Electrical and Electronics Engineering publications abstract of: 07-2017 sorted by title, page: 14

» Single Uniprior Index Coding With Min–Max Probability of Error Over Fading Channels
Abstract:
An index coding scheme in which the source (transmitter) transmits symbols over a wireless fading channel is considered. Index codes with the transmitter using minimum number of transmissions are known as optimal index codes. Different optimal index codes give different performances in terms of probability of error in a fading environment, and this also varies from receiver to receiver. In this paper, we deal with optimal index codes, which minimizes the maximum probability of error among all the receivers. We identify a criterion for optimal index codes that minimizes the maximum probability of error among all the receivers. For a special class of index coding problems, we give an algorithm to identify optimal index codes which minimize the maximum error probability. We illustrate our techniques and claims with simulation results leading to conclude that a careful choice among the optimal index codes will give a considerable gain in fading channels.
Autors: Anoop Thomas;Kavitha Radhakumar;Chandramouli Attada;B. Sundar Rajan;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2017, volume: 66, issue:7, pages: 6050 - 6059
Publisher: IEEE
 
» Single/Multiple Integral Inequalities With Applications to Stability Analysis of Time-Delay Systems
Abstract:
This technical note is concerned with the problem of stability analysis for time-delay systems. A new series of integral inequalities to bound a single integral term is presented by introducing some free matrices, which produces tighter bounds than some existing ones. Similarly, based on orthogonal polynomials defined in integral inner spaces, new series of multiple integral inequalities are presented as well, which include the existing double ones. To show the effectiveness of the proposed inequalities, their applications to stability analysis of systems with discrete and distributed delays are provided with numerical examples.
Autors: Jun Chen;Shengyuan Xu;Baoyong Zhang;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2017, volume: 62, issue:7, pages: 3488 - 3493
Publisher: IEEE
 
» Size and Weight Reduction of an In-Wheel Axial-Gap Motor Using Ferrite Permanent Magnets for Electric Commuter Cars
Abstract:
In-wheel type permanent-magnet synchronous motors for electric commuter cars are required to be compact and light to use limited wheel space effectively and reduce unspringing weight. Therefore, our previous papers presented a low-cost in-wheel axial-gap motor that uses ferrite permanent magnets. This motor adopted an open slot structure to reduce production costs. However, to achieve further size and weight reduction, we examine here in detail the adoption of a semiclosed slot structure instead of an open slot structure. Experimental results show that the semiclosed slot structure is effective in realizing size and weight reduction.
Autors: Tomohira Takahashi;Masatsugu Takemoto;Satoshi Ogasawara;Wataru Hino;Kenichi Takezaki;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2017, volume: 53, issue:4, pages: 3927 - 3935
Publisher: IEEE
 
» Size Distribution Control of Copper Nanoparticle: Effect of Precursor Morphology
Abstract:
In the liquid phase synthesis of metallic nanoparticles by electroless deposition, the morphology of product is strongly dependent on numerous synthesis conditions; for example, the type or quantity of solvent, precursor, reductant, and dispersant species. In this work, the influence of the surface area of precursor on the size distribution of synthesized nanoparticles was investigated using a kinetic evaluation by quartz crystal microbalance (QCM) measurement. We clarified the correlation between the morphology of product and the deposition behavior such as termination point and deposition rate derived by QCM measurement. We also measured the immersion potential of the reaction solution, and found that the nucleation and growth of Cu nanoparticles were supposed to proceed with the reduction of Cu(II) ion to Cu as long as the Cu(II) sufficiently exist in the solution. Therefore, the saturation of deposition amount on QCM indicated the consumption of precursors. By this estimation, we demonstrated the size distribution was predictable from QCM measurement, and it was controllable by regulating the morphology of precursor.
Autors: Shohei Shiomi;Tomoki Maruoka;Hideaki Minami;Jun-ichiro Kadono;Yasumasa Kikuuchi;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jul 2017, volume: 16, issue:4, pages: 588 - 594
Publisher: IEEE
 
