#### Electrical and Electronics Engineering publications abstract of: 09-2017 sorted by title, page: 2

» A Spatial and Temporal Locality-Aware Adaptive Cache Design With Network Optimization for Tiled Many-Core Architectures
 Abstract:The spatial locality and the temporal locality of workloads are the root causes for cache designs to overcome the memory wall problem. However, the real memory access behavior for each of these applications can be very different. It gives the opportunities to explore further performance improvement due to different cache organization requirements. To address this issue, a spatial and temporal locality-aware adaptive cache is proposed, which dynamically partitions the private last level cache bank as prefetch region or victim region at runtime to explore the locality characteristics. The prefetch region speculates the data blocks in subsequent addresses to exploit the spatial locality, while the victim region collects the evicted data blocks from the upper memory hierarchy to exploit the temporal locality. Fast data prefetch with prioritized dynamic buffer management and adaptive burst-aware routing is realized in the proposed hybrid burst-support network-on-chip (HBNoC). By combining the adaptive cache partition with HBNoC, the off-chip misses and the on-chip network usage are greatly reduced. Experimental results demonstrate that the proposed adaptive cache design reduces up to 25% off-chip misses and improves 11.3% performance on average compared with the prior design, respectively. Autors: Mingyu Wang;Zhaolin Li; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Sep 2017, volume: 25, issue:9, pages: 2419 - 2433 Publisher: IEEE
» A Spectral CT Method to Directly Estimate Basis Material Maps From Experimental Photon-Counting Data
 Abstract:The proposed spectral CT method solves the constrained one-step spectral CT reconstruction (cOSSCIR) optimization problem to estimate basis material maps while modeling the nonlinear X-ray detection process and enforcing convex constraints on the basis map images. In order to apply the optimization-based reconstruction approach to experimental data, the presented method empirically estimates the effective energy-window spectra using a calibration procedure. The amplitudes of the estimated spectra were further optimized as part of the reconstruction process to reduce ring artifacts. A validation approach was developed to select constraint parameters. The proposed spectral CT method was evaluated through simulations and experiments with a photon-counting detector. Basis material map images were successfully reconstructed using the presented empirical spectral modeling and cOSSCIR optimization approach. In simulations, the cOSSCIR approach accurately reconstructed the basis map images (<1% error). In experiments, the proposed method estimated the low-density polyethylene region of the basis maps with 0.5% error in the PMMA image and 4% error in the aluminum image. For the Teflon region, the experimental results demonstrated 8% and 31% error in the PMMA and aluminum basis material maps, respectively, compared with −24% and 126% error without estimation of the effective energy window spectra, with residual errors likely due to insufficient modeling of detector effects. The cOSSCIR algorithm estimated the material decomposition angle to within 1.3 degree error, where, for reference, the difference in angle between PMMA and muscle tissue is 2.1 degrees. The joint estimation of spectral-response scaling coefficients and basis material maps was found to reduce ring artifacts in both a phantom and tissue sp- cimen. The presented validation procedure demonstrated feasibility for the automated determination of algorithm constraint parameters. Autors: Taly Gilat Schmidt;Rina Foygel Barber;Emil Y. Sidky; Appeared in: IEEE Transactions on Medical Imaging Publication date: Sep 2017, volume: 36, issue:9, pages: 1808 - 1819 Publisher: IEEE
» A Spectral-Efficient Transmission Scheme for Dimmable Visible Light Communication Systems
 Abstract:Dimming control is of vital importance for visible light communication (VLC) systems. Conventional dimmable transmission schemes based on compensation are spectrally inefficient. In this paper, we propose the use of two techniques, i.e., time-sharing and superposition, to construct spectral-efficient dimmable transmission schemes. For VLC systems with on-off keying (OOK) signaling, we present a general framework to construct dimmable transmission scheme by time-sharing among different dimming control codes. Arbitrary dimming target is achieved by adjusting the proportion of each dimming control code. We, then, give a practical construction of dimming control codes with semi-constant weight codes. We obtain optimal proportions of the semi-constant weight codes, which maximize the asymptotic spectral efficiency using linear programming. We also compute achievable rates of the proposed scheme under different dimming targets and different signal-intensity-to-noise-amplitude ratios. To achieve higher spectral efficiency (>1.0 (b/s)/Hz), we present a dimmable multilevel transmission scheme based on superposition. In the proposed scheme, the first ℓ-1 levels adopt traditional OOK modulation, whereas the ℓth level adopts the dimmable transmission scheme for OOK modulation. The transmitted signal is formed by superimposing modulated signals of the ℓ levels. Analysis shows that the proposed scheme achieves a higher spectral efficiency than the state-of-the-art schemes. Hence, it provides an attractive candidate for dimmable VLC systems with demanding spectral efficiency. Autors: Shancheng Zhao;Xiao Ma; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:17, pages: 3801 - 3809 Publisher: IEEE
» A State-Independent Linear Power Flow Model With Accurate Estimation of Voltage Magnitude
 Abstract:Linearized power flow models are of great interest in power system studies such as contingency analyses and reliability assessments, especially for large-scale systems. One of the most popular models—the classical DC power flow model—is widely used and praised for its state independence, robustness, and computational efficiency. Despite its advantages, however, the DC power flow model fails to consider reactive power or bus voltage magnitude. This paper closes this gap by proposing a decoupled linearized power flow (DLPF) model with respect to voltage magnitude and phase angle. The model is state independent but is distinguished by its high accuracy in voltage magnitude. Moreover, this paper presents an in-depth analysis of the DLPF model with the purpose of accelerating its computation speed, leading to the fast DLPF (FDLPF) model. The approximation that is applied to obtain the FDLPF model from the DLPF model is justified by a theoretical derivation and numerical tests. The proposed methods are provably accurate and robust for several cases, including radial distribution systems, meshed large-scale transmission systems and ill-conditioned systems. Finally, expressions for sensitivity with regard to MW flow and bus voltage are provided as a potential application. Autors: Jingwei Yang;Ning Zhang;Chongqing Kang;Qing Xia; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3607 - 3617 Publisher: IEEE
» A Stepwise Analytical Projected Gradient Descent Search for Hyperspectral Unmixing and Its Code Vectorization
 Abstract:We present, in this paper, a new methodology for spectral unmixing, where a vector of fractions, corresponding to a set of endmembers (EMs), is estimated for each pixel in the image. The process first provides an initial estimate of the fraction vector, followed by an iterative procedure that converges to an optimal solution. Specifically, projected gradient descent (PGD) optimization is applied to (a variant of) the spectral angle mapper objective function, so as to significantly reduce the estimation error due to amplitude (i.e., magnitude) variations in EM spectra, caused by the illumination change effect. To improve the computational efficiency of our method over a commonly used gradient descent technique, we have analytically derived the objective function’s gradient and the optimal step size (used in each iteration). To gain further improvement, we have implemented our unmixing module via code vectorization, where the entire process is “folded” into a single loop, and the fractions for all of the pixels are solved simultaneously. We call this new parallel scheme vectorized code PGD unmixing (VPGDU). VPGDU has the advantage of solving (simultaneously) an independent optimization problem per image pixel, exactly as other pixelwise algorithms, but significantly faster. Its performance was compared with the commonly used fully constrained least squares unmixing (FCLSU), the generalized bilinear model (GBM) method for hyperspectral unmixng, and the fast state-of-the-art methods, sparse unmixing by variable splitting and augmented Lagrangian (SUnSAL) and collaborative SUnSAL (CLSUnSAL) based on the alternating direction method of multipliers. Considering all of the prospective EMs of a scene at each pixel (i.e., without a priori knowledge which/how many EMs are actually present in a given pixel), we demonstrate that the accuracy due to VPGDU is considerably higher than that obtained by FCLSU, GBM, SUnSAL, and- CLSUnSAL under varying illumination, and is, otherwise, comparable with respect to these methods. However, while our method is significantly faster than FCLSU and GBM, it is slower than SUnSAL and CLSUnSAL by roughly an order of magnitude. Autors: Fadi Kizel;Maxim Shoshany;Nathan S. Netanyahu;Gilad Even-Tzur;Jón Atli Benediktsson; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 4925 - 4943 Publisher: IEEE
» A Stimulus-Independent Hybrid BCI Based on Motor Imagery and Somatosensory Attentional Orientation
 Abstract:Distinctive EEG signals from the motor and somatosensory cortex are generated during mental tasks of motor imagery (MI) and somatosensory attentional orientation (SAO). In this paper, we hypothesize that a combination of these two signal modalities provides improvements in a brain–computer interface (BCI) performance with respect to using the two methods separately, and generate novel types of multi-class BCI systems. Thirty two subjects were randomly divided into a Control-Group and a Hybrid-Group. In the Control-Group, the subjects performed left and right hand motor imagery (i.e., L-MI and R-MI). In the Hybrid-Group, the subjects performed the four mental tasks (i.e., L-MI, R-MI, L-SAO, and R-SAO). The results indicate that combining two of the tasks in a hybrid manner (such as L-SAO and R-MI) resulted in a significantly greater classification accuracy than when using two MI tasks. The hybrid modality reached 86.1% classification accuracy on average, with a 7.70% increase with respect to MI (), and 7.21% to SAO () alone. Moreover, all 16 subjects in the hybrid modality reached at least 70% accuracy, which is considered the threshold for BCI illiteracy. In addition to the two-class results, the classification accuracy was 68.1% and 54.1% for the three-class and four-class hybrid BCI. Combining the induced brain signals from motor and somatosensory cortex, the proposed stimulus-independent hybrid BCI has shown improved performance with respect to individual modalities, reducing the portion of BCI-illiterate subjects, and provided novel types of multi-class BCIs. Autors: Lin Yao;Xinjun Sheng;Dingguo Zhang;Ning Jiang;Natalie Mrachacz-Kersting;Xiangyang Zhu;Dario Farina; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1674 - 1682 Publisher: IEEE
» A Stochastic Adaptive Robust Optimization Approach for the Offering Strategy of a Virtual Power Plant
 Abstract:This paper proposes a novel approach for the offering strategy of a virtual power plant that participates in the day-ahead and the real-time energy markets. The virtual power plant comprises a conventional power plant, a wind-power unit, a storage facility, and flexible demands, which participate in the day-ahead and the real-time markets as a single entity in order to optimize their energy resources. We model the uncertainty in the wind-power production and in the market prices using confidence bounds and scenarios, respectively, which allows us to formul-ate the strategic offering problem as a stochastic adaptive robust optimization model. Results of a case study are provided to show the applicability of the proposed approach. Autors: Ana Baringo;Luis Baringo; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3492 - 3504 Publisher: IEEE
» A Stretchable Microneedle Electrode Array for Stimulating and Measuring Intramuscular Electromyographic Activity
 Abstract:We have developed a stretchablemicroneedle electrode array (sMEA) to stimulate andmeasure the electrical activity of muscle across multiple sites. The technology provides the signal fidelity and spatial resolution of intramuscular electrodesacross a large area of tissue. Our sMEA is composed of a polydimethylsiloxane (PDMS) substrate, conductive-PDMS traces, and stainless-steel penetrating electrodes. The traces and microneedles maintain a resistance of less than 10 when stretched up to a ~63% tensile strain, which allows for the full range of physiological motion of felinemuscle. The device and its constituent materials are cytocompatible for at least 28 days in vivo. When implanted in vivo, the device measures electromyographic (EMG) activity with clear compound motor unit action potentials. The sMEA also maintains a stable connection with moving muscle while electrically stimulating the tissue. This technology has direct application to wearable sensors, neuroprostheses, and electrophysiological studies of animals and humans. Autors: Gareth S. Guvanasen;Liang Guo;Ricardo J. Aguilar;Ashton L. Cheek;Chancellor S. Shafor;Swaminathan Rajaraman;T. Richard Nichols;Stephen P. DeWeerth; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1440 - 1452 Publisher: IEEE
» A Study of Solar Orbiter Spacecraft–Plasma Interactions Effects on Electric Field and Particle Measurements
 Abstract:We present numerical simulations of the Solar Orbiter spacecraft (SC)/plasma interaction performed with the SC–plasma interaction system software. Solar orbiter, to be launched in 2019, is dedicated to observe the sun and the solar wind. The SC will be equipped with both in situ and remote sensing instruments and will approach the sun as close as 0.28 AU. The whole SC will be subjected to an intense electromagnetic radiation flux (ten times that at the earth) leading to specific thermal and SC–plasma interactions issues. This paper investigates plasma interaction effects with two instruments: the radio and plasma waves and the electron analyzer system. Autors: Stanislas Guillemant;Milan Maksimovic;Alain Hilgers;Filippo Pantellini;Laurent Lamy;Philippe Louarn;Vincent Génot;Christopher J. Owen;Jean-Charles Matéo-Vélez;Pierre Sarrailh;Sébastien L. G. Hess;Antonio Vecchio; Appeared in: IEEE Transactions on Plasma Science Publication date: Sep 2017, volume: 45, issue:9, pages: 2578 - 2587 Publisher: IEEE
» A Study on Practically Unlimited Endurance of STT-MRAM
 Abstract:Magnetic tunnel junctions integrated for spin-transfer torque magnetoresistive random-access memory are by far the only known solid-state memory element that can realize a combination of fast read/write speed and high endurance. This paper presents a comprehensive validation of high endurance of deeply scaled perpendicular magnetic tunnel junctions (pMTJs) in light of various potential spin-transfer torque magnetoresistive random-access memory (STT-MRAM) use cases. A statistical study is conducted on the time-dependent dielectric breakdown (TDDB) properties and the dependence of the pMTJ lifetime on voltage, polarity, pulsewidth, duty cycle, and temperature. The experimental results coupled with TDDB models project write cycles. Furthermore, this work reports system-level workload characterizations to understand the practical endurance requirements for realistic memory applications. The results suggest that the cycling endurance of STT-MRAM is “practically unlimited,” which exceeds the requirements of various memory use cases, including high-performance applications such as CPU level-2 and level-3 caches. Autors: Jimmy J. Kan;Chando Park;Chi Ching;Jaesoo Ahn;Yuan Xie;Mahendra Pakala;Seung H. Kang; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3639 - 3646 Publisher: IEEE
» A Subpixel Target Detection Approach to Hyperspectral Image Classification
