###### Accueil » Publications dans le domaines des technologies » 10-2017
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 Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 10-2017 trié par par titre, page: 0
» $\gamma$ -Ray Detection Using Commercial Off-the-Shelf CMOS and CCD Image Sensors
 Résumé:In this paper, we present the results of research on the response of four types of commercial off-the-shelf (COTS), CMOS, and charge-coupled device (CCD) image sensors to $\gamma$ photons. The aim of this paper was to study the potential use of CCD and CMOS COTS image sensors as $\gamma$ -ray detectors. A 60Co $\gamma$ source was used to study the response behavior of the sensors to the irradiant photons. The results show that the CMOS image sensors have much less background noise before irradiation and have better radiation resistance below 51.24 Gy. The background noise of CCD sensors obviously increases with a larger total ionizing dose. The linearity of the dose-rate response of CCD COTS sensors is better than that of CMOS COTS sensors. Both mean pixel value and cumulative pixel value may be used to obtain the photon dose rate. The sensor technology structure difference leads to the different shapes of events. The Compton scattering of 60Co $\gamma$ photons in silicon caused the recorded patterns to show not only dots but also small streaks or traces. The peak value provides the photon energy, while the peak shape and radius can be used to classify the particle. CMOS COTS sensors are suitable for the particle classification, while CCD COTS sensors are better for energy resolution. Auteurs: Xu Shoulong;Zou Shuliang;Huang Youjun; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6599 - 6604 Editeur: IEEE Document complet vers site de l'éditeur
» $\gamma$ -Ray Detection Using Commercial Off-the-Shelf CMOS and CCD Image Sensors
 Résumé:In this paper, we present the results of research on the response of four types of commercial off-the-shelf (COTS), CMOS, and charge-coupled device (CCD) image sensors to $\gamma$ photons. The aim of this paper was to study the potential use of CCD and CMOS COTS image sensors as $\gamma$ -ray detectors. A 60Co $\gamma$ source was used to study the response behavior of the sensors to the irradiant photons. The results show that the CMOS image sensors have much less background noise before irradiation and have better radiation resistance below 51.24 Gy. The background noise of CCD sensors obviously increases with a larger total ionizing dose. The linearity of the dose-rate response of CCD COTS sensors is better than that of CMOS COTS sensors. Both mean pixel value and cumulative pixel value may be used to obtain the photon dose rate. The sensor technology structure difference leads to the different shapes of events. The Compton scattering of 60Co $\gamma$ photons in silicon caused the recorded patterns to show not only dots but also small streaks or traces. The peak value provides the photon energy, while the peak shape and radius can be used to classify the particle. CMOS COTS sensors are suitable for the particle classification, while CCD COTS sensors are better for energy resolution. Auteurs: Xu Shoulong;Zou Shuliang;Huang Youjun; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6599 - 6604 Editeur: IEEE Document complet vers site de l'éditeur
» $\gamma$ -Ray Detection Using Commercial Off-the-Shelf CMOS and CCD Image Sensors
 Résumé:In this paper, we present the results of research on the response of four types of commercial off-the-shelf (COTS), CMOS, and charge-coupled device (CCD) image sensors to $\gamma$ photons. The aim of this paper was to study the potential use of CCD and CMOS COTS image sensors as $\gamma$ -ray detectors. A 60Co $\gamma$ source was used to study the response behavior of the sensors to the irradiant photons. The results show that the CMOS image sensors have much less background noise before irradiation and have better radiation resistance below 51.24 Gy. The background noise of CCD sensors obviously increases with a larger total ionizing dose. The linearity of the dose-rate response of CCD COTS sensors is better than that of CMOS COTS sensors. Both mean pixel value and cumulative pixel value may be used to obtain the photon dose rate. The sensor technology structure difference leads to the different shapes of events. The Compton scattering of 60Co $\gamma$ photons in silicon caused the recorded patterns to show not only dots but also small streaks or traces. The peak value provides the photon energy, while the peak shape and radius can be used to classify the particle. CMOS COTS sensors are suitable for the particle classification, while CCD COTS sensors are better for energy resolution. Auteurs: Xu Shoulong;Zou Shuliang;Huang Youjun; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6599 - 6604 Editeur: IEEE Document complet vers site de l'éditeur
» ${k}$ -Sparse Autoencoder-Based Automatic Modulation Classification With Low Complexity
 Résumé:How to reduce complexity of the practical automatic modulation classification systems is a very active research area. Moreover, keeping the classification accuracy to a near optimal level is an added challenge. Recently, three new classifiers have been proposed with reduced complexity, mainly: linear support vector machine classifier, approximate maximum likelihood classifier, and backpropogation neural networks classifier. However, these methods include the sorting process of the features $z$ to form an ordered vector $\vec {z}$ employing $K$ log $(K)$ comparison operations. Here, we propose a ${k}$ -sparse autoencoder-based classifer, with unsorted input data features and called it unsorted deep neural network (UDNN). Thus, we strive to omit the $K$ log $(K)$ comparison operations. The results obtained using the UDNN classifier show improved performance when compared with the above three methods. Moreover, using ${k}$ highest hidden units to reconstruct input data further reduces the overall complexity of the AMC system. Auteurs: Afan Ali;Fan Yangyu; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2162 - 2165 Editeur: IEEE Document complet vers site de l'éditeur
» Δ-Source Impedance Network
 Résumé:Impedance networks have been already investigated in various literature with the main goals of increasing the attainable voltage gain and reducing the components number. Recently, coupled inductors found popularity because they let converters with lower weight and cost. It seems that coupled inductances are a proper answer to the increasing voltage gain while keeping down the components number. This paper proposes a novel impedance network circuit based on three coupled inductors with a Δ connection. The proposed Δ-source converter offers smaller magnetizing current and winding losses compared to the successful Y-source circuit. Moreover, with the Δ-connected three coupled inductors, the adverse effect of leakage inductance on the converter performance is significantly reduced. The effectiveness of the proposed structure is analytically proved. The theoretical achievements over the conventional Y-source structure are confirmed through extensive simulations and experiments. Auteurs: Amir Hakemi;Majid Sanatkar-Chayjani;Mohammad Monfared; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7842 - 7851 Editeur: IEEE Document complet vers site de l'éditeur
» 1- $\mu \text{m}$ Short-Channel Oxide Thin-Film Transistors With Triangular Gate Spacer
 Résumé:In this letter, high-performance back-channel etch type oxide thin-film transistors (TFTs) with very narrow channel length, $1~\mu \text{m}$ , are presented. To cover the steep slope at the dry-etched gate pattern edge with a thin gate insulator, a triangular-shaped gate spacer was introduced. A 1- $\mu \text{m}$ short-channel oxide TFT is particularly adaptable to next-generation display applications requiring very high resolution. The field-effect mobility ( $\mu _{\mathrm{ FE}})$ , subthreshold slope, turn-on voltage ( $\text{V}_{on})$ , and the on/off ratio were 55.2 cm2/Vs, 0.11 V/decade, 0.13 V, and $6.8\times 10^{9}$ , respectively. Auteurs: Ji Hun Choi;Jong-Heon Yang;Jae-Eun Pi;Chi-Young Hwang;Kyunghee Choi;Hee-Ok Kim;Oh-Sang Kwon;Chi-Sun Hwang; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1398 - 1400 Editeur: IEEE Document complet vers site de l'éditeur
» 1- $\mu \text{m}$ Short-Channel Oxide Thin-Film Transistors With Triangular Gate Spacer
 Résumé:In this letter, high-performance back-channel etch type oxide thin-film transistors (TFTs) with very narrow channel length, $1~\mu \text{m}$ , are presented. To cover the steep slope at the dry-etched gate pattern edge with a thin gate insulator, a triangular-shaped gate spacer was introduced. A 1- $\mu \text{m}$ short-channel oxide TFT is particularly adaptable to next-generation display applications requiring very high resolution. The field-effect mobility ( $\mu _{\mathrm{ FE}})$ , subthreshold slope, turn-on voltage ( $\text{V}_{on})$ , and the on/off ratio were 55.2 cm2/Vs, 0.11 V/decade, 0.13 V, and $6.8\times 10^{9}$ , respectively. Auteurs: Ji Hun Choi;Jong-Heon Yang;Jae-Eun Pi;Chi-Young Hwang;Kyunghee Choi;Hee-Ok Kim;Oh-Sang Kwon;Chi-Sun Hwang; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1398 - 1400 Editeur: IEEE Document complet vers site de l'éditeur
» 1- $\mu \text{m}$ Short-Channel Oxide Thin-Film Transistors With Triangular Gate Spacer
 Résumé:In this letter, high-performance back-channel etch type oxide thin-film transistors (TFTs) with very narrow channel length, $1~\mu \text{m}$ , are presented. To cover the steep slope at the dry-etched gate pattern edge with a thin gate insulator, a triangular-shaped gate spacer was introduced. A 1- $\mu \text{m}$ short-channel oxide TFT is particularly adaptable to next-generation display applications requiring very high resolution. The field-effect mobility ( $\mu _{\mathrm{ FE}})$ , subthreshold slope, turn-on voltage ( $\text{V}_{on})$ , and the on/off ratio were 55.2 cm2/Vs, 0.11 V/decade, 0.13 V, and $6.8\times 10^{9}$ , respectively. Auteurs: Ji Hun Choi;Jong-Heon Yang;Jae-Eun Pi;Chi-Young Hwang;Kyunghee Choi;Hee-Ok Kim;Oh-Sang Kwon;Chi-Sun Hwang; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1398 - 1400 Editeur: IEEE Document complet vers site de l'éditeur
» 1- $\mu \text{m}$ Short-Channel Oxide Thin-Film Transistors With Triangular Gate Spacer
 Résumé:In this letter, high-performance back-channel etch type oxide thin-film transistors (TFTs) with very narrow channel length, $1~\mu \text{m}$ , are presented. To cover the steep slope at the dry-etched gate pattern edge with a thin gate insulator, a triangular-shaped gate spacer was introduced. A 1- $\mu \text{m}$ short-channel oxide TFT is particularly adaptable to next-generation display applications requiring very high resolution. The field-effect mobility ( $\mu _{\mathrm{ FE}})$ , subthreshold slope, turn-on voltage ( $\text{V}_{on})$ , and the on/off ratio were 55.2 cm2/Vs, 0.11 V/decade, 0.13 V, and $6.8\times 10^{9}$ , respectively. Auteurs: Ji Hun Choi;Jong-Heon Yang;Jae-Eun Pi;Chi-Young Hwang;Kyunghee Choi;Hee-Ok Kim;Oh-Sang Kwon;Chi-Sun Hwang; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1398 - 1400 Editeur: IEEE Document complet vers site de l'éditeur
» 11th?IEEE UAE Student Day Hosted by Al Ain University [Around the Globe]
 Résumé:Presents information on the 11th IEEE UAE Student Day. Auteurs: Nazih Khaddaj Mallat; Apparue dans: IEEE Microwave Magazine Date publication: 10.-2017, volume: 18, issue:6, pages: 137 - 138 Editeur: IEEE Document complet vers site de l'éditeur
» 16th IEEE International Conference on Mathematical Methods in Electromagnetic Theory Held in Lviv, Ukraine [Meeting Reports]
 Résumé:Presents information on the 16th IEEE International Conference on Mathematical Methods in Electromagnetic Theory. Auteurs: Stephen P. Shipman; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 10.-2017, volume: 59, issue:5, pages: 18 - 20 Editeur: IEEE Document complet vers site de l'éditeur
» 16th Mediterranean Microwave Symposium Hosted by Al Ain University [Conference Report]
 Résumé:Presents information on the 16th Mediterranean Microwave Symposium. Auteurs: Nazih Khaddaj Mallat; Apparue dans: IEEE Microwave Magazine Date publication: 10.-2017, volume: 18, issue:6, pages: 132 - 134 Editeur: IEEE Document complet vers site de l'éditeur
» 2-D Magnetic Properties Measurement System for Electrical Steel Sheets Considering Laminated Direction Mechanical Stress
 Résumé:The 2-D rotating magnetic field is demonstrated in electrical steel sheets, which are widely used in iron cores of motors, etc. In addition, the magnetic properties of a motor iron core are strongly affected by the compressive stress in the laminated direction induced by welding, bolt bundles, etc. In order to investigate the rotating magnetic properties of the material under laminated direction stress, a novel magnetic properties measurement system is developed in this paper. The compressive stress is loaded on cubic specimen in the laminated direction. A novel sensing structure with combined magnetic flux density $B$ and magnetic field strength ${H}$ sensing coils is developed with an assistance of a four-layer printed circuit board. Such structure yields more accurate ${B}$ and ${H}$ measurement. The accuracy of magnetic properties measurement of the apparatus is validated by finite-element analysis. Except for investigating the correlation between the compressive stress and its magnetic properties of the electrical steel sheets, the coupling relationship between the magnetic property in ${x}$ -axis direction and the counterpart in ${y}$ -axis direction is found in 2-D rotational magnetization. Furthermore, the impact of the compressive stress on the coupling relationship is explored. The experimental results are reported, and the mechanism analysis is employed to discuss the results. Auteurs: Xiaofeng Ding;Suping Ren;Yanwen Xiong;Feida Chen;Jinquan Xu; Apparue dans: IEEE Transactions on Magnetics Date publication: 10.-2017, volume: 53, issue:10, pages: 1 - 11 Editeur: IEEE Document complet vers site de l'éditeur
» 2.4-GHz Absorptive MMIC Switch for Switched Beamformer Application
 Résumé:In this paper, a GaAs absorptive single-pole double-throw (SPDT) RF switch and its application to a 2.4-GHz switched beamformer module are presented. The proposed absorptive SPDT RF switch features low-power consumption and low insertion loss with good output matching both in the on and off states. Specifically, the measured insertion loss in the on state is less than 1 dB, and the measured input and output return losses are both better than 11.2 dB from 1.9 to 2.6 GHz. The measured output return loss in the off state is better than 15 dB, and the measured isolation is better than 24.7 dB in the same frequency range. Two proposed absorptive SPDT switches are then employed to form an absorptive single-pole four-throw RF switch, and it is integrated with a miniaturized $4 \times 4$ Butler matrix using the integrated passive device (IPD) technology to achieve a compact 2.4-GHz switched beamformer module with a very low profile. Specifically, the module size is 4.9 mm $\times5$ mm with a thickness of only 0.4 mm. The IPD beamformer module is then used to realize a low-profile 2-D scanning antenna array, and 16 different beams in azimuth and elevation dimensions are successfully generated. Auteurs: Wei-Ting Fang;Chia-Hao Chen;Yo-Shen Lin; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3950 - 3961 Editeur: IEEE Document complet vers site de l'éditeur
» 20 GHz Mode-Locked Laser Diodes With Integrated Optical Feedback Cavities in a Generic Monolithic InP Photonics Platform
 Résumé:We investigate integrated mode-locked laser diodes with distributed Bragg reflectors fabricated in the JePPIX-Oclaro indium phosphide photonics platform. The optical and radio-frequency (RF) characteristics of passively mode-locked lasers with and without monolithically integrated feedback cavities were measured and compared. The RF linewidth of the mode-locked laser could be reduced by integrating an optical feedback cavity of a particular length and a tunable magnitude of feedback. A maximum linewidth reduction factor of 1.9 was observed near the onset of mode locking, but increasing the laser optical power tended to lead to unstable operation. Increasing the drive current of the design without feedback also reduced the RF linewidth. A reduction factor of 7.6 was observed. Auteurs: Torrey Thiessen;Joyce K. S. Poon; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 10 Editeur: IEEE Document complet vers site de l'éditeur
» 2017 IEEE Antennas and Propagation Symposium Student Design Contest [Education Corner]
 Résumé:Presents information on the 2017 IEEE Antennas and Propagation Symposium Student Design Contest. Auteurs: Sean Victor Hum; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 10.-2017, volume: 59, issue:5, pages: 147 - 147 Editeur: IEEE Document complet vers site de l'éditeur
» 2017 IEEE International Workshop on Antenna Technology in Athens [Meeting Reports]
 Résumé:Presents information on 2017 IEEE International Workshop on Antenna Technology. Auteurs: Stavros Koulouridis; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 10.-2017, volume: 59, issue:5, pages: 21 - 23 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D In Vitro Acoustic Super-Resolution and Super-Resolved Velocity Mapping Using Microbubbles
 Résumé:Standard clinical ultrasound (US) imaging frequencies are unable to resolve microvascular structures due to the fundamental diffraction limit of US waves. Recent demonstrations of 2-D super-resolution both in vitro and in vivo have demonstrated that fine vascular structures can be visualized using acoustic single bubble localization. Visualization of more complex and disordered 3-D vasculature, such as that of a tumor, requires an acquisition strategy which can additionally localize bubbles in the elevational plane with high precision in order to generate super-resolution in all three dimensions. Furthermore, a particular challenge lies in the need to provide this level of visualization with minimal acquisition time. In this paper, we develop a fast, coherent US imaging tool for microbubble localization in 3-D using a pair of US transducers positioned at 90°. This allowed detection of point scatterer signals in 3-D with average precisions equal to $1.9~\mu \text{m}$ in axial and elevational planes, and $11~\mu \text{m}$ in the lateral plane, compared to the diffraction limited point spread function full-widths at half-maximum of 488, 1188, and $953~\mu \text{m}$ of the original imaging system with a single transducer. Visualization and velocity mapping of 3-D in vitro structures was demonstrated far beyond the diffraction limit. The capability to measure the complete flow pattern of blood vessels associated with disease at depth would ultimately enable analysis of in vivo microvascular morphology, blood flow dynamics, and occlusions resulting from disease states. Auteurs: Kirsten Christensen-Jeffries;Jemma Brown;Paul Aljabar;Mengxing Tang;Christopher Dunsby;Robert J. Eckersley; Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Date publication: 10.-2017, volume: 64, issue:10, pages: 1478 - 1486 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D Domain Decomposition Based Hybrid Finite-Difference Time-Domain/Finite-Element Time-Domain Method With Nonconformal Meshes
 Résumé:A new 3-D domain decomposition based hybrid finite-difference time-domain (FDTD)/finite-element time-domain (FETD) method is introduced to facilitate electromagnetic modeling by exploiting both the computational efficiency of FDTD and the meshing flexibility of FETD. The proposed hybrid method allows the FETD mesh and the FDTD grid to be nonconformal based on domain decomposition technique. It implements the hybridization with a buffer zone, which functions as a transition region between FDTD and FETD. The buffer zone helps the proposed hybrid method obviate the interpolation approach for field coupling of the nonconformal mesh and hence overcome the late-time instability issue. The discontinuous Galerkin method is utilized to couple different regions, thus improving the coupling accuracy compared with that using the Dirichlet boundary condition. Moreover, the hybrid method allows further division of the FETD region into multiple subdomains when the degrees of freedom in this region are large. For temporal discretization, a global leapfrog time integration scheme is implemented to sequentially update the fields in the FDTD, buffer, and FETD regions. The numerical results are shown to demonstrate the meshing flexibility and computational efficiency of the proposed hybrid method inherited from FETD and FDTD methods. Auteurs: Qingtao Sun;Qiang Ren;Qiwei Zhan;Qing Huo Liu; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3682 - 3688 Editeur: IEEE Document complet vers site de l'éditeur
» 3-inch GaN-on-Diamond HEMTs With Device-First Transfer Technology
 Résumé:Based on a device-first transfer process, a 3-inch polycrystalline diamond substrate is bonded within $1.5~\mu \text{m}$ of the junction in GaN high electron mobility transistors (HEMTs) to enhance heat removal of the high-power RF devices. Highly preserved electrical performance is demonstrated by comparison exactly on the same HEMT device prior and after substrate transfer. The residual compressive strain relaxation of the whole GaN epilayer does not reduce the 2-D electron gas sheet density. The dc characteristics show weakened self-heating in the GaN-on-diamond HEMT with maximum current density increasing from 968 to 1005 mA/mm. The power density increases from 4.8 to 5.5 W/mm with the PAE slightly reducing from 50.9% to 50.5%. On-wafer infrared measurement is performed on a 1.25-mm GaN HEMT at power dissipation of 10 W/mm, and the peak juncture temperature of the device decreases from 241 °C to 191 °C after transferring to the diamond substrate. Auteurs: Tingting Liu;Yuechan Kong;Lishu Wu;Huaixin Guo;Jianjun Zhou;Cen Kong;Tangsheng Chen; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1417 - 1420 Editeur: IEEE Document complet vers site de l'éditeur
» 4 $\times$ 10-Gb/s MIMO-Free Polarization and Mode Group Multiplexing for Data Center Applications
 Résumé:The $4\mathrm {\mathbf {\times }}10$ -Gb/s polarization- and mode group-multiplexed transmission without multiple-input–multiple-output equalization for data center applications is experimentally demonstrated, for the first time, over a 127-m panda-type polarization-maintaining few-mode fiber. A polarization crosstalk of less than −22.0 dB and a bending loss of <0.08 dB for one loop with a 5-mm radius were achieved. Auteurs: Wei Wang;Jian Zhao;Lin Zhang;Qi Mo;Zhiqun Yang;Chao Li;Zhen Wang;Zhenzhen Zhang;Christian Carboni;Guifang Li; Apparue dans: IEEE Photonics Technology Letters Date publication: 10.-2017, volume: 29, issue:20, pages: 1711 - 1714 Editeur: IEEE Document complet vers site de l'éditeur
» 4 $\times$ 10-Gb/s MIMO-Free Polarization and Mode Group Multiplexing for Data Center Applications
 Résumé:The $4\mathrm {\mathbf {\times }}10$ -Gb/s polarization- and mode group-multiplexed transmission without multiple-input–multiple-output equalization for data center applications is experimentally demonstrated, for the first time, over a 127-m panda-type polarization-maintaining few-mode fiber. A polarization crosstalk of less than −22.0 dB and a bending loss of <0.08 dB for one loop with a 5-mm radius were achieved. Auteurs: Wei Wang;Jian Zhao;Lin Zhang;Qi Mo;Zhiqun Yang;Chao Li;Zhen Wang;Zhenzhen Zhang;Christian Carboni;Guifang Li; Apparue dans: IEEE Photonics Technology Letters Date publication: 10.-2017, volume: 29, issue:20, pages: 1711 - 1714 Editeur: IEEE Document complet vers site de l'éditeur
» 4H–SiC Avalanche Photodiode Linear Array Operating in Geiger Mode
 Résumé:In this study, a 50-pixel linear array of 4H–SiC ultraviolet avalanche photodiodes operating in Geiger mode is reported for the first time. The 50 pixels within the linear array are all capable of detecting single photons but with a small number of them suffering from extra leakage current near avalanche breakdown. The enhanced leakage is likely correlated with structural defects existing within the epitaxial structure, which would lead to higher dark count rate (DCR) at the same single photon detection efficiency (SPDE) in Geiger mode. For a low-leakage avalanche photodiode device within the linear array, a room temperature SPDE of 15.4% at 280 nm is obtained with a corresponding DCR of 2.5 Hz/μm2. Auteurs: Lianghui Li;Dong Zhou;Hai Lu;Wenkai Liu;Xiaofan Mo;Fangfang Ren;Dunjun Chen;Ruiqi Wang;Guanglei Li;Rong Zhang;Youdou Zheng; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 7 Editeur: IEEE Document complet vers site de l'éditeur
» 4H-SiC MOSFETs With Borosilicate Glass Gate Dielectric and Antimony Counter-Doping
