#### Electrical and Electronics Engineering publications abstract of: 08-2017 sorted by title, page: 0

» $H_2$-Control of Continuous-Time Hidden Markov Jump Linear Systems
 Abstract:This technical note addresses the -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 guaranteed cost control problem. The technical note is concluded with a numerical example which illustrates the derived results. Autors: F. Stadtmann;O. L. V. Costa; Appeared in: IEEE Transactions on Automatic Control Publication date: Aug 2017, volume: 62, issue:8, pages: 4031 - 4037 Publisher: IEEE
» $K$ -Band Substrate-Integrated Waveguide Filter Using TM21 Mode With Enhanced Stopband Attenuation
 Abstract:In this letter, we present a method for enhancing the stopband attenuation performance of a -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. Autors: Boyoung Lee;Seunggoo Nam;Beyoungyoun Koh;Juseop Lee; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Aug 2017, volume: 27, issue:8, pages: 700 - 702 Publisher: IEEE
» $\mathbb {Z}_{2}\mathbb {Z}_{2}[u]$ –Cyclic and Constacyclic Codes
 Abstract: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. Autors: Ismail Aydogdu;Taher Abualrub;Irfan Siap; Appeared in: IEEE Transactions on Information Theory Publication date: Aug 2017, volume: 63, issue:8, pages: 4883 - 4893 Publisher: IEEE
» $\mathrm {F^{2}}$ Tree: Rapid Failure Recovery for Routing in Production Data Center Networks
 Abstract:Failures are not uncommon in production data center networks (DCNs) nowadays. It takes long time for the DCN routing to recover from a failure and find new forwarding paths, significantly impacting realtime and interactive applications at the upper layer. In this paper, we present a fault-tolerant DCN solution, called Tree, which is readily deployed in existing DNCs. Tree can significantly improve the failure recovery time only through a small amount of link rewiring and switch configuration changes. Through testbed and emulation experiments, we show that Tree can greatly reduce the routing recovery time after failure (by 78%) and improve the performance of upper layer applications when routing failure happens (96% less deadline-missing requests). Autors: Guo Chen;Youjian Zhao;Hailiang Xu;Dan Pei;Dan Li; Appeared in: IEEE/ACM Transactions on Networking Publication date: Aug 2017, volume: 25, issue:4, pages: 1940 - 1953 Publisher: IEEE
» 1.1-kV Vertical GaN p-n Diodes With p-GaN Regrown by Molecular Beam Epitaxy
 Abstract: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. Autors: Zongyang Hu;Kazuki Nomoto;Meng Qi;Wenshen Li;Mingda Zhu;Xiang Gao;Debdeep Jena;Huili Grace Xing; Appeared in: IEEE Electron Device Letters Publication date: Aug 2017, volume: 38, issue:8, pages: 1071 - 1074 Publisher: IEEE
» 2-D Wind Velocity Measurement Using a Vertically Suspended Optical Fiber Combined With a Photosensor Array
 Abstract: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). Autors: Qing-Hao Meng;Pei-Feng Qi;Kai Wu;Shao-Hui Zhu;Ming Zeng; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Aug 2017, volume: 66, issue:8, pages: 2074 - 2082 Publisher: IEEE
» 2017 Outstanding Chapter Awards, New Chapters, and Regional Chapter News [Chapter News]
 Abstract:Presents the recipients of the APS society 2017 Outstanding Chapter Awards as well as recent activiies of new chapters and regional chapter news. Autors: Ajay K. Poddar; Appeared in: IEEE Antennas and Propagation Magazine Publication date: Aug 2017, volume: 59, issue:4, pages: 7 - 75 Publisher: IEEE
» 3-D Frequency-Selective Rasorber With Wide Upper Absorption Band
 Abstract: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. Autors: Yufeng Yu;Zhongxiang Shen;Tianwei Deng;Guoqing Luo; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Aug 2017, volume: 65, issue:8, pages: 4363 - 4367 Publisher: IEEE
» 3-D MIMO: How Much Does It Meet Our Expectations Observed From Channel Measurements?
