Kok-Hin Teng;Tong Wu;Xiayun Liu;Zhi Yang;Chun-Huat Heng; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 547 - 557 Editeur: IEEE Document complet vers site de l'éditeur
» A 5.8-Gb/s Adaptive Integrating Duobinary DFE Receiver for Multi-Drop Memory Interface
 Résumé:This paper describes a 5.8 Gb/s adaptive integrating duobinary decision-feedback equalizer (DFE) for use in next-generation multi-drop memory interface. The proposed receiver combines traditional interface techniques like the integrated signaling and the duobinary signaling, in which the duobinary signal is generated by current integration in the receiver. It can address issues such as input data dependence during integration, need for precursor equalization, high equalizer gain boosting, and sensitivity to high-frequency noise. The proposed receiver also alleviates DFE critical timing to provide gain in speed, and embed DFE taps in duobinary decoding to provide gain in power and area. The adaptation for adjusting the equalizer common-mode level, duobinary zero level, tap coefficient values, and timing recovery is incorporated. The proposed DFE receiver was fabricated in a 45 nm CMOS process, whose measurement results indicated that it worked at 5.8 Gb/s speed in a four-drop channel configuration with seven slave ICs, and the bathtub curve shows 36% open for $10^{-10}$ bit error rate. Auteurs: Hyun-Wook Lim;Sung-Won Choi;Jeong-Keun Ahn;Woong-Ki Min;Sang-Kyu Lee;Chang-Hoon Baek;Jae-Youl Lee;Gyoo-Cheol Hwang;Young-Hyun Jun;Bai-Sun Kong; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1563 - 1575 Editeur: IEEE Document complet vers site de l'éditeur
» A 6-b, 800-MS/s, 3.62-mW Nyquist Rate AC-Coupled VCO-Based ADC in 65-nm CMOS
 Résumé:A Nyquist voltage-controlled oscillator (VCO)-based analog-to-digital converter (ADC) architecture is proposed for ac-coupled systems that are commonly used in high-speed wireline and wireless communications. The proposed ADC utilizes a built-in high-pass filter as an analog differentiator, replacing the digital differentiator in conventional oversampling VCO-based ADCs. As a result, it avoids quantization noise shaping and achieves wideband Nyquist operation, inherited first-order antialiasing filtering, and improved VCO linearity without calibration. Analyses and simulations of various circuit nonidealities’ effects on the proposed ADC architecture are also provided. The ADC prototype achieves a peak SNDR of 34 dB and an SFDR of 50 dB with over 400-MHz input bandwidth and a sampling rate of 800 MS/s. It occupies an active area of 0.01 mm2 and consumes 3.62 mW in 65-nm CMOS. Auteurs: Mohsen Hassanpourghadi;Praveen Kumar Sharma;Mike Shuo-Wei Chen; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 06.-2017, volume: 64, issue:6, pages: 1354 - 1367 Editeur: IEEE Document complet vers site de l'éditeur
» A Barrier Controlled Charge Plasma-Based TFET With Gate Engineering for Ambipolar Suppression and RF/Linearity Performance Improvement
 Résumé:To address the fabrication complexity and cost of nanoscale devices, a dual material control gate charge-plasma-based tunnel FET (DMCG-CPTFET) is presented for the first time for the suppression of ambipolarity and improvement of analog/radio frequency (RF), and linearity performance. The formation of p+ source and n+ drain regions in DMCG-CPTFET is done by the deposition of platinum (work- ${\mathrm{ function}} = 5.93$ eV) and hafnium (work- ${\mathrm{ function}} = 3.9$ eV) materials, respectively, over the silicon body. Hence, the proposed device avoids doping control issues, random dopant fluctuations, and it neither needs abrupt doping nor high thermal budget, which makes fabrication process simpler. In DMCG-CPTFET, the gate is divided into three segments, namely, tunneling gate (M1), control gate (M2), and auxiliary gate (M3) with their equivalent work functions as $\phi _{1}$ , $\phi _{2}$ , and $\phi _{3}$ , respectively. However, we have explored three different combinations of work-functions to achieve better performance in terms of DC, analog/RF, and linearity metrics. In various possibilities of devices, ATLAS device simulations show that the DMCG-CPTFET attains optimum result with $\phi _{1} = \phi _{3} < \phi _{2}$ , where $\phi _{1}$ is used at source side to improve the ON-state current, whereas $- phi _{3}$ (same as $\phi _{1}$ ) is considered at drain side in order to suppress the ambipolarity. Auteurs: Kaushal Nigam;Sunil Pandey;Pravin N. Kondekar;Dheeraj Sharma;Pawan Kumar Parte; Apparue dans: IEEE Transactions on Electron Devices Date publication: 06.-2017, volume: 64, issue:6, pages: 2751 - 2757 Editeur: IEEE Document complet vers site de l'éditeur
» A Behavioral Handwriting Model for Static and Dynamic Signature Synthesis
 Résumé:The synthetic generation of static handwritten signatures based on motor equivalence theory has been recently proposed for biometric applications. Motor equivalence divides the human handwriting action into an effector dependent cognitive level and an effector independent motor level. The first level has been suggested by others as an engram, generated through a spatial grid, and the second has been emulated with kinematic filters. Our paper proposes a development of this methodology in which we generate dynamic information and provide a unified comprehensive synthesizer for both static and dynamic signature synthesis. The dynamics are calculated by lognormal sampling of the 8-connected continuous signature trajectory, which includes, as a novelty, the pen-ups. The forgery generation imitates a signature by extracting the most perceptually relevant points of the given genuine signature and interpolating them. The capacity to synthesize both static and dynamic signatures using a unique model is evaluated according to its ability to adapt to the static and dynamic signature inter- and intra-personal variability. Our highly promising results suggest the possibility of using the synthesizer in different areas beyond the generation of unlimited databases for biometric training. Auteurs: Miguel A. Ferrer;Moises Diaz;Cristina Carmona-Duarte;Aythami Morales; Apparue dans: IEEE Transactions on Pattern Analysis and Machine Intelligence Date publication: 06.-2017, volume: 39, issue:6, pages: 1041 - 1053 Editeur: IEEE Document complet vers site de l'éditeur
» A Bottom-Up/Top-Down Hybrid Algorithm for Model-Based Building Detection in Single Very High Resolution SAR Image
 Résumé:Building detection from high-resolution synthetic aperture radar (SAR) image is an essential issue for many SAR applications in urban areas. In this letter, we propose a novel bottom-up/top-down hybrid algorithm for model-based building detection from single very high resolution (VHR) SAR image. First, the building model is generated and described by a set of extraction criteria, which restrict the spatial layout of a building and its primitive features. Specifically, the rectangles of different intensity levels are extracted from the SAR image as primitive features. Then the bottom-up stage proposes building candidates composed by extracted rectangles, and the top-down step predicts building candidates composed by weak features omitted in the primitive extraction. After that, all candidates are verified through false alarm detection. Under this framework, the detection performances can be greatly improved especially in dense built-up areas. The effectiveness of the proposed method is verified by experimental results obtained from real VHR SAR images. Auteurs: Bo Liu;Kan Tang;Jian Liang; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 06.-2017, volume: 14, issue:6, pages: 926 - 930 Editeur: IEEE Document complet vers site de l'éditeur
» A Breakthrough in Tumor Localization: Combining Tactile Sensing and Ultrasound to Improve Tumor Localization in Robotics-Assisted Minimally Invasive Surgery
 Résumé:Robotics-assisted minimally invasive surgery (RAMIS) helps surgeons to avoid manually palpating organs to locate subsurface tumors. One solution has been to use ultrasound, but it is not always reliable. Tactile sensing, however, has the potential to augment ultrasound to improve tumor localization, but there are no existing RAMIS instruments that employ both modalities. Auteurs: Anish S. Naidu;Michael D. Naish;Rajni V. Patel; Apparue dans: IEEE Robotics & Automation Magazine Date publication: 06.-2017, volume: 24, issue:2, pages: 54 - 62 Editeur: IEEE Document complet vers site de l'éditeur
» A Broadband Differentially Fed Dual-Polarized Planar Antenna
 Résumé:A novel broadband differentially fed dual-polarized planar antenna is proposed in this communication. The antenna is composed of two dual-dipole elements, each of which is differentially fed by two coaxial cables through a short stub. Four pairs of parasitic elements are introduced to enhance the bandwidth. Both the dual-dipole elements and the parasitic elements are etched on the same substrate, making the antenna feature a planar configuration. The antenna achieves a 15-dB differential impedance bandwidth of 45% ( $\vert S_{\mathrm{ dd11}}\vert < -15$ dB), a high isolation of 45 dB, an antenna gain of ~9 dBi, and a half-power beamwidth of 65° ± 8°. Auteurs: Yuehui Cui;Xiaona Gao;RongLin Li; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3231 - 3234 Editeur: IEEE Document complet vers site de l'éditeur
» A Broadband ML-FMA for 3-D Periodic Green’s Function in 2-D Lattice Using Ewald Summation
 Résumé:A periodic fast multipole algorithm (P-FMA) is devised for evaluating 3-D periodic Green’s function (PGF) for a 2-D lattice which can be used to solve scattering by a structure with 2-D periodicity. The introduction of periodicity in the Green’s function formulation produces image sources at each lattice site. Like multilevel FMA (ML-FMA), P-FMA takes advantage of the distance between image sources and observation points to factorize the field using multipoles. By substituting known factorizations of the free-space Green’s function into the expression for PGF, one can isolate the summation over the lattice into the translation phase of the FMA. For both plane wave and multipole factorizations, a common term known as lattice constant appears. The lattice constant is an infinite sum over the lattice which does not converge absolutely when expressed as a spatial sum. Using the Ewald summation technique, the lattice constants can be evaluated with exponential convergence and high accuracy. The resulting P-FMA is between $\mathcal {O}(N)$ and $\mathcal {O}(N\log N)$ in memory use and computational complexity, depending on the object size relative to the wavelength. Auteurs: Michael Wei;Weng C. Chew; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3134 - 3145 Editeur: IEEE Document complet vers site de l'éditeur
» A Calibration Setup for IEC 61850-9-2 Devices
 Résumé:The working principle and the architecture of a calibration system for devices operating with the IEC 61850-9-2 standard are described. Two different types of devices are considered: stand-alone merging units (SAMUs) used to retrofit conventional transformers in power network substations and commercial test sets suited for nonconventional voltage and current sensor calibration in the field. An SAMU is essentially an analog-to-digital converter delivering its results in the IEC 61850-9-2 format. The functionalities of the test set evaluated here are the analog signal generation (voltage and current) and their synchronous IEC 61850-9-2 representation. This paper presents a calibration setup that has been applied to both types of devices. Auteurs: Marco Agustoni;Alessandro Mortara; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 06.-2017, volume: 66, issue:6, pages: 1124 - 1130 Editeur: IEEE Document complet vers site de l'éditeur
» A Cascaded Coupled Inductor-Reverse High Step-Up Converter Integrating Three-Winding Coupled Inductor and Diode–Capacitor Technique
 Résumé:This paper introduces a cascaded high step-up converter realized with a tightly coupled three-winding coupled inductor. Compared with existing high step-up converters, the proposed converter features that the smaller the turns ratio, the larger the conversion gain. So, the name coupled inductor-reverse is given to represent reverse-coupled inductor principle of operation. In addition, diode–capacitor circuit is introduced to not only recycle leakage energy to output, but also further lift voltage conversion gain. This paper illustrates operation principle of the proposed converter, discusses effect of leakage inductance on voltage gain, and deduces voltage and current stresses of components. Finally, a prototype rated at 400 W has been established, and experimental results verify correctness of the above theoretical analysis. Auteurs: Fei Li;Hongchen Liu; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 06.-2017, volume: 13, issue:3, pages: 1121 - 1130 Editeur: IEEE Document complet vers site de l'éditeur