 Résumé:In this letter, it is demonstrated that 4H-SiC MOSFETs with borosilicate glass (BSG) as the gate dielectric result in significantly higher channel mobility than standard nitride oxide annealed devices, due to lower density of near-interfacial traps at the BSG/SiC interface. Using a thin Antimony-doped surface layer in conjunction with the BSG dielectric results in higher channel mobility at room temperature. The field-effect channel mobility of such devices is found to be 180 ${\rm {cm}}^{{2}}/{\text {V}}\cdot \text {s}$ at low transverse electric fields (close to threshold) and 94 ${\text {cm}}^{\text {2}}/{\text {V}}\cdot \text {s}$ at high fields (~2 MV/cm), which is about a factor of five higher than the state-of-the-art. This, along with a tunable threshold voltage, could make this approach very attractive for power MOSFET applications. However, the poor bias temperature instability of BSG is a big challenge for utilization of this dielectric. Auteurs: Yongju Zheng;T. Isaacs-Smith;A. C. Ahyi;S. Dhar; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1433 - 1436 Editeur: IEEE Document complet vers site de l'éditeur
» 500 °C High Current 4H-SiC Lateral BJTs for High-Temperature Integrated Circuits
 Résumé:High-current 4H-SiC lateral BJTs for high-temperature monolithic integrated circuits are fabricated. The BJTs have three different sizes and the designs are optimized in terms of emitter finger width and length and the device layout to have higher current density (JC), lower on-resistance (RON), and more uniform current distribution. A maximum current gain ( $\beta$ ) of >53 at significantly high current density was achieved for different sizes of SiC BJTs. The BJTs are measured from room temperature to 500 °C. An open-base breakdown voltage (VCEO) of >50 V is measured for the devices. Auteurs: Hossein Elahipanah;Saleh Kargarrazi;Arash Salemi;Mikael Östling;Carl-Mikael Zetterling; Apparue dans: IEEE Electron Device Letters Date publication: 10.-2017, volume: 38, issue:10, pages: 1429 - 1432 Editeur: IEEE Document complet vers site de l'éditeur
» 500 years of humanoid robots automata have been around longer than you think [Resources_Review]
 Résumé:When science fiction critics Eric S. Rabkin and Robert E. Scholes argued in the 1970s that "no one would go through the trouble of building and maintaining a robot to hand wash clothes or pick up the telephone receiver," they were apparently unaware that Japanese researchers had already made a long-term commitment to develop humanoid robots that could do exactly that. The goal was to care for the elderly in the 21st century. To this end, throughout the 1980s and 1990s, industrial giants Honda, Mitsubishi, and Toyota, as well as university research labs around the world, began demonstrating humanoid prototypes. More recently, the desire to operate in disaster sites like Fukushima has motivated even more researchers to explore humanoid designs. Auteurs: Lisa Nocks; Apparue dans: IEEE Spectrum Date publication: 10.-2017, volume: 54, issue:10, pages: 18 - 19 Editeur: IEEE Document complet vers site de l'éditeur
» 60-dB SNDR 100-MS/s SAR ADCs With Threshold Reconfigurable Reference Error Calibration
 Résumé:This paper presents a reference error calibration scheme for successive approximation register (SAR) analog-to-digital converters (ADCs) verified with two prototypes. Such a reference error often occurs in high-speed SAR ADCs due to the signal dependent fast switching transient, and leads to a large differential nonlinearity and missing codes, eventually degrading conversion accuracy. The calibration concept aims to differentiate the error outputs and correct them by simply performing a subtraction in the digital domain. It runs in the background with a little hardware overhead, and does not depend on the type of the input signal or reduce the dynamic range. Two prototypes were measured which are made up of different reference generation circuits. Design #1 has the reference voltage from off-chip and a 3-pF decoupling capacitor on-chip, while design #2 includes an on-chip reference buffer. Both designs were fabricated in 65-nm CMOS and achieve at least 9-dB improvement on signal-to-(Noise + Distortion) ratio (SNDR) after calibration. The total core area is around 0.012 mm2 for both chips and the Nyquist SNDR of designs #1 and #2 is 59.03 and 57.93 dB, respectively. Auteurs: Chi-Hang Chan;Yan Zhu;Cheng Li;Wai-Hong Zhang;Iok-Meng Ho;Lai Wei;Seng-Pan U;Rui Paulo Martins; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2576 - 2588 Editeur: IEEE Document complet vers site de l'éditeur
» 830-nm InGaAs Quantum Well Lasers With Very Low Beam Divergence
 Résumé:We report on our design and fabrication of 830-nm high-power semiconductor lasers with very low beam divergence. Here, we propose a novel approach in which by combining asymmetric waveguide and a feature called “pins” together, we were able to design an optimize epi structure, which not only produces a beam divergence of less than 16°, which is measured at the full width at the half maximum, but also has very good growth tolerance as well. Device test shows the beam divergence is as small as 13°, yet they still retain high slope efficiency of around 1.15 W/A and low threshold current of 400 mA for the devices with cavity length being 2 mm long, and ridge width being 40 μm wide. Auteurs: Bocang Qiu;Hai Martin Hu;Weimin Wang;James Ho;Wenbin Liu;Langxing Kuang;Taishan Wang;Shujuan Wu; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» DeAMON: A Decentralized Adaptive Multi-Hop Scheduling Protocol for 6TiSCH Wireless Networks
 Résumé:The IEEE 802.15.4-2015 standard provides a link-layer mechanism, based on time synchronized channel hopping (TSCH), to enable deterministic low-power wireless mesh networking. The emerging IPv6 over IEEE 802.15.4e TSCH (6TiSCH) working group aims at harmonizing an IP-enabled protocol stack with the IEEE 802.15.4e link layer. In 802.15.4-TSCH medium access control, nodes follow a communication schedule; however, the standard does not specify any scheduling policy. Therefore, a number of recent studies have investigated scheduling mechanisms for 6TiSCH wireless networks. This paper introduces DeAMON, which is decentralized adaptive multi-hop scheduling protocol for 6TiSCH wireless networks. The key features of DeAMON include traffic-awareness, sequential scheduling, parallel transmissions, robust over-provisioning, and adaptability to topology changes. Moreover, DeAMON incurs minimal signaling overhead. Performance evaluation demonstrates that DeAMON outperforms state-of-the-art distributed scheduling protocols in terms of reliability, latency, and resource utilization. Auteurs: Adnan Aijaz;Usman Raza; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6825 - 6836 Editeur: IEEE Document complet vers site de l'éditeur
» In Situ Test of Thickness and Sheet Resistance of Conductive Nanomaterial Using Microwave Cavity
 Résumé:Both thickness and sheet resistance of conductive nanomaterial deposited on glass substrate have been simultaneously measured using the TE011 mode cavity method. Measurements have been performed in two cavities with resonant frequency of ~10.8 and ~17.7 GHz, respectively. Measurement errors of thickness and sheet resistance can reach below 10%. Compared to existing methods, the presented method does not require prior knowledge on either film thickness or conductivity; what is more, by using the film as one of the end plates of the cavity, this method is noncontact and has little requirements on sample shape. These advantages suggest that the presented method has potential to be used in situ of monitoring the metal film characteristics such as that in microelectronic fabrication industry. Auteurs: Ming Ye;Lu Wang;Yongning He;Mojgan Daneshmand; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 942 - 944 Editeur: IEEE Document complet vers site de l'éditeur
» In Vivo Manipulation of Single Biological Cells With an Optical Tweezers-Based Manipulator and a Disturbance Compensation Controller
 Résumé:In vivo manipulation of biological cells has attracted considerable attention in recent years. This process is particularly useful for precision medicine, such as cancer target therapy. Robotics technology is becoming necessary to stably and effectively manipulate and control single target cells in a complex in vivo environment. This paper presents a robot-aided optical tweezers-based manipulation technology that serves a function in the transport of single biological cells in vivo. An enhanced disturbance compensation controller is developed to minimize the effect of fluids (e.g., blood flow) on the cell. The method has exhibited advantages of flexibility in adjusting cell tracking trajectory online and the capability to minimize steady-state error and eliminate overshoot. Simulations and experiments of tracking single target cells in living zebrafish embryos have demonstrated the effectiveness of the proposed approach in a dynamic in vivo environment. Auteurs: Xiaojian Li;Chichi Liu;Shuxun Chen;Yong Wang;Shuk Han Cheng;Dong Sun; Apparue dans: IEEE Transactions on Robotics Date publication: 10.-2017, volume: 33, issue:5, pages: 1200 - 1212 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.016 mm2 12 b $\Delta \Sigma$ SAR With 14 fJ/conv. for Ultra Low Power Biosensor Arrays
 Résumé:The instrumentation systems for implantable brain–machine interfaces represent one of the most demanding applications for ultra low-power analogue-to-digital-converters (ADC) to date. To address this challenge, this paper proposes a $\Delta \Sigma$ SAR topology for very large sensor arrays that allows an exceptional reduction in silicon footprint by using a continuous time 0–2MASH topology. This configuration uses a specialized FIR window to decimate the $\Delta \Sigma$ modulator output and reject mismatch errors from the SAR quantizer, which mitigates the overhead from dynamic element matching techniques commonly used to achieve high precision. A fully differential prototype was fabricated using $0.18\,\mu$ m CMOS to demonstrate 10.8 ENOB precision with a 0.016 mm2 silicon footprint. Moreover, a 14fJ/conv figure-of-merit can be achieved, while resolving signals with the maximum input amplitude of ±1.2 Vpp sampled at 200 kS/s. The ADC topology exhibits a number of promising characteristics for both high speed and ultra low-power systems due to the reduced complexity, switching noise, sampling load, and oversampling ratio, which are critical parameters for many sensor applications. Auteurs: Lieuwe B. Leene;Timothy G. Constandinou; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2655 - 2665 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.016 mm2 12 b $\Delta \Sigma$ SAR With 14 fJ/conv. for Ultra Low Power Biosensor Arrays
 Résumé:The instrumentation systems for implantable brain–machine interfaces represent one of the most demanding applications for ultra low-power analogue-to-digital-converters (ADC) to date. To address this challenge, this paper proposes a $\Delta \Sigma$ SAR topology for very large sensor arrays that allows an exceptional reduction in silicon footprint by using a continuous time 0–2MASH topology. This configuration uses a specialized FIR window to decimate the $\Delta \Sigma$ modulator output and reject mismatch errors from the SAR quantizer, which mitigates the overhead from dynamic element matching techniques commonly used to achieve high precision. A fully differential prototype was fabricated using $0.18\,\mu$ m CMOS to demonstrate 10.8 ENOB precision with a 0.016 mm2 silicon footprint. Moreover, a 14fJ/conv figure-of-merit can be achieved, while resolving signals with the maximum input amplitude of ±1.2 Vpp sampled at 200 kS/s. The ADC topology exhibits a number of promising characteristics for both high speed and ultra low-power systems due to the reduced complexity, switching noise, sampling load, and oversampling ratio, which are critical parameters for many sensor applications. Auteurs: Lieuwe B. Leene;Timothy G. Constandinou; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2655 - 2665 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.016 mm2 12 b $\Delta \Sigma$ SAR With 14 fJ/conv. for Ultra Low Power Biosensor Arrays
 Résumé:The instrumentation systems for implantable brain–machine interfaces represent one of the most demanding applications for ultra low-power analogue-to-digital-converters (ADC) to date. To address this challenge, this paper proposes a $\Delta \Sigma$ SAR topology for very large sensor arrays that allows an exceptional reduction in silicon footprint by using a continuous time 0–2MASH topology. This configuration uses a specialized FIR window to decimate the $\Delta \Sigma$ modulator output and reject mismatch errors from the SAR quantizer, which mitigates the overhead from dynamic element matching techniques commonly used to achieve high precision. A fully differential prototype was fabricated using $0.18\,\mu$ m CMOS to demonstrate 10.8 ENOB precision with a 0.016 mm2 silicon footprint. Moreover, a 14fJ/conv figure-of-merit can be achieved, while resolving signals with the maximum input amplitude of ±1.2 Vpp sampled at 200 kS/s. The ADC topology exhibits a number of promising characteristics for both high speed and ultra low-power systems due to the reduced complexity, switching noise, sampling load, and oversampling ratio, which are critical parameters for many sensor applications. Auteurs: Lieuwe B. Leene;Timothy G. Constandinou; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2655 - 2665 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.016 mm2 12 b $\Delta \Sigma$ SAR With 14 fJ/conv. for Ultra Low Power Biosensor Arrays
 Résumé:The instrumentation systems for implantable brain–machine interfaces represent one of the most demanding applications for ultra low-power analogue-to-digital-converters (ADC) to date. To address this challenge, this paper proposes a $\Delta \Sigma$ SAR topology for very large sensor arrays that allows an exceptional reduction in silicon footprint by using a continuous time 0–2MASH topology. This configuration uses a specialized FIR window to decimate the $\Delta \Sigma$ modulator output and reject mismatch errors from the SAR quantizer, which mitigates the overhead from dynamic element matching techniques commonly used to achieve high precision. A fully differential prototype was fabricated using $0.18\,\mu$ m CMOS to demonstrate 10.8 ENOB precision with a 0.016 mm2 silicon footprint. Moreover, a 14fJ/conv figure-of-merit can be achieved, while resolving signals with the maximum input amplitude of ±1.2 Vpp sampled at 200 kS/s. The ADC topology exhibits a number of promising characteristics for both high speed and ultra low-power systems due to the reduced complexity, switching noise, sampling load, and oversampling ratio, which are critical parameters for many sensor applications. Auteurs: Lieuwe B. Leene;Timothy G. Constandinou; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2655 - 2665 Editeur: IEEE Document complet vers site de l'éditeur
» A 1.1-mW Ground Effect-Resilient Body-Coupled Communication Transceiver With Pseudo OFDM for Head and Body Area Network
 Résumé:This paper presents a body-coupled communication (BCC) transceiver (TRX) that mitigates all the practical impairments of the body channel at once. The proposed pseudo orthogonal frequency-division multiplexing (P-OFDM) TRX combines baseband BPSK–OFDM with frequency-shift keying (FSK) to alleviate the impacts of variable ground effect and variable skin-electrode contact impedance, which have been the two major issues on the BCC. It can tolerate up to 20 dB of channel gain variation with measured bit error rate improvement of >70% compared to FSK modulation alone. The RC relaxed contact impedance monitor continuously monitors and compensates the variable skin-electrode contact impedance at both transmitter (TX) and receiver (RX). The proposed power-gated 8-point inverse fast Fourier transform/fast Fourier transform with no floating-point multipliers (FPMs) reduces the gate count and power by 54% and 30% compared to conventional FPMs, respectively. Additionally, the simple floating-point adder (FPA) reduces the gate count and energy consumption by 34% and 20% compared to conventional FPAs, respectively. A high input impedance glitch-free FSK demodulation RX with variable threshold limiter and all digital cycle correction is also proposed to support a scalable data rate (200 Kbps–2 Mbps). The 0.54 mm2 TRX in 65-nm CMOS consumes 1.1 mW. Auteurs: Wala Saadeh;Muhammad Awais Bin Altaf;Haneen Alsuradi;Jerald Yoo; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2690 - 2702 Editeur: IEEE Document complet vers site de l'éditeur
» A 1.62–5.4-Gb/s Receiver for DisplayPort Version 1.2a With Adaptive Equalization and Referenceless Frequency Acquisition Techniques
 Résumé:We present a 1.62–5.4-Gb/s receiver for DisplayPort version 1.2a and propose an adaptive equalizer (EQ) with a peak-level comparison technique for eye measurement. A single comparator and an up/down unmatched-current charge pump are used to realize a simpler EQ architecture with low power dissipation. A referenceless frequency acquisition technique is also proposed. A time-to-digital converter-based pulsewidth detector supports the referenceless frequency acquisition within the range of 1.62–5.4 Gb/s. An XOR-gate-embedded charge pump and a half-rate linear phase detector were used to improve the jitter tolerance (JTOL) performance. The measured eye opening of the proposed EQ at 5.4 Gb/s was 0.68 UI with a −20-dB loss channel. The proposed receiver passed all the JTOL tests of the DisplayPort compliance specification version 1.2b. The power consumption of the receiver was 36.8 mW at 5.4 Gb/s. The receiver occupied a core area of 0.265 mm2 using 65-nm CMOS process technology. Auteurs: Sewook Hwang;Junyoung Song;Yeonho Lee;Chulwoo Kim; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2691 - 2702 Editeur: IEEE Document complet vers site de l'éditeur
» A 1.9-mW 750-kb/s 2.4-GHz F-OOK Transmitter With Symmetric FM Template and High-Point Modulation PLL
 Résumé:This paper describes a frequency-domain on-off keying (F-OOK) modulation method which utilizes power detection of both a carrier and a sideband by modulating the carrier frequency with a pre-selected modulation template. Compared to on-off keying and binary frequency-shift keying modulations, more efficient bandwidth control is achieved for the same data rate with a symmetric FM template. Since the proposed modulation maintains the average center frequency of the carrier regardless of data pattern, the F-OOK signal can be generated by using only the high-pass modulation path of the conventional phase-locked loop-based two-point modulator, thus relaxing design complexity. A prototype transmitter implemented in 65-nm CMOS consumes 1.9 mW from a 0.8-V supply with a data rate of 750 kb/s, achieving an energy efficiency of 2.5 nJ/b. Auteurs: Yining Zhang;Ranran Zhou;Woogeun Rhee;Zhihua Wang; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2627 - 2635 Editeur: IEEE Document complet vers site de l'éditeur
» A 10-b 800-MS/s Time-Interleaved SAR ADC With Fast Variance-Based Timing-Skew Calibration
 Résumé:This paper presents a time-interleaved (TI) SAR analog-to-digital converter (ADC) with a fast variance-based timing-skew calibration technique. It uses a single-comparator-based window detector (WD) to calibrate the timing skew. The WD can suppress variance estimation errors and allow precise variance estimation from a significantly small number of samples. It has low-hardware cost and orders of magnitude faster convergence speed compared to prior variance-based timing-skew calibration technique. The proposed technique brings collateral benefit of offset mismatch calibration. After timing-skew calibration, a prototype 10-b 800-MS/s ADC in 40-nm CMOS achieves the Nyquist-rate SNDR of 48 dB and consumes 4.9 mW, leading to the Walden FoM of 29.8-fJ/conversion step. Auteurs: Jeonggoo Song;Kareem Ragab;Xiyuan Tang;Nan Sun; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2563 - 2575 Editeur: IEEE Document complet vers site de l'éditeur
» A 120-kV, 5-kA Multipurpose Pulsed-Power Generator Using a Semiconductor Switch and Magnetic Pulse Compression
 Résumé:This paper describes a high-frequency pulsed-power generator for various industrial applications such as water treatment, food and medical apparatus for sterilization, or polluted gas treatment. The system is made of silicon-controlled rectifier as a main trigger switch, capacitors, two-stage magnetic pulse compression stages, and a linear transformer to generate a maximum of 120-kV, 5-kA pulse. The parameters obtained through the development are: output voltage: 120 kV (maximum), pulse repetition ration: 300 pulse per second, pulsewidth: $0.25~\mu \text{s}$ , and mean power: 30 kW. The designed pulsed-power generator is confirmed to be used effectively for many high-voltage pulsed-power applications related to environmental industry by simulation and experiments. Auteurs: Sung Roc Jang;Geun Hie Rim;Chan Gi Cho;Seung Ho Song;Su Mi Park;Hong Je Ryoo; Apparue dans: IEEE Transactions on Plasma Science Date publication: 10.-2017, volume: 45, issue:10, pages: 2678 - 2682 Editeur: IEEE Document complet vers site de l'éditeur
» A 17.4-b Delta-Sigma Capacitance-to-Digital Converter for One-Terminal Capacitive Sensors
 Résumé:In this brief, we present a capacitance-to-digital converter (CDC) for one-terminal capacitive sensors. The designed CDC implements a digital correction technique to reduce nonidealities and noises, such as the offset, 1/f noise, and power supply noise. This correction technique can also minimize effectively the complexity of the analog front-end circuit. All sensor functions, including analog circuits (delta-sigma CDC, bandgap reference, and voltage regulator) and digital logics (microprocessor, memories, and interface logics), are integrated into a single chip and occupy approximately 90% of the area. The chip is fabricated in a 0.18-$\mu\mbox{m}$ standard CMOS process, which does not have a deep n-well stage. The analog and digital circuits, including the digital input/output pads, must share the same substrate in this design. However, the measurement results demonstrate highly effective resolutions of 16 to 17.4 b, which are achieved with different conversion times. Auteurs: Youngjae Jung;Quanzhen Duan;Jeongjin Roh; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1122 - 1126 Editeur: IEEE Document complet vers site de l'éditeur
» A 17.5-fJ/bit Energy-Efficient Analog SRAM for Mixed-Signal Processing
 Résumé:An energy-efficient analog SRAM (A-SRAM) is proposed to eliminate redundant analog-to-digital (A/D) and digital-to-analog (D/A) conversion in mixed-signal systems, such as neuromorphic chips and neural networks. D/A conversion is integrated into the SRAM readout by charge sharing of the proposed split bitline (BL). Also, A/D conversion is integrated into the SRAM write operation with the successive approximation method in the proposed input–output block. Also, a configurable SRAM bitcell array is proposed to allocate the converted digital data without unfilled bitcells. The multirow access decoder selects multiple bitcells in a single column and configures the bitcell array by controlling the BL switches to split BLs. The proposed A-SRAM is implemented using the 65-nm CMOS technology. It achieves 17.5-fJ/bit energy-efficiency and 21-Gbit/s throughput for the analog readout, which are 64% and 1.3 times better than those of the conventional SRAM followed by a digital-to-analog converter (DAC). Also, the area is reduced by 91% compared with the conventional SRAM with analog-to-digital converter (ADC) and DAC. Auteurs: Jinsu Lee;Dongjoo Shin;Youchang Kim;Hoi-Jun Yoo; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2714 - 2723 Editeur: IEEE Document complet vers site de l'éditeur
» A 170-GHz Fully Integrated Single-Chip FMCW Imaging Radar with 3-D Imaging Capability
 Résumé:A 170-GHz fully integrated single-chip heterodyne frequency modulated continuous-wave (FMCW) imaging radar using a 130-nm SiGe BiCMOS technology ( $f_{T}/f_{\max } = 220/280$ GHz) is reported. This system demonstrates a wide bandwidth of 27.5 GHz (16.3%) at a center frequency of 168 GHz. A design methodology to maximize the tuning range of the voltage-controlled oscillator (VCO) is presented. A co-design of the VCO, coupler, and antenna is performed to minimize the chip area and the dc power consumption. The transmitter radiates a peak power of −1 dBm with a dc-to-RF efficiency of 1.42%. At the receiver side, a subharmonic mixer is used for signal down-conversion. The system achieves a measured sensitivity of 87 fW with a total dc power consumption of 67 mW. The prototype is capable of forming 2-D and 3-D images with a range resolution of 7 mm. To the best of our knowledge, this fully integrated imaging radar demonstrates the highest sensitivity and radiation efficiency among all imaging systems around 200 GHz. Moreover, the system is capable of practical 2-D and 3-D imaging with significantly lower dc power consumption compared to the state-of-the-art FMCW radars. Auteurs: Ali Mostajeran;Andreia Cathelin;Ehsan Afshari; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2721 - 2734 Editeur: IEEE Document complet vers site de l'éditeur