» Skewed Straintronic Magnetotunneling-Junction-Based Ternary Content-Addressable Memory—Part I
Abstract:
This paper presents a ternary content-addressable memory (TCAM) cell based on a skewed straintronic magnetotunneling junction (MTJ) switch. A straintronic magnetotunneling junction (s-MTJ) is a three-terminal switch, where the resistance between two of the terminals switches when a potential is applied to the third (gate) terminal that induces strain in the magnetostrictive free-layer. An s-MTJ is a highly energy-efficient switch that would dissipate only ~aJ of energy during switching. This paper discusses a novel variant of s-MTJ, namely skewed s-MTJ (ss-MTJ), where the MTJ switching can be controlled by two gate terminals. The current through an ss-MTJ is minimum when the potentials at the first and second gate terminals ( and , respectively) obey the relation . Here, is a fixed voltage (“offset voltage”). Current in an ss-MTJ increases steeply when and deviate from the above “match” condition. This unconventional – characteristic of an ss-MTJ is exploited to design a non-Boolean TCAM cell based on just one transistor, one trench capacitor, and one ss-MTJ. We also discuss search and write operations in the ss-MTJ-TCAM cell, and show that the cell requires very small voltages to operate because - f the unique – characteristics of the ss-MTJ.
Autors: Susmita Dey Manasi;Md Mamun Al-Rashid;Jayasimha Atulasimha;Supriyo Bandyopadhyay;Amit Ranjan Trivedi;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jul 2017, volume: 64, issue:7, pages: 2835 - 2841
Publisher: IEEE
 
» Skybridge-3D-CMOS: A Fine-Grained 3D CMOS Integrated Circuit Technology
Abstract:
Parallel and monolithic three-dimensional (3-D) integration directions realize 3-D integrated circuits (ICs) by utilizing layer-by-layer implementations, with each functional layer being composed in 2-D. In contrast, vertically composed 3-D CMOS has eluded us likely due to the seemingly insurmountable requirement of highly customized complex routing and regional 3-D doping to form and connect CMOS pull-up and pull-down networks in 3-D. In the current layer-by-layer directions, routing can be worse than 2D CMOS because of the limited pin access. In this paper, we propose Skybridge-3D-CMOS (S3DC), an IC fabric that shows for the first time a pathway to achieve fine-grained static CMOS circuit implementations using the vertical direction while also solving 3-D routability. It employs a new fabric assembly scheme based on predoped vertical nanowire bundles. It implements circuits in and across nanowires. It utilizes unique connectivity features to achieve CMOS connectivity in 3-D with excellent routability. As compared to the usually severely congested monolithic 3-D implementations, S3DC eliminates the routing congestions in all benchmarks studied. Further results, for the implemented benchmarks, show 56–77% reductions in power consumption, 4X–90X increases in density, and 20% loss to 9% benefit in best operating frequencies compared with the transistor-level monolithic 3-D technology.
Autors: Mingyu Li;Jiajun Shi;Mostafizur Rahman;Santosh Khasanvis;Sachin Bhat;Csaba Andras Moritz;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jul 2017, volume: 16, issue:4, pages: 639 - 652
Publisher: IEEE
 
» Sliding Mode Observer-Based FTC for Markovian Jump Systems With Actuator and Sensor Faults
Abstract:
This paper addresses the stabilization problem for nonlinear Markovian jump systems (MJS) with output disturbances, actuator and sensor faults simultaneously. This kind of plants are common in practical systems, such as mobile manipulators with switching joints. In this paper, a sliding mode observer design scheme is proposed for a new descriptor augmented plant. By employing the developed observer, the effects of actuator and sensor faults can be eliminated. It is shown that the stabilization of the overall closed-loop plant can be guaranteed by the proposed fault tolerant control (FTC) scheme. Finally, an example concerning mobile manipulators with Markovian switching joints is presented to show the effectiveness and applicability of the theoretical results.
Autors: Shen Yin;Hongyan Yang;Okyay Kaynak;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2017, volume: 62, issue:7, pages: 3551 - 3558
Publisher: IEEE
 