» A Characterization of Lyapunov Inequalities for Stability of Switched Systems
 Résumé:We study stability criteria for discrete-time switched systems and provide a meta-theorem that characterizes all Lyapunov theorems of a certain canonical type. For this purpose, we investigate the structure of sets of LMIs that provide a sufficient condition for stability. Various such conditions have been proposed in the literature in the past 15 years. We prove in this note that a family of language-theoretic conditions recently provided by the authors encapsulates all the possible LMI conditions, thus putting a conclusion to this research effort. As a corollary, we show that it is PSPACE-complete to recognize whether a particular set of LMIs implies stability of a switched system. Finally, we provide a geometric interpretation of these conditions, in terms of existence of an invariant set. Auteurs: Raphaël M. Jungers;Amir Ali Ahmadi;Pablo A. Parrilo;Mardavij Roozbehani; Apparue dans: IEEE Transactions on Automatic Control Date publication: 06.-2017, volume: 62, issue:6, pages: 3062 - 3067 Editeur: IEEE Document complet vers site de l'éditeur
» A Class of Weighted Quantized Kernel Recursive Least Squares Algorithms
 Résumé:In this brief, a class of weighted quantized kernel recursive least squares (WQKRLS) algorithms is proposed to efficiently improve the performance of online applications. In the proposed WQKRLS, an online vector quantization with weighted outputs is incorporated into quantized kernel recursive least squares. The resulting desired outputs are smoothed by exponential weights. In addition, the members of the dictionary are updated by the steepest descent method for further performance improvement. Simulations illustrate the superior performance of the proposed WQKRLS. Auteurs: Shiyuan Wang;Wanli Wang;Shukai Duan; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 06.-2017, volume: 64, issue:6, pages: 730 - 734 Editeur: IEEE Document complet vers site de l'éditeur
» A Closed-Loop Readout Configuration for Mode-Localized Resonant MEMS Sensors
 Résumé:This letter presents the first experimental results on the closed-loop characterization of a mode-localized microelectromechanical resonator system. Comparisons between the closed-loop oscillator approach and the open-loop frequency sweep approach show good agreement of output metrics including the amplitude ratios and mode frequencies. This new approach enables real-time measurements using emerging mode-localized resonant sensors and represents an important step toward realizing sensors based on this measurement principle. [2016-0307] Auteurs: Chun Zhao;Milind Pandit;Boqian Sun;Guillermo Sobreviela;Xudong Zou;Ashwin Seshia; Apparue dans: Journal of Microelectromechanical Systems Date publication: 06.-2017, volume: 26, issue:3, pages: 501 - 503 Editeur: IEEE Document complet vers site de l'éditeur
» A CMOS Compatible Ultracompact Silicon Photonic Optical Add-Drop Multiplexer with Misaligned Sidewall Bragg Gratings
 Résumé:We experimentally and via simulations demonstrate ultracompact single-stage and cascaded optical add-drop multiplexers using misaligned sidewall Bragg grating in a Mach–Zehnder interferometer for the silicon-on-insulator platform. The single-stage configuration has a device footprint of 400  ${\mu }\text{m}\,\times$ 90  ${\mu }\text{m}$, and the cascaded configuration has a footprint of 400 ${\mu }\text{m}\,\times$  125 ${\mu }\text{m}$. The proposed designs have 3-dB bandwidths of 6 nm and extinction ratios of 25 dB and 51 dB, respectively, and have been fabricated for the transverse electric mode. A minimum lithographic feature size of 80 nm is used in our design, which is within the limitation of 193 nm deep ultraviolet lithography. Auteurs: Md Ghulam Saber;Zhenping Xing;David Patel;Eslam El-Fiky;Nicolás Abadía;Yun Wang;Maxime Jacques;M. Morsy-Osman;David V. Plant; Apparue dans: IEEE Photonics Journal Date publication: 06.-2017, volume: 9, issue:3, pages: 1 - 10 Editeur: IEEE Document complet vers site de l'éditeur
» A CMOS Ultrawideband Pulse Generator for 3–5 GHz Applications
 Résumé:A low-power ultrawideband (UWB) pulse generator based on pulsed oscillator architecture for 3–5 GHz applications is proposed. The pulsed oscillator is improved, so it realizes binary phase shift keying (BPSK) modulation. Unlike ON–OFF keying or pulse-position modulation (PPM), BPSK can scramble the spectrum, so it can be used in high pulse rate applications without having spectral line problem. The signal structure in this design is burst mode of PPM+BPSK. The proposed UWB pulse generator was successfully implemented on 0.18- $\mu \text{m}$ CMOS technology. The peak-to-peak amplitude of output pulse is about 220 mV with 50- $\Omega$ load, the maximum power consumption is 4 mW at a raw data rate of 7.8 Mbps and the energy consumption is 32 pJ/pulse at a pulse rate of 125 Mpulses/s. Auteurs: Ruibing Dong;H. Kanaya;Ramesh K. Pokharel; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 06.-2017, volume: 27, issue:6, pages: 584 - 586 Editeur: IEEE Document complet vers site de l'éditeur
» A CNTFET Oscillator at 461 MHz
 Résumé:This letter presents design, implementation, and characterization of the first reported carbon nanotube field-effect transistor (CNTFET) RF oscillator. The circuit is implemented with discrete CNTFETs mounted on standard FR-4 substrate with off-the-shelf surface-mount-device components. The oscillator topology is similar to the phase shifter oscillator and uses two cascaded common source stages to provide enough gain for self-sustained and self-startup oscillation. The oscillator tank is merged with the matching network between two stages. The circuit oscillates at the frequency of 461 MHz with a phase noise of −115 dBc/Hz at 1 MHz and power consumption of 60 mW. While limited in output power by the driving capabilities of prototype CNTFETs, which still have a large density of residual metallic tubes, both power consumption and phase noise compare well with established and mature technologies. Moreover, the presented phase noise measurements provide a useful benchmark for the physical noise models being currently developed for this category of devices. Auteurs: A. Taghavi;C. Carta;T. Meister;F. Ellinger;M. Claus;M. Schroter; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 06.-2017, volume: 27, issue:6, pages: 578 - 580 Editeur: IEEE Document complet vers site de l'éditeur
» A Co-Simulation Scalar-Potential Finite Difference Method for the Numerical Analysis of Human Exposure to Magneto-Quasi-Static Fields
 Résumé:A two-step approach for the simulation of the exposure of a human body to magneto-quasi-static fields is presented. The co-simulation scalar-potential finite difference method is a calculation scheme, where a distribution of the magnetic vector potential inside the biological tissues is derived from a free space magnetic source field simulation using a tree-cotree gauging algorithm. With the obtained magnetic vector potential, the electric field strength inside the voxel representation of the biological tissues is calculated solving a high-dimensional discrete Poisson equation on a high-performance workstation with multiple graphics processing units (GPUs). An exposure scenario, including an inductive power transfer system, a car model, and an anatomical human body voxel model, is simulated using this approach, and the results are compared with a monolithic scaled-frequency finite difference time domain simulation. The maximum body-internal electric field strength (voxel average) is determined and compared with basic restrictions recommended by the International Commission on Non-Ionizing Radiation Protection. Auteurs: Martin Zang;Carsten Cimala;Markus Clemens;Jennifer Dutiné;Thomas Timm;Benedikt Schmuelling; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» A Coalition Formation Game for Distributed Node Clustering in Mobile Ad Hoc Networks
 Résumé:In the context of wireless mobile ad hoc networks, node clustering is a well-known solution for handling the scalability issue. While existing work focused on unstructured (i.e., flat) networks, this paper investigates a clustering algorithm to handle stable size-restricted clusters for structured (i.e., group-based) networks. In addition, we have identified that the ad hoc network clustering literature lacks a theoretical framework. This paper fills this gap by proposing to use coalition game theory, identifying coalitions to clusters and players to nodes. This theoretical framework allows us to derive a novel generic distributed node clustering algorithm. The algorithm is proved to converge to Nash-stable partitions. It is based on the concept of switch operations, where nodes take decision whether to leave or not their current coalition based on the coalition values. These decisions are made independently on any node individual payoff, meaning that the coalition formation game has a transferable utility. This generic algorithm is then tailored to both structured and unstructured networks, by defining judiciously the value functions and the heuristics dedicated to selecting suitable switch operations. Based on extensive simulations, we show that our proposed solutions outperform the existing ones especially in terms of cluster size and stability. Auteurs: Raphaël Massin;Christophe J. Le Martret;Philippe Ciblat; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 06.-2017, volume: 16, issue:6, pages: 3940 - 3952 Editeur: IEEE Document complet vers site de l'éditeur
» A Combined Prognostic Model Based on Machine Learning for Tidal Current Prediction
 Résumé:This paper proposes a univariate prognostic approach based on wavelet transform and support vector regression (SVR) to predict the tidal current speed and direction with high accuracy. The proposed model decomposes the tidal current data into some subharmonic components. The details and approximation components are later fed to several SVR models to attend the prediction process. In order to increase the robustness of the model, the idea of combined prediction is used to model each subharmonic signal by several SVRs. The median operator is further used to determine the aggregated forecast tidal current data. Due to the high reliance of SVR model on the kernel function and hyperplane parameters, a new optimization method based on the bat algorithm is used to train the SVR model. The final forecast tidal current data are constructed using an aggregation operator in the output of the SVRs. The accuracy and satisfying performance of the proposed model are examined on the practical tidal data collected from the Bay of Fundy, NS, Canada. The experimental results reveal the high capability and robustness of the proposed hybrid model for the tidal current prediction. Auteurs: Abdollah Kavousi-Fard;Wencong Su; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 06.-2017, volume: 55, issue:6, pages: 3108 - 3114 Editeur: IEEE Document complet vers site de l'éditeur
» A Communication Theoretical Analysis of Multiple-Access Channel Capacity in Magneto-Inductive Wireless Networks
 Résumé:Magneto-inductive (MI) wireless communications is an emerging subject with a rich set of applications, including local area networks for the Internet-of-Things, wireless body area networks, in-body and on-chip communications, and underwater and underground sensor networks as a low-cost alternative to radio frequency, acoustic or optical methods. Practical MI networks include multiple access channel (MAC) mechanisms for connecting a random number of coils without any specific topology or coil orientation assumptions covering both short and long ranges. However, there is not any information theoretical modeling of MI MAC (MIMAC) capacity of such universal networks with fully coupled frequency selective channel models and exact 3-D coupling model of circular coils instead of long range dipole approximations. In this paper, K-user MIMAC capacity is information theoretically modeled and analyzed, and two-user MIMACs are modeled with explicitly detailed channel responses, bandwidths and coupled thermal noise. K-user MIMAC capacity is achieved through Lagrangian solution with K-user water-filling optimization. Optimum orientations maximizing capacity and received power are theoretically analyzed, and numerically simulated for two-user MIMACs. Constructive gain and destructive interference mechanisms on MIMACs are introduced in comparison with the classical interference based approaches. The theoretical basis promises the utilization of MIMACs in 5G architectures. Auteurs: Burhan Gulbahar; Apparue dans: IEEE Transactions on Communications Date publication: 06.-2017, volume: 65, issue:6, pages: 2594 - 2607 Editeur: IEEE Document complet vers site de l'éditeur
