###### Accueil » Publications dans le domaines des technologies » 08-2017
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» $H_2$-Control of Continuous-Time Hidden Markov Jump Linear Systems
 Résumé:This technical note addresses the $H_2$ -control problem for a continuous-time Markov Jump Linear System (MJLS) with partial information on the mode of operation. The jumps of the system depend on a continuous-time hidden Markov model (CT-HMM) where the hidden process represents the dynamics of the real system, while the emitted signal represents the information available to the controller. We start by analyzing the stochastic stability control problem with the goal to design a state feedback linear controller that stochastically stabilizes the closed-loop system, relying on the information from the detector. Two dual formulations, based on LMI problems, are derived as a solution for this problem. These results are then extended to the $H_2$ guaranteed cost control problem. The technical note is concluded with a numerical example which illustrates the derived results. Auteurs: F. Stadtmann;O. L. V. Costa; Apparue dans: IEEE Transactions on Automatic Control Date publication: 08.-2017, volume: 62, issue:8, pages: 4031 - 4037 Editeur: IEEE Document complet vers site de l'éditeur
» $K$ -Band Substrate-Integrated Waveguide Filter Using TM21 Mode With Enhanced Stopband Attenuation
 Résumé:In this letter, we present a method for enhancing the stopband attenuation performance of a $K$ -band TM21 mode filter using substrate-integrated waveguide resonators. To improve the stopband response, we suppress and move spurious resonant peaks and produce transmission zeros. The step-by-step procedure of the proposed three-step method is shown in detail. The measurements show that when using the presented method, the filters exhibit better stopband performances than those in which the presented steps are not followed. Auteurs: Boyoung Lee;Seunggoo Nam;Beyoungyoun Koh;Juseop Lee; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 08.-2017, volume: 27, issue:8, pages: 700 - 702 Editeur: IEEE Document complet vers site de l'éditeur
» $\mathbb {Z}_{2}\mathbb {Z}_{2}[u]$ –Cyclic and Constacyclic Codes
 Résumé:Following the very recent studies on ℤ2ℤ4-additive codes, ℤ2ℤ2[u]-linear codes have been introduced by Aydogdu et al. In this paper, we introduce and study the algebraic structure of cyclic, constacyclic codes and their duals over the R-module Z2α Rβ where R = ℤ2+uℤ2 = {0, 1, u, u + 1} is the ring with four elements and u2 = 0. We determine the generating independent sets and the types and sizes of both such codes and their duals. Finally, we present a bound and an optimal family of codes attaining this bound and also give some illustrative examples of binary codes that have good parameters which are obtained from the cyclic codes in Z2α Rβ. Auteurs: Ismail Aydogdu;Taher Abualrub;Irfan Siap; Apparue dans: IEEE Transactions on Information Theory Date publication: 08.-2017, volume: 63, issue:8, pages: 4883 - 4893 Editeur: IEEE Document complet vers site de l'éditeur
» $\mathbb {Z}_{2}\mathbb {Z}_{2}[u]$ –Cyclic and Constacyclic Codes
 Résumé:Following the very recent studies on ℤ2ℤ4-additive codes, ℤ2ℤ2[u]-linear codes have been introduced by Aydogdu et al. In this paper, we introduce and study the algebraic structure of cyclic, constacyclic codes and their duals over the R-module Z2α Rβ where R = ℤ2+uℤ2 = {0, 1, u, u + 1} is the ring with four elements and u2 = 0. We determine the generating independent sets and the types and sizes of both such codes and their duals. Finally, we present a bound and an optimal family of codes attaining this bound and also give some illustrative examples of binary codes that have good parameters which are obtained from the cyclic codes in Z2α Rβ. Auteurs: Ismail Aydogdu;Taher Abualrub;Irfan Siap; Apparue dans: IEEE Transactions on Information Theory Date publication: 08.-2017, volume: 63, issue:8, pages: 4883 - 4893 Editeur: IEEE Document complet vers site de l'éditeur
» $\mathbb {Z}_{2}\mathbb {Z}_{2}[u]$ –Cyclic and Constacyclic Codes
 Résumé:Following the very recent studies on ℤ2ℤ4-additive codes, ℤ2ℤ2[u]-linear codes have been introduced by Aydogdu et al. In this paper, we introduce and study the algebraic structure of cyclic, constacyclic codes and their duals over the R-module Z2α Rβ where R = ℤ2+uℤ2 = {0, 1, u, u + 1} is the ring with four elements and u2 = 0. We determine the generating independent sets and the types and sizes of both such codes and their duals. Finally, we present a bound and an optimal family of codes attaining this bound and also give some illustrative examples of binary codes that have good parameters which are obtained from the cyclic codes in Z2α Rβ. Auteurs: Ismail Aydogdu;Taher Abualrub;Irfan Siap; Apparue dans: IEEE Transactions on Information Theory Date publication: 08.-2017, volume: 63, issue:8, pages: 4883 - 4893 Editeur: IEEE Document complet vers site de l'éditeur
» $\mathbb {Z}_{2}\mathbb {Z}_{2}[u]$ –Cyclic and Constacyclic Codes
 Résumé:Following the very recent studies on ℤ2ℤ4-additive codes, ℤ2ℤ2[u]-linear codes have been introduced by Aydogdu et al. In this paper, we introduce and study the algebraic structure of cyclic, constacyclic codes and their duals over the R-module Z2α Rβ where R = ℤ2+uℤ2 = {0, 1, u, u + 1} is the ring with four elements and u2 = 0. We determine the generating independent sets and the types and sizes of both such codes and their duals. Finally, we present a bound and an optimal family of codes attaining this bound and also give some illustrative examples of binary codes that have good parameters which are obtained from the cyclic codes in Z2α Rβ. Auteurs: Ismail Aydogdu;Taher Abualrub;Irfan Siap; Apparue dans: IEEE Transactions on Information Theory Date publication: 08.-2017, volume: 63, issue:8, pages: 4883 - 4893 Editeur: IEEE Document complet vers site de l'éditeur
» 1.1-kV Vertical GaN p-n Diodes With p-GaN Regrown by Molecular Beam Epitaxy
 Résumé:High-voltage vertical regrown p-n junction diodes on bulk GaN substrates are reported in this letter with molecular-beam-epitaxy regrown p-GaN on metalorganic-chemical-vapor-deposition grown n-GaN drift region. The highest breakdown voltage is measured at 1135 V, and the differential on-resistance is 3.9 mOhm.cm2 at room temperature. The forward I–V show a turn-ON voltage near 3.9 V and an ideality factor of 2.5. Electroluminescence measurement of regrown p-n junctions shows ~30 times reduced emission intensity compared with as-grown p-n junctions, indicating presence of excessive non-radiative recombination centers introduced by the regrowth process. Temperature dependent reverse I–V measurements suggest that variable range hopping inside the depleted regrown p-GaN layer is likely the mechanism of the reverse leakage. This is the first high-voltage vertical regrown p-n junction ever reported in the GaN system. Auteurs: Zongyang Hu;Kazuki Nomoto;Meng Qi;Wenshen Li;Mingda Zhu;Xiang Gao;Debdeep Jena;Huili Grace Xing; Apparue dans: IEEE Electron Device Letters Date publication: 08.-2017, volume: 38, issue:8, pages: 1071 - 1074 Editeur: IEEE Document complet vers site de l'éditeur
» 2-D Wind Velocity Measurement Using a Vertically Suspended Optical Fiber Combined With a Photosensor Array
 Résumé:A novel low-cost 2-D wind velocity (speed and direction) sensor was designed based on the principles of statics and optics. A vertically suspended optical fiber was employed in the designed sensor as the sensitive element, which could be deflected by the applied force of airflow in 2-D horizontal planes. An optical signal emitted from the end of the fiber was projected onto a charge coupled device (CCD) array detector, which could recognize the offset magnitude and direction through image processing. The mathematic expression between the displacement of the light spot projected onto the CCD and the wind speed was derived. Preliminary wind tunnel experiments validated the correctness of the theoretical derivation, and the results also showed that the designed sensor had good precision (particularly in low wind speed). Auteurs: Qing-Hao Meng;Pei-Feng Qi;Kai Wu;Shao-Hui Zhu;Ming Zeng; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 08.-2017, volume: 66, issue:8, pages: 2074 - 2082 Editeur: IEEE Document complet vers site de l'éditeur
» 2017 Outstanding Chapter Awards, New Chapters, and Regional Chapter News [Chapter News]
 Résumé:Presents the recipients of the APS society 2017 Outstanding Chapter Awards as well as recent activiies of new chapters and regional chapter news. Auteurs: Ajay K. Poddar; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 08.-2017, volume: 59, issue:4, pages: 7 - 75 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D Frequency-Selective Rasorber With Wide Upper Absorption Band
 Résumé:This communication presents a 3-D frequency-selective rasorber (FSR) that has a passband with a low insertion loss and two absorption bands at both sides of the passband. A lossless and two lossy resonators are employed in the unit cell of the periodic structure to produce the passband and the absorption bands, respectively. Utilizing the techniques of stepped impedance resonator and capacitor loading, the thickness of the resonators is reduced. Moreover, the capacitor loading also frees the tuning of each resonant frequency of the lossy resonator, which facilitates the FSR design. The multiresonances of the lossy resonators are also employed to obtain a wide upper absorption band. An equivalent circuit model is established for understanding the operating principle. A prototype of the proposed FSR is fabricated and measured. Good agreement between measured and simulated results validates our FSR design. Auteurs: Yufeng Yu;Zhongxiang Shen;Tianwei Deng;Guoqing Luo; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 08.-2017, volume: 65, issue:8, pages: 4363 - 4367 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D MIMO: How Much Does It Meet Our Expectations Observed From Channel Measurements?
 Résumé:By taking advantage of the elevation domain, three-dimensional (3-D) multiple input and multiple output (MIMO) with massive antenna elements is considered as a promising and practical technique for the fifth Generation mobile communication system. So far, 3-D MIMO is mostly studied by simulation and a few field trials have been launched recently. It still remains unknown how much does the 3-D MIMO meet our expectations in versatile scenarios. In this paper, we answer this based on measurements with $56\times 32$ antenna elements at 3.5 GHz with 100-MHz bandwidth in three typical deployment scenarios, including outdoor to indoor (O2I), urban microcell (UMi), and urban macrocell (UMa). Each scenario contains two different site locations and 2–5 test routes under the same configuration. Based on the measured data, both elevation and azimuth angles are extracted and their stochastic behaviors are investigated. Then, we reconstruct two-dimensional and 3-D MIMO channels based on the measured data, and compare the capacity and eigenvalues distribution. It is observed that 3-D MIMO channel which fully utilizes the elevation domain does improve capacity and also enhance the contributing eigenvalue number. However, this gain varies from scenario to scenario in reality, O2I is the most beneficial scenario, then followed by UMi and UMa scenarios. More results of multiuser capacity varying with the scenario, antenna number and user number can provide the experimental insights for the efficient utilization of 3-D MIMO in future. Auteurs: Jianhua Zhang;Yuxiang Zhang;Yawei Yu;Ruijie Xu;Qingfang Zheng;Ping Zhang; Apparue dans: IEEE Journal on Selected Areas in Communications Date publication: 08.-2017, volume: 35, issue:8, pages: 1887 - 1903 Editeur: IEEE Document complet vers site de l'éditeur
» 3-D Nonlinear Acoustic Inverse Scattering: Algorithm and Quantitative Results
 Résumé:We describe a novel 3-D ultrasound technology, the quantitative transmission ultrasound system and algorithm to image a pendent breast in a water bath. Quantitative accuracy is verified using phantoms. Morphological accuracy is verified using cadaveric breast and in vivo images, and spatial resolution is estimated. This paper generalizes an earlier 2-D algorithm to a full 3-D inversion algorithm and shows the importance of such a 3-D algorithm for artifact suppression as compared with the 2-D algorithm. The resultant high-resolution ultrasound images, along with quantitative information regarding tissue speed of sound/stiffness, provide a more accurate depiction of the breast anatomy and lesions, contributing to improved breast care. Auteurs: J. W. Wiskin;D. T. Borup;E. Iuanow;J. Klock;Mark W. Lenox; Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Date publication: 08.-2017, volume: 64, issue:8, pages: 1161 - 1174 Editeur: IEEE Document complet vers site de l'éditeur
» 4-D Reconstruction With Respiratory Correction for Gated Myocardial Perfusion SPECT
 Résumé:Cardiac single photon emission computed tomography (SPECT) images are known to suffer from both cardiac and respiratory motion blur. In this paper, we investigate a 4-D reconstruction approach to suppress the effect of respiratory motion in gated cardiac SPECT imaging. In this approach, the sequence of cardiac gated images is reconstructed with respect to a reference respiratory amplitude bin in the respiratory cycle. To combat the challenge of inherent high-imaging noise, we utilize the data counts acquired during the entire respiratory cycle by making use of a motion-compensated scheme, in which both cardiac motion and respiratory motion are taken into account. In the experiments, we first use Monte Carlo simulated imaging data, wherein the ground truth is known for quantitative comparison. We then demonstrate the proposed approach on eight sets of clinical acquisitions, in which the subjects exhibit different degrees of respiratory motion blur. The quantitative evaluation results show that the 4-D reconstruction with respiratory correction could effectively reduce the effect of motion blur and lead to a more accurate reconstruction of the myocardium. The mean-squared error of the myocardium is reduced by 22%, and the left ventricle (LV) resolution is improved by 21%. Such improvement is also demonstrated with the clinical acquisitions, where the motion blur is markedly improved in the reconstructed LV wall and blood pool. The proposed approach is also noted to be effective on correcting the spill-over effect in the myocardium from nearby bowel or liver activities. Auteurs: Wenyuan Qi;Yongyi Yang;Chao Song;Miles N. Wernick;P. Hendrik Pretorius;Michael A. King; Apparue dans: IEEE Transactions on Medical Imaging Date publication: 08.-2017, volume: 36, issue:8, pages: 1626 - 1635 Editeur: IEEE Document complet vers site de l'éditeur
» 94-GHz Compact 2-D Multibeam LTCC Antenna Based on Multifolded SIW Beam-Forming Network
 Résumé:This communication presents a compact 94-GHz 2-D multibeam antenna using the low-temperature co-fired ceramic (LTCC) technology. A good 2-D substrate integrated waveguide (SIW) beam-forming network (BFN) for eight beams is proposed, where four-phase shifters are properly introduced to increase the flexibility of the beams. Benefiting from multilayer LTCC, the BFN is compactly implemented in a completely symmetrical structure by using two multifolded SIW Butler matrixes with 50% reduction of the longitudinal size, and four couplers placed on different layers with interlaced signal routes to avoid overlaps or crossovers. Combined with a $2 \times 4$ SIW slot antenna array, the multibeam antenna can realize eight symmetric scanning beams on 2-D with stable gains for a wide coverage. For demonstration, the two single-port antennas with different pitch-angle beams are fabricated and measured, and good agreements with the expectations are observed. The differences of the beam orientations are less than 5°, while the measured peak gains of the beams are about 8.5 dBi. Auteurs: Wanchen Yang;Yayang Yang;Wenquan Che;Chong Fan;Quan Xue; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 08.-2017, volume: 65, issue:8, pages: 4328 - 4333 Editeur: IEEE Document complet vers site de l'éditeur
» π Model AC–AC Converter With Controllable Phase and Amplitude
 Résumé:Based on cascaded ac–ac converter with controllable phase and amplitude (ACCPA), a novel π model ACCPA was proposed for power flow control, whose output voltage phase and amplitude can be regulated, respectively, and simultaneously with respect to the input voltage. Single-phase π model ACCPA comprises a buck-type ac unit, a third harmonic trap and a boost-type ac converter. Compared with single-phase cascaded ACCPA, it has a more simplified structure by dispensing with the LC output filter of the buck-type ac converter, and can adopt the same two-stage duty-cycle modulation. The buck-type ac unit regulates the phase of output voltage and the boost-type ac converter does the amplitude. By utilizing impedance compensation with capacitance in single-phase π model ACCPA, it is effective to counteract or reduce the lag effect which is put on fundamental voltage by line impedance of third harmonic trap and inductance. Three-phase π model ACCPA comprises three buck-type ac units and a three-phase boost-type ac converter, it not only dispenses with three LC output filters, but also does three third harmonic traps, so it has simple structure. Experimental results verified the feasibility of π model ACCPA and the correctness of its theory. Auteurs: Youjun Zhang;Xinbo Ruan; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 08.-2017, volume: 64, issue:8, pages: 6422 - 6431 Editeur: IEEE Document complet vers site de l'éditeur
» In Situ Growth of Al2O3 as a Passivation and Antireflection Layer on TiO2-Based MSM Photodetectors
 Résumé:The in situ growth of Al2O3 on TiO2 by ultrasonic spray pyrolysis deposition is presented in this paper. Here, Al2O3 is used as the passivation and the antireflection layer. TiO2-based photodetectors (PDs) with Al2O3, SiO2, and no passivation layers were studied. It was found that the PD without the passivation layer has the highest dark current and photocurrent due to high internal photoconductive gain related to the reaction between the oxygen molecule and TiO2. The PDs with Al2O3 and SiO2 passivation layers suppress the internal photoconductive gain and show stable $I$ – $V$ characteristics after the PDs are exposed to air for 30 days. The device with the Al2O3 passivation layer showed the most stable $I$ – $V$ characteristics and the highest detectivity and the shortest response time among the three devices. Auteurs: Han-Yin Liu;Guan-Jyun Liu;Ruei-Chin Huang;Wen-Ching Sun;Sung-Yen Wei;Sheng-Min Yu; Apparue dans: IEEE Sensors Journal Date publication: 08.-2017, volume: 17, issue:16, pages: 5087 - 5092 Editeur: IEEE Document complet vers site de l'éditeur
» ATOM: Efficient Tracking, Monitoring, and Orchestration of Cloud Resources
 Résumé:The emergence of Infrastructure as a Service framework brings new opportunities, which also accompanies with new challenges in auto scaling, resource allocation, and security. A fundamental challenge underpinning these problems is the continuous tracking and monitoring of resource usage in the system. In this paper, we present ATOM, an efficient and effective framework to automatically track, monitor, and orchestrate resource usage in an Infrastructure as a Service (IaaS) system that is widely used in cloud infrastructure. We use novel tracking method to continuously track important system usage metrics with low overhead, and develop a Principal Component Analysis (PCA) based approach to continuously monitor and automatically find anomalies based on the approximated tracking results. We show how to dynamically set the tracking threshold based on the detection results, and further, how to adjust tracking algorithm to ensure its optimality under dynamic workloads. Lastly, when potential anomalies are identified, we use introspection tools to perform memory forensics on VMs guided by analyzed results from tracking and monitoring to identify malicious behavior inside a VM. We demonstrate the extensibility of ATOM through virtual machine (VM) clustering. The performance of our framework is evaluated in an open source IaaS system. Auteurs: Min Du;Feifei Li; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 08.-2017, volume: 28, issue:8, pages: 2172 - 2189 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.038-mm2 SAW-Less Multiband Transceiver Using an N-Path SC Gain Loop
 Résumé:An N-path switched-capacitor (SC) gain loop is proposed as an area-efficient surface acoustic wave-less wireless transceiver (TXR) for multiband TDD communications. Unlike the direct-conversion transmitter (TX: baseband (BB) filter $\to$ I/Q modulation $\to$ PA driver) and receiver (RX: LNA $\to$ I/Q demodulation $\to$ BB Filter) that the functions are arranged in an open-loop style, here the signal amplification, bandpass filtering, and I/Q (de)modulation are unified in a closed-loop formation, being reconfigurable as a TX or RX with a local oscillator (LO)-defined center frequency. The key advantages are the multiband operation capability in the TX mode, and high resilience to out-of-band (OB) blockers in the RX mode. Fabricated in a 65-nm CMOS, the TXR prototype consumes up to 38.4 mW (20 mW) in the TX (RX) mode at the 1.88-GHz long-term evolution (LTE)-band2. The LO-defined center frequency covers >80% of the TDD-LTE bands with neither on-chip inductors nor external input-matching components. By properly injecting (extracting) the signals into (from) the N-path SC gain loop, the TX mode achieves an −1 dBm output power, a −40 dBc ACLREUTRA1, and a 2% EVM at 1.88 GHz, while showing a −154.5 dBc/Hz OB noise at 80-MHz offset. In the RX mode, a 3.2-dB noise figure and a +8 dBm OB-IIP3 are measured. The active area (0.03 mm2) of the TXR is 24 $\times$ smaller than the state-of-the-art LTE solutions. Auteurs: Gengzhen Qi;Pui-In Mak;Rui P. Martins; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 08.-2017, volume: 52, issue:8, pages: 2055 - 2070 Editeur: IEEE Document complet vers site de l'éditeur
» A 0.9–5.8-GHz Software-Defined Receiver RF Front-End With Transformer-Based Current-Gain Boosting and Harmonic Rejection Calibration
 Résumé:A 0.9–5.8-GHz receiver RF front-end (RFE) integrating a dual-band low-noise transconductance amplifier (LNTA), a passive harmonic-rejection (HR) down-conversion mixer, and an all-digital frequency synthesizer for software-defined radios are presented. A switchable three-coil transformer acting as the interface between the LNTA and the mixer features current-gain boosting in addition to wideband operation. Automatic local oscillator phase-error detection and calibration circuitry is implemented for the mixers to achieve high HR ratio (HRR). Fabricated in 65-nm CMOS, the RFE measures the noise figure between 2.9 and 3.8 dB, the third-order input intercept point (IIP3) between −1.6 and −12.8 dBm, the third-order HRR of 81 dB, and the fifth-order HRR of 70 dB, while consuming 66–82 mA from a 1.2-V supply and occupying a chip area of 4.2 mm2. Auteurs: Liang Wu;Alan W. L. Ng;Shiyuan Zheng;Hiu Fai Leung;Yue Chao;Alvin Li;Howard C. Luong; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 08.-2017, volume: 25, issue:8, pages: 2371 - 2382 Editeur: IEEE Document complet vers site de l'éditeur
» A 140-mV Variation-Tolerant Deep Sub-Threshold SRAM in 65-nm CMOS
 Résumé:This paper presents a sub-threshold SRAM, which eliminates bitline (BL) leakage-induced read failures. The proposed architecture clamps the current ratio between differential BLs to a fixed value, thus permitting reliable ultra-low-voltage read-out. A de-multiplexed wordline interleaving scheme is presented to compensate for bitcell area overhead. The interleaving technique achieves 9% reduction in decoder area and 50% reduction in clock load within the decoder. A sense amplifier circuit with reduced sensitivity to process variations is proposed to further enhance the reliability of the differential read-out. Measurement results from a 1-kb SRAM, fabricated in an industrial 65-nm low-power CMOS process, show 13.1-kHz operation at 140 mV, with active read and leakage power figures of 30.5 and 28.1 nW, respectively. Auteurs: Khawar Sarfraz;Jin He;Mansun Chan; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 08.-2017, volume: 52, issue:8, pages: 2215 - 2220 Editeur: IEEE Document complet vers site de l'éditeur
» A 152-GHz OOK Transmitter With 3-dBm Output Power in 65-nm CMOS
 Résumé:A high output power 152 GHz ON–OFF keying transmitter in 65-nm CMOS is presented. The transmitter consists of a high dc-RF efficiency push–push voltage-controlled oscillator followed by a high-speed and high-gain switched-mode power amplifier. The transmitter achieves the highest output power (3 dBm) beyond 140 GHz in silicon process, with high on–off ratio (>39 dB) and high dc-RF efficiency (3.7%). The transmitter could support 10-Gb/s data rate communication with a bit-error rate of less than $10^{-12}$ . Auteurs: Xiangyu Meng;Baoyong Chi;Zhihua Wang; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 08.-2017, volume: 27, issue:8, pages: 748 - 750 Editeur: IEEE Document complet vers site de l'éditeur
» A 160-GHz Radar With Flexible Antenna Used as a Sniffer Probe
 Résumé:In radar measurements, the observed area is limited by the antenna beamwidth, and due to the usually fixed transceiver position, only unhidden targets in a small observation area can be detected. Furthermore, bulky lens dimensions prevent the use of radar systems in constricted surroundings despite the small dimensions of microwave monolithic integrated circuit (MMIC) radars. To avoid this issue, a new system concept for a flexible and low-cost 160-GHz radar sniffer probe is presented. The flexible sniffer probe is an extremely low-loss dielectric waveguide with a dielectric elliptical lens (28 dBi) at the end. The dielectric waveguide has dielectric losses of 4.5 dB/m at 160 GHz and high flexibility, supporting bending radii of 1.5 cm with negligible losses. To feed the dielectric waveguide, a metallic waveguide with a duplexer is used, which is fed by a special MMIC-to-metallic waveguide transition. The proposed system expands the known radar measurement scenarios with new industrial, medical, and security applications. Auteurs: Martin Geiger;Martin Hitzler;Stefan Saulig;Johannes Iberle;Philipp Hügler;Christian Waldschmidt; Apparue dans: IEEE Sensors Journal Date publication: 08.-2017, volume: 17, issue:16, pages: 5104 - 5111 Editeur: IEEE Document complet vers site de l'éditeur