» Smartphone-Based Real Time Vehicle Tracking in Indoor Parking Structures
Abstract:
Although location awareness and turn-by-turn instructions are prevalent outdoors due to GPS, we are back into the darkness in uninstrumented indoor environments such as underground parking structures. We get confused, disoriented when driving in these mazes, and frequently forget where we parked, ending up circling back and forth upon return. In this paper, we propose VeTrack, asmartphone-only system that tracks the vehicle’s location in real time using the phone’s inertial sensors. It does not require any environment instrumentation or cloud backend. It uses a novel “shadow” trajectory tracing method to accurately estimate phone’s and vehicle’s orientations despite their arbitrary poses and frequent disturbances. We develop algorithms in a Sequential Monte Carlo framework to represent vehicle states probabilistically, and harness constraints by the garage map and detected landmarks to robustly infer the vehicle location. We also find landmark (e.g., speed bumps, turns) recognition methods reliable against noises, disturbances from bumpy rides, and even hand-held movements. We implement a highly efficient prototype and conduct extensive experiments in multiple parking structures of different sizes and structures, and collect data with multiple vehicles and drivers. We find that VeTrack can estimate the vehicle’s real time location with almost negligible latency, with error of parking spaces at the 80th percentile.
Autors: Ruipeng Gao;Mingmin Zhao;Tao Ye;Fan Ye;Yizhou Wang;Guojie Luo;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jul 2017, volume: 16, issue:7, pages: 2023 - 2036
Publisher: IEEE
 
» Smooth Mobility and Link Reliability-Based Optimized Link State Routing Scheme for MANETs
Abstract:
Link reliability metrics are of great significance in routing design for mobile ad hoc networks (MANETs). In this letter, we propose a novel optimized link state routing (OLSR) scheme named smooth mobility and link reliability-based OLSR (SMLR_OLSR). It is implemented on the basis of a prudentially designed semi-Markov smooth and complexity restricted mobility model, which complies sufficiently with realistic node behaviors and is typically used for reliability-enhanced multi-point relay (MPR) selection in SMLR_OLSR. Simulation results show that the proposed scheme ensures an accurate performance analysis, and can achieve longer MPR lifetime and less control overhead.
Autors: Zhinan Li;Yinfeng Wu;
Appeared in: IEEE Communications Letters
Publication date: Jul 2017, volume: 21, issue:7, pages: 1529 - 1532
Publisher: IEEE
 
» Snowmelt Pattern Over High-Mountain Asia Detected From Active and Passive Microwave Remote Sensing
Abstract:
The snow in high-mountain Asia (HMA) is of great importance, as it is very sensitive to the climate change. Air temperature and precipitation shifts/increases will be reflected in the timing of snowmelt onset. In this letter, a new algorithm is proposed to determine the snowmelt onset date from active and passive microwave remote sensing data, and the spatial and temporal pattern of snowmelt onset in HMA is studied using active and passive microwave remote sensing for the first time. Over 35 years of passive microwave data and ten years of active microwave data are used to derive the melt onset date in HMA. The active microwave data has 4.5-km resolution so that more detailed spatial pattern of snowmelt onset date can be derived compared to the 25-km resolution passive microwave data. Under climate change background, time series analyses of the snowmelt onset date in HMA are conducted to study the snowmelt onset time changes in recent 35 years. This letter provides an objective evidence of climate change impact on the cryospheric system. Time series analysis shows that the snowmelt onset date is becoming earlier in HMA region during 1988–2015, except the Karakorum Mountains and part of the western Kunlun Mountains. Mean air temperature is compared with the time series snowmelt onset date and the results show that there is strong correlation between mean air temperature and average snowmelt onset date. A 4.5 days/degree rate of snowmelt onset date advancing is found.
Autors: Chuan Xiong;Jiancheng Shi;Yurong Cui;Bin Peng;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jul 2017, volume: 14, issue:7, pages: 1096 - 1100
Publisher: IEEE
 