 Abstract: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 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. Autors: Jianhua Zhang;Yuxiang Zhang;Yawei Yu;Ruijie Xu;Qingfang Zheng;Ping Zhang; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Aug 2017, volume: 35, issue:8, pages: 1887 - 1903 Publisher: IEEE
» 3-D Nonlinear Acoustic Inverse Scattering: Algorithm and Quantitative Results
 Abstract: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. Autors: J. W. Wiskin;D. T. Borup;E. Iuanow;J. Klock;Mark W. Lenox; Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Publication date: Aug 2017, volume: 64, issue:8, pages: 1161 - 1174 Publisher: IEEE
» 4-D Reconstruction With Respiratory Correction for Gated Myocardial Perfusion SPECT
 Abstract: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. Autors: Wenyuan Qi;Yongyi Yang;Chao Song;Miles N. Wernick;P. Hendrik Pretorius;Michael A. King; Appeared in: IEEE Transactions on Medical Imaging Publication date: Aug 2017, volume: 36, issue:8, pages: 1626 - 1635 Publisher: IEEE
» 94-GHz Compact 2-D Multibeam LTCC Antenna Based on Multifolded SIW Beam-Forming Network
 Abstract: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 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. Autors: Wanchen Yang;Yayang Yang;Wenquan Che;Chong Fan;Quan Xue; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Aug 2017, volume: 65, issue:8, pages: 4328 - 4333 Publisher: IEEE
» π Model AC–AC Converter With Controllable Phase and Amplitude
 Abstract: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. Autors: Youjun Zhang;Xinbo Ruan; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Aug 2017, volume: 64, issue:8, pages: 6422 - 6431 Publisher: IEEE
» In Situ Growth of Al2O3 as a Passivation and Antireflection Layer on TiO2-Based MSM Photodetectors
 Abstract: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 – characteristics after the PDs are exposed to air for 30 days. The device with the Al2O3 passivation layer showed the most stable – characteristics and the highest detectivity and the shortest response time among the three devices. Autors: Han-Yin Liu;Guan-Jyun Liu;Ruei-Chin Huang;Wen-Ching Sun;Sung-Yen Wei;Sheng-Min Yu; Appeared in: IEEE Sensors Journal Publication date: Aug 2017, volume: 17, issue:16, pages: 5087 - 5092 Publisher: IEEE
» T-Chain: A General Incentive Scheme for Cooperative Computing
 Abstract:In this paper, we propose a simple, distributed, but highly efficient fairness-enforcing incentive mechanism for cooperative computing. The proposed mechanism, called triangle chaining (T-Chain), enforces reciprocity to avoid the exploitable aspects of the schemes that allow free-riding. In T-Chain, symmetric key cryptography provides the basis for a lightweight, almost-fair exchange protocol, which is coupled with a pay-it-forward mechanism. This combination increases the opportunity for multi-lateral exchanges and further maximizes the resource utilization of participants, each of whom is assumed to operate solely for his or her own benefit. T-Chain also provides barrier-free entry to newcomers with flexible resource allocation, allowing them to immediately benefit, and, therefore, is suitable for dynamic environments with high churn (i.e., turnover). T-Chain is distributed and simple to implement, as no trusted third party is required to monitor or enforce the scheme, nor is there any reliance on reputation information or tokens. Autors: Kyuyong Shin;Carlee Joe-Wong;Sangtae Ha;Yung Yi;Injong Rhee;Douglas S. Reeves; Appeared in: IEEE/ACM Transactions on Networking Publication date: Aug 2017, volume: 25, issue:4, pages: 2122 - 2137 Publisher: IEEE
» ATOM: Efficient Tracking, Monitoring, and Orchestration of Cloud Resources
 Abstract: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. Autors: Min Du;Feifei Li; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Aug 2017, volume: 28, issue:8, pages: 2172 - 2189 Publisher: IEEE
» A 0.038-mm2 SAW-Less Multiband Transceiver Using an N-Path SC Gain Loop
 Abstract: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 I/Q modulation PA driver) and receiver (RX: LNA I/Q demodulation 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 smaller than the state-of-the-art LTE solutions. Autors: Gengzhen Qi;Pui-In Mak;Rui P. Martins; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Aug 2017, volume: 52, issue:8, pages: 2055 - 2070 Publisher: IEEE
» A 0.9–5.8-GHz Software-Defined Receiver RF Front-End With Transformer-Based Current-Gain Boosting and Harmonic Rejection Calibration
 Abstract: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. Autors: Liang Wu;Alan W. L. Ng;Shiyuan Zheng;Hiu Fai Leung;Yue Chao;Alvin Li;Howard C. Luong; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Aug 2017, volume: 25, issue:8, pages: 2371 - 2382 Publisher: IEEE
» A 1-Persistent Based Spectrum Sensing Among the Stochastic Cooperative Users in the Presence of the State-Variable Primary User
 Abstract:The quality of energy detector is quite challenging when the system parameters are not stable. On the other hand, in a cognitive radio network, primary users are licensed to use the desired radio spectrum band(s) and the throughput of the primary network has the highest priority to be kept satisfied. Therefore, it is quite important to secure the quality of primary service to a certain level, and it is worthless to blindly improve the throughput of the secondary network without taking its possible effects on the primary throughput into account. Hence, the mentioned issues motivate us to enhance the total throughput of the system when it suffers from an unstable primary network, due to a medium-traffic rate, and a random density of the secondary users, due to a stochastic-modeled secondary network, at the same time. By introducing a 1-persistent method in a cooperative spectrum sensing scheme, we show how effectively it can improve both primary and secondary throughputs, resulting in higher total throughput of the system. Autors: Ramtin Rabiee;Kwok Hung Li; Appeared in: IEEE Transactions on Wireless Communications Publication date: Aug 2017, volume: 16, issue:8, pages: 5284 - 5295 Publisher: IEEE