» A 2-Gb/s/ch Data-Dependent Swing-Limited On-Chip Signaling for Single-Ended Global I/O in SDRAM
 Résumé:This brief proposes a data-dependent swing-limited on-chip signaling for single-ended global I/O in the SDRAM in a 0.13-$\mu\mbox{m}$ CMOS technology. The SDRAM has multiple global I/O lines for sending and receiving data, which results in a large delay deviation owing to the multi-drop bus topology and a large RC load. Minimizing the delay and its deviation improves the speed of the SDRAM. With the proposed technique, the maximum speed is 2 Gb/s/ch, which is increased by more than 120% under the same channel condition. The power consumption is also reduced compared to that of the conventional scheme; the energy efficiency is 104 fJ/b/mm, respectively. Auteurs: Jungtaek You;Junyoung Song;Chulwoo Kim; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1207 - 1211 Editeur: IEEE Document complet vers site de l'éditeur
» A 2-GS/s 8-bit Time-Interleaved SAR ADC for Millimeter-Wave Pulsed Radar Baseband SoC
 Résumé:This paper presents a 2-GS/s 8-bit 16 $\times$ time-interleaved (TI) analog-to-digital converter (ADC) for a millimeter-wave pulsed radar baseband system-on-chip (SoC). To suppress sampling timing errors among sub-ADCs, a foreground timing-skew calibration technique with small additional circuits is proposed. Measured spurious-free dynamic range and signal-to-noise distortion ratio at 1-GHz full Nyquist is, therefore, enhanced by 16 and 11 dB, respectively. Unlike conventional calibration techniques based on redundant ADCs or complicated digital calculations, additional circuit components are only several small resistors and a capacitor, resulting in only 0.4% area penalty. This area saving enables the compact integration of the radar baseband SoC with digital beamforming, where eight-channel TI-ADCs occupy the dominant chip area otherwise. Even though this is foreground, no system performance is sacrificed because the calibration sequence is closed loop and fast enough to be executed during an existing calibration interval in a periodic beam transmission sequence. The TI-ADCs are embedded on industrial SoC in a 40-nm CMOS process. The power consumption including the input buffer and the reference buffer is 54.2 mW from a 1.1-V supply, and figure of merit is 355 fJ/conversion step. Auteurs: Takuji Miki;Toshiaki Ozeki;Jun-ichi Naka; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2712 - 2720 Editeur: IEEE Document complet vers site de l'éditeur
» A 32.75-Gb/s Voltage-Mode Transmitter With Three-Tap FFE in 16-nm CMOS
 Résumé:This paper describes a 32.75-Gb/s voltage-mode transmitter (TX) with three-tap feed forward equalization that is fabricated in a 16-nm FinFET CMOS technology. The TX uses a dual regulator architecture to allow independent control of output swing, output common-mode, and equalization. A hybrid impedance control scheme is presented where the total number of driver slices is used for coarse impedance control, and analog loop-based voltage control is used for fine impedance control of the TX. A finite-impulse response compensation circuit to compensate for the data dependent current due to equalization is also presented. The TX consumes 120.8 mW with 0.9- and 1.2-V supplies, provides 0.25–0.9 Vpp output swing, and achieves total jitter of 6.49 ps–pp and random jitter of 220 fs–rms at 32.75 Gb/s with bit error rate of 1e-12. Auteurs: Kok Lim Chan;Kee Hian Tan;Yohan Frans;Jay Im;Parag Upadhyaya;Siok Wei Lim;Arianne Roldan;Nakul Narang;Chin Yang Koay;Hongyuan Zhao;Ping-Chuan Chiang;Ken Chang; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2663 - 2678 Editeur: IEEE Document complet vers site de l'éditeur
» A 4.2-mW 77.1-dB SNDR 5-MHz BW DT 2-1 MASH $\Delta \Sigma$ Modulator With Multirate Opamp Sharing
 Résumé:This paper presents a discrete time 2-1 MASH Delta-Sigma ( $\Delta \Sigma )$ modulator with multirate opamp sharing for analog-to-digital converters, targeting the optimization of power efficiency in active blocks, such as opamps and quantizers. Through the allocation of different settling times to the opamps and by adopting the multirate technique, the power of the shared opamps is utilized more efficiently, and the 4-b successive approximation register quantizer and the data weighted averaging block in the first stage enjoy additional operation time. Moreover, a detailed analysis and related simulations are presented to validate the enhanced opamp power efficiency in the proposed sharing scheme. The 65-nm CMOS experimental chip running at multirate 120/240 MHz achieves a mean signal-to-noise and distortion ratio (SNDR) of 77.1 dB for a 5-MHz bandwidth, consuming 4.2 mW from a 1.2 V supply and occupying 0.066-mm2 core area. It exhibits a Walden figure of merit (FoM) of 69.7 fJ/conv-step and a Schreier FoM of 167.9 dB based on SNDR. Auteurs: Liang Qi;Sai-Weng Sin;Seng-Pan U;Franco Maloberti;Rui Paulo Martins; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 10.-2017, volume: 64, issue:10, pages: 2641 - 2654 Editeur: IEEE Document complet vers site de l'éditeur
» A 41.3/26.7 pJ per Neuron Weight RBM Processor Supporting On-Chip Learning/Inference for IoT Applications
 Résumé:An energy-efficient restricted Boltzmann machine (RBM) processor (RBM-P) supporting on-chip learning and inference is proposed for machine learning and Internet of Things (IoT) applications in this paper. To train a neural network (NN) model, the RBM structure is applied to supervised and unsupervised learning, and a multi-layer NN can be constructed and initialized by stacking multiple RBMs. Featuring NN model reduction for external memory bandwidth saving, low power neuron binarizer (LPNB) with dynamic clock gating and area-efficient NN-like activation function calculators for power reduction, user-defined connection map (UDCM) for both computation time and bandwidth saving, and early stopping (ES) mechanism for learning process, the proposed system integrates 32 RBM cores with maximal 4k neurons per layer and 128 candidates per sample for machine learning applications. Implemented in 65nm CMOS technology, the proposed RBM-P chip costs 2.2 M gates and 128 kB SRAM with 8.8 mm2 area. Operated at 1.2 V and 210 MHz, this chip achieves 7.53G neuron weights (NWs) and 11.63G NWs per second with 41.3 and 26.7 pJ per NW for learning and inference, respectively. Auteurs: Chang-Hung Tsai;Wan-Ju Yu;Wing Hung Wong;Chen-Yi Lee; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2601 - 2612 Editeur: IEEE Document complet vers site de l'éditeur
» A 48-MHz Differential Crystal Oscillator With 168-fs Jitter in 28-nm CMOS
 Résumé:A 168-fs rms jitter, 48-MHz differential crystal oscillator based on a new active inductor biasing circuit achieves differential operation with low noise, power, and area overhead. This architecture has two significant advantages compared to the single-ended crystal oscillators that are normally used: 1) this circuit rejects power supply noise and interference which leads to lower jitter and 2) the crystal oscillator-induced spurious tones are smaller and therefore less detrimental to sensitive blocks (e.g., LNA) in RF radios. This paper theoretically analyzes the differential crystal oscillator and provides detailed design considerations. A prototype requires half the power and 80% less area than previously reported differential crystal oscillators. Implemented in a 28-nm LP CMOS process, it draws 1.5 mA from a 1-V supply and occupies 0.013 mm2. Auteurs: Yashar Rajavi;Mohammad Mahdi Ghahramani;Alireza Khalili;Amirpouya Kavousian;Beomsup Kim;Michael P. Flynn; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2735 - 2745 Editeur: IEEE Document complet vers site de l'éditeur
» A 5-GHz Subsampling PLL-Based Spread-Spectrum Clock Generator by Calibrating the Frequency Deviation
 Résumé:This brief presents a spread-spectrum clock generator (SSCG) based on a subsampling phase-locked loop (SSPLL) by calibrating the spreading ratio. The proposed SSCG has a low jitter performance owing to the low in-band phase noise performance of the SSPLL. To achieve a spread-spectrum clocking, the direct voltage-controlled oscillator modulation method is used owing to the absence of a frequency divider. However, the spreading ratio ( ${\delta }$ ) can be varied by process, voltage, and temperature variations. Automatic calibration technique is proposed for a 5000-ppm spreading ratio at 5 GHz. The proposed SSCG achieves a 21-dB electromagnetic interference reduction, has a −104-dBc/Hz phase noise at 200-kHz offset, and consumes 7 mW and occupies a 0.39-mm2 area in a 65-nm CMOS process. Auteurs: Sang-Geun Bae;Gyungmin Kim;Chulwoo Kim; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1132 - 1136 Editeur: IEEE Document complet vers site de l'éditeur
» A 60-GHz CMOS Broadband Receiver With Digital Calibration, 20-to-75-dB Gain, and 5-dB Noise Figure
 Résumé:We present a 60-GHz broadband heterodyne receiver with digital calibration. In the LNA, the low-coupling coefficient transformer-based matching network and the tail switch technique are used to achieve broadband operation and increase the gain tuning range with well-defined gain steps, respectively. In the down-conversion mixer, the inductive peaking technique is employed to extend its bandwidth. In the demodulator, inverter-based $g_{m}$ stages are used to improve its gain and linearity performance. The receiver gain tuning and the I/Q mismatch calibration are achieved by utilizing digital gain control and phase tuning schemes. The measurement shows that the receiver achieves a 20-to-75-dB conversion gain, a 5-dB noise figure (NF), and a good gain flatness performance within the complete 60-GHz band (i.e., 57–66 GHz). Measured with a 60-GHz transmitter, the error vector magnitude (EVM) is better than 10% (−20 dB) in each single channel. Fabricated in a 65-nm CMOS, the receiver occupies a silicon area of 1.9 mm $\times$ 0.7 mm (including all pads) and consumes 102.4-mW dc power. Auteurs: Yuan Chai;Xiaokang Niu;Long He;Lianming Li;Tie Jun Cui; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3989 - 4001 Editeur: IEEE Document complet vers site de l'éditeur
» A 65-nm ReRAM-Enabled Nonvolatile Processor With Time-Space Domain Adaption and Self-Write-Termination Achieving $> 4\times$ Faster Clock Frequency and $> 6\times$ Higher Restore Speed
 Résumé:With an ever-increasing demand for energy efficiency, processors with instant-on and zero leakage features are highly appreciated in energy harvesting as well as “normally off” applications. Recently, zero-standby power and fast switching nonvolatile processors (NVPs) have been proposed based on emerging nonvolatile memories (NVMs), such as ferroelectric RAM or spin-transfer-torque magnetic RAM. However, previous NVPs store all data to NVM upon every power interruption, resulting in high-energy consumption and degraded NVM endurance. This paper presents a 65-nm fully CMOS-logic-compatible ReRAM-based NVP supporting time-space domain adaption. It incorporates adaptive nonvolatile controller, nonvolatile flip-flops, and nonvolatile static random access memory (nvSRAM) with self-write termination. Data redundancy in both time and space domain is fully exploited to reduce store/restore time/energy and boost clock frequency. The NVP operates at >100 MHz and achieves 20 ns/0.45 nJ restore time/energy, realizing >6 $\times$ and >6000 $\times$ higher speed and energy efficiency of restore and >4 $\times$ faster operating frequency compared with that of state of the art. Auteurs: Zhibo Wang;Yongpan Liu;Albert Lee;Fang Su;Chieh-Pu Lo;Zhe Yuan;Jinyang Li;Chien-Chen Lin;Wei-Hao Chen;Hsiao-Yun Chiu;Wei-En Lin;Ya-Chin King;Chrong-Jung Lin;Pedram Khalili Amiri;Kang-Lung Wang;Meng-Fan Chang;Huazhong Yang; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2769 - 2785 Editeur: IEEE Document complet vers site de l'éditeur
» A 7.9-GHz Transformer-Feedback Quadrature Oscillator With a Noise-Shifting Coupling Network
 Résumé:A noise-shifting coupling network is proposed for nonlinear passively coupled quadrature voltage-controlled oscillators (QVCOs). Both detailed analysis and circuit implementation demonstrate that the noise contribution by the coupling network can be minimized by re-aligning the phases of the noise modulation function and the impulse sensitivity function with a reduced magnitude. In addition, the QVCO with the proposed coupling network also incorporates the transformer-feedback technique to improve its performance in terms of phase noise, quadrature phase error, and low supply voltage. Fabricated in a 65-nm CMOS process, the QVCO prototype operating at 7.9-GHz measures phase noise at 10-MHz offset frequency of −143 dBc/Hz and minimum quadrature phase error of 0.23° while consuming 27.2 mW with a 0.8-V supply voltage. Auteurs: Bingwei Jiang;Howard C. Luong; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2636 - 2646 Editeur: IEEE Document complet vers site de l'éditeur
» A 79-GHz 2 $\times$ 2 MIMO PMCW Radar SoC in 28-nm CMOS
 Résumé:In this paper, the concept of phase modulated MIMO radars is explained and demonstrated with a 28-nm CMOS fully integrated 79-GHz radar SoC. It includes two transmitters, two receivers, and the mm-wave frequency generation. The receivers’ outputs are digitized by on-chip ADCs and processed by a custom designed digital core, which performs correlation and accumulation with a pseudorandom sequence used in transmission. The SoC consumes 1 W to achieve 7.5 cm range resolution. A module with antennas allows for 5° resolution over ±60° elevation and azimuth scan in 2 $\times$ 2 code domain MIMO operation. A 4 $\times$ 4 MIMO system is also demonstrated by means of two SoCs mounted on the same module. Auteurs: Davide Guermandi;Qixian Shi;Andy Dewilde;Veerle Derudder;Ubaid Ahmad;Annachiara Spagnolo;Ilja Ocket;André Bourdoux;Piet Wambacq;Jan Craninckx;Wim Van Thillo; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2613 - 2626 Editeur: IEEE Document complet vers site de l'éditeur
» A Band-Weighted Support Vector Machine Method for Hyperspectral Imagery Classification
 Résumé:A band-weighted support vector machine (BWSVM) method is proposed to classify hyperspectral imagery (HSI). The BWSVM presents an L1 penalty term of band weight vector to regularize the regular SVM model. The L1 norm regularization term guarantees the sparsity of band weights and describes potentially divergent contributions from different bands in modeling the binary SVM model. The BWSVM adopts the KerNel iterative feature extraction algorithm to minimize the nonconvex program. It linearizes nonlinear kernels and iteratively optimizes two convex subproblems with respect to both sample coefficients and band weights. The class label is determined by picking the largest sample coefficients from all its binary models of BWSVM. Two popular HSI data sets are utilized to testify the classification performance of BWSVM. Experimental results show that the BWSVM outperforms three state-of-the-art classifiers including SVM, random forest, and k-nearest neighbor. Auteurs: Weiwei Sun;Chun Liu;Yan Xu;Long Tian;Weiyue Li; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1710 - 1714 Editeur: IEEE Document complet vers site de l'éditeur
» A Bootstrapped PMHT with Feature Measurements
 Résumé:The probabilistic multi-hypothesis tracker (PMHT), a tracking algorithm of considerable theoretical elegance based on the expectation-maximization algorithm, will be considered for the problem of multiple target tracking with multiple sensors in clutter. In addition to position observations, continuous measurements associated with the unique, constant—and statistically unknown—feature of each target are incorporated to jointly estimate the states and features of the targets for the sake of tracking and classification, leading to a bootstrapped implementation of the PMHT. In addition, the information matrix for the stacked vector of states for all the targets at all the time steps during the observation time is derived. Auteurs: Qin Lu;Katherine Domrese;Peter Willett;Yaakov Bar-Shalom;Krishna Pattipati; Apparue dans: IEEE Transactions on Aerospace and Electronic Systems Date publication: 10.-2017, volume: 53, issue:5, pages: 2559 - 2571 Editeur: IEEE Document complet vers site de l'éditeur
» A Bridgeless Controlled Rectifier for Single Split-Phase Systems
 Résumé:An unidirectional single-phase three-wire rectifier is proposed in this paper. Such topology is composed of a noncontrolled leg, two controlled legs, and a capacitor bank. A suitable model, pulse-width modulation, and control strategies of the system are proposed as well. The control strategy includes the synchronization method, in which it imposes the grid currents with the same phase angle of the voltages generated by the rectifier. This method ensures sinusoidal grid currents and mitigates the zero-crossover distortions normally caused by the use of diodes. A comprehensive comparison with two conventional configurations is also presented in this paper. Simulation and experimental results are also presented for validation purposes. Auteurs: Nustenil Segundo de Moraes Lima Marinus;Euzeli Cipriano dos Santos;Cursino Brandão Jacobina;Nady Rocha;Nayara Brandão de Freitas; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4708 - 4717 Editeur: IEEE Document complet vers site de l'éditeur
» A Broadband Circular Polarizer Based on Cross-Shaped Composite Frequency Selective Surfaces
 Résumé:A cross-shaped composite with frequency selective surfaces is applied in the design of a broadband polarizer. The structure is multilayer, and the unit cell of each layer consists of a composite cross and a metal strip. The design takes advantage of both the similar amplitude and the stable phase difference of nearly 90° of the two orthogonal components of transmitted waves. The bandwidth of the polarizer reaches 74%, from 5.15 to 11.20 GHz, which is able to generate circular-polarization waves from incident linear waves. A sample polarizer is fabricated and tested. According to the measurement results, the polarizer operates from 5.75 to 11.20 GHz at normal incidence. In addition, its working frequency band can still cover the range of 5.80 to 11.00 GHz when the incident angle increases to 20°. Auteurs: Wei Zhang;Jian-Ying Li;Jian Xie; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5623 - 5627 Editeur: IEEE Document complet vers site de l'éditeur
» A Broadband VHF/UHF-Loaded Dipole Antenna in the Vicinity of a Human Body
 Résumé:A broadband dipole antenna with a very simple low-cost mechanical structure is proposed. This dipole of the height of 173 cm with inductor/resistor (LR) loading circuits is designed to operate in the frequency range of 30–512 MHz—hence a 17:1 bandwidth (178%). By choosing the optimized location of LR loads, the radiation pattern is controlled. Meanwhile, the VSWR 1:3.5 is adjusted by an input matching circuit, tuning a number of LR loads, and using a transmission line transformer. The impedance matching is better than −6.5 dB in whole frequency bandwidth. The antenna gain is gradually increased from −20 dBi at 30 MHz to −2 dBi at 512 MHz. The manufactured prototype is presented along with its measured characteristics which map well onto software simulated counterparts. The antenna is considered to be used in portable applications. Therefore, the simulations and the measurements are conducted near the human body. A simple model of the adult human body at the frequency band of the proposed antenna is used, which helps to study the effects of the human on the antenna performance. Moreover, the electromagnetic exposure on the human body is investigated. Experimental evidence is presented to verify the conclusion. Auteurs: N. Amani;A. Jafargholi;R. Pazoki; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5577 - 5582 Editeur: IEEE Document complet vers site de l'éditeur
» A Broadband, Rectangular, and Self-Sustained Optical Frequency Comb Generation Employing Recirculation Frequency Shifter
 Résumé:To generate a self-sustained rectangular optical frequency comb (OFC) with tunable spacing and bandwidth, we propose and experimentally demonstrate a novel scheme by using an optoelectronic oscillator employing recirculation frequency shifter (RFS) loop. In this scheme, the oscillating signal is separated to drive the Mach–Zehnder modulator (MZM) in the oscillation loop and the inphase/quadrature modulator in the RFS loop separately. Then more than 50-tone OFCs, which have a rectangular spectral profile and the flatness better than 6 dB, are obtained with 8-GHz spacing and 10-GHz spacing by tuning the center frequency of the microwave filter respectively. Besides, the phase noise of the driving signals are both lower than $-$ 110 dBc/Hz at 10 kHz offset frequency. Auteurs: Jingliang Liu;Anni Liu;Jian Dai;Yue Zhou;Jianqiang Li;Yitang Dai;Feifei Yin;Kun Xu; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 7 Editeur: IEEE Document complet vers site de l'éditeur
» A Circuit-Driven Design Methodology for a Circular Polarizer Based on Modified Jerusalem Cross Grids
 Résumé:This paper presents an accelerated methodology to design a circular polarizer based on modified Jerusalem cross unit cells. The proposed three-layer planar polarizer features a high transparency to both TE and TM polarized fields while providing a quadrature phase difference between them, as required for the generation of circularly polarized fields. The structure is designed employing a circuit-driven approach in which two independent equivalent circuits describe the behavior of TE and TM modes through the polarizer. Featuring a unit cell volume of $0.17\lambda _{0} \times 0.17\lambda _{0} \times 0.21\lambda _{0}$ , the polarizer offers axial ratios of less than 3 and 1 dB over 20% and 7% bandwidths around 20 GHz, respectively, with an insertion loss less than 0.4 dB. Full-wave numerical simulations and experimental measurements verify not only the performance of the proposed polarizer but also the accuracy of the circuit-driven approach and its ability as a design tool. Auteurs: Mehdi Hosseini;Sean Victor Hum; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5322 - 5331 Editeur: IEEE Document complet vers site de l'éditeur
» A Clustering Algorithm for Communication-Aware Scheduling of Task Graphs on Multi-Core Reconfigurable Systems
 Résumé:In this paper, a clustering algorithm called the Reconfigurable Dominant Sequence Clustering (ReDSC), is proposed. The experiments show that ReDSC reduces the parallel run time efficiently by 30 percent. Moreover, an empirical comparison of ReDSC with its peer in the multi-processor model, i.e., DSC algorithm, is provided and the results demonstrate the 35 percent improvement of ReDSC over DSC. Then, a hardware implementation of a dynamic scheduler for run-time communication-aware scheduling of hardware tasks is proposed. The proposed scheduler makes use of the ReDSC algorithm for allocating tasks to the processing reconfigurable cores, dynamically considering the communication costs. The simulation results illustrate the benefits of the proposed scheduler as compared to that of other static and basic schedulers in the technical literature. Auteurs: Amin Yoosefi;Hamid Reza Naji; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 10.-2017, volume: 28, issue:10, pages: 2718 - 2732 Editeur: IEEE Document complet vers site de l'éditeur
» A CMOS Front-End With Integrated Magnetoresistive Sensors for Biomolecular Recognition Detection Applications
 Résumé:The development of giant magnetoresistive (GMR) sensors has demonstrated significant advantages in nanomedicine, particularly for ultrasensitive point-of-care diagnostics. To this end, the detection system is required to be compact, portable, and low power consuming at the same time that a maximum signal to noise ratio is maintained. This paper reports a CMOS front-end with integrated magnetoresistive sensors for biomolecular recognition detection applications. Based on the characterization of the GMR sensor's signal and noise, CMOS building blocks (i.e., current source, multiplexers, and preamplifier) were designed targeting a negligible noise when compared with the GMR sensor's noise and a low power consumption. The CMOS front-end was fabricated using AMS $\mathrm{{\text{0.35}}\;\mu{\text{m}}}$ technology and the magnetoresistive sensors were post-fabricated on top of the CMOS chip with high yield ( ${\text{97.9}}\%$). Due to its low circuit noise (16 $\mathrm{{\text{nV}}/\sqrt{{\text{Hz}}}}$) and overall equivalent magnetic noise ( $\mathrm{{\text{11.5}}\;{\text{nT}}/\sqrt{{\text{Hz}}}}$), the full system was able to detect 250 nm magnetic nanoparticles with a circuit imposed signal-to-noise ratio degradation of only $-$1.4 dB. Furthermore, the low power consumption (6.5 mW) and small dimensions ($\mathrm{{\text{7.59: mm}}^{2}}$ ) of the presented solution guarantees the portability of the detection system allowing its usage at the point-of-care. Auteurs: Tiago Costa;Filipe A. Cardoso;José Germano;Paulo P. Freitas;Moisés S. Piedade; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 10.-2017, volume: 11, issue:5, pages: 988 - 1000 Editeur: IEEE Document complet vers site de l'éditeur