» A Compact Broadband Mixed-Signal Power Amplifier in Bulk CMOS With Hybrid Class-G and Dynamic Load Trajectory Manipulation
 Résumé:This paper presents a mixed-signal power amplifier (PA) with real-time hybrid Class-G and dynamic load trajectory manipulation (DLTM) operation that achieves PA efficiency enhancement into the deep power back-off (PBO) region. Moreover, we dynamically manipulate the PA load impedance trajectory that travels from the optimum output power (Pout) load impedance to the optimum efficiency load impedance during PBO, which creates PA PBO efficiency peaking. The introduced digitally intensive mixed-signal PA architecture enables precise and optimum real-time hybrid PA operation and ensures both PA output amplitude and phase accuracy. DLTM operation also extends the PA RF carrier bandwidth. A prototype PA is fully integrated in a standard 65-nm bulk CMOS process. Its load modulation network is realized by an on-chip compact transformer balun and two on-chip switch-controlled capacitors. The PA achieves +24.6-dBm (+24.4-dBm) peak Pout and 45.6% (45.8%) maximum drain efficiency (DE) at 2.4 GHz (2.8 GHz). DLTM operation extends the PA Pout and 1-dB bandwidth from 41.7% to 53.8%. By combining the real-time hybrid Class-G and DLTM operation with mixed-signal linearization, the PA delivers +17.6/+17.3-dBm (+17.3/+17-dBm) 10M-Sym/s 64QAM/256QAM at 2.4 GHz (2.8 GHz) with 27.5/26.7% (26.2/24.1%) DE, -29.2/-30.4-dB (-31.3/-31.5 dB) rms error vector magnitude (EVM), and -25.3/-25.1-dBc (-26.4/-26.1-dBc) adjacent channel leakage ratio (ACLR). The total chip area is 1.9 mm^2. Auteurs: Song Hu;Shouhei Kousai;Hua Wang; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1463 - 1478 Editeur: IEEE Document complet vers site de l'éditeur
» A Compact Synchronous Cellular Model of Nonlinear Calcium Dynamics: Simulation and FPGA Synthesis Results
 Résumé:Recent studies have demonstrated that calcium is a widespread intracellular ion that controls a wide range of temporal dynamics in the mammalian body. The simulation and validation of such studies using experimental data would benefit from a fast large scale simulation and modelling tool. This paper presents a compact and fully reconfigurable cellular calcium model capable of mimicking Hopf bifurcation phenomenon and various nonlinear responses of the biological calcium dynamics. The proposed cellular model is synthesized on a digital platform for a single unit and a network model. Hardware synthesis, physical implementation on FPGA, and theoretical analysis confirm that the proposed cellular model can mimic the biological calcium behaviors with considerably low hardware overhead. The approach has the potential to speed up large-scale simulations of slow intracellular dynamics by sharing more cellular units in real-time. To this end, various networks constructed by pipelining 10 k to 40 k cellular calcium units are compared with an equivalent simulation run on a standard PC workstation. Results show that the cellular hardware model is, on average, 83 times faster than the CPU version. Auteurs: Hamid Soleimani;Emmanuel M. Drakakis; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 703 - 713 Editeur: IEEE Document complet vers site de l'éditeur
» A Comparative Study of Surface Integral Equations for Accurate and Efficient Analysis of Plasmonic Structures
 Résumé:Surface integral equations, which are commonly used in electromagnetic simulations, have recently been applied to various plasmonic problems, while there is still no complete agreement on which formulations provide accurate and efficient solutions. In this paper, we present the strong material dependences of the conventional formulations, revealing their contradictory performances for different problems. We further explain the numerical problems in the constructed matrix equations, shedding light on the design of alternative formulations that can be more accurate, efficient, and stable than the existing ones. Based on our observations in the limit cases, we present a new formulation, namely, a modified combined-tangential formulation (MCTF), which provides stable solutions of plasmonic problems in wide ranges of negative permittivity values. The favorable properties of MCTF in comparison to other formulations are demonstrated not only on canonical problems but also on realistic cases involving nanowires. Auteurs: Barışcan Karaosmanoğlu;Akif Yılmaz;Özgür Ergül; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3049 - 3057 Editeur: IEEE Document complet vers site de l'éditeur
» A Comparison Between Three Sparse Unmixing Algorithms Using a Large Library of Shortwave Infrared Mineral Spectra
 Résumé:The comparison described in this paper has been motivated by two things: 1) a “spectral library” of shortwave infrared reflectance spectra that we have built, consisting of the spectra of 60 nominally pure materials (mostly minerals, but also water, dry vegetation, and several man-made materials) and 2) the needs of users in the mining industry for the use of fast and accurate unmixing software to analyze tens to hundreds of thousands of spectra measured from drill core or chips using HyLogging instruments, and other commercial reflectance spectrometers. Individual samples are typically a mixture of only one, two, three, or occasionally four minerals. Therefore, in order to avoid overfitting, a sparse unmixing algorithm is required. We compare three such algorithms using some real world test data sets: full subset selection (FSS), sparse demixing (SD), and L1 regularization. To aid the comparison, we introduce two novel aspects: 1) the simultaneous fitting of the low frequency background with mineral identification (which provides greater model flexibility) and 2) the combined fitting being carried out using a suitably defined Mahalanobis distance; this has certain optimality properties under an idealized model. Together, these two innovations significantly improve the accuracy of the results. FSS and L1 regularization (suitably optimized) produce similar levels of accuracy, and are superior to SD. Discussion includes possible improvements to the algorithms, and their possible use in other domains. Auteurs: Mark Berman;Leanne Bischof;Ryan Lagerstrom;Yi Guo;Jon Huntington;Peter Mason;Andrew A. Green; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 06.-2017, volume: 55, issue:6, pages: 3588 - 3610 Editeur: IEEE Document complet vers site de l'éditeur
» A Comparison of Two Current Transformer Calibration Systems at NRC Canada
 Résumé:A comparison of two systems based on different methods for calibration of current transformers at several different transformation ratios, burdens, and power frequencies of 60 Hz and 50 Hz is performed at the National Research Council of Canada. The obtained discrepancies in ratio and phase errors are within $5~mu text{A}$ /A and $mu$ rad, respectively, for small test currents and less for larger test currents. Auteurs: Branislav V. Djokić;Harold Parks;Nicholas Wise;Dragana Naumović-Vuković;Slobodan P. Škundrić;Aleksandar D. Žigić;Vladimir Polužanski; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 06.-2017, volume: 66, issue:6, pages: 1628 - 1635 Editeur: IEEE Document complet vers site de l'éditeur
» A Comparison Study for the Estimation of SOFC Internal Dynamic States in Complex Power Systems Using Filtering Algorithms
 Résumé:This paper enumerates three commonly used filtering algorithms and shows the detailed steps of their incorporation with general nonlinear systems for dynamic state estimation. The mathematical model of a stand-alone solid oxide fuel cell (SOFC) is briefly discussed and derived, which is then mathematically connected to a multiarea, diverse-generator, interconnected complex test system. The mathematical representation of the entire power system is tailored into a certain compact form to provide suitability for the implementation of filtering algorithms for the design of dynamic state estimators. With the utilization of phasor measurement units, the state estimators are able to work in a decentralized manner with the mere knowledge of local noisy voltage and current measurements. Successfully estimating the internal dynamic states of SOFC connected to complex power systems offers a novel methodology for the acquisition of the internal unmeasurable states of SOFC, which will facilitate future controller designs that may require the otherwise inaccessible states. Auteurs: Shenglong Yu;Tyrone Fernando;Herbert Ho-Ching Iu; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 06.-2017, volume: 13, issue:3, pages: 1027 - 1035 Editeur: IEEE Document complet vers site de l'éditeur
» A Computational Study of Efficiency Map Calculation for Synchronous AC Motor Drives Including Cross-Coupling and Saturation Effects
 Résumé:After designing and optimizing an electric machine, efficiency maps are needed to predict a vehicle’s performance in a dynamic simulation. Calculating efficiencies at various torque and speed points, however, requires prior knowledge of the input excitation conditions, such as the current magnitude and advance angle, in an electromagnetic finite-element analysis simulation. Hence, this paper derives and uses nonlinear motor control equations (MTPA, FW, MTPV) in the study of efficiency map calculation while accounting for both saturation and cross-coupling effects. Two synchronous ac motors are considered in this paper, including the 2010 Prius IPM and a PM-assisted synchronous reluctance machine, with all procedure steps outlined in detail. Auteurs: Mohammad Hossain Mohammadi;David Alister Lowther; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» A Computer Aided Education System Based on Augmented Reality by Immersion to 3-D Magnetic Field
 Résumé:An immersive real-time visualization system of 3-D magnetic field for educational purposes is presented. This immersive visualization system is based on augmented reality technology. The proposed system provides observation of a magnetic field distribution and its stereoscopic vision in 3-D space using head mounted display. To improve the visualization capabilities, a new real-time method for drawing magnetic flux lines in 3-D space is developed and presented in this paper. It enables a user to easily observe and grasp a magnetic field generated by multiple sources (e.g., magnets and/or multiple coils) in an augmented 3-D space. Additionally, it permits a user to freely and interactively move the magnetic sources within the visualization space and to observe the magnetic fields interference in real-time. As a result, one can intuitively and easy visualize, observe and grasp the magnetic field even in 3-D space. Auteurs: Shinya Matsutomo;Tomohisa Manabe;Vlatko Cingoski;So Noguchi; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» A Computer-Controlled Calibrator for Instrument Transformer Test Sets
 Résumé:In recent years, test sets for both conventional and analog nonconventional instrument transformers have been made commercially available. Reference transformers are still of the conventional type. Therefore, test sets need to compare an analog signal of a conventional level with another analog signal of a different order of magnitude or, in the case of current-to-voltage transformers, even a different quantity. Traditional designs based on bridge techniques are not suitable for this application. This paper describes a new calibrator that reaches uncertainties of the order of $10\times 10^{-6}$ while being suitable for the calibration of test sets for nonconventional analog instrument transformers and fully computer-controlled. Auteurs: Stefan Siegenthaler;Christian Mester; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 06.-2017, volume: 66, issue:6, pages: 1184 - 1190 Editeur: IEEE Document complet vers site de l'éditeur
» A Convex Characterization of Multidimensional Linear Systems Subject to SQI Constraints