» A 140-mV Variation-Tolerant Deep Sub-Threshold SRAM in 65-nm CMOS
 Abstract: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. Autors: Khawar Sarfraz;Jin He;Mansun Chan; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Aug 2017, volume: 52, issue:8, pages: 2215 - 2220 Publisher: IEEE
» A 152-GHz OOK Transmitter With 3-dBm Output Power in 65-nm CMOS
 Abstract: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 . Autors: Xiangyu Meng;Baoyong Chi;Zhihua Wang; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Aug 2017, volume: 27, issue:8, pages: 748 - 750 Publisher: IEEE
» A 160-GHz Radar With Flexible Antenna Used as a Sniffer Probe
 Abstract: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. Autors: Martin Geiger;Martin Hitzler;Stefan Saulig;Johannes Iberle;Philipp Hügler;Christian Waldschmidt; Appeared in: IEEE Sensors Journal Publication date: Aug 2017, volume: 17, issue:16, pages: 5104 - 5111 Publisher: IEEE
» A 190-GHz VCO With 20.7% Tuning Range Employing an Active Mode Switching Block in a 130 nm SiGe BiCMOS
 Abstract: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. Autors: Rouzbeh Kananizadeh;Omeed Momeni; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Aug 2017, volume: 52, issue:8, pages: 2094 - 2104 Publisher: IEEE
» 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
 Abstract: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 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 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 . 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 apart shows ±90° beam steering off broadside. Autors: Imon Mondal;Nagendra Krishnapura; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Aug 2017, volume: 52, issue:8, pages: 2180 - 2193 Publisher: IEEE
» A 2.4-GHz 6.4-mW Fractional-N Inductorless RF Synthesizer
 Abstract:A cascaded synthesizer architecture incorporates a digital delay-line-based filter and an analog noise trap to suppress the quantization noise of the 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. Autors: Long Kong;Behzad Razavi; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Aug 2017, volume: 52, issue:8, pages: 2117 - 2127 Publisher: IEEE
» A 2.4-GHz High Conversion Gain Passive Mixer Using $Q$ -Boosted $\pi$ -Type LCL Matching Networks in 90-nm CMOS
 Abstract: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 -factor by the LC resonance of the -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. Autors: Hyun-Myung Oh;Jae-Sun Kim;Jeong-Taek Lim;Choul-Young Kim; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Aug 2017, volume: 27, issue:8, pages: 736 - 738 Publisher: IEEE
» A 25 GS/s 6b TI Two-Stage Multi-Bit Search ADC With Soft-Decision Selection Algorithm in 65 nm CMOS
 Abstract: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 metastability error rate demonstrates the effectiveness of the soft-decision selection algorithm. Autors: Shengchang Cai;Ehsan Zhian Tabasy;Ayman Shafik;Shiva Kiran;Sebastian Hoyos;Samuel Palermo; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Aug 2017, volume: 52, issue:8, pages: 2168 - 2179 Publisher: IEEE
» A 29.5 dBm Class-E Outphasing RF Power Amplifier With Efficiency and Output Power Enhancement Circuits in 45nm CMOS
 Abstract: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. Autors: Aritra Banerjee;Rahmi Hezar;Lei Ding;Baher Haroun; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Aug 2017, volume: 64, issue:8, pages: 1977 - 1988 Publisher: IEEE
» A 32 $\times$ 32 ISFET Chemical Sensing Array With Integrated Trapped Charge and Gain Compensation
 Abstract:This paper presents a CMOS-based ion-sensitive field-effect transistor (ISFET) system-on-chip for real-time ion imaging. Fabricated in an unmodified 0.35- 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. Autors: Yuanqi Hu;Nicolas Moser;Pantelis Georgiou; Appeared in: IEEE Sensors Journal Publication date: Aug 2017, volume: 17, issue:16, pages: 5276 - 5284 Publisher: IEEE
» A 35-dBm OIP3 CMOS Constant Bandwidth PGA With Extended Input Range and Improved Common-Mode Rejection
 Abstract: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- 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 terminal parasitic capacitance. Autors: Chunfeng Bai;Jianhui Wu;Chao Chen;Xiaoying Deng; Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs Publication date: Aug 2017, volume: 64, issue:8, pages: 922 - 926 Publisher: IEEE
» A 4-M Pixel High Dynamic Range, Low-Noise CMOS Image Sensor With Low-Power Counting ADC
 Abstract: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. Autors: Cheng Ma;Yang Liu;Yang Li;Quan Zhou;Xinyang Wang;Yuchun Chang; Appeared in: IEEE Transactions on Electron Devices Publication date: Aug 2017, volume: 64, issue:8, pages: 3199 - 3205 Publisher: IEEE
» A 50-mA 99.2% Peak Current Efficiency, 250-ns Settling Time Digital Low-Dropout Regulator With Transient Enhanced PI Controller
 Abstract: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- CMOS technology and occupies a 0.0631-mm2 die area. Autors: ChaiYong Lim;Debashis Mandal;Bertan Bakkaloglu;Sayfe Kiaei; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Aug 2017, volume: 25, issue:8, pages: 2360 - 2370 Publisher: IEEE
» A 60-GHz Coplanar Waveguide-Based Bidirectional LNA in SiGe BiCMOS
 Abstract: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- 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. Autors: Thangarasu Bharatha Kumar;Kaixue Ma;Kiat Seng Yeo; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Aug 2017, volume: 27, issue:8, pages: 742 - 744 Publisher: IEEE