» A 190-GHz VCO With 20.7% Tuning Range Employing an Active Mode Switching Block in a 130 nm SiGe BiCMOS
 Résumé:A voltage controlled oscillator (VCO) incorporating a system of coupled oscillators with two active mode switching (AMS) blocks is presented. The AMS blocks excite the main VCOs to operate in two distinct frequency bands. An overlap between the two frequency bands has extended the tuning range of the VCO. By turning the AMS blocks off, low-loss and low-capacitance behaviors of these blocks result in wide tuning range and high harmonic output power at high millimeter-wave frequencies. On the other hand, by turning the AMS blocks on, their loss-canceling and capacitance-tuning behaviors yield to higher power and wider tuning range with a lower center frequency. By having sufficient frequency overlap between the two modes, the implemented VCO achieves record tuning range of 20.7% at 190.5 GHz with a maximum output power of –2.1 dBm. This tuning range is significantly higher than reported silicon-based VCOs with center frequencies higher than 120 GHz. Auteurs: Rouzbeh Kananizadeh;Omeed Momeni; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 08.-2017, volume: 52, issue:8, pages: 2094 - 2104 Editeur: IEEE Document complet vers site de l'éditeur
» A 2-GHz Bandwidth, 0.25–1.7 ns True-Time-Delay Element Using a Variable-Order All-Pass Filter Architecture in 0.13 $\mu$ m CMOS
 Résumé:An all-pass filter architecture that can be generalized to high orders, and can be realized using active circuits is proposed. Using this, a compact true-time-delay element with a widely tunable delay and a large delay-bandwidth product (DBW) is demonstrated. This is useful for beamforming and equalization in the lower GHz range where the use of $LC$ or transmission line-based solutions to realize large delays is infeasible. Coarse tuning of delay is realized by changing the filter’s order while keeping the bandwidth constant and fine tuning is implemented by changing the filter’s bandwidth utilizing the delay-bandwidth tradeoff. A test chip fabricated in 0.13 $\mu \text{m}$ CMOS process demonstrates a delay tuning range of 250 ps–1.7-ns, over a bandwidth of 2 GHz, while maintaining a magnitude deviation of ±0.7 dB. The filter achieves a DBW of 3.4 and a delay per unit area of 5.8 $\mathrm {ns/mm^{2}}$ . The filter has a worst case noise figure of 23 dB, and −40 dB intermodulation (IM3) distortion for 37 mVppd inputs. The chip occupies an active area of 0.6 mm2, and dissipates 112 mW–364 mW of power between its minimum and maximum delay settings. Computed radiation pattern with four antennas spaced $\mathrm {\lambda _{fmax}}/2$ apart shows ±90° beam steering off broadside. Auteurs: Imon Mondal;Nagendra Krishnapura; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 08.-2017, volume: 52, issue:8, pages: 2180 - 2193 Editeur: IEEE Document complet vers site de l'éditeur
» A 2.4-GHz 6.4-mW Fractional-N Inductorless RF Synthesizer
 Résumé:A cascaded synthesizer architecture incorporates a digital delay-line-based filter and an analog noise trap to suppress the quantization noise of the $\Sigma \Delta$ modulator. Operating with a reference frequency of 22.6 MHz, the synthesizer achieves a bandwidth of 10 MHz in the first loop and 12 MHz in the second, heavily suppressing the phase noise of its constituent ring oscillators. Realized in 45-nm digital CMOS technology, the synthesizer exhibits an in-band phase noise of −109 dBc/Hz and an integrated jitter of 1.68 psrms. Auteurs: Long Kong;Behzad Razavi; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 08.-2017, volume: 52, issue:8, pages: 2117 - 2127 Editeur: IEEE Document complet vers site de l'éditeur
» A 2.4-GHz High Conversion Gain Passive Mixer Using $Q$ -Boosted $\pi$ -Type LCL Matching Networks in 90-nm CMOS
 Résumé:In this letter, a 2.4-GHz double-balanced passive mixer is presented which offers high conversion gain. The improvement of the local oscillator (LO) and RF input voltage is obtained as a ${Q}$ -factor by the LC resonance of the $\pi$ -type inductor-capacitor-inductor matching network. This passive mixer with a high conversion gain is fabricated using 90-nm-1P5M CMOS technology. The mixer down converts a 2.4-GHz RF frequency to an intermediate frequency of 10 MHz. The measurement results show a 6.5-dB voltage conversion gain, a −6 dBm 1-dB compression point when LO power is −5 dBm and zero dc power consumption. Auteurs: Hyun-Myung Oh;Jae-Sun Kim;Jeong-Taek Lim;Choul-Young Kim; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 08.-2017, volume: 27, issue:8, pages: 736 - 738 Editeur: IEEE Document complet vers site de l'éditeur
» A 25 GS/s 6b TI Two-Stage Multi-Bit Search ADC With Soft-Decision Selection Algorithm in 65 nm CMOS
 Résumé:While high-speed analog-to-digital converter (ADC) front-ends in serial link receivers enable flexible and powerful digital signal processing-based (DSP-based) equalization, the robustness and power consumption of these ADCs can limit overall receiver energy efficiency. This paper presents a 25 GS/s 6b 8-way time-interleaved multi-bit search ADC that employs a soft-decision selection algorithm to relax track-and-hold (T/H) settling requirements and improve ADC metastability tolerance. T/H bandwidth is also improved with a new shared-input double-tail three-latch structure. Fabricated in general purpose 65 nm CMOS, the ADC occupies 0.24 mm2 total area. A signal-to-noise and distortion ratio (SNDR) of 29.6 dB is achieved at Nyquist while consuming 88 mW from a 1 V supply, translating into a figure-of-merit of 143 fJ/conversion step. A measured <10 $^{-10}$ metastability error rate demonstrates the effectiveness of the soft-decision selection algorithm. Auteurs: Shengchang Cai;Ehsan Zhian Tabasy;Ayman Shafik;Shiva Kiran;Sebastian Hoyos;Samuel Palermo; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 08.-2017, volume: 52, issue:8, pages: 2168 - 2179 Editeur: IEEE Document complet vers site de l'éditeur
» A 29.5 dBm Class-E Outphasing RF Power Amplifier With Efficiency and Output Power Enhancement Circuits in 45nm CMOS
 Résumé:A CMOS class-E outphasing RF power amplifier is presented with a new passive combining circuit that provides high efficiency and high output power. An efficiency enhancement circuit and a power enhancement circuit are proposed as part of the combiner that improve efficiency at power back-off and increase output power without violating reliability limits, respectively. The proposed power amplifier is designed in a 45nm CMOS technology. The power amplifier (PA) delivers 29.5 dBm peak output power at 2.4 GHz with 46.76% drain efficiency at peak output power, 32.96% drain efficiency at 3 dB power back-off, and 21.16% drain efficiency at 6 dB power back-off. The proposed power amplifier shows excellent linearity with digital pre-distortion. Better than −50 dBc adjacent channel power ratio (ACPR) is obtained with 64-QAM long-term evolution (LTE) signal with 10 MHz and 20 MHz bandwidth. For two-carrier 20 MHz LTE signal, −44 dBc ACPR is achieved. 21% average drain efficiency is obtained with LTE signal with a 6 dB peak-to-average power ratio. The PA is also tested with 802.11g WLAN signal and it satisfies the spectral mask requirement with high margin. 1.4% (−37.1 dB) error vector magnitude (EVM) is obtained with LTE signal (64-QAM) with a 10 MHz bandwidth. Auteurs: Aritra Banerjee;Rahmi Hezar;Lei Ding;Baher Haroun; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 08.-2017, volume: 64, issue:8, pages: 1977 - 1988 Editeur: IEEE Document complet vers site de l'éditeur
» A 32 $\times$ 32 ISFET Chemical Sensing Array With Integrated Trapped Charge and Gain Compensation
 Résumé:This paper presents a CMOS-based $32\times 32$ ion-sensitive field-effect transistor (ISFET) system-on-chip for real-time ion imaging. Fabricated in an unmodified 0.35- $\mu \text{m}$ CMOS technology, the ISFET sensor array is based on a pixel topology, which uses capacitive feedback to improve signal attenuation due to passivation capacitance and a low-leakage floating-gate reset followed by a digital correlated double sampling to robustly remove unwanted trapped charge-induced dc offset. An automatic gain calibration (AGC) is used to perform real-time calibration and guarantee all sensors that have the same gain with a 99% accuracy, and combining all these mechanisms guarantees an average pixel voltage variation of 14.3 mV after gain is applied when measured over multiple dies. The full array is experimentally shown to be capable of real-time ion imaging of pH, with an intrinsic sensitivity of 39.6mV/pH and a scan rate of 9.3 frames/s when running the AGC, with a total power consumption of 10.2 mW. Auteurs: Yuanqi Hu;Nicolas Moser;Pantelis Georgiou; Apparue dans: IEEE Sensors Journal Date publication: 08.-2017, volume: 17, issue:16, pages: 5276 - 5284 Editeur: IEEE Document complet vers site de l'éditeur
» A 32 $\times$ 32 ISFET Chemical Sensing Array With Integrated Trapped Charge and Gain Compensation
 Résumé:This paper presents a CMOS-based $32\times 32$ ion-sensitive field-effect transistor (ISFET) system-on-chip for real-time ion imaging. Fabricated in an unmodified 0.35- $\mu \text{m}$ CMOS technology, the ISFET sensor array is based on a pixel topology, which uses capacitive feedback to improve signal attenuation due to passivation capacitance and a low-leakage floating-gate reset followed by a digital correlated double sampling to robustly remove unwanted trapped charge-induced dc offset. An automatic gain calibration (AGC) is used to perform real-time calibration and guarantee all sensors that have the same gain with a 99% accuracy, and combining all these mechanisms guarantees an average pixel voltage variation of 14.3 mV after gain is applied when measured over multiple dies. The full array is experimentally shown to be capable of real-time ion imaging of pH, with an intrinsic sensitivity of 39.6mV/pH and a scan rate of 9.3 frames/s when running the AGC, with a total power consumption of 10.2 mW. Auteurs: Yuanqi Hu;Nicolas Moser;Pantelis Georgiou; Apparue dans: IEEE Sensors Journal Date publication: 08.-2017, volume: 17, issue:16, pages: 5276 - 5284 Editeur: IEEE Document complet vers site de l'éditeur
» A 32 $\times$ 32 ISFET Chemical Sensing Array With Integrated Trapped Charge and Gain Compensation
 Résumé:This paper presents a CMOS-based $32\times 32$ ion-sensitive field-effect transistor (ISFET) system-on-chip for real-time ion imaging. Fabricated in an unmodified 0.35- $\mu \text{m}$ CMOS technology, the ISFET sensor array is based on a pixel topology, which uses capacitive feedback to improve signal attenuation due to passivation capacitance and a low-leakage floating-gate reset followed by a digital correlated double sampling to robustly remove unwanted trapped charge-induced dc offset. An automatic gain calibration (AGC) is used to perform real-time calibration and guarantee all sensors that have the same gain with a 99% accuracy, and combining all these mechanisms guarantees an average pixel voltage variation of 14.3 mV after gain is applied when measured over multiple dies. The full array is experimentally shown to be capable of real-time ion imaging of pH, with an intrinsic sensitivity of 39.6mV/pH and a scan rate of 9.3 frames/s when running the AGC, with a total power consumption of 10.2 mW. Auteurs: Yuanqi Hu;Nicolas Moser;Pantelis Georgiou; Apparue dans: IEEE Sensors Journal Date publication: 08.-2017, volume: 17, issue:16, pages: 5276 - 5284 Editeur: IEEE Document complet vers site de l'éditeur
» A 35-dBm OIP3 CMOS Constant Bandwidth PGA With Extended Input Range and Improved Common-Mode Rejection
 Résumé:An improved CMOS second generation current conveyor with adaptive control circuit (ACC) is proposed, and is used to build a highly linear transconductance–transimpedance programmable gain amplifier (PGA). This PGA is fabricated in a 0.18- $\mu \text{m}$ CMOS technology and draws a 0.58-mA current from a supply of 1.8 V. It achieves a 0–14-dB-gain range within a roughly constant bandwidth of 30 MHz when driving a capacitor load of 2 pF. Enhanced linearity, extended input range, and improved common-mode rejection are achieved due to the employ of the proposed ACC. In addition, gain peaking is less prone to appear as the proposed ACC contributes a significant reduction in ${X}$ terminal parasitic capacitance. Auteurs: Chunfeng Bai;Jianhui Wu;Chao Chen;Xiaoying Deng; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 08.-2017, volume: 64, issue:8, pages: 922 - 926 Editeur: IEEE Document complet vers site de l'éditeur
» A 4-M Pixel High Dynamic Range, Low-Noise CMOS Image Sensor With Low-Power Counting ADC
 Résumé:In this paper, we present a 4-Mpixel high dynamic range (DR), low dark noise CMOS image sensor. The pixel design is based on a 4-T PPD structure, with one dedicated High Dynamic Range transistor added in serial with the reset transistor for changing the conversion factor during readout to enhance the DR. A low-power ramp counting Analog to Digital Convertor array is implemented to suppress the structure noise and decrease the power consumption. Measurement results show that when the sensor is operated at a full speed of 47 fps, DR of 87 dB, and dark noise of less than 2e− can be achieved. Also the proposed low-power counting method has a dramatic reduction in the current consumed by the column counters during the ADC operation compared with previous documented methods. Auteurs: Cheng Ma;Yang Liu;Yang Li;Quan Zhou;Xinyang Wang;Yuchun Chang; Apparue dans: IEEE Transactions on Electron Devices Date publication: 08.-2017, volume: 64, issue:8, pages: 3199 - 3205 Editeur: IEEE Document complet vers site de l'éditeur
» A 50-mA 99.2% Peak Current Efficiency, 250-ns Settling Time Digital Low-Dropout Regulator With Transient Enhanced PI Controller
 Résumé:A fully integrated digital low-dropout regulator (DLDO) with a fast transient response, providing a regulated supply for system-on-chip (SoC) power management applications is proposed. Wideband operation and fast transient response are achieved through a transient enhanced proportional-integral controller, without compromising the stability of the DLDO at steady-state operation. The transient enhancement stage boosts loop-gain dynamically during load transients. In the gain boosting mode, the DLDO closed-loop bandwidth is increased, resulting in reduced undershoot/overshoot and fast settling. When the output voltage recovers to the desired level, the boost mode operation is disabled. For a load change with a 4-mA/ns slew rate between 10 and 50 mA, utilizing transient enhancement mode reduced the measured undershoot and overshoot by 35% and 17%, respectively. The characterization results show that the transient enhancement mode can reduce the settling time from 500 to 250 ns for a 10–50-mA load current change. The proposed DLDO operates with an input voltage ranging from 0.84 to 1.24 V, and output voltage ranging from 0.6 to 1 V. The maximum output current of the DLDO is 50 mA and the DLDO achieves a peak current efficiency of 99.2%, with DLDO figure of merit (FOM2) of 63.25 ps. The DLDO prototype chip is fabricated on a 0.13- $\mu \text{m}$ CMOS technology and occupies a 0.0631-mm2 die area. Auteurs: ChaiYong Lim;Debashis Mandal;Bertan Bakkaloglu;Sayfe Kiaei; Apparue dans: IEEE Transactions on Very Large Scale Integration Systems Date publication: 08.-2017, volume: 25, issue:8, pages: 2360 - 2370 Editeur: IEEE Document complet vers site de l'éditeur
» A 60-GHz Coplanar Waveguide-Based Bidirectional LNA in SiGe BiCMOS
 Résumé:A bidirectional low-noise amplifier (LNA) is presented in this letter. By using transistor bias control and low-loss coplanar waveguide structures with defected ground shield as both interconnect traces and distributed passives, the proposed two-port bidirectional amplifier achieves a measured performance close to the stand-alone LNA from 54 to 65 GHz. The design is fabricated in a 0.18- $\mu \text{m}$ SiGe BiCMOS process consuming a maximum 10.6-mA current from a 1.8-V supply voltage and occupies a 0.85-mm2 core die area. Auteurs: Thangarasu Bharatha Kumar;Kaixue Ma;Kiat Seng Yeo; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 08.-2017, volume: 27, issue:8, pages: 742 - 744 Editeur: IEEE Document complet vers site de l'éditeur
» A 7.8-mW 5-b 5-GS/s Dual-Edges-Triggered Time-Based Flash ADC
 Résumé:This paper proposes a 5-b 5-GS/s time-based flash ADC in 65-nm digital CMOS technology, which utilizes both rising and falling edges of the clock for sampling and quantization. A dual-edge-triggered scheme reduces the dynamic power consumption of a voltage-to-time converter and the clock buffers by half. We doubled both the reset and the available regeneration times by interleaving the time comparators. The ADC has a low input capacitance and the calibration circuit is included on-chip for suppressing various mismatches. The prototype running at 5 GS/s consumes 7.8 mW from a 1-V supply and achieves a signal-to-noise and distortion ratio of 26.19 dB at Nyquist. The resulting figure of merit is 94.6 fJ/conversion-step and the core area is only 0.004 mm2. Auteurs: Chi-Hang Chan;Yan Zhu;Sai-Weng Sin;U. Seng-Pan;Rui P. Martins;Franco Maloberti; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 08.-2017, volume: 64, issue:8, pages: 1966 - 1976 Editeur: IEEE Document complet vers site de l'éditeur
» A Backprojection-Based Imaging for Circular Synthetic Aperture Radar
 Résumé:Circular synthetic aperture radar (CSAR) has attracted much attention in the field of high-resolution SAR imaging. However, the CSAR image focusing is affected by the motion deviations of platform. In the processing of experimental CSAR data to deal with motion errors, the main way is using setup calibrators, which restricts its widespread applications. In this paper, based on the estimation of motion errors, an autofocus CSAR imaging strategy is proposed without using any setup calibrator. The first step is to split the entire aperture into several subapertures, the second step is to process the data in subapertures with an autofocus backprojection method, and the last step is to obtain the final CSAR image by merging the subimages obtained from the subaperture processing. The CSAR data processing results prove that the proposed strategy can remove the motion errors accurately and acquire well-focused CSAR images. Auteurs: Leping Chen;Daoxiang An;Xiaotao Huang; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 08.-2017, volume: 10, issue:8, pages: 3547 - 3555 Editeur: IEEE Document complet vers site de l'éditeur
» A Backstepping Approach to Decentralized Active Disturbance Rejection Control of Interacting Boost Converters
 Résumé:In this paper, the local trajectory tracking control problems ascribed to two interacting plants, considered as agents, are formulated as adaptive control problems, which involve online interaction estimation and interaction elimination. This approach gives rise to a robust decentralized collaborative control with virtually no information on the part of the agents. It is shown that when the interconnection effects are viewed as exogenous unstructured disturbances, such disturbance can be actively estimated and canceled from each individual subsystem model dynamics. The case presented deals with two agents, two interconnected boost dc–dc power converters, powered each one by a nonidentical photovoltaic module that represents a time-varying power supply. Then, a backstepping-based control together with an extended state observer is developed by each agent. The mutual goals of agents are to maintain a desired behavior (time-varying current demand) of the entire system in order to maintain the desired output voltage value and an equitable current sharing in each converter in order to supply a dc motor. The proposed distributed control technique is implemented in two TMS320F28335 digital signal processor (each one per agent) and its performance is experimentally evaluated in real time. It is shown that the proposed scheme is robust with respect to interaction, unmodeled nonlinearities, and unmodeled dynamics. Auteurs: Arturo Hernández-Méndez;Jesús Linares-Flores;Hebertt Sira-Ramírez;Jóse F. Guerrero-Castellanos;Gerardo Mino-Aguilar; Apparue dans: IEEE Transactions on Industry Applications Date publication: 08.-2017, volume: 53, issue:4, pages: 4063 - 4072 Editeur: IEEE Document complet vers site de l'éditeur
» A BCI-Based Environmental Control System for Patients With Severe Spinal Cord Injuries
 Résumé:Objective: This study proposes an event-related potential (ERP) brain-computer interface (BCI)-based environmental control system that integrates household electrical appliances, a nursing bed, and an intelligent wheelchair to provide daily assistance to paralyzed patients with severe spinal cord injuries (SCIs). Methods: An asynchronous mode is used to switch the environmental control system on or off or to select a device (e.g., a TV) for achieving self-paced control. In the asynchronous mode, we introduce several pseudo-keys and a verification mechanism to effectively reduce the false operation rate. By contrast, when the user selects a function of the device (e.g., a TV channel), a synchronous mode is used to improve the accuracy and speed of BCI detection. Two experiments involving six SCI patients were conducted separately in a nursing bed and a wheelchair, and the patients were instructed to control the nursing bed, the wheelchair, and household electrical appliances (an electric light, an air conditioner, and a TV). Results: The average false rate of BCI commands in the control state was 10.4%, whereas the average false operation ratio was 4.9% (a false BCI command might not necessarily results in a false operation according to our system design). During the idle state, there was an average of 0.97 false positives/min, which did not result in any false operations. Conclusion: All SCI patients could use the proposed ERP BCI-based environmental control system satisfactorily. Significance: The proposed ERP-based environmental control system could be used to assist patients with severe SCIs in their daily lives. Auteurs: Rui Zhang;Qihong Wang;Kai Li;Shenghong He;Si Qin;Zhenghui Feng;Yang Chen;Pingxia Song;Tingyan Yang;Yuandong Zhang;Zhuliang Yu;Yaohua Hu;Ming Shao;Yuanqing Li; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 08.-2017, volume: 64, issue:8, pages: 1959 - 1971 Editeur: IEEE Document complet vers site de l'éditeur
» A Biquadratic Cell Based on the Flipped-Source-Follower Circuit
 Résumé:This brief presents a novel biquadratic cell (biquad) based on the flipped-source-follower (FSF) circuit. The main idea is to exploit the FSF circuit as a basic building block for a low-pass second-order filter, taking advantage of its well-known strengths, like low-output impedance, low-noise, large in-band linearity, and low power. Thanks to the very essential FSF circuit, the resulting biquad is a power-efficient broad bandwidth stage, with very low-noise performance. In order to validate the biquad design idea, extensive circuital simulation results will be presented. The filter design example synthesizes a third-order low-pass transfer function and consumes 2.3 mW from a single 1.8 $\text{V} {@} {V} _{\text{DD}}$ . Input noise spectral density is 7 nV/vHz. Linearity has been evaluated in terms of IIP3 (25 dBm) and THD (−40 dBc at 380 ${\text{mV}}_{\text {0-PEAK}}$ output voltage swing, resulting in 62-dB SNR). Hence, a very promising figure-of-merit (i.e., 165 $\text{J}^{{-1}}$ ) has been achieved. Auteurs: Marcello De Matteis;Andrea Baschirotto; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 08.-2017, volume: 64, issue:8, pages: 867 - 871 Editeur: IEEE Document complet vers site de l'éditeur
» A Broad Range of Speed Control of a Permanent Magnet Synchronous Motor Driven by a Modular Multilevel TSBC Converter
 Résumé:This paper provides a theoretical and experimental discussion on a modular multilevel triple-star bridge-cell converter with focus on mitigating the capacitor-voltage fluctuation contained in each bridge cell. A new control method proposed in this paper is characterized by properly superimposing both common-mode voltage and circulating currents in the whole speed range. Moreover, this paper optimizes the amplitude and frequency of the superimposed common-mode voltage on the basis of theoretical analysis, thus resulting in minimizing the voltage fluctuation. The optimized control method makes both voltage fluctuation and cluster-current amplitude smaller than do the existing methods. Experimental waveforms obtained from a three-phase downscaled system using a 370-V, 15-kW, 75-Hz, six-pole, permanent-magnet synchronous motor verify good start-up performance from a standstill to the rated speed, keeping both capacitor-voltage and cluster current within acceptable levels. Auteurs: Wataru Kawamura;Yuto Chiba;Hirofumi Akagi; Apparue dans: IEEE Transactions on Industry Applications Date publication: 08.-2017, volume: 53, issue:4, pages: 3821 - 3830 Editeur: IEEE Document complet vers site de l'éditeur
» A Broadband High-Efficiency Reconfigurable Reflectarray Antenna Using Mechanically Rotational Elements