 Abstract:Hyperspectral image classification faces various levels of difficulty due to the use of different types of hyperspectral image data. Recently, spectral–spatial approaches have been developed by jointly taking care of spectral and spatial information. This paper presents a completely different approach from a subpixel target detection view point. It implements four stage processes, a preprocessing stage, which uses band selection (BS) and nonlinear band expansion, referred to as BS-then-nonlinear expansion (BSNE), a detection stage, which implements constrained energy minimization (CEM) to produce subpixel target maps, and an iterative stage, which develops an iterative CEM (ICEM) by applying Gaussian filters to capture spatial information, and then feeding the Gaussian-filtered CEM-detection maps back to BSNE band images to reprocess CEM in an iterative manner. Finally, in the last stage Otsu’s method is applied to converting ICEM-detected real-valued maps to discrete values for classification. The entire process is called BSNE-ICEM. Experimental results demonstrate BSNE-ICEM, which has advantages over support vector machine-based approaches in many aspects, such as easy implementation, fewer parameters to be used, and better false classification and precision rates. Autors: Bai Xue;Chunyan Yu;Yulei Wang;Meiping Song;Sen Li;Lin Wang;Hsian-Min Chen;Chein-I Chang; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 5093 - 5114 Publisher: IEEE
» A Supply-Demand Approach for Traffic-Oriented Wireless Resource Virtualization With Testbed Analysis
 Abstract:In face of the explosive service demands, solving the problem of spectrum scarcity is becoming more important than ever. To utilize the spectrum resources more thoroughly and efficiently, virtualization technologies have been proposed, which can be a means to mitigating resource granularity and increasing efficiency in heterogeneous network environments. In this paper, a traffic-oriented resource virtualization with demand-supply dynamic analysis is proposed for optimized resource allocation of heterogeneous networks with multiple types of services. On the supply side, i.e., the network side, a low-complexity matching game approach is introduced with the novel “Match-Degree” conception, which could be defined with the Grey relational analysis. The complexity of generating preference list can be reduced by unifying various dimensions of network parameters. On the demand side, i.e., the user side, bandwidth allocation algorithm is designed to consider the comprehensive network traffic characteristics, energy consumption, and network price factors, to maximize the overall utility. Except from theoretic analysis, simulation has also been employed to compare the proposed scheme with prior and traditional ones. To further verify the practicability, tractability, and effectiveness of the proposed demand-supply scheme, a test bed is designed and developed in this paper. Autors: Zhiyong Feng;Lei Ji;Qixun Zhang;Wei Li; Appeared in: IEEE Transactions on Wireless Communications Publication date: Sep 2017, volume: 16, issue:9, pages: 6077 - 6090 Publisher: IEEE
» A Survey of App Store Analysis for Software Engineering
 Abstract:App Store Analysis studies information about applications obtained from app stores. App stores provide a wealth of information derived from users that would not exist had the applications been distributed via previous software deployment methods. App Store Analysis combines this non-technical information with technical information to learn trends and behaviours within these forms of software repositories. Findings from App Store Analysis have a direct and actionable impact on the software teams that develop software for app stores, and have led to techniques for requirements engineering, release planning, software design, security and testing. This survey describes and compares the areas of research that have been explored thus far, drawing out common aspects, trends and directions future research should take to address open problems and challenges. Autors: William Martin;Federica Sarro;Yue Jia;Yuanyuan Zhang;Mark Harman; Appeared in: IEEE Transactions on Software Engineering Publication date: Sep 2017, volume: 43, issue:9, pages: 817 - 847 Publisher: IEEE
» A Survey on Story Generation Techniques for Authoring Computational Narratives
 Abstract:Computers are often used as tools to design, implement, and even visualize a variety of narrative forms. Many researchers and artists are now further attempting to engage the computer actively throughout the development of the narrative itself. Any form of computational narrative authoring is at some level always mixed-initiative , meaning that the processing capabilities of the computer are utilized with a varying degree to automate certain features of the authoring process. We structure this survey by focusing on two key components of stories, plot and space, and more specifically the degree to which these are either automated by the computer or authored manually. By examining the successes of existing research, we identify potential new research directions in the field of computational narrative. We also identify the advantages of developing a standard model of narrative to allow for collaboration between plot and space automation techniques. This would likely benefit the field of automated space generation with the strengths in the field of automated plot generation. Autors: Ben Kybartas;Rafael Bidarra; Appeared in: IEEE Transactions on Computational Intelligence and AI in Games Publication date: Sep 2017, volume: 9, issue:3, pages: 239 - 253 Publisher: IEEE
» A Switched Reluctance Motor Drive Using Photovoltaic Transistors: Principle, Prototype, Experimental, and Numerical Results
 Abstract:A solar-powered switch reluctance motor drive using photovoltaic transistors (PVTs) is presented. The expression “PVT” is used to designate a conventional photovoltaic (PV) cell used as a light-controlled power transistor. To obtain a motor drive, a set of PVTs controls the current fed from an external dc power source to the motor phases. The control is achieved by modulating the sunlight hitting the PVTs using a shutter driven by the motor rotor. If the external dc source is a solar panel, the resulting system is able to convert light energy into mechanical energy, without the need of any brushes or other power electronics components. This system could be more affordable and reliable than conventional ones, and therefore, is well suited for off-grid applications like water pumping. This paper first discusses the operation of a PVT through the proposition and the validation of a model. Then, the operating principle of a PVT inverter is clarified. Finally, experimental and numerical results on the first PVT inverter-fed switched reluctance motor are reported. A prototype was built using a switched reluctance motor 6/4 and 12 PVTs. It was here connected to an external 12 V dc power source as a step before using a solar PV source. Results that the PVT inverter-fed switched reluctance motor was operating as expected and provided useful power. Autors: Loïc Quéval;Alain Coty;Lionel Vido;Raimund Gottkehaskamp;Bernard Multon; Appeared in: IEEE Transactions on Industry Applications Publication date: Sep 2017, volume: 53, issue:5, pages: 4886 - 4893 Publisher: IEEE
» A Temperature Compensated Smart Nitrate-Sensor for Agricultural Industry
 Abstract:Extended research on the design and development of a smart nitrate sensor for monitoring nitrate concentration in surface and groundwater are reported in this paper. The developed portable sensing system consists of a planar interdigital sensor, associated electronics, instrumentation, and electrochemical impedance spectroscopy based analysis. The system is capable of measuring nitrate concentrations in the range of 0.01–0.5 mg/L in ground and surface water. This paper extends our earlier work by including a temperature compensation capacity within the sensor. WiFi-based Internet of Things (IoT) has been included, making it a connected sensing system. The system is capable of sending data directly to an IoT-based web server, which will be useful to develop distributed monitoring systems in the future. The developed system has the potential to monitor the impact of industrial, agricultural, or urban activity on water quality, in real time. Autors: Md. Eshrat E Alahi;Li Xie;Subhas Mukhopadhyay;Lucy Burkitt; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7333 - 7341 Publisher: IEEE
» A Theoretical Study of Velocity SAR Imaging of a Moving, Nonstationary Scene
 Abstract:The concept of the “velocity synthetic aperture radar” (VSAR)—a multiaperture sensor capable of measuring radial velocities in the scene and utilizing this information to correct motion-induced imaging distortions inherent to SAR—was proposed two decades ago. Lately, with the emergence of truly multichannel systems featuring antenna arrays with dozens of elements, the approach has been enjoying a renewed interest. The viability and effectiveness of the algorithm were successfully demonstrated in a series of airborne field campaigns that involved imaging both man-made targets and natural maritime features. These experiments and the wealth of resulting data also underscored the need for comprehensive mathematical descriptions of expected target signatures in the collected “image stacks” and for further refinements of the VSAR imaging theory. This paper addresses both tasks by building upon the available mathematical results developed for the along-track interferometric SAR imagery of distributed evolving targets. The approach allows simultaneous accounting for all essential effects known to impact SAR imagery of a target or an extended feature: its azimuth velocity, radial velocity and acceleration, as well as finite coherence time. The emphasis is on obtaining closed-form expressions that could readily illustrate the structure and behavior of the VSAR stack spectrum of such a target and help gauge anticipated focusing improvement stemming from the VSAR image correction. In particular, it is rigorously shown that the VSAR algorithm is successful in situations when SAR defocusing arises predominantly from radial motion and short coherence times—the resulting resolution is generally no worse than that of the corresponding real-aperture radar. On the other hand, strong defocusing due to azimuth translation may be problematic to compensate - ithin the VSAR approach framework. Autors: Jakov V. Toporkov; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 4972 - 4988 Publisher: IEEE
» A Threshold Voltage Model of Silicon-Nanotube-Based Ultrathin Double Gate-All-Around (DGAA) MOSFETs Incorporating Quantum Confinement Effects
 Abstract:In this paper, a quantum-mechanical threshold voltage model for ultrathin double gate-all-around DGAA MOSFETs has been developed by solving three-dimensional (3-D) Poisson's and 2-D Schrödinger's equations in the channel region. The parabolic potential approximation is considered for Poisson's equation solution, whereas a hollow cylindrical potential well in the channel region is assumed to solve Schrödinger's equation. Simple equations for the wave function and energy quantization in the channel of DGAA MOSFET have been formulated. Discretized energy levels have been used for channel charge calculation in subthreshold regime of device operation. The calculated channel charge is compared with a threshold charge to formulate the threshold voltage model. The effects of the device parameters such as the channel thickness, oxide thickness, doping, etc. on threshold voltage and DIBL have been extensively studied. The proposed model results have been verified by comparing with the numerical simulation results obtained from the 3-D device simulator Visual TCAD of Cogenda Int. Autors: Arun Kumar;Shiv Bhushan;Pramod Kumar Tiwari; Appeared in: IEEE Transactions on Nanotechnology Publication date: Sep 2017, volume: 16, issue:5, pages: 868 - 875 Publisher: IEEE
» A Threshold Voltage Model of Tri-Gate Junctionless Field-Effect Transistors Including Substrate Bias Effects
 Abstract:In this paper, the influence of substrate bias voltage and substrate-induced surface potential (SISP) on threshold voltage of tri-gate junctionless field-effect transistors (TG-JLFETs) has been investigated. For this purpose, a quasi-3-D threshold voltage model of TG-JLFETs is presented considering the effects of both back-bias voltage and a lightly doped substrate. To incorporate the effect of SISP on the threshold voltage, the boundary conditions at the silicon–buried oxide interface have been modified accounting for the potential difference between substrate surface and substrate bulk. Model results are compared with the simulation results obtained using 3-D visual TCAD device simulator from Cogenda. Autors: Deepti Gola;Balraj Singh;Pramod Kumar Tiwari; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3534 - 3540 Publisher: IEEE
» A Toeplitz Covariance Matrix Reconstruction Approach for Direction-of-Arrival Estimation
 Abstract:It is known that there exist two kinds of methods for direction-of-arrival (DOA) estimation in the literature: the subspace-based method and the sparsity-based method. However, pervious works reveal that the former method cannot address the case in which the number of signals is larger than that of sensors, whereas the latter one always suffers from the influence of basis mismatch. In this paper, to overcome these two shortcomings, we propose a new method called covariance matrix reconstruction approach (CMRA) for both uniform linear array and sparse linear array. In particular, by exploiting the Toeplitz structure of the covariance matrix of the array output, we formulate a low-rank matrix reconstruction (LRMR) problem for covariance matrix recovery. The nonconvex LRMR problem is then relaxed by replacing the rank norm with the nuclear norm and solved using the optimization toolbox. Next, we retrieve the DOAs from the recovered covariance matrix by using the subspace-based methods and obtain an estimated number of signals as a byproduct. We also provide two algorithm implementations for the LRMR problem based on duality and alternating direction method of multipliers, respectively. It is shown that CMRA can be regarded as an atomic norm minimization model or a gridless version of the sparsity-based methods and can recover more signals than sensors with a well-designed array. Numerical experiments are provided to validate the effectiveness of the proposed method, in comparison with some of the existing methods. Autors: Xiaohuan Wu;Wei-Ping Zhu;Jun Yan; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Sep 2017, volume: 66, issue:9, pages: 8223 - 8237 Publisher: IEEE
» A Total-Power Radiometer Front End in a 0.25- $\mu \text{m}$ BiCMOS Technology With Low $1/{f}$ -Corner
 Abstract:This paper describes the analysis, design, and characterization of a high-sensitivity millimeter-wave total-power radiometer front-end integrated into a 0.25- SiGe:C BiCMOS technology. This prototype is composed of a two cascode stage low-noise amplifier (LNA) and a voltage-driven common-emitter square-law detector. The LNA is interfaced to the detector through a low transformation ratio (i.e., high-impedance node) to achieve an efficient wideband signal transfer. The front end achieves both a low -noise corner and a low noise-equivalent power (NEP) by combining a large area, high resistive value load resistor together with a minimum size heterojunction bipolar transistor. At 56 GHz and optimum bias, the prototype provides a 61-MV/W responsivity which combined with a 194-nV/Hz white noise level result in a 3.2-fW/Hz NEP when the input power is modulated with a frequency above the 30-Hz flicker noise corner. The achieved 3-dB NEP bandwidth is 6 GHz. Autors: Satoshi Malotaux;Masoud Babaie;Marco Spirito; Appeared in: IEEE Journal of Solid-State Circuits Publication date: Sep 2017, volume: 52, issue:9, pages: 2256 - 2266 Publisher: IEEE
» A Two Channel System Approximation for Bandlimited Functions
 Abstract:The approximation of stable linear time-invariant (LTI) systems is studied for the Paley–Wiener space of bandlimited functions with absolutely integrable Fourier transform. For pointwise sampling, it is known that there exist stable LTI systems and functions such that the approximation process diverges, regardless of the oversampling factor. Recently, it was shown that the divergence can be overcome by using more general measurement functionals that are based on a complete orthonormal system. However, this approach requires the approximation process to have an increased bandwidth. In this paper, a two channel approximation process is presented that is uniformly convergent for all stable LTI systems and all functions in . An advantage of the two channel approach compared with the one channel approach is the reduction of the approximation bandwidth, which can be exactly the same as the input function bandwidth. Autors: Ullrich J. Mönich;Holger Boche; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 5496 - 5505 Publisher: IEEE