 Résumé:This technical note proposes a convex characterization of the set of all stable closed-loop linear systems that are obtained from a given plant, which may be multidimensional, by interconnecting it in feedback with controllers that satisfy a certain pre-selected constraint. We take an approach that is particularly useful when a doubly-coprime factorization of the plant is difficult to obtain, and a stable stabilizing controller may not exist (the plant is not strongly-stabilizable) or when one may be difficult to find; most related work requires one of these. We adopt the so-called coordinate-free approach, which, unlike Youla's parametrization, does not rely on a doubly-coprime factorization of the plant. We show that if constraints which satisfy a condition called strong quadratic invariance (SQI) are imposed on the controllers then the set of all stable closed-loop multidimensional linear systems has a convex representation, and norm-optimal control problems can be cast in convex form. Although the SQI condition is in general slightly stronger than quadratic invariance (QI), which was developed in related work, they are equivalent for common classes of problems arising in decentralized control. Auteurs: Şerban Sabău;Nuno C. Martins;Michael C. Rotkowitz; Apparue dans: IEEE Transactions on Automatic Control Date publication: 06.-2017, volume: 62, issue:6, pages: 2981 - 2986 Editeur: IEEE Document complet vers site de l'éditeur
» A Convolutional PML Scheme for the Efficient Modeling of Graphene Structures Through the ADE-FDTD Technique
 Résumé:The development of an accurate convolutional perfectly matched layer for the efficient termination of infinite graphene structures is introduced in this paper. Initially, the popular 2-D material receives the appropriate theoretical analysis, which reveals the necessity of a flexible terminating condition that can enhance the performance of existing absorbing schemes and offer sufficient truncation rates for the graphene’s strongly confined surface waves. The consistency and behavior of the novel technique are substantiated via comprehensive comparisons with setups truncated by conventional absorbing boundary conditions. Finally, a graphene microribbon waveguide is addressed to indicate the capabilities of featured algorithm in complex structures. Auteurs: Athanasios N. Papadimopoulos;Stamatios A. Amanatiadis;Nikolaos V. Kantartzis;Ioannis T. Rekanos;Theodoros T. Zygiridis;Theodoros D. Tsiboukis; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» A Cooperative SWIPT Scheme for Wirelessly Powered Sensor Networks
 Résumé:Wireless power transfer (WPT) provides a novel solution to the painstaking power-charging issue in wireless sensor networks. However, due to the propagation loss, the fast attenuation in energy transfer efficiency over the transmission distance is the main impediment to the WPT application. In this paper, we apply the simultaneous wireless information and power transfer (SWIPT) to a wirelessly powered sensor network, where each node has two circuits, which operate on energy harvesting mode and information decoding mode separately. We propose a novel cooperative SWIPT scheme (CSS) for this system. First, we present a conflict-free schedule initialization algorithm for CSS. For a given conflict-free schedule, we formulate a resource allocation problem to maximize the network energy efficiency, which is then transformed to an equivalent convex optimization problem and resolved via dual decomposition. Finally, a heuristic algorithm is presented to achieve the transmission schedule with the maximum energy efficiency and the corresponding resource assignment policy. Simulation results indicate that the CSS can significantly improve the energy efficiency of the wirelessly powered sensor network. Auteurs: Tao Liu;Xiaodong Wang;Le Zheng; Apparue dans: IEEE Transactions on Communications Date publication: 06.-2017, volume: 65, issue:6, pages: 2740 - 2752 Editeur: IEEE Document complet vers site de l'éditeur
» A Coupled Circuit-Ambipolar Diffusion Equation Model and Its Solution Methodology for Insulated Gate Bipolar Transistors
 Résumé:To eliminate the inefficiencies of the existing physics-based planar-gate insulated gate bipolar transistor (IGBT) model without considering an arbitrary free-carrier injection condition and 2-D effects at the MOS end of the drift region in the transient performance simulations, a coupled circuit-ambipolar diffusion equation model and its numerical solution methodology is proposed. Moreover, the proposed model treads the nonlinearity in a complete transient manner. The accuracy of the proposed model is validated by comparing the computed results with both experimental ones and those of an existing model. Auteurs: Jiajia Chen;Jiaqiang Yang;Shiyou Yang;Xingjian Li; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» A Coupled Method for Evaluating Eddy Current Loss of NdFeB Permanent Magnets in a Saturated Core Fault Current Limiter
 Résumé:Eddy-current loss of NdFeB permanent magnets (PMs) is widely analyzed in PM motors. This paper proposes a coupled 2-D transient finite-element analysis (FEA) of the saturated core fault current limiter (SCFCL) and 3-D analytical model of PMs to evaluate eddy-current loss in SCFCL. The comparison between the result from coupled method and that from 3-D FEA verifies the applicability of the coupled method in analyzing eddy current loss of PMs in SCFCL. The 3-D analytical model of PM is applied to analyze the effect of segmentation on the reduction of PM’s eddy-current loss. And the results show that segmentation along width has a better performance, which is also verified by 3-D FEA. Auteurs: Cuihua Tian;Yongheng Zhong;Liangliang Wei;Yang Lei;Baichao Chen;Yanhui Gao;Kazuhiro Muramatsu;Jiaxin Yuan; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» A Crawling Magnetic Robot Actuated and Steered via Oscillatory Rotating External Magnetic Fields in Tubular Environments
 Résumé:We propose a novel crawling magnetic robot and a driving method utilizing an oscillatory rotating external magnetic field. The crawling magnetic robot is composed of an actuating body with a permanent magnet, two steering bodies with permanent magnets, and flexible legs. The proposed crawling magnetic robot can increase actuating torque with long cylindrical magnet to crawl in tubular environments and navigate in pulsatile flow more than conventional spiral robots. The rotating external magnetic field synchronizes the driving plane of the crawling magnetic robot with the oscillating external magnetic field, while the oscillating external magnetic field generates actuating motion in order to stably generate the crawling motion at any posture. Finally, we prototyped the crawling magnetic robot, and verified the effectiveness of the proposed crawling magnetic robot and driving method in various tubular environments. Auteurs: Bongjun Jang;Jaekwang Nam;Wonseo Lee;Gunhee Jang; Apparue dans: IEEE/ASME Transactions on Mechatronics Date publication: 06.-2017, volume: 22, issue:3, pages: 1465 - 1472 Editeur: IEEE Document complet vers site de l'éditeur
» A Crowd-Cooperative Approach for Intelligent Transportation Systems
 Résumé:As embedded and mobile systems grow pervasive in people lives and expand their reach, paradigms related to mobile crowdsensing (MCS) are going to play an ever more prominent role. Innovative methodologies and applications able to unlock such a huge potential are required. A domain where MCS really fits is mobility and transportation. However, for a full exploitation of this paradigm in intelligent transportation systems (ITS), distributed and self-management capabilities for the involved nodes-vehicles have to be provided. This paper is a first step in this direction, laying out an optimization system by exploiting feedback-driven patterns in a distributed-opportunistic way. In this sense, collective intelligence and stigmergic, swarm-based paradigms are adapted to an innovative decentralized MCS pattern toward new approaches in ITS. Their effectiveness is demonstrated through a traffic engineering case study, where route planning services are designed according to the proposed approach and then modeled and evaluated by Markovian agents. Auteurs: Davide Cerotti;Salvatore Distefano;Giovanni Merlino;Antonio Puliafito; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 06.-2017, volume: 18, issue:6, pages: 1529 - 1539 Editeur: IEEE Document complet vers site de l'éditeur
» A d–q Voltage Droop Control Method With Dynamically Phase-Shifted Phase-Locked Loop for Inverter Paralleling Without Any Communication Between Individual Inverters
 Résumé:This paper presents a modified droop control method for equal load sharing of parallel-connected inverters, without any communication between individual inverters. Droop in d- and q-axis voltages are given depending upon d- and q-axis currents, respectively. Each inverter works in the voltage control mode, where it controls the filter capacitor voltage. Voltage references of each inverter come from d- and q-axis voltage droops. This d- and q -axis voltage droops force the parallel-connected inverters to share equal current and hence equal active and reactive power. A dynamically phase-shifted phase-locked loop (PLL) technique is locally designed for generating phase reference of each inverter. The phase angle between filter capacitor voltage vector and d-axis is dynamically adjusted with the change in q-axis inverter current to generate the phase reference of each inverter. The strategy has been verified with simulations and experiments and results are presented in this paper. Auteurs: Partha Pratim Das;Souvik Chattopadhayay;Manas Palmal; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 06.-2017, volume: 64, issue:6, pages: 4591 - 4600 Editeur: IEEE Document complet vers site de l'éditeur
» A Dagstuhl Seminar Looks beyond Virtual and Augmented Reality
 Résumé:At a five-day seminar in Germany, 30 researchers came together to discuss the future of interactive media. Motivated by the third wave of virtual and augmented reality technologies, the goal was to take a step back from technical research to look at the fundamental aspects of interactive media. The seminar featured initial talks by all attendees; several breakout sessions; hands-on workshops on novel experience-sharing technologies; and panel discussions on human-computer symbiosis, human augmentation, and enabling technologies. Auteurs: Niels Henze;Kai Kunze; Apparue dans: IEEE Multimedia Date publication: 06.-2017, volume: 24, issue:2, pages: 14 - 17 Editeur: IEEE Document complet vers site de l'éditeur
» A Data-Driven Health Monitoring Method for Satellite Housekeeping Data Based on Probabilistic Clustering and Dimensionality Reduction
 Résumé:In the operation of artificial satellites, it is very important to monitor the health status of the systems and detect any symptoms of anomalies in the housekeeping data as soon as possible. Recently, the data-driven approach to the system monitoring problem, in which statistical machine learning techniques are applied to the large amount of measurement data collected in the past, has attracted considerable attention. In this paper, we propose a new data-driven health monitoring and anomaly detection method for artificial satellites based on probabilistic dimensionality reduction and clustering, taking into consideration the miscellaneous characteristics of the spacecraft housekeeping data. We applied our method to the telemetry data of the small demonstration satellite 4 (SDS-4) of the Japan Aerospace Exploration Agency (JAXA) and evaluated its effectiveness. The results show that the proposed system provides satellite operators with valuable information for understanding the health status of the system and inferring the causes of anomalies. Auteurs: Takehisa Yairi;Naoya Takeishi;Tetsuo Oda;Yuta Nakajima;Naoki Nishimura;Noboru Takata; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 06.-2017, volume: 53, issue:3, pages: 1384 - 1401 Editeur: IEEE Document complet vers site de l'éditeur
» A DCT-Based Total JND Profile for Spatiotemporal and Foveated Masking Effects
 Résumé:In image and video processing fields, Discrete Cosine Transform (DCT)-based just-noticeable difference (JND) profiles have effectively been utilized to remove perceptual redundancies in pictures for compression. In this paper, we solve two problems that are often intrinsic to the conventional DCT-based JND profiles: 1) no foveated masking (FM) JND model has been incorporated in modeling the DCT-based JND profiles and 2) the conventional temporal masking (TM) JND models assume that all moving objects in frames can be well tracked by the eyes and that they are projected on the fovea regions of the eyes, which is not a realistic assumption and may result in poor estimation of JND values for untracked moving objects (or image regions). To solve these two problems, we first propose a generalized JND model for joint effects between TM and FM effects. With this model, called the temporal–foveated masking (TFM) JND model, JND thresholds for any tracked/untracked and moving/still image regions can be elaborately estimated. Finally, the TFM-JND model is incorporated into a total DCT-based JND profile with a spatial contrast sensitivity function, luminance masking, and contrast masking JND models. In addition, we propose a JND adjustment method for our total JND profile to avoid overestimation of JND values for image blocks of fixed sizes with various image characteristics. To validate the effectiveness of the total JND profile, an experiment involving a subjective distortion-visibility assessment has been conducted. The experiment results show that the proposed total DCT-based JND profile yields significant performance improvement with much higher capability of distortion concealment (average 5.6-dB lower PSNR) compared with state-of-the-art JND profiles. The MATLAB source code of the proposed total DCT-based JND profile is publicly available online at https://sites.google.com/site/sunghobaecv/jnd. Auteurs: Sung-Ho Bae;Munchurl Kim; Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology Date publication: 06.-2017, volume: 27, issue:6, pages: 1196 - 1207 Editeur: IEEE Document complet vers site de l'éditeur