 Résumé:Design of a circularly polarized reconfigurable reflectarray antenna (RRA) at X band is presented. The RRA element employs concentric dual split rings, and can be mechanically rotated to obtain continuous 360° phase coverage with negligible element loss. A prototype with $15\times15$ manually rotated elements is first computed, simulated, and measured. Full-wave simulations show that the gain of the beam focused in ( $\theta =20^{\circ }$ , $\varphi = 0^{\circ }$ ) direction is 25.8 dB and the 1-dB gain bandwidth is over 28.6%. The measured results show that the beam at ( $\theta = 20^{\circ }$ , $\varphi = 0^{\circ }$ ) direction achieves the maximum gain of 25.6 dB, corresponding to an aperture efficiency of 51.8%. The beam-steering capability of the RRA is measured within ±60° angular range, and well-defined scanned beams are obtained with maximum scan loss of 3.7 dB. The versatile beam-forming capability of the RRA is also verified by synthesizing a square shaped beam and a cosecant shaped beam. Another micromotor-controlled prototype with 756 elements on an octagonal aperture is fabricated and its measured radiation performance validates the feasibility of the proposed design as well. Auteurs: Xue Yang;Shenheng Xu;Fan Yang;Maokun Li;Yangqing Hou;Shuidong Jiang;Lei Liu; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 08.-2017, volume: 65, issue:8, pages: 3959 - 3966 Editeur: IEEE Document complet vers site de l'éditeur
» A Calculation Framework for Quantifying the Probability of Ventricular Fibrillation of Rare Events
 Résumé:This paper outlines a novel method for calculating the probability that an individual exposed to an electrical hazard will experience ventricular fibrillation (v.f.) as a result. This method was developed to deal with high-impact low-likelihood (HILL) events where a minute percentage of the population is exposed to, or is susceptible to, the hazards created by the event. The consequences of a HILL event can be extreme, for example, death, but effective management of HILL events is a quandary for society since the likelihood of the extreme outcome is low. The framework presented here was developed to analyze and manage electrical hazards associated with ground potential rise during power system faults. It can, however, be applied to other events involving infrequent exposure of small percentages of the population to electrical hazards. Where electrical hazards occur as HILL events, the range of sensitivity in the population becomes critical so it is necessary to ensure that the more extreme individuals are explicitly considered. Most commonly used methods for estimating complex probabilities (for example, Monte-Carlo) are poorly suited to this application as they focus on the behavior of the “bulk” of probability distributions rather than characterizing the tails. The method outlined facilitates deliberate consideration of the complete range of sensitivities to electricity demonstrated by the human population. It also has the additional benefit of significantly reduced computational requirements while remaining intuitive in application. The validity of the method is confirmed by reproducing previous work investigating the probability of v.f. of step voltages using the safety criteria outlined in IEEE standard 80. Auteurs: Ian Griffiths;Darren J. Woodhouse; Apparue dans: IEEE Transactions on Power Delivery Date publication: 08.-2017, volume: 32, issue:4, pages: 2052 - 2059 Editeur: IEEE Document complet vers site de l'éditeur
» A Capacitated Vehicle Routing Problem With Synchronized Pick-Ups and Drop-Offs: The Case of Medication Delivery and Supervision in the DR Congo
 Résumé:In postemergency contexts such as the Democratic Republic of Congo (DR Congo), one of the crucial challenges that rural hospitals face is maintaining a pharmacy with essential medications and supplies. There is a negative humanitarian impact when hospitals do not have medications for treatable diseases; hospitals incur financial losses when too much medication is ordered and expires. Moreover, the cost of transporting medications and providing on-site supervision to remote hospitals is an extremely expensive endeavor. Sometimes, the transportation costs can exceed the cost of the medications. Using as a case study, the province of Bandundu, in the DR Congo, we attempt to determine the feasibility (in terms of problem complexity and potential savings) of a synchronized routing problem for medication delivery and on-site supervision visits. We propose a capacitated vehicle routing problem formulation handling several novel requirements: activity-wise synchronization, precedence, and two activity frequencies. We implement a new heuristic procedure with a geospatially enabled database to solve the problem. Administrators can use a web-based tool to view the results as interactive maps. Preliminary results suggest that a synchronized solution allows rural hospitals to increase accessibility to medical services to rural populations by increasing delivery frequencies from 4 months to 1 month. Auteurs: John Clarke;Viviane Gascon;Jacques A. Ferland; Apparue dans: IEEE Transactions on Engineering Management Date publication: 08.-2017, volume: 64, issue:3, pages: 327 - 336 Editeur: IEEE Document complet vers site de l'éditeur
» A Circularly Polarized High-Gain Antenna With Low RCS Over a Wideband Using Chessboard Polarization Conversion Metasurfaces
 Résumé:A new approach for the gain enhancement and wideband radar cross section (RCS) reduction of an antenna based on the chessboard polarization conversion metasurfaces (CPCMs) is proposed. Compared with the previous low-RCS antennas, high gain and wideband low RCS of a circularly polarized (CP) antenna are achieved simultaneously. The proposed CPCM is the chessboard configuration of the polarization conversion metasurfaces (PCMs), which is made up of adjoining two-layer substrates with three metallic patterns. Low RCS is realized by 180° (±30°) reflection phase variations between two neighboring PCMs. Gain enhancement is achieved by employing a Fabry-Perot cavity, which is constructed by the PCM and the ground of the antenna. The antenna with CPCM operating at the $X$ -band, excited by a sequentially rotated feeding network, is fabricated and measured. Simulated and measured results show that the left-hand CP gain of the antenna with CPCM is at least 3 dB higher than that of the reference antenna from 8.5 to 9.5 GHz and the monostatic RCS is effectively reduced from 6 to 14 GHz. Auteurs: Kun Li;Ying Liu;Yongtao Jia;Y. J. Guo; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 08.-2017, volume: 65, issue:8, pages: 4288 - 4292 Editeur: IEEE Document complet vers site de l'éditeur
» A Circulating-Current Suppression Method for Parallel-Connected Voltage-Source Inverters With Common DC and AC Buses
 Résumé:This paper presents a theoretical study with experimental validation of a circulating-current suppression method for parallel operation of three-phase voltage-source inverters (VSI), which may be suitable for modular parallel uninterruptible power supply systems or hybrid ac/dc microgrid applications. The basic concept of the proposed circulating-current suppression method is to modify the original current references by using the current difference among the parallel inverters. In the proposed approach, both cross circulating current and zero-sequence circulating current are considered, and are added into the conventional droop plus virtual impedance control. In the control architecture, the reference voltages of the inverters are generated by the primary control loop, which consists of a droop control and a virtual impedance. The secondary control is used to compensate the voltage drop on the virtual impedance. Furthermore, a circulating-current control loop is added to improve the average current-sharing performance among parallel VSIs. Experimental results are presented to show the effectiveness of the proposed control method to suppress both cross and zero-sequence circulating currents. Auteurs: Baoze Wei;Josep M. Guerrero;Juan C. Vásquez;Xiaoqiang Guo; Apparue dans: IEEE Transactions on Industry Applications Date publication: 08.-2017, volume: 53, issue:4, pages: 3758 - 3769 Editeur: IEEE Document complet vers site de l'éditeur
» A Closed-Form Solution for the Low-Current Collector Transit Time in Group IV and Group III-V HBTs
 Résumé:In certain types of heterojunction bipolar transistors (HBTs), the carrier transit time associated with the base-collector (BC) space-charge region constitutes a significant contribution to the total transit time. In many compact models, the low-current BC transit time is lumped in with the total low-current transit time and often assumed to be constant—dependent only on the collector width and material saturation velocity. This assumption, however, is insufficient for modeling high-voltage Si-based HBTs as well as for III-V HBTs, where the negative differential mobility (NDM) effect can become relevant in high-speed low-power circuits. This paper presents a closed-form solution for the low-current collector transit time based on a novel accurate analytical velocity-field formulation, covering both group IV and group III-V semiconductor materials. The new solution includes the NDM effect and is suitable for implementation in compact models, and its relevance and accuracy are demonstrated for both TCAD simulated and measured data. Auteurs: Michael Schröter;Tobias Nardmann;Gerald Wedel; Apparue dans: IEEE Transactions on Electron Devices Date publication: 08.-2017, volume: 64, issue:8, pages: 3346 - 3352 Editeur: IEEE Document complet vers site de l'éditeur
» A Coding Theorem for Bipartite Unitaries in Distributed Quantum Computation
 Résumé:We analyze implementations of bipartite unitaries by means of local operations and classical communication (LOCC) assisted by shared entanglement. We employ concepts and techniques developed in the quantum Shannon theory to study an asymptotic scenario, in which two distant parties perform the same bipartite unitary on infinitely many pairs of inputs. We analyze minimum cost of entanglement and classical communication per copy. For two-round LOCC protocols, we derive a single-letter formula for the minimum cost of entanglement and classical communication, under an additional requirement that the error converges to zero faster than $1/n^{4}$ , where $n$ is the number of input pairs. The formula is given by the “Markovianizing cost” of a tripartite state associated with the unitary, which can be computed by a finite-step algorithm. We also derive a lower bound on the minimum cost of resources, which applies for protocols with arbitrary number of rounds. Auteurs: Eyuri Wakakuwa;Akihito Soeda;Mio Murao; Apparue dans: IEEE Transactions on Information Theory Date publication: 08.-2017, volume: 63, issue:8, pages: 5372 - 5403 Editeur: IEEE Document complet vers site de l'éditeur
» A Common Transceiver Design for Nonregenerative Asymmetric and Symmetric Two-Way Relaying With Relaxed Antenna Constraints
 Résumé:We investigate a novel multiple-input multiple-output common transceiver design for conventional symmetric and recently proposed asymmetric two-way relaying (TWR). In conventional symmetric TWR, a user exchanges data with a base station. Both base station and user can cancel back-propagating interference (BI). In asymmetric TWR, the base station performs TWR with two different users—a transmit-only user and a receive-only user, which experiences BI. The existing asymmetric TWR transceiver designs constraints the number of relay antennas to cancel the BI. The proposed transceiver relaxes these antenna constraints and works seamlessly for both asymmetric and symmetric TWR. Furthermore, the design also enables TWR communication between multiple users and a base station. The proposed design is also shown to have lower complexity than the existing designs. For the proposed transceiver, we maximize its sum rate using geometric programming for different TWR scenarios. We demonstrate using exhaustive numerical simulations that the sum-rate of the proposed design not only matches the best known designs in asymmetric and symmetric TWR literature, but also outperforms them for certain antenna configurations. Auteurs: Rohit Budhiraja;Ajit K. Chaturvedi; Apparue dans: IEEE Transactions on Vehicular Technology Date publication: 08.-2017, volume: 66, issue:8, pages: 7026 - 7037 Editeur: IEEE Document complet vers site de l'éditeur
» A Compact Memristor-Based Dynamic Synapse for Spiking Neural Networks
 Résumé:Recent advances in memristor technology lead to the feasibility of large-scale neuromorphic systems by leveraging the similarity between memristor devices and synapses. For instance, memristor cross-point arrays can realize dense synapse network among hundreds of neuron circuits, which is not affordable for traditional implementations. However, little progress was made in synapse designs that support both static and dynamic synaptic properties. In addition, many neuron circuits require signals in specific pulse shape, limiting the scale of system implementation. Last but not least, a bottom-up study starting from realistic memristor devices is still missing in the current research of memristor-based neuromorphic systems. Here, we propose a memristor-based dynamic (MD) synapse design with experiment-calibrated memristor models. The structure obtains both static and dynamic synaptic properties by using one memristor for weight storage and the other as a selector. We overcame the device nonlinearities and demonstrated spike-timing-based recall, weight tunability, and spike-timing-based learning functions on MD synapse. Furthermore, a temporal pattern learning application was investigated to evaluate the use of MD synapses in spiking neural networks, under both spike-timing-dependent plasticity and remote supervised method learning rules. Auteurs: Miao Hu;Yiran Chen;J. Joshua Yang;Yu Wang;Hai Helen Li; Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Date publication: 08.-2017, volume: 36, issue:8, pages: 1353 - 1366 Editeur: IEEE Document complet vers site de l'éditeur
» A Compact Model for the Statistics of the Low-Frequency Noise of MOSFETs With Laterally Uniform Doping
 Résumé:In this paper, we develop a compact physics-based statistical model for random telegraph noise-related low-frequency noise in bulk MOSFETS with laterally uniform doping. The proposed model is suited for modern compact device models, such as PSP, BSIM, and EKV. With our proposed model, one can calculate the expected value and the variability of the noise as a function of bias and device parameters. We validate the model through numerous experimental results from different CMOS nodes, down to 40 nm. Auteurs: Maurício Banaszeski da Silva;Hans P. Tuinhout;Adrie Zegers-van Duijnhoven;Gilson I. Wirth;Andries J. Scholten; Apparue dans: IEEE Transactions on Electron Devices Date publication: 08.-2017, volume: 64, issue:8, pages: 3331 - 3336 Editeur: IEEE Document complet vers site de l'éditeur
» A Compact Short-Channel Model for Symmetric Double-Gate TMDFET in Subthreshold Region
 Résumé:This paper presents a compact analytical ${I}$ – ${V}$ model for short-channel double-gate transition metal dichalcogenide filed-effect transistors in the subthreshold region. A closed-form expression is proposed for the characteristic length in the scale length approach, which is based on physical device parameters. It is then used to find the channel potential and drain current in the subthreshold region. This model is verified with the numerical results of a nonequilibrium Green’s function (NEGF) simulator. There is good agreement between the results of the proposed model and the numerical NEGF simulations in the subthreshold region, while it captures the effects of the device’s physical parameters. Auteurs: Morteza Gholipour; Apparue dans: IEEE Transactions on Electron Devices Date publication: 08.-2017, volume: 64, issue:8, pages: 3466 - 3469 Editeur: IEEE Document complet vers site de l'éditeur
» A Comparative Review of the Methodologies to Identify a Global Earthing System
 Résumé:International Standards IEC 61936-1 and EN 50522 define a global earthing system (GES) as the earthing network, created by the interconnection of local earthing systems that should guarantee the absence of dangerous touch voltages. Despite that, standards do not provide any official practical guidelines for its identification. The official classification of GES areas would lead to a simplification of the design and verification procedures of medium voltage/low voltage (MV/LV) substations grounding systems with associated economical savings for both distribution system operators and MV users. To overcome this regulatory vacuum, several teams of researchers proposed methods to identify the presence of a GES. In this paper, the main methods developed to identify a GES are presented. The different methodologies are applied to a real urban scenario and compared. Auteurs: Pietro Colella;Enrico Pons;Riccardo Tommasini; Apparue dans: IEEE Transactions on Industry Applications Date publication: 08.-2017, volume: 53, issue:4, pages: 3260 - 3267 Editeur: IEEE Document complet vers site de l'éditeur
» A Comparison of Finite Element-Based Inversion Algorithms, Local Frequency Estimation, and Direct Inversion Approach Used in MRE
 Résumé:In quantitative elastography, maps of the mechanical properties of soft tissue, or elastograms, are calculated from the measured displacement data by solving an inverse problem. The model assumptions have a significant effect on elastograms. Motivated by the high sensitivity of imaging results to the model assumptions for in vivo magnetic resonance elastography of the prostate, we compared elastograms obtained with four different methods. Two finite-element method (FEM)-based methods developed by our group were compared with two other commonly used methods, local frequency estimator (LFE) and curl-based direct inversion (c-DI). All the methods assume a linear isotropic elastic model, but the methods vary in their assumptions, such as local homogeneity or incompressibility, and in the specific approach used. We report results using simulations, phantom, and ex vivo and in vivo data. The simulation and phantom studies show, for regions with an inclusion, that the contrast to noise ratio (CNR) for the FEM methods is about three to five times higher than the CNR for the LFE and c-DI and the rms error is about half. The LFE method produces very smooth results (i.e., low CNR) and is fast. c-DI is faster than the FEM methods but it is only accurate in areas where elasticity variations are small. The artifacts resulting from the homogeneity assumption in c-DI is detrimental in regions with large variations. The ex vivo and in vivo results also show similar trends as the simulation and phantom studies. The c-FEM method is more sensitive to noise compared with the mixed-FEM due to higher orders derivatives. This is especially evident at lower frequencies, where the wave curvature is smaller and it is more prone to such error, causing a discrepancy in the absolute values between the mixed-FEM and c-FEM in our in vivo results. In general, the proposed FEMs use fewer simplifyin- assumptions and outperform the other methods but they are computationally more expensive. Auteurs: Mohammad Honarvar;Ramin S. Sahebjavaher;Robert Rohling;Septimiu E. Salcudean; Apparue dans: IEEE Transactions on Medical Imaging Date publication: 08.-2017, volume: 36, issue:8, pages: 1686 - 1698 Editeur: IEEE Document complet vers site de l'éditeur
» A Comprehensive Investigation of a Microfabricated U-Bend Polymer Waveguide With Analyte Micro-Reservoir for Versatile On-Chip Sensing Applications
 Résumé:In our earlier designed, embedded U-shaped-waveguides, due to lower area of analyte interaction, there was always a scope to simplify and modify the device design to improve its evanescent-absorbance sensitivity. To achieve this objective, a simple designed micro-analysis chips consisting of a U-bend waveguide probes coupled microreservoir structure were theoretically and experimentally investigated in this paper. For the fabrication of these microstructures along with fiber-to-waveguide-coupler structures, a single-step micro-fabrication procedure was performed using SU-8 photoresist. Initially, in this paper, using suitable numerical-calculations, we have also focused on the analyzing various physical parameters, which contribute to their sensitivity, which further corroborated with the experimental results. Furthermore, we recognized the effect of cross-coupling phenomenon (between their two straight-arms) to be a reason for lower RI-sensitivity, as well as linear and higher evanescent-absorption-based detection sensitivity for lower bending-diameter (<0.5 mm) waveguide. Compared with embedded U-bend waveguides, the overall evanescent-absorption sensitivity of U-bend waveguides was found improved by approximately three times. Finally, it proved to be a useful flexible sensing-probe for any physical, chemical, and biological sensing application, provided appropriate surface modification is made to this waveguide probe. [2016-0285] Auteurs: Amit Prabhakar;Neha Mishra;Soumyo Mukherji; Apparue dans: Journal of Microelectromechanical Systems Date publication: 08.-2017, volume: 26, issue:4, pages: 935 - 945 Editeur: IEEE Document complet vers site de l'éditeur
» A Comprehensive Theoretical Analysis of Hole Ballistic Velocity in Si, SiGe, and Ge: Effect of Uniaxial Strain, Crystallographic Orientation, Body Thickness, and Gate Architecture
 Résumé:This paper presents a detailed theoretical analysis of the implications of nanoscale device structures on the average hole ballistic velocity calculated from quantum-mechanical strain-dependent $6\times 6~\text {k} \cdot \text {p}$ band-structure simulations. The simulations show that the crystallographic orientation of the uniaxial strain, channel, and surface affect the average ballistic velocity by modifying the energy–momentum (E − k) dispersion of the subbands (from which the ballistic velocity is calculated). Conversely, the analysis shows that semiconductor-body thickness and gate architecture influence the ballistic velocity by modifying the quantum confinement in the structure, which ultimately affects the relative hole occupation of ${k}$ -states across different subbands. Key results of the work show that a 5-nm-body thickness yields a 6%–12% increase in the ballistic velocity compared to a 10-nm body. Likewise, a single-gate architecture gives up to an 11% increase over a double gate, but the improvement is dependent on the crystallographic surface orientation. Strained Ge shows a significantly enhanced ballistic velocity relative to strained Si for both {100}- and {110}-surface orientations with a predicted hole ballistic velocity exceeding $2 \times 10^{7}$ cm/s at $\text{n}_\text{s}^{\text{v+}} = 5 \times 10^{12}$ #/cm2. Auteurs: James T. Teherani; Apparue dans: IEEE Transactions on Electron Devices Date publication: 08.-2017, volume: 64, issue:8, pages: 3316 - 3323 Editeur: IEEE Document complet vers site de l'éditeur
» A Controllably Inductive Filtering Method With Transformer-Integrated Linear Reactor for Power Quality Improvement of Shipboard Power System
 Résumé:This paper proposes a controllably inductive power filtering (CIPF) method to improve the power quality of a shipboard power system (SPS). The main circuit topology for implementing the CIPF method in the SPS is presented, which contains a rectifier transformer integrated with linear filtering reactors, fully tuned branches, and a voltage-source inverter. The characteristic parameters of the rectifier transformer integrated with linear filtering reactors are investigated in detail by theoretical analysis. Furthermore, a mathematical model and an equivalent model are established to reveal the mechanism of harmonic suppression and the advantage of damping harmonic resonance of SPS. Moreover, a coordinated control strategy is designed based on the theoretical analysis. Finally, a detailed case study validates the proposed CIPF method and indicates that this method is suitable for SPS, because it can decrease the installed space and effectively prevent harmonic components from flowing into the generator side (power source), thus resulting in suppressing the vibration and noise pollution of the rectifier transformer. Besides, this method can effectively dampen harmonic resonance caused by the varied short-circuit capacity or the harmonic voltage in SPS. Auteurs: Yong Li;Yanjian Peng;Fang Liu;Denis Sidorov;Daniil Panasetsky;Chonggan Liang;Longfu Luo;Yijia Cao; Apparue dans: IEEE Transactions on Power Delivery Date publication: 08.-2017, volume: 32, issue:4, pages: 1817 - 1827 Editeur: IEEE Document complet vers site de l'éditeur
» A Coordinated Control Approach for DC link and Rotor Crowbars to Improve Fault Ride-Through of DFIG-Based Wind Turbine
 Résumé:Nowadays, most double fed induction generators (DFIGs)-based wind turbines are equipped with a rotor crowbar connected in parallel with the rotor side converter (RSC). The parallel rotor side crowbar (PRSC) is used to protect the RSC and dc-link capacitor by dissipating the rotor energy during grid fault condition. In this paper, two types of crowbar protections are used, one in the rotor winding and the second in the dc link. During the fault condition, the rotor winding crowbar connects in series with the rotor winding and RSC to decrease the RSC current and dissipate the rotor energy. The general PRSC does not have the ability to significantly decrease the over-current. To protect the semiconductor switches of RSC, DFIG should not be kept connected with the utility grids under severe faults. The dc-link capacitor crowbar (DCCC) operates only if the dc capacitor voltage exceeds a threshold level. Both the series rotor side crowbar (SRSC) and the DCCC operate in coordination with each other to protect RSC and dc link during fault condition, and improve the fault ride through of the DFIG. Using the proposed SRSC, RSC continues its operation to control the DFIG during fault condition. Thereby, the reactive power can be injected to support the voltage at the point of common coupling. The behavior of the DFIG is investigated when the combined crowbars are operating with the proposed coordinated control approach and results are presented. Auteurs: Ahmed M. A. Haidar;Kashem M. Muttaqi;Mehrdad Tarafdar Hagh; Apparue dans: IEEE Transactions on Industry Applications Date publication: 08.-2017, volume: 53, issue:4, pages: 4073 - 4086 Editeur: IEEE Document complet vers site de l'éditeur
» A Correction Formula for the ST-Segment Measurements of AC-Coupled Electrocardiograms