» A 7.8-mW 5-b 5-GS/s Dual-Edges-Triggered Time-Based Flash ADC
 Abstract: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. Autors: Chi-Hang Chan;Yan Zhu;Sai-Weng Sin;U. Seng-Pan;Rui P. Martins;Franco Maloberti; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Aug 2017, volume: 64, issue:8, pages: 1966 - 1976 Publisher: IEEE
» A Backprojection-Based Imaging for Circular Synthetic Aperture Radar
 Abstract: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. Autors: Leping Chen;Daoxiang An;Xiaotao Huang; Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Publication date: Aug 2017, volume: 10, issue:8, pages: 3547 - 3555 Publisher: IEEE
» A Backstepping Approach to Decentralized Active Disturbance Rejection Control of Interacting Boost Converters
 Abstract: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. Autors: Arturo Hernández-Méndez;Jesús Linares-Flores;Hebertt Sira-Ramírez;Jóse F. Guerrero-Castellanos;Gerardo Mino-Aguilar; Appeared in: IEEE Transactions on Industry Applications Publication date: Aug 2017, volume: 53, issue:4, pages: 4063 - 4072 Publisher: IEEE
» A BCI-Based Environmental Control System for Patients With Severe Spinal Cord Injuries
 Abstract: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. Autors: 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; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Aug 2017, volume: 64, issue:8, pages: 1959 - 1971 Publisher: IEEE
» A Billion-Scale Approximation Algorithm for Maximizing Benefit in Viral Marketing
 Abstract:Online social networks have been one of the most effective platforms for marketing and advertising. Through the “world-of-mouth” exchanges, so-called viral marketing, the influence and product adoption can spread from few key influencers to billions of users in the network. To identify those key influencers, a great amount of work has been devoted for the influence maximization (IM) problem that seeks a set of seed users that maximize the expected influence. Unfortunately, IM encloses two impractical assumptions: 1) any seed user can be acquired with the same cost and 2) all users are equally interested in the advertisement. In this paper, we propose a new problem, called cost-aware targeted viral marketing ( CTVM), to find the most cost-effective seed users, who can influence the most relevant users to the advertisement. Since CTVM is NP-hard, we design an efficient -approximation algorithm, named Billion-scale Cost-award Targeted algorithm (BCT), to solve the problem in billion-scale networks. Comparing with IM algorithms, we show that BCT is both theoretically and experimentally faster than the state-of-the-arts while providing better solution quality. Moreover, we prove that under the linear threshold model, BCT is the first sub-linear time algorithm for CTVM (and IM) in dense networks. We carry a comprehensive set of experiments on various real-networks with sizes up to several billion edges in diverse disciplines to show the absolute superiority of BCT on both CTVM and IM domains. Experiments on Twitter data set- containing 1.46 billions of social relations and 106 millions tweets, show that BCT can identify key influencers in trending topics in only few minutes. Autors: Hung T. Nguyen;My T. Thai;Thang N. Dinh; Appeared in: IEEE/ACM Transactions on Networking Publication date: Aug 2017, volume: 25, issue:4, pages: 2419 - 2429 Publisher: IEEE
» A Biquadratic Cell Based on the Flipped-Source-Follower Circuit
 Abstract: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 . Input noise spectral density is 7 nV/vHz. Linearity has been evaluated in terms of IIP3 (25 dBm) and THD (−40 dBc at 380 output voltage swing, resulting in 62-dB SNR). Hence, a very promising figure-of-merit (i.e., 165 ) has been achieved. Autors: Marcello De Matteis;Andrea Baschirotto; Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs Publication date: Aug 2017, volume: 64, issue:8, pages: 867 - 871 Publisher: IEEE
» A Broad Range of Speed Control of a Permanent Magnet Synchronous Motor Driven by a Modular Multilevel TSBC Converter
 Abstract: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. Autors: Wataru Kawamura;Yuto Chiba;Hirofumi Akagi; Appeared in: IEEE Transactions on Industry Applications Publication date: Aug 2017, volume: 53, issue:4, pages: 3821 - 3830 Publisher: IEEE
» A Broadband High-Efficiency Reconfigurable Reflectarray Antenna Using Mechanically Rotational Elements
 Abstract: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 manually rotated elements is first computed, simulated, and measured. Full-wave simulations show that the gain of the beam focused in (, ) direction is 25.8 dB and the 1-dB gain bandwidth is over 28.6%. The measured results show that the beam at (, ) 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. Autors: Xue Yang;Shenheng Xu;Fan Yang;Maokun Li;Yangqing Hou;Shuidong Jiang;Lei Liu; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Aug 2017, volume: 65, issue:8, pages: 3959 - 3966 Publisher: IEEE
» A Calculation Framework for Quantifying the Probability of Ventricular Fibrillation of Rare Events
 Abstract: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. Autors: Ian Griffiths;Darren J. Woodhouse; Appeared in: IEEE Transactions on Power Delivery Publication date: Aug 2017, volume: 32, issue:4, pages: 2052 - 2059 Publisher: IEEE
» A Capacitated Vehicle Routing Problem With Synchronized Pick-Ups and Drop-Offs: The Case of Medication Delivery and Supervision in the DR Congo
 Abstract: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. Autors: John Clarke;Viviane Gascon;Jacques A. Ferland; Appeared in: IEEE Transactions on Engineering Management Publication date: Aug 2017, volume: 64, issue:3, pages: 327 - 336 Publisher: IEEE