» A Decision-Directed Channel Estimator for OFDM-Based Bursty Vehicular Communication
 Résumé:We consider bursty orthogonal frequency-division multiplexing (OFDM) signal transmission, where each signal burst (or packet) consists of a preamble followed by data symbols which may contain few pilots. Channel estimation in vehicular environments for such signals is a challenging issue, as evidenced by related studies for the IEEE 802.11p standard. Existing channel estimation methods often yield deficient performance or require relatively high latency to achieve better performance, unless additional pilots are introduced. We propose a technique that addresses this problem. The primary aspect of the design is to exploit the temporal correlation in channel responses over close-by OFDM symbols in a decision-oriented manner. A secondary aspect is to take advantage of any available pilots in the data symbols in a frequency-domain filtering built on the temporal processing results. Regarding the performance of the proposed method, we first analyze the proposed temporal processing technique under some simplistic channel conditions both for insight and for verification. Further simulation results based on the IEEE 802.11p specifications under a measurement-based fading multipath vehicle-to-vehicle (V2V) channel model show the superiority of the proposed method. Auteurs: Chunfan Wei;David W. Lin; Apparue dans: IEEE Transactions on Vehicular Technology Date publication: 06.-2017, volume: 66, issue:6, pages: 4938 - 4953 Editeur: IEEE Document complet vers site de l'éditeur
» A Design of U-Shaped Slot Antenna With Broadband Dual Circularly Polarized Radiation
 Résumé:In this communication, a novel broadband dual circularly polarized (CP) antenna is presented. This antenna consists of an U-shaped slot to achieve broadband CP radiation and two 50- $\Omega$ microstrip-fed ports to realize both right-hand circular polarization and left-hand circular polarization at the same frequency band. The axial ratio bandwidth (ARBW) is greatly broadened by moving the feeding ports to upper portion of the U-shaped slot. To verify this design, the proposed antenna is fabricated and measured. The measured −10 dB reflection coefficient bandwidth is about 114.4% (1.80–6.61 GHz) and the 3-dB ARBW is approximately 110.5% (1.83–6.35 GHz). The isolation between two ports is better than 14.8 dB within the ARBW. Auteurs: Rui Xu;Jian-Ying Li;Jiang-Jun Yang;Kun Wei;Yang-Xiao Qi; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3217 - 3220 Editeur: IEEE Document complet vers site de l'éditeur
» A Digital Five-Terminal Impedance Bridge
 Résumé:This paper describes a five-terminal (four terminal with shield) digital impedance bridge aided by digital adaptive phase regulation. It allows the comparison of ac resistances and capacitances with outstanding accuracy and with measurement uncertainties bearing only some $10^{\mathrm { {-6}}} \Omega /\Omega$ , as corroborated by extensive experimental investigations. Auteurs: Waldemar G. Kürte Ihlenfeld;Renata T. de Barros e Vasconcellos; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 06.-2017, volume: 66, issue:6, pages: 1546 - 1552 Editeur: IEEE Document complet vers site de l'éditeur
» A Discontinuous Galerkin Time-Domain Method With Dynamically Adaptive Cartesian Mesh for Computational Electromagnetics
 Résumé:A discontinuous Galerkin time-domain (DGTD) method based on dynamically adaptive Cartesian mesh (ACM) is developed for a full-wave analysis of electromagnetic (EM) fields. The benefits of hierarchical Cartesian grids and adaptive mesh refinement are demonstrated for linear EM propagation problems. The developed DGTD-ACM achieves a desired accuracy by refining nonconformal meshes near material interfaces to reduce stair-casing errors without sacrificing the high efficiency afforded with uniform Cartesian meshes. More importantly, DGTD-ACM can dynamically refine the mesh to resolve the local variation of the fields during propagation of EM pulses. A local time-stepping scheme is adopted to alleviate the constraint on the time-step size due to the stability condition of the explicit time integration. It is shown by numerical examples that the proposed method can achieve a good numerical accuracy and reduce the computational time effectively for linear problems of EM propagation in dispersive media. With further development, the method is expected to provide a powerful tool for solving nonlinear EM problems in plasma physics and electronics. Auteurs: Su Yan;Chao-Ping Lin;Robert R. Arslanbekov;Vladimir I. Kolobov;Jian-Ming Jin; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3122 - 3133 Editeur: IEEE Document complet vers site de l'éditeur
» A Discretization Method With the $H_{\mathrm{ div}}$ Inner Product for Electric Field Integral Equations
 Résumé:A discretization method with the $H_{\mathrm{ div}}$ inner product for the electric field integral equation (EFIE) is proposed. The EFIE with the conventional Galerkin discretization shows bad accuracy for problems with a small frequency, a problem known as the low-frequency breakdown. The discretization method proposed in this paper utilizes the $H_{\mathrm{ div}}$ scalar product with a scalar coefficient for the Galerkin discretization and overcomes the low-frequency problem with an appropriately chosen coefficient. As regards the preconditioning, we find that a naive use of the widely used Calderón preconditioning is not efficient for reducing the computational time with the new discretization. We therefore propose a new preconditioning which can accelerate the computation successfully. The efficiency of the proposed discretization and preconditioning is verified through some numerical examples. Auteurs: Kazuki Niino;Sho Akagi;Naoshi Nishimura; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3102 - 3113 Editeur: IEEE Document complet vers site de l'éditeur
» A Discretization Method With the $H_{\mathrm{ div}}$ Inner Product for Electric Field Integral Equations
 Résumé:A discretization method with the $H_{\mathrm{ div}}$ inner product for the electric field integral equation (EFIE) is proposed. The EFIE with the conventional Galerkin discretization shows bad accuracy for problems with a small frequency, a problem known as the low-frequency breakdown. The discretization method proposed in this paper utilizes the $H_{\mathrm{ div}}$ scalar product with a scalar coefficient for the Galerkin discretization and overcomes the low-frequency problem with an appropriately chosen coefficient. As regards the preconditioning, we find that a naive use of the widely used Calderón preconditioning is not efficient for reducing the computational time with the new discretization. We therefore propose a new preconditioning which can accelerate the computation successfully. The efficiency of the proposed discretization and preconditioning is verified through some numerical examples. Auteurs: Kazuki Niino;Sho Akagi;Naoshi Nishimura; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3102 - 3113 Editeur: IEEE Document complet vers site de l'éditeur
» A Discretization Method With the $H_{\mathrm{ div}}$ Inner Product for Electric Field Integral Equations
 Résumé:A discretization method with the Hdiv inner product for the electric field integral equation (EFIE) is proposed. The EFIE with the conventional Galerkin discretization shows bad accuracy for problems with a small frequency, a problem known as the low-frequency breakdown. The discretization method proposed in this paper utilizes the Hdiv scalar product with a scalar coefficient for the Galerkin discretization and overcomes the low-frequency problem with an appropriately chosen coefficient. As regards the preconditioning, we find that a naive use of the widely used Calderón preconditioning is not efficient for reducing the computational time with the new discretization. We therefore propose a new preconditioning which can accelerate the computation successfully. The efficiency of the proposed discretization and preconditioning is verified through some numerical examples. Auteurs: Kazuki Niino;Sho Akagi;Naoshi Nishimura; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3102 - 3113 Editeur: IEEE Document complet vers site de l'éditeur
» A Distributed Algorithm for Economic Dispatch Over Time-Varying Directed Networks With Delays
 Résumé:In power system operation, the economic dispatch problem (EDP) aims to minimize the total generation cost while meeting the demand and satisfying generator capacity limits. This paper proposes an algorithm based on the gradient push-sum method to solve the EDP in a distributed manner over communication networks potentially with time-varying topologies and communication delays. This paper shows that the proposed algorithm is guaranteed to solve the EDP if the time-varying directed communication network is uniformly jointly strongly connected. Moreover, the proposed algorithm is also able to handle arbitrarily large but bounded time-varying delays on communication links. Numerical simulations are used to illustrate and validate the proposed algorithm. Auteurs: Tao Yang;Jie Lu;Di Wu;Junfeng Wu;Guodong Shi;Ziyang Meng;Karl Henrik Johansson; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 06.-2017, volume: 64, issue:6, pages: 5095 - 5106 Editeur: IEEE Document complet vers site de l'éditeur
» A Distributed Learning Automata Scheme for Spectrum Management in Self-Organized Cognitive Radio Network
 Résumé:We propose a distributed Learning Automata (LA) for spectrum management problem in Cognitive Radio (CR) networks. The objective is to design intelligent Secondary Users (SUs) which can interact with the RF environment and learn from its different responses through the sensing. It is assumed there is no prior information about the Primary Users (PUs) and other SUs activities while there is no information exchange among SUs. Each SU is empowered with an LA which operates in the RF environment with different responses. That is, the SUs are considered as agents in a self-organized system which select one channel as an action and receive different responses from the environment based on how much their selected actions are favorable or unfavorable. Using these responses, SUs control their accesses to the channels for appropriate spectrum management with the objective to incur less communication delay, less interference with PUs, and less interference with other SUs. The proposed LA-based distributed algorithm is investigated in terms of asymptotic convergence and stability. Simulation results are provided to show the performance of the proposed scheme in terms of SUs’ waiting times, interference with other SUs, the number of interruptions by PUs during their transmissions, and fairness. Auteurs: Mina Fahimi;Abdorasoul Ghasemi; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 06.-2017, volume: 16, issue:6, pages: 1490 - 1501 Editeur: IEEE Document complet vers site de l'éditeur
» A Distributed Monitoring Strategy for Detecting Version Number Attacks in RPL-Based Networks
 Résumé:The Internet of Things is characterized by the large-scale deployment of low power and lossy networks (LLN), interconnecting pervasive objects. The routing protocol for LLN (RPL) protocol has been standardized by IETF to enable a lightweight and robust routing in these constrained networks. A versioning mechanism is incorporated into RPL in order to maintain an optimized topology. However, an attacker can exploit this mechanism to significantly damage the network and reduce its lifetime. After analyzing and comparing existing work, we propose in this paper a monitoring strategy with dedicated algorithms for detecting such attacks and identifying the involved malicious nodes. The performance of this solution is evaluated through extensive experiments, and its scalability is quantified with the support of a monitoring node placement optimization method. Auteurs: Anthéa Mayzaud;Rémi Badonnel;Isabelle Chrisment; Apparue dans: IEEE Transactions on Network and Service Management Date publication: 06.-2017, volume: 14, issue:2, pages: 472 - 486 Editeur: IEEE Document complet vers site de l'éditeur