 Résumé:Goal: The ST segment of an electrocardiogram (ECG) is very important for the correct diagnosis of an acute myocardial infarction. Most clinical ECGs are recorded using an ACcoupled ECG amplifier. It is well known, that first-order high-pass filters used for the AC coupling can affect the ST segment of an ECG. This effect is stronger the higher the filter's cut-off frequency is and the larger the QRS integral is. We present a formula that estimates these changes in the ST segment and therefore allows for correcting ST measurements that are based on an ACcoupled ECG. Methods:The presented correction formula can be applied when only four parameters are known: the possibly estimated QRS area A, the QRS duration W, the beat-to-beat interval TRR, and the filter time constant T, further, the time point Tj to correct - after the J point - must be specified. Results: The formula is correct within 0.6% until 40ms after the J point and within 6% until 80 ms after the J point. Conclusion and significance: It is not necessary to have the raw data available and the formula therefore opens up the possibility of reevaluating studies that are based on ACcoupled ECGs and compare the results of such studies with studies that are based on newer, DC-coupled ECGs. Auteurs: Ramun Schmid;Jonas L. Isaksen;Remo Leber;Hans-Jakob Schmid;Gianluca Generali;Roger Abächerli; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 08.-2017, volume: 64, issue:8, pages: 1834 - 1840 Editeur: IEEE Document complet vers site de l'éditeur
» A COTS-Based Microwave Imaging System for Breast-Cancer Detection
 Résumé:Microwave imaging is an emerging breast cancer diagnostic technique, which aims at complementing already established methods like mammography, magnetic resonance imaging, and ultrasound. It offers two striking advantages: no-risk for the patient and potential low-cost for national health systems. So far, however, the prototypes developed for validation in labs and clinics used costly lab instruments such as a vector network analyzer (VNA). Moreover, the CPU time required by complex image reconstruction algorithms may not be compatible with the duration of a medical examination. In this paper, both these issues are tackled. Indeed, we present a prototype system based on low-cost and off-the-shelf microwave components, custom-made antennas, and a small form-factor processing system with an embedded field-programmable gate array for accelerating the execution of the imaging algorithm. We show that our low-cost system can compete with an expensive VNA in terms of accuracy, and it is more than 20x faster than a high-performance server at image reconstruction. Auteurs: Mario R. Casu;Marco Vacca;Jorge A. Tobon;Azzurra Pulimeno;Imran Sarwar;Raffaele Solimene;Francesca Vipiana; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 08.-2017, volume: 11, issue:4, pages: 804 - 814 Editeur: IEEE Document complet vers site de l'éditeur
» A Cubature Kalman Filter Based Power System Dynamic State Estimator
 Résumé:This paper proposes an application of the cubature Kalman filter (CKF) to the power system dynamic state estimation (PSDSE) utilizing the measurements from the remote terminal units as well as the phasor measurement units. The CKF process utilizes the spherical cubature and Gaussian quadrature rules to estimate the probability density functions of the state space and the measurement space. This helps in linearization of the nonlinear measurement function without loss of accuracy. The CKF does not require formation of the Jacobian and Hessian matrices to execute the PSDSE, which saves the execution time. A state forecasting technique is utilized to forecast the states during the interval between two time instants of receiving the measurement sets from the field. This helps in estimating the states of the power system during the period when the field measurements are not available. The effectiveness of the application of the CKF to the PSDSE has been demonstrated on IEEE 30 bus system and 246 bus Northern Regional Power Grid Indian system. Auteurs: A. Sharma;S. C. Srivastava;S. Chakrabarti; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 08.-2017, volume: 66, issue:8, pages: 2036 - 2045 Editeur: IEEE Document complet vers site de l'éditeur
» A Data-Driven Method for Trip Ends Identification Using Large-Scale Smartphone-Based GPS Tracking Data
 Résumé:Using tracking data obtained from the smartphone and Internet survey, a data-driven machine learning method is proposed to identify trip ends. In previous literature, this is usually done based on some predefined rules, which have been confirmed to be valid. Nonetheless, these rule-based methods largely depend on researchers’ own knowledge, which is inevitably subjective and arbitrary. Moreover, they are not effective enough to process the huge amount of data in the era of big data. In this paper, millions of smartphone-based GPS tracking data are targeted. A group of attributes, such as travel speed, distance, and heading, are derived to characterize the smartphone holders’ travel status. In other words, the tracking points could be identified as being at the state of traveling or non-traveling, based on which the trip ends are easily detected. In contrast to those rule-based methods, a random forest is utilized in this paper as the classification model, with no subjective rules predefined for classification. This data-driven model is automatically built. The results show that after training the GPS tracking data of 1393 days and the prompted recall (PR) survey data using the random forest, the accuracy of trip ends identification on tracking data of 697 days is 96.17%. The current analysis is free from personal experiences, which is expected to be useful for the smartphone-based survey data in the era of big data. Auteurs: Chaoran Zhou;Hongfei Jia;Zhicai Juan;Xuemei Fu;Guangnian Xiao; Apparue dans: IEEE Transactions on Intelligent Transportation Systems Date publication: 08.-2017, volume: 18, issue:8, pages: 2096 - 2110 Editeur: IEEE Document complet vers site de l'éditeur
» A Decoupled Control Strategy of Modular Multilevel Matrix Converter for Fractional Frequency Transmission System
 Résumé:Fractional frequency transmission system (FFTS), also known as low-frequency ac transmission system, is a promising solution to offshore wind power integration. The ac/ac converter is the most important equipment in FFTS. The modular multilevel matrix converter (M3C) is widely regarded as the next-generation ac/ac converter, but its complex control remains a problem. A novel control strategy is proposed featuring its decoupling algorithm in this paper. Different from previous research, the proposed current control regulates current components of different frequencies separately in star-figure subconverters under their synchronous rotating frames (SRFs), where the current is transformed to dq-axis dc signals for a better performance. A novel algorithm named “cross-SRF decoupling algorithm” is proposed to overcome the tight coupling between the circulating currents of two different frequencies. The effectiveness of the proposed control strategy has been verified by the simulation results obtained from a 110 kV, 400 MW M3C system implemented in MATLAB /Simulink. Auteurs: Shenquan Liu;Xifan Wang;Yongqing Meng;Pengwei Sun;Huiyong Luo;Biyang Wang; Apparue dans: IEEE Transactions on Power Delivery Date publication: 08.-2017, volume: 32, issue:4, pages: 2111 - 2121 Editeur: IEEE Document complet vers site de l'éditeur
» A Design of an Origami Reconfigurable QHA with a Foldable Reflector [Antenna Applications Corner]
 Résumé:This article presents a design of an origami reconfigurable circularly polarized quadrifilar helical antenna (QHA) with a foldable reflector that can operate in K, Ka, and extremely high-frequency (EHF) bands. A 10:1 scale prototype of the proposed antenna is built and validated through measurements and simulations. Auteurs: Xueli Liu;Stavros V. Georgakopoulos;Sudhakar Rao; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 08.-2017, volume: 59, issue:4, pages: 78 - 105 Editeur: IEEE Document complet vers site de l'éditeur
» A Diagonal Subspace-Based Optimization Method for Reconstruction of 2-D Isotropic and Uniaxial Anisotropic Dielectric Objects
 Résumé:In this letter, a diagonal approximation has been introduced in the framework of subspace-based optimization method (SOM), for reducing computational complexity. Due to this approximation, the operator which relates the electric field and equivalent current becomes a diagonal one, instead of the nonlinear one in full-wave inversion. Consequently, the proposed method is named as diagonal SOM (DSOM). Compared with the original SOM, DSOM has a more simplified objective function with much less computational cost. DSOM can be applied for solving inverse scattering problems involving not only isotropic objects, but also uniaxial anisotropic objects, which is demonstrated by numerical examples. Furthermore, DSOM provides reconstruction results that are comparable in quality to the ones obtained using SOM, but with much less computation load. Auteurs: Yulang Liu;Zhiqin Zhao;Xiaozhang Zhu;Wei Yang;Zaiping Nie;Qing-Huo Liu; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 08.-2017, volume: 14, issue:8, pages: 1318 - 1322 Editeur: IEEE Document complet vers site de l'éditeur
» A Diesel-Powered Fuel Cell APU—Reliability Issues and Mitigation Approaches
 Résumé:The paper deals with reliability issues of a diesel-powered fuel cell auxiliary power unit (APU). The unit combines an autothermal diesel reformer and a proton exchange membrane fuel cell stack. The focal point is mitigation approaches for increasing the reliability of the complete APU system. These include control strategies on the one side, and electronic hardware solutions on the other. The measures, guarantying safe, reliable, and long-life operation, were developed, implemented and experimentally validated on a 3-kW net electric power APU system targeted for truck on-board applications. Auteurs: Boštjan Pregelj;Andrej Debenjak;Gregor Dolanc;Janko Petrovčič; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 08.-2017, volume: 64, issue:8, pages: 6660 - 6670 Editeur: IEEE Document complet vers site de l'éditeur
» A Differential Game Approach to Multi-agent Collision Avoidance
 Résumé:A multi-agent system consisting of $N$ agents is considered. The problem of steering each agent from its initial position to a desired goal while avoiding collisions with obstacles and other agents is studied. This problem, referred to as the multi-agent collision avoidance problem, is formulated as a differential game. Dynamic feedback strategies that approximate the feedback Nash equilibrium solutions of the differential game are constructed and it is shown that, provided certain assumptions are satisfied, these guarantee that the agents reach their targets while avoiding collisions. Auteurs: Thulasi Mylvaganam;Mario Sassano;Alessandro Astolfi; Apparue dans: IEEE Transactions on Automatic Control Date publication: 08.-2017, volume: 62, issue:8, pages: 4229 - 4235 Editeur: IEEE Document complet vers site de l'éditeur
» A Digital Frequency Adaptive Synchronization Unit for On- and Off-Grid Systems
 Résumé:This paper presents the analysis and implementation details of a frequency adaptive synchronization unit (FASU) capable of extracting the positive, negative, and zero sequence components of a three-phase signal as well as real-time tracking of the amplitude, phase, and frequency of the positive sequence component. The FASU consists of three subsystems: First, a sequence component extractor block based on a fast retrieval technique, second, a zero-crossing peak detection system with dynamic dc compensation and, third, a frequency adaptive multi-input multioutput low-pass finite-impulse response filter. The frequency adaptive filter is able to provide filtering of the positive sequence component over a wide frequency range (40-2000 Hz), in the presence of significant input signal distortion (total harmonic distortion as high as 100%). The system achieves a worst case transient response time of one and a half-cycle of the input period, in the event of input transients such as balanced/unbalanced amplitude sags and swells, balanced/unbalanced phase steps, and positive/negative frequency ramps (up to 700 Hz/s). The proposed system is suitable for use in islanded microgrids, in the aerospace industry, and as a phasor measurement unit. The system is implemented as a proof of concept on a field programmable gate array hardware platform. Auteurs: Essam S. Elsahwi;Adrian Zsombor Amanci;Francis P. Dawson; Apparue dans: IEEE Transactions on Power Delivery Date publication: 08.-2017, volume: 32, issue:4, pages: 2070 - 2080 Editeur: IEEE Document complet vers site de l'éditeur
» A Distance-Based Two-Stage Ecological Driving System Using an Estimation of Distribution Algorithm and Model Predictive Control
 Résumé:This paper proposes a distance-based two-stage ecological (eco-) driving scheme by using estimation of distribution algorithms (EDA) and model-based prediction of traffic conditions. Before departure, the optimal speed profile for an entire route is generated by an EDA in combination with speedup approaches for a faster computing time, which can optimize the complex cost function of ecodriving without simplification within a reasonably short computing time. This optimization is performed in a distance domain for localizing changes in the optimal speed profile due to traffic conditions while driving. After departure, by taking the optimal speed profile and actual traffic conditions into consideration, the speed profile for a short term—to only the next location—is adapted. In order to reliably react to actual traffic conditions, additional points are interpolated into the long-term distance step and fine control of speeds at the additional points is established, which is based on a predictive model for estimating the spacing to the preceding vehicle. The proposed ecodriving system is evaluated in two types of route conditions, and its results are compared with the optimization result by the quadratic programming method. This comparison shows that an EDA can generate a speed profile with better optimization results in terms of fuel efficiency and driving time within a shorter computing time. Auteurs: Hansang Lim;Chunting Chris Mi;Wencong Su; Apparue dans: IEEE Transactions on Vehicular Technology Date publication: 08.-2017, volume: 66, issue:8, pages: 6663 - 6675 Editeur: IEEE Document complet vers site de l'éditeur
» A Distributed Parallel Cooperative Coevolutionary Multiobjective Evolutionary Algorithm for Large-Scale Optimization
 Résumé:A considerable amount of research has been devoted to multiobjective optimization problems. However, few studies have aimed at multiobjective large-scale optimization problems (MOLSOPs). To address MOLSOPs, which may involve big data, this paper proposes a message passing interface MPI -based distributed parallel cooperative coevolutionary multiobjective evolutionary algorithm (DPCCMOEA). DPCCMOEA tackles MOLSOPs based on decomposition. First, based on a modified variable analysis method, we separate decision variables into several groups, each of which is optimized by a subpopulation (species). Then, the individuals in each subpopulation are further separated to several sets. DPCCMOEA is implemented with MPI distributed parallelism and a two-layer parallel structure is constructed. We examine the proposed algorithm using the multiobjective test suites Deb-Thiele-Laumanns-Zitzler and Walking-Fish-Group. In comparison with cooperative coevolutionary generalized differential evolution 3 and multiobjective evolutionary algorithm based on decision variable analyses, which are state-of-the-art cooperative coevolutionary multiobjective evolutionary algorithms, experimental results show that the novel algorithm has better performance in both optimization results and time consumption. Auteurs: Bin Cao;Jianwei Zhao;Zhihan Lv;Xin Liu; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 08.-2017, volume: 13, issue:4, pages: 2030 - 2038 Editeur: IEEE Document complet vers site de l'éditeur
» A Distributed Version of the Hungarian Method for Multirobot Assignment
 Résumé:In this paper, we propose a distributed version of the Hungarian method to solve the well-known assignment problem. In the context of multirobot applications, all robots cooperatively compute a common assignment that optimizes a given global criterion (e.g., the total distance traveled) within a finite set of local computations and communications over a peer-to-peer network. As a motivating application, we consider a class of multirobot routing problems with “spatiotemporal” constraints, i.e., spatial targets that require servicing at particular time instants. As a means of demonstrating the theory developed in this paper, the robots cooperatively find online suboptimal routes by applying an iterative version of the proposed algorithm in a distributed and dynamic setting. As a concrete experimental test bed, we provide an interactive “multirobot orchestral” framework, in which a team of robots cooperatively plays a piece of music on a so-called orchestral floor. Auteurs: Smriti Chopra;Giuseppe Notarstefano;Matthew Rice;Magnus Egerstedt; Apparue dans: IEEE Transactions on Robotics Date publication: 08.-2017, volume: 33, issue:4, pages: 932 - 947 Editeur: IEEE Document complet vers site de l'éditeur
» A Dual-Channel MEMS Amplitude Demodulator for On-Line Detection in Radio Relay Station
 Résumé:A dual-channel amplitude demodulator based on a micro-electromechanical systems (MEMS) approach for radio relay station on-line detection is proposed in this letter. This MEMS demodulator adopts a clamped–clamped beam to couple part of the signal from the main line to dual channels for on-line amplitude demodulation. The MEMS-based demodulation applies the square law of the thermal converter. The fabrication of the device is compatible with GaAs monolithic microwave integrated circuit process. Experiments show that the on-line MEMS demodulator has a return loss that is better than 20 dB, and an insertion loss of less than 0.5 dB up to 10 GHz. This design can realize direct demodulation of an amplitude modulation signal with a carrier frequency of 0.01–10 GHz. Auteurs: Hao Yan;Xiaoping Liao;Chenglin Li; Apparue dans: IEEE Electron Device Letters Date publication: 08.-2017, volume: 38, issue:8, pages: 1121 - 1124 Editeur: IEEE Document complet vers site de l'éditeur
» A Dual-Polarized Dual-Band Antenna With Omni-Directional Radiation Patterns
 Résumé:A new dual-polarized dual-band (DPDB) omni-directional antenna is presented in this communication. The proposed antenna consists of a circular patch with eight open slots, eight shorted metal pins, and a central feed coaxial probe. By utilizing TM01 mode, eight shorted metal pins, and open slots can radiate $\theta$ - and $\varphi$ -components, respectively. Omni-directional circular polarization can be generated over the lower band. When the basic TM02 mode is excited, omni-directional linear polarization can be generated over the higher band. Omni-directional circularly polarized fields and omni-directional linearly polarized fields can be achieved at both resonant frequencies. The circular patch antenna is printed on a substrate with a radius of 48 mm ( $0.24~\lambda _{\mathrm {\mathbf {0}}}$ , where $\lambda _{\mathrm {\mathbf {0}}}$ is the wavelength in free space). The antenna has a low profile of 4 mm ( $0.02~\lambda _{\mathrm {\mathbf {0}}}$ ). The antenna is fabricated and measured; the measured results show that the impedance bandwidths for VSWR <2 are 18 MHz (1566—1584 MHz) and 32 MHz (2440—2472 MHz). The axial ratio in the xoy plane is less than 3 dB over the lower band. These measured results are congruent with the simulated data. The antenna can be a good candidate for both GPS and WLAN applications. Besides, the S-parameters, radiation patterns, and some key structures are studied. Auteurs: Yi Liu;Xi Li;Lin Yang;Ying Liu; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 08.-2017, volume: 65, issue:8, pages: 4259 - 4262 Editeur: IEEE Document complet vers site de l'éditeur
» A Dynamic Topic Model and Matrix Factorization-Based Travel Recommendation Method Exploiting Ubiquitous Data
 Résumé:The vast volumes of community-contributed geotagged photos (CCGPs) available on the Web can be utilized to make travel location recommendations. The sparsity of user location interactions makes it difficult to learn travel preferences, because a user usually visits only a limited number of travel locations. Static topic models can be used to solve the sparsity problem by considering user travel topics. However, all travel histories of a user are regarded as one document drawn from a set of static topics, ignoring the evolving of topics and travel preferences. In this paper, we propose a dynamic topic model (DTM) and matrix factorization (MF)-based travel recommendation method. A DTM is used to obtain the temporally fine-grained topic distributions (i.e., implicit topic information) of users and locations. In addition, a large amount of explicit information is extracted from the metadata and visual contents of CCGPs, check-ins, and point of interest categories datasets. The information is used to obtain user–user and location–location similarity information, which is imposed as two regularization terms to constraint MF. The proposed method is evaluated on a publicly available Flickr dataset. Experimental results demonstrate that the proposed method can generate significantly superior recommendations compared to other state-of-the-art travel location recommendation studies. Auteurs: Zhenxing Xu;Ling Chen;Yimeng Dai;Gencai Chen; Apparue dans: IEEE Transactions on Multimedia Date publication: 08.-2017, volume: 19, issue:8, pages: 1933 - 1945 Editeur: IEEE Document complet vers site de l'éditeur
» A Dynamic Wireless Power Transfer System Applicable to a Stationary System
 Résumé:Solving a short mileage and a long charging time is indispensable in putting electrical vehicles (EVs) on the full-scale market. A dynamic wireless power transfer (WPT) system is one of the effective solutions, because it can feed electric power to moving EVs. This paper proposes a dynamic WPT system consisting of several stationary ground-side (primary) coils and a moving vehicle-side (secondary) coil. This system is characterized by the use of the common vehicle-side coil to both dynamic and stationary WPT situations. Theoretical analysis concludes that the dynamic WPT system resulting from a stationary WPT system is the same in equivalent circuit as the stationary system. The dynamic WPT system employs solenoid coils that are superior to circular coils in terms of misalignment and flux-distribution performance. A downscaled dynamic WPT system rated at 3 kW is designed, constructed, and tested to verify the principles of operation, and the capability of continuous power transfer. Auteurs: Toshiyuki Fujita;Tomio Yasuda;Hirofumi Akagi; Apparue dans: IEEE Transactions on Industry Applications Date publication: 08.-2017, volume: 53, issue:4, pages: 3748 - 3757 Editeur: IEEE Document complet vers site de l'éditeur
» A Family of Zero-Voltage-Switching Magnetic Coupling Nonisolated Bidirectional DC–DC Converters
 Résumé:This paper proposes a family of magnetic coupling nonisolated bidirectional dc–dc converters, which can achieve soft-switching operation in both power flow directions with a simple auxiliary circuit. Compared with conventional zero-voltage-transition converters, the additional resonant inductor is eliminated and magnetic core number is reduced. Therefore, both high efficiency and low cost are achieved. First, a general zero-voltage-switching (ZVS) magnetic coupling structure is proposed for a bidirectional buck/boost converter, based on which 13 different ZVS topologies with different connections of auxiliary circuit are derived. It is very beneficial in practical industrial applications because engineers can choose an optimal one according to converter performance characteristics, and the topology derivation methodology can be easily extended to other bidirectional dc–dc converters. Second, based on the general structure, operation principle and performance characteristics of all proposed topologies are simultaneously obtained, which can facilitate topology comparison and selection processes. Finally, in order to verify the effectiveness of theoretical analysis, design considerations and experiment results of a 500-W prototype circuit are demonstrated. Auteurs: Guipeng Chen;Yan Deng;Luan Chen;Yihua Hu;Lin Jiang;Xiangning He;Yousheng Wang; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 08.-2017, volume: 64, issue:8, pages: 6223 - 6233 Editeur: IEEE Document complet vers site de l'éditeur
» A Fast Density and Grid Based Clustering Method for Data With Arbitrary Shapes and Noise
 Résumé:This paper presents a density- and grid- based (DGB) clustering method for categorizing data with arbitrary shapes and noise. As most of the conventional clustering approaches work only with round-shaped clusters, other methods are needed to be explored to proceed classification of clusters with arbitrary shapes. Clustering approach by fast search and find of density peaks and density-based spatial clustering of applications with noise, and so many other methods are reported to be capable of completing this task but are limited by their computation time of mutual distances between points or patterns. Without the calculation of mutual distances, this paper presents an alternative method to fulfill clustering of data with any shape and noise even faster and with more efficiency. It was successfully verified in clustering industrial data (e.g., DNA microarray data) and several benchmark datasets with different kinds of noise. It turned out that the proposed DGB clustering method is more efficient and faster in clustering datasets with any shape than the conventional methods. Auteurs: Bo Wu;Bogdan M. Wilamowski; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 08.-2017, volume: 13, issue:4, pages: 1620 - 1628 Editeur: IEEE Document complet vers site de l'éditeur
» A Fast Edge Extraction Method for Mobile Lidar Point Clouds