» A Two-Step Semiglobal Filtering Approach to Extract DTM From Middle Resolution DSM
 Abstract:Many filtering algorithms have been developed to extract the digital terrain model (DTM) from dense urban light detection and ranging data or the high-resolution digital surface model (DSM), assuming a smooth variation of topographic relief. However, this assumption breaks for a middle-resolution DSM because of the diminished distinction between steep terrains and nonground points. This letter introduces a two-step semiglobal filtering (TSGF) workflow to separate those two components. The first SGF step uses the digital elevation model of the Shuttle Radar Topography Mission to obtain a flat-terrain mask for the input DSM; then, a segmentation-constrained SGF is used to remove the nonground points within the flat-terrain mask while maintaining the shape of the terrain. Experiments are conducted using DSMs generated from Chinese ZY3 satellite imageries, verified the effectiveness of the proposed method. Compared with the conventional progressive morphological filter method, the usage of flat-terrain mask reduced the average root-mean-square error of DTM from 9.76 to 4.03 m, which is further reduced to 2.42 m by the proposed TSGF method. Autors: Yanfeng Zhang;Yongjun Zhang;Zhang Yunjun;Zongze Zhao; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1599 - 1603 Publisher: IEEE
» A Uniquified Virtualization Approach to Hardware Security
 Abstract:Virtualization has well-known security advantages for operating systems and software, but current techniques do not address increasingly important hardware-security concerns. For widely deployed systems (e.g., Internet of Things) and safety-critical systems (e.g., defense and automobiles), protecting against device tampering is critical, but is often unavoidable due to the relative ease of side-channel attacks. In this letter, we present a novel usage of virtualization that limits damage from bitstream tampering to a single instance of a deployed system by employing unique virtual architectures (i.e., overlays) on field-programmable gate arrays. Autors: Greg Stitt;Robert Karam;Kai Yang;Swarup Bhunia; Appeared in: IEEE Embedded Systems Letters Publication date: Sep 2017, volume: 9, issue:3, pages: 53 - 56 Publisher: IEEE
» A Unit Commitment Algorithm and a Compact MILP Model for Short-Term Hydro-Power Generation Scheduling
 Abstract:This paper presents a unit commitment algorithm that defines each unit discharge given the water head, the total plant downstream flow, the variable discharge upper limit, the unit efficiency curves, and the restricted operating zones in order to maximize power efficiency. This algorithm is part of the preprocessing phase that is intended to approximate a hydro-power production function that represents individualized unit decisions. A compact mixed-integer linear programming formulation, with fewer integer variables, based on an equivalent unit model and a piecewise linear generation function, is proposed. The unit commitment is integrated without increasing the model size and complexity due to the preprocessing phase. Moreover, the optimal aggregate decision is automatically converted to unit decisions by the proposed algorithm. The coordination with mid/long-term planning is performed by taking into account the power demand allocated to the hydro-power plants. Numerical tests on Brazilian hydro-power plants demonstrate that the proposed formulation has lower computational cost than unit individualized models considering a given accuracy level for the generation function approximation. Autors: Lucas S. M. Guedes;Pedro de Mendonça Maia;Adriano Chaves Lisboa;Douglas Alexandre Gomes Vieira;Rodney Rezende Saldanha; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3381 - 3390 Publisher: IEEE
» A User Trust System for Online Games—Part I: An Activity Theory Approach for Trust Representation
 Abstract:In virtual worlds (including computer games), users develop trust relationships from their in-world interactions with others. However, these trust relationships end up not being represented in the data structures (or databases) of such virtual worlds, though they sometimes appear associated with reputation and recommendation systems. In addition, as far as we know, the user is not provided with a personal trust tool to sustain his/her decision-making while he/she interacts with other users in the virtual or game world. In order to come up with a computational formal representation of these personal trust relationships, we need to succeed in converting in-world interactions into reliable sources of trust-related data. In this paper, we develop the required formalisms to gather and represent in-world interactions—which are based on the activity theory—as well as a method to convert in-world interactions into trust networks. In the companion paper, we use these trust networks to produce a computational trust decision based on subjective logic. This solution aims at supporting in-world user (or avatar) decisions about others in the game world. Autors: Rui Costa Cardoso;Abel J. P. Gomes;Mário M. Freire; Appeared in: IEEE Transactions on Computational Intelligence and AI in Games Publication date: Sep 2017, volume: 9, issue:3, pages: 305 - 320 Publisher: IEEE
» A Utility-Based Joint Subcarrier and Power Allocation for Green Communications in Multi-User Two-Way Regenerative Relay Networks
 Abstract:In this paper, we investigate utility-based joint subcarrier and power allocation algorithms for improving the energy efficiency (EE) in multi-user two-way regenerative relay networks. With the objective of determining the best subcarrier allocation for each user pair, subcarrier pairing permutation, and power allocation to all the nodes, a network price is introduced to the power consumption as a penalty for the achievable sum rate, followed by the examination of its impact on the tradeoff between the EE and spectral efficiency. The formulated optimization problem is a non-convex mixed-integer nonlinear programming problem, and thus a concave lower bound on the objective function and a series of convex transformations are applied to transform the problem into a convex one. Through dual decomposition, we propose a utility-based resource allocation algorithm for iteratively tightening the lower bound and finding the optimal solution of the primal problem. By exploring the structure of the obtained optimal solution, an optimal price that enables green resource allocation is found from the perspective of maximizing EE. Additionally, a suboptimal algorithm is investigated to strike a balance between computational complexity and optimality. Simulation results evince the effectiveness of the proposed algorithms. Autors: Keshav Singh;Ankit Gupta;Tharmalingam Ratnarajah; Appeared in: IEEE Transactions on Communications Publication date: Sep 2017, volume: 65, issue:9, pages: 3705 - 3722 Publisher: IEEE
» A Varying Frequency LPV-Based Control Strategy for Three-Phase Inverters
 Abstract:Grid-connected inverters have drawn a lot of attention in the integration of distributed generation systems and microgrids, as they are an effective interface for renewable and sustainable energy sources. Several strategies, including repetitive and resonant controllers, have been implemented in order to achieve low distortion and high-quality power. However, it has been proved that their performance decreases substantially when the grid frequency varies. This paper proposes a resonant control strategy based on a linear parameter varying (LPV) design, which is able to deal with changes in the network frequency. Controller aim is associated with injecting a clean sinusoidal current to the grid, even in the presence of nonlinear/unbalanced loads and/or grid-voltage distortions. Main emphasis is focused on presenting an applied LPV design procedure that covers plant modeling, controller synthesis, stability analysis, and experimental results that show the feasibility and effectiveness of the proposed scheme. Autors: Germán Andrés Ramos;René Alexander Soto-Perez;Jenny Alexandra Cifuentes; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7599 - 7608 Publisher: IEEE
» A Versatile Laminar Flow Atmospheric Pressure Plasma Jet Using a Double Coaxial Glass Tube
 Abstract:We report the characteristics of laminar flow atmospheric pressure plasma jets (APPJs) using a double coaxial glass tube. Two gases can be introduced independently into the tube, and the gas and plasma flows form a laminar flow and then interact outside of the glass tube. In the case of helium (He) as an inner gas flow with an outer nitrogen (N2) gas flow, emission lines of nitric oxide, the first negative and second positive system bands of N2 were observed, while only the second positive system band was observed in the case of argon (Ar) as the inner one. Considering the Penning effects of each excited state, the metastable state of He has a higher energy than that of Ar, resulting in energetic nitrogenous productions in the former case. The excited state in the core plasma is one of the important conditions to determine the characteristics of the APPJ produced with a double coaxial glass tube. Autors: Hayato Ohashi;Kohei Oyama;Tetta Mitani;Kenta Naiki;Tomohiro Nakayama;Hiroaki Ito; Appeared in: IEEE Transactions on Plasma Science Publication date: Sep 2017, volume: 45, issue:9, pages: 2481 - 2485 Publisher: IEEE
» A Wearable Hip Assist Robot Can Improve Gait Function and Cardiopulmonary Metabolic Efficiency in Elderly Adults
 Abstract:The aims of this paper were to investigate the effectiveness of a newly developed wearable hip assist robot, that uses an active assist algorithm to improve gait function, muscle effort, and cardiopulmonary metabolic efficiency in elderly adults. Thirty elderly adults (15 males/ 15 females) participated in thispaper. The experimental protocol consisted of overground gait at comfortable speed under three different conditions: free gait without robot assistance, robot-assisted gait with zero torque (RAG-Z), and full RAG. Under all conditions, muscle effort was analyzed using a 12-channel surface electromyography system. Spatio-temporal data were collected at 120 Hz using a 3-D motion capture system with six infrared cameras. Metabolic cost parameters were collected as oxygen consumption per unit (ml/min/kg) and aerobic energy expenditure (Kcal/min). In the RAG condition, participants demonstrated improved gait function, decreased muscle effort, and reduced metabolic cost. Although the hip assist robot only provides assistance at the hip joint, our results demonstrated a clear reduction in knee and ankle muscle activity in addition to decreased hip flexor and extensor activity. Our findings suggest that this robot has the potential to improve stabilization of the trunk during walking in elderly adults. Autors: Hwang-Jae Lee;Suhyun Lee;Won Hyuk Chang;Keehong Seo;Youngbo Shim;Byung-Ok Choi;Gyu-Ha Ryu;Yun-Hee Kim; Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering Publication date: Sep 2017, volume: 25, issue:9, pages: 1549 - 1557 Publisher: IEEE
» A Wide-Angle Scanning Phased Array With Microstrip Patch Mode Reconfiguration Technique
 Abstract:A method based on the microstrip patch mode and reconfiguration technique is analyzed, studied, and applied to wide-angle scanning phased arrays. First, a summative evaluation of microstrip patch modes available for wide-angle scanning or near endfire has been made. Second, to validate this new method, a multilayer microstrip patch element is established and its resonant modes TM01 and TM20 are excited. Third, a reconfigurable technique is used to reconfigure the above resonant modes and a wide joint 3-dB beam coverage is obtained. Fourth, a prototype of uniform linear phased array with the above reconfigurable elements is proposed. The prototype operates at 5.8 GHz and its main-beam direction can scan from −75° to +75° in the elevation plane with a gain fluctuation less than ±1 dB. Finally, in order to reduce the sidelobe levels, a hybrid particle swarm optimization algorithm is used to optimize the excitation amplitudes and phases. The measured results show an excellent wide-angle scanning performance, which validates the effectiveness of the proposed method. Autors: Xiao Ding;You-Feng Cheng;Wei Shao;Bing-Zhong Wang; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4548 - 4555 Publisher: IEEE
» A Wideband Low Cost and Optically Transparent Water Patch Antenna With Omnidirectional Conical Beam Radiation Patterns
 Abstract:A novel kind of optically transparent, low cost and wideband water patch antenna is demonstrated and analyzed. A significant feature of the proposed linearly polarized antenna is that both the patch and the ground plane are made of water. Thus, the whole structure becomes optically transparent except the small central feeding probe. The main radiators are made of water, which is available everywhere, low in cost and easy to be fabricated compared with other transparent materials. Results show that a wide impedance bandwidth of 35% for dB, a gain up to 4 dBi and symmetric omnidirectional conical beam radiation patterns with small cross-polarizations can be obtained. Due to the low cost and remarkable radiation performances, this novel transparent patch antenna is believed to have many promising applications in the future transparent electronics designs and flexible electronics. Autors: Jie Sun;Kwai-Man Luk; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4478 - 4485 Publisher: IEEE
» A Wideband Square-Slot Antenna Array With Superstrate and Electromagnetic Bandgap Reflector for 60-GHz Applications
 Abstract:A antenna array with wideband and high gain is proposed for 60-GHz applications. The operating bandwidth is from 57 to 66 GHz. A superstrate above and an electromagnetic bandgap reflector below the array structure increase peak gain and decrease backward radiation, respectively. This paper elaborates the design guidelines. The slot stubs are designed appropriately to increase the bandwidth of square-slot antenna and maintain the radiation pattern. The simulated and measured impedance bandwidth ( dB) are 28.8% (52.6–69.9 GHz) and 23.2% (52.6–66.5 GHz), respectively. The peak antenna gain ranging from 57 to 66 GHz is simulated to be 14.2–12.4 dBi, while the measured peak gain at 57, 60, 63, and 66 GHz are 13.6, 13.4, 12.6, and 11.3 dBi, respectively. The above results can satisfy requirement of many commercial applications. Autors: Chih-Yu Cheng;Jiun-Peng Chen;Hsin-Lung Su;Ken-Huang Lin; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4618 - 4625 Publisher: IEEE
» A Writing-Across-the-Curriculum Faculty Development Program: An Experience Report
 Abstract:This case study reports on the experiences of designing and assessing the effectiveness of a faculty development program on writing across the curriculum (WAC). The report focuses on the question: What are the key components of an effective faculty development program to integrate WAC into engineering and scientific courses taught by faculty in those disciplines? Situating the case: Two main models of WAC implementation exist: direct instruction, which uses writing specialists to deliver instruction to engineering and science students, and the department-centered model, which instructs faculty in engineering and scientific disciplines to teach writing as part of technical courses. How the case was studied: A report of the experiences of the authors and the feedback from the participants. About the case: The workshop was aimed at teachers in various disciplines and covered these main topics: fundamentals of writing theory and pedagogy, writing assignment design and assessment, and situating writing assignments in courses across the disciplinary curriculum. It took place over 10 weeks during a 15-week semester and included large- and small-group meetings, consultations with the members of the university WAC program, and peer review of writing assignment drafts. Conclusions, limitations, and suggestions for future research: Key challenges in developing the workshop included designing ways to bridge the conceptual gap between the participants' and WAC instructors' understanding of the role of writing in disciplinary courses, limited time available to the participants, and scheduling challenges. The workshop was given seven times. Most of the faculty participants (90%) generally found it to be very effective or effective. Studies of workshops with larger populations of trainees are suggested. Autors: Pavel Zemliansky;Landon Berry; Appeared in: IEEE Transactions on Professional Communication Publication date: Sep 2017, volume: 60, issue:3, pages: 306 - 316 Publisher: IEEE