» A Combined Eulerian-Lagrangian Data Representation for Large-Scale Applications
 Résumé:The Eulerian and Lagrangian reference frames each provide a unique perspective when studying and visualizing results from scientific systems. As a result, many large-scale simulations produce data in both formats, and analysis tasks that simultaneously utilize information from both representations are becoming increasingly popular. However, due to their fundamentally different nature, drawing correlations between these data formats is a computationally difficult task, especially in a large-scale setting. In this work, we present a new data representation which combines both reference frames into a joint Eulerian-Lagrangian format. By reorganizing Lagrangian information according to the Eulerian simulation grid into a “unit cell” based approach, we can provide an efficient out-of-core means of sampling, querying, and operating with both representations simultaneously. We also extend this design to generate multi-resolution subsets of the full data to suit the viewer’s needs and provide a fast flow-aware trajectory construction scheme. We demonstrate the effectiveness of our method using three large-scale real world scientific datasets and provide insight into the types of performance gains that can be achieved. Auteurs: Franz Sauer;Jinrong Xie;Kwan-Liu Ma; Apparue dans: IEEE Transactions on Visualization and Computer Graphics Date publication: 10.-2017, volume: 23, issue:10, pages: 2248 - 2261 Editeur: IEEE Document complet vers site de l'éditeur
» A Compact Bandpass Wilkinson Power Divider With Ultra-Wide Band Harmonic Suppression
 Résumé:A Wilkinson power divider (WPD) with bandpass property and an ultra-wide band harmonic suppression is proposed in this letter. The frequency-selecting coupling structure is embedded to the conventional quarter-wavelength transmission line, which can realize an ultra-wide harmonic suppression with three transmission zeros. Short-ended meander line stubs are shunted at the both output ports for dc block and provide an extra transmission zero for the passband. The proposed WPD operates with a −20 dB bandwidth from 1.74 to 3.71 GHz with an ultra-wide stopband to suppress the dc, $3f_{0}$ , $5f_{0}$ , and $7f_{0}$ harmonic components. The proposed WPD has a compact size of 14.65 mm $\times19.64$ mm ( $0.19\lambda _{g} \times 0.25\lambda _{g})$ . Auteurs: Yang Wang;Xiao-Yu Zhang;Fu-Xing Liu;Jong-Chul Lee; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 888 - 890 Editeur: IEEE Document complet vers site de l'éditeur
» A Compact Gate Control and Voltage-Balancing Circuit for Series-Connected SiC MOSFETs and Its Application in a DC Breaker
 Résumé:This paper presents a novel compact circuit combining function of gate control and voltage balancing for series-connected silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET). Two series-connected SiC MOSFETs with the proposed circuit only require a single standard gate driver to achieve the gate control and voltage balancing during both steady-state and switching transition. Moreover, the proposed circuit is only composed of ten passive components. Therefore, the proposed circuit provides a low-cost and highly reliable method to increase the blocking voltage of the SiC MOSFET. The operation principles of the proposed circuit are theoretically analyzed. In addition, the high-blocking-voltage device is not only required in switching-mode power supply (SMPS) but also in dc-breaker applications. The proposed circuit is then modified to make it suitable to the dc-breaker applications. The simulation and experimental results validate the effectiveness and superiority of the proposed circuit in both SMPS and dc-breaker applications. Auteurs: Yu Ren;Xu Yang;Fan Zhang;Kangping Wang;Wenjie Chen;Laili Wang;Yunqing Pei; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8299 - 8309 Editeur: IEEE Document complet vers site de l'éditeur
» A Compact Model with Spin-Polarization Asymmetry for Nanoscaled Perpendicular MTJs
 Résumé:The aim of this paper is to introduce a compact model for perpendicular spin-transfer torque (STT)-magnetic tunnel junctions (MTJs) implemented in Verilog-A to assure easy integration with electrical circuit simulators. It takes into account the effects of voltage-dependent perpendicular magnetic anisotropy, temperature-dependent parameters, thermal heating/cooling, MTJ process variations, and the spin-torque asymmetry of the Slonczewski spin-polarization function in the switching process. This translates into a comprehensive modeling that was adopted to investigate the writing performance under voltage scaling of a $256\times256$ STT- magnetic random access memory array implemented at three different technology nodes. Obtained results show that scaling from 30- to 20-nm node allows a write energy saving of about 43%, while the supply voltage that assures the minimum-energy write operation increases. Auteurs: Raffaele De Rose;Marco Lanuzza;Massimiliano d’Aquino;Greta Carangelo;Giovanni Finocchio;Felice Crupi;Mario Carpentieri; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4346 - 4353 Editeur: IEEE Document complet vers site de l'éditeur
» A Comparative Analysis on Fully Integrated Spectral Broadening of Kerr Frequency Combs
 Résumé:Microresonator-based frequency combs have potential to achieve on-chip frequency metrology. To obtain high-power comb lines at f and 2f for self-referenced stabilization, we evaluate the feasibility of building a fully integrated comb generator with spectral broadening. Comparing two types of nonlinear waveguides based on Si and chalcogenides, we find that the system feasibility relies on integrated waveguide amplifiers. If with a high-gain amplifier, a dispersion-engineered chalcogenide waveguide is preferred. Otherwise, an Si waveguide performs better. Considering the immaturity of both on-chip amplification technologies for ultrafast pulses and hybrid integration of multiple nonlinear materials, it could be concluded that in near future it is not practical to achieve fully on-chip f-2f self-referenced comb stabilization via subsequent spectral broadening of a Kerr frequency comb. Alternatively, direct generation of octave-spanning Kerr combs via dispersion engineering still remains attractive. Auteurs: Jing Wang;Yuhao Guo;Henan Liu;Guifang Li;Lin Zhang; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 9 Editeur: IEEE Document complet vers site de l'éditeur
» A Compliant 3-Axis Fiber-Optic Force Sensor for Biomechanical Measurement
 Résumé:This paper presents the development of a flexible, multi-axis, intensity modulated-based fiber-optic force sensor for concurrently measuring normal and shear forces. The proposed sensor was prototyped to measure the three force components by monitoring the variation of the light intensity induced by a deformation as a result of the applied force. One end of the sensor incorporates three orthogonal reflective planes. The other end brings three pairs of fibers; one fiber connected to an LED, and the other to a light-to-voltage (LTV) converter in each pair. Upon the application of the force, the distance between the planes and the fiber tips changes, thus, the LTV voltage changes, enabling the simultaneous measurement of forces along three normal axes utilizing only one set of force measurement unit. The fabricated sensor was tested in both static and dynamic loading conditions as the experimental results have confirmed that the prototype has the capability to accurately measure the normal and shear forces in real time ranging from 0 to 1000 N and 0 to 140 N along the z, x, and y axes, respectively. The feasible applications of the sensor are ground reaction force measurements and robot–human collision detection. Sensor performance was evaluated for the cross-talk effects, which were found to be less than 5%. A nonlinear Hammerstein–Winer model is proposed to characterize the linear and nonlinear behavior of the sensor. The optimized results have shown a reduction of over 40% in the root mean-square errors in comparison with the linear estimation models. Auteurs: Osama Al-Mai;Mojtaba Ahmadi;Jacques Albert; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6549 - 6557 Editeur: IEEE Document complet vers site de l'éditeur
» A Comprehensive Comparison of Multiparty Secure Additions with Differential Privacy
 Résumé:This paper considers the problem of secure data aggregation (mainly summation) in a distributed setting, while ensuring differential privacy of the result. We study secure multiparty addition protocols using well known security schemes: Shamir's secret sharing, perturbation-based, and various encryptions. We supplement our study with our new enhanced encryption scheme EFT, which is efficient and fault tolerant.Differential privacy of the final result is achieved by either distributed Laplace or Geometric mechanism (respectively DLPA or DGPA), while approximated differential privacy is achieved by diluted mechanisms. Distributed random noise is generated collectively by all participants, which draw random variables from one of several distributions: Gamma, Gauss, Geometric, or their diluted versions. We introduce a new distributed privacy mechanism with noise drawn from the Laplace distribution, which achieves smaller redundant noise with efficiency. We compare complexity and security characteristics of the protocols with different differential privacy mechanisms and security schemes. More importantly, we implemented all protocols and present an experimental comparison on their performance and scalability in a real distributed environment. Based on the evaluations, we identify our security scheme and Laplace DLPA as the most efficient for secure distributed data aggregation with differential privacy. Auteurs: Slawomir Goryczka;Li Xiong; Apparue dans: IEEE Transactions on Dependable and Secure Computing Date publication: 10.-2017, volume: 14, issue:5, pages: 463 - 477 Editeur: IEEE Document complet vers site de l'éditeur
» A Computationally Efficient Lookup Table Based FCS-MPC for PMSM Drives Fed by Matrix Converters
 Résumé:Finite control set-model predictive control (FCS-MPC) is an interesting alternative for the control of drive systems. However, FCS-MPC requires a large amount of calculation, because it uses all feasible voltage vectors of a power converter for prediction and evaluation. This is an obstacle for its application when the number of voltage vectors of power converter is increased. The computational burden is more challenging when the control objectives are increased. At the same time, matrix converter is an attractive alternative to conventional back-to-back converters with dc link. However, implementation of FCS-MPC for a matrix converter is computationally expensive due to the 27 feasible voltage vectors of the matrix converter. In this paper, a Lookup table is used to reduce the candidate voltage vectors that make the FCS-MPC computationally efficient for matrix converter-fed permanent-magnet synchronous motors. This approach is implemented experimentally and is compared with the conventional approach to evaluate its performance. Auteurs: Mohsen Siami;Davood Arab Khaburi;Marco Rivera;Jose Rodríguez; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7645 - 7654 Editeur: IEEE Document complet vers site de l'éditeur
» A Conflict-Free Replicated JSON Datatype
 Résumé:Many applications model their data in a general-purpose storage format such as JSON. This data structure is modified by the application as a result of user input. Such modifications are well understood if performed sequentially on a single copy of the data, but if the data is replicated and modified concurrently on multiple devices, it is unclear what the semantics should be. In this paper we present an algorithm and formal semantics for a JSON data structure that automatically resolves concurrent modifications such that no updates are lost, and such that all replicas converge towards the same state (a conflict-free replicated datatype or CRDT). It supports arbitrarily nested list and map types, which can be modified by insertion, deletion and assignment. The algorithm performs all merging client-side and does not depend on ordering guarantees from the network, making it suitable for deployment on mobile devices with poor network connectivity, in peer-to-peer networks, and in messaging systems with end-to-end encryption. Auteurs: Martin Kleppmann;Alastair R. Beresford; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 10.-2017, volume: 28, issue:10, pages: 2733 - 2746 Editeur: IEEE Document complet vers site de l'éditeur
» A Control Scheme for Automatic Level Crossings Under the ERTMS/ETCS Level 2/3 Operation
 Résumé:Level crossing (LC) safety is a crucial issue for railway operators and infrastructure managers. Accidents at LCs give rise to serious material and human damage, while seriously impacting the reputation of railway safety. In particular, some typical scenarios are behind the main part of train-car collisions, which occur at LCs. On the other hand, European Rail Traffic Management System (ERTMS) is the standard railway control-command and signaling system that is currently being implemented throughout Europe and elsewhere. The aim is to ensure railway interoperability while enhancing safety and competitiveness of the railway transportation. ERTMS specifications only provide a rough description when dealing with LC control. This paper elaborates on a functional control architecture for automatic LCs in the context of ERTMS operation Levels 2 and 3. Indeed, these operation levels ensure a continuous knowledge of train location thanks to the Global System for Mobile Communications—Railways link between the trains and the Radio Block Center. Hence, the established LC control scheme aims to ensure an optimal LC command based on the information regarding the train location and, thereby, prevent some potential risky scenarios and improve the global safety at LCs. To achieve this, a generic methodology is employed. First, a formal behavioral model is developed using the time Petri net (TPN) notation. Then, the problem is formalized on the basis of the established TPN, in such a way as to carry out a sound and trustworthy analysis. The various steps of the developed approach are detailed and illustrated in the course of this paper. To the best of our knowledge, this is the first work that seeks to elaborate a control strategy of automatic LC in the ERTMS operation context. Auteurs: Mohamed Ghazel; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 10.-2017, volume: 18, issue:10, pages: 2667 - 2680 Editeur: IEEE Document complet vers site de l'éditeur
» A Cooperative Operation of Novel PV Inverter Control Scheme and Storage Energy Management System Based on ANFIS for Voltage Regulation of Grid-Tied PV System
 Résumé:In this paper, the voltage regulation problem in low-voltage power distribution networks integrated with increased amount of solar photovoltaics (PV) has been addressed. This paper proposes and evaluates the cooperative performance of a novel proportional-integral-derivative (PID) control scheme for PV interfacing inverter based on intelligent adaptive neuro-fuzzy inference system (ANFIS) and an ANFIS-based supervisory storage energy management system (EMS) for regulating the voltage of three-phase grid-connected solar PV system under any nonlinear and fluctuating operating conditions. The proposed ANFIS-based PID control scheme (ANFISPID) dynamically controls the PV inverter to inject/ absorb appropriate reactive power to regulate the voltage at point of common coupling (PCC) and provides robust response at any system worst case scenarios and grid faults. And the proposed ANFIS-based supervisory EMS controls the charge/discharge of the energy storage system when there is voltage deviation to cooperate with ANFISPID in PCC voltage regulation. The proposed ANFISPID-based PV inverter control scheme and ANFIS-based supervisory EMS are developed and simulated in MATLAB/ Simulink environment and their dynamic cooperative performances are compared with cooperative performances of conventional PID-based PV inverter control scheme and state-based EMS. Auteurs: Nasif Mahmud;Ahmad Zahedi;Asif Mahmud; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2657 - 2668 Editeur: IEEE Document complet vers site de l'éditeur
» A Coupling Between the Facet Finite Element and Reluctance Network Methods in 3-D
 Résumé:A 3-D finite-element method mesh is converted to a reluctance network through an original magnetostatic formulation based on facet shape functions interpolation of the magnetic induction. This network is coupled with a standard reluctance network, characterizing a 0-D system and solved by a circuit solver approach. Auteurs: Anderson S. Nunes;Olivier Chadebec;Patrick Kuo-Peng;Patrick Dular;Gerard Meunier; Apparue dans: IEEE Transactions on Magnetics Date publication: 10.-2017, volume: 53, issue:10, pages: 1 - 10 Editeur: IEEE Document complet vers site de l'éditeur
» A Current-Dependent Switching Strategy for Si/SiC Hybrid Switch-Based Power Converters
 Résumé:Hybrid switches configured by paralleling Silicon (Si) Insulated Gate Bipolar Transistors (IGBT) and Silicon Carbide (SiC) Metal-Oxide Semiconductor Field-Effect Transistors (MOSFET) have been verified to be a high-efficiency cost-effective device concept. In this paper, a current-dependent switching strategy is introduced and implemented to further improve the performance of Si/SiC hybrid switches. This proposed switching strategy is based on a comprehensive consideration of reducing device losses, reliable operation, and overload capability. Based on the utilization of such Si/SiC hybrid switches and the proposed switching strategy, a 15-kW single-phase H-bridge inverter prototype was implemented and tested in the laboratory. Simulation and experimental results are given to verify the performance of the hybrid switches and the new switching strategy. Auteurs: Jiangbiao He;Ramin Katebi;Nathan Weise; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 8344 - 8352 Editeur: IEEE Document complet vers site de l'éditeur
» A DAC With an Impedance Attenuator and Distortion Analysis Using Volterra Series
 Résumé:An impedance attenuator is implemented to reduce digital-to-analog converter (DAC) distortion, and two techniques to further reduce the distortion are discussed: the first is to use cross-coupled capacitors to cancel nonlinear currents; the second is to optimize the common-mode bandwidth of the differential amplifier for cancellation of distortion. To support these techniques, DAC distortion has been analyzed with the Volterra series, and the analysis is compared with simulation results and measurement data. The analysis uncovers a previously unknown nonlinear cancellation mechanism for the DAC and confirms the proposed techniques. Each technique can contribute 3–6 dB of improvement, and about a 6-dB improvement when combined. The 0.708-mm2 DAC is fabricated in a 28-nm metal-gate digital CMOS process with the proposed impedance attenuator, and it achieves −89 dBc of average HD3 at a 5-MHz input frequency and sampling rate of 230.4 MHz. Auteurs: Sang Min Lee;Namsoo Kim;Derui Kong;Dongwon Seo; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2929 - 2938 Editeur: IEEE Document complet vers site de l'éditeur
» A Decoupled Adaptive Noise Detection Based Control Approach for a Grid Supportive SPV System
 Résumé:A grid supportive two-stage three-phase four-wire solar photovoltaic (SPV) system is presented in this paper, wherein a boost converter is used as a first stage to serve the function of maximum power point tracking (MPPT) and a four-leg voltage source converter (VSC) is used to feed the extracted SPV energy, along with supporting distribution system for improvement in the power quality. Unlike conventional SPV inverters, the proposed solar energy conversion system provides extra functionalities such as balancing of grid currents, reactive power compensation, mitigation of harmonics, and neutral current elimination in grid side neutral conductor. An extra feed-forward term is added in the control loop to provide fast dynamic responses. The PV array voltage is continuously adjusted using a boost converter to achieve MPPT. A control approach employing decoupled adaptive noise detection (DAND) algorithm is used for controlling the four-leg grid-tied VSC. The DAND algorithm is a simple approach using two multipliers, one integrator, and one summer per phase for detection of useful component of load current. The proposed control algorithm gives features such as simple structure, fast convergence, frequency adaptive detection, and good steady-state performance. The grid currents are found adhering to an IEEE-519 standard, even under nonlinear and unbalanced loads at common point of interconnection. Auteurs: Bhim Singh;Chinmay Jain; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4894 - 4902 Editeur: IEEE Document complet vers site de l'éditeur
» A Descriptor Approach to Robust Leader-Following Output Consensus of Uncertain Multi-Agent Systems With Delay
 Résumé:In this technical note, a descriptor approach to leader-following output consensus of multi-agent systems with both stationary and dynamic leaders is given in the presence of transmission delay and model uncertainty. The proposed method can deal with stable and unstable agents described by general linear models. To this end, a new proportional-derivative-integral (PID) consensus protocol for the closed-loop multi-agent system is proposed under a directed graph. Applying this consensus protocol to the multi-agent system leads to a time-delay closed-loop equation of neutral type. To deal with the resulting neutral system, a descriptor model transformation is used to derive delay-dependent sufficient conditions for the existence of the consensus protocol in terms of certain linear matrix inequalities (LMI). The application of the proposed method is illustrated in a teleoperation system. Simulation results are given to show the effectiveness of the proposed approach. Auteurs: Ala Shariati;Mahdi Tavakoli; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5310 - 5317 Editeur: IEEE Document complet vers site de l'éditeur
» A Differential Electrochemical Readout ASIC With Heterogeneous Integration of Bio-Nano Sensors for Amperometric Sensing
 Résumé:A monolithic biosensing platform is presented for miniaturized amperometric electrochemical sensing in CMOS. The system consists of a fully integrated current readout circuit for differential current measurement as well as on-die sensors developed by growing platinum nanostructures (Pt-nanoS) on top of electrodes implemented with the top metal layer. The circuit is based on the switch–capacitor technique and includes pseudodifferential integrators for concurrent sampling of the differential sensor currents. The circuit further includes a differential to single converter and a programmable gain amplifier prior to an ADC. The system is fabricated in $\text{0.35}\ \mu \text{m}$ technology and measures current within $\pm \text{20}\ \mu \text{A}$ with minimum input-referred noise of $\text{0.47}\ \text{pA}$ and consumes $\text{9.3}\ \text{mW}$ from a $\text{3.3}\ \text{V}$ supply. Differential sensing for nanostructured sensors is proposed to build highly sensitive and offset-free sensors for metabolite detection. This is successfully tested for bio-nano-sensors for the measurement of glucose in submilli molar concentrations with the proposed readout IC. The on-die electrodes are nanostructured and cyclic voltammetry run successfully through the readout IC to demonstrate detection of $\text{H}_2\text{O}_2$. Auteurs: Sara S. Ghoreishizadeh;Irene Taurino;Giovanni De Micheli;Sandro Carrara;Pantelis Georgiou; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 10.-2017, volume: 11, issue:5, pages: 1148 - 1159 Editeur: IEEE Document complet vers site de l'éditeur
» A Digitally Dynamic Power Supply Technique for 16-Channel 12 V-Tolerant Stimulator Realized in a 0.18- μm 1.8-V/3.3-V Low-Voltage CMOS Process