» Software-Defined Underwater Acoustic Modems: Historical Review and the NILUS Approach
Abstract:
Flexible/adaptive acoustic modems that are reprogrammable/reconfigurable at all layers of the communication stack, either by a user or by means of autonomous decisions, are considered as an important enabler for interoperability and cognitive networking in the underwater domain. In this paper, we review the existing literature on software-defined acoustic modems (SDAMs) for underwater communications and networking, considering past and ongoing academic efforts, as well as industrial developments and European collaborations centered on software-defined modem structures and functionalities. We then zoom in on relevant R&D efforts currently taking place in a defense cooperation between The Netherlands and Norway, targeting the design of a software-defined modem for the NILUS MK 2 sensor node. This modem is built using general-purpose (GP) computing architectures running open-source operating system and tools, thereby making a further step toward software-defined open-architecture underwater acoustic modems. The first field tests of the NILUS MK 2 node in multihop underwater acoustic networks are presented, showing satisfactory performance in shallow and open waters.
Autors: Henry S. Dol;Paolo Casari;Timo van der Zwan;Roald Otnes;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jul 2017, volume: 42, issue:3, pages: 722 - 737
Publisher: IEEE
 
» Solid-State-Transformer-Interfaced Permanent Magnet Wind Turbine Distributed Generation System With Power Management Functions
Abstract:
The higher penetration of wind energy poses increasing demand for grid support and power management functions of a wind energy conversion system (WECS). This paper investigates a medium-voltage solid-state transformer (SST)-interfaced permanent magnet synchronous generator system with integrated active power management and reactive power compensation functions. Specifically, a WECS consisting of wind turbines, SSTs, and dc loads is presented. In addition, a distributed power management algorithm is proposed for a dc network with local wind turbine controls incorporated to achieve a self-contained power-balanced condition without the need for energy storage or communication devices. Scenarios considered include the grid-connected mode, the islanding mode, and the mode transitions. Simulation results are provided to verify the effectiveness of the proposed strategy. Additionally, the concept is experimentally verified using a scaled-down laboratory prototype.
Autors: Rui Gao;Xu She;Iqbal Husain;Alex Q. Huang;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2017, volume: 53, issue:4, pages: 3849 - 3861
Publisher: IEEE
 
» Some New Results on Integral-Type Backstepping Method for a Control Problem Governed by a Linear Heat Equation
Abstract:
It is well known in the literature that the design of stabilization controllers for control systems governed by linear heat equations can be achieved by applying the integral-type backstepping transformation. In this paper, its focus is to establish three new results. First, by controllability theory, we show that the choice of kernels is unique in the context of integral-type backstepping transformation. Next, we show that the forward transformation and inverse transformation in the integral-type backstepping method are mutual transformation pair via solving an easily solvable PDE. With this result, the need of finding explicit solutions of kernel equations can be avoided. Finally, by constructing a corresponding LQ problem, we show that the optimal control of the LQ problem is exactly the stabilization control of the heat equation obtained by the integral-type backstepping method.
Autors: Zhongcheng Zhou;Changjun Yu;Kok Lay Teo;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2017, volume: 62, issue:7, pages: 3640 - 3645
Publisher: IEEE
 
» Source Localization With Multiple Hydrophone Arrays via Matched-Field Processing
Abstract:
This paper considers approaches to combining information from multiple arrays in matched-field processing (MFP) for underwater acoustic source localization. The standard approach is to apply conventional MFP for each array independently, and sum the resulting Bartlett ambiguity surfaces computed for each array; this approach assumes that individual arrays comprise calibrated sensors which are synchronized in time. However, if the relative calibration and/or time synchronization is known between some or all arrays, more informative multiple-array processors can be derived using maximum-likelihood methods. If the relative calibration between arrays is known, the observed variation in received signal amplitude between arrays provides additional information for matched-field localization which is absent in the standard processor. If synchronization is known between arrays, phase variations provide additional localization information. Multiple-array processors accounting for different levels of interarray information are derived and evaluated in terms of the probability of correct localization from Monte Carlo analyses for a range of signal-to-noise ratios and the number of frequencies for simulated shallow-water scenarios with multiple horizontal and/or vertical arrays. The analysis indicates that, dependent on array configurations, significant improvements in source localization performance can be achieved when including relative amplitude and/or phase information in the multiple-array processor. The improvement is reduced by environmental and array (calibration and synchronization) mismatch; however, this degradation can be partially mitigated by including additional frequencies in the processing.
Autors: Dag Tollefsen;Stan E. Dosso;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jul 2017, volume: 42, issue:3, pages: 654 - 662
Publisher: IEEE
 