» A Driving Method of Pixel Circuit Using a-IGZO TFT for Suppression of Threshold Voltage Shift in AMLED Displays
 Résumé:A driving method of pixel circuit using amorphous indium gallium zinc oxide (a-IGZO) thin-film transistor (TFT) is proposed to improve the image quality of active matrix light-emitting diode displays. The proposed pixel circuit employs a diode-connected structure to compensate for variation in threshold voltage ( $V_{\sf {th}}$ ) of the a-IGZO TFT. In addition, the proposed driving method adopts negative bias annealing to suppress the $V_{\sf {th}}$ shift. The annealing time is optimized based on the experimental observation of the minimum $V_{\sf {th}}$ shift. After a stress time of 30000 s, the measurement results show that the $V_{\sf {th}}$ shift is reduced by 29.6%, using an optimized annealing time of 5% of one frame time. In addition, the maximum deviation in the emission current using the proposed driving method was measured to be less than 4.32% after a stress time of 30000 s. Auteurs: Woo-Sul Shin;Hyun-A Ahn;Jun-Seok Na;Seong-Kwan Hong;Oh-Kyong Kwon;Ji-Hun Lee;Jae-Gwang Um;Jin Jang;Sung-Hwan Kim;Jeong-Soo Lee; Apparue dans: IEEE Electron Device Letters Date publication: 06.-2017, volume: 38, issue:6, pages: 760 - 762 Editeur: IEEE Document complet vers site de l'éditeur
» A Dual-Patch Polarization Rotation Reflective Surface and Its Application to Ultra-Wideband RCS Reduction
 Résumé:An ultra-wideband polarization rotation reflective surface (PRRS) with a high polarization conversion ratio (PCR) is proposed, which can reflect a linearly polarized incident wave with 90° polarization rotation. The unit cell of the proposed PRRS consists of a square and L-shaped patches printed on a substrate, which is covered by a superstrate and backed by a metallic ground. The two patches are connected to the ground using two metallic vias, respectively. Compared with the previously reported PRRS, the polarization rotation bandwidth of the proposed PRRS is enhanced from 49% to 97% with a high PCR of 96%. The frequency responses within the operation frequency band are consistent under oblique incident waves. Furthermore, the designed PRRS is applied to the ultra-wideband radar cross-section (RCS) reduction by forming a checkerboard surface. A 10-dB RCS reduction is achieved over an ultra-wideband of 98%. To validate the simulation results, a prototype of the checkerboard surface is fabricated and measured. A good agreement between the experimental and simulation results is obtained. Auteurs: Yongtao Jia;Ying Liu;Y. Jay Guo;Kun Li;Shuxi Gong; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 06.-2017, volume: 65, issue:6, pages: 3291 - 3295 Editeur: IEEE Document complet vers site de l'éditeur
» A Dynamic Approach for Workload Partitioning on GPU Architectures
» A Dynamic Zoom ADC With 109-dB DR for Audio Applications
 Résumé:This paper presents the first dynamic zoom ADC. Intended for audio applications, it achieves 109-dB DR, 106-dB signal-to-noise ratio, and 103-dB SNDR in a 20-kHz bandwidth, while dissipating only 1.12 mW. This translates into the state-of-the-art energy efficiency as expressed by a Schreier FoM of 181.5 dB. It also achieves the state-of-the-art area efficiency, occupying only 0.16 mm2 in the 0.16- $\mu \text{m}$ CMOS. These advances are enabled by the use of concurrent fine and coarse conversions, dynamic error-correction techniques, and a dynamically biased inverter-based operational transconductance amplifier. Auteurs: Burak Gönen;Fabio Sebastiano;Rui Quan;Robert van Veldhoven;Kofi A. A. Makinwa; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 06.-2017, volume: 52, issue:6, pages: 1542 - 1550 Editeur: IEEE Document complet vers site de l'éditeur
» A Fast Algorithm for Testability Analysis of Large Linear Time-Invariant Networks
 Résumé:Testability analysis is aimed at evaluating the degree of solvability of both the fault diagnosis and the parameter identification problems. As far as analog linear time-invariant circuits are concerned, various approaches, predicated on either fully numerical or symbolic techniques, have been proposed in the past for such purpose. However, the former are severely plagued by the effects of roundoff errors, whereas the latter soon become unacceptably time-consuming as the circuit size grows large. In the present paper, a novel algorithm is described, which completely avoids resorting to symbolic techniques, thereby overcoming the mentioned related drawbacks and, at the same time, it drastically reduces the computational issues posed by formerly proposed fully numerical methods. Such an algorithm provides information as to how many and which parameters can be diagnosed or identified and has been straightforwardly translated into a software for fully automated testability analysis, also briefly described herein. The aforementioned noteworthy features of the algorithm on which it is based render the software in question a successful tool for testability analysis of very large networks, as opposed to formerly proposed computer programs, which generally fail such a task. Examples of application of both the algorithm and its software counterpart are given. Auteurs: Giuseppe Fontana;Antonio Luchetta;Stefano Manetti;Maria Cristina Piccirilli; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 06.-2017, volume: 64, issue:6, pages: 1564 - 1575 Editeur: IEEE Document complet vers site de l'éditeur
» A Fast and Robust Beamspace Adaptive Beamformer for Medical Ultrasound Imaging
 Résumé:Minimum variance beamformer (MVB) increases the resolution and contrast of medical ultrasound imaging compared with nonadaptive beamformers. These advantages come at the expense of high computational complexity that prevents this adaptive beamformer to be applied in a real-time imaging system. A new beamspace (BS) based on discrete cosine transform is proposed in which the medical ultrasound signals can be represented with less dimensions compared with the standard BS. This is because of symmetric beampattern of the beams in the proposed BS compared with the asymmetric ones in the standard BS. This lets us decrease the dimensions of data to two, so a high complex algorithm, such as the MVB, can be applied faster in this BS. The results indicated that by keeping only two beams, the MVB in the proposed BS provides very similar resolution and also better contrast compared with the standard MVB (SMVB) with only 0.44% of needed flops. Also, this beamformer is more robust against sound speed estimation errors than the SMVB. Auteurs: Ali Mohades Deylami;Babak Mohammadzadeh Asl; Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Date publication: 06.-2017, volume: 64, issue:6, pages: 947 - 958 Editeur: IEEE Document complet vers site de l'éditeur
» A Fast Methodology for Topology Optimizations of Electromagnetic Devices
 Résumé:To alleviate the excessive computational burden involved in topology optimizations, an efficient methodology for topology optimization is proposed. In the proposed methodology, a multi-scale on/off method is designed to avoid using infinite number of decision parameters; and a stochastic approximation method is employed to minimize the computational costs when computing the sensitivity information. Numerical results are reported to showcase the merits of the proposed methodology. Auteurs: S. L. Ho;Shiyou Yang;Yanan Bai; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» A Fast Patches-Based Imaging Algorithm for 3-D Multistatic Imaging
 Résumé:Three-dimensional multistatic imaging is a powerful noninvasive examination tool for many military and civilian applications. Recently, the sparsity-regularized optimization has been used as a popular imaging technique to enhance the image quality. However, it suffers from the expensive computational cost, since its solution is obtained by a time-consuming iterative scheme, which is typically computationally prohibitive for large-scale imaging problems. To overcome this difficulty, this challenging imaging problem is converted into an image processing problem in this letter, which can be performed over small-scale overlapping patches and be efficiently solved in a parallel or distributed manner. In this way, the proposed qualitative scheme could be utilized to solve large-scale imaging problems. Exemplary simulation results are provided to demonstrate the efficiency of the proposed methodology. Auteurs: Long-Gang Wang;Lianlin Li;Jun Ding;Tie Jun Cui; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 06.-2017, volume: 14, issue:6, pages: 941 - 945 Editeur: IEEE Document complet vers site de l'éditeur
» A Five-Freedom Active Damping and Alignment Device Used in the Joule Balance
 Résumé:Damping devices are necessary for suppressing the undesired coil motions in the watt/joule balance. In this paper, an active electromagnetic damping device, located outside the main magnet, is introduced in the joule balance project. The presented damping device can be used in both dynamic and static measurement modes. With the feedback from a detection system, five degrees of freedom of the coil, i.e., the horizontal displacements $x$ and $y$ and the rotation angles $\theta _{x}$ , $\theta _{y}$ , and $\theta _{z}$ , can be controlled by the active damping device. Hence, two functions, i.e., suppressing the undesired coil motions and reducing the misalignment error, can be realized with this active damping device. The principle, construction, and performance of the proposed active damping device are presented. Auteurs: Jinxin Xu;Qiang You;Zhonghua Zhang;Zhengkun Li;Shisong Li; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 06.-2017, volume: 66, issue:6, pages: 1309 - 1316 Editeur: IEEE Document complet vers site de l'éditeur
» A Flexible Millimeter-Wave Channel Sounder With Absolute Timing
 Résumé:This paper presents a novel ultrawideband wireless spread spectrum millimeter-wave (mmWave) channel sounder that supports both a wideband sliding correlator mode and a real-time spread spectrum mode, also known as wideband correlation or direct correlation. Both channel sounder modes are capable of absolute propagation delay (time of flight) measurements with up to 1 GHz of radio frequency null-to-null bandwidth, and can measure multipath with a 2-ns time resolution. The sliding correlator configuration facilitates long-distance measurements with angular spread and delay spread for up to 185 dB of maximum measurable path loss. The real-time spread spectrum mode is shown to support short-range, small-scale temporal, and Doppler measurements (minimum snapshot sampling interval of $32.753~\mu \text{s}$ ) with a substantial dynamic fading range of 40 dB for human blockage and dynamic urban scenarios. The channel sounder uses field programmable gate arrays, analog-to-digital converters, digital-to-analog converters, and low-phase-noise rubidium standard references for frequency/time synchronization and absolute time delay measurements. Using propagation theory, several methods are presented here to calibrate and verify the accuracy of the channel sounder, and an improved diffraction model for human blockage, based on the METIS model but now including directional antenna gains, is developed from measurements using the channel sounder. The mmWave channel sounder described here may be used for accurate spatial and temporal ray-tracing calibration, to identify individual multipath components, to measure antenna patterns, for constructing spatial profiles of mmWave channels, and for developing statistical channel impulse response models in time and space. Auteurs: George R. MacCartney;Theodore S. Rappaport; Apparue dans: IEEE Journal on Selected Areas in Communications Date publication: 06.-2017, volume: 35, issue:6, pages: 1402 - 1418 Editeur: IEEE Document complet vers site de l'éditeur
» A Flexible Multi-Channel Coordination MAC Protocol for Vehicular Ad Hoc Networks