» A Circularly Polarized High-Gain Antenna With Low RCS Over a Wideband Using Chessboard Polarization Conversion Metasurfaces
 Abstract: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 -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. Autors: Kun Li;Ying Liu;Yongtao Jia;Y. J. Guo; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Aug 2017, volume: 65, issue:8, pages: 4288 - 4292 Publisher: IEEE
» A Circulating-Current Suppression Method for Parallel-Connected Voltage-Source Inverters With Common DC and AC Buses
 Abstract: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. Autors: Baoze Wei;Josep M. Guerrero;Juan C. Vásquez;Xiaoqiang Guo; Appeared in: IEEE Transactions on Industry Applications Publication date: Aug 2017, volume: 53, issue:4, pages: 3758 - 3769 Publisher: IEEE
» A Closed-Form Solution for the Low-Current Collector Transit Time in Group IV and Group III-V HBTs
 Abstract: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. Autors: Michael Schröter;Tobias Nardmann;Gerald Wedel; Appeared in: IEEE Transactions on Electron Devices Publication date: Aug 2017, volume: 64, issue:8, pages: 3346 - 3352 Publisher: IEEE
» A Coding Theorem for Bipartite Unitaries in Distributed Quantum Computation
 Abstract: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 , where 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. Autors: Eyuri Wakakuwa;Akihito Soeda;Mio Murao; Appeared in: IEEE Transactions on Information Theory Publication date: Aug 2017, volume: 63, issue:8, pages: 5372 - 5403 Publisher: IEEE
 Abstract:To deal with the problems of range cell migration (RCM) and spectrum spread during the integration time induced by the motion of a target, this paper proposes a new coherent integration method based on Radon nonuniform fractional Fourier transform (NUFrFT) for random pulse repetition interval radar. In this method, RCM is eliminated via searching in the motion parameter space and the spectrum spread is resolved by NUFrFT along the searching trajectory. Simulation results demonstrate the effectiveness of the proposed algorithm. Autors: Jing Tian;Xiang-Gen Xia;Wei Cui;Gang Yang;Si-Liang Wu; Appeared in: IEEE Transactions on Aerospace and Electronic Systems Publication date: Aug 2017, volume: 53, issue:4, pages: 2101 - 2109 Publisher: IEEE
» A Common Transceiver Design for Nonregenerative Asymmetric and Symmetric Two-Way Relaying With Relaxed Antenna Constraints
 Abstract: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. Autors: Rohit Budhiraja;Ajit K. Chaturvedi; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Aug 2017, volume: 66, issue:8, pages: 7026 - 7037 Publisher: IEEE
» A Compact Memristor-Based Dynamic Synapse for Spiking Neural Networks
 Abstract: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. Autors: Miao Hu;Yiran Chen;J. Joshua Yang;Yu Wang;Hai Helen Li; Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Publication date: Aug 2017, volume: 36, issue:8, pages: 1353 - 1366 Publisher: IEEE
» A Compact Model for the Statistics of the Low-Frequency Noise of MOSFETs With Laterally Uniform Doping
 Abstract: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. Autors: Maurício Banaszeski da Silva;Hans P. Tuinhout;Adrie Zegers-van Duijnhoven;Gilson I. Wirth;Andries J. Scholten; Appeared in: IEEE Transactions on Electron Devices Publication date: Aug 2017, volume: 64, issue:8, pages: 3331 - 3336 Publisher: IEEE
» A Compact Short-Channel Model for Symmetric Double-Gate TMDFET in Subthreshold Region
 Abstract:This paper presents a compact analytical – 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. Autors: Morteza Gholipour; Appeared in: IEEE Transactions on Electron Devices Publication date: Aug 2017, volume: 64, issue:8, pages: 3466 - 3469 Publisher: IEEE
» A Comparative Review of the Methodologies to Identify a Global Earthing System
 Abstract: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. Autors: Pietro Colella;Enrico Pons;Riccardo Tommasini; Appeared in: IEEE Transactions on Industry Applications Publication date: Aug 2017, volume: 53, issue:4, pages: 3260 - 3267 Publisher: IEEE
» A Comparative Study on TID Influenced Lateral Diffusion of Group 11 Metals Into GexS1−x and GexSe1−x Systems: A Flexible Radiation Sensor Development Perspective
 Abstract:The impact of varying: 1) metals used to form contact electrodes and 2) chalcogenide glass atomic ratio/chemical composition on the performance of our recently developed flexible radiation detection sensors has been investigated. For electrodes, three group 11 elements (i.e., copper, silver, and gold) were used. For chalcogenide glass film, either GexS1−x or GexSe1−x was used where the atomic ratio of the chalcogen atoms (i.e., sulfide or selenide) was varied from device to device. Selenide systems with Ag electrodes were found to be very promising, since the limit of detection of the sensors showed clear dependence on the Se atomic ratio in the chalcogenide glass film. The other selenide and sulfide systems with different group 11 metal electrodes were not as suitable for the present lateral diffusion-based design due to either their control instability or very slow diffusion caused by irradiation from a 60Co source. Autors: A. Mahmud;Y. Gonzalez-Velo;H. J. Barnaby;M. N. Kozicki;M. Mitkova;K. E. Holbert;M. Goryll;T. L. Alford;J. L. Taggart;W. Chen; Appeared in: IEEE Transactions on Nuclear Science Publication date: Aug 2017, volume: 64, issue:8, pages: 2292 - 2299 Publisher: IEEE
» A Comparison of Finite Element-Based Inversion Algorithms, Local Frequency Estimation, and Direct Inversion Approach Used in MRE
 Abstract: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. Autors: Mohammad Honarvar;Ramin S. Sahebjavaher;Robert Rohling;Septimiu E. Salcudean; Appeared in: IEEE Transactions on Medical Imaging Publication date: Aug 2017, volume: 36, issue:8, pages: 1686 - 1698 Publisher: IEEE