» Space-Time Network Coding With Multiple AF Relays Over Nakagami- $m$ Fading Channels
Abstract:
This paper first analyzes the symbol error rate (SER) performance of the space-time network coding (STNC) over independent but not necessarily identically distributed (i.n.i.d) Nakagami- fading channels, where multiple sources transmit information symbols to a destination through multiple helping amplify-and-forward (AF) relays. The exact expressions of the overall end-to-end received signal-to-noise ratio (SNR) via multiple STNC-AF relays and its moment generating function (MGF) are derived. Based on these results, the closed-form expression of STNC-AF for the SER with -ary phase-shift keying and -ary quadrature-amplitude modulation (QAM) modulations are then presented by adopting the unified MGF method. Furthermore, an approximate SER expression with low computational complexity is also given. In order to observe the performance limit, the diversity order and the nonorthogonality of STNC codes are discussed. Simulation results demonstrate our analytical results and it is illustrated that the diversity order of the STNC with multiple AF relay nodes is a sum function of the fading index of the direct link and the minimal fading indices of the multiple two-hop links.
Autors: Yu Zhang;Ke Xiong;Pingyi Fan;Hong-Chuan Yang;Xianwei Zhou;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2017, volume: 66, issue:7, pages: 6026 - 6036
Publisher: IEEE
 
» Spacer Design Guidelines for Nanowire FETs From Gate-Induced Drain Leakage Perspective
Abstract:
In this paper, we study for the first time the impact of the design of gate sidewall spacer on the gate-induced drain leakage (GIDL) of: 1) the conventional nanowire (NW) FETs and 2) NWFETs with a gate–source/drain extension underlap. We demonstrate that the inclusion of a high- spacer over the source/drain extension region in the conventional NWFETs results in a suppressed lateral band-to-band tunneling (L-BTBT) GIDL. Furthermore, we also show that a gate–source/drain extension underlap architecture in NWFETs not only reduces the transverse BTBT GIDL but also mitigates the L-BTBT. However, the inclusion of a high- spacer in the underlapped NWFET leads to an enhanced L-BTBT and an increased OFF-state current compared with the underlapped NWFET with air spacer unlike FinFETs. In addition, we also study the impact of nanowire diameter and underlap length on L-BTBT GIDL of NWFETs. Furthermore, we demonstrate that the inclusion of the high- spacer increases the intrinsic delay owing to an increased fringe capacitance. Therefore, we provide the necessary design guidelines for performance optimization of NWFETs in the sub-10-nm regime.
Autors: Shubham Sahay;Mamidala Jagadesh Kumar;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Jul 2017, volume: 64, issue:7, pages: 3007 - 3015
Publisher: IEEE
 
» Sparse Multigraph Embedding for Multimodal Feature Representation
Abstract:
Data fusion is used to integrate features from heterogenous data sources into a consistent and accurate representation for certain learning tasks. As an effective technique for data fusion, unsupervised multimodal feature representation aims to learn discriminative features, indicating the improvement of classification and clustering performance of learning algorithms. However, it is a challenging issue since varying modality favors different structural learning. In this paper, we propose an efficient feature learning method to represent multimodal images as a sparse multigraph structure embedding problem. First, an effective algorithm is proposed to learn a sparse multigraph construction from multimodal data, where each modality corresponds to one regularized graph structure. Second, incorporating the learned multigraph structure, the feature learning problem for multimodal images is formulated as a form of matrix factorization. An efficient corresponding algorithm is developed to optimize the problem and its convergence is also proved. Finally, the proposed method is compared with several state-of-the-art single-modal and multimodal feature learning techniques in eight publicly available face image datasets. Comprehensive experimental results demonstrate that the proposed method outperforms the existing ones in terms of clustering performance for all tested datasets.
Autors: Shiping Wang;Wenzhong Guo;
Appeared in: IEEE Transactions on Multimedia
Publication date: Jul 2017, volume: 19, issue:7, pages: 1454 - 1466
Publisher: IEEE
 