» A Zero-Current Opening Circuit for Inductive Pulsed-Power Supply Based on High-Temperature Superconducting Pulsed-Power Transformer
 Abstract:The opening switch is one of the critical technologies in the development of inductive pulsed-power supply. The power requirement is very high when the opening switch is desired to commutate a large current. This paper presents a zero-current opening circuit for inductive pulsed-power supply based on a high-temperature superconducting pulsed-power transformer. First, there are two types of current flowing through the opening switch, one comes from the secondary side of the pulse transformer, and the other one comes from superconducting energy storage inductance. The orientation of the two current is opposite. Then, when the current flowing through the opening switch closes to zero, the switch is opened and this restrains the over-voltage pulse of the opening switch. The simulation results indicate that this zero-current opening circuit is feasible and has potential applications for high-energy systems in the future electromagnetic launcher. Autors: Xiaotong Zhang;Zhenmei Li;Haitao Li;Cunshan Zhang;Shucun Liu; Appeared in: IEEE Transactions on Plasma Science Publication date: Sep 2017, volume: 45, issue:9, pages: 2536 - 2540 Publisher: IEEE
» About Chairing the IEEE RAS Women in Engineering Committee [Women in Engineering]
 Abstract: Autors: Laura Margheri; Appeared in: IEEE Robotics & Automation Magazine Publication date: Sep 2017, volume: 24, issue:3, pages: 20 - 21 Publisher: IEEE
» AC-Inductors Design for a Modular Multilevel TSBC Converter, and Performance of a Low-Speed High-Torque Motor Drive Using the Converter
 Abstract:This paper provides a theoretical and experimental discussion on ac-inductors design for a modular multilevel triple-star bridge-cells (TSBC) converter, or shortly a TSBC converter. This converter requires multiple ac inductors for controlling nine cluster currents. This paper proposes three three-legged, six-winding, “interzigzag” inductors for the TSBC converter. Since each leg of the individual inductor has two windings, the three inductors have 18 windings in total. The wire leads are zigzagged among the three inductors. This unique structure of the “interzigzag” windings leads to the following feature: Both three-phase supply and motor currents produce no magnetic flux in each of the nine legs. This feature makes each inductor smaller in size and lighter in weight. A specially-designed downscaled motor-drive system rated at 400 V and 15 kW is constructed and tested to confirm the validity of a design of the proposed inductors, as well as to verify transient motor-drive performance during four-quadrant operation. Autors: Wataru Kawamura;Makoto Hagiwara;Hirofumi Akagi;Masahiko Tsukakoshi;Ritaka Nakamura;Sumiyasu Kodama; Appeared in: IEEE Transactions on Industry Applications Publication date: Sep 2017, volume: 53, issue:5, pages: 4718 - 4729 Publisher: IEEE
» Accuracy-Enhanced Algorithms for the Slot Leakage Inductance Computation of Double-Layer Windings
 Abstract:The paper presents original developments concerning the analytical computation of the slot leakage inductive parameters referring to unsaturated rotating electrical machines. In particular, the double-layer winding layout and arbitrary-shaped semi-closed slots are considered. The conventional analytical formulations of the self- and mutual-inductances of the two layers are initially presented, together with the algorithm developed for their computations. Then, the error causes laying on the simplifying assumptions are discussed and two corrections are applied to the conventional equations to enhance their accuracy with respect to finite element method estimations. Numerical examples of the magnetic energy stored in several slot geometrical domains are included in order to show the potentialities of the proposed analytical approach. Autors: Andrea Cavagnino; Appeared in: IEEE Transactions on Industry Applications Publication date: Sep 2017, volume: 53, issue:5, pages: 4422 - 4430 Publisher: IEEE
» Accurate and Fast Demodulation Algorithm for Multipeak FBG Reflection Spectra Using a Combination of Cross Correlation and Hilbert Transformation
 Abstract:We demonstrate a combined cross correlation and Hilbert transform-based demodulation algorithm for tracking the wavelength shifts of fiber Bragg gratings (FBGs) having a multiple peak reflection spectrum. We show how the Hilbert transform can be employed to convert the task of locating the maximum of the wavelength profile to the one of finding the zero crossing. We observed higher accuracy and fast response compared to other well-known demodulation algorithms such as the centroid detection algorithm and the cross-correlation algorithm. In addition, we show that the multipeak reflection spectrum that occurs in multimode fibers does not greatly affect the algorithm results. Finally, we experimentally recover axial strain measurements using a multipeak reflection spectrum of an FBG inscribed in a multimode gradient index CYTOP fiber using the newly developed algorithm. Autors: Antreas Theodosiou;Michael Komodromos;Kyriacos Kalli; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:18, pages: 3956 - 3962 Publisher: IEEE
» Accurate Heart Rate Monitoring During Physical Exercises Using PPG
 Abstract:Objective: The challenging task of heart rate (HR) estimation from the photoplethysmographic (PPG) signal, during intensive physical exercises, is tackled in this paper. Methods: The study presents a detailed analysis of a novel algorithm (WFPV) that exploits a Wiener filter to attenuate the motion artifacts, a phase vocoder to refine the HR estimate and user-adaptive post-processing to track the subject physiology. Additionally, an offline version of the HR estimation algorithm that uses Viterbi decoding is designed for scenarios that do not require online HR monitoring (WFPV+VD). The performance of the HR estimation systems is rigorously compared with existing algorithms on the publically available database of 23 PPG recordings. Results: On the whole dataset of 23 PPG recordings, the algorithms result in average absolute errors of 1.97 and 1.37 BPM in the online and offline modes, respectively. On the test dataset of 10 PPG recordings which were most corrupted with motion artifacts, WFPV has an error of 2.95 BPM on its own and 2.32 BPM in an ensemble with two existing algorithms. Conclusion: The error rate is significantly reduced when compared with the state-of-the art PPG-based HR estimation methods. Significance: The proposed system is shown to be accurate in the presence of strong motion artifacts and in contrast to existing alternatives has very few free parameters to tune. The algorithm has a low computational cost and can be used for fitness tracking and health monitoring in wearable devices. The MATLAB implementation of the algorithm is provided online. Autors: Andriy Temko; Appeared in: IEEE Transactions on Biomedical Engineering Publication date: Sep 2017, volume: 64, issue:9, pages: 2016 - 2024 Publisher: IEEE
» Accurate Modeling of Thermal Resistance for On-Wafer SiGe HBTs Using Average Thermal Conductivity
 Abstract:An accurate analytic model is proposed for estimating the junction temperature and thermal resistance in silicon–germanium heterojunction bipolar transistors (SiGe HBTs) including the back-end-of-line (BEOL) metal layers. The model uses an average value of thermal conductivity in order to include the temperature dependence of thermal resistance. The parameters corresponding to the thermal conductivity and the BEOL thermal resistance used in the model are extracted following a recently reported methodology. The proposed model is scalable in nature and verification with experimental data shows an excellent accuracy across different emitter geometries of SiGe HBTs fabricated in STMicroelectronics B9MW technology. Compact model simulations show that the proposed model simulates around 23% faster compared with an existing state-of-the-art iterative method. Autors: Suresh Balanethiram;Anjan Chakravorty;Rosario D’Esposito;Sebastien Fregonese;Didier Céli;Thomas Zimmer; Appeared in: IEEE Transactions on Electron Devices Publication date: Sep 2017, volume: 64, issue:9, pages: 3955 - 3960 Publisher: IEEE
» Achievable Rate and Energy Efficiency of Hybrid and Digital Beamforming Receivers With Low Resolution ADC
 Abstract:For 5G, it will be important to leverage the available millimeter wave spectrum. To achieve an approximately omnidirectional coverage with a similar effective antenna aperture compared with the state-of-the-art cellular systems, an antenna array is required at both the mobile and base stations. Due to the large bandwidth, the analog front-end of the receiver with a large number of antennas becomes especially power hungry. Two main solutions exist to reduce the power consumption: Hybrid BeamForming (HBF) and Digital BeamForming (DBF) with low resolution Analog to Digital Converters (ADCs). An HBF system can also be combined with low resolution ADCs. This paper compares the spectral and energy efficiency based on the RF-frontend configuration. A channel with multipath propagation is used. In contrast to previous publication, we take the spatial correlation of the quantization noise into account. We show that the low resolution ADC DBF is robust to small Automatic Gain Control (AGC) imperfections. We showed that in the low SNR regime, the performance of DBF even with 1–2 bit resolution outperforms HBF. If we consider the relationship of spectral and energy efficiency, DBF with 3–5 bit resolution achieves the best ratio of spectral efficiency per power consumption of the RF receiver frontend over a wide SNR range. The power consumption model is based on components reported in the literature. Autors: Kilian Roth;Josef A. Nossek; Appeared in: IEEE Journal on Selected Areas in Communications Publication date: Sep 2017, volume: 35, issue:9, pages: 2056 - 2068 Publisher: IEEE
» Achievable Rates of Space-Division Multiplexed Submarine Links Subject to Nonlinearities and Power Feed Constraints
 Abstract:We study the achievable rates of submarine fiber systems in the high-dimensional design space of variables including span length, launch power, number of spatial channels, and power feed current. We identify the regimes in which nonlinearities or power feed equipment constraints become dominant, and demonstrate that optimized system design evolves toward the linear regime as the system scales to a high number of spatial channels. We calculate the bit rate achievable by uniform and probabilistically shaped M-ary Quadrature Amplitude Modulation constellations to identify potential capacity-achieving implementations. Autors: Omar D. Domingues;Darli A. A. Mello;Reginaldo da Silva;Sercan Ö. Arık;Joseph M. Kahn; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:18, pages: 4004 - 4010 Publisher: IEEE
» Achieving Near Maximum Ratio Combining Diversity Gains With Directive Antennas
 Abstract:We present an empirically based comparison of the effectiveness of spatial and angular diversity systems in outdoor-to-indoor fixed wireless links. We concentrate on the simple to implement, single RF-chain selection diversity systems. We find that for such systems, angular diversity very significantly outperforms spatial diversity using comparatively sized arrays. This occurs despite the fact that our test environment is characterized by the presence of strong multipath propagation. Our results show that for a diversity order 20, the advantage of angular- over spatial-selection diversity is about 4 dB at the median level for non-line-of-sight (NLOS) links and close to 8 dB for the line-of-sight (LOS) case. When compared to the optimum maximum ratio combiner, the performance loss of angular selection diversity is 2 dB and 4 dB for LOS and NLOS, respectively. To provide a reference that explains the observed results we use a Ricean fading model that includes correlation, which is analyzed theoretically and via simulation. This model is found to match our measurement data very well and can, thus, be used to predict the performance of diversity systems for the type of settings we considered. Autors: Mauricio Rodríguez;Rodolfo Feick;Reinaldo A. Valenzuela;Dmitry Chizhik; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Sep 2017, volume: 66, issue:9, pages: 7782 - 7796 Publisher: IEEE
» Achieving Ultra Reliable Communication in 5G Networks: A Dependability Perspective Availability Analysis in the Space Domain
 Abstract:As part of the 5G communication paradigm, ultra reliable communication (URC) is envisaged as an important technology pillar for providing anywhere and anytime services to end users. While most existing studies on reliable communication do not investigate this problem from a dependability theory perspective, those dependability-based studies tend to define reliability merely in the time domain. In this letter, we advocate extending the concept of URC from the dependability perspective also in the space domain. We initiate definitions on cell availability and system availability. The availability and the probability of providing a guaranteed level of availability in a network are analyzed both/either cell-wise and/or system-wise. Poisson point process and Voronoi tessellation are adopted to model the spatial characteristics of cell deployment in both homogeneous and heterogeneous networks. Autors: H. V. Kalpanie Mendis;Frank Y. Li; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 2057 - 2060 Publisher: IEEE
» Acoustic Wave Filter Technology–A Review
 Abstract:Today, acoustic filters are the filter technology to meet the requirements with respect to performance dictated by the cellular phone standards and their form factor. Around two billion cellular phones are sold every year, and smart phones are of a very high percentage of approximately two-thirds. Smart phones require a very high number of filter functions ranging from the low double-digit range up to almost triple digit numbers in the near future. In the frequency range up to 1 GHz, surface acoustic wave (SAW) filters are almost exclusively employed, while in the higher frequency range, bulk acoustic wave (BAW) and SAW filters are competing for their shares. Prerequisites for the success of acoustic filters were the availability of high-quality substrates, advanced and highly reproducible fabrication technologies, optimum filter techniques, precise simulation software, and advanced design tools that allow the fast and efficient design according to customer specifications. This paper will try to focus on innovations leading to high volume applications of intermediate frequency (IF) and radio frequency (RF) acoustic filters, e.g., TV IF filters, IF filters for cellular phones, and SAW/BAW RF filters for the RF front-end of cellular phones. Autors: Clemens C. W. Ruppel; Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control Publication date: Sep 2017, volume: 64, issue:9, pages: 1390 - 1400 Publisher: IEEE
» ACStor: Optimizing Access Performance of Virtual Disk Images in Clouds
 Abstract:In virtualized data centers, virtual disk images (VDIs) serve as the containers in virtual environment, so their access performance is critical for the overall system performance. Some distributed VDI chunk storage systems have been proposed in order to alleviate the I/O bottleneck for VM management. As the system scales up to a large number of running VMs, however, the overall network traffic would become unbalanced with hot spots on some VMs inevitably, leading to I/O performance degradation when accessing the VMs. In this paper, we propose an adaptive and collaborative VDI storage system (ACStor) to resolve the above performance issue. In comparison with the existing research, our solution is able to dynamically balance the traffic workloads in accessing VDI chunks, based on the run-time network state. Specifically, compute nodes with lightly loaded traffic will be adaptively assigned more chunk access requests from remote VMs and vice versa, which can effectively eliminate the above problem and thus improves the I/O performance of VMs. We implement a prototype based on our ACStor design, and evaluate it by various benchmarks on a real cluster with 32 nodes and a simulated platform with 256 nodes. Experiments show that under different network traffic patterns of data centers, our solution achieves up to performance gain on VM booting time and VM's I/O throughput, in comparison with the other state-of-the-art approaches. Autors: Song Wu;Yihong Wang;Wei Luo;Sheng Di;Haibao Chen;Xiaolin Xu;Ran Zheng;Hai Jin; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Sep 2017, volume: 28, issue:9, pages: 2414 - 2427 Publisher: IEEE