 Résumé:The IEEE 802.11p/1609.4 standard supports both safety applications and non-safety services for vehicular ad hoc networks (VANETs) via multi-channel operations. In this letter, we establish an analytical model to calculate the optimal bandwidth resource allocation and propose a flexible multi-channel coordination MAC (FMC-MAC) protocol for VANETs. The FMC-MAC protocol allows safety messages broadcasted on service channel and non-safety data transmitted on control channel in a flexible way. It does not only guarantee the reliability of safety applications, but also improve the throughput of non-safety services. The simulation results validate the analytical model and the proposed FMC-MAC protocol. Auteurs: Yuan Yao;Kailong Zhang;Xingshe Zhou; Apparue dans: IEEE Communications Letters Date publication: 06.-2017, volume: 21, issue:6, pages: 1305 - 1308 Editeur: IEEE Document complet vers site de l'éditeur
» A Forest Vitality and Change Monitoring Tool Based on RapidEye Imagery
 Résumé:Forest damage and health problems can be identified, mapped, and better managed through the analysis of satellite imagery. However, a high degree of efficiency is achieved only if a workflow for preprocessing and analysis is mature enough for production and can be deployed in an operational processing environment. This letter shows a path for turning research into an operational tool for the purposes of forest delineation and disturbance monitoring using high-resolution RapidEye satellite imagery. The implemented workflow follows a modularized approach with separate modules for image registration, radiometric normalization, classification, and bitemporal analysis. The tool was developed for commercial service provision. It has successfully been deployed for the fourth year for German state forest customers. It makes use of python and python libraries, as well as algorithms of PCI Geomatica. The letter concludes with a case study showing the defoliation monitoring results of a Scots pine plantation area affected by a nun moth outbreak. Auteurs: Alexander Marx;Gideon Okpoti Tetteh; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 06.-2017, volume: 14, issue:6, pages: 801 - 805 Editeur: IEEE Document complet vers site de l'éditeur
» A Framework for Integrating Content Characteristics into the Future Internet Architecture
 Résumé:Content characteristics such as content size can bring significant benefits for both network management and improving quality of experience. However, the current Internet architecture does not have a direct mechanism to know content characteristics. In this article, we argue that it is necessary to integrate content characteristics into the future Internet architecture. We present the design challenges, propose a framework for implementation, and build a prototype to demonstrate the feasibility of the proposed framework. To show the benefits of integrating content characteristics into the Internet architecture, we also present numerical results obtained from running experiments on the prototype by using real data traces. Auteurs: Hongbin Luo;Yakun Xu;Wanjun Xie;Zhe Chen;Jiawei Li;Hongke Zhang;Han-Chieh Chao; Apparue dans: IEEE Network Date publication: 06.-2017, volume: 31, issue:3, pages: 22 - 28 Editeur: IEEE Document complet vers site de l'éditeur
» A Fully Integrated Wireless SoC for Motor Function Recovery After Spinal Cord Injury
 Résumé:This paper presents a wirelessly powered, fully integrated system-on-a-chip (SoC) supporting 160-channel stimulation, 16-channel recording, and 48-channel bio-impedance characterization to enable partial motor function recovery through epidural spinal cord electrical stimulation. A wireless transceiver is designed to support quasi full-duplex data telemetry at a data rate of 2 Mb/s. Furthermore, a unique in situ bio-impedance characterization scheme based on time-domain analysis is implemented to derive the Randles cell electrode model of the electrode-electrolyte interface. The SoC supports concurrent stimulation and recording while the high-density stimulator array meets an output compliance voltage of up to ±10 V with versatile stimulus programmability. The SoC consumes 18 mW and occupies a chip area of 5.7 mm × 4.4 mm using 0.18 μm high-voltage CMOS process. In our in vivo rodent experiment, the SoC is used to perform wireless recording of EMG responses while stimulation is applied to enable the standing and stepping of a paralyzed rat. To facilitate the system integration, a novel thin film polymer packaging technique is developed to provide a heterogeneous integration of the SoC, coils, discrete components, and high-density flexible electrode array, resulting in a miniaturized prototype implant with a weight and form factor of 0.7 g and 0.5 cm3, respectively. Auteurs: Yi-Kai Lo;Yen-Cheng Kuan;Stanislav Culaclii;Brian Kim;Po-Min Wang;Chih-Wei Chang;Jonathan A. Massachi;Minji Zhu;Kuanfu Chen;Parag Gad;V. Reggie Edgerton;Wentai Liu; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 06.-2017, volume: 11, issue:3, pages: 497 - 509 Editeur: IEEE Document complet vers site de l'éditeur
» A Fuzzy Group Decision Making Model for Ordinal Peer Assessment
 Résumé:Massive Open Online Courses (MOOCs) are becoming an increasingly popular choice for education but, to reach their full extent, they require the resolution of new issues like assessing students at scale. A feasible approach to tackle this problem is peer assessment, in which students also play the role of assessor for assignments submitted by others. Unfortunately, students are unreliable graders so peer assessment often does not deliver accurate results. In order to mitigate this issue, we propose a new model for ordinal peer assessment based on the principles of fuzzy group decision making. In our approach, each student is asked to rank a few random submissions from the best to the worst and to specify, with a set of intuitive labels, at what extent each submission is better than the following one in the ranking. Students’ provided rankings are then transformed in fuzzy preference relations, expanded to estimate missing values and aggregated through OWA operators. The aggregated relation is then used to generate a global ranking between the submissions and to estimate their absolute grades. Experimental results are presented and show better performances with respect to other existing ordinal and cardinal peer assessment techniques both in the reconstruction of the correct ranking and on the estimation of students’ grades. Auteurs: Nicola Capuano;Vincenzo Loia;Francesco Orciuoli; Apparue dans: IEEE Transactions on Learning Technologies Date publication: 06.-2017, volume: 10, issue:2, pages: 247 - 259 Editeur: IEEE Document complet vers site de l'éditeur
» A Gain Equalizer Based on Dual-Mode Circular Substrate Integrated Waveguide Resonators
 Résumé:A microwave gain equalizer (GE) with good tunability, high Q factor, and compact volume for Ku-band application based on dual-mode circular substrate integrated waveguide (SIW) resonators is proposed. The characteristics of two orthogonal coupled slots to excite the dual modes are presented, and the optimal position of thin-film resistor to tune attenuation has been investigated. The resonant frequencies and attenuations of the dual-mode can be tuned independently, and the GE is easily fit to a required attenuation curve. For demonstration, the GE is designed and fabricated, and measured results agree well with simulated ones. Auteurs: Dewei Zhang;Qing Liu;Dongfang Zhou;Shuxing Wang;Yi Zhang; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 06.-2017, volume: 27, issue:6, pages: 539 - 541 Editeur: IEEE Document complet vers site de l'éditeur
» A Game Theoretic Approach to Real-Time Robust Distributed Generation Dispatch
 Résumé:Power demands are rising at an exponential pace due to the increasing proliferation of high-energy consuming devices such as plug-in hybrid electric vehicles. It is well known that scaling traditional power generation systems to accommodate these soaring demands will be excessively costly and may lead to negative environmental ramifications. One approach to supplement increasing energy needs involves diversifying the generation mix to incorporate a large number of local distributed generators (DGs) for economical and sustainable operation. However, such an approach remains an open challenge due to the inherent generation variability of DGs. In this paper, we propose a distributed generation dispatch strategy that can effectively coordinate a large number of DGs to meet consumer demand in real time. Through theoretical analysis based on population games and simulation studies, we demonstrate that our dispatch strategy is scalable and allows for the seamless integration of alternative energy resources into the grid in a robust and an optimally cost-effective manner. Auteurs: Pirathayini Srikantha;Deepa Kundur; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 06.-2017, volume: 13, issue:3, pages: 1006 - 1016 Editeur: IEEE Document complet vers site de l'éditeur
» A General Framework for Synchronizing a Team of Robots Under Communication Constraints
 Résumé:This paper addresses a synchronization problem that arises when a team of robots needs to communicate while repeatedly performing assigned tasks in a cooperative scenario. Each robot has a limited communication range and moves along a previously defined closed trajectory. When two robots are close enough, a communication link may be established, allowing the robots to exchange information. The goal is to schedule the motions such that the entire system can be synchronized for maximum information exchange; that is, every pair of neighbors always visit the feasible communication link at the same time. An algorithm for scheduling the team of robots in this scenario is proposed and a robust framework that assures the synchronization of a large team of robots is presented. Simulations, experiments, and computational results demonstrate the applicability of the algorithm. The approach allows the design of fault-tolerant systems that can be used for multiple tasks, such as surveillance, area exploration, and searching for targets in hazardous environments, among others. Auteurs: Jose-Miguel Díaz-Báñez;Luis Evaristo Caraballo;Mario Alberto Lopez;Sergey Bereg;Ivan Maza;Anibal Ollero; Apparue dans: IEEE Transactions on Robotics Date publication: 06.-2017, volume: 33, issue:3, pages: 748 - 755 Editeur: IEEE Document complet vers site de l'éditeur
» A General Solution for Iso-Disparity Layers and Correspondence Field Model for Stereo Systems
 Résumé:Estimation of localization error and selection of system parameters are the key factors in evaluation of visual 3-D systems. Iso-disparity layers and correspondence field are recently introduced to present a graphical model for space sampling in general 3-D systems. The correspondence field describes the spatial topology of the intersecting rays of cameras, arranged in a number of layers or surfaces with same disparity values, referred as iso-disparity layers. This paper develops a mathematical framework to investigate the geometrical variations of these layers with respect to camera intrinsic and extrinsic parameters. It will be demonstrated that the layers in their general form appear as a set of quadric surfaces, where the coefficients of these quadrics depend on system parameters. The distance between the iso-disparity layers due to the quantization process is suggested as a measure of uncertainty and can be considered as a criterion for appropriate selection of parameters, such as focal length, position, and orientation of cameras for the system to achieve desirable precision. Here, we use an analytical solution to calculate the orthogonal distance between the two successive iso-disparity layers. These distances are representatives of depth uncertainty. Finally, we have simulated our model and the results verify that the total average error is less than 2%. Auteurs: Mazaher Karami;Amir Mousavinia;Mehdi Ehsanian; Apparue dans: IEEE Sensors Journal Date publication: 06.-2017, volume: 17, issue:12, pages: 3744 - 3753 Editeur: IEEE Document complet vers site de l'éditeur
» A General T-Stub Circuit for Decoupling of Two Dual-Band Antennas
 Résumé:This paper presents a novel technique for decoupling of two closely spaced dual-band antennas using T-stub circuits. A decoupling circuit consists of three T-stub elements, each of which provides the required phases and impedances in dual frequency bands independently. A set of general design formulas is derived for determining the electric parameters of required T-stubs. To validate the new decoupling technique, a pair of dual-band inverted-F antennas working in the 2.45- and 5.8-GHz bands and another pair of dual-band monopole antennas working in the 2.4- and 5.2-GHz bands with and without the decoupling circuit are designed, prototyped, and measured. The measured S-parameters correlate with the theoretical designed data very well. With the decoupling circuit, significant improvement in antenna efficiency and data throughput demonstrates that the technique is useful for wireless terminals, where dual-band multiple-input and multiple-output antennas are used. Auteurs: Jiangwei Sui;Ke-Li Wu; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 06.-2017, volume: 65, issue:6, pages: 2111 - 2121 Editeur: IEEE Document complet vers site de l'éditeur