 Résumé:Edges in mobile light detection and ranging (lidar) point clouds are important for many applications but usually overlooked. In this letter, we propose a fast edge extraction method for mobile lidar. First, an edge index based on geometric center is introduced and then gradients in unorganized 3-D point clouds are defined. By analyzing the ratio between eigenvalues, edge candidates can be detected. Finally, an edge linking algorithm named graph snapping is proposed. The method is tested extensively and the experimental results demonstrate that the proposed method is able to quickly extract most of 3-D edges with higher accuracy than the existing methods. Auteurs: Shaobo Xia;Ruisheng Wang; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 08.-2017, volume: 14, issue:8, pages: 1288 - 1292 Editeur: IEEE Document complet vers site de l'éditeur
» A Fiber-Optic Mechanoreceptor in a Finger-Shaped End Effector for Human-Like Tactile Sensing
 Résumé:An artificial mechanoreceptor based on a hetero-core fiber-optic sensor has been developed using a reflective-type sensor element for realizing human-like sensations for multiple tactile information on artificial structures. The proposed mechanoreceptor is embedded in a finger-shaped end effector as a pseudoartificial finger in order to evaluate how the end effector responds to a variety of tactile information. The end effector can detect contact forces in the range of 0.02–4 N with a maximum force sensitivity of 3.23 dB/N and is sensitive in a local area contact within 2 mm, which is comparable with the spatial resolution of human fingertips. The end effector can also detect vibrations at frequencies up to 1 kHz. The developed end effector is also tested in assessing the hardness of a soft resin material in the range of 5°–80° on the Shore A hardness scale, and in discriminating surface conditions when scanned across a surface. Auteurs: Hiroshi Yamazaki;Michiko Nishiyama;Kazuhiro Watanabe; Apparue dans: IEEE Sensors Journal Date publication: 08.-2017, volume: 17, issue:16, pages: 5123 - 5129 Editeur: IEEE Document complet vers site de l'éditeur
» A Fitting Model for Feature Selection With Fuzzy Rough Sets
 Résumé:A fuzzy rough set is an important rough set model used for feature selection. It uses the fuzzy rough dependency as a criterion for feature selection. However, this model can merely maintain a maximal dependency function. It does not fit a given dataset well and cannot ideally describe the differences in sample classification. Therefore, in this study, we introduce a new model for handling this problem. First, we define the fuzzy decision of a sample using the concept of fuzzy neighborhood. Then, a parameterized fuzzy relation is introduced to characterize the fuzzy information granules, using which the fuzzy lower and upper approximations of a decision are reconstructed and a new fuzzy rough set model is introduced. This can guarantee that the membership degree of a sample to its own category reaches the maximal value. Furthermore, this approach can fit a given dataset and effectively prevents samples from being misclassified. Finally, we define the significance measure of a candidate attribute and design a greedy forward algorithm for feature selection. Twelve datasets selected from public data sources are used to compare the proposed algorithm with certain existing algorithms, and the experimental results show that the proposed reduction algorithm is more effective than classical fuzzy rough sets, especially for those datasets for which different categories exhibit a large degree of overlap. Auteurs: Changzhong Wang;Yali Qi;Mingwen Shao;Qinghua Hu;Degang Chen;Yuhua Qian;Yaojin Lin; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 08.-2017, volume: 25, issue:4, pages: 741 - 753 Editeur: IEEE Document complet vers site de l'éditeur
» A Fixed-Lag Kalman Smoother to Filter Power Line Interference in Electrocardiogram Recordings
 Résumé:Objective: Filtering power line interference (PLI) from electrocardiogram (ECG) recordings can lead to significant distortions of the ECG and mask clinically relevant features in ECG waveform morphology. The objective of this study is to filter PLI from ECG recordings with minimal distortion of the ECG waveform. Methods : In this paper, we propose a fixed-lag Kalman smoother with adaptive noise estimation. The performance of this Kalman smoother in filtering PLI is compared to that of a fixed-bandwidth notch filter and several adaptive PLI filters that have been proposed in the literature. To evaluate the performance, we corrupted clean neonatal ECG recordings with various simulated PLI. Furthermore, examples are shown of filtering real PLI from an adult and a fetal ECG recording. Results: The fixed-lag Kalman smoother outperforms other PLI filters in terms of step response settling time (improvements that range from 0.1 to 1 s) and signal-to-noise ratio (improvements that range from 17 to 23 dB). Our fixed-lag Kalman smoother can be used for semi real-time applications with a limited delay of 0.4 s. Conclusion and Significance: The fixed-lag Kalman smoother presented in this study outperforms other methods for filtering PLI and leads to minimal distortion of the ECG waveform. Auteurs: G. J. J. Warmerdam;R. Vullings;L. Schmitt;J. O. E. H. Van Laar;J. W. M. Bergmans; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 08.-2017, volume: 64, issue:8, pages: 1852 - 1861 Editeur: IEEE Document complet vers site de l'éditeur
» A Formal Methodology for Accomplishing IEC 61850 Real-Time Communication Requirements
 Résumé:Reliability is extremely important for control systems of energy distribution and generation. The IEC 61850 standard specifies an open architecture and communication protocols for such applications. The standard defines an open control architecture for networked control systems composed by intelligent electronic devices, stating some requirements that must be accomplished when developing reliable controllers for such systems. In this paper, we present a systematic and formal methodology to be adopted to achieve the correct implementation of the communication requirements of this standard. The methodology consists in five steps: modeling of real-time communication requirements defined by the standard; simulation of the obtained model; formal verification of the model, improved in the previous step; translation of the global model (simulated and verified) into the input language of the real controller; and finally, application of conformance testing technique to the computational routine implemented in the real controller. Presented research deals with the proposition of a strategy to synthesize and validate models of systems developed under IEC61850 real-time requirements (GOOSE and SMV) through simple operational conditions cases that, once validated, can be used in performance and conformance testing of more complex systems. The proposed methodology allows designers to synthesize reliable systems under IEC61850 real-time communication requirements. Auteurs: Guilherme Kunz;José Machado;Eduardo Perondi;Valeriy Vyatkin; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 08.-2017, volume: 64, issue:8, pages: 6582 - 6590 Editeur: IEEE Document complet vers site de l'éditeur
» A Frequency-Sweeping Framework for Stability Analysis of Time-Delay Systems
 Résumé:For time-delay systems, the asymptotic behavior analysis of the critical imaginary roots w.r.t. the infinitely many critical delays is an open problem. In order to find a general solution, we will exploit the link between the asymptotic behavior of critical imaginary roots and the asymptotic behavior of frequency-sweeping curves, from a new analytic curve perspective. As a consequence, we will establish a frequency-sweeping framework with three main results: (1) A finer (regularity-singularity) classification for time-delay systems will be obtained. (2) The general invariance property will be proved and hence the asymptotic behavior of the critical imaginary roots w.r.t. the infinitely many critical delays can be adequately studied. (3) The complete stability problem can be fully solved. Moreover, the frequency-sweeping framework is extended to cover a broader class of time-delay systems. Finally, the geometric insights of frequency-sweeping curves are investigated. Consequently, some deeper properties on the asymptotic behavior of time-delay systems and the link to frequency-sweeping curves are found. Auteurs: Xu-Guang Li;Silviu-Iulian Niculescu;Arben Çela;Lu Zhang;Xu Li; Apparue dans: IEEE Transactions on Automatic Control Date publication: 08.-2017, volume: 62, issue:8, pages: 3701 - 3716 Editeur: IEEE Document complet vers site de l'éditeur
» A Fully Passive Compressive Sensing SAR ADC for Low-Power Wireless Sensors
 Résumé:The compressive sensing (CS) theory states that the sparsity of a signal can be exploited to reduce the analog-to-digital converter (ADC) conversion rate and save power. However, most previous CS frameworks require dedicated analog CS encoders built by power-hungry active amplifiers, which limit the overall power saving. Differently, this paper proposes a fully passive switched-capacitor-based CS framework that directly embeds CS into a successive-approximation-register (SAR) ADC. The proposed CS-SAR ADC can operate in two modes: the Nyquist mode and the CS mode. In the CS mode, the CS-SAR ADC quantizes the input once every four-time sampling, reducing the conversion rate and the circuit power by four times compared to the Nyquist mode. A prototype chip is fabricated in a 0.13- $\mu \text{m}$ CMOS process. At 0.8 V and 1 MS/s, the chip consumes 19.2 $\mu \text{W}$ in the Nyquist mode and $5\mu \text{W}$ in the CS mode. Discrete-tone signals are converted and reconstructed with a peak signal-to-noise plus distortion ratio (SNDR) of 61 dB and maximum bandwidth occupancy of 8.2%. Speech signals are also used to demonstrate the capability of the chip to compressively sense real-world signals. Compared to prior CS works, it improves the post-reconstruction SNDR by 18 dB and the energy efficiency by 13 times. Auteurs: Wenjuan Guo;Youngchun Kim;Ahmed H. Tewfik;Nan Sun; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 08.-2017, volume: 52, issue:8, pages: 2154 - 2167 Editeur: IEEE Document complet vers site de l'éditeur
» A Fuzzy Approach Based on Heterogeneous Metrics for Scaling Out Public Clouds
 Résumé:Thanks to resource elasticity, cloud systems allow to build high performance applications by dynamically adapting resources to workload dynamics. In this paper, we present a novel approach for horizontally scaling cloud resources. The approach is based on an optimized feedback control scheme that leverages fuzzy logic to self-adjust its parameters in order to cope with unpredictable and highly time-varying public-cloud operating conditions. The proposed approach takes as input heterogeneous monitoring metrics related to distinct aspects of interest (i.e., CPU and network load) merged through a fitness function. Therefore, it is able to accomplish the application needs from different viewpoints. The extensive experimental evaluation performed in the Amazon EC2 environment showed how the proposed approach is robust against a number of realistic workloads—also when VM failures happen— and that it is flexible, as being suitable for applications with different needs. Finally, it also achieves better performance when compared to previously proposed solutions. Auteurs: Valerio Persico;Domenico Grimaldi;Antonio Pescapè;Alessandro Salvi;Stefania Santini; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 08.-2017, volume: 28, issue:8, pages: 2117 - 2130 Editeur: IEEE Document complet vers site de l'éditeur
» A General and Transformable Model Platform for Emerging Multi-Gate MOSFETs
 Résumé:The complete general solution of nonlinear 1-D undoped Poisson’s equation, in both Cartesian and cylindrical coordinates, is derived by employing a special variable transformation method. A general model platform for various types of emerging multi-gate MOSFETs is further constructed and verified with TCAD simulations. It is shown that this model platform is suitable for analyzing a series of emerging devices, such as double-surrounding-gate, inner-surrounding-gate, and outer-surrounding-gate nanoshell MOSFETs, all of which require different boundary conditions from the conventional gate-all-around nanowire device. Auteurs: Chuyang Hong;Jun Zhou;Jiasheng Huang;Rui Wang;Wenlong Bai;James B. Kuo;Yijian Chen; Apparue dans: IEEE Electron Device Letters Date publication: 08.-2017, volume: 38, issue:8, pages: 1015 - 1018 Editeur: IEEE Document complet vers site de l'éditeur
» A Gridless Approach to the Satisfiability of Self-Aligned Triple Patterning
 Résumé:Self-aligned triple patterning (SATP) lithography is one of the most promising technologies for next-generation semiconductor manufacturing process. Self-aligned patterning attracts much interest because of its significant advantage over the litho-etch-litho-etch patterning in reducing the overlay problem in lithography. However, pattern decomposition in SATP is challenging due to its counterintuitive mask synthesis. It remains relatively unstudied and its practical solutions remain to be proposed. This paper proposes an effective algorithm for SATP layout decomposition without grid-based quantization and thus substantially reduces the number of variables and constraints in solution search. Boolean satisfiability (SAT) and integer linear programming (ILP) are exploited for efficient computation. In addition to deriving high-quality layout decomposition solutions with overlay minimization, our method also allows nondecomposable spot identification to facilitate layout rectification. Experimental results demonstrate the superiority of our method compared to prior work and show the relative advantages of SAT and ILP formulations. Auteurs: Hsiao-Lei Chien;Mei-Yen Chiu;Jie-Hong R. Jiang; Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Date publication: 08.-2017, volume: 36, issue:8, pages: 1251 - 1264 Editeur: IEEE Document complet vers site de l'éditeur
» A Hardware-Efficient Scalable Spike Sorting Neural Signal Processor Module for Implantable High-Channel-Count Brain Machine Interfaces
 Résumé:Next-generation brain machine interfaces demand a high-channel-count neural recording system to wirelessly monitor activities of thousands of neurons. A hardware efficient neural signal processor (NSP) is greatly desirable to ease the data bandwidth bottleneck for a fully implantable wireless neural recording system. This paper demonstrates a complete multichannel spike sorting NSP module that incorporates all of the necessary spike detector, feature extractor, and spike classifier blocks. To meet high-channel-count and implantability demands, each block was designed to be highly hardware efficient and scalable while sharing resources efficiently among multiple channels. To process multiple channels in parallel, scalability analysis was performed, and the utilization of each block was optimized according to its input data statistics and the power, area and/or speed of each block. Based on this analysis, a prototype 32-channel spike sorting NSP scalable module was designed and tested on an FPGA using synthesized datasets over a wide range of signal to noise ratios. The design was mapped to 130 nm CMOS to achieve 0.75 μW power and 0.023 mm2 area consumptions per channel based on post synthesis simulation results, which permits scalability of digital processing to 690 channels on a 4×4 mm2 electrode array. Auteurs: Yuning Yang;Sam Boling;Andrew J. Mason; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 08.-2017, volume: 11, issue:4, pages: 743 - 754 Editeur: IEEE Document complet vers site de l'éditeur
» A Hierarchical Data Transmission Framework for Industrial Wireless Sensor and Actuator Networks
 Résumé:A smart factory generates vast amounts of data that require transmission via large-scale wireless networks. Thus, the reliability and real-time performance of large-scale wireless networks are essential for industrial production. A distributed data transmission scheme is suitable for large-scale networks, but is incapable of optimizing performance. By contrast, a centralized scheme relies on knowledge of global information and is hindered by scalability issues. To overcome these limitations, a hybrid scheme is needed. We propose a hierarchical data transmission framework that integrates the advantages of these schemes and makes a tradeoff among real-time performance, reliability, and scalability. The top level performs coarse-grained management to improve scalability and reliability by coordinating communication resources among subnetworks. The bottom level performs fine-grained management in each subnetwork, for which we propose an intrasubnetwork centralized scheduling algorithm to schedule periodic and aperiodic flows. We conduct both extensive simulations and realistic testbed experiments. The results indicate that our method has better schedulability and reduces packet loss by up to $22\%$ relative to existing methods. Auteurs: Xi Jin;Fanxin Kong;Linghe Kong;Huihui Wang;Changqing Xia;Peng Zeng;Qingxu Deng; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 08.-2017, volume: 13, issue:4, pages: 2019 - 2029 Editeur: IEEE Document complet vers site de l'éditeur
» A Hierarchical Fused Fuzzy Deep Neural Network for Data Classification
 Résumé:Deep learning (DL) is an emerging and powerful paradigm that allows large-scale task-driven feature learning from big data. However, typical DL is a fully deterministic model that sheds no light on data uncertainty reductions. In this paper, we show how to introduce the concepts of fuzzy learning into DL to overcome the shortcomings of fixed representation. The bulk of the proposed fuzzy system is a hierarchical deep neural network that derives information from both fuzzy and neural representations. Then, the knowledge learnt from these two respective views are fused altogether forming the final data representation to be classified. The effectiveness of the model is verified on three practical tasks of image categorization, high-frequency financial data prediction and brain MRI segmentation that all contain high level of uncertainties in the raw data. The fuzzy dDL paradigm greatly outperforms other nonfuzzy and shallow learning approaches on these tasks. Auteurs: Yue Deng;Zhiquan Ren;Youyong Kong;Feng Bao;Qionghai Dai; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 08.-2017, volume: 25, issue:4, pages: 1006 - 1012 Editeur: IEEE Document complet vers site de l'éditeur
» A High-Efficiency 60-GHz CMOS Transmitter for Short-Range Wireless Communications
 Résumé:This letter presents a high-efficiency 60-GHz CMOS transmitter for short-range wireless communications. The transmitter comprises a voltage-controlled oscillator and a modulator and uses on–off keying (OOK) modulation for a compact and low-power design. A frequency-doubling modulation technique produces a compact and highly efficient modulator with high on–off isolation. Therefore, the transmitter consumes low power and exhibits a high data-rate capability. Implemented in 65-nm CMOS technology, the transmitter consumes 12.2 mW and occupies a core chip area of 0.04 mm2. The transmitter achieves 11.5-Gb/s wireless OOK data transmission over a distance of 2 cm at a bit error rate of less than $10^{-12}$ for $2^{7}- 1$ PRBS. As a result, the proposed transmitter exhibits an energy efficiency of 1.1 pJ/b. Auteurs: Chul Woo Byeon;Chul Soon Park; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 08.-2017, volume: 27, issue:8, pages: 751 - 753 Editeur: IEEE Document complet vers site de l'éditeur
» A High-Efficiency Step-Up Current-Fed Push–Pull Quasi-Resonant Converter With Fewer Components for Fuel Cell Application
 Résumé:In this paper, a new high-efficiency step-up current-fed push–pull quasi-resonant converter is proposed, which is suitable for low-voltage fuel cell power conditioning system. The proposed converter conserves inherent advantages of low-input-current stress and high voltage conversion ratio of the conventional current-fed push–pull converter. All of power devices can achieve soft switching at light load improving the overall efficiency. Moreover, similar features have been obtained with fewer components in comparison with the active-clamped current-fed push–pull converter [37] and current-fed push–pull resonant converter [40], that enabling to reduce the cost and improve system reliability. In addition, the voltage-doubler rectifier is adopted to eliminate the reverse-recovery problem of secondary diodes and provides much higher voltage conversion ratio resulting in small turn ratio of the high-frequency transformer. Detailed operation, analysis, design, comparative study, experimental results, and loss breakdown for the proposed converter are presented in the paper. A 510-W prototype verifies the theoretical analysis and the effectiveness of the proposed concept. Auteurs: Qunfang Wu;Qin Wang;Jialin Xu;Hongxu Li;Lan Xiao; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 08.-2017, volume: 64, issue:8, pages: 6639 - 6648 Editeur: IEEE Document complet vers site de l'éditeur
» A Highly Accurate Calibration Method for Terrestrial Laser Doppler Velocimeter
 Résumé:In order to obtain the accurate velocity of a vehicle, calibration of a laser Doppler velocimeter (LDV) is particularly important after installation of the inertial navigation system (INS) and LDV. The calibration accuracy determines the navigational accuracy of the INS/LDV integrated navigation system. In this paper, a highly accurate calibration method based on the error equations of the INS/LDV integrated system is presented. The basic principles of analytic calibration and filtering calibration methods are discussed in detail. The test results show that the scale factor and the installation error of the LDV can be automatically calibrated by our novel calibration method with sufficient accuracy. For a high-precision INS and a 2-D LDV integrated navigation system, after calibration, the position error of dead reckoning (DR) decreased from 1180 m in 2 h to 8 m in 2 h. For a medium precision INS and a 1-D LDV integrated navigation system, after calibration, the position error of DR decreased from 1300 m in 1 h to 25 m in 1 h. The excellent parameter stability of the LDV is also illustrated. Auteurs: Chunfeng Gao;Qi Wang;Guo Wei;Xingwu Long; Apparue dans: IEEE Transactions on Instrumentation and Measurement Date publication: 08.-2017, volume: 66, issue:8, pages: 1994 - 2003 Editeur: IEEE Document complet vers site de l'éditeur
» A Highly Linear Temperature Sensor Using GaN-on-SiC Heterojunction Diode for High Power Applications
 Résumé:Silicon carbide (SiC) power devices have been commercialized up to 1.7 kV with operating temperatures up to 573 K. The temperature limitations of SiC devices are generally derived from limitations in packaging and a lack of information on safe operating temperature regimes. Therefore, it is highly desirable to develop reliable temperature sensing techniques that can better take advantage of the SiC devices in high power applications. In this letter, ten gallium nitride (GaN)-on-SiC heterojunction diodes, aiming at high-power and high-temperature sensing applications, were fabricated using concentric ring geometry. These sensors can be monolithically integrated into GaN-on-SiC RF/Microwave power devices with fast-switching frequency and high-power density. The temperature dependent characteristics of the forward voltage drop at fixed current ( $V_{D}-{T}$ ) of these heterojunction devices and their sensitivities (mV/K) are comprehensively characterized in a temperature range from 300 to 650 K. These devices exhibit a high degree of linearity in their $V_{D}-{T}$ characteristics, which indicates the potential to be used as temperature sensors up to 650 K. Auteurs: S. Madhusoodhanan;S. Sandoval;Y. Zhao;M. E. Ware;Z. Chen; Apparue dans: IEEE Electron Device Letters Date publication: 08.-2017, volume: 38, issue:8, pages: 1105 - 1108 Editeur: IEEE Document complet vers site de l'éditeur
» A Hurricane Wind Speed Retrieval Model for C-Band RADARSAT-2 Cross-Polarization ScanSAR Images
 Résumé:A hybrid backscattering model is built to provide a consistent description for C-band VH- and VV-polarized normalized radar cross sections (NRCSs). Ocean surface co- and cross-polarized NRCS are both treated as a sum of Bragg and non-Bragg scattering components. To better understand the synthetic aperture radar (SAR) observed NRCS signals under high-wind conditions, five C-band RADARSAT-2 dual-polarization SAR hurricane images and the collocated wind vectors measured by the airborne stepped-frequency microwave radiometer (SFMR) are collected. Based on the match-up data, we add a non-Bragg term in the composite Bragg theory to explain the discrepancy between the measurements in the cross-polarization channel and the existing theory results. The non-Bragg scattering to Bragg scattering ratio ( $B_{r}$ ) is found to be a constant. We build the hybrid backscattering model with $B_{r}$ and establish a relationship between the cross-polarization NRCS and the radar incidence angle under different wind conditions. The NRCS dependence on incidence angle is simulated by the hybrid backscattering model. Finally, a C-band Cross-Polarization Coupled-Parameters Ocean (C-3PO) model is developed to retrieve hurricane winds using VH-polarized ScanSAR by including the radar incidence angle. The collocated SAR and SFMR data sets are separated into two parts: data set-A, for hybrid backscattering model derivation and C-3PO model coefficients tuning, and data set-B, for hurricane wind validation. C-3PO model validation results show that the model is suitable for ocean surface wind mapping from RADARSAT-2 cross-polarization ScanSAR images. The retrieval has a root-mean-square error less than 3 m/s for wind speed up to 40 m/s. Auteurs: Guosheng Zhang;Xiaofeng Li;William Perrie;Paul A. Hwang;Biao Zhang;Xiaofeng Yang; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 08.-2017, volume: 55, issue:8, pages: 4766 - 4774 Editeur: IEEE Document complet vers site de l'éditeur
» A Hybrid Diesel-Wind­PV-Based Energy Generation System With Brushless Generators