 Résumé:A new digitally dynamic power supply technique for 16-channel 12-V-tolerant stimulator is proposed and realized in a 0.18-μm 1.8-V/3.3-V CMOS process. The proposed stimulator uses four stacked transistors as the pull-down switch and pull-up switch to withstand 4 times the nominal supply voltage (4 × V DD). With the dc input voltage of 3.3 V, the regulated three-stage charge pump, which is capable of providing 11.3-V voltage at 3-mA loading current, achieves dc conversion efficiency of up to 69% with 400-pF integrated capacitance. Power consumption is reduced by implementing the regulated charge pump to provide a dynamic dc output voltage with a 0.5-V step. The proposed digitally dynamic power supply technique, which is implemented by using a p-type metal oxide semiconductor (PMOS) inverter with pull-down current source and digital controller, greatly improves the power efficiency of a system. The silicon area of the stimulator is approximately 3.5 mm2 for a 16-channel implementation. The functionalities of the proposed stimulator have been successfully verified through animal test. Auteurs: Zhicong Luo;Ming-Dou Ker;Tzu-Yi Yang;Wan-Hsueh Cheng; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 10.-2017, volume: 11, issue:5, pages: 1087 - 1096 Editeur: IEEE Document complet vers site de l'éditeur
» A Double-T-Type Compensation Network and Its Tuning Method for IPT System
 Résumé:This paper presents a new design strategy for an S-LCC-type compensation network in inductive power transfer (IPT) systems to achieve constant voltage output. It was found that four resonant elements (three capacitors and one inductor) can compose two symmetric T-type resonant tanks, which is well-known for its impedance transformation characteristic and reciprocity between voltage source and current source. A simplified analytical technique is used to calculate the voltage gain and parameters for each resonant element. Besides, the proposed tuning method for an S-LCC network has negligible response to high-order harmonics, allowing wide range of output voltage regulation and easy implementation of zero voltage switching. To aid designers in practical design and circuit debugging, sensitivity of one critical resonant element is analyzed. To verify the analysis, a 165 W prototype with 50 mm gap and fixed voltage transfer ratio was fabricated and tested. An overall 90% efficiency was achieved from dc 70 V input to dc 30 V output. Auteurs: Yijie Wang;Guangyao Shi;Yousu Yao;Jose Marcos Alonso;Guo Weifeng;Xiaosheng Liu;Dianguo Xu; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4757 - 4767 Editeur: IEEE Document complet vers site de l'éditeur
» A DSE-Based Power System Frequency Restoration Strategy for PV-Integrated Power Systems Considering Solar Irradiance Variations
 Résumé:With power networks undergoing an unprecedented transition from traditional power systems to modern electric grids integrated with renewable energy sources, maintaining frequency stability of generators in modern power systems has become one of the major concerns. Targeting this issue, in this paper, we propose a novel frequency restoration strategy in photovoltaics (PV)-connected power systems using decentralized dynamic state estimation technique and PV power plant as a contingency power source. When a sudden increase in load demand occurs, the output power of PV panels is increased in order to compensate for the shortage of real power capacity of the generator, in order to restore the frequency of a certain generator bus bar. An unscented Kalman filter-based decentralized dynamic estimation is utilized in this study to estimate the frequency of a selected generator bus bar with local noisy voltage and current measurement data acquired by using phasor measurement units. Solar luminous intensity may vary over a period of time in different seasons, weather conditions, etc., which causes the variations in the output power of PV power plants. This irradiance uncertainty is also considered in this study. The proposed control strategy not only incorporates the frequency deviations of a generator bus-bar, but also takes into account the tie-line power deviations under disturbances. Simulation results demonstrate the capacity of proposed control schemes in restoring the frequency of generator bus-bars and also maintaining the tie-line power flowing between adjoining areas at it scheduled value. Auteurs: Shenglong Yu;Lijun Zhang;Herbert Ho-Ching Iu;Tyrone Fernando;Kit Po Wong; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2511 - 2518 Editeur: IEEE Document complet vers site de l'éditeur
» A Dual-Band 1:10 Wilkinson Power Divider Based on Multi-T-Section Characterization of High-Impedance Transmission Lines
 Résumé:We propose a new methodology for the design of a dual-band unequal-split Wilkinson power divider (WPD) with a high power division ratio at the operating frequencies. Impractical high-impedance transmission line in the conventional divider is replaced with cascaded dual-band T-section structures based on analytical equations derived herein. To validate the design concept, a dual-band WPD operating at 1 and 2 GHz with a 1:10 split ratio is simulated and measured. Simulations and measurements show isolation and input–output ports matching better than −20 dB, and transmission parameters, $S_{21}$ and $S_{31}$ , of −10.5 ± 0.5 dB and −0.4 ± 0.5 dB at the design bands, respectively. Auteurs: Khair Al Shamaileh;Nihad Dib;Said Abushamleh; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 897 - 899 Editeur: IEEE Document complet vers site de l'éditeur
» A Dual-Polarized Pattern Reconfigurable Yagi Patch Antenna for Microbase Stations
 Résumé:A two-port pattern reconfigurable three-layered Yagi-Uda patch antenna with ±45° dual-polarization characteristic is presented. A driven patch (DP) and two large parasitic patches (LPPs) are printed on the top side of the middle layer, and the middle and bottom layers share a common metal ground. Two microstrip feedlines printed orthogonally on the bottom side of the bottom layer are used to feed the DP through two H-shaped slots etched in the ground. The LPPs are connected to/disconnected from the ground controlled by switches. By adjusting the connection states of the LPPs, one wide-beam mode and three narrow-beam modes can be obtained in both polarizations. A small parasitic patch is printed on the top side of the top layer to improve the pattern coherence of the two polarizations. This antenna is studied by both simulation and measurement. The measured common bandwidth of the four modes in both polarizations is 3.32–3.51 GHz, and the isolations between two polarizations in all the modes are higher than 20 dB. The low-profile antenna is very suitable for microbase-station applications. Auteurs: Wan-Qiang Deng;Xue-Song Yang;Cong-Song Shen;Jianping Zhao;Bing-Zhong Wang; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5095 - 5102 Editeur: IEEE Document complet vers site de l'éditeur
» A Facile Approach to Fabricate Patterned Surfaces for Enhancing Light Efficiency of COB-LEDs
 Résumé:Light efficiency of chip-on-board light-emitting diodes (COB-LEDs) is much lower than the single-chip packaging LEDs due to its flat phosphor layer, and hemispherical phosphor layer realization is a great challenge in COB-LEDs packaging due to the low surface tension of the phosphor gel. In this paper, we demonstrated a facile method to fabricate patterned surfaces to deal with this challenge. First, nanosilica (NS) particles with average diameter of 70 nm were fabricated by hydrolyzing the tetraethoxysilane and further modified by 1H,1H,2H,2H-perfluorooctyl-trichlorosilane, then patterned surfaces were fabricated by introducing a tailored template into the NS coating process. The results show that the NS coated surfaces display repellency to the water and phosphor gel with porous lotus leaf-like hierarchical structure, when the particle deposition density (PDD) of the NS particles increases from 0 to 6 g/m2, the contact angle (CA) of water increases from 34° to 161°, and the CA of phosphor gel increases from 22° to 145°. Hemispherical phosphor layer was achieved with the patterned surfaces when the PDD is 1.5 g/m2. Compared to the conventional flat phosphor layer, the hemispherical phosphor layer enhances the light efficiency by 11.74% and 14.52% for 4000 and 5000 K COB-LEDs. Auteurs: Xingjian Yu;Bin Xie;Bofeng Shang;Weicheng Shu;Xiaobing Luo; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4149 - 4155 Editeur: IEEE Document complet vers site de l'éditeur
» A Fast Image Retrieval Method Designed for Network Big Data
 Résumé:In the field of big data applications, image information is widely used. The value density of information utilization in big data is very low, and how to extract useful information quickly is very important. So we should transform the unstructured image data source into a form that can be analyzed. In this paper, we proposed a fast image retrieval method which designed for big data. First of all, the feature extraction method is necessary and the feature vectors can be obtained for every image. Then, it is the most important step for us to encode the image feature vectors and make them into database, which can optimize the feature structure. Finally, the corresponding similarity matching is used to determined the retrieval results. There are three main contributions for image retrieval in this paper. New feature extraction method, reasonable elements ranking, and appropriate distance metric can improve the algorithm performance. Experiments show that our method has a great improvement in the effective performance of feature extraction and can also get better search matching results. Auteurs: Jiachen Yang;Bin Jiang;Baihua Li;Kun Tian;Zhihan Lv; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2350 - 2359 Editeur: IEEE Document complet vers site de l'éditeur
» A Fast Method for Modeling Skew and Its Effects in Salient-Pole Synchronous Generators
 Résumé:The general effects of implementing skewing techniques in electrical machines are well known and have been extensively studied over the years. An important aspect of such techniques is related to the identification of optimal methods for analyzing and modeling any skewed components. This paper presents a fast, finite-element-based method, able to accurately analyze the effects of skew on wound-field, salient-pole synchronous generators in a relatively shorter time than the more traditional methods. As a vessel for studying the proposed technique, a 400 kVA alternator is considered. Analytical and theoretical considerations on the benefits of skewing the stator in the generator under analysis are preliminary carried out. A finite-element model of the machine is built and the proposed method is then implemented to investigate the effects of the skewed stator. Comparisons against more traditional techniques are presented, with focus on the analysis of the voltage total harmonic distortion and the damper bars' currents. Finally, experimental tests are performed at no-load and on-load operations for validation purposes, with excellent results being achieved. Auteurs: Stefano Nuzzo;Michael Galea;Chris Gerada;Neil Brown; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 10.-2017, volume: 64, issue:10, pages: 7679 - 7688 Editeur: IEEE Document complet vers site de l'éditeur
» A First Insight to the Thermal Dependence of the DC, Analog and RF Performance of an S/D Spacer Engineered DG-Ambipolar FET
 Résumé:This paper investigates for the first time the temperature dependence of the digital/analog parameters and RF figure of merits (FOMs) of a spacer based reconfigurable field-effect transistor (RFET) and compares the same with the existing RFET topology and other devices which depend on band-to-band tunneling (BTBT) for their on-current generation. It is observed that the output characteristics of the device are less sensitive to the temperature in the BTBT dominated on-state region as compared to the subthreshold one which is thermionic emission dependent. Having a better thermal stability over tunnel field effect transistor (TFET) and significantly lesser Vth roll-off, the proposed device portrays orders of magnitude reduction in parasitic gate capacitances and intrinsic delay as compared to gate-all-around (GAA) and hetero gate dielectric GAA TFET devices over the considered range of temperature, thus assuring higher switching speed for digital applications. Moreover, superior analog/RF performance is also exhibited by the device under consideration for all temperatures in contrast to SiGe, full silicon TFETs, and conventional RFET topology owing to higher BTBT dominance and better gate controllability. Apart from all of these performance gains, the device FOMs are found to be less sensitive to temperature variations making it more suitable for applications where temperature fluctuation is a major concern. Auteurs: Abhishek Bhattacharjee;Marampally Saikiran;Sudeb Dasgupta; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4327 - 4334 Editeur: IEEE Document complet vers site de l'éditeur
» A Flexible Capacitive Pressure Sensor for Wearable Respiration Monitoring System
 Résumé:This paper presents the design, fabrication, and characterization of a wearable capacitive pressure sensor for respiration-monitoring systems. For the dielectric layer of the proposed capacitive sensor, Porous Ecoflex with a porosity of ~36% was prepared from a manually made sugar cube via a simple melting process. A polydimethylsiloxane-based silver nanowire and carbon fibers thin films were used for the sensor electrodes. The fabricated flexible pressure sensor exhibited a high sensitivity of 0.161 kPa−1 for low pressure regime (<10 kPa), a wide working pressure range of <200 kPa, and a high durability over 6000 cycles. Since the proposed sensor is flexible and resizable, it can be integrated into clothes and easily placed at any location of the human body. Finally, the practicality of the sensor was successfully demonstrated by integrating the sensor into a waist belt to monitor the real-time respiration signal of the human being. The finding is highly useful to monitor respiration signal for the detection of diseases, such as sleep apnea, asthma, and others. Auteurs: Seong Won Park;Partha Sarati Das;Ashok Chhetry;Jae Yeong Park; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6558 - 6564 Editeur: IEEE Document complet vers site de l'éditeur
» A Flexible Divide-and-Conquer MPSoC Architecture for MIMO Interference Cancellation
 Résumé:The fast-evolving standards of the wireless communication systems drive the demand for flexible baseband processing platforms. However, with the proliferation of MIMO technologies, traditional single-core-based solutions are hardly able to fulfill requirements with acceptable power and area cost. The reliance on multi-/many-core system is increasing. Different from the computation-limited single-core-based solutions, multi-/many-core systems are often communication-limited. In this paper, aiming at MIMO interference cancellation algorithms, we propose a flexible master–slave-based multiprocessor system-on-chiparchitecture based on a systematically divide-and-conquer approach to optimize the communication problems from the application-, architecture- and programming-levels. First, a comprehensively analysis of several typical applications in terms of parallelism, communication patterns and computation patterns is presented. According to the analysis results, a low-complexity and flexible ad hoc point-to-point interconnected fine-grained programmable-element ( $f$ -PE) is proposed to execute the arithmetic calculation. In order to reduce the communicationtraffic, an $f$ -PE-based slave-node is constructed to exploit the data and instruction localities of applications, and a master node that is used to schedule and serve data for the slave nodes is also integrated. Furthermore, to improve the ease of use of the architecture, a multiple instruction multiple datalikeprogramming model is adopted and an optimizing mapping strategy is developed. In order to show its flexibility potential, seven linear and nonlinear IC algorithms with distinct computation natures are implemented on the proposed architecture. Finally, the gate-level synthesis and postlayout results are presented to demonstrate the strength and weakn- sses of our design. Auteurs: Luechao Yuan;Cang Liu;Chuan Tang;Shan Huang;Anupam Chattopadhyay;Gerd Ascheid;Zuocheng Xing; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 10.-2017, volume: 25, issue:10, pages: 2789 - 2802 Editeur: IEEE Document complet vers site de l'éditeur
» A Flexible Foldable Tubular μDMFC for Powering Wearable Devices
 Résumé:This paper demonstrates a flexible tubular passive micro direct methanol fuel cell ( $\mu$ DMFC) featured by flexible electrodes and foldable whole structure for powering wrist bands the first time. A novel foldable structure, its fabrication, and assembly method proposed are usable for the flexible tubular $\mu$ DMFCs and even other multi-layer flexible microfluidic devices. The test results show that the prototype achieves a power density of 15.3 mWcm−2 and a maximum output of 38 mW at room temperature. After 100 bending cycles (180 bending angle), the performance of the $\mu$ DMFC decreases about 7.8%. Furthermore, the assembled $\mu$ DMFC with a dc-dc converter is integrated into a wrist band to power an LED and dc motor (25 mW) for about 21 h with consumption of 1-mL methanol solution (50 wt%). It is believed that this $\mu$ DMFC is applicable to serve as the power unit for wrist bands (typically 1~20 mW) or even other wearable devices. [2016-0142] Auteurs: Zonglin Wu;Xuanlin Kuang;Litian Liu;Xiaohong Wang; Apparue dans: Journal of Microelectromechanical Systems Date publication: 10.-2017, volume: 26, issue:5, pages: 1147 - 1154 Editeur: IEEE Document complet vers site de l'éditeur
» A Flexible, General-Purpose Code Based on the Iterative Physical Optics Algorithm: Analyzing Electromagnetic Scattering in Electrically Large Scenarios. [EM Programmer's Notebook]
 Résumé:A very flexible and efficient iterative physical optics (IPO) algorithm is presented for analyzing the electromagnetic (EM) scattering of complex and electrically large problems. The algorithm accounts for multiple interactions between the objects comprised in the scenarios under the physical optics (PO) approximation. Various techniques for accelerating and parallelizing the algorithm were used, thus obtaining an efficient tool that can be used in novel high-frequency solvers. Auteurs: Luca Pandolfo;Paolo De Vita;Mauro Bandinelli;Giorgio Carluccio;Matteo Albani; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 10.-2017, volume: 59, issue:5, pages: 150 - 158 Editeur: IEEE Document complet vers site de l'éditeur
» A Frequency Correcting Method Combining Bilateral Correction With Weighted Average for Vortex Flow Sensor Signal
 Résumé:The sinusoidal signal outputted by the vortex flow sensor is often superimposed with the white noise, which will affect the accuracy of spectrum correction. When the signal is truncated by rectangular window, a method (hereinafter referred to as RWBWFCR) combining bilateral correction with weighted average on the basis of Fourier coefficients ratio is proposed so as to improve the antinoise performance of the frequency correction. The correction principle of this method is presented. The effects on the frequency correction of changing the initial phase, the frequency deviation, the calculation points of fast Fourier transform, and the signal-to-noise ratio (SNR) are analyzed. The theoretical accuracy of this method when there is stationary Gaussian white noise is deduced and verified. This method has some advantages, such as less computation load, small storage space, high correction precision, strong anti-interference ability, and is easy to be implemented by a microcontroller in real time. RWBWFCR method is applied to the low-power and antivibration type vortex flowmeter with single sensor to improve the reliability of the digital signal processing method based on the frequency correction. Auteurs: Chun-Li Shao;Ke-Jun Xu;Zhang-Ping Shu;Ao Li; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2711 - 2724 Editeur: IEEE Document complet vers site de l'éditeur
» A General Analytical Three-Phase Induction Machine Core Loss Model in the Arbitrary Reference Frame
 Résumé:An analytical three-phase induction machine model is proposed, derived, and validated in this paper. This model is capable for arbitrary qd0-frame analysis and core loss estimation at both line-fed and inverter-fed situations. Detailed model-based machine copper and core loss estimations are presented. A simulation verification of the model consistency is given under a changing load profile in MATLAB/Simulink. Then, the model is verified comprehensively using three induction machines (1.5 HP, 3 HP, and 10 HP), where the model is proved to be scalable, and to provide excellent machine loss estimation in line-fed situation and inverter-fed situation with machine input line filters, as well as in the flux-weakening region. Finally, a series of sensitivity tests of the model parameters are performed and the effects of the parameters on the machine losses are discussed. It is believed that the proposed model will be beneficial for various qd0-frame model-based research works of three-phase induction machines. Auteurs: Yiqi Liu;Ali M. Bazzi; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4210 - 4220 Editeur: IEEE Document complet vers site de l'éditeur
» A General Framework for Hardware Trojan Detection in Digital Circuits by Statistical Learning Algorithms
 Résumé:The continuous globalization of the semiconductor industry has significantly raised the vulnerability of chips under hardware Trojan (HT) attacks. It is extremely challenging to detect HTs in fabricated chips due to the existence of process variations (PVs), since PVs may cause larger impacts than HTs. In this paper, we propose a novel framework for HT detection in digital integrated circuits. The goal of this paper is to detect HTs inserted during fabrication. The HT detection problem is formulated as an under-determined linear system by a sparse gate profiling technique, and the existence of HTs is mapped to the sparse solution of the linear system. A Bayesian inference-based calibration technique is proposed to recover PVs for each chip for the sparse gate profiling technique. A batch of under-determined linear systems are solved together by the well-studied simultaneous orthogonal matching pursuit algorithm to get their common sparse solution. Experimental results show that even under big measurement errors, the proposed framework gets quite high HT detection rates with low measurement cost. Auteurs: Xiaoming Chen;Lin Wang;Yu Wang;Yongpan Liu;Huazhong Yang; Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Date publication: 10.-2017, volume: 36, issue:10, pages: 1633 - 1646 Editeur: IEEE Document complet vers site de l'éditeur
» A General Noise-Resilient Technique Based on the Matrix Pencil Method for the Assessment of Harmonics and Interharmonics in Power Systems
 Résumé:This paper presents a high-accuracy technique for the assessment of harmonics and interharmonics in power systems. In the proposed method, a generalized eigenvalue problem is solved by making use of the matrix pencil method. It is a general method in the sense that it has the ability to predict the frequency, amplitude, and relative phase of frequency components present in a given signal, while the dc-off set and damping factors can be accurately estimated. It also offers a noise-resilient feature which helps to efficiently analyze the noise-contaminated signals. It shows a good performance in dealing with modulated signals as well. Due to its excellent accuracy, the proposed method is foreseen to properly work for the estimation of phasors which is a crucial need in the electrical networks. Different simulation and experimental cases are presented to evaluate the efficiency of the proposed method. Auteurs: Keyhan Sheshyekani;Ghasem Fallahi;Mohsen Hamzeh;Morteza Kheradmandi; Apparue dans: IEEE Transactions on Power Delivery Date publication: 10.-2017, volume: 32, issue:5, pages: 2179 - 2188 Editeur: IEEE Document complet vers site de l'éditeur
» A General-Purpose Architecture for Replicated Metadata Services in Distributed File Systems
 Résumé:A large class of modern distributed file systems treat metadata services as an independent system component, separately from data servers. The availability of the metadata service is key to the availability of the overall system. Given the high rates of failures observed in large-scale data centers, distributed file systems usually incorporate high-availability (HA) features. A typical approach in the development of distributed file systems is to design and develop metadata services from the ground up, at significant cost in terms of complexity and time, often leading to functional shortcomings. Our motivation in this paper was to improve on this state of things by defining a general-purpose architecture for HA metadata services (which we call RMS) that can be easily incorporated and reused in new or existing file systems, reducing development time. Taking two prominent distributed file systems as case studies, PVFS and HDFS, we developed RMS variants that improve on functional shortcomings of the original HA solutions, while being easy to build and test. Our extensive evaluation of the RMS variant of HDFS shows that it does not incur an overall performance or availability penalty compared to the original implementation. Auteurs: Dimokritos Stamatakis;Nikos Tsikoudis;Eirini Micheli;Kostas Magoutis; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 10.-2017, volume: 28, issue:10, pages: 2747 - 2759 Editeur: IEEE Document complet vers site de l'éditeur