» Sparse Nonlinear Electromagnetic Imaging Accelerated With Projected Steepest Descent Algorithm
Abstract:
An efficient electromagnetic inversion scheme for imaging sparse 3-D domains is proposed. The scheme achieves its efficiency and accuracy by integrating two concepts. First, the nonlinear optimization problem is constrained using or -norm of the solution as the penalty term to alleviate the ill-posedness of the inverse problem. The resulting Tikhonov minimization problem is solved using nonlinear Landweber iterations (NLW). Second, the efficiency of the NLW is significantly increased using a steepest descent algorithm. The algorithm uses a projection operator to enforce the sparsity constraint by thresholding the solution at every iteration. Thresholding level and iteration step are selected carefully to increase the efficiency without sacrificing the convergence of the algorithm. Numerical results demonstrate the efficiency and accuracy of the proposed imaging scheme in reconstructing sparse 3-D dielectric profiles.
Autors: Abdulla Desmal;Hakan Bağcı;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jul 2017, volume: 55, issue:7, pages: 3810 - 3822
Publisher: IEEE
 
» Sparse Poisson Latent Block Model for Document Clustering
Abstract:
Over the last decades, several studies have demonstrated the importance of co-clustering to simultaneously produce groups of objects and features. Even to obtain object clusters only, using co-clustering is often more effective than one-way clustering, especially when considering sparse high dimensional data. In this paper, we present a novel generative mixture model for co-clustering such data. This model, the Sparse Poisson Latent Block Model (SPLBM), is based on the Poisson distribution, which arises naturally for contingency tables, such as document-term matrices. The advantages of SPLBM are two-fold. First, it is a rigorous statistical model which is also very parsimonious. Second, it has been designed from the ground up to deal with data sparsity problems. As a consequence, in addition to seeking homogeneous blocks, as other available algorithms, it also filters out homogeneous but noisy ones due to the sparsity of the data. Experiments on various datasets of different size and structure show that an algorithm based on SPLBM clearly outperforms state-of-the-art algorithms. Most notably, the SPLBM-based algorithm presented here succeeds in retrieving the natural cluster structure of difficult, unbalanced datasets which other known algorithms are unable to handle effectively.
Autors: Melissa Ailem;François Role;Mohamed Nadif;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Jul 2017, volume: 29, issue:7, pages: 1563 - 1576
Publisher: IEEE
 
» Sparse Representation for Signal Reconstruction in Calorimeters Operating in High Luminosity
Abstract:
A calorimeter signal reconstruction method, based on sparse representation (SR) of redundant data, is proposed for energy reconstruction in particle colliders operating in high-luminosity conditions. The signal overlapping is first modeled as an underdetermined linear system, leading to a convex set of feasible solutions. The solution with the smallest number of superimposed signals (the SR) that represents the recorded data is obtained through the use of an interior-point (IP) optimization procedure. From a signal processing point-of-view, the procedure performs a source separation, where the information of the amplitude of each convoluted signal is obtained. In the simulation results, a comparison of the proposed method with standard signal reconstruction one was performed. For this, a toy Monte Carlo simulation was developed, focusing in calorimeter front-end signal generation only, where the different levels of pileup and signal-to-noise ratio were used to qualify the proposed method. The results show that the method may be competitive in high-luminosity environments.
Autors: Davis P. Barbosa;Luciano M. de A. Filho;Bernardo S. Peralva;Augusto S. Cerqueira;José M. de Seixas;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Jul 2017, volume: 64, issue:7, pages: 1942 - 1949
Publisher: IEEE
 