» A Comprehensive Investigation of a Microfabricated U-Bend Polymer Waveguide With Analyte Micro-Reservoir for Versatile On-Chip Sensing Applications
 Abstract: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] Autors: Amit Prabhakar;Neha Mishra;Soumyo Mukherji; Appeared in: Journal of Microelectromechanical Systems Publication date: Aug 2017, volume: 26, issue:4, pages: 935 - 945 Publisher: IEEE
» A Comprehensive Theoretical Analysis of Hole Ballistic Velocity in Si, SiGe, and Ge: Effect of Uniaxial Strain, Crystallographic Orientation, Body Thickness, and Gate Architecture
 Abstract: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 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 -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 cm/s at #/cm2. Autors: James T. Teherani; Appeared in: IEEE Transactions on Electron Devices Publication date: Aug 2017, volume: 64, issue:8, pages: 3316 - 3323 Publisher: IEEE
» A Controllably Inductive Filtering Method With Transformer-Integrated Linear Reactor for Power Quality Improvement of Shipboard Power System
 Abstract: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. Autors: Yong Li;Yanjian Peng;Fang Liu;Denis Sidorov;Daniil Panasetsky;Chonggan Liang;Longfu Luo;Yijia Cao; Appeared in: IEEE Transactions on Power Delivery Publication date: Aug 2017, volume: 32, issue:4, pages: 1817 - 1827 Publisher: IEEE
» A Coordinated Control Approach for DC link and Rotor Crowbars to Improve Fault Ride-Through of DFIG-Based Wind Turbine
 Abstract: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. Autors: Ahmed M. A. Haidar;Kashem M. Muttaqi;Mehrdad Tarafdar Hagh; Appeared in: IEEE Transactions on Industry Applications Publication date: Aug 2017, volume: 53, issue:4, pages: 4073 - 4086 Publisher: IEEE
» A Correction Formula for the ST-Segment Measurements of AC-Coupled Electrocardiograms
 Abstract: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. Autors: Ramun Schmid;Jonas L. Isaksen;Remo Leber;Hans-Jakob Schmid;Gianluca Generali;Roger Abächerli; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Aug 2017, volume: 64, issue:8, pages: 1834 - 1840 Publisher: IEEE
» A COTS-Based Microwave Imaging System for Breast-Cancer Detection
 Abstract: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. Autors: Mario R. Casu;Marco Vacca;Jorge A. Tobon;Azzurra Pulimeno;Imran Sarwar;Raffaele Solimene;Francesca Vipiana; Appeared in: IEEE Transactions on Biomedical Circuits and Systems Publication date: Aug 2017, volume: 11, issue:4, pages: 804 - 814 Publisher: IEEE
» A Cubature Kalman Filter Based Power System Dynamic State Estimator
 Abstract: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. Autors: A. Sharma;S. C. Srivastava;S. Chakrabarti; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Aug 2017, volume: 66, issue:8, pages: 2036 - 2045 Publisher: IEEE
» A Data-Driven Method for Trip Ends Identification Using Large-Scale Smartphone-Based GPS Tracking Data
 Abstract: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. Autors: Chaoran Zhou;Hongfei Jia;Zhicai Juan;Xuemei Fu;Guangnian Xiao; Appeared in: IEEE Transactions on Intelligent Transportation Systems Publication date: Aug 2017, volume: 18, issue:8, pages: 2096 - 2110 Publisher: IEEE
» A Decoupled Control Strategy of Modular Multilevel Matrix Converter for Fractional Frequency Transmission System
 Abstract: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. Autors: Shenquan Liu;Xifan Wang;Yongqing Meng;Pengwei Sun;Huiyong Luo;Biyang Wang; Appeared in: IEEE Transactions on Power Delivery Publication date: Aug 2017, volume: 32, issue:4, pages: 2111 - 2121 Publisher: IEEE
» A Design of an Origami Reconfigurable QHA with a Foldable Reflector [Antenna Applications Corner]
 Abstract: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. Autors: Xueli Liu;Stavros V. Georgakopoulos;Sudhakar Rao; Appeared in: IEEE Antennas and Propagation Magazine Publication date: Aug 2017, volume: 59, issue:4, pages: 78 - 105 Publisher: IEEE
» A Diagonal Subspace-Based Optimization Method for Reconstruction of 2-D Isotropic and Uniaxial Anisotropic Dielectric Objects
 Abstract: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. Autors: Yulang Liu;Zhiqin Zhao;Xiaozhang Zhu;Wei Yang;Zaiping Nie;Qing-Huo Liu; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Aug 2017, volume: 14, issue:8, pages: 1318 - 1322 Publisher: IEEE
» A Diesel-Powered Fuel Cell APU—Reliability Issues and Mitigation Approaches
 Abstract: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. Autors: Boštjan Pregelj;Andrej Debenjak;Gregor Dolanc;Janko Petrovčič; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Aug 2017, volume: 64, issue:8, pages: 6660 - 6670 Publisher: IEEE
» A Differential Game Approach to Multi-agent Collision Avoidance
 Abstract:A multi-agent system consisting of 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. Autors: Thulasi Mylvaganam;Mario Sassano;Alessandro Astolfi; Appeared in: IEEE Transactions on Automatic Control Publication date: Aug 2017, volume: 62, issue:8, pages: 4229 - 4235 Publisher: IEEE
» A Digital Frequency Adaptive Synchronization Unit for On- and Off-Grid Systems
 Abstract: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. Autors: Essam S. Elsahwi;Adrian Zsombor Amanci;Francis P. Dawson; Appeared in: IEEE Transactions on Power Delivery Publication date: Aug 2017, volume: 32, issue:4, pages: 2070 - 2080 Publisher: IEEE
» A Distance-Based Two-Stage Ecological Driving System Using an Estimation of Distribution Algorithm and Model Predictive Control
 Abstract: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. Autors: Hansang Lim;Chunting Chris Mi;Wencong Su; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Aug 2017, volume: 66, issue:8, pages: 6663 - 6675 Publisher: IEEE