» A Generalized Reduced Gradient Method for the Optimal Control of Very-Large-Scale Robotic Systems
 Résumé:This paper develops a new indirect method for distributed optimal control (DOC) that is applicable to optimal planning for very-large-scale robotic (VLSR) systems in complex environments. The method is inspired by the nested analysis and design method known as generalized reduced gradient (GRG). The computational complexity analysis presented in this paper shows that the GRG method is significantly more efficient than classical optimal control or direct DOC methods. The GRG method is demonstrated for VLSR path planning in obstacle-populated environments in which robots are subject to external forces and disturbances. The results show that the method significantly improves performance compared to the existing direct DOC and stochastic gradient methods. Auteurs: Keith Rudd;Greg Foderaro;Pingping Zhu;Silvia Ferrari; Apparue dans: IEEE Transactions on Robotics Date publication: 10.-2017, volume: 33, issue:5, pages: 1226 - 1232 Editeur: IEEE Document complet vers site de l'éditeur
» A Generic Level 1 Simulator for Spaceborne GNSS-R Missions and Application to GEROS-ISS Ocean Reflectometry
 Résumé:In the past decade Global Navigation Satellites System Reflectometry (GNSS-R) has emerged as a new technique for earth remote sensing for various applications, such as ocean altimetry and sea state monitoring. After the success of the GNSS-R demonstrator payloads aboard the UK-DMC or TDS-1 satellites; at present, there are several missions planned to carry GNSS reflectometers. The GNSS rEflectometry, Radio Occultation, and Scatterometry onboard International Space Station (GEROS-ISS) is an innovative ISS experiment exploiting GNSS-R technique to measure key parameters of ocean, land, and ice surfaces. For GEROS-ISS mission, the European Space Agency (ESA) supported the study of GNSS-R assessment of requirements and consolidation of retrieval algorithms (GARCA). For this, it was required to accurately simulate the GEROS-ISS measurements including the whole range of parameters affecting the observation conditions and the instrument, which is called GEROS-SIM. To meet these requirements, the PAU/PARIS end-to-end performance simulator (P$^{2}$EPS) previously developed by UPC BarcelonaTech was used as the baseline building blocks for the level 1 (L1) processor of GEROS-SIM. P $^{2}$EPS is a flexible tool, and is capable of systematically simulating the GNSS-R observations for spaceborne GNSS-R missions. Thanks to the completeness and flexibility, the instrument-to-L1 data module of GEROS-SIM could be implemented by proper modification and update of P $^{2}$EPS. The developed GEROS-SIM was verified and validated in the GARCA study as comparing to the TDS-1 measurements. This paper presents the design, implementation, and results of the GEROS-SIM L1 module in a generic way to be applied to GNSS-R instruments. Auteurs: Hyuk Park;Adriano Camps;Daniel Pascual;Yujin Kang;Raul Onrubia;Jorge Querol;Alberto Alonso-Arroyo; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4645 - 4659 Editeur: IEEE Document complet vers site de l'éditeur
» A Generic Simulation Approach for the Fast and Accurate Estimation of the Outage Probability of Single Hop and Multihop FSO Links Subject to Generalized Pointing Errors
 Résumé:When assessing the performance of the free space optical (FSO) communication systems, the outage probability encountered is generally very small, and thereby the use of nave Monte Carlo simulations becomes prohibitively expensive. To estimate these rare event probabilities, we propose in this paper an importance sampling approach which is based on the exponential twisting technique to offer fast and accurate results. In fact, we consider a variety of turbulence regimes, and we investigate the outage probability of FSO communication systems, under a generalized pointing error model based on the Beckmann distribution, for both single and multihop scenarios. Selected numerical simulations are presented to show the accuracy and the efficiency of our approach compared with naive Monte Carlo. Auteurs: Chaouki Ben Issaid;Ki-Hong Park;Mohamed-Slim Alouini; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6822 - 6837 Editeur: IEEE Document complet vers site de l'éditeur
» A Geometrical View of Scalar Modulation Instability in Optical Fibers
 Résumé:Full models of scalar modulation instability (MI) in optical fibers available in the literature usually involve complex formulations. In this paper, we present a novel approach to the analysis of MI in optical fibers by means of a simple geometrical description in the power versus frequency plane. This formulation allows us to relate the shape of the MI gain to any arbitrary dispersion profile of the medium, thus providing a simple insight. As a result, we derive a straightforward explanation of the nontrivial dependence of the cutoff power on high-order dispersion and explicitly derive the power that maximizes the gain. Our approach puts forth a tool to synthesize a desired MI gain with the potential application to a number of parametric-amplification and supercontinuum-generation devices whose initial-stage dynamics rely upon MI. Auteurs: S. M. Hernandez;P. I. Fierens;J. Bonetti;A. D. Sánchez;D. F. Grosz; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 8 Editeur: IEEE Document complet vers site de l'éditeur
» A GPU-Accelerated Approach for Feature Tracking in Time-Varying Imagery Datasets
 Résumé:We propose a novel parallel connected component labeling (CCL) algorithm along with efficient out-of-core data management to detect and track feature regions of large time-varying imagery datasets. Our approach contributes to the big data field with parallel algorithms tailored for GPU architectures. We remove the data dependency between frames and achieve pixel-level parallelism. Due to the large size, the entire dataset cannot fit into cached memory. Frames have to be streamed through the memory hierarchy (disk to CPU main memory and then to GPU memory), partitioned, and processed as batches, where each batch is small enough to fit into the GPU. To reconnect the feature regions that are separated due to data partitioning, we present a novel batch merging algorithm to extract the region connection information across multiple batches in a parallel fashion. The information is organized in a memory-efficient structure and supports fast indexing on the GPU. Our experiment uses a commodity workstation equipped with a single GPU. The results show that our approach can efficiently process a weather dataset composed of terabytes of time-varying radar images. The advantages of our approach are demonstrated by comparing to the performance of an efficient CPU cluster implementation which is being used by the weather scientists. Auteurs: Chao Peng;Sandip Sahani;John Rushing; Apparue dans: IEEE Transactions on Visualization and Computer Graphics Date publication: 10.-2017, volume: 23, issue:10, pages: 2262 - 2274 Editeur: IEEE Document complet vers site de l'éditeur
» A Handbag Zipper Antenna for the Applications of Body-Centric Wireless Communications and Internet of Things
 Résumé:The idea of making use of the metal zipper on the handbag to serve as an off-body antenna is proposed, and the simulations together with measurements have been carried out. The feeding point can be located at the bottom of the zipper, and to be more specific, around one of the teeth. The excitation at certain tooth of the zipper would bring variations in the reflection coefficients as well as the radiation patterns. No matter the zipper is totally closed, quarterly opened, half opened, or is even totally opened, the antenna can operate with acceptable performance, though the common status of the handbag zipper is closed. Thus, it is to some extent reconfigurable, especially for radiation patterns. A fractional bandwidth of 4.92% at 2.44 GHz of the industrial, scientific, and medical band with a gain of about 5 dBi has been achieved. The impact of the human body has been evaluated. It is noticeable but affordable. The measured results indicate reasonable agreements to that of the simulations in both the matching performance and the radiation feature for the zipper antenna, which seems to be a promising candidate for body-centric wireless communications and the Internet of Things. Auteurs: Gaosheng Li;Yi Huang;Gui Gao;Xianju Wei;Zhihao Tian;Li-An Bian; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5137 - 5146 Editeur: IEEE Document complet vers site de l'éditeur
» A Handy Dandy Doherty PA: A Linear Doherty Power Amplifier for Mobile Handset Application
 Résumé:As wireless communications progress from second to fourth-generation (4G) systems, the information content drastically increases, requiring high-data-rate transmissions. For efficient use of precious spectrum resources, the modulated signals have wider bandwidths (BWs) and higher peak-toaverage power ratios (PAPRs) than previous generations of systems. Therefore, the power amplifier (PA) operates at a less efficient backoff-power region to achieve the required linearity. Auteurs: Yunsung Cho;Daehyun Kang;Kyunghoon Moon;Daechul Jeong;Bumman Kim; Apparue dans: IEEE Microwave Magazine Date publication: 10.-2017, volume: 18, issue:6, pages: 110 - 124 Editeur: IEEE Document complet vers site de l'éditeur
» A Hidden Markov Model for Seismocardiography
 Résumé:We propose a hidden Markov model approach for processing seismocardiograms. The seismocardiogram morphology is learned using the expectation-maximization algorithm, and the state of the heart at a given time instant is estimated by the Viterbi algorithm. From the obtained Viterbi sequence, it is then straightforward to estimate instantaneous heart rate, heart rate variability measures, and cardiac time intervals (the latter requiring a small number of manual annotations). As is shown in the conducted experimental study, the presented algorithm outperforms the state-of-the-art in seismocardiogram-based heart rate and heart rate variability estimation. Moreover, the isovolumic contraction time and the left ventricular ejection time are estimated with mean absolute errors of about 5 [ms] and ${\text{9 [ms]}}$, respectively. The proposed algorithm can be applied to any set of inertial sensors; does not require access to any additional sensor modalities; does not make any assumptions on the seismocardiogram morphology; and explicitly models sensor noise and beat-to-beat variations (both in amplitude and temporal scaling) in the seismocardiogram morphology. As such, it is well suited for low-cost implementations using off-the-shelf inertial sensors and targeting, e.g., at-home medical services. Auteurs: Johan Wahlström;Isaac Skog;Peter Händel;Farzad Khosrow-khavar;Kouhyar Tavakolian;Phyllis K. Stein;Arye Nehorai; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 10.-2017, volume: 64, issue:10, pages: 2361 - 2372 Editeur: IEEE Document complet vers site de l'éditeur
» A High-Frequency High-Power Test Bench for 11 MW/595 Hz Drives With 1.25 MW Grid Capability
 Résumé:This paper presents a pumpback test bench for high-frequency high-power variable-frequency drives (VFDs) with 11 MW power rating and up to 595 Hz load frequency. A voltage combiner concept is applied to allow a high-frequency output from the two three-level neutral-point-clamped integrated gate-commutated thyristor bridges with minimum switching losses. The accordingly developed pumpback test bench applies a dc power coupling concept combined with a virtual grid concept that can achieve 11 MW test capability with only a 1.25 MW facility transformer. By applying a virtual machine concept, the pumpback test can be conducted without the need of high-frequency machines, while the circulating power losses in the pumpback loop are minimized as well. The virtual grid including the concept tradeoff, filter parameters, and modulation schemes is presented in detail. Moreover, design and installation guidelines for high-frequency components, especially the cables, are presented. The high-frequency high-power VFD and its pumpback test bench are both successfully built and experimentally validated at their rated operation points. Auteurs: Jie Shen;Stefan Schröder;Bo Qu;Yingqi Zhang;Fan Zhang;Kunlun Chen;Richard Zhang; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4744 - 4756 Editeur: IEEE Document complet vers site de l'éditeur
» A High-Speed Digital Electrical Capacitance Tomography System Combining Digital Recursive Demodulation and Parallel Capacitance Measurement
 Résumé:Two means can be used to improve the data acquisition rate of the electrical capacitance tomography (ECT) system with a fixed excitation frequency, i.e., improving the capacitance measurement speed or changing the capacitance measurement mode from serial to parallel. This paper presents a newly developed high-speed ECT system by combing digital recursive demodulation and parallel-mode capacitance measurement methods. By using the digital recursive demodulator, the time-cost for one time of capacitance measurement can be one period of the excitation sinusoid or less. By using the parallel-mode capacitance measuring unit, capacitances between the exciting electrode and all other measuring electrodes can be measured simultaneously. The data acquisition rate of the parallel-mode ECT system with a sensor of N electrodes is N-1 times of a traditional serial-mode ECT system with the same excitation frequency. When the excitation frequency is 100 kHz and 0.6 periods of data are used for signal demodulation, the data acquisition rate can reach up to 15 150 frames/s. The developed system together with a heat-resisting circular ECT sensor with 12 electrodes was used to monitor the ignition process of a cylindrical flame generated by a Bunsen burner. Experimental results show that the ECT system can locate the position and capture the dynamic process of the flame with a high temporal resolution. Auteurs: Shijie Sun;Zhang Cao;Ang Huang;Lijun Xu;Wuqiang Yang; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6690 - 6698 Editeur: IEEE Document complet vers site de l'éditeur
» A Hybrid EOF Algorithm to Improve MODIS Cyanobacteria Phycocyanin Data Quality in a Highly Turbid Lake: Bloom and Nonbloom Condition
 Résumé:Extensive monitoring of cyanobacterial blooms in lakes and reservoirs can provide important protection for drinking water sources. In most inland waterbodies, phycocyanin (PC) concentrations are the best indicator of cyanobacteria distribution. PC has a characteristic absorption peak near 620 nm; however, reflectance at this wavelength is only available from MEdium Resolution Imaging Spectrometer (MERIS) and Ocean and Land Colour Instrument (OLCI) sensors. MERIS stopped providing data after 2012 and OLCI was only recently launched (February 2016). The Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua is currently the only satellite instrument that can provide well-calibrated top-of-atmosphere radiance data over an extended number of years to the present. In this study, we develop and validate a new approach based on empirical orthogonal function (EOF) to quantify PC concentrations in a turbid inland lake (Lake Chaohu, China). Based on Rayleigh-corrected reflectance data ( $R_{{\rm{rc}}}$) at 469, 555, 645, and 859 nm, the concentrations of PC were estimated by regression of 87 concurrent MODIS-field measurements for bloom and nonbloom conditions. The validation (N = 93) showed R2 = 0.40 and unbiased RMS = 60.86%. Application of the algorithm from 2000 and 2014 showed spatial distribution patterns and seasonal changes that confirmed in situ and MERIS-based studies of floating algae mats. The spatial information on PC concentrations in Lake Chaohu had a reduced sensitivity to perturbations from thin aerosols and high sediments. This EOF approach allows us for new insights in the long-term dynamics of shallow lakes and reservoirs where having a better understanding of cyanobacterial blooms i- important. Auteurs: Min Tao;Hongtao Duan;Zhigang Cao;Steven Arthur Loiselle;Ronghua Ma; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 10.-2017, volume: 10, issue:10, pages: 4430 - 4444 Editeur: IEEE Document complet vers site de l'éditeur
» A Hybrid Formulation of a Frequency-Domain TLM and Integral Equations Field Method
 Résumé:In many applications, heterogeneous structures are separated by some distance in a homogeneous medium. This homogenous space must be entirely meshed when volumic methods are used. This letter presents a hybrid formulation between the frequency-domain transmission line matrix (FDTLM) method and a field integral equation formulation that avoids the meshing of the homogeneous background in which complex objects are located. In addition, it prevents the use of absorbing boundary conditions. To simplify the theoretical development for the 3-D case, the problem of a rectangular waveguide with inductive objects is presented. Although invariance along the waveguide height with the fundamental mode excitation, the problem is treated by 3-D FDTLM nodes for validation. It is found that some computer cost reduction can be achieved as compared with the full meshing approach. Auteurs: Meriam Attia;Michel Ney;Taoufik Aguili; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 867 - 869 Editeur: IEEE Document complet vers site de l'éditeur
» A Hybrid Inductive-Ultrasonic Link for Wireless Power Transmission to Millimeter-Sized Biomedical Implants
 Résumé:Ultrasound has recently been utilized for efficient wireless power transmission (WPT) to biomedical implants with millimeter (mm) dimensions and below. However, the power transmission efficiency (PTE) of ultrasonic links reduces significantly in mediums with different acoustic impedances. This brief presents a hybrid inductive-ultrasonic WPT link for powering mm-sized implants that utilizes two cascaded co-optimized inductive and ultrasonic links for WPT through bone/air and tissue, respectively. The ultrasonic link is first optimized based on the implant depth ( $\boldsymbol {d_{\mathrm{ us}}}$ ) and load ( $\boldsymbol {R_{L}}$ ) to find the optimal geometries for ultrasonic transducers and operation frequency ( $\boldsymbol {f_{p}}$ ). Then, the inductive link is optimized at $\boldsymbol {f_{p}}$ to drive the transmitter (Tx) transducer. A hybrid link was optimized and measured to transfer power to a receiver (Rx) transducer with the diameter of 1.1 mm, loaded by $\boldsymbol {R_{L}}$ of 2.5 k $\boldsymbol {\Omega }$ and located at $\boldsymbol {d_{\mathrm{ us}} = 3}$ cm inside castor oil, as the tissue model. The Tx coil was placed in air and spaced from the Rx coil by 3 cm, resulting in a total powering distance ( ${d}$ ) of 6 cm. At the optimal $\boldsymbol {f_{p}}$ of 1.1 MHz, the hybrid link achieved a consid- rable measured PTE of 0.16%. Auteurs: Miao Meng;Mehdi Kiani; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 10.-2017, volume: 64, issue:10, pages: 1137 - 1141 Editeur: IEEE Document complet vers site de l'éditeur
» A Hybrid MPI-OpenMP Strategy to Speedup the Compression of Big Next-Generation Sequencing Datasets
 Résumé:DNA sequencing has moved into the realm of Big Data due to the rapid development of high-throughput, low cost Next-Generation Sequencing (NGS) technologies. Sequential data compression solutions that once were sufficient to efficiently store and distribute this information are now falling behind. In this paper we introduce phyNGSC , a hybrid MPI-OpenMP strategy to speedup the compression of big NGS data by combining the features of both distributed and shared memory architectures. Our algorithm balances work-load among processes and threads, alleviates memory latency by exploiting locality, and accelerates I/O by reducing excessive read/write operations and inter-node message exchange. To make the algorithm scalable, we introduce a novel timestamp-based file structure that allows us to write the compressed data in a distributed and non-deterministic fashion while retaining the capability of reconstructing the dataset with its original order. Our experimental results show that phyNGSC achieved compression times for big NGS datasets that were 45 to 98 percent faster than NGS-specific sequential compressors with throughputs of up to 3 GB/s. Our theoretical analysis and experimental results suggest strong scalability with some datasets yielding super-linear speedups and constant efficiency. We were able to compress 1 terabyte of data in under 8 minutes compared to more than 5 hours taken by NGS-specific compression algorithms running sequentially. Compared to other parallel solutions, phyNGSC achieved up to 6x speedups while maintaining a higher compression ratio. The code for this implementation is available at https://github.com/pcdslab/PHYNGSC. Auteurs: Sandino Vargas-Pérez;Fahad Saeed; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 10.-2017, volume: 28, issue:10, pages: 2760 - 2769 Editeur: IEEE Document complet vers site de l'éditeur
» A Hybrid Planar-Doped Potential-Well Barrier Diode for Detector Applications
 Résumé:This paper presents the principle of design and experimental demonstration of a prototype novel planar-doped potential-well barrier (PWB) diode concept that exploits the characteristics of both the PWB and planar-doped barrier (PDB) diodes. The highly doped (Be) sheet charge and potential well are inserted asymmetrically at nearly the same position within an intrinsic region to form a barrier. The hybrid device is designed so that the $\delta$ -doping is used to achieve a desirable minimum barrier height, while the active nature of charge in the potential well is used to enhance the device reverse bias performance. The diode achieved an ideality factor of 1.36 and corresponding voltage responsivity of 10900 V/W at 10 GHz. Diodes of this kind demonstrates promising RF signal detection and can be used in heterodyne applications. An estimated curvature coefficient of 21.2 $\text{V}^{-1}$ at a bias of 0.72 V and cut-off frequency of 47.4 GHz were realized. Results of simulation and experiment have shown excellent agreement and an improved asymmetric behavior in the ${I}$ – ${V}$ characteristics in comparison to an equivalent PDB diode. Auteurs: Mise Akura;Geoffrey Dunn;Mohamed Missous; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4031 - 4035 Editeur: IEEE Document complet vers site de l'éditeur
» A Jamming-Resistant Channel Hopping Scheme for Cognitive Radio Networks
 Résumé:Jamming attack is one of the major threats in cognitive radio networks (CRNs). In this paper, we propose an anti-jamming channel hopping algorithm, Tri-CH, for CRNs. Tri-CH adopts random jump pattern (i.e., hops randomly over channels) to achieve high security level and reception mode stay pattern (i.e., stays at a channel for receiving packets only) to guarantee bounded time to rendezvous. Tri-CH operates without pre-shared secrets and role pre-assignment. Hence, Tri-CH is applicable to large networks, where nodes join and leave the network frequently, and may play the sender role and the receiver role, simultaneously. According to the theoretical analysis, Tri-CH outperforms in terms of maximum time to rendezvous under jamming attacks. Auteurs: Guey-Yun Chang;Szu-Yung Wang;Yuen-Xin Liu; Apparue dans: IEEE Transactions on Wireless Communications Date publication: 10.-2017, volume: 16, issue:10, pages: 6712 - 6725 Editeur: IEEE Document complet vers site de l'éditeur
» A Large-Signal Monolayer Graphene Field-Effect Transistor Compact Model for RF-Circuit Applications
 Résumé:In this paper, we report a physics-based compact model for monolayer graphene field-effect transistors (m-GFETs) based on the 2-D Density of States of monolayer graphene and the drift-diffusion equation. Furthermore, the Ward-Dutton charge partitioning scheme has been incorporated to the model extending its capabilities to AC and transient simulations. The model has been validated through comparison with DC and RF measurements from two different long-channel m-GFET technologies. Moreover, values of parasitic elements included in the model are extracted from measurements on dedicated test structures and verified through electromagnetic simulations (EM). Finally, an EM-SPICE co-simulation has been carried out to assess the applicability of the developed m-GFET model for the design of “balun” circuits. Auteurs: Jorge-Daniel Aguirre-Morales;Sébastien Frégonèse;Chhandak Mukherjee;Wei Wei;Henri Happy;Cristell Maneux;Thomas Zimmer; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4302 - 4309 Editeur: IEEE Document complet vers site de l'éditeur