» Active Disturbance Rejection Control of Linear Induction Motor
 Abstract:This paper proposes the theoretical framework and the experimental application of the active disturbance rejection control to linear induction motors. Such a nonlinear control (ADRC) technique can be viewed as a particular kind of input–output linearization control, where the nonlinear transformation of the state is not computed by means of the model, but it is estimated online. Such an approach permits to cope with unmodeling dynamics, as well as uncertainty in the knowledge of the model parameters and exogenous disturbances. The effectiveness of the proposed ADRC control law has been verified both by numerical simulations and experimentally on a suitably developed test setup. Moreover, the results have been compared with those achievable with the model-based feedback linearization control. Autors: Francesco Alonge;Maurizio Cirrincione;Filippo D’Ippolito;Marcello Pucci;Antonino Sferlazza; Appeared in: IEEE Transactions on Industry Applications Publication date: Sep 2017, volume: 53, issue:5, pages: 4460 - 4471 Publisher: IEEE
» Adaptation of Mode Filtering Technique in 4G-LTE Hybrid RoMMF-FSO for Last-Mile Access Network
 Abstract:This paper demonstrates a hybrid radio over multimode fibre and free space optics (RoMMF-FSO) system that can be used to extend the transmission range of the fourth generation long-term evolution (4G-LTE) signal in access networks. A single mode filtering technique (SMFT) is used to enhance 4G-LTE performance. The proposed scheme is evaluated in terms of the system transfer function, laser beam profile, and error vector magnitude (EVM). We show that using SMFT increases the RoMMF-FSO system bandwidth by 2 GHz and improves the received optical power by 13.6 dB. Moreover, the proposed system enhances the EVM by 4%. The measured results show that by using a 1 km MMF instead of a 1 km SMF will marginally increase the measured EVM from ~6.6% to ~7% with a 0.2 dB power penalty with respect to the LTE EVM limit of 12.5% as is specified for 16-quadrature amplitude modulation. The proposed system is validated practically under atmospheric turbulence conditions to mimic the outdoor environment. Measured EVM results are verified theoretically through transmitting LTE signals with turbulent using log-normal model. We also show that for a FSO link span of 500 m to meet the EVM target of 12.5% the SNR power penalties are ~2 dB and ~11 dB for Rytov variance of 1.2 × 10-4 and 0.1, respectively, compared with no turbulence. Autors: Hassan K. Al-Musawi;Tamas Cseh;Jan Bohata;Wai Pang Ng;Zabih Ghassemlooy;Stanislav Zvanovec;Eszter Udvary;Petr Pesek; Appeared in: Journal of Lightwave Technology Publication date: Sep 2017, volume: 35, issue:17, pages: 3758 - 3764 Publisher: IEEE
» Adapting Rate and Power for Maximizing Secrecy Energy Efficiency
 Abstract:We present the optimum rate and power adaptation rule that maximizes the average secrecy energy efficiency (SEE) subject to an average transmission power constraint. The SEE is defined as the outage secrecy capacity, the largest secrecy rate, such that the outage probability is less than a certain value, divided by the total power consumption (bits per joule). We characterize the SEE gain provided by varying the rate and/or the power, and discuss the impact of the number of antennas on the optimum adaptation rule. Autors: Hien Q. Ta;Sang Wu Kim; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 2049 - 2052 Publisher: IEEE
» Adapting Remote Sensing to New Domain With ELM Parameter Transfer
 Abstract:It is time consuming to annotate unlabeled remote sensing images. One strategy is taking the labeled remote sensing images from another domain as training samples, and the target remote sensing labels are predicted by supervised classification. However, this may lead to negative transfer due to the distribution difference between the two domains. To address this issue, we propose a novel domain adaptation method through transferring the parameters of extreme learning machine (ELM). The core of this method is learning a transformation to map the target ELM parameters to the source, making the classifier parameters of the target domain maximally aligned with the source. Our method has several advantages which was previously unavailable within a single method: multiclass adaptation through parameter transferring, learning the final classifier and transformation simultaneously, and avoiding negative transfer. We perform experiments on three data sets that indicate improved accuracy and computational advantages compared to baseline approaches. Autors: Suhui Xu;Xiaodong Mu;Dong Chai;Shuyang Wang; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1618 - 1622 Publisher: IEEE
» Adaptive 3D Virtual Learning Environments—A Review of the Literature
» Adaptive Appearance Modeling With Point-to-Set Metric Learning for Visual Tracking
 Abstract:In visual tracking, developing an efficient appearance model is a challenging task due to the influence of various factors, such as illumination variation, occlusion, background clutter, and so on. Existing tracking algorithms use appearance samples from previous frames to form a template set upon which target appearance models are built. However, these appearance models are data-dependent, so they may be corrupted by significant appearance variation. It is difficult to update the templates in challenging environments. In this paper, we propose a robust visual tracking algorithm with an adaptive appearance model using a point-to-set metric learning technique. To do this, we first model a target representation using a set of target templates and a regularized affine hull (RAH) spanned by the target templates. Then, we learn a point-to-set distance metric, which is incorporated into the optimization process to obtain an adaptive target representation. The RAH model covers unseen target appearances by affine combinations of the target templates. Based on the proposed target appearance model, we design an effective template update scheme by adjusting the weights of the target templates. Experimental results on challenging video sequences with comparisons to several state-of-the-art tracking algorithms demonstrate the effectiveness and robustness of the proposed tracking algorithm. Autors: Jun Wang;Yuanyun Wang;Hanzi Wang; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Sep 2017, volume: 27, issue:9, pages: 1987 - 2000 Publisher: IEEE
» Adaptive Centralized Clustering Framework for Software-Defined Ultra-Dense Wireless Networks
 Abstract:This paper develops a new centralized clustering framework to mitigate strong intercell interference in a software-defined ultra-dense network, where the number of clusters can be adapting to network conditions. A directed interference graph is designed to capture the dominant interference resulting from user mobility. An asymptotically optimal Max-K-Cut method is proposed to partition the graph, achieving a () approximation of the optimum in a polynomial time-complexity, where is the number of clusters. As a result, can be adaptively adjusted to leverage among the optimality loss, throughput, and complexity. Numerical results show that our adaptive centralized framework performs significantly better than other centralized or semidistributed clustering schemes in terms of throughput. Autors: Xinchen Lyu;Hui Tian;Wei Ni;Ren Ping Liu;Ping Zhang; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Sep 2017, volume: 66, issue:9, pages: 8553 - 8557 Publisher: IEEE
» Adaptive Clutter Demodulation for Non-Contrast Ultrasound Perfusion Imaging
 Abstract:Conventional Doppler ultrasound is useful for visualizing fast blood flow in large resolvable vessels. However, frame rate and tissue clutter caused by movement of the patient or sonographer make visualizing slow flow with ultrasound difficult. Patient and sonographer motion causes spectral broadening of the clutter signal, which limits ultrasound’s sensitivity to velocities greater than 5–10 mm/s for typical clinical imaging frequencies. To address this, we propose a clutter filtering technique that may increase the sensitivity of Doppler measurements to at least as low as 0.52 mm/s. The proposed technique uses plane wave imaging and an adaptive frequency and amplitude demodulation scheme to decrease the bandwidth of tissue clutter. To test the performance of the adaptive demodulation method at suppressing tissue clutter bandwidths due to sonographer hand motion alone, six volunteer subjects acquired data from a stationary phantom. Additionally, to test in vivo feasibility, arterial occlusion and muscle contraction studies were performed to assess the efficiency of the proposed filter at preserving signals from blood velocities 2 mm/s or greater at a 7.8 MHz center frequency. The hand motion study resulted in initial average bandwidths of 175 Hz (8.60mm/s), which were decreased to 10.5 Hz (0.52 mm/s) at −60 dB using our approach. The in vivo power Doppler studies resulted in 4.73 dB and 4.80 dB dynamic ranges of the blood flow with the proposed filter and 0.15 dB and 0.16 dB dynamic ranges of the blood flow with a conventional 50 Hz high-pass filter for the occlusion and contraction studies, respectively. Autors: Jaime Tierney;Crystal Coolbaugh;Theodore Towse;Brett Byram; Appeared in: IEEE Transactions on Medical Imaging Publication date: Sep 2017, volume: 36, issue:9, pages: 1979 - 1991 Publisher: IEEE
» Adaptive Communications for Stochastic Networks
 Abstract:Wireless networks have crucial needs for increasing efficiency in the spectrum usage. Adaptive communication is a key enabler for enhancing the spectral efficiency (SE) of wireless networks. This paper develops a framework for design and analysis of stochastic wireless networks, in which nodes employ diversity techniques and are randomly distributed in space. The signal-to-interference-plus-noise ratio (SINR) distribution is determined for finite and infinite stochastic networks at the output of the optimum combiner (OC). The statistics of the SINR at the OC output are used to design adaptive communication systems with diversity in the presence of small- and large-scale fading, interference, and noise. Slow adaptive modulation for any diversity order is analyzed in the presence of an interference field modeled as a Poisson point process. The results are applied to evaluate the benefits of adaptive modulation techniques with diversity for maximizing the SE in a stochastic network. Autors: Jinous Shafiei Dehkordi;Andrea Conti;Norman C. Beaulieu; Appeared in: IEEE Transactions on Vehicular Technology Publication date: Sep 2017, volume: 66, issue:9, pages: 8263 - 8275 Publisher: IEEE
» Adaptive Consensus of Nonlinear Multi-Agent Systems With Non-Identical Partially Unknown Control Directions and Bounded Modelling Errors
 Abstract:Existing Nussbaum function based results on consensus of multi-agent systems require that the unknown control directions of all the agents should be the same. This note proposes an adaptive method to relax such a requirement to allow non-identical control directions, under the condition that some control directions are known. Technically, a novel idea is proposed to construct a new Nussbaum function, from which a conditional inequality is developed to handle time-varying input gains. Then, the inequality is integrated with adaptive control technique such that the proposed Nussbaum function for each agent is adaptively updated. Moreover, in addition to parametric uncertainties, each agent has non-parametric bounded modelling errors which may include external disturbances and approximation errors of static input nonlinearities. Even in the presence of such uncertainties, the proposed control scheme is still able to ensure the states of all the agents asymptotically reach perfect consensus. Finally, simulation study is performed to show the effectiveness of the proposed approach. Autors: Ci Chen;Changyun Wen;Zhi Liu;Kan Xie;Yun Zhang;C. L. Philip Chen; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4654 - 4659 Publisher: IEEE
» Adaptive Feedforward Algorithm Without Grid Impedance Estimation for Inverters to Suppress Grid Current Instabilities and Harmonics Due to Grid Impedance and Grid Voltage Distortion
 Abstract:The performance of the grid-connected inverter was affected by the uncertainty of the grid conditions including the background distortion and the grid impedance. Typically, the feedforward of the grid voltage at the point of common coupling (PCC) highly suppressed the grid current harmonics caused by the grid voltage distortion; however, the PCC grid usually had a nonnegligible grid impedance, and the PCC voltage feedforward aroused serious grid current harmonics or instability. This study proposes a novel adaptive algorithm for the PCC voltage feedforward to work well with the varied grid impedance. In the proposal, the band-pass filters at the harmonic frequencies are used to detect the variation of the grid impedance as well as to facilitate the adaptive PCC voltage feedforward. It is not necessary to inject an additional harmonic to estimate the grid impedance. The basic principles as well as the realization and logic of the proposed algorithm are detailed, and some selected waveforms are provided to verify the superior performance. Compared with the typical robust design or adaptive control, the proposed algorithm does not have to sacrifice the dynamic or the harmonics rejection performance, or to use the on or offline grid impedance estimation. Autors: Jinming Xu;Shaojun Xie;Qiang Qian;Binfeng Zhang; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7574 - 7586 Publisher: IEEE
» Adaptive Inter CU Depth Decision for HEVC Using Optimal Selection Model and Encoding Parameters
 Abstract:High efficiency video coding adopts a new hierarchical coding structure, including coding unit (CU), prediction unit (PU), and transform unit to achieve higher coding efficiency than its predecessor H.264/AVC high profile. However, its hierarchical unit partitioning strategy leads to huge computational complexity. In this paper, an adaptive inter CU depth decision algorithm is proposed, which exploits both temporal correlation of CU depth and available encoding parameters. An optimal selection model of CU depth is established to estimate the range of candidate CU depth by exploiting the temporal correlation of CU depth among current CU and temporally co-located CUs. To reduce the accumulated errors in the process of CU depth prediction, the maximum depth of the co-located CUs and the coded block flag (CBF) of the current CU are used. Moreover, PU size and CBF information are also used to decide the maximum depth for the current CU. Experimental results show that the proposed CU depth decision approach reduces 56.3% and 51.5% average encoding time, and the Bjontegaard delta bit rate increases only 1.3% and 1.1% for various test sequences under the random access and the low delay B conditions, respectively. Autors: Yue Li;Gaobo Yang;Yapei Zhu;Xiangling Ding;Xingming Sun; Appeared in: IEEE Transactions on Broadcasting Publication date: Sep 2017, volume: 63, issue:3, pages: 535 - 546 Publisher: IEEE
» Adaptive Robust Transmission Expansion Planning Using Linear Decision Rules
 Abstract:This paper presents a novel model for two-stage adaptive robust transmission expansion planning (AR-TEP) problem considering the uncertainty of future load demand and future wind power production. Linear decision rules (LDRs) are utilized to reformulate the AR-TEP model as a tractable mixed-integer linear programming problem, which can be directly solved by off-the-shelf optimization packages. The proposed LDR-based AR-TEP model is illustrated using the Garver 6-bus test system, the IEEE 24-bus reliability test system, and a 236-bus test system under different conditions and compared with a decomposition-based AR-TEP model that uses primal cutting planes. Also, the robustness of the expansion plans obtained from these two AR-TEP models is evaluated by carrying out an ex-post out-of-sample analysis for different values of the budget of uncertainty. Simulation results demonstrate the effectiveness of the proposed LDR-based AR-TEP model. Autors: Shahab Dehghan;Nima Amjady;Antonio J. Conejo; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 4024 - 4034 Publisher: IEEE
» Adaptive Tuning of Large-Signal Resonant Circuits Using Phase-Switched Fractional Capacitance