» Sparsity Based Efficient Cross-Correlation Techniques in Sensor Networks
Abstract:
Cross-correlation is a popular signal processing technique used in numerous location tracking systems for obtaining reliable range information. However, its efficient design and practical implementation has not yet been achieved on mote platforms that are typical in wireless sensor network due to resource constrains. In this paper, we propose StructS-XCorr: cross-correlation via structured sparse representation, a new computing framework for ranging based on -norm minimization [1] and structured sparsity. The key idea is to compress the ranging signal samples on the mote by efficient random projections and transfer them to a central device; where a convex optimization process estimates the range by exploiting the sparse signal structure in the proposed correlation dictionary. Through theoretical validation, extensive empirical studies and experiments on an end-to-end acoustic ranging system implemented on resource limited off-the-shelf sensor nodes, we show that the proposed framework can achieve up to two orders of magnitude better performance compared to other approaches such as working on DCT domain and downsampling. Compared to the standard cross-correlation, it is able to obtain range estimates with a bias of 2-6 cm with 30 percent and approximately 100 cm with 5 percent compressed measurements. Its structured sparsity model is able to improve the ranging accuracy by 40 percent under challenging recovery conditions (such as high compression factor and low signal-to-noise ratio) by overcoming limitations due to dictionary coherence.
Autors: Prasant Misra;Wen Hu;Mingrui Yang;Marco Duarte;Sanjay Jha;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Jul 2017, volume: 16, issue:7, pages: 2037 - 2050
Publisher: IEEE
 
» Spatial Scattering Modulation for Uplink Millimeter-Wave Systems
Abstract:
In this letter, a new spatial scattering modulation (SSM) is proposed for uplink millimeter-wave (mmWave) systems that support a single user terminal (UT). By utilizing the analog and hybrid beamforming with a large antenna array and phase shifters for mmWave communications systems, an architecture, where the UT has a single radio-frequency (RF) chain, whereas the base station has more than one RF chain, is adopted. In this architecture, the proposed SSM modulates some information bits on the spatial directions of scattering clusters in the angular domain, so that a higher spectral efficiency can be achieved with the use of a lower order modulation. For a particular number of scattering clusters and a number of RF chains, a closed-form expression for the upper bound on the bit-error rate (BER) is derived for the proposed SSM. Monte Carlo simulations are also conducted to verify the achievable BER performance.
Autors: Yacong Ding;Kyeong Jin Kim;Toshiaki Koike-Akino;Milutin Pajovic;Pu Wang;Philip Orlik;
Appeared in: IEEE Communications Letters
Publication date: Jul 2017, volume: 21, issue:7, pages: 1493 - 1496
Publisher: IEEE
 
» Spatial Statistics for Segmenting Histological Structures in H&E Stained Tissue Images
Abstract:
Segmenting a broad class of histological structures in transmitted light and/or fluorescence-based images is a prerequisite for determining the pathological basis of cancer, elucidating spatial interactions between histological structures in tumor microenvironments (e.g., tumor infiltrating lymphocytes), facilitating precision medicine studies with deep molecular profiling, and providing an exploratory tool for pathologists. This paper focuses on segmenting histological structures in hematoxylin- and eosin-stained images of breast tissues, e.g., invasive carcinoma, carcinoma in situ, atypical and normal ducts, adipose tissue, and lymphocytes. We propose two graph-theoretic segmentation methods based on local spatial color and nuclei neighborhood statistics. For benchmarking, we curated a data set of 232 high-power field breast tissue images together with expertly annotated ground truth. To accurately model the preference for histological structures (ducts, vessels, tumor nets, adipose, etc.) over the remaining connective tissue and non-tissue areas in ground truth annotations, we propose a new region-based score for evaluating segmentation algorithms. We demonstrate the improvement of our proposed methods over the state-of-the-art algorithms in both region- and boundary-based performance measures.
Autors: Luong Nguyen;Akif Burak Tosun;Jeffrey L. Fine;Adrian V. Lee;D. Lansing Taylor;S. Chakra Chennubhotla;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jul 2017, volume: 36, issue:7, pages: 1522 - 1532
Publisher: IEEE
 