 Résumé:This paper presents an experimental implementation of a standalone microgrid topology based on a single voltage source converter (VSC) and brushless generators. The microgrid system is energised with different renewable energy sources namely wind and solar PV array. However, a diesel generator (DG) set and a battery energy storage system (BESS) are also used to maintain the reliability of the system. The proposed topology has the advantage of reduced switching devices and simple control. The implemented topology has DG set as an ac source. The wind generator and the solar PV array are dc sources which are connected to the dc link of the VSC. The BESS is also used at the dc link to facilitate the instantaneous power balance under dynamic conditions. Along with the system integration, the VSC also has the capability to mitigate the power quality problems such as harmonic currents, load balancing, and voltage regulation. A wide variety of test results are presented to demonstrate all the features of the proposed system. Auteurs: Krishan Kant;Chinmay Jain;Bhim Singh; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 08.-2017, volume: 13, issue:4, pages: 1714 - 1722 Editeur: IEEE Document complet vers site de l'éditeur
» A Hybrid Indirect–Direct Coupling Method for Strongly Coupled Nonlinear Magnetic Problems
 Résumé:Numerical simulations of nonlinear magnetic problems incorporating interactions of electromagnetics with material properties, thermal issues, and other physical fields, have recently attracted great interest among researchers. In this paper, the coupling strength of these interaction processes is defined. Based on this quantitative definition, we demonstrate that for strongly coupled magnetic problems a conventional indirect coupling scheme is likely to diverge. To overcome this difficulty, a hybrid indirect–direct coupling method is developed. The proposed method is a synergistic combination of a direct coupling scheme—for dealing with the nonlinearity of the coupled systems—and an indirect coupling scheme for preconditioning the heterogeneous systems. To improve the performance of the proposed method for strongly coupled systems, a parametric continuation strategy is introduced. The efficiency of the proposed method is validated through numerical tests. Auteurs: Jiawei Wang;Feng Chen;Xikui Ma; Apparue dans: IEEE Transactions on Magnetics Date publication: 08.-2017, volume: 53, issue:8, pages: 1 - 11 Editeur: IEEE Document complet vers site de l'éditeur
» A Hybrid Slot/Monopole Antenna With Directional Heating Patterns for Microwave Ablation
 Résumé:We present a new coax-fed interstitial antenna for generating directional heating patterns during microwave ablation. The antenna comprises a base-fed monopole wherein, a portion of the outer conductor is extended to create a reflector that directs the fields toward the opposing direction. To further direct the fields away from the reflector, we etched a semicylindrical slot in the outer conductor. The electric field produced by the slot constructively interferes with the field generated by the monopole in the desired radiation direction, while destructively interfering with the monopole’s field behind the reflector. This creates directional specific absorption rate and heating patterns. In addition, the reflector and slot suppress the unwanted currents along the antennas feeding cable. This eliminates the need for a balun and reduces the overall antenna diameter. The antenna is impedance matched using an internal $\pi$ - matching network. A prototype of this antenna, designed to operate at 7 GHz in egg white, was fabricated and used to perform ablation experiments at a power level of 20 W for 5 min. Experimental results agree well with simulations and confirm the capability of the antenna for generating directional heating patterns. Auteurs: Yahya Mohtashami;Susan C. Hagness;Nader Behdad; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 08.-2017, volume: 65, issue:8, pages: 3889 - 3896 Editeur: IEEE Document complet vers site de l'éditeur
» A Hybrid System for Measuring Solid and Liquid Contaminants in Steam Generators
 Résumé:This paper presents a hybrid device for real-time measurement and imaging of solid and liquid contaminants that may occur in steam generators. The device uses a dedicated near infrared device to determine the type of contaminants (i.e., water droplets and iron oxide particles) and a THz imaging system, which measures the amount of contaminants as well as its flow rate. The near infrared response (NIR) device can also determine the concentration of contaminants at sub-mg accuracy when its value is relatively low using spectrometry technique combined with principal component analysis (PCA). Three principal components (PC1, PC2, and PC3) were enough for this purpose. The PCA classification was performed using the least square support vector machine method. In case of relatively high concentration, the THz imaging system which uses block-based motion estimation algorithm can determine the velocity of individual contaminant particles to compute the global motion vector, the intensity and direction of which represents the overall flow rate and flow regime of the contaminants. The usage of image processing techniques together with an NIR spectrometry constitutes a new promising step in flow metering. This is demonstrated by the extensive experiments which have been conducted for different scenario where the NIR subsystem could determine the concentration of water droplets and solid contaminants with a maximum uncertainty of +/-1.45% and +/-1.16%, respectively. With the NIR subsystem, pixel-level accuracy of motion vector was achieved, whereas the concentration of solid contaminants showed consisted proportionality with the average pixel intensity. Auteurs: Mahmoud Meribout;E. Al Hosani;Imran M. Saied; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 08.-2017, volume: 64, issue:8, pages: 6549 - 6555 Editeur: IEEE Document complet vers site de l'éditeur
» A Joint Indoor WLAN Localization and Outlier Detection Scheme Using LASSO and Elastic-Net Optimization Techniques
 Résumé:In this paper, we introduce two indoor Wireless Local Area Network (WLAN) positioning methods using augmented sparse recovery algorithms. These schemes render a sparse user's position vector, and in parallel, minimize the distance between the online measurement and radio map. The overall localization scheme for both methods consists of three steps: 1) coarse localization, obtained from comparing the online measurements with clustered radio map. A novel graph-based method is proposed to cluster the offline fingerprints. In the online phase, a Region Of Interest (ROI) is selected within which we search for the user's location. 2) Access Point (AP) selection and 3) fine localization through the novel sparse recovery algorithms. Since the online measurements are subject to inordinate measurement readings, called outliers, the sparse recovery methods are modified in order to jointly estimate the outliers and user's position vector. The outlier detection procedure identifies the APs whose readings are either not available or erroneous. The proposed localization methods have been tested with Received Signal Strength (RSS) measurements in a typical office environment and the results show that they can localize the user with significantly high accuracy and resolution which is superior to the results from competing WLAN fingerprinting localization methods. Auteurs: Ali Khalajmehrabadi;Nikolaos Gatsis;Daniel J. Pack;David Akopian; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 08.-2017, volume: 16, issue:8, pages: 2079 - 2092 Editeur: IEEE Document complet vers site de l'éditeur
» A Kernel Direct Decomposition-Based Monitoring Approach for Nonlinear Quality-Related Fault Detection
 Résumé:This article considers the issue of quality-related process monitoring. A novel kernel direct decomposition (KDD) algorithm is proposed and a KDD-based nonlinear quality-related fault detection approach is designed. The proposed KDD algorithm first maps original process variables into feature space to deal with the nonlinearities among these variables. Feature matrix is then directly decomposed into two orthogonal parts according to its full correlation with output matrix without building any regression model. Compared with conventional nonlinear methods, the KDD-based approach has the following advantages: 1) it is simpler in design as it omits the steps of constructing a regression model like kernel partial least squares (KPLS); 2) its performance is more stable because it extracts the full correlation information of feature matrix unlike KPLS-based methods which only use the partial correlation information of several selected latent variables; and 3) it has a simpler diagnosis logic since it only uses two statistics to determine the type of fault while most existing methods need four. Simulations on a literature example and a simulated industrial process are used to demonstrate the advantages of the new method. Auteurs: Guang Wang;Jianfang Jiao;Shen Yin; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 08.-2017, volume: 13, issue:4, pages: 1565 - 1574 Editeur: IEEE Document complet vers site de l'éditeur
» A Light Illumination Enhancement Device for Photoacoustic Imaging: In Vivo Animal Study
 Résumé:Photoacoustic (PA) imaging detects acoustic signals generated by thermal expansion of a light-excited tissue or contrast agents. PA signal amplitude and image quality directly depend on the light fluence at the target depth. With conventional PA imaging systems, approximately 30% energy of incident light at the near-infrared region would be lost due to reflection on the skin surface. Such light loss directly leads to a reduction of PA signal and image quality. A new light delivery scheme that collects and redistributes reflected light energy was recently suggested, which is called the light catcher. In our previous study, proof of concept using a finite-element simulation model was shown and a laboratory-built prototype of the light catcher was applied on tissue-mimicking phantoms. In this paper, we present an elaborate prototype of a high-frequency PA probe with the light catcher fabricated using 3-D printing technology, which is conformal to a subcutaneous tumor in mice. The in vivo usefulness of the developed prototype was evaluated in a mouse tumor model. Equipped with the light catcher, PA signal amplitude from the clinical photosensitizer injected into the mouse tumor was enhanced by 33.7%, which is approximately equivalent to the percent light loss due to reflection on the skin. Auteurs: Jaesok Yu;Joel S. Schuman;Jung-Kun Lee;Sang-Goo Lee;Jin Ho Chang;Kang Kim; Apparue dans: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Date publication: 08.-2017, volume: 64, issue:8, pages: 1205 - 1211 Editeur: IEEE Document complet vers site de l'éditeur
» A Lightweight Contextual Arithmetic Coder for On-Board Remote Sensing Data Compression
 Résumé:The Consultative Committee for Space Data Systems (CCSDS) has issued several data compression standards devised to reduce the amount of data transmitted from satellites to ground stations. This paper introduces a contextual arithmetic encoder for on-board data compression. The proposed arithmetic encoder checks the causal adjacent neighbors, at most, to form the context and uses only bitwise operations to estimate the related probabilities. As a result, the encoder consumes few computational resources, making it suitable for on-board operation. Our coding approach is based on the prediction and mapping stages of CCSDS-123 lossless compression standard, an optional quantizer stage to yield lossless or near-lossless compression and our proposed arithmetic encoder. For both lossless and near-lossless compression, the achieved coding performance is superior to that of CCSDS-123, M-CALIC, and JPEG-LS. Taking into account only the entropy encoders, fixed-length codeword is slightly better than MQ and interleaved entropy coding. Auteurs: Joan Bartrina-Rapesta;Ian Blanes;Francesc Aulí-Llinàs;Joan Serra-Sagristà;Victor Sanchez;Michael W. Marcellin; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 08.-2017, volume: 55, issue:8, pages: 4825 - 4835 Editeur: IEEE Document complet vers site de l'éditeur
» A Linear Programming Approach for Minimizing a Linear Function Subject to Fuzzy Relational Inequalities With Addition–Min Composition
 Résumé:In this paper, we study an optimization problem of minimizing a linear function subject to fuzzy relational inequalities with the addition–min composition. This optimization setting has recently been proposed to model the network cogestion issue when a BitTorrent-like peer-to-peer file-sharing system is used for data transmission. In a 2014 paper, a pseudominimal index (PMI)-based approach was proposed to search for an optimal solution. It turns out that the PMI-based approach may require to solve several to many linear programming problems in order to get an optimal solution. In this paper, we point out that the feasible domain is indeed convex. And we only need to solve a single linear programming problem to generate an optimal solution for the original optimization problem. Furthermore, our approach could be extended to the case with a nonlinear continuous objective function. Auteurs: Sy-Ming Guu;Yan-Kuen Wu; Apparue dans: IEEE Transactions on Fuzzy Systems Date publication: 08.-2017, volume: 25, issue:4, pages: 985 - 992 Editeur: IEEE Document complet vers site de l'éditeur
» A Lithium-Ion Battery Current Estimation Technique Using an Unknown Input Observer
 Résumé:Current consumption measurements are useful in a wide variety of applications, including power monitoring and fault detection within a lithium-ion battery management system (BMS). This measurement is typically taken using either a shunt resistor or a Hall-effect current sensor. Although both methods have achieved accurate current measurements, shunt resistors have inherent power loss and require isolation circuitry, and Hall-effect sensors are generally expensive. This paper explores a novel alternative to sensing battery current by measuring terminal voltages and cell temperatures and using an unknown input observer to estimate the battery current. An accurate model of a LiFePO4 cell is created, validated, and then used to characterize a model of the proposed current estimation technique. Finally, the current estimation technique is implemented in hardware and tested in an online BMS environment. Results show that the current estimation technique is sufficiently accurate for a variety of applications, including fault detection and power profiling. Auteurs: Daniel C. Cambron;Aaron M. Cramer; Apparue dans: IEEE Transactions on Vehicular Technology Date publication: 08.-2017, volume: 66, issue:8, pages: 6707 - 6714 Editeur: IEEE Document complet vers site de l'éditeur
» A Load Balancing and Multi-Tenancy Oriented Data Center Virtualization Framework
 Résumé:Virtualization is an essential step before a bare-metal data center being ready for commercial usage, because it bridges the foreground interface for cloud tenants and the background resource management on underlying infrastructures. A concept at the heart of the foreground is multi-tenancy, which deals with logical isolation of shared virtual computing, storage, and network resources and provides adaptive capability for heterogeneous demands from various tenants. A crucial problem in the background is load balancing, which affects multiple issues including cost, flexibility and availability. In this work, we propose a virtualization framework that consider these two problems simultaneously. Our framework takes advantage of the flourishing application of distributed virtual switch (DVS), and leverages the blooming adoption of OpenFlow protocols. First, the framework accommodates heterogeneous network communication patterns by supporting arbitrary traffic matrices among virtual machines (VMs) in virtual private clouds (VPCs). The only constraint on the network flows is that the bandwidth of a server’s network interface. Second, our framework achieves load balancing using an elaborately designed link establishment algorithm. The algorithm takes the configurations of the bare-metal data center and the dynamic network environment as inputs, and adaptively applies a globally bounded oversubscription on every link. Our framework concentrates on the fat-tree architecture, which is widely used in today’s data centers. Auteurs: Jun Duan;Yuanyuan Yang; Apparue dans: IEEE Transactions on Parallel and Distributed Systems Date publication: 08.-2017, volume: 28, issue:8, pages: 2131 - 2144 Editeur: IEEE Document complet vers site de l'éditeur
» A Low Complexity Data Detection Algorithm for Uplink Multiuser Massive MIMO Systems
 Résumé:A major challenge for uplink multiuser massive multiple-input and multiple-output (MIMO) systems is the data detection problem at the receiver due to the substantial increase in the dimensions of MIMO systems. The optimal maximum likelihood detector is impractical for such large wireless systems, because it suffers from exponential complexity in terms of the number of users. Therefore, suboptimal alternatives with reduced complexity, such as the linear minimum mean square error (LMMSE) detector, are necessary. However, the LMMSE detector still introduces high computational complexity, mainly caused by the computation of the Gram matrix and matrix inversion. To reduce the computational complexity of data detection while achieving satisfactory bit error rate (BER) performance, we initially proposed an iterative data detection algorithm that exploits the coordinate descent method (CDM)-based algorithmic framework for uplink multiuser massive MIMO systems. We then developed a reduced-complexity hardware implementation algorithm by leveraging the “one-at-a-time” update property of the CDM-based algorithmic framework. Simulation results revealed that the proposed CDM-based detector provides the same or improved BER performance than the classical LMMSE algorithm at a lower complexity for different test scenarios. Auteurs: Jung-Chieh Chen; Apparue dans: IEEE Journal on Selected Areas in Communications Date publication: 08.-2017, volume: 35, issue:8, pages: 1701 - 1714 Editeur: IEEE Document complet vers site de l'éditeur
» A Low Phase Noise VCO Based on Substrate-Integrated Suspended Line Technology
 Résumé:This letter presents a low phase noise voltage-controlled oscillator (VCO) based on substrate-integrated suspended line (SISL) technology. With the proposed SISL technology, high-Q resonators and inductors can be realized to improve the phase noise performance. In addition, a transformed radial stub resonator is adopted to stabilize frequency and to make the circuit compact at the same time. The designed VCO achieved a phase noise of −132 dBc/Hz at 1-MHz offset from a 4.16-GHz carrier with an output power around 4.6 dBm. And the VCO size is only $28.94 \times 20.75$ mm2. Compared to other board level VCOs, this design has low phase noise, low power consumption, and compact size with the features of self-package simultaneously. Auteurs: Pei Zou;Kaixue Ma;Shouxian Mou; Apparue dans: IEEE Microwave and Wireless Components Letters Date publication: 08.-2017, volume: 27, issue:8, pages: 727 - 729 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Complexity Multiuser Coding Scheme With Near-Capacity Performance
 Résumé:Nonorthogonal multiuser coding is an essential technique for superimposed transmission and improving spectrum efficiency of future wireless communication networks. In this paper, a low-complexity nonorthogonal coding scheme, called multiuser repetition-aided irregular repeat-accumulate (IRA) code, is proposed for a multiple access channel (MAC), and the scheme can be applied to fifth-generation (5G) nonorthogonal multiple access systems. The main idea is that not only parity checks, which are generated by an IRA encoder, but repetitions as well, are used in each user's codeword to reduce the coding and decoding complexities. Repetition is a simple way to construct a low-rate code and is shown to be beneficial for multiuser decoding iteration. With a deliberate control of the fraction of repetitions in the codeword and a degree distribution optimization of the IRA encoder, near MAC capacity performance is achieved. It is shown that as the number of users increases, more repetitions can be used, and therefore, very low encoding and decoding complexities are required. Auteurs: Guanghui Song;Xianbin Wang;Jun Cheng; Apparue dans: IEEE Transactions on Vehicular Technology Date publication: 08.-2017, volume: 66, issue:8, pages: 6775 - 6786 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Temperature External Electron Retarding Electrode for Improving Vertical Green LED Performance
 Résumé:To alleviate the mismatch between electron/hole velocities and improve the quantum efficiencies, the cobalt-doped ZnO (CZO) dilute magnetic films grown by pulsed-laser deposition at a low temperature of 100 °C were served as the external electron retarding n-electrodes for vertical InGaN light-emitting diodes (LEDs). The retardation of the electron mobility is owing to the scatter of electrons via the spin-orbit interaction of Co2+ ions and their corresponding ferromagnetic properties. A 150-nm-thick CZO film was chosen as the n-electrode for the vertical green LED (530 nm). In comparison to conventional lateral LED, the vertical LEDs without and with the CZO n-electrode had 21.3% and 39.6% improvements in the output power (at 350 mA), respectively. The vertical LED with the CZO n-electrode showed an increment in the light output power (at 350 mA) by 15.1% as compared with the vertical LED without the CZO n-electrode. Obviously, after inserting the CZO n-electrode, the excessively large mobility difference between the electron and hole carriers in the conventional vertical LED is reduced significantly, which can decrease the nonradiative recombination rate and improve the emission characteristic. The results also reveal the CZO film served as an external electron retarding electrode is highly potential for vertical LED applications. Auteurs: Ching-Ho Tien;Sin-Liang Ou;Yi OuYang;Chien-Ming Chen;Dong-Sing Wuu; Apparue dans: IEEE Transactions on Electron Devices Date publication: 08.-2017, volume: 64, issue:8, pages: 3219 - 3225 Editeur: IEEE Document complet vers site de l'éditeur
» A Low-Voltage Folded-Switching Mixer Using Area-Efficient CCG Transconductor
 Résumé:This brief presents a low-voltage folded-switching mixer in 65-nm CMOS process. A modified complimentary common gate pair is utilized as the input transconductance stage, where a transformer is subtly applied for chip size reduction. Benefitted from the current reuse, the pMOS transistor not only works for radio frequency (RF) signal amplification, but also acts as the current bleeding path. This improves the conversion gain (CG), benefits the noise figure, and merits the mixer applicable in low-supply voltage. An inductive peaking scheme is also employed to further improve the CG and broaden the gain bandwidth. The presented mixer works under a low-supply voltage of 1 V and occupies an active area of only 0.24 mm2. Measured results exhibit the CG of 10.5 dB with 3-dB bandwidth ranging from 4 to 8.8 GHz, double-sideband noise figure from 3.8 to 5.2 dB, input return loss lower than −8.1 dB, and LO-to-RF isolation better than 46 dB. Auteurs: Pei Qin;Quan Xue; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 08.-2017, volume: 64, issue:8, pages: 877 - 881 Editeur: IEEE Document complet vers site de l'éditeur
» A Majorization–Minimization Approach for Reducing Out-of-Band Radiations in OFDM Systems
 Résumé:This letter is concerned with the reduction of the out-of-band (OOB) components in spectrum of orthogonal frequency division multiplexing (OFDM) systems. We propose an efficient method to obtain a phase sequence that is required in a phase adjustment algorithm, an algorithm which reduces the OOB components by employing proper phase shifts in OFDM symbols. The proposed method is based on the majorization–minimization technique, and converges to stationary points of an NP-hard design problem (under some mild conditions). Simulation results illustrate that the proposed method outperforms its counterparts in view of the solution quality as well as the computational complexity. Auteurs: Mohammad Mahdi Naghsh;Ehsan Haj Mirza Alian;Shahin Khobahi;Omid Rezaei; Apparue dans: IEEE Communications Letters Date publication: 08.-2017, volume: 21, issue:8, pages: 1739 - 1742 Editeur: IEEE Document complet vers site de l'éditeur
» A Manufacturing Big Data Solution for Active Preventive Maintenance
 Résumé:Industry 4.0 has become more popular due to recent developments in cyber-physical systems, big data, cloud computing, and industrial wireless networks. Intelligent manufacturing has produced a revolutionary change, and evolving applications, such as product lifecycle management, are becoming a reality. In this paper, we propose and implement a manufacturing big data solution for active preventive maintenance in manufacturing environments. First, we provide the system architecture that is used for active preventive maintenance. Then, we analyze the method used for collection of manufacturing big data according to the data characteristics. Subsequently, we perform data processing in the cloud, including the cloud layer architecture, the real-time active maintenance mechanism, and the offline prediction and analysis method. Finally, we analyze a prototype platform and implement experiments to compare the traditionally used method with the proposed active preventive maintenance method. The manufacturing big data method used for active preventive maintenance has the potential to accelerate implementation of Industry 4.0. Auteurs: Jiafu Wan;Shenglong Tang;Di Li;Shiyong Wang;Chengliang Liu;Haider Abbas;Athanasios V. Vasilakos; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 08.-2017, volume: 13, issue:4, pages: 2039 - 2047 Editeur: IEEE Document complet vers site de l'éditeur
» A Markov-Based Update Policy for Constantly Changing Database Systems