 Abstract:Inductively coupled systems used in applications such as RFID and wireless power often require high factor resonant transmitters to maximize the magnetic field and achieve high overall efficiency. However, these are sensitive to environmental detuning as well as component tolerances. Existing methods for accurate tuning require search algorithms, usually requiring the suspension of normal operation in order to calibrate the resonant inductor–capacitor circuit, thus reducing power throughput and increasing system complexity. We describe here how zero-voltage switched fractional capacitance techniques may be used to achieve continuous and real-time adaptive tuning of large-signal resonant inductor–capacitor circuits. Minimal additional circuitry is required and tuning is maintained without disrupting normal operation. Many variants are possible for the implementation of the system, and some tradeoffs relating to the available tuning range and operating voltages are analyzed for two alternative topologies. Experimental results are presented for a 125-kHz demonstration system. Autors: W. Redman-White;H. Kennedy;R. Bodnar;T. Lee; Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs Publication date: Sep 2017, volume: 64, issue:9, pages: 1072 - 1076 Publisher: IEEE
» Adaptive-Robust Time-Delay Control for a Class of Uncertain Euler–Lagrange Systems
 Abstract:This paper proposes a new adaptive-robust control (ARC) strategy for a tracking control problem of a class of uncertain Euler–Lagrange systems. The proposed adaptive-robust time-delay control (ARTDC) amalgamates the ARC strategy with the time-delay control (TDC). It comprises three parts: a time-delay estimation part, a desired dynamics injection part, and an adaptive-robust part. The main feature of the proposed ARTDC is that it does not involve any threshold value in its adaptive law; thus, it allows the switching gain to increase or decrease whenever the error trajectories move away or close to the switching surface, respectively. Thus, compared with the existing ARC schemes, ARTDC is able to alleviate the over- and underestimation problems of the switching gain. Moreover, the stability analysis of ARTDC provides an upper bound for the selection of sampling interval and its relation with controller gains. The proposed ARTDC shows improved tracking performance compared with the TDC and the existing adaptive sliding-mode control in simulations as well as in experiments with a multiple-degree-of-freedom system. Autors: Spandan Roy;Indra Narayan Kar;Jinoh Lee;Maolin Jin; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7109 - 7119 Publisher: IEEE
» Advanced Engine Cooling System Subjected to Ram Air Effect—Nonlinear Adaptive Multiple Input and Multiple Output (NAMIMO) Control
» Advanced Synchronizing Systems for Offshore Power Systems: Improving System Reliability and Flexibility
 Abstract:Small power systems, such as those found on offshore platforms, are fragile, yet they must operate reliably for economy and the safety of both personnel and the environment. These systems often include combustion turbine generators for the main process power requirements and black start diesel generators that can supply essential and emergency buses; the diesel generators can also be used to restart the main generation systems in the event of a power-system collapse. The power distribution systems on these offshore platforms have built-in redundancy with multiple circuits to supply critical loads for fault tolerance and operating flexibility. A system to easily and safely synchronize islanded buses via many possible synchronization points can revolutionize the operational flexibility and, therefore, the safety and reliability of the power system. This article reports on advanced synchronizing systems installed on two offshore platforms. Autors: Michael J. Thompson;Allen Li;Roy Luo;Michael C. Tu;Iris Urdaneta; Appeared in: IEEE Industry Applications Magazine Publication date: Sep 2017, volume: 23, issue:5, pages: 60 - 69 Publisher: IEEE
» Advances in Signal Processing for GNSSs [From the Guest Editors]
 Abstract: Autors: Pau Closas;Marco Luise;Jose-Angel Avila-Rodriguez;Christopher Hegarty;Jiyun Lee; Appeared in: IEEE Signal Processing Magazine Publication date: Sep 2017, volume: 34, issue:5, pages: 12 - 15 Publisher: IEEE
» Aggregating Rich Hierarchical Features for Scene Classification in Remote Sensing Imagery
 Abstract:Scene classification is one of the most important issues in remote sensing image processing. To obtain a high discriminative feature representation for an image to be classified, traditional methods usually consider to densely accumulate hand-crafted low-level descriptors (e.g., scale-invariant feature transform) by feature encoding techniques. However, the performance is largely limited by the hand-crafted descriptors as they are not capable of describing the rich semantic information contained in various remote sensing images. To alleviate this problem, we propose a novel method to extract discriminative image features from the rich hierarchical information contained in convolutional neural networks (CNNs). Specifically, the low-level and middle-level intermediate convolutional features are, respectively, encoded by vector of locally aggregated descriptors (VLAD) and then reduced by principal component analysis to obtain hierarchical global features; meanwhile, the fully connected features are average pooled and subsequently normalized to form new global features. The proposed encoded mixed-resolution representation (EMR) is the concatenation of all the above-mentioned global features. Due to the usage of encoding strategies (VLAD and average pooling), our method can deal with images of different sizes. In addition, to reduce the computational consumption in the training stage, we directly extract EMR from VGG-VD and ResNet pretrained on the ImageNet dataset. We show in this paper that CNNs pretrained on the natural image dataset are more easily applied to the remote sensing dataset when the local structure similarity between two datasets is higher. Experimental evaluations on the UC-Merced and Brazilian Coffee Scenes datasets demonstrate that our method is superior to the state of the art. Autors: Guoli Wang;Bin Fan;Shiming Xiang;Chunhong Pan; Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Publication date: Sep 2017, volume: 10, issue:9, pages: 4104 - 4115 Publisher: IEEE
» Ahura: A Heuristic-Based Racer for the Open Racing Car Simulator
 Abstract:Designing automatic drivers for car racing is an active field of research in the area of robotics and artificial intelligence. A controller called Ahura (a heuristic-based racer) for the open racing car simulator is proposed in this paper. Ahura includes five modules, namely steer controller, speed controller, opponent manager, dynamic adjuster, and stuck handler. These modules have 23 parameters all together that are tuned using an evolutionary strategy for a particular car to ensure fast and safe drive on different tracks. These tuned parameters are further modified by the dynamic adjuster module during the run according to the width, friction, and dangerous zones of the track. The dynamic adjustment enables Ahura to decide on-the-fly based on the current situation; hence, it eliminates the need for prior knowledge about the characteristics of the track. The driving performance of Ahura is compared with other state-of-the-art controllers on 40 tracks when they drive identical cars. Our experiments indicate that Ahura performs significantly better than other controllers in terms of damage and completion time especially on complex tracks (road tracks). Also, experiments show that the overtaking strategy of Ahura is safer and more effective compared to other controllers. Autors: Mohammad Reza Bonyadi;Zbigniew Michalewicz;Samadhi Nallaperuma;Frank Neumann; Appeared in: IEEE Transactions on Computational Intelligence and AI in Games Publication date: Sep 2017, volume: 9, issue:3, pages: 290 - 304 Publisher: IEEE
» Air-Ground Channel Characterization for Unmanned Aircraft Systems—Part IV: Airframe Shadowing
» Air-SSLAM: A Visual Stereo Indoor SLAM for Aerial Quadrotors
 Abstract:In this letter, we introduce a novel method for visual simultaneous localization and mapping (SLAM)—so-called Air-SSLAM—which exploits a stereo camera configuration. In contrast to monocular SLAM, scale definition and 3-D information are issues that can be more easily dealt with in stereo cameras. Air-SSLAM starts from computing keypoints and the correspondent descriptors over the pair of images, using good features-to-track and rotated-binary robust-independent elementary features, respectively. Then a map is created by matching each pair of right and left frames. The long-term map maintenance is continuously performed by analyzing the quality of each matching, as well as by inserting new keypoints into uncharted areas of the environment. Three main contributions can be highlighted in our method: 1) a novel method to match keypoints efficiently; 2) three quality indicators with the aim of speeding up the mapping process; and 3) map maintenance with uniform distribution performed by image zones. By using a drone equipped with a stereo camera, flying indoor, the translational average error with respect to a marked ground truth was computed, demonstrating promising results. Autors: Pompilio Araújo;Rodolfo Miranda;Diedre Carmo;Raul Alves;Luciano Oliveira; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1643 - 1647 Publisher: IEEE
» Airborne Transient Electromagnetic Modeling and Inversion Under Full Attitude Change
 Abstract:During airborne transient electromagnetic (EM) surveys, transmitting and receiving antennas change their attitudes as the inevitable result of pilot maneuvers and natural forces, which makes the EM response different from that of the nominal attitudes when the antennas are straight and level. Attitude changes were usually neglected or partially considered in the past, which are not adequate for a quantitative interpretation. In this letter, we first scrutinize the mechanism of how the attitude change affects the EM response and divides these effects into two parts: the pure attitude effect and the resultant translation effect. Then, we introduce a novel method to involve the full attitude change in both modeling and inversion. Our compelling results finally demonstrate that the attitude change affects the early-time response much more than the late time and involving the full change in inversion can produce a better estimate of shallow geoelectric parameters. Autors: Youzheng Qi;Ling Huang;Xucun Wang;Guangyou Fang;Gang Yu; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1575 - 1579 Publisher: IEEE
 Abstract:The combination of ultra-low-power wireless communications and energy harvesting enables the realization of autonomous wireless sensor networks. Such networks can be usefully applied in commercial aircraft where wireless sensing solutions contribute to weight reduction and increased ease of installation and maintenance. This paper presents, for the first time, a complete energy-autonomous wireless strain monitoring system for aircraft. The system is based on a multimode wireless time-division multiple access (TDMA) medium access control (MAC) protocol that supports automatic configuration and a time-stamping accuracy better than 1 ms. The energy supply depends solely on an innovative thermoelectric energy harvester, which takes advantage of the changes in environmental temperature during takeoff and landing. The system was successfully integrated and passed the functional and flight-clearance tests that qualify it for use in a flight-test installation. Autors: L. V. Allmen;G. Bailleul;Th. Becker;J.-D. Decotignie;M. E. Kiziroglou;C. Leroux;P. D. Mitcheson;J. Müller;D. Piguet;T. T. Toh;A. Weisser;S. W. Wright;E. M. Yeatman; Appeared in: IEEE Transactions on Industrial Electronics Publication date: Sep 2017, volume: 64, issue:9, pages: 7284 - 7292 Publisher: IEEE
» Airport Detection Based on a Multiscale Fusion Feature for Optical Remote Sensing Images
 Abstract:Automatically detecting airports from remote sensing images has attracted significant attention due to its importance in both military and civilian fields. However, the diversity of illumination intensities and contextual information makes this task difficult. Moreover, auxiliary features both within and surrounding the regions of interest are usually ignored. To address these problems, we propose a novel method that uses a multiscale fusion feature to represent the complementary information of each region proposal, which is extracted by constructing a GoogleNet with a light feature module model that has an additional light fully connected layer. Then, the fusion feature is input to a support vector machine whose performance is enhanced using a hard negative mining method. Finally, a simplified localization method is applied to tackle the problem of box redundancy and to optimize the locations of airports. An experiment demonstrates that the fusion feature outperforms other features on airport detection tasks from remote sensing images containing complicated contextual information. Autors: Zhifeng Xiao;Yiping Gong;Yang Long;Deren Li;Xiaoying Wang;Hua Liu; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1469 - 1473 Publisher: IEEE
» Algorithm and Architecture Design of Adaptive Filters With Error Nonlinearities
 Abstract:This paper presents a framework based on the logarithmic number system to implement adaptive filters with error nonlinearities in hardware. The framework is demonstrated through pipelined implementations of two recently proposed adaptive filtering algorithms based on logarithmic cost, namely, least mean logarithmic square (LMLS) and least logarithmic absolute difference (LLAD). To the best of our knowledge, the proposed architectures are the first attempts to implement both LMLS and LLAD algorithms in hardware. We derive error computing algorithms to realize the nonlinear error functions for LMLS and LLAD and map them onto hardware. We also propose a novel variable- scheme to enhance the original LMLS algorithm and prove its robustness and suitability for VLSI implementations in practical applications. Detailed bit width and error analysis are carried out for the proposed VLSI fixed point implementations. Postlayout implementation results show that with an additional multiplier over conventional least mean square (LMS), 7-dB improvement in steady-state mean square deviation performance can be achieved and with the proposed variable- scheme, 12-dB improvement can be achieved without compromising the convergence. We will show that LMLS can potentially replace LMS in practical applications, by demonstrating a proof-of-concept by extending the framework to transform domain adaptive filters. Autors: Subrahmanyam Mula;Vinay Chakravarthi Gogineni;Anindya Sundar Dhar; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Sep 2017, volume: 25, issue:9, pages: 2588 - 2601 Publisher: IEEE
» All Analog Processing of Speckle Affected Self-Mixing Interferometric Signals
 Abstract:Self-mixing (SM) or optical feedback interferometry has been extensively used for high precision displacement and vibration sensing. However, presence of speckle can significantly degrade the SM interferometric signal and cause changes in signal amplitude as well as in the operating optical feedback regime, resulting in reduction in measurement precision. Previously, different advanced digital signal processing techniques have been proposed to undo the effects caused by speckle. However, their complex and computationally heavy nature inhibits their use for real-time, high bandwidth sensing applications. In this regard, an all analog signal processing algorithm has been presented in this paper, which allows real-time processing of speckle affected SM signal while using standard analog circuits. Various simulations indicated that it is able to correctly process speckle affected SM signals having amplitude variation of at least one order and optical feedback parameter reduction until 0.5. This proposed algorithm has been tested on experimentally acquired speckle affected SM signals and found capable of dealing with variations in optical feedback regime and amplitude modulation of SM signals, in accordance with simulation results. The developed hardware prototype circuit measures a maximum displacement amplitude of 0.4 mm at a maximum target velocity of 8 mm/s for an SM sensor with a laser wavelength of 785 nm as long as . The proposed all analog processing could be a significant step toward a robust, low-cost, integrated, real-time SM displacement sensor. Autors: Asra A. Siddiqui;Usman Zabit;Olivier D. Bernal;Gulistan Raja;Thierry Bosch; Appeared in: IEEE Sensors Journal Publication date: Sep 2017, volume: 17, issue:18, pages: 5892 - 5899 Publisher: IEEE