» A Distributed Parallel Cooperative Coevolutionary Multiobjective Evolutionary Algorithm for Large-Scale Optimization
 Abstract: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. Autors: Bin Cao;Jianwei Zhao;Zhihan Lv;Xin Liu; Appeared in: IEEE Transactions on Industrial Informatics Publication date: Aug 2017, volume: 13, issue:4, pages: 2030 - 2038 Publisher: IEEE
» A Distributed Version of the Hungarian Method for Multirobot Assignment
 Abstract: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. Autors: Smriti Chopra;Giuseppe Notarstefano;Matthew Rice;Magnus Egerstedt; Appeared in: IEEE Transactions on Robotics Publication date: Aug 2017, volume: 33, issue:4, pages: 932 - 947 Publisher: IEEE
» A Dual-Channel MEMS Amplitude Demodulator for On-Line Detection in Radio Relay Station
 Abstract: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. Autors: Hao Yan;Xiaoping Liao;Chenglin Li; Appeared in: IEEE Electron Device Letters Publication date: Aug 2017, volume: 38, issue:8, pages: 1121 - 1124 Publisher: IEEE
» A Dual-Polarized Dual-Band Antenna With Omni-Directional Radiation Patterns
 Abstract: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 - and -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 (, where is the wavelength in free space). The antenna has a low profile of 4 mm (). 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. Autors: Yi Liu;Xi Li;Lin Yang;Ying Liu; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Aug 2017, volume: 65, issue:8, pages: 4259 - 4262 Publisher: IEEE
» A Dynamic Topic Model and Matrix Factorization-Based Travel Recommendation Method Exploiting Ubiquitous Data
 Abstract: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. Autors: Zhenxing Xu;Ling Chen;Yimeng Dai;Gencai Chen; Appeared in: IEEE Transactions on Multimedia Publication date: Aug 2017, volume: 19, issue:8, pages: 1933 - 1945 Publisher: IEEE
» A Dynamic Wireless Power Transfer System Applicable to a Stationary System
 Abstract: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. Autors: Toshiyuki Fujita;Tomio Yasuda;Hirofumi Akagi; Appeared in: IEEE Transactions on Industry Applications Publication date: Aug 2017, volume: 53, issue:4, pages: 3748 - 3757 Publisher: IEEE
» A Family of Zero-Voltage-Switching Magnetic Coupling Nonisolated Bidirectional DC–DC Converters
 Abstract: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. Autors: Guipeng Chen;Yan Deng;Luan Chen;Yihua Hu;Lin Jiang;Xiangning He;Yousheng Wang; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Aug 2017, volume: 64, issue:8, pages: 6223 - 6233 Publisher: IEEE
» A Fast Density and Grid Based Clustering Method for Data With Arbitrary Shapes and Noise
 Abstract: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. Autors: Bo Wu;Bogdan M. Wilamowski; Appeared in: IEEE Transactions on Industrial Informatics Publication date: Aug 2017, volume: 13, issue:4, pages: 1620 - 1628 Publisher: IEEE
» A Fast Edge Extraction Method for Mobile Lidar Point Clouds
 Abstract: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. Autors: Shaobo Xia;Ruisheng Wang; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Aug 2017, volume: 14, issue:8, pages: 1288 - 1292 Publisher: IEEE
» A Fiber-Optic Mechanoreceptor in a Finger-Shaped End Effector for Human-Like Tactile Sensing
 Abstract: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. Autors: Hiroshi Yamazaki;Michiko Nishiyama;Kazuhiro Watanabe; Appeared in: IEEE Sensors Journal Publication date: Aug 2017, volume: 17, issue:16, pages: 5123 - 5129 Publisher: IEEE
» A Fitting Model for Feature Selection With Fuzzy Rough Sets
 Abstract: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. Autors: Changzhong Wang;Yali Qi;Mingwen Shao;Qinghua Hu;Degang Chen;Yuhua Qian;Yaojin Lin; Appeared in: IEEE Transactions on Fuzzy Systems Publication date: Aug 2017, volume: 25, issue:4, pages: 741 - 753 Publisher: IEEE
» A Fixed-Lag Kalman Smoother to Filter Power Line Interference in Electrocardiogram Recordings
 Abstract: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. Autors: G. J. J. Warmerdam;R. Vullings;L. Schmitt;J. O. E. H. Van Laar;J. W. M. Bergmans; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Aug 2017, volume: 64, issue:8, pages: 1852 - 1861 Publisher: IEEE
» A Formal Methodology for Accomplishing IEC 61850 Real-Time Communication Requirements
 Abstract: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. Autors: Guilherme Kunz;José Machado;Eduardo Perondi;Valeriy Vyatkin; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Aug 2017, volume: 64, issue:8, pages: 6582 - 6590 Publisher: IEEE
» A fourth category of software-defined instrumentation for wireless test
 Abstract:The increasing demand for wireless data services is driving the development of wideband radio technologies and products. Technologies such as 802.11ac that utilize up to 160 MHz of bandwidth are on the market today, and 5G is expected to use up to 2 GHz to support bandwidth intensive applications. The test and measurement of such devices requires modern analysis equipment with stringent specifications. Furthermore, shrinking test equipment budgets necessitate newer, more creative and cost-effective approaches to testing devices. While software-defined radio (SDR) approaches to instrumentation have been on the market for many years, their price points have typically been high. Autors: Tarek Helaly;Nikhil Adnani; Appeared in: IEEE Instrumentation & Measurement Magazine Publication date: Aug 2017, volume: 20, issue:4, pages: 3 - 10 Publisher: IEEE
» A Frequency-Sweeping Framework for Stability Analysis of Time-Delay Systems