 Résumé:In order to maximize the value of an organization's data assets, it is important to keep data in its databases up-to-date. In the era of big data, however, constantly changing data sources make it a challenging task to assure data timeliness in enterprise systems. For instance, due to the high frequency of purchase transactions, purchase data stored in an enterprise resource planning system can easily become outdated, affecting the accuracy of inventory data and the quality of inventory replenishment decisions. Despite the importance of data timeliness, updating a database as soon as new data arrives is typically not optimal because of high update cost. Therefore, a critical problem in this context is to determine the optimal update policy for database systems. In this study, we develop a Markov decision process model, solved via dynamic programming, to derive the optimal update policy that minimizes the sum of data staleness cost and update cost. Based on real-world enterprise data, we conduct experiments to evaluate the performance of the proposed update policy in relation to benchmark policies analyzed in the prior literature. The experimental results show that the proposed update policy outperforms fixed interval update policies and can lead to significant cost savings. Auteurs: Wei Zong;Feng Wu;Zhengrui Jiang; Apparue dans: IEEE Transactions on Engineering Management Date publication: 08.-2017, volume: 64, issue:3, pages: 287 - 300 Editeur: IEEE Document complet vers site de l'éditeur
» A MATLAB-Based Virtual Tool for Simulations of Wave Propagation Inside a Parallel-Plate Waveguide [Testing Ourselves]
 Résumé:A MATLAB-based propagation tool called plate graphical user interface (PlateGUI), which calculates and shows electromagnetic (EM) fields inside a parallel-plate waveguide using different analytical and numerical models, was developed and is discussed in this article. PlateGUI can be used in graduate-level courses that deal with guided-wave theory and computational electromagnetics (CEM). Auteurs: Gokhan Apaydin;Levent Sevgi; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 08.-2017, volume: 59, issue:4, pages: 100 - 105 Editeur: IEEE Document complet vers site de l'éditeur
» A Mean Field Analysis of CSMA/CA Throughput
 Résumé:Due to the fact that Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocols are extensively used in commercial wireless networks, the analysis of this family of medium access control protocols has been a topic of great interest for the wireless networking community. In this paper, we present a mean field analysis for the throughput of a slotted CSMA/CA scheme in single-hop networks. The concept of mean field approximation originates in statistical mechanics and it is a widely used approximation method employed to address systems of many interacting particles that cannot be solved exactly. The idea is to simplify the treatment of a many-body system by describing the interaction of one particle with the other interacting particles by an average potential, the so-called mean field. In our analysis, the nodes of a wireless network constitute a set of interacting particles; the interaction of a certain node with the other nodes in the network is reduced to an averaged channel condition. We estimate the amount of busy slots and the network throughput with respect to the offered traffic. Our analysis is of a recursive form, in which at each step the amount of traffic is increased by a specific amount. Also, our model takes into accounts retransmissions of collided packets. Auteurs: Maria Michalopoulou;Petri Mähönen; Apparue dans: IEEE Transactions on Mobile Computing Date publication: 08.-2017, volume: 16, issue:8, pages: 2093 - 2104 Editeur: IEEE Document complet vers site de l'éditeur
» A MEMS Fishbone-Shaped Electrostatic Double-Ended Tuning Fork Resonator With Selectable Higher Modes
 Résumé:In this paper, a microelectromechanical systems fishbone-shaped electrostatic double-ended tuning fork (DETF) resonator with selectable higher modes is presented. The resonator can realize ten vibration modes with resonant frequencies from 137.929 to 913.476 kHz and multi-mode selection function. Different from conventional electrostatic actuation methods, the proposed fishbone-shaped structure combined with tooth-shaped electrode generates bending moment on the beam and leads to vibration of the DETF. The vibration mode and the resonant frequency can be selected and measured according to the configuration of electrodes. Consequently, the proposed fishbone-shaped DETF resonator can provide multi-mode vibration and variable resonant frequency. The device is fabricated by the silicon-on-insulator process and tested via open-loop spectral response measurement. Finally, electrical parameters of the equivalent circuit model are extracted for further research. [2016-0315] Auteurs: Hong Ding;Xianhao Le;Jin Xie; Apparue dans: Journal of Microelectromechanical Systems Date publication: 08.-2017, volume: 26, issue:4, pages: 793 - 801 Editeur: IEEE Document complet vers site de l'éditeur
» A Method for Estimation of Functional Dependence of Injection Charge Formation on Electric Field Strength
 Résumé:The improvement of electrohydrodynamic devices is hindered by the absence of necessary information on the functional dependence of injection current density on the electric field strength. The investigation of the issue presents a great challenge because the quantity measured experimentally is the total current that is dependent on some almost inseparable factors. Moreover, the present theoretical dependences contradict each other and have not been verified by the experiment. In view of this, the determination of injection function is an actual problem, and the paper is an attempt to solve it. The approach proposed here is based on a comparison of the so-called dynamical current–voltage characteristics, resulting from the experiment and computer simulation where a test injection function is used as a boundary condition and changed iteratively. The correctness of the final injection function was confirmed by good agreement of the velocity distributions obtained from computer simulation and the particle image velocimetry experiment. Auteurs: Albert Gazaryan;Andrei Sitnikov;Vladimir Chirkov;Yury Stishkov; Apparue dans: IEEE Transactions on Industry Applications Date publication: 08.-2017, volume: 53, issue:4, pages: 3977 - 3981 Editeur: IEEE Document complet vers site de l'éditeur
» A Microfluidic Cytometer for Complete Blood Count With a 3.2-Megapixel, 1.1- μm-Pitch Super-Resolution Image Sensor in 65-nm BSI CMOS
 Résumé:Based on a 3.2-Megapixel 1.1- μm-pitch super-resolution (SR) CMOS image sensor in a 65-nm backside-illumination process, a lens-free microfluidic cytometer for complete blood count (CBC) is demonstrated in this paper. Backside-illumination improves resolution and contrast at the device level with elimination of surface treatment when integrated with microfluidic channels. A single-frame machine-learning-based SR processing is further realized at system level for resolution correction with minimum hardware resources. The demonstrated microfluidic cytometer can detect the platelet cells (< 2 μm) required in CBC, hence is promising for point-of-care diagnostics. Auteurs: Xu Liu;Xiwei Huang;Yu Jiang;Hang Xu;Jing Guo;Han Wei Hou;Mei Yan;Hao Yu; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 08.-2017, volume: 11, issue:4, pages: 794 - 803 Editeur: IEEE Document complet vers site de l'éditeur
» A Miniaturized 0.78-mW/cm2 Autonomous Thermoelectric Energy-Harvesting Platform for Biomedical Sensors
 Résumé:In order to use thermoelectric energy harvesters (TEHs) as a truly autonomous energy source for size-limited sensing applications, it is essential to improve the power conversion efficiency and energy density. This study presents a thin-film, array-based TEH with a surface area of 0.83 cm2. The TEH autonomously supplies a power management IC fabricated in a 65-nm CMOS technology. The IC utilizes a single-inductor topology with integrated analog maximum power point tracking (MPPT), resulting in a 68% peak end-to-end efficiency (92% converter efficiency) and less than 20-ms MPPT. In an in-vivo test, a 645-μW regulated output power (effective 3.5 K of temperature gradient) was harvested from a rat implanted with our TEH, demonstrating true energy independence in a real environment while showing a 7.9 × improvement in regulated power density compared to the state-of-the-art. The system showed autonomous operation down to 65-mV TEH input. Auteurs: Dejan Rozgić;Dejan Marković; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 08.-2017, volume: 11, issue:4, pages: 773 - 783 Editeur: IEEE Document complet vers site de l'éditeur
» A mm-Wave Patch Antenna with Broad Bandwidth and a Wide Angular Range
 Résumé:A novel mm-wave microstrip-fed patch antenna with broad bandwidth and wide angular coverage suitable for integration in planar arrays is designed, analyzed, and verified by measurements. The antenna provides a bandwidth of 13.1% between 34.1 and 38.9 GHz, which is achieved by a slotted multiple resonances microstrip patch and a matching circuit in microstrip technology. The antenna is built on RO3003 substrate with top and ground layers, which is low cost compared with other techniques. For simple integration with microstrip and frontend circuits, the feeding happens at the top layer with a microstrip coupling gap feed. The wide half-power beamwidth (HPBW) is achieved by suitably designed parasitic patches for the first resonant mode. The second resonant mode has a wide HPBW by default. The HPBW is between 100° and 125° within the matched bandwidth, which is a very good value for a microstrip patch antenna radiating over a ground plane. The measured input impedance and radiation characteristic show very good agreement with simulation results. Auteurs: Jonas Kornprobst;Kun Wang;Gerhard Hamberger;Thomas F. Eibert; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 08.-2017, volume: 65, issue:8, pages: 4293 - 4298 Editeur: IEEE Document complet vers site de l'éditeur
» A mmWave Folded Substrate Integrated Waveguide in a 130-nm CMOS Process
 Résumé:A miniaturized millimeter-wave substrate integrated waveguide (SIW) in IBM 130-nm digital CMOS process is presented in this paper. The footprint of the interconnect is reduced compared with previous works using the folding technique. A current-loop transition structure is proposed in this paper that is built inside the SIW interconnect and excites its TE10 mode with minimal area overhead. A simulation-based comparison of T-FSIW and other planar transmission line structures reveals that the T-FSIW interconnect shows a much higher resonant quality factor. A prototype waveguide is designed and fabricated to operate with a cutoff frequency of 175 GHz. Furthermore, the current-loop excitation is optimized for the frequency range of 180–220 GHz. Simulation and experimental data are used to confirm the proposed interconnect approach. Auteurs: Mohammad Shahidzadeh Mahani;Gordon W. Roberts; Apparue dans: IEEE Transactions on Microwave Theory and Techniques Date publication: 08.-2017, volume: 65, issue:8, pages: 2775 - 2788 Editeur: IEEE Document complet vers site de l'éditeur
» A Mostly Digital VCO-Based CT-SDM With Third-Order Noise Shaping
 Résumé:This paper presents the architectural concept and implementation of a mostly digital voltage-controlled oscillator-analog-to-digital converter (VCO-ADC) with third-order quantization noise shaping. The system is based on the combination of a VCO and a digital counter. It is shown how this combination can function as a continuous-time integrator to form a high-order continuous-time sigma–delta modulator (CT-SDM). The counter consists only of digital building blocks, and the VCOs are implemented using ring oscillators, which are also digital-friendly. No traditional analog blocks, such as opamps, OTAs, or comparators, are used. As a proof of concept, we have implemented a third-order VCO-based CT-SDM for a 10-MHz bandwidth in the low-power version of a 65-nm CMOS technology. This prototype shows a measured performance of 71/66.2/62.5-dB DR/SNR/SNDR at a 10-MHz bandwidth while consuming 1.8 mW from a 1.0-V analog and 1.9 mW from a 1.2-V digital supply. With digital calibration, the nonlinearity could be pushed below the noise level, leading to an improved peak SNDR of 66 dB. Auteurs: Amir Babaie-Fishani;Pieter Rombouts; Apparue dans: IEEE Journal of Solid-State Circuits Date publication: 08.-2017, volume: 52, issue:8, pages: 2141 - 2153 Editeur: IEEE Document complet vers site de l'éditeur
» A Multi-linear Polarization Reconfigurable Unidirectional Patch Antenna
 Résumé:A novel multi-linear polarization (multi-LP) reconfigurable unidirectional circular patch antenna is proposed, which can switch among four LPs at every 45° rotation. The patch antenna is fed in the center and shorting posts are used to excite TM11 mode with LP. By controlling the connections between the four shorting posts and the ground plane using p-i-n diodes, four reconfigurable polarization states at $\phi =0 {^{\circ }}$ , $\phi =45 {^{\circ }}$ , $\phi =90 {^{\circ }}$ , or $\phi =135 {^{\circ }}$ can be realized. The size of this antenna is about $0.57\lambda \times 0.57\lambda \times 0.07\lambda$ at 2.45 GHz. It can be easily fabricated and has a simple biasing network. The measured overlapping impedance bandwidth for different polarizations under the condition $|\text{S}11| \leq -10$ dB is from 2.33 to 2.50 GHz, which agrees well with the simulated one. Moreover, the antenna maintains stable radiation patterns and the measured realized gains range from 5.3 to 5.9 dBi. Auteurs: Shu-Lin Chen;Feng Wei;Pei-Yuan Qin;Y. Jay Guo;Xi Chen; Apparue dans: IEEE Transactions on Antennas and Propagation Date publication: 08.-2017, volume: 65, issue:8, pages: 4299 - 4304 Editeur: IEEE Document complet vers site de l'éditeur
» A Multiband, Mutipolarization Shared-Aperture Antenna: Design and evaluation.
 Résumé:A compact, shared-aperture antenna (SAA) configuration consisting of various planar antennas embedded into a single footprint is presented in this article. An L-probefed, suspended-plate, horizontally polarized antenna operating in an 900-MHz band; an aperture-coupled, vertically polarized, microstrip antenna operating at 4.2-GHz; a 2 × 2 microstrip patch array operating at the X band; a low-side-lobe level (SLL), corporate-fed, 8 × 4 microstrip planar array for synthetic aperture radar (SAR) in the X band; and a printed, single-arm, circularly polarized, tilted-beam spiral antenna operating at the C band are integrated into a single aperture for simultaneous operation. This antenna system could find potential application in many airborne and unmanned aircraft vehicle (UAV) technologies. While the design of these antennas is not that critical, their optimal placement in a compact configuration for simultaneous operation with minimal interference poses a significant challenge to the designer. The placement optimization was arrived at based on extensive numerical fullwave optimizations. Auteurs: Patnam H. Rao;Sathiyamoorthy Sujitha;Krishnasamy T. Selvan; Apparue dans: IEEE Antennas and Propagation Magazine Date publication: 08.-2017, volume: 59, issue:4, pages: 26 - 37 Editeur: IEEE Document complet vers site de l'éditeur
» A Multimodal Framework Based on Integration of Cortical and Muscular Activities for Decoding Human Intentions About Lower Limb Motions
 Résumé:In this study, a multimodal fusion framework based on three different modal biosignals is developed to recognize human intentions related to lower limb multi-joint motions which commonly appear in daily life. Electroencephalogram (EEG), electromyogram (EMG) and mechanomyogram (MMG) signals were simultaneously recorded from twelve subjects while performing nine lower limb multi-joint motions. These multimodal data are used as the inputs of the fusion framework for identification of different motion intentions. Twelve fusion techniques are evaluated in this framework and a large number of comparative experiments are carried out. The results show that a support vector machine-based three-modal fusion scheme can achieve average accuracies of 98.61%, 97.78% and 96.85%, respectively, under three different data division forms. Furthermore, the relevant statistical tests reveal that this fusion scheme brings significant accuracy improvement in comparison with the cases of two-modal fusion or only a single modality. These promising results indicate the potential of the multimodal fusion framework for facilitating the future development of human-robot interaction for lower limb rehabilitation. Auteurs: Chengkun Cui;Gui-Bin Bian;Zeng-Guang Hou;Jun Zhao;Hao Zhou; Apparue dans: IEEE Transactions on Biomedical Circuits and Systems Date publication: 08.-2017, volume: 11, issue:4, pages: 889 - 899 Editeur: IEEE Document complet vers site de l'éditeur
» A Necessary and Sufficient Condition for a Resource Subset to Generate a Strict Minimal Siphon in S 4PR
 Résumé:Systems of sequential systems with shared resources (S4PR) represent a class of Petri nets that have powerful modeling capability for resource allocation systems. Their efficient siphon computation is important. An open issue is how to determine whether a resource subset can generate a strict minimal siphon (SMS). This paper presents the answer. In particular, we propose a new concept called characteristic implicit resource-transition nets. By charactering such nets, we successfully establish a necessary and sufficient condition for a resource subset to generate an SMS. Auteurs: ShouGuang Wang;Dan You;MengChu Zhou; Apparue dans: IEEE Transactions on Automatic Control Date publication: 08.-2017, volume: 62, issue:8, pages: 4173 - 4179 Editeur: IEEE Document complet vers site de l'éditeur
» A New Active Disturbance Rejection Control to Output Feedback Stabilization for a One-Dimensional Anti-Stable Wave Equation With Disturbance
 Résumé:The disturbance estimate is the central idea of active disturbance rejection control (ADRC), where the disturbance is estimated via extended state observer (ESO). However, the conventional ESO requires the disturbance to have slow variation and in order to counteract such disturbance, the ESO must use high gain or discontinuous function. In this paper, we demonstrate for the first time, through a one-dimensional anti-stable wave system, the online disturbance estimation by designing an infinite-dimensional disturbance estimator. We go back to the starting point of ADRC that the exactly observable output allows identification of the disturbance which can thereupon be estimated. This realizes the estimation/cancellation strategy of ADRC in a very different way without resorting conventional ESO. We do not regard the disturbance as an “extra-state” variable in the ESO, and hence avoid the two limitations of the ESO. Since the disturbance is estimated, it can be compensated in the feedback loop. It is shown that the disturbance estimator-based feedback control can successfully stabilize the PDE system and at the same time guarantees that all subsystems involved are uniformly bounded. A numerical simulation is presented to illustrate the effectiveness of the the proposed scheme. Auteurs: Hongyinping Feng;Bao-Zhu Guo; Apparue dans: IEEE Transactions on Automatic Control Date publication: 08.-2017, volume: 62, issue:8, pages: 3774 - 3787 Editeur: IEEE Document complet vers site de l'éditeur
» A New Air Pollution Source Identification Method Based on Remotely Sensed Aerosol and Improved Glowworm Swarm Optimization
 Résumé:Air pollution sources generally cannot be identified as the specific factories but certain industries. Focusing on this issue, a new method, based on an improved glowworm swarm optimization and remotely sensed imagery, was proposed to precisely orientate and quantify air pollution sources in this study. In addition, meteorological data and GIS information were also used to backtrack the pollution source. After that, in order to quantify the pollution of each factory in the study areas, three pollution indices, pollution gross (PG), pollution intensity, and area-normalized pollution (ANP), were proposed. As a result, the polluting contribution of each factory was listed, and the most polluting factories, which were bulletined as the key monitoring factories by the local authority, were accurately extracted. Among the pollution indices, ANP is the most robust, reliable, and recommended. Furthermore, the result also shows factory pollution background information achieved from the historical remote sensing data which can be used to improve the precision of identification. To our knowledge, this study provides the first attempt to address the problem of identifying a pollution source as originating from an individual factory based on remote sensing data. The proposed method provides a useful tool for air quality management, and the result would be meaningful to environmental and economic issue. Auteurs: Yunping Chen;Shudong Wang;Weihong Han;Yajv Xiong;Wenhuan Wang;Ling Tong; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 08.-2017, volume: 10, issue:8, pages: 3454 - 3464 Editeur: IEEE Document complet vers site de l'éditeur
» A New Algorithm for Surface Currents Inversion With High-Frequency Over-the-Horizon Radar
 Résumé:The conventional method of extracting ocean surface currents by high-frequency over-the-horizon radar is based on the fixed first-order Bragg frequency formula and ignores the effects caused by the environment, especially in near-shore areas. In this letter, a current inversion model based on 2-D Fourier series expansion was developed. The first-order Bragg frequency and the Doppler offset induced by radial current are dealt with the bivariate functions of group distance and azimuth angle in the proposed method. By solving an overdetermined matrix equation with the least-square fitting method, the current at each detection grid can be estimated. As the Bragg frequency obtained by this new algorithm is adaptive to the environment, the accuracy of current measurement will be improved. The feasibility and effectiveness of the new method are verified with simulations and experimental results. The currents estimated by the traditional method and the new algorithm are compared with two in situ buoys. Results indicate that the new algorithm possesses comparable accuracy for far-shore areas and better accuracy for near-shore areas when compared with the conventional method. Auteurs: Miao Li;Xiongbin Wu;Lan Zhang;Xianchang Yue;Chuan Li;Jianfei Liu; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 08.-2017, volume: 14, issue:8, pages: 1303 - 1307 Editeur: IEEE Document complet vers site de l'éditeur
» A New Analytical Model to Study the Ionospheric Effects on VHF/UHF Wideband SAR Imaging
 Résumé:With a view to detecting foliage-obscured/ground-obscured targets on a global scale, low frequency (i.e., very high frequency (VHF)/ultrahigh frequency (UHF) band) and wide bandwidth is a trend in future spaceborne synthetic aperture radar (SAR) system design. However, due to the dispersion of ionosphere, VHF/UHF wide bandwidth SAR signals inevitably experience adverse effects. In contrast to narrow bandwidth SAR at VHF/UHF, quadratic and cubic ionospheric phase errors will introduce noticeable effects on future wide-bandwidth SAR systems. Traditional evaluation models based on Taylor series expansion may become inaccurate when an extremely wide bandwidth is considered. With a focus on this this issue, first, the shortcoming of Taylor series expansion of ionospheric phase errors is briefly discussed in this paper. Then, a new analytical model based on Legendre orthogonal polynomials is developed, which is expected to be widely applicable, especially for low-frequency and wide-bandwidth SAR systems. Finally, compared with previous models based on Taylor series expansion, numerical simulations and evaluations show the superiority of the new model. Auteurs: Cheng Wang;Liang Chen;Lu Liu; Apparue dans: IEEE Transactions on Geoscience and Remote Sensing Date publication: 08.-2017, volume: 55, issue:8, pages: 4545 - 4557 Editeur: IEEE Document complet vers site de l'éditeur
» A New Block-Based Method for HEVC Intra Coding
 Résumé:This paper presents a new block-based method for the High Efficiency Video Coding (HEVC) intra coding. First, we have found through analysis and test that the prediction errors on some pixels in each prediction block (PB) that are neighboring to the reference pixels would be no bigger than the corresponding coding errors. Based on this observation, the pixels in each PB are divided into two parts: half pixels are coded via a novel padding technique together with a constrained quantization algorithm (leading to around 3 dB gain under the same bit rate), whereas the other half are reconstructed by linear interpolations along a prediction direction by utilizing the neighboring reference pixels and the first half coded pixels. In the final implementation, a competition mechanism is employed between this new method and the original HEVC intra coding in order to choose the best mode for each PB. Experimental results show that about 2% BD-rate reduction has been achieved both for luma and chroma with respect to the original HEVC intra coding, whereas the encoder complexity increases by 130%, but the decoding time remains nearly unchanged. Auteurs: Chen Chen;Shuyuan Zhu;Bing Zeng;Moncef Gabbouj; Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology Date publication: 08.-2017, volume: 27, issue:8, pages: 1727 - 1736 Editeur: IEEE Document complet vers site de l'éditeur
» A New Construction of Exact-Repair MSR Codes Using Linearly Dependent Vectors
 Résumé:Regenerating codes focus on the efficient repair of node failures. In an [ $n$ , $k$ , $d$ ] regenerating code system, any $k$ nodes can retrieve the original data and any $d$ nodes can repair a failed node by giving out $\beta$ pieces of data per node. For minimum storage regenerating (MSR) codes, ${d \geq 2 k - 3}$ has been proved. However, as far as we know, there is no construction of exact-repair MSR codes with ${d= 2 k - 3}$ and ${\beta = 1}$ at present. In this letter, we give the first construction of [6, 4, 5] MSR codes with ${\beta = 1}$ , which can perform exact repair of all nodes. Employing the technique of linearly dependent vectors, our codes can be constructed over a small finite field ${F_{4}}$ . Auteurs: Sheng Guan;Haibin Kan;Jie Wen;Shuli Xia; Apparue dans: IEEE Communications Letters Date publication: 08.-2017, volume: 21, issue:8, pages: 1691 - 1694 Editeur: IEEE Document complet vers site de l'éditeur