» A Layered Methodology for the Simulation of Extra-Functional Properties in Smart Systems
 Résumé:Smart systems represent a broad class of intelligent, miniaturized devices incorporating functionality like sensing, actuation, and control. In order to support these functions, they must include sophisticated and heterogeneous components, such as sensors and actuators, multiple power sources and storage devices, digital signal processing, and wireless connectivity. The high degree of heterogeneity typical of smart systems has a heavy impact on their design: the challenges are not in fact restricted to their functionality, but are also related to a number of extra-functional properties, including power consumption, temperature, and aging. Current simulation- or model-based design approaches do not target a smart system as a whole, but rather single domains (digital, analog, power devices, etc.) or properties. This paper tries to overcome this limitation by proposing a framework for the concurrent simulation of both functionality and such extra-functional properties. The latter are modeled as different information flows, managed by dedicated “virtual buses” and formalized through the adoption of IP-XACT. SystemC, through the support of physical and continuous time modeling provided by its analog and mixed signal extension, is used to implement both functional and extra-functional models. Experimental results show the efficiency, accuracy and modularity of the proposed approach on an example case study, in which substantial speedups with respect to standard model-based design tools go along with a very high degree of accuracy (< 10−5%). Furthermore, the case study highlights that the proposed framework allows to easily capture at run time the mutual impact of properties, e.g., in case of power and temperature. Auteurs: Sara Vinco;Yukai Chen;Franco Fummi;Enrico Macii;Massimo Poncino; Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Date publication: 10.-2017, volume: 36, issue:10, pages: 1702 - 1715 Editeur: IEEE Document complet vers site de l'éditeur
» A Liquid-Level Sensing Technique Based on Differential Detection of Correlation Peaks From Broadband Chaos
 Résumé:A highly sensitive liquid-level sensing technique is proposed and experimentally demonstrated. Two narrowband fiber Bragg gratings (FBGs) with high reflectivity are used to filter out the two light signals from the broadband chaos. Two weak FBGs are served respectively as the liquid-level sensors at two different sensing points. The change of liquid-level will induce the wavelength shift of the weak FBGs, which can be demodulated through calculating the amplitude difference in the logarithm of two cascaded correlation peaks in the cross-correlation spectrum. Adopting the differential calculation of the cascaded correlation peak amplitudes can avoid the complex wavelength detection and enhance the robustness against the power variation of the broadband chaos. Our method can also support the simultaneous multiplexing and locating with high resolution from the time delays of the corresponding correlation peaks. Experimental results show that the liquid level changes linearly with the relative peak amplitude difference in the logarithm and the sensitivity is around 0.019/mm. The sensing resolution of liquid-level can reach at least 3 mm, and the relative resolution is around 0.055. Moreover, the real-time fiber fault monitoring can be achieved with a spatial resolution of around 2.8 cm, which improves the survivability in harsh environment. Auteurs: Heng Yi;Li Xia;Jun Xu;Can Yu;Ying Wu;Chen Li;Lin Zu; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 9 Editeur: IEEE Document complet vers site de l'éditeur
» A Load Independent Tapered RF Harvester
 Résumé:This letter proposes a new matching technique that is based on a network of dual line topology with different characteristic impedances. The purpose of this network is to match the Schottky diode’s input impedance in a rectifying circuit with the 50 $\Omega$ source impedance. The strength of the proposed technique is based on the fact that it enables a stable efficiency response for different input power levels. It also forces the rectifier to exhibit an almost flat efficiency curve over a wide range of load variations. The proposed circuit is built and measured, where an agreement is attained between simulations and measured results over the IEEE 802.11 b/g bands. Auteurs: J. Costantine;A. Eid;M. Abdallah;Y. Tawk;A. H. Ramadan; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 933 - 935 Editeur: IEEE Document complet vers site de l'éditeur
» A Local Feature Descriptor Based on Log-Gabor Filters for Keypoint Matching in Multispectral Images
 Résumé:This letter presents a new local feature descriptor for problems related to multispectral images. Most previous approaches are typically based on descriptors designed to work with images uniquely captured in the visible light spectrum. In contrast, this letter proposes a descriptor termed a multispectral feature descriptor (MFD) that is especially developed, such that it can be employed with image data acquired at different frequencies across the electromagnetic spectrum. The performance of the MFD is evaluated by using three data sets composed of images obtained in visible light and infrared spectra, and its performance is compared with those of state-of-the-art algorithms, such as edge-oriented histogram (EOH) and log-Gabor histogram descriptor (LGHD). The experimental results indicate that the computational efficiency of MFD exceeds those of EOH and LGHD, and that the precision and recall values of MFD are statistically comparable to the corresponding values of the forementioned algorithms. Auteurs: Cristiano F. G. Nunes;Flávio L. C. Pádua; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 10.-2017, volume: 14, issue:10, pages: 1850 - 1854 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Complexity Maximum-Likelihood Detector for Differential Media-Based Modulation
 Résumé:Media-based modulation (MBM) uses radio frequency mirrors at the transmit antenna in order to create different channel fade realizations based on their ON/OFF status. These complex fade realizations constitute the channel modulation alphabet. This channel modulation alphabet has to be estimated a priori at the receiver for detection. In this letter, we present a differential MBM (DMBM) scheme which does not require estimation of channel modulation alphabet at the receiver for detection. Consecutive MBM blocks are differentially encoded. We propose a low-complexity maximum-likelihood detection algorithm for DMBM. Simulation results show that the DMBM has only about 2–4 dB performance loss compared with MBM with perfect knowledge of the channel alphabet. Auteurs: Y. Naresh;A. Chockalingam; Apparue dans: IEEE Communications Letters Date publication: 10.-2017, volume: 21, issue:10, pages: 2158 - 2161 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Complexity Pedestrian Detection Framework for Smart Video Surveillance Systems
 Résumé:Pedestrian detection is a key problem in computer vision and is currently addressed with increasingly complex solutions involving compute-intensive features and classification schemes. In this scope, histogram of oriented gradients (HOG) in conjunction with linear support vector machine (SVM) classifier is considered to be the single most discriminative feature that has been adopted as a stand-alone detector as well as a key instrument in advance systems involving hybrid features and cascaded detectors. In this paper, we propose a pedestrian detection framework that is computationally less expensive as well as more accurate than HOG-linear SVM. The proposed scheme exploits the discriminating power of the locally significant gradients in building orientation histograms without involving complex floating point operations while computing the feature. The integer-only feature allows the use of powerful histogram inter-section kernel SVM classifier in a fast lookup-table-based implementation. Resultantly, the proposed framework achieves at least 3% more accurate detection results than HOG on standard data sets while being 1.8 and 2.6 times faster on conventional desktop PC and embedded ARM platforms, respectively, for a single scale pedestrian detection on VGA resolution video. In addition, hardware implementation on Altera Cyclone IV field-programmable gate array results in more than 40% savings in logic resources compared with its HOG-linear SVM competitor. Hence, the proposed feature and classification setup is shown to be a better candidate as the single most discriminative pedestrian detector than the currently accepted HOG-linear SVM. Auteurs: Muhammad Bilal;Asim Khan;Muhammad Umar Karim Khan;Chong-Min Kyung; Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology Date publication: 10.-2017, volume: 27, issue:10, pages: 2260 - 2273 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Cost Time-Correlated Single Photon Counting System for Multiview Time-Domain Diffuse Optical Tomography
 Résumé:Diffuse optical tomography resorting to time-domain measurements (TD-DOT) provides information-rich data that have not yet been fully exploited for image reconstruction, notably to increase imaging spatial resolution. Current TD-DOT scanners suffer from a very low sensitivity owing to their small number of detection channels. This leads to excessively long acquisition times for in vivo imaging. To obtain a higher number of detection channels, thus increasing detection density, a low-cost time-correlated single photon counting (TCSPC) system dedicated to TD-DOT was designed, resorting solely to off-the-shelf electronic components to reduce costs, in distinction to custom application-specific integrated circuit solutions. The system features four input channels, each of them including a leading-edge discriminator for direct interfacing with off-the-shelf photodetector modules and a programmable delay line to compensate for undesired propagation delays, thus also avoiding manual adjustment of cable lengths. The system supports a large number of TCSPC channels using a daisy-chain configuration through an onboard Ethernet switch. It also features a 13.02 ps bin width with a 12.5 ns dynamic range. Results show excellent linearity, with a $\sigma _{\mathrm{ DNL}}$ of 1.7% least significant bit (LSB), peak differential nonlinearity of 5% LSB, and peak integral nonlinearity of 10% LSB and an average accuracy of 19 ps full-width at half-maximum (FWHM) throughout two separate four-channel systems. The system was tested in a TD-DOT acquisition setup, and 37 ps FWHM instrument response functions were obtained using a single-photon avalanche diode (SPAD) detector. Diffuse intrinsic measurements were also acquired and compared with a reference TCSPC system showing similar results. Auteurs: Jonathan Bouchard;Arnaud Samson;William Lemaire;Caroline Paulin;Jean-François Pratte;Yves Bérubé-Lauzière;Réjean Fontaine; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2505 - 2515 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Noise Area-Efficient Chopped VCO-Based CTDSM for Sensor Applications in 40-nm CMOS
 Résumé:An area-efficient voltage-sensing readout circuit employing chopped voltage-controlled oscillator (VCO)-based continuous-time delta-sigma modulator (CTDSM) is presented in this paper. This VCO-based CTDSM features direct connection to sensors to eliminate pre-amplifier for achieving better hardware efficiency. The VCO is designed as a trans-conductor current-controlled oscillator, which is a fully differential $G_{m}$ stage cascaded with two CCOs, to provide a high-input impedance to sense the voltage signals from sensors. Analysis shows that the main noise and offset contributor is the $G_{m}$ stage. This problem is mitigated by employing choppers at critical location within the circuit. The VCO-based CTDSM is implemented in a 40-nm CMOS process. The power consumption is $17~\mu \text{W}$ under 1.2-V supply. With a 4-mVp (8-mV $_{\textrm {pp}})$ input, it achieves 61.85-dB signal-to-noise-and-distortion ratio over a 5-kHz bandwidth and the total harmonic distortion is −70.8 dB. The input-referred noise is 32 nV/ $\surd$ Hz. The chip area is only 0.0145 mm $^{\textrm {2}}$ . Auteurs: Chih-Chan Tu;Yu-Kai Wang;Tsung-Hsien Lin; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2523 - 2532 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Power 28-nm CMOS FD-SOI Reflection Amplifier for an Active F-Band Reflectarray
 Résumé:A new topology of a low-power F-band reflection amplifier for active reflectarrays is proposed and demonstrated using a CMOS fully depleted silicon-on-insulator 28-nm process. The design enables frequency response and center frequency tuning, as well as phase control of the reflected signal. The chip consumes a core area of only $90\times 80~\mu\text{m}^{2}$ and is incorporated into a $2\times 2$ printed reflectarray antenna, implementing the first co-polarized active reflectarray. Such implementation enables, for the first time, active reflectarrays with dual polarization ability, which can be used for full-duplex links, as well as polarization diversity applications. Design considerations for a stable reflection amplifier, as well as measurement results of the reflection amplifier and reflectarray, are presented in this paper. Variable stable gain of 5–25 dB at the frequency range of 106–127 GHz was achieved, with noise figure of 10.5–11.7 dB. The total power consumption was 6–20 mW, depending on the chosen frequency response. An active antenna gain of 28 dBi was measured for the $2\times 2$ reflectarray. Auteurs: Naftali Landsberg;Eran Socher; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3910 - 3921 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Power High-Dynamic-Range Receiver System for In-Probe 3-D Ultrasonic Imaging
 Résumé:In this paper, a dual-mode low-power, high dynamic-range receiver circuit is designed for the interface with a capacitive micromachined ultrasonic transducer. The proposed ultrasound receiver chip enables the development of an in-probe digital beamforming imaging system. The flexibility of having two operation modes offers a high dynamic range with minimum power sacrifice. A prototype of the chip containing one receive channel, with one variable transimpedance amplifier (TIA) and one analog to digital converter (ADC) circuit is implemented. Combining variable gain TIA functionality with ADC gain settings achieves an enhanced overall high dynamic range, while low power dissipation is maintained. The chip is designed and fabricated in a 65 nm standard CMOS process technology. The test chip occupies an area of 76$\mu \text{m}\; \times$ 170 $\mu \text{m}$. A total average power range of 60–240 $\mu \text{W}$ for a sampling frequency of 30 MHz, and a center frequency of 5 MHz is measured. An instantaneous dynamic range of 50.5 dB with an overall dynamic range of 72 dB is obtained from the receiver circuit. Auteurs: Hourieh Attarzadeh;Ye Xu;Trond Ytterdal; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 10.-2017, volume: 11, issue:5, pages: 1053 - 1064 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Power SiGe BiCMOS 190-GHz Receiver With 47-dB Conversion Gain and 11-dB Noise Figure for Ultralarge-Bandwidth Applications
 Résumé:This paper presents a 190-GHz direct-conversion receiver capable of supporting higher order modulation schemes and implemented in a 130-nm SiGe BiCMOS technology. The circuit consists of a low-noise amplifier, an active fundamental mixer, a local-oscillator driver, a variable-gain baseband (BB) amplifier, and a totem-pole output stage. To exploit the advantages of sub-THz frequencies in terms of available bandwidth (BW) at a low dc power consumption, all circuit blocks are concurrently optimized for large BW and high power efficiency. A high and tunable conversion gain as well as a large maximum BB voltage swing is targeted to allow direct operation with state-of-the-art analog-to-digital converters. While consuming only 122 mW of dc power, the fabricated circuit exhibits a record 3-dB RF BW of 35 GHz, a maximum conversion gain of 47 dB with a tuning range of 20 dB, a maximum BB voltage swing of more than 800 $\text {mV}_{\mathrm{ pp}}$ , and a minimum double-sideband noise figure of 10.7 dB. Auteurs: David Fritsche;Gregor Tretter;Paul Stärke;Corrado Carta;Frank Ellinger; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 4002 - 4013 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Profile Dual-Polarized Patch Antenna With Stable Radiation Pattern Using Ground-Slot Groups and Metallic Ground Wall
 Résumé:A low-profile dual-polarized patch antenna with stable radiation pattern for use in base stations operating from 1.7 to 2.7 GHz is presented. The antenna consists of a square patch radiator placed at 20 mm ( $0.14\lambda _{0}$ at the center frequency of 2.2 GHz) above a square ground plane. For bandwidth enhancement, the square patch radiator is dual fed using four probes, each having a U-shape. Two wideband 180° baluns are designed using composite right/left handed transmission lines to generate two signals with same amplitude, but phase shift of 180° for the probes. The radiation pattern is stabilized using four slot groups on the ground plane and a metallic ground wall around the radiating patch. The antenna is studied and designed using computer simulation. Results show that the simulated half-power beamwidths have variations of only 4° and 5° in the elevation (EL) and azimuth (AZ) planes, respectively, across the operating band. Measured results show that the antenna has the impedance bandwidths of 1.68–2.83 GHz and 1.7–2.85 GHz for the two input ports, isolation of more than 38 dB, and cross-polarization of less than −20 dB at the boresight in both the EL and AZ planes. The measured boresight gains are 7.8 ± 0.6 dBi for both two ports, and the radiation efficiencies are 74%–84% and 73%–82% for ports 1 and 2, respectively. Auteurs: Qinlong Li;S. W. Cheung;Changfei Zhou; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5061 - 5068 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Profile Wide-Bandwidth Planar Inverted-F Antenna Under Dual Resonances: Principle and Design Approach
 Résumé:A low-profile planar inverted-F antenna (PIFA) under the operation of TM0,1/2 and TM2,1/2 modes in a single patch resonator for bandwidth enhancement is proposed. Initially, our study demonstrates that all of the even-order modes can effectively be suppressed by employing a rectangular PIFA instead of the conventional microstrip patch antenna. Then, a pair of shorting pins is appropriately loaded underneath the side-shorted radiating patch to investigate the variation of their odd-mode resonant frequencies. The results indicate that the resonant frequency of TM0,1/2 mode ( $f_{0,1/2}$ ) is dramatically increased up while almost maintaining that of TM2,1/2 mode ( $f_{2,1/2}$ ). After that, the width of the radiating patch is progressively enlarged in order to move the $f_{2,1/2}$ more closely to the $f_{0,1/2}$ . By using this approach, the dual radiative resonant modes can be reallocated in proximity to each other. Additionally, a narrow slot is etched out on the radiating patch so as to counteract the equivalent inductance caused by the shorting pins and probe. As such, a wide-bandwidth with stable radiation pattern is achieved for the PIFA under the operation of these dual-resonant modes. After the extensive analysis is executed, the proposed antenna is fabricated and tested. Simulated and measured results are found in good agreement with each other, demonstrating that its impedance bandwidth is tremendously widened to about 15.3% with appearance of two in-band attenuation poles. In particular, a low-profile property with the height of 0.036 free-space wavelength is achieved. Auteurs: Neng-Wu Liu;Lei Zhu;Wai-Wa Choi; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 10.-2017, volume: 65, issue:10, pages: 5019 - 5025 Editeur: IEEE Document complet vers site de l'éditeur
» A Lyapunov Function for Switching Command of a DC–DC Power Converter With an LC Input Filter
 Résumé:This paper describes a method to control a dc–dc switching power converter with an LC input filter working under continuous conduction mode. It is known that the interaction between the low-pass filter and the tightly controlled switching converter occurs, and it might lead to an instability operation. The idea of this method relies on the Lyapunov stability criterion. The switching command of this control is defined by the manner of pre-evaluating the stability of the controlled system. All state variables are controlled in the same time. Therefore, the responses of this controlled system are fast while guaranteeing a stable operation. The proposed control is applied to a boost converter to demonstrate the implementation and its performance. The simulation and experimental results validate the proposed control approach. Auteurs: Roghayeh Gavagsaz-Ghoachani;Matheepot Phattanasak;Jean-Philippe Martin;Serge Pierfederici;Babak Nahid-Mobarakeh;Pierre Riedinger; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 5041 - 5050 Editeur: IEEE Document complet vers site de l'éditeur
» A Magnetic Plethysmograph Probe for Local Pulse Wave Velocity Measurement
 Résumé:Objective: We present the design and experimental validation of an arterial compliance probe with dual magnetic plethysmograph (MPG) transducers for local pulse wave velocity (PWV) measurement. The MPG transducers (positioned at 23 mm distance apart) utilizes Hall-effect sensors and permanent magnets for arterial blood pulse detection. Methods: The MPG probe was initially validated on an arterial flow phantom using a reference method. Further, 20 normotensive subjects (14 males, age = 24 ± 3.5 years) were studied under two different physical conditions: 1) Physically relaxed condition, 2) Postexercise condition. Local PWV was measured from the left carotid artery using the MPG probe. Brachial blood pressure (BP) was measured to investigate the correlation of BP with local PWV. Results: The proposed MPG arterial compliance probe was capable of detecting high-fidelity blood pulse waveforms. Reliable local pulse transit time estimates were assessed by the developed measurement system. Beat-by-beat local PWV was measured from multiple subjects under different physical conditions. A profound increment was observed in the carotid local PWV for all subjects after exercise (average increment = 0.42 ± 0.22 m/s). Local PWV values and brachial BP parameters were significantly correlated (r ≥ 0.72), except for pulse pressure (r = 0.42). Conclusion: MPG arterial compliance probe for local PWV measurement was validated. Carotid local PWV measurement, its variations due to physical exercise and correlation with BP levels were examined during the in vivo study. Significance: A novel dual MPG probe for local PWV measurement and potential use in cuffless BP measurement. Auteurs: Nabeel P M;Jayaraj Joseph;Mohanasankar Sivaprakasam; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 10.-2017, volume: 11, issue:5, pages: 1065 - 1076 Editeur: IEEE Document complet vers site de l'éditeur
» A Magnetically Coupled Communication and Charging Platform for Microsensors
 Résumé:A double layer spiral antenna with side length of $740~\mu \text{m}$ was fabricated by a multilayer electroplating process and bonded with an radio frequency identification chip by silver epoxy to form a microsensor chip. A theoretical power transfer model was built to optimize the power transfer efficiency. The resonant frequency of the microsensor was characterized inside a small coupling loop, exhibiting a high degree of agreement with theoretical results. A magnetically coupled communication and charging platform was developed to work with the microsensors. The reader antenna was composed of a coupling loop and a secondary coil with 40-mm diameter wrapped around a polycarbonate tube. To maximize the magnetic field generated inside the secondary coil, a lump circuit model was built and its resonant modes were analyzed. The maximum current inside the secondary coil was achieved at the serial resonant frequency, at which the current followed a sinusoidal distribution along the coil. The magnetic field distribution inside the coil was calculated to analyze the read-out of the reader antenna. The communication and power transfer was demonstrated with the microsensors flowing through the reader antenna by successfully retrieving the sensor ID. [2016-0318] Auteurs: Guangwu Duan;Xiaoguang Zhao;Xin Zhang; Apparue dans: Journal of Microelectromechanical Systems Date publication: 10.-2017, volume: 26, issue:5, pages: 1099 - 1109 Editeur: IEEE Document complet vers site de l'éditeur
» A Mean-Field Game of Evacuation in Multilevel Building