» A Generalized Framework for Inference-Based Diagnosis of Discrete Event Systems Capturing Both Disjunctive and Conjunctive Decision-Making
 Résumé:We have previously introduced an inference-based framework for decentralized decision-making, comprising of multiple observers, each with its own partial observation, where inferencing over the ambiguities of the self and the others is used to issue local decisions, and a global decision is taken to be the one possessing the minimum ambiguity level. In this setting, we previously introduced the notion of $N$ -inference $\vee$ -diagnosability to characterize the existence of a disjunctive decentralized diagnosis scheme so that any fault can be detected within a bounded delay, using at most $N$ -levels of inferencing, by one of the diagnosers. While the disjunctive scheme relies on one of the diagnosers making the failure decision, the dual conjunctive scheme relies on none of the diagnosers making the nonfailure decision. It is known that the two schemes are incomparable, and in this paper we extend our earlier work to provide a more general framework, introducing the notion of $N$ -inference diagnosability, capturing both disjunctive and conjunctive schemes. We also develop a method for verifying $N$-inference diagnosability, as well as discuss several of its useful properties. Auteurs: Shigemasa Takai;Ratnesh Kumar; Apparue dans: IEEE Transactions on Automatic Control Date publication: 06.-2017, volume: 62, issue:6, pages: 2778 - 2793 Editeur: IEEE Document complet vers site de l'éditeur
» A Generalized Zero-Forcing Precoder With Successive Dirty-Paper Coding in MISO Broadcast Channels
 Résumé:In this paper, we consider precoder designs for multiuser multiple-input-single-output broadcasting channels. Instead of using a traditional linear zero-forcing (ZF) precoder, we propose a generalized ZF (GZF) precoder in conjunction with successive dirty-paper coding (DPC) for data transmissions, namely, the GZF-DP precoder, where the suffix “DP” stands for “dirty-paper.” The GZF-DP precoder is designed to generate a band-shaped and lower triangular effective channel ${F}$ , such that only the entries along the main diagonal and the $\nu$ first lower-diagonals can take non-zero values. Utilizing the successive DPC, the known non-causal inter-user interferences from the other (up to) $\nu$ users are canceled through successive encoding. We analyze optimal GZF-DP precoder designs both for sum-rate and minimum user-rate maximizations. Utilizing Lagrange multipliers, the optimal precoders for both cases are solved in closed-forms in relation to optimal power allocations. For the sum-rate maximization, the optimal power allocation can be found through water filling, but with modified water levels depending on the parameter $\nu$ , while for the minimum user-rate maximization that measures the quality of the service, the optimal power allocation is directly solved in closed-form, which also depends on $\nu$ . Moreover, we propose two low-complexity user-ordering algorithms for the GZF-DP precoder designs for both maximizations, respectively. We show, through numerical results, that the proposed GZF-DP precoder with a small $\nu$ value (≤ 3) renders significant rate increments compared with the previous precoder designs, such as the linear ZF and the user-grouping-based DPC precoders. Auteurs: Sha Hu;Fredrik Rusek; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 06.-2017, volume: 16, issue:6, pages: 3632 - 3645 Editeur: IEEE Document complet vers site de l'éditeur
» A Generic Framework for Modeling MAC Protocols in Wireless Sensor Networks
 Résumé:Wireless sensor networks are employed in many applications, such as health care, environmental sensing, and industrial monitoring. An important research issue is the design of efficient medium access control (MAC) protocols, which have an essential role for the reliability, latency, throughput, and energy efficiency of communication, especially as communication is typically one of the most energy consuming tasks. Therefore, analytical models providing a clear understanding of the fundamental limitations of the different MAC schemes, as well as convenient way to investigate their performance and optimize their parameters, are required. In this paper, we propose a generic framework for modeling MAC protocols, which focuses on energy consumption, latency, and reliability. The framework is based on absorbing Markov chains, and can be used to compare different schemes and evaluate new approaches. The different steps required to model a specific MAC using the proposed framework are illustrated through a study case. Moreover, to exemplify how the proposed framework can be used to evaluate new MAC paradigms, evaluation of the novel pure-asynchronous approach, enabled by emerging ultra-low-power wake-up receivers, is done using the proposed framework. Experimental measurements on real hardware were performed to set framework parameters with accurate energy consumption and latency values, to validate the framework, and to support our results. Auteurs: Fayçal Ait Aoudia;Matthieu Gautier;Michele Magno;Olivier Berder;Luca Benini; Apparue dans: IEEE/ACM Transactions on Networking Date publication: 06.-2017, volume: 25, issue:3, pages: 1489 - 1500 Editeur: IEEE Document complet vers site de l'éditeur
» A Geometric Frequency-Domain Wave Propagation Formulation for Fast Convergence of Iterative Solvers
 Résumé:The frequency-domain wave propagation problem is notoriously difficult to solve through iterative methods because it leads to a symmetric but indefinite linear system. For this reason, direct methods are usually employed at the expense of great memory usage. Convergence of iterative methods, however, could be obtained by regularizing the wave equation. We introduce such regularization in discrete geometric approach framework on polyhedral grids. Moreover, we extend the regularization to the impedance boundary condition. Auteurs: Matteo Cicuttin;Lorenzo Codecasa;Ruben Specogna;Francesco Trevisan; Apparue dans: IEEE Transactions on Magnetics Date publication: 06.-2017, volume: 53, issue:6, pages: 1 - 4 Editeur: IEEE Document complet vers site de l'éditeur
» A Heterogeneous Network Based Method for Identifying GBM-Related Genes by Integrating Multi-Dimensional Data
 Résumé:The emergence of multi-dimensional data offers opportunities for more comprehensive analysis of the molecular characteristics of human diseases and therefore improving diagnosis, treatment, and prevention. In this study, we proposed a heterogeneous network based method by integrating multi-dimensional data (HNMD) to identify GBM-related genes. The novelty of the method lies in that the multi-dimensional data of GBM from TCGA dataset that provide comprehensive information of genes, are combined with protein-protein interactions to construct a weighted heterogeneous network, which reflects both the general and disease-specific relationships between genes. In addition, a propagation algorithm with resistance is introduced to precisely score and rank GBM-related genes. The results of comprehensive performance evaluation show that the proposed method significantly outperforms the network based methods with single-dimensional data and other existing approaches. Subsequent analysis of the top ranked genes suggests they may be functionally implicated in GBM, which further corroborates the superiority of the proposed method. The source code and the results of HNMD can be downloaded from the following URL: http://bioinformatics.ustc.edu.cn/hnmd/ . Auteurs: Chen Peng;Ao Li; Apparue dans: IEEE/ACM Transactions on Computational Biology and Bioinformatics Date publication: 06.-2017, volume: 14, issue:3, pages: 713 - 720 Editeur: IEEE Document complet vers site de l'éditeur
» A High Performance Block Eigensolver for Nuclear Configuration Interaction Calculations
 Résumé:As on-node parallelism increases and the performance gap between the processor and the memory system widens, achieving high performance in large-scale scientific applications requires an architecture-aware design of algorithms and solvers. We focus on the eigenvalue problem arising in nuclear Configuration Interaction (CI) calculations, where a few extreme eigenpairs of a sparse symmetric matrix are needed. We consider a block iterative eigensolver whose main computational kernels are the multiplication of a sparse matrix with multiple vectors (SpMM), and tall-skinny matrix operations. We present techniques to significantly improve the SpMM and the transpose operation SpMM $^T$ by using the compressed sparse blocks (CSB) format. We achieve 3-4 $\times$ speedup on the requisite operations over good implementations with the commonly used compressed sparse row (CSR) format. We develop a performance model that allows us to correctly estimate the performance of our SpMM kernel implementations, and we identify cache bandwidth as a potential performance bottleneck beyond DRAM. We also analyze and optimize the performance of LOBPCG kernels (inner product and linear combinations on multiple vectors) and show up to 15$\times$ speedup over using high performance BLAS libraries for these operations. The resulting high performance LOBPCG solver achieves 1.4 $\times$ to 1.8 $\times$ speedup over the existing Lanczos solver on a series of CI computations on high-end multicore architectures (Intel Xeons). We also analyze the performance of our techniques on an Intel Xeon Phi Knights Corner (KNC) processor. Auteurs: Hasan Metin Aktulga;Md. Afibuzzaman;Samuel Williams;Aydın Buluç;Meiyue Shao;Chao Yang;Esmond G. Ng;Pieter Maris;James P. Vary; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 06.-2017, volume: 28, issue:6, pages: 1550 - 1563 Editeur: IEEE Document complet vers site de l'éditeur
» A High Performance Distributed Optical Fiber Sensor Based on Φ-OTDR for Dynamic Strain Measurement
 Résumé:A high-performance distributed optical fiber sensor based on phase-sensitive optical time-domain reflectometry (Φ-OTDR) for dynamic strain measurement has been proposed. In this newly designed system, ultraweak fiber Bragg gratings (UWFBGs) are sparsely embedded in the sensing fiber. Through an unbalanced 3 × 3 coupler structure, the reflected lights from two adjacent UWFBGs would be mixed with each other and then split into three parts for phase demodulation. Then, a novelty table-look-up scheme is introduced to precisely demodulate the frequency, amplitude, and phase of dynamic strain. Rayleigh back-scattering light is utilized to identify and locate the accurate position of vibration event between two adjacent UWFBGs. The experimental results show that the proposed system is capable of reconstructing the vibration with a linear intensity response of R2 = 0.9986 and a fiber length variation sensitivity of 117 pm/(Hz)1/2. Meanwhile, a wide frequency response band from 50 to 2075 Hz is achieved with high signal-to-noise ratio above 56 dB. Auteurs: Xuping Zhang;Zhenhong Sun;Yuanyuan Shan;Yanting Li;Feng Wang;Jie Zeng;Yixin Zhang; Apparue dans: IEEE Photonics Journal Date publication: 06.-2017, volume: 9, issue:3, pages: 1 - 12 Editeur: IEEE Document complet vers site de l'éditeur
» A High Point for Nation's First Women in Engineering High School Program: Celebrating 15 years of WIE [Pipelining: Attractive Programs for Women]
 Résumé:In 2002, in the northernmost tip of rural New Jersey, at High Point Regional High School, Mark Wallace, the supervisor of Instructional Technology created the first Women In Engineering (WIE) high school program. It has lasted to this day. Auteurs: Debbie Sniderman; Apparue dans: IEEE Women in Engineering Magazine Date publication: 06.-2017, volume: 11, issue:1, pages: 33 - 35 Editeur: IEEE Document complet vers site de l'éditeur

Publication archives by date
2017:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2016:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2015:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2014:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2013:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2012:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2011:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2010:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre
2009:   janvier     février     mars     avril     mai     juin     juillet     août     septembre     octobre     novembre     décembre