 Abstract: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. Autors: Xu-Guang Li;Silviu-Iulian Niculescu;Arben Çela;Lu Zhang;Xu Li; Appeared in: IEEE Transactions on Automatic Control Publication date: Aug 2017, volume: 62, issue:8, pages: 3701 - 3716 Publisher: IEEE
» A Fully Passive Compressive Sensing SAR ADC for Low-Power Wireless Sensors
 Abstract: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- CMOS process. At 0.8 V and 1 MS/s, the chip consumes 19.2 in the Nyquist mode and 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. Autors: Wenjuan Guo;Youngchun Kim;Ahmed H. Tewfik;Nan Sun; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Aug 2017, volume: 52, issue:8, pages: 2154 - 2167 Publisher: IEEE
» A Fuzzy Approach Based on Heterogeneous Metrics for Scaling Out Public Clouds
 Abstract: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. Autors: Valerio Persico;Domenico Grimaldi;Antonio Pescapè;Alessandro Salvi;Stefania Santini; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Aug 2017, volume: 28, issue:8, pages: 2117 - 2130 Publisher: IEEE
» A Gaussian Sum Method to Analyze Bounded Acceleration Guidance Systems
 Abstract:To analyze a highly nonlinear dynamical system, it is necessary to evaluate the time evolution of the probability density function (pdf) of the states. In this paper, a novel Gaussian sum method is proposed to approximate the non-Gaussian pdf of a dynamical system whose nonlinear elements depend only on a single state variable. Using the Chapman–Kolmogorov equation, a set of recursive equations is derived to propagate the mean, covariance, and weight of the Gaussian sum components. There are several multiple integrals in the recursive equations which are analytically reduced to single integrals. As an application, the proposed approach is applied to statistically analyze the engagement of two pursuers with bounded acceleration against a randomly step evader maneuver. Pursuers are assumed to use the zero-lag version of the recently developed optimal cooperative guidance law (OCGL) or the well-known proportional navigation (PN). The results show that the accuracy of the proposed method is equivalent to Monte Carlo simulation which requires extensive computational effort. Utilizing the proposed analytical Gaussian sum method, OCGL and PN are statistically investigated and compared with each other. The results demonstrate that OCGL is superior to PN, especially when the guidance system is highly in saturation. Autors: Mahdi Nikusokhan;Hadi Nobahari; Appeared in: IEEE Transactions on Aerospace and Electronic Systems Publication date: Aug 2017, volume: 53, issue:4, pages: 2060 - 2076 Publisher: IEEE
» A General and Transformable Model Platform for Emerging Multi-Gate MOSFETs
 Abstract: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. Autors: Chuyang Hong;Jun Zhou;Jiasheng Huang;Rui Wang;Wenlong Bai;James B. Kuo;Yijian Chen; Appeared in: IEEE Electron Device Letters Publication date: Aug 2017, volume: 38, issue:8, pages: 1015 - 1018 Publisher: IEEE
» A Generalized Lattice Based Probabilistic Approach for Metagenomic Clustering
 Abstract:Metagenomics involves the analysis of genomes of microorganisms sampled directly from their environment. Next Generation Sequencing allows a high-throughput sampling of small segments from genomes in the metagenome to generate reads. To study the properties and relationships of the microorganisms present, clustering can be performed based on the inherent composition of the sampled reads for unknown species. We propose a two-dimensional lattice based probabilistic model for clustering metagenomic datasets. The occurrence of a species in the metagenome is estimated using a lattice of probabilistic distributions over small sized genomic sequences. The two dimensions denote distributions for different sizes and groups of words, respectively. The lattice structure allows for additional support for a node from its neighbors when the probabilistic support for the species using the parameters of the current node is deemed insufficient. We also show convergence for our algorithm. We test our algorithm on simulated metagenomic data containing bacterial species and observe more than precision. We also evaluate our algorithm on an in vitro-simulated bacterial metagenome and on human patient data, and show a better clustering than other algorithms even for short reads and varied abundance. The software and datasets can be downloaded from https:// github.com/lattclus/lattice-metage . Autors: Manjari Jha;Raunaq Malhotra;Raj Acharya; Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics Publication date: Aug 2017, volume: 14, issue:4, pages: 749 - 761 Publisher: IEEE
» A Gridless Approach to the Satisfiability of Self-Aligned Triple Patterning
 Abstract: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. Autors: Hsiao-Lei Chien;Mei-Yen Chiu;Jie-Hong R. Jiang; Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems Publication date: Aug 2017, volume: 36, issue:8, pages: 1251 - 1264 Publisher: IEEE
» A Hardware-Efficient Scalable Spike Sorting Neural Signal Processor Module for Implantable High-Channel-Count Brain Machine Interfaces
 Abstract: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. Autors: Yuning Yang;Sam Boling;Andrew J. Mason; Appeared in: IEEE Transactions on Biomedical Circuits and Systems Publication date: Aug 2017, volume: 11, issue:4, pages: 743 - 754 Publisher: IEEE
» A Hierarchical Data Transmission Framework for Industrial Wireless Sensor and Actuator Networks
 Abstract: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 relative to existing methods. Autors: Xi Jin;Fanxin Kong;Linghe Kong;Huihui Wang;Changqing Xia;Peng Zeng;Qingxu Deng; Appeared in: IEEE Transactions on Industrial Informatics Publication date: Aug 2017, volume: 13, issue:4, pages: 2019 - 2029 Publisher: IEEE

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