» A New FXLMS Algorithm With Offline and Online Secondary-Path Modeling Scheme for Active Noise Control of Power Transformers
 Résumé:In this study, the active noise control (ANC) method was used to suppress high-decibel and low-frequency power transformer noise. An appropriate ANC system was selected based on the transformer noise characteristics and experimental condition. A new filter-X least mean square (FXLMS) adaptive ANC algorithm based on offline and online secondary-path modeling was proposed to realize faster and more stable secondary-path online modeling than that of the random white-noise FXLMS algorithm and to ensure the convergence, stability, and reduction in transformer noise control. Moreover, the genetic algorithm is adopted to optimize the convergence coefficient, while the effect of the convergence coefficient on the algorithm was analyzed using simulation and theory. In addition, the transformer noise online monitoring and active control system was designed including software and hardware, and the hardware devices were selected based on the noise feature. In the 50 000 KVA transformer noise reduction experiment, the system achieved a noise reduction of 8–15 dB and an 84.10–96.86% decrease in average sound energy density in a certain area. Auteurs: Tong Zhao;Jiabi Liang;Liang Zou;Li Zhang; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 08.-2017, volume: 64, issue:8, pages: 6432 - 6442 Editeur: IEEE Document complet vers site de l'éditeur
» A New Interpretation for the Anomalous Channel-Length Dependence of Low-Frequency Noise in Quasi-Ballistic Transistors
 Résumé:The operating regime of MOS transistors shifts from collision-dominated drift-diffusion (DD) to less-collision quasi-ballistic (QB) regime. The impact of transport mechanism on the low-frequency noise (LFN) is not well studied for QB devices. Most of the studies rely on the existing theories that were developed for DD-based devices to study LFN even in nanoscale regime. Validity of these models is questionable. In this letter, we extend the conventional carrier-number and correlated-mobility fluctuation model to the QB regime. The model is in accordance with the “apparent mean free path” $(\lambda _{\textit {app}})$ model, which predicts scattering limited noise mechanism in the QB regime. The model is validated with LFN measurement data for III-V QB devices, and shows good agreement with the expected behavior. Auteurs: Arjun Ajaykumar;Xing Zhou;Siau Ben Chiah; Apparue dans: IEEE Electron Device Letters Date publication: 08.-2017, volume: 38, issue:8, pages: 1113 - 1116 Editeur: IEEE Document complet vers site de l'éditeur
» A New Modulation Transfer Function With Range and Azimuth Dependence for Ocean Wave Spectra Retrieval From X-Band Marine Radar Observations
 Résumé:The conventional linear modulation transfer function (MTF) was derived using HH-polarized marine radar observations in deepwater conditions. It is possible to constrain this MTF for ocean surface wave spectra retrieval in coastal shallow waters. In this letter, we propose a new MTF with both range and azimuth dependence based on VV-polarized radar measurements acquired from heterogeneous coastal wave fields. This new MTF is determined using a radar-observed image spectrum and in situ buoy-measured wave frequency spectrum. To assess the proposed MTF, we compare the buoy-measured 1-D wavenumber spectrum with those obtained using different MTFs. Compared to the conventional linear MTF, the new MTF-derived wavenumber spectrum is closer to buoy measurements. The retrieved peak and mean wave periods are also validated using concurrent wave buoy measurements. It is shown that the retrieval accuracies of peak and mean wave periods of the new MTF are better than those of the conventional MTF. The bias and root mean square errors of the peak and mean wave periods of the new MTF are 0.52 and 0.95 s and 0.26 and 0.48 s, respectively. This suggests that the proposed new MTF is more appropriate for retrieving integral wave parameters than the conventional linear MTF. Auteurs: Jidong Qiu;Biao Zhang;Zhongbiao Chen;Yijun He; Apparue dans: IEEE Geoscience and Remote Sensing Letters Date publication: 08.-2017, volume: 14, issue:8, pages: 1373 - 1377 Editeur: IEEE Document complet vers site de l'éditeur
» A New Statistical Model of Electroencephalogram Noise Spectra for Real-Time Brain–Computer Interfaces
 Résumé:Objective: A characteristic of neurological signal processing is high levels of noise from subcellular ion channels up to whole-brain processes. In this paper, we propose a new model of electroencephalogram (EEG) background periodograms, based on a family of functions which we call generalized van der Ziel-McWhorter (GVZM) power spectral densities (PSDs). To the best of our knowledge, the GVZM PSD function is the only EEG noise model that has relatively few parameters, matches recorded EEG PSD's with high accuracy from 0 to over 30 Hz, and has approximately 1/fθ behavior in the midfrequencies without infinities. Methods: We validate this model using three approaches. First, we show how GVZM PSDs can arise in a population of ion channels at maximum entropy equilibrium. Second, we present a class of mixed autoregressive models, which simulate brain background noise and whose periodograms are asymptotic to the GVZM PSD. Third, we present two real-time estimation algorithms for steady-state visual evoked potential (SSVEP) frequencies, and analyze their performance statistically. Results: In pairwise comparisons, the GVZM-based algorithms showed statistically significant accuracy improvement over two well-known and widely used SSVEP estimators. Conclusion: The GVZM noise model can be a useful and reliable technique for EEG signal processing. Significance: Understanding EEG noise is essential for EEG-based neurology and applications such as real-time brain-computer interfaces, which must make accurate control decisions from very short data epochs. The GVZM approach represents a successful new paradigm for understanding and managing this neurological noise. Auteurs: Alan Paris;George K. Atia;Azadeh Vosoughi;Stephen A. Berman; Apparue dans: IEEE Transactions on Biomedical Engineering Date publication: 08.-2017, volume: 64, issue:8, pages: 1688 - 1700 Editeur: IEEE Document complet vers site de l'éditeur
» A New Upper Bound on the Achievable Rate of Relay Channel With MIP-QF Strategy
 Résumé:Recently, a new mutual information preserving quantize-and-forward (MIP-QF) is proposed for the half-duplex relay channel, where the relay node does not need to decode the source signal correctly. In this paper, a new MIP-QF upper bound on the achievable rate of the half-duplex relay channel is proposed, which is shown to be lying between the compress-and-forward (CF) bound and the cut-set bound. For the half-duplex additive white Gaussian noise (AWGN) relay channel, the specific MIP-QF bound and the optimal duplex ratios of the MIP-QF upper bound and the MMSE-CF bound are also derived. In addition, we also show that the decode-and-forward (DF) bound can exceed the MIP-QF bound in some special cases that the relay is close to the source and far away from the destination. The validity and accuracy of the proposed theoretical results are verified by numerical results under the half-duplex AWGN relay channel. Auteurs: Lei Liu;Yuzhu Liang;Ying Li; Apparue dans: IEEE Transactions on Vehicular Technology Date publication: 08.-2017, volume: 66, issue:8, pages: 6787 - 6800 Editeur: IEEE Document complet vers site de l'éditeur
» A Note on Recursive Schur Complements, Block Hurwitz Stability of Metzler Matrices, and Related Results
 Résumé:It is known that the stability of a Metzler matrix can be characterized in a Routh–Hurwitz-like fashion based on a recursive application of scalar Schur complements [1]. Our objective in this brief note is to show that recently obtained stability conditions are equivalent statements of this result and can be deduced directly therefrom using only elementary results from linear algebra. Implications of this equivalence are also discussed and several examples are given to illustrate potentially interesting system-theoretic applications of this observation. Auteurs: Matheus Souza;Fabian R. Wirth;Robert N. Shorten; Apparue dans: IEEE Transactions on Automatic Control Date publication: 08.-2017, volume: 62, issue:8, pages: 4167 - 4172 Editeur: IEEE Document complet vers site de l'éditeur
» A Note on Relationship Between Two Classes of Integral Inequalities
 Résumé:This technical note firstly introduces two classes of integral inequalities with and without free matrices, respectively, and points out that they, although in different forms, are actually equivalent in the sense of conservatism, i.e., the two corresponding ones produce the same tight upper bounds. Secondly, the relationship between the method of integral inequalities with free matrices and the free-weighting matrix technique is intensively investigated. It is shown that these two different methods are actually equivalent in assessing the stability of time-delay systems. Auteurs: Jun Chen;Shengyuan Xu;Baoyong Zhang;Guobao Liu; Apparue dans: IEEE Transactions on Automatic Control Date publication: 08.-2017, volume: 62, issue:8, pages: 4044 - 4049 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Adaptive Cuckoo Search Algorithm for Contrast Enhancement of Satellite Images
 Résumé:Owing to the increased demand for satellite images for various practical applications, the use of proper enhancement methods are inevitable. Visual enhancement of such images mainly focuses on improving the contrast of the scene procured, conserving its naturalness with minimum image artifacts. Last one decade traced an extensive use of metaheuristic approaches for automatic image enhancement processes. In this paper, a robust and novel adaptive Cuckoo search based Enhancement algorithm is proposed for the enhancement of various satellite images. The proposed algorithm includes a chaotic initialization phase, an adaptive $\mathbf L\acute{e}vy$ flight strategy and a mutative randomization phase. Performance evaluation is done by quantitative and qualitative results comparison of the proposed algorithm with other state-of-the-art metaheuristic algorithms. Box-and-whisker plots are also included for evaluating the stability and convergence capability of all the algorithms tested. Test results substantiate the efficiency and robustness of the proposed algorithm in enhancing a wide range of satellite images. Auteurs: Shilpa Suresh;Shyam Lal;Chintala Sudhakar Reddy;Mustafa Servet Kiran; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 08.-2017, volume: 10, issue:8, pages: 3665 - 3676 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel and Efficient Vector Quantization Based CPRI Compression Algorithm
 Résumé:The future wireless network, such as the Centralized Radio Access Network (C-RAN), will need to deliver data rate about 100–1000 times the current fourth-generation (4G) technology. For the C-RAN-based network architecture, there is a pressing need for tremendous enhancement of the effective data rate of the common public radio interface (CPRI). Compression of CPRI data is one of the potential enhancements. In this paper, we introduce a vector quantization based compression algorithm for CPRI links, utilizing the Lloyd algorithm. Methods to vectorize the I/Q samples and enhanced initialization of the Lloyd algorithm for codebook training are investigated for improved performance. Multistage vector quantization and unequally protected multigroup quantization are considered to reduce codebook search complexity and codebook size. Simulation results show that our solution can achieve compression of four times for uplink and 4.5 times for downlink, within $2\%$ error vector magnitude (EVM) distortion. Remarkably, vector quantization codebook proves to be quite robust against data modulation mismatch, fading, signal-to-noise ratio (SNR), and Doppler spread. Auteurs: Hongbo Si;Boon Loong Ng;Md. Saifur Rahman;Jianzhong Zhang; Apparue dans: IEEE Transactions on Vehicular Technology Date publication: 08.-2017, volume: 66, issue:8, pages: 7061 - 7071 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Approach for Improvement of Power Swing Blocking and Deblocking Functions in Distance Relays
 Résumé:Power swing conditions in power systems make distance relays take the wrong breaker action in some cases. In this context, power swing blocking and power swing deblocking are two important functions in distance relays so as to distinguish power swing from a fault, which maintains stability of system and continuity of the power supply. In this paper, a sample estimation and error calculation method based on Taylor Series expansion is proposed for improving power swing detection performance of the relay. Performance of the method is compared with four conventional methods and a novel method in literature. Analyses are carried out in two systems: single machine-infinite bus system with parallel lines and 68-bus New England test-New York power system for fault, power swing, and fault during power swing scenarios. Simulations and performance analyses are carried out by using EMTDC/PSCAD and MATLAB, respectively. According to the results, when performances in correct operation, algorithm response times, clarity of outputs, and time passed for program execution on processor are considered, the proposed method has the best performance overall. It is found that by using the proposed method, distance relay performance in correct operation and speed for taking power swing blocking and deblocking actions are improved. Auteurs: Ibrahim Gursu Tekdemir;Bora Alboyaci; Apparue dans: IEEE Transactions on Power Delivery Date publication: 08.-2017, volume: 32, issue:4, pages: 1986 - 1994 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Approach to Reliable Control of Piecewise Affine Systems With Actuator Faults
 Résumé:This brief is devoted to the reliable piecewise affine (PWA) $\mathscr {H}_{\infty }$ static output feedback control problem for PWA systems with actuator faults. The actuator faults are characterized by a Markov process. Specifically, by adopting a state-input augmentation technique, the original closed-loop system is first reformulated into a descriptor PWA system. On the basis of a piecewise-Markovian Lyapunov function, and by exploiting advantage of the redundancy of descriptor system formulation, together with a linearization procedure, the PWA controller synthesis is then presented. It is shown that the desired PWA controller parameters can be attained via solving a linear matrix inequality-based optimization problem. Finally, a simulation example is carried out to confirm the effectiveness and less conservatism of the developed approach. Auteurs: Jianbin Qiu;Yanling Wei;Ligang Wu; Apparue dans: IEEE Transactions on Circuits and Systems II: Express Briefs Date publication: 08.-2017, volume: 64, issue:8, pages: 957 - 961 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Embedding Method for Information Diffusion Prediction in Social Network Big Data
 Résumé:With the increase of social networking websites and the interaction frequency among users, the prediction of information diffusion is required to support effective generalization and efficient inference in the context of social big data era. However, the existing models either rely on expensive probabilistic modeling of information diffusion based on partially known network structures, or discover the implicit structures of diffusion from users’ behaviors without considering the impacts of different diffused contents. To address the issues, in this paper, we propose a novel information-dependent embedding-based diffusion prediction (IEDP) model to map the users in observed diffusion process into a latent embedding space, then the temporal order of users with the timestamps in the cascade can be preserved by the embedding distance of users. Our proposed model further learns the propagation probability of information in the cascade as a function of the relative positions of information-specific user embeddings in the information-dependent subspace. Then, the problem of temporal propagation prediction can be converted into the task of spatial probability learning in the embedding space. Moreover, we present an efficient margin-based optimization algorithm with a fast computation to make the inference of the information diffusion in the latent embedding space. When applying our proposed method to several social network datasets, the experimental results show the effectiveness of our proposed approach for the information diffusion prediction and the efficiency with respect to the inference speed compared with the state-of-the-art methods. Auteurs: Sheng Gao;Huacan Pang;Patrick Gallinari;Jun Guo;Nei Kato; Apparue dans: IEEE Transactions on Industrial Informatics Date publication: 08.-2017, volume: 13, issue:4, pages: 2097 - 2105 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Framework to Estimate the Path Delay Variability On the Back of an Envelope via the Fan-Out-of-4 Metric
 Résumé:In this paper, a novel framework is introduced to estimate the max-delay variability in logic paths due to variations in a back-of-the-envelope fashion, thus allowing quick evaluation of the additional cycle time margin imposed by random (local) variations. The framework provides the designer with a deep insight into the main variability contributions, and the improvements allowed by prospective design modifications (e.g., logic restructuring and cell up-sizing). The proposed framework is applicable to a wide voltage range, from sub-threshold to nominal. Our analysis shows that the popular fan-out-of-4 metric (FO4) fully captures the impact of technology, supply voltage, die-to-die, and voltage and temperature variations on the delay variability. On the other hand, the variability contribution due to random variations is accounted for by cell-specific coefficients having a clear physical meaning, and depending only on circuit-level parameters knobs (i.e., cell topology and transistor size). Accordingly, the proposed method completely decouples the effect of random variations from the impact of the process/voltage/temperature corner. The proposed approach has been validated in a range of technology generations (28, 40, and 65 nm) and voltages (from 0.3 to 1.2 V) through Monte Carlo simulations and silicon measurements (28 and 65 nm). Being adequately accurate compared with Monte Carlo simulations and silicon measurements, this framework eliminates time-consuming Monte Carlo simulations from the design loop, thus drastically facilitating design closure. Being its accuracy comparable to other state-of-the-art methods, the proposed framework can also be used for efficient automated statistical timing analysis of VLSI circuits. Auteurs: Massimo Alioto;Giuseppe Scotti;Alessandro Trifiletti; Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers Date publication: 08.-2017, volume: 64, issue:8, pages: 2073 - 2085 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel High-Performance Energy Harvester Based on Nonlinear Resonance for Scavenging Power-Frequency Magnetic Energy
 Résumé:Self-powered wireless sensor networks based on autonomous wireless sensor nodes have been increasingly attractive due to the outstanding merits of maintenance-free and self-sustainability. In spite of the explosive growth of the wireless sensor network techniques, the corresponding power supply methods with miniaturized, low-cost, flexible, reliable, and efficient designs are still limited. In this paper, a novel magnetic energy harvester based on nonlinear resonance is presented, which has been verified to be capable of scavenging energy from the power-frequency (50 or 60 Hz) magnetic field distributed around the transmission line. We have theoretically and experimentally demonstrated the greatly enhanced harvesting properties in both power density and enlarged bandwidth, which provides great robustness to frequency fluctuations of magnetic field. A prototype of this brand new design is fabricated and tested. Experimental results show that the prototype is capable of harvesting a power as high as 13.5 mW at merely 2.4 Oe (RMS) power-frequency AC magnetic field. The high power density (0.5625 mW/cm3 at 2.4 Oe) and the wide working bandwidth (2.6 Hz) promise its application prospects as a sufficient and reliable power supply for sensors in the smart grid. Auteurs: Zhongxu Wang;Jun Hu;Jinchi Han;Gen Zhao;Jinliang He;Shan X. Wang; Apparue dans: IEEE Transactions on Industrial Electronics Date publication: 08.-2017, volume: 64, issue:8, pages: 6556 - 6564 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Method of Cone Beam CT Projection Binning Based on Image Registration
 Résumé:Accurate sorting of beam projections is important in 4D cone beam computed tomography (4D CBCT) to improve the quality of the reconstructed 4D CBCT image by removing motion-induced artifacts. We propose image registration-based projection binning (IRPB), a novel marker-less binning method for 4D CBCT projections, which combines intensity-based feature point detection and trajectory tracking using random sample consensus. IRPB extracts breathing motion and phases by analyzing tissue feature point trajectories. We conducted experiments with two phantom and six patient datasets, including both regular and irregular respirations. In experiments, we compared the performance of the proposed IRPB, Amsterdam Shroud method (AS), Fourier transform-based method (FT), and local intensity feature tracking method (LIFT). The results showed that the average absolute phase shift of IRPB was 3.74 projections and 0.48 projections less than that of FT and LIFT, respectively. AS lost the most breathing cycles in the respiration extraction for the five patient datasets, so we could not compare the average absolute phase shift between IRPB and AS. Based on the peak signal-to-noise ratio (PSNR) of the reconstructed 4D CBCT images, IRPB had 5.08, 1.05, and 2.90 dB larger PSNR than AS, FT, and LIFT, respectively. The average Structure SIMilarity Index (SSIM) of the 4D CBCT image reconstructed by IRPB, AS, and LIFT were 0.87, 0.74, 0.84, and 0.70, respectively. These results demonstrated that IRPB has superior performance to the other standard methods. Auteurs: Seonyeong Park;Siyong Kim;Byongyong Yi;Geoffrey Hugo;H. Michael Gach;Yuichi Motai; Apparue dans: IEEE Transactions on Medical Imaging Date publication: 08.-2017, volume: 36, issue:8, pages: 1733 - 1745 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel Multiple Kernel Learning Framework for Multiple Feature Classification
 Résumé:Multiple Kernel Learning (MKL) algorithms have recently demonstrated their effectiveness for classifying the data with numerous features. These algorithms aim at learning an optimal composite kernel through combining the basis kernels constructed from different features. Despite their satisfactory results, MKL algorithms assume that the basis kernels are a priori computed. Moreover, they adopt complex optimization methods to train the combination of the basis kernels, which are usually hard to solve and can only handle the binary classification problems. In this paper, a novel MKL framework was introduced in order to address all these issues. This framework optimizes a data-dependent kernel evaluation measure in order to learn both the basis kernels and their combination. The kernel evaluation measure should be able to estimate the goodness of the composite kernel for a multiclass classification problem. In this paper, we defined such a measure based on the similarity between the composite kernel and an ideal kernel. To this end, three different kernel-based similarity measures, namely kernel alignment (KA), centered kernel alignment (CKA), and Hilbert-Schmidt independence criterion (HSIC), were presented. For solving the optimization problem of the proposed MKL framework, we used the metaheuristic optimization algorithms, which in addition to being accurate algorithms can be easily implemented. The performance of the proposed framework was evaluated by classifying the features extracted from two multispectral and hyperspectral datasets. The results showed that this framework outperformed the other state-of-the-art MKL algorithms in terms of both classification accuracy and the computational time. Auteurs: Saeid Niazmardi;Abdolreza Safari;Saeid Homayouni; Apparue dans: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Date publication: 08.-2017, volume: 10, issue:8, pages: 3734 - 3743 Editeur: IEEE Document complet vers site de l'éditeur
» A Novel PET-Based Piezoresistive MEMS Sensor Platform for Agricultural Applications
 Résumé:A simple and cost effective process is demonstrated for fabricating polyethylene terephthalate (PET) cantilever-based sensor platform with piezoresistive transduction. A one step method is developed to coat graphene nanoplatelet piezoresistive layer on to the PET structural layer. The proposed platform can be used for a variety of sensing applications. The novelty of this process is that it does not require any expensive lithography tools or a specialized clean room facility. We report here the fabrication, characterization, and application of this sensor for the detection of soil macronutrients. Ours is the first report demonstrating the use of PET-based microelectromechanical system for agricultural sensing application. [2017-0094] Auteurs: Rajul S. Patkar;Madhuri Vinchurkar;Mamta Ashwin;V. Ramgopal Rao; Apparue dans: Journal of Microelectromechanical Systems Date publication: 08.-2017, volume: 26, issue:4, pages: 746 - 748 Editeur: IEEE Document complet vers site de l'éditeur

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