 Résumé:This paper puts forward a simple mean-field game that captures some of the key dynamic features of crowd and pedestrian flows in multilevel building evacuations. It considers both microscopic and macroscopic route choice by strategic agents. To achieve this, we use mean-field differential game with local congestion measure based on the location of the agent in the building. Including the local mean-field term and its evolution along the path causes a sort of dispersion of the flow: the agents will try to avoid high density areas in order to reduce their overall walking costs and queuing costs at the stairs and exits. Each agent state is represented by a center of a box that follows a simple first-order dynamical system in an Euclidean space. Each agent will move to one of the closest exits that is safer and with less congested path. First, we formulate the problem and derive optimality equations using maximum principle and dynamic programming with boundary conditions. Second, well posedness and existence results are provided. Numerics and simulations are carried out to illustrate mean-field equilibria of a safer evacuation process. Finally, the methodology is shown to be flexible enough to include movement noises and stochastic structural component of the building. Auteurs: Boualem Djehiche;Alain Tcheukam;Hamidou Tembine; Apparue dans: IEEE Transactions on Automatic Control Date publication: 10.-2017, volume: 62, issue:10, pages: 5154 - 5169 Editeur: IEEE Document complet vers site de l'éditeur
» A MEMS Condenser Microphone-Based Intracochlear Acoustic Receiver
 Résumé:Goal: Intracochlear sound pressure (ICSP) measurements are limited by the small dimensions of the human inner ear and the requirements imposed by the liquid medium. A robust intracochlear acoustic receiver (ICAR) for repeated use with a simple data acquisition system that provides the required high sensitivity and small dimensions does not yet exist. The work described in this report aims to fill this gap and presents a new microelectromechanical systems (MEMS) condenser microphone (CMIC)-based ICAR concept suitable for ICSP measurements in human temporal bones. Methods: The ICAR head consisted of a passive protective diaphragm (PD) sealing the MEMS CMIC against the liquid medium, enabling insertion into the inner ear. The components of the MEMS CMIC-based ICAR were expressed by a lumped element model (LEM) and compared to the performance of successfully fabricated ICARs. Results: Good agreement was achieved between the LEM and the measurements with different sizes of the PD. The ICSP measurements in a human cadaver temporal bone yielded data in agreement with the literature. Conclusion: Our results confirm that the presented MEMS CMIC-based ICAR is a promising technology for measuring ICSP in human temporal bones in the audible frequency range. Significance: A sensor for evaluation of the biomechanical hearing process by quantification of ICSP is presented. The concept has potential as an acoustic receiver in totally implantable cochlear implants. Auteurs: Flurin Pfiffner;Lukas Prochazka;Dominik Péus;Ivo Dobrev;Adrian Dalbert;Jae Hoon Sim;Rahel Kesterke;Joris Walraevens;Francesca Harris;Christof Röösli;Dominik Obrist;Alexander Huber; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 10.-2017, volume: 64, issue:10, pages: 2431 - 2438 Editeur: IEEE Document complet vers site de l'éditeur
» A MEMS Tensile Testing Technique for Measuring True Activation Volume and Effective Stress in Nanocrystalline Ultrathin Microbeams
 Résumé:Signature parameters, such as true activation volume and effective stress, are often characterized to identify the governing plastic deformation mechanisms, including that of nanocrystalline metals. The accurate measurement of these parameters using transient tests was recently questioned for nanocrystalline metals, in which grain-boundary-based mechanisms can concurrently occur with dislocation glide. Here, we demonstrate the use of a microelectromechanical systems (MEMS) device to measure true activation volume and effective stress based on repeated stress relaxation and stress dip experiments, respectively. The technique was demonstrated on 100-nm-thick nanocrystalline Au microbeams. These miniaturized tests open up the possibility of observing the mechanisms directly under a transmission electron microscope, and providing a direct link between these measured parameters and the governing mechanisms. [2016-0306] Auteurs: Saurabh Gupta;Olivier N. Pierron; Apparue dans: Journal of Microelectromechanical Systems Date publication: 10.-2017, volume: 26, issue:5, pages: 1082 - 1092 Editeur: IEEE Document complet vers site de l'éditeur
» A Metacoupler for Converting Propagating Waves to Guided Waves in Wire Waveguides
 Résumé:Propagating electromagnetic waves in free space cannot directly couple to guided waves in waveguides due to momentum mismatch. Here, we propose a method to design a metacoupler that can convert propagating waves into guided waves along wire waveguides in a noninvasive way. The metacoupler is attached to the wire waveguide and imposes an additional wave vector to the scattered waves, thus, filling the momentum gap between the propagating waves and guided waves. Numerical simulations have confirmed the conversion effect in corrugated metal wire and silicon wire waveguides. Auteurs: Hongchen Chu;Jie Luo;Yun Lai; Apparue dans: IEEE Photonics Journal Date publication: 10.-2017, volume: 9, issue:5, pages: 1 - 7 Editeur: IEEE Document complet vers site de l'éditeur
» A Methodology for Designing and Evaluating Cloud Scheduling Strategies in Distributed Videoconferencing Systems
 Résumé:Over the last few years, videoconferencing systems have experienced several changes that enable videoconferencing applications in personal devices to a high number of users. To efficiently attend this high and variable demand, deploying distributed videoconferencing servers in cloud-based infrastructures is highly recommended. However, videoconferencing systems have particular characteristics that impede the application of regular resource scheduling solutions used in other kinds of distributed environments. In this paper, we propose a methodology to design and evaluate scheduling strategies adapted to the necessities of each specific scenario. It involves using a new metric to estimate the resource consumption of each connection and provides a set of coefficients to evaluate the efficiency of the strategy. We test the methodology in a real setup and compare the behavior and performance of three scheduling algorithms. The conclusion is that the proposed methodology allows us to configure decision policies adapted to the requirements and necessities of a range of use cases. Thereby, we achieve a more efficient way of using cloud resources, improving the service performance and saving costs. Auteurs: Álvaro Alonso;Ignacio Aguado;Joaquín Salvachúa;Pedro Rodríguez; Apparue dans: IEEE Transactions on Multimedia Date publication: 10.-2017, volume: 19, issue:10, pages: 2282 - 2292 Editeur: IEEE Document complet vers site de l'éditeur
» A Microwave Photonics Fiber Loop Ring-Down System
 Résumé:A microwave photonics fiber loop ring-down system is demonstrated in this paper. In comparison with the traditional time domain fiber loop ring-down setup, the demonstrated system is based on pure frequency domain measurement from a microwave-photonic configuration. The system consists of a direct-modulation laser with its modulation frequency scanned by a vector network analyzer. The amplitude and phase spectra of the demonstrated fiber loop ring-down system are then recorded, followed by a complex Fourier transform to acquire the ring-down curve in the time domain. The loss of the fiber loop can then be evaluated based on the calculated ring-down curve. The system delivers high signal-to-noise ratio, and averaging is not required compared with the traditional time domain measurement. The system is also insensitive to the sources of environmental noise. The measurement principle, experimental setup, and the mathematical model of the system are discussed in this paper. A proof-of-concept macrobending loss test is demonstrated. Auteurs: Yiyang Zhuang;Yang Du;Chen Zhu;Mohammed Farhan Ahmed;Yizheng Chen;Rex E. Gerald;Jie Huang; Apparue dans: IEEE Sensors Journal Date publication: 10.-2017, volume: 17, issue:20, pages: 6565 - 6570 Editeur: IEEE Document complet vers site de l'éditeur
» A Miniature Ultrawideband Electric Field Probe Based on Coax-Thru-Hole via Array for Near-Field Measurement
 Résumé:In this paper, a miniature electric field probe with an ultrawideband of 9 kHz–20 GHz is proposed, fabricated, and tested. The electric field probe is fabricated on a four-layer printed circuit board using high-performance and low-loss Rogers material ( $\varepsilon _{\mathrm{r}}= 3.48$ and tan $\delta = 0.0037$ ). Coax-thru-hole via array is used to control the signal via impedance to achieve impedance $50~\Omega$ match over the whole working band, reducing the harmful influence on the probe’s characteristic. The ground vias, called via fence, are utilized to suppress the resonance caused by the parallel-plate mode of conductor-backed coplanar waveguide (CB-CPW), expanding the working frequency band. Experimental result shows $\vert S_{21}\vert$ rather smooth in operation band, demonstrating the working frequency band is up to 9 kHz–20 GHz. The electric field probe has a 2–3 mm spatial resolution, which has a good ability to locate the interference source. Auteurs: Zhaowen Yan;Jianwei Wang;Wei Zhang;Yansheng Wang;Jun Fan; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 10.-2017, volume: 66, issue:10, pages: 2762 - 2770 Editeur: IEEE Document complet vers site de l'éditeur
» A Miniaturized Dual-Band FSS With Controllable Frequency Resonances
 Résumé:A novel dual-band miniaturized frequency-selective surface (FSS) is proposed in this letter. The proposed FSS is composed of cross dipole aperture element combined with meandered monopole aperture element. The single layer FSS provides two pass-bands centered at 5.13 and 8.85 GHz with bandwidth of 1.27 and 1.33 GHz, respectively. The two pass-band frequencies of the designed FSS can be controlled independently by simply changing structure parameters of the unit cell. In addition, the dual-band FSS designed using the miniaturized element exhibits excellent resonance stability for different polarizations and incident angles. A prototype of the proposed FSS is fabricated and measured. A good agreement between the simulation and the measured results is obtained, which demonstrates the stable performance of the FSS. Auteurs: Xian-Jun Sheng;Jing-Jing Fan;Ning Liu;Chun-Bo Zhang; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 915 - 917 Editeur: IEEE Document complet vers site de l'éditeur
» A Minimized 2-D Left-Handed Material Spiral Unit Cell With Rotation Symmetry for Midrange Wireless Power Transfer
 Résumé:This letter presents a technique for designing left-handed material (LHM) unit cell, and a minimized 2-D low-loss LHM square spiral unit cell ( $38~ \text {mm} \times 38 ~\text {mm} \times 1.6 ~\text {mm}$ ) with rotation symmetry is developed in the frequency band 13.56–14 MHz. Two LHM slabs with $5 \times 5$ unit cell array are added to the transmission and receiving antennas, respectively, and the power transfer efficiency has increased greatly. Auteurs: Hui-Fen Huang;Ting Li; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 10.-2017, volume: 27, issue:10, pages: 882 - 884 Editeur: IEEE Document complet vers site de l'éditeur
» A Mobility Model for Random Discrete Dopants and Application to the Current Drivability of DRAM Cell
 Résumé:A new impurity mobility model suitable for the TCAD simulation of the random discrete dopant (RDD) has been proposed. The proposed model has been applied to the DRAM cell transistor of the 20-nm technology generation. The RDD effect in the drain region of the cell transistor alone gives relative standard variation in the driving current of ~3%. Auteurs: Hoin Yu;Daewon Kim;Sungman Rhee;Seongwook Choi;Young June Park; Apparue dans: IEEE Transactions on Electron Devices Date publication: 10.-2017, volume: 64, issue:10, pages: 4246 - 4251 Editeur: IEEE Document complet vers site de l'éditeur
» A Model for Designing Ultralow Noise Single- and Dual-Loop 10-GHz Optoelectronic Oscillators
 Résumé:A complete model describing both single- and dual-loop optoelectronic oscillators (OEO) is introduced. It is compared to several experimental configurations, with excellent agreement in all cases. The physical insight into noise coupling mechanisms brought by the model further allows us for the design of ultralow noise OEO. Phase noise performances at 10 GHz with a single 1 km delay line and with a dual 1 km/100 m delay lines are reported. An optimized dual loop configuration exhibits low phase noise floor at high offset frequency (–160 dBc/Hz at 100 kHz) and low spur levels (–145 dBc/Hz), here again in close agreement with our model. Auteurs: Oriane Lelièvre;Vincent Crozatier;Perrine Berger;Ghaya Baili;Olivier Llopis;Daniel Dolfi;Pascale Nouchi;Fabienne Goldfarb;Fabien Bretenaker;Loïc Morvan;Grégoire Pillet; Apparue dans: Journal of Lightwave Technology Date publication: 10.-2017, volume: 35, issue:20, pages: 4366 - 4374 Editeur: IEEE Document complet vers site de l'éditeur
» A Model-Based Predictive Direct Power Control for Traction Line-Side Converter in High-Speed Railway
 Résumé:With the rapid development of China high-speed railway, the low frequency oscillation (LFO) of electrical quantities appears more often recently and leads to some severe problems of train operation. To improve the traction line-side converter control and suppress the phenomenon economically and effectively, a model-based predictive direct power control (MPDPC) approach is proposed in this paper. The approach adopts a discrete-time model of traction line-side converter in d–q reference frame to predict the future values of the input active and reactive power. The optimal switching state is selected by minimizing a cost function of power to evaluate the power errors at the next sampling time. Through the theoretical analysis and simulations, the performance of MPDPC is compared with traditional transient direct current control (TDCC) that is widely adopted in China Railway High-Speed 3 electric-multiple-unit. The real-time online simulations based on Real-Time Laboratory (RT-LAB) are also realized to further validate the results. Moreover, two vehicle-grid cascade simulation systems are constructed, and the LFO suppressing capability of MPDPC and TDCC is compared. Finally, the steady-state characteristic, dynamic characteristic, and LFO suppressing capability of MPDPC are demonstrated through the analysis of key performance indexes. Auteurs: Zhigang Liu;Chuan Xiang;Yaqi Wang;Yicheng Liao;Guinan Zhang; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4934 - 4943 Editeur: IEEE Document complet vers site de l'éditeur
» A Modified T-Structured Three-Level Inverter Configuration Optimized With Respect to PWM Strategy Used for Common-Mode Voltage Elimination
 Résumé:This paper presents an optimized topology for a ${\text{3}}-\phi$ three-level inverter with complete elimination of common-mode voltage (CMV). The proposed multilevel inverter (MLI) configuration is realized by modifying a T-structure ${\text{3}}-\phi$ inverter. The proposed configuration is an optimized solution with respect to the pulse-width modulation strategy used for CMV elimination. The given three-level inverter structure uses only 16 power semiconductor switches, which is much lower than the existing configurations. A reduced number of power semiconductor devices results in a diminished number of driver circuits, less installation space, and low cost. Further, due to the complete elimination of CMV, the proposed MLI is free from issues such as electromagnetic interference and leakage current with a reduction in filter requirement. The presented topology is also compared with other existing topologies to prove its advantage. It is an optimized solution with respect to the dc bus voltage requirement and the total voltage rating of the devices or the components used in the system. Simulation and experimental results are presented to confirm the capability of the proposed MLI. Auteurs: Arpan Hota;Sachin Jain;Vivek Agarwal; Apparue dans: IEEE Transactions on Industry Applications Date publication: 10.-2017, volume: 53, issue:5, pages: 4779 - 4787 Editeur: IEEE Document complet vers site de l'éditeur
» A Multigigabit per Second Integrated Multiple-Input Multiple-Output VLC Demonstrator
 Résumé:In this paper, we report the performance of an imaging multiple-input multiple-output (MIMO) visible light communication (VLC) system. The VLC transmitter consists of a two-dimensional (2-D), individually addressable Gallium Nitride micro light-emitting diode (μLED) array. The receiver uses a 2-D avalanche photodiode array fabricated using complementary metal oxide semiconductor (CMOS). Using integrated CMOS-based LED drivers, a data rate greater than 1 Gb/s was obtained at a link distance of 1 m with the system field of view of 3.45° using four channels. At a reduced link distance of 0.5 m, a data rate of 7.48 Gb/s was obtained using a nine channel MIMO system. This demonstrates the feasibility of compact MIMO systems that offer substantial data rates. Auteurs: Sujan Rajbhandari;Aravind V. N. Jalajakumari;Hyunchae Chun;Grahame Faulkner;Katherine Cameron;Robert Henderson;Dobroslav Tsonev;Harald Haas;Enyuan Xie;Jonathan J. D. McKendry;Johannes Herrnsdorf;Ricardo Ferreira;Erdan Gu;Martin D. Dawson;Dominic O&#x Apparue dans: Journal of Lightwave Technology Date publication: 10.-2017, volume: 35, issue:20, pages: 4358 - 4365 Editeur: IEEE Document complet vers site de l'éditeur
» A Multilevel Artificial Neural Network Nonlinear Equalizer for Millimeter-Wave Mobile Fronthaul Systems
 Résumé:We propose and validate a complex-valued multilevel artificial neural network nonlinear equalizer (ANN-NLE) for single-carrier 16QAM and 64QAM signals transmissions in the 60-GHz radio-over-fiber (RoF) transmission system. First, we analyze the nonlinearities in the fiber-wireless channels. Then, we introduce the principles of the multilevel ANN-NLE proposed for the millimeter-wave RoF systems. From the analysis of nonlinearities in a single-carrier optical transmission channel, it is essential to design a complex-valued ANN-NLE to mitigate the cross-modulation (XM) effects between the in-phase (I) and quadrature-phase (Q) components. Finally, we report on single-carrier signaling at 16QAM and 64QAM on 60 GHz, demonstrating the ability of the proposed ANN-NLE approach to minimize the nonlinear compression in an RoF system. As an added benefit, the complex-valued ANN-NLE has a great tolerance to phase rotations. The convergence time, activation function, step size, and number of taps are discussed in Section IV. Auteurs: Siming Liu;Mu Xu;Jing Wang;Feng Lu;Weiheng Zhang;Huiping Tian;Gee-Kung Chang; Apparue dans: Journal of Lightwave Technology Date publication: 10.-2017, volume: 35, issue:20, pages: 4406 - 4417 Editeur: IEEE Document complet vers site de l'éditeur
» A Multilevel Inverter Structure Based on a Combination of Switched-Capacitors and DC Sources
 Résumé:This paper presents a switched-capacitor multilevel inverter (SCMLI) combined with multiple asymmetric dc sources. The main advantage of proposed inverter with similar cascaded MLIs is reducing the number of isolated dc sources and replacing them with capacitors. A self-balanced asymmetrical charging pattern is introduced in order to boost the voltage and create more voltage levels. Number of circuit components such as active switches, diodes, capacitors, drivers, and dc sources reduces in proposed structure. This multistage hybrid MLI increases the total voltage of used dc sources by multiple charging of the capacitors stage by stage. A bipolar output voltage can be inherently achieved in this structure without using single phase H-bridge inverter that was used in traditional SCMLIs to generate negative voltage levels. This eliminates requirements of high-voltage rating elements to achieve negative voltage levels. A 55-level step-up output voltage (27 positive levels, a zero level, and 27 negative levels) are achieved by a three-stage system that uses only three asymmetrical dc sources (with amplitude of 1 Vin, 2 V in, and 3 Vin) and seven capacitors (self-balanced as multiples of 1 Vin). MATLAB/SIMULINK simulation results and experimental tests are given to validate the performance of proposed circuit. Auteurs: Amir Taghvaie;Jafar Adabi;Mohammad Rezanejad; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 10.-2017, volume: 13, issue:5, pages: 2162 - 2171 Editeur: IEEE Document complet vers site de l'éditeur
» A Necessary and Sufficient Condition for Having Independent TE and TM Modes in an Anisotropic Waveguide
 Résumé:In a metallic waveguide filled with a lossless anisotropic medium, do independent transverse electric (TE) and transverse magnetic (TM) modes exist? If so, under what conditions? This is a fundamental problem in the electromagnetic waveguide theory, but so far no definitive answers have been published in existing references. This paper proposes a sufficient and necessary condition for this theoretic electromagnetic waveguide problem based on both classic waveguide theory in electromagnetics and basic knowledge in mathematics. Moreover, we prove that for the independent TE modes, the propagation constants obtained from both the longitudinal scalar magnetic field simulation and the transverse vector electric field simulation are the same, and for the independent TM modes, the propagation constants obtained from both the longitudinal scalar electric field simulation and the transverse vector magnetic field simulation are the same. Finally, we validate the correctness of this sufficient and necessary condition by several numerical experiments based on the finite-element method. Therefore, this is a new theoretical result in the electromagnetic waveguide theory, and is expected to be valuable for the design of waveguides filled with anisotropic media. Auteurs: Wei Jiang;Jie Liu;Tian Xia;Na Liu;Qing Huo Liu; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 10.-2017, volume: 65, issue:10, pages: 3660 - 3670 Editeur: IEEE Document complet vers site de l'éditeur
» A Neuromorphic Chip Optimized for Deep Learning and CMOS Technology With Time-Domain Analog and Digital Mixed-Signal Processing
 Résumé:Demand for highly energy-efficient coprocessor for the inference computation of deep neural networks is increasing. We propose the time-domain neural network (TDNN), which employs time-domain analog and digital mixed-signal processing (TDAMS) that uses delay time as the analog signal. TDNN not only exploits energy-efficient analog computing, but also enables fully spatially unrolled architecture by the hardware-efficient feature of TDAMS. The proposed fully spatially unrolled architecture reduces energy-hungry data moving for weight and activations, thus contributing to significant improvement of energy efficiency. We also propose useful training techniques that mitigate the non-ideal effect of analog circuits, which enables to simplify the circuits and leads to maximizing the energy efficiency. The proof-of-concept chip shows unprecedentedly high energy efficiency of 48.2 TSop/s/W. Auteurs: Daisuke Miyashita;Shouhei Kousai;Tomoya Suzuki;Jun Deguchi; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 10.-2017, volume: 52, issue:10, pages: 2679 - 2689 Editeur: IEEE Document complet vers site de l'éditeur
» A New Approach to Solve the Constrained OWA Aggregation Problem
 Résumé:Constrained ordered weighted averaging (OWA) aggregation attempts to optimize the OWA aggregation problem with multiple constraints. It is inherently nonlinear, and Yager presented a novel method to transform the nonlinear problem to a mixed integer linear problem. Later, a simple algorithm for exact computation of optimal solutions to a single constrained OWA aggregation problem was presented. In this paper, we deal with the same problem, but in completely different ways in a sense that it is linearized by utilizing the reordering property of the OWA operators. We attempt to solve the linear programming problem via the extreme points in lieu of using a linear programming package for the purpose of deriving an explicit formula for the optimal solution. Furthermore, we consider its dual problem that leads to an equivalent optimal solution. Finally, the proposed method is extended to the OWA optimization problem with multiple constraints including the attitudinal character as well as a range of incomplete arguments. Auteurs: Byeong Seok Ahn; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 10.-2017, volume: 25, issue:5, pages: 1231 - 1238 Editeur: IEEE Document complet vers site de l'éditeur

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