» All-Digital Calibration of Timing Mismatch Error in Time-Interleaved Analog-to-Digital Converters
 Abstract:This paper presents an all-digital background calibration for timing mismatch in time-interleaved analog-to-digital converters (TI-ADCs). It combines digital adaptive timing mismatch estimation and digital derivative-based correction, achieving lower hardware cost and better suppression of timing mismatch tones than previous work. In addition, for the first time closed-form exact expressions for the signal-to-noise and distortion ratio (SNDR) of a four-channel TI-ADC with timing mismatch after derivative-based digital correction are obtained, which can be used to guide the design. Simulation results of a four-channel TI-ADC behavioral model and measurement results from a commercial 12-bit 3.6-GS/s two-channel TI-ADC show that the proposed all-digital calibration can accurately estimate the timing skew and effectively correct the timing mismatch errors, while also confirming the analytic SNDR expressions. Autors: Shuai Chen;Luke Wang;Hong Zhang;Rosanah Murugesu;Dustin Dunwell;Anthony Chan Carusone; Appeared in: IEEE Transactions on Very Large Scale Integration Systems Publication date: Sep 2017, volume: 25, issue:9, pages: 2552 - 2560 Publisher: IEEE
» AllFocus: Patch-Based Video Out-of-Focus Blur Reconstruction
 Abstract:Amateur videos always contain focusing issues. A focusing mistake may produce out-of-focus blur, which seriously degrades the expressive force of the video. In this paper, we propose a patch-based method to remove the out-of-focus blur of a video and build an all-in-focus video. We assume that the out-of-focus blurry region in one frame will be clear in a portion of other frames; thus, the clear corresponding regions can be used to reconstruct the blurry one. We divide each video frame into a grid of patches and track each patch in the surrounding frames. We independently reconstruct each video frame by building a Markov random field model to identify the optimal target patches that are sharp, similar to the original patches, and are coherent with their neighboring patches within the overlapped regions. To recover an all-in-focus video, an iterative framework is utilized, in which the reconstructed video of each iteration is substituted in the next iteration. Finally, we employ the idea of a bilateral filter to temporally smooth the reconstructed video. The experimental results and the comparison with the previous works demonstrate the effectiveness of our method. Autors: Yinting Wang;Zhenyang Wang;Dapeng Tao;Shaojie Zhuo;Xianghua Xu;Shiliang Pu;Mingli Song; Appeared in: IEEE Transactions on Circuits and Systems for Video Technology Publication date: Sep 2017, volume: 27, issue:9, pages: 1895 - 1908 Publisher: IEEE
» Almost Lossless Analog Signal Separation and Probabilistic Uncertainty Relations
 Abstract:We propose an information-theoretic framework for analog signal separation. Specifically, we consider the problem of recovering two analog signals, modeled as general random vectors, from the noiseless sum of linear measurements of the signals. Our framework is inspired by the groundbreaking work of Wu and Verdú (2010) on analog compression and encompasses, inter alia, inpainting, declipping, super-resolution, the recovery of signals corrupted by impulse noise, and the separation of (e.g., audio or video) signals into two distinct components. The main results we report are general achievability bounds for the compression rate, i.e., the number of measurements relative to the dimension of the ambient space the signals live in, under either measurability or Hölder continuity imposed on the separator. Furthermore, we find a matching converse for sources of mixed discrete-continuous distribution. For measurable separators our proofs are based on a new probabilistic uncertainty relation, which shows that the intersection of generic subspaces with general sets of sufficiently small Minkowski dimension is empty. Hölder continuous separators are dealt with by introducing the concept of regularized probabilistic uncertainty relations. The probabilistic uncertainty relations we develop are inspired by embedding results in dynamical systems theory due to Sauer et al. (1991) and—conceptually—parallel classical Donoho-Stark and Elad-Bruckstein uncertainty principles at the heart of compressed sensing theory. Operationally, the new uncertainty relations take the theory of sparse signal separation beyond traditional sparsity—as measured in terms of the number of non-zero entries—to the more general notion of low description complexity as quantified by Minkowski dimension. Finally, our approach also allows to significantly strengthen- key results in Wu and Verdú (2010). Autors: David Stotz;Erwin Riegler;Eirikur Agustsson;Helmut Bölcskei; Appeared in: IEEE Transactions on Information Theory Publication date: Sep 2017, volume: 63, issue:9, pages: 5445 - 5460 Publisher: IEEE
» Almost Tight Spectral Graph Wavelets With Polynomial Filters
 Abstract:The construction of spectral filters for graph wavelet transforms is addressed in this paper. Both the undecimated and decimated cases will be considered. The filter functions are polynomials and can be implemented efficiently without the need for any eigendecomposition, which is computationally expensive for large graphs. Polynomial filters also have the advantage of the vertex localization property. The construction is achieved by designing suitable transformations that are used on traditional multirate filter banks. It will be shown how the classical quadrature-mirror-filters and linear phase, critically/over- sampled filter banks can be used to construct spectral graph wavelets that are almost tight. A variety of design examples will be given to show the versatility of the design technique. Autors: David B. H. Tay;Yuichi Tanaka;Akie Sakiyama; Appeared in: IEEE Journal of Selected Topics in Signal Processing Publication date: Sep 2017, volume: 11, issue:6, pages: 812 - 824 Publisher: IEEE
» Alternative Surface Integral Equation Formulations for Characteristic Modes of Dielectric and Magnetic Bodies
 Abstract:In this paper, the physical meanings and various computing methods of characteristic modes (CMs) of dielectric and magnetic bodies are investigated. Two types of surface integral equation (SIE) formulations based on the dependent relationships between the equivalent surface electric and magnetic currents are proposed. Following the two types of SIE formulations, two generalized eigenvalue equations are established to determine the CMs of dielectric or magnetic bodies. This is in contrast to the approach using induced volume currents. It is found that the eigenvalues possess clear physical meanings similar to those of perfectly electric conducting bodies. The CMs can be used to describe the resonant features, including resonant frequencies and resonant field distributions. Numerical results are presented to validate the proposed formulations. Autors: Renzun Lian;Jin Pan;Shaode Huang; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4706 - 4716 Publisher: IEEE
» Alzheimer’s Disease Classification Based on Individual Hierarchical Networks Constructed With 3-D Texture Features
» Ambient Backscatter: A New Approach to Improve Network Performance for RF-Powered Cognitive Radio Networks
 Abstract:This paper introduces a new solution to improve the performance for secondary systems in radio frequency (RF) powered cognitive radio networks (CRNs). In a conventional RF-powered CRN, the secondary system works based on the harvest-then-transmit protocol. That is, the secondary transmitter (ST) harvests energy from primary signals and then uses the harvested energy to transmit data to its secondary receiver (SR). However, with this protocol, the performance of the secondary system is much dependent on the amount of harvested energy as well as the primary channel activity, e.g., idle and busy periods. Recently, ambient backscatter communication has been introduced, which enables the ST to transmit data to the SR by backscattering ambient signals. Therefore, it is potential to be adopted in the RF-powered CRN. We investigate the performance of RF-powered CRNs with ambient backscatter communication over two scenarios, i.e., overlay and underlay CRNs. For each scenario, we formulate and solve the optimization problem to maximize the overall transmission rate of the secondary system. Numerical results show that by incorporating such two techniques, the performance of the secondary system can be improved significantly compared with the case when the ST performs either harvest-then-transmit or ambient backscatter technique. Autors: Dinh Thai Hoang;Dusit Niyato;Ping Wang;Dong In Kim;Zhu Han; Appeared in: IEEE Transactions on Communications Publication date: Sep 2017, volume: 65, issue:9, pages: 3659 - 3674 Publisher: IEEE
» An AC Power Standard for Loss Measurement Systems for Testing Power Transformers
 Abstract:An ac power standard for high voltages and high currents for power frequencies is presented. It consists of commercially available components and is traceable to the primary standards of Physikalisch-Technische Bundesanstalt. A dedicated correction algorithm automatically corrects the systematic errors of the components and leads to an uncertainty on the order of 40 /VA of the active power for voltages up to 220 kV/ and up to 2 kA at any power factor. It is intended to use this standard for calibrating reference measuring systems of accredited laboratories offering calibration service for calibrating industrial power transformer test systems or for manufacturers of such industrial measurement systems. Autors: Enrico Mohns;Peter Räther;Henrik Badura; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Sep 2017, volume: 66, issue:9, pages: 2225 - 2232 Publisher: IEEE
» An Accurate Semianalytical Waveform Model for Mispointed SAR Interferometric Altimeters
 Abstract:Synthetic aperture radar (SAR) altimeters reduce the along-track footprint size exploiting the coherence of the transmitted pulses and achieve at the same time a noise reduction. Consequently, a large effort has been aimed at the formulation of theoretical models that apply to SAR altimeters, in order to fully exploit the improvement in spatial resolution obtained from the along-track aperture synthesis. This letter presents a novel semianalytical waveform model for SAR interferometric altimeters that preserves high accuracy even in the presence of mispointing. Starting from the waveform model proposed by Wingham et al. that provides a unified formulation for pulse-limited and SAR interferometric altimeters which can only be computed numerically, here, we describe a semianalytical approximation for small variations of the mispointing angles around an arbitrary combination of pitch and roll angles . The proposed semianalytical waveform model allows to reduce the high dimensionality of the model proposed by Wingham et al. and it has been proven to be accurate for variations of mispointing angles up to 0.4 deg around the . The performance of the proposed formulation has been evaluated on simulated data from Sentinel-6 configuration and on real data from CryoSat-2 SARin acquisitions over ocean. Autors: Lisa Recchia;Michele Scagliola;Davide Giudici;Mieke Kuschnerus; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1537 - 1541 Publisher: IEEE
» An Adaptive Parallel Algorithm for Computing Connected Components
 Abstract:We present an efficient distributed memory parallel algorithm for computing connected components in undirected graphs based on Shiloach-Vishkin’s PRAM approach. We discuss multiple optimization techniques that reduce communication volume as well as load-balance the algorithm. We also note that the efficiency of the parallel graph connectivity algorithm depends on the underlying graph topology. Particularly for short diameter graph components, we observe that parallel Breadth First Search (BFS) method offers better performance. However, running parallel BFS is not efficient for computing large diameter components or large number of small components. To address this challenge, we employ a heuristic that allows the algorithm to quickly predict the type of the network by computing the degree distribution and follow the optimal hybrid route. Using large graphs with diverse topologies from domains including metagenomics, web crawl, social graph and road networks, we show that our hybrid implementation is efficient and scalable for each of the graph types. Our approach achieves a runtime of 215 seconds using 32 K cores of Cray XC30 for a metagenomic graph with over 50 billion edges. When compared against the previous state-of-the-art method, we see performance improvements up to 24 . Autors: Chirag Jain;Patrick Flick;Tony Pan;Oded Green;Srinivas Aluru; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Sep 2017, volume: 28, issue:9, pages: 2428 - 2439 Publisher: IEEE
» An Advanced Multiscale Edge Detector Based on Gabor Filters for SAR Imagery
 Abstract:The ratio of averages is a robust edge detector which provides the property of constant false alarm rate for synthetic aperture radar (SAR) imagery. However, the rectangular window used in the calculation of local mean may cause numerous false maxima. The size of the processing window also has a significant effect on the detection performance, but it is difficult to determine the optimum window size. In this letter, we first propose a new ratio-based detector that is constructed by the Gabor odd filter. The scale of the proposed detector is related to the size of the processing window. Then, edge strength maps extracted by multiscale detectors are combined using an edge tracking algorithm to form a final response. We used the receiver operating characteristic curves to evaluate the performance of the proposed detector. The experimental results on simulated and real-world SAR images show that the proposed multiscale edge detector yields an accurate and consecutive edge response. Autors: Yuming Xiang;Feng Wang;Ling Wan;Hongjian You; Appeared in: IEEE Geoscience and Remote Sensing Letters Publication date: Sep 2017, volume: 14, issue:9, pages: 1522 - 1526 Publisher: IEEE
» An Approach to Identifying Phenomena Accompanying Micro and Nanoparticles in Contact With Irregular Vessel Walls
 Abstract:The objective of this paper is to present the method for determining the nature and values of the forces needed to set micro and nanoparticles sitting immobile at the blood vessel wall in motion. The problem was tackled in two ways. Microparticles were examined as objects coming into contact with the wall with the actual large arteriole-type vessel structure. The forces acting on microparticles 10, 30, and in diameter were determined: drag force , lift force , electrostatic force , and gravity force . Fluid-structure interaction analysis was used to research the problem. However, nanoparticles were examined as objects coming into contact with the endothelial surface layer (ESL). Resistance forces during the movement of nanoparticles 20, 50, and 100 nm in diameter in the ESL were determined. The same was done for aggregates of nanoparticles 50 nm in diameter. Local irregularities in wall surface are important for microparticles. Small irregularities with the small values of electrostatic force can effectively stop the particle. In the case of nanoparticles, the key is the interaction of the particle with ESL. The research methodology presented can be used to better understand the particle-blood vessel wall interaction phenomena, leading to a more informed particle movement control. The new application of known calculation methods presented in this paper can be successfully used as an additional tool that simplifies planning and design of strategies for drug delivery by me- ns of micro and nanoparticles. Autors: K. Talaśka;A. Ferreira; Appeared in: IEEE Transactions on NanoBioscience Publication date: Sep 2017, volume: 16, issue:6, pages: 463 - 475 Publisher: IEEE
» An Approximate Dynamic Programming Approach to Multiagent Persistent Monitoring in Stochastic Environments With Temporal Logic Constraints
 Abstract:We consider the problem of generating control policies for a team of robots moving in a stochastic environment. The team is required to achieve an optimal surveillance mission, in which a certain “optimizing proposition” needs to be satisfied infinitely often. In addition, a correctness requirement expressed as a temporal logic formula is imposed. By modeling the robots as game transition systems and the environmental elements as Markov chains, the problem reduces to finding an optimal control policy for a Markov decision process, which also satisfies a temporal logic specification. The existing approaches based on dynamic programming are computationally intensive, thus not feasible for large environments and/or large numbers of robots. We propose an approximate dynamic programming (ADP) framework to obtain suboptimal policies with reduced computational complexity. Specifically, we choose a set of basis functions to approximate the optimal costs and find the best approximation through the least-squares method. We also propose a simulation-based ADP approach to further reduce the computational complexity by employing low-dimensional calculations and simulation samples. Autors: Kun Deng;Yushan Chen;Calin Belta; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4549 - 4563 Publisher: IEEE
» An Approximate Transfer Function Model of Two Serially Connected Heterogeneous Transmission Lines
 Abstract:This brief presents an approximate transfer function model of two heterogeneous transmission lines connected in series. The proposed model is simple, intuitive, and can accurately describe the frequency response of various serially connected heterogeneous interconnects which satisfy a validity condition. The exact error of the proposed model is also provided. According to our analysis, the validity condition can be clearly interpreted by the propagation and the reflection waves. The accuracy of the proposed model is verified by comparing the calculated transfer function of LC-dominant off-chip and RC-dominant on-chip examples against SPICE simulation results. In these verifications, the maximum errors between calculation and simulation are, respectively, 2.58% and 3.32% for off-chip and on-chip examples. The computation time is also reduced about 29.76 and 289.07 times compared with a single-channel model and the SPICE -element model. With the proposed model, designers can easily understand the channel responses of diverse serially connected heterogeneous interconnects. Autors: Jaeyoung Seo;Minsoo Choi;Sanquan Song;Jae-Yoon Sim;Hong-June Park;Byungsub Kim; Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs Publication date: Sep 2017, volume: 64, issue:9, pages: 1067 - 1071 Publisher: IEEE
» An Architecture for Capturing the Nonlinear Distortion of Analog Self-Interference Cancellers in Full-Duplex Radios
 Abstract:Analog self-interference (SI) cancellation is a key process to enable full-duplex wireless communications, which generates a cancelling signal (a copy of the SI) at the local receiver and subtracts from the received signal to cancel the SI imposed by the local transmitter. However, due to the inherent nonlinearities of analog canceller (AC), the SI cancellation performance is often restricted by introducing extra nonlinear distortion to the receiver. In this letter, an observation architecture is proposed to capture the AC nonlinear distortion by deploying an auxiliary chain identical to the AC and a linear cancellation approach. The captured nonlinear distortion could be used as a reference in the digital domain to mitigate the AC-induced nonlinear interference at the receiver. Experiments verify that the proposed architecture is capable of capturing the weak AC-induced distortion and suppressing it to close the receiver noise floor. Autors: Ying Liu;Wanzhi Ma;Xin Quan;Wensheng Pan;Kai Kang;Youxi Tang; Appeared in: IEEE Microwave and Wireless Components Letters Publication date: Sep 2017, volume: 27, issue:9, pages: 845 - 847 Publisher: IEEE
» An Automatic Algorithm to Retrieve Wave Height From X-Band Marine Radar Image Sequence
 Abstract:A new method is proposed to retrieve wave height from an X-band marine radar image sequence, without external measurements for reference. The X-band marine radar image sequence is first decomposed by empirical orthogonal function (EOF), and then the sea surface height profile is reconstructed and scaled from the first EOF mode. The radial profiles that are close to the peak wave direction are used to extract the zero-crossing wave periods and relative wave heights. The spectral width parameter is deduced from the histogram of a dimensionless wave period. Based on a joint probability distribution function (pdf) of a dimensionless wave period and wave height, the theoretical pdf of the wave height is derived. A shape parameter is defined for the theoretical pdf and the histogram of the relative wave heights, and then the calibration coefficient is estimated. The method is validated by comparing the significant wave heights retrieved from two different X-band marine radar systems with those measured by buoy; the correlation coefficient, the root-mean-square error, and the bias between them are 0.78, 0.51 m, and −0.19 m for HH polarization, while they are 0.77, 0.51 m, and 0.19 m for VV polarization, respectively. The sources of error of the method are discussed. Autors: Zhongbiao Chen;Yijun He;Biao Zhang; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 5084 - 5092 Publisher: IEEE
» An Auxiliary Particle Filtering Algorithm With Inequality Constraints
 Abstract:For nonlinear non-Gaussian stochastic dynamic systems with inequality state constraints, this technical note presents an efficient particle filtering algorithm, constrained auxiliary particle filtering algorithm. To deal with the state constraints, the proposed algorithm probabilistically selects particles such that those particles far away from the feasible area are less likely to propagate into the next time step. To improve on the sampling efficiency in the presence of inequality constraints, it uses a highly effective method to perform a series of constrained optimization so that the importance distributions are constructed efficiently based on the state constraints. The caused approximation errors are corrected using the importance sampling method. This ensures that the obtained particles constitute a representative sample of the true posterior distribution. A simulation study on vehicle tracking is used to illustrate the proposed approach. Autors: Baibing Li;Cunjia Liu;Wen-Hua Chen; Appeared in: IEEE Transactions on Automatic Control Publication date: Sep 2017, volume: 62, issue:9, pages: 4639 - 4646 Publisher: IEEE
» An Easy and Efficient Method for Synthesizing Two-Dimensional Finite Impulse Response Filters with Improved Selectivity [Tips & Tricks]
 Abstract:It is hard to imagine what the world would look like without the modern technologies using digital signal processing. The developments in this technical field provide an opportunity for building technical devices that implement mathematical methods unattainable by analog technology. Many modern technical devices work with two-dimensional (2-D) signals in a process called digital image processing, and 2-D digital finite impulse response (FIR) filters are basic technical tools in image processing. FIR filters are extensively used in digital television, radio astronomy, radio location, biomedicine, and so on. Autors: Peter S. Apostolov;Borislav P. Yurukov;Alexey K. Stefanov; Appeared in: IEEE Signal Processing Magazine Publication date: Sep 2017, volume: 34, issue:5, pages: 180 - 183 Publisher: IEEE
» An Economical and SLO-Guaranteed Cloud Storage Service Across Multiple Cloud Service Providers
 Abstract:It is important for cloud service brokers to provide a multi-cloud storage service to minimize their payment cost to cloud service providers (CSPs) while providing service level objective (SLO) guarantee to their customers. Many multi-cloud storage services have been proposed or payment cost minimization or SLO guarantee. However, no previous works fully leverage the current cloud pricing policies (such as resource reservation pricing) to reduce the payment cost. Also, few works achieve both cost minimization and SLO guarantee. In this paper, we propose a multi-cloud Economical and SLO-guaranteed Storage Service (), which determines data allocation and resource reservation schedules with payment cost minimization and SLO guarantee. incorporates (1) a coordinated data allocation and resource reservation method, which allocates each data item to a datacenter and determines the resource reservation amount on datacenters by leveraging all the pricing policies; (2) a genetic algorithm based data allocation adjustment method, which reduce data Get/Put rate variance in each datacenter to maximize the reservation benefit. We also propose several algorithms to enhance the cost efficient and SLO guarantee performance of including i) dynamic request redirection, ii) grouped Gets for cost reduction, iii) lazy update for cost-efficient Puts, and iv) concurrent requests for rigid Get SLO guarantee. Our trace-driven experiments on a supercomputing cluster and on real clouds (i.e., Amazon S3, Windo- s Azure Storage and Google Cloud Storage) show the superior performance of in payment cost minimization and SLO guarantee in comparison with previous methods. Autors: Guoxin Liu;Haiying Shen;Haoyu Wang; Appeared in: IEEE Transactions on Parallel and Distributed Systems Publication date: Sep 2017, volume: 28, issue:9, pages: 2440 - 2453 Publisher: IEEE
» An Effective Fuzzy Feature Selection and Prediction Method for Modeling Tidal Current: A Case of Persian Gulf
 Abstract:This paper develops a new two-stage approach for accurate modeling and prediction of tidal current. The proposed method makes use of a novel fuzzy feature selection to extract the most preferable features from the tidal current speed and direction data set. The selected features are further used to train a support vector regression for accurate prediction. The setting parameters of the proposed model are trained by a new optimization algorithm based on the harmony search algorithm to get to the most optimal training targets. The proposed optimization algorithm makes use of the crossover and mutation operators from genetic algorithm to escape from the local optima and find the global solutions. Experimental tidal data from Persian Gulf, Iran, are used to assess the accuracy and performance of the proposed model. The results show the appropriate performance and high precision of the proposed model in comparison with other famous methods. Autors: Behnaz Papari;Chris S. Edrington;Farzaneh Kavousi-Fard; Appeared in: IEEE Transactions on Geoscience and Remote Sensing Publication date: Sep 2017, volume: 55, issue:9, pages: 4956 - 4961 Publisher: IEEE
» An Efficient Autocalibration Method for Triaxial Accelerometer
 Abstract:This paper investigates the autocalibration of microelectromechanical systems (MEMS) triaxial accelerometer (TA) based on experimental design (DoE). First, for a special 6-parameter second-degree model, a six-point experimental scheme is proposed, and its G-optimality has been proven based on optimal DoE. Then, a new linearization approach is introduced, by which the TA model for autocalibration can be simplified as the expected second-degree form so that the proposed optimal experimental scheme can be applied. To reliably estimate the model parameter, a convergence-guaranteed iterative algorithm is also proposed, which can significantly reduce the bias caused by linearization. Thereafter, the effectiveness and robustness of the proposed approach have been demonstrated by simulation. Finally, the proposed calibration method has been experimentally verified using two typical types of MEMS TA, and desired experimental results effectively demonstrate the efficiency and accuracy of the proposed calibration approach. Autors: Lin Ye;Ying Guo;Steven W. Su; Appeared in: IEEE Transactions on Instrumentation and Measurement Publication date: Sep 2017, volume: 66, issue:9, pages: 2380 - 2390 Publisher: IEEE
» An Efficient Fast Algorithm for Accelerating the Time-Domain Integral Equation Discontinuous Galerkin Method
 Abstract:An efficient fast algorithm for accelerating the time-domain integral equation discontinuous Galerkin (TDIEDG) method for analyzing the transient scattering from electrically large complex objects is proposed. The TDIEDG is discretized using the monopolar Rao–Wilton–Glisson (RWG) function and shifted Lagrange polynomial function in spatial and time domain, respectively. The final system of equations can be solved iteratively using the classical marching-on-in-time scheme. Taking advantage of the approximate evaluation of the vector and scalar potential terms combined with the Taylor series expansion of the transient far field, the computational burden of the TDIEDG solver has been significantly reduced. In addition, it is flexible and convenient to analyze object with nonconformal discretization due to the employment of the monopolar RWG functions. Autors: G. S. Cheng;D. Z. Ding;R. S. Chen; Appeared in: IEEE Transactions on Antennas and Propagation Publication date: Sep 2017, volume: 65, issue:9, pages: 4919 - 4924 Publisher: IEEE
» An Efficient Heterogeneous Memristive xnor for In-Memory Computing
 Abstract:Resistive RAM (RRAM) technologies are gaining importance due to their appealing characteristics, which include non-volatility, small form factor, low power consumption, and ability to perform logic operations in memory. These characteristics make RRAM highly suited for Internet of Things devices and similarly resource-constrained systems. This paper proposes a novel memristor-based xnor gate that enables the execution of xnor/xor function in the memristive crossbar memory. The proposed two-input xnor gate requires two steps to perform the xnor function. The design of the circuit utilizes bipolar and unipolar memristors and permits cascading by only adding an extra step and one computing memristor. To the best of our knowledge, this is the first native stateful xnor logic implementation. Spice simulations have been used to verify the functionality of the proposed circuit. This includes benchmarking the proposed design against the state-of-the-art stateful memristor-based logic circuits. The results for implementing three-input xor using the proposed circuit demonstrate efficient performance in terms of energy, latency, and area. The gate shows 56% saving in energy, 54% less number of steps (latency), and 50% less number of computing MR (area) compared with the state-of-the-art stateful xor/xnor implementations. Autors: Muath Abu Lebdeh;Heba Abunahla;Baker Mohammad;Mahmoud Al-Qutayri; Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers Publication date: Sep 2017, volume: 64, issue:9, pages: 2427 - 2437 Publisher: IEEE
» An Efficient Precoder Size for Interference Alignment of the $K$ -User Interference Channel
 Abstract:In this letter, we explore interference alignment for the -user single input single output interference channel with more efficient precoder sizes and lower sensitivity to channel state information at transmitters (CSIT). The main idea in this letter is to divide transmission time into some distinct blocks and select a subset of transmitters and receivers for signaling in each block. We show that our method can achieve more sum degrees-of-freedom compared with other schemes in the limited number of channel extensions. Furthermore, our method needs no full CSIT to be applicable which can be considered as another advantage of this letter. Autors: Milad Johnny;Mohammad Reza Aref; Appeared in: IEEE Communications Letters Publication date: Sep 2017, volume: 21, issue:9, pages: 1941 - 1944 Publisher: IEEE
» An Emergency-Demand-Response Based Under Speed Load Shedding Scheme to Improve Short-Term Voltage Stability
 Abstract:The dynamics of load, especially induction motors, are the driving force for short-term voltage stability (STVS) problems. In this paper, the equivalent rotation speed of motors is identified online and its recovery time is estimated next to realize an emergency-demand-response (EDR) based under speed load shedding (USLS) scheme to improve STVS. The proposed scheme consists of an EDR program and two regular stages (RSs). In the EDR program, contracted load is used as a fast-response resource rather than the last defense. The estimated recovery time (ERT) is used as the triggering signal for the EDR program. In the RSs, the amount of load to be shed at each bus is determined according to the assigned weights based on ERTs. Case studies on a practical power system in China Southern Power Grid have validated the performance of the proposed USLS scheme under various contingency scenarios. The utilization of EDR resources and the adaptive distribution of shedding amount in RSs guarantee faster voltage recovery. Therefore, USLS offers a new and more effective approach compared with existing under voltage load shedding to improve STVS. Autors: Yipeng Dong;Xiaorong Xie;Ke Wang;Baorong Zhou;Qirong Jiang; Appeared in: IEEE Transactions on Power Systems Publication date: Sep 2017, volume: 32, issue:5, pages: 3726 - 3735 Publisher: IEEE

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