» Spatially Distributed MIMO Sonar Systems: Principles and Capabilities
Abstract:
Multiple-input–multiple-output (MIMO) sonar systems offer new perspectives for target detection and area surveillance. This paper introduces a unified formulation for sonar MIMO systems and focuses on the target detection and recognition capability of these systems. The multiplication of the number of transmitters and receivers not only provides a greater variety in terms of target view angles but also provides meaningful statistics on the target itself. Assuming that views are independent and the MIMO system is large enough, we demonstrate that target recognition is possible with only one MIMO snapshot. By studying the detection performance of MIMO sonars we also demonstrate that such systems solve the speckle noise and decorrelate individual scatterers inside one cell resolution, leading to super-resolution imaging. We also show that, if carefully designed, MIMO systems can surpass the resolution of a synthetic aperture sonar (SAS) system using the same bandwidth. All the discussed properties are derived from the independent view assumption. Fulfilling this assumption drives the design and efficiency of such systems.
Autors: Yan Pailhas;Yvan Petillot;Keith Brown;Bernard Mulgrew;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jul 2017, volume: 42, issue:3, pages: 738 - 751
Publisher: IEEE
 
» Spatiotemporal Prediction of Satellite Altimetry Sea Level Anomalies in the Tropical Pacific Ocean
Abstract:
This letter developes and validates a machine learning approach to forecast sea level anomalies (SLAs) derived from satellite altimetry in the tropical Pacific Ocean. The empirical orthogonal function (EOF), also known as principal component analysis, was used to extract dominant signals and reduce the dimensionality of data sets. Such dimensionality was decreased by describing spatial patterns (EOFs) and the corresponding temporal domains [principal components (PCs)]. Support vector regression (SVR) was employed to predict the time series obtained from the leading PCs. Thereafter, the temporal and spatial SLAs from the proposed EOFs were reconstructed to represent the spatiotemporal SLA prediction. Finally, the prediction result was compared with that of the conventional autoregressive integrated moving average (ARIMA) model. Both models reached satisfactory sea level predictions. Even so, intercomparison of the obtained results showed that the SVR significantly () outperformed the ARIMA model in sea level forecasting. That is, a considerably low root-mean-square error was attained for the differences between the predicted and observed mean SLAs.
Autors: Moslem Imani;Yi-Ching Chen;Rey-Jer You;Wen-Hau Lan;Chung-Yen Kuo;Jung-Chieh Chang;Ashraf Rateb;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jul 2017, volume: 14, issue:7, pages: 1126 - 1130
Publisher: IEEE
 
» Spatiotemporal Tracking of Ocean Current Field With Distributed Acoustic Sensor Network
Abstract:
A distributed networked underwater sensor (DNUS) system can provide ocean measurements over a wide area with a large number of sensors. This paper studies the estimation of the ocean current field observed by a DNUS system. Considering that the current field is correlated in time and space, we present a statistically-based acoustic travel time difference tomography method based on a Kalman filter (KF) to reconstruct and track the ocean current field. A spatiotemporal autoregressive (AR) model is used to describe the time evolution of the current field. In the spatiotemporal AR model, the observation region is divided into subtriangle grids. The subtriangles are partitioned into clusters and each cluster is assigned with one AR coefficient. Moreover, the AR coefficients are updated adaptively with the past estimated current velocities. The proposed method is verified with the synthetic observational data generated by a barotropic ocean model. Compared with the regular distributed processing method, the proposed ocean current field reconstruction and tracking method achieves a lower region-integrated root-mean-square error (RMSE). In addition, by making use of the spatiotemporal correlation, the proposed method is robust to the measurement link failure and burst errors in the DNUS system.
Autors: Ying Zhang;Huifang Chen;Wen Xu;T. C. Yang;Jiamin Huang;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Jul 2017, volume: 42, issue:3, pages: 681 - 696
Publisher: IEEE
 
» SPE: Security and Privacy Enhancement Framework for Mobile Devices
Abstract:
In this paper, we present a security and privacy enhancement (SPE) framework for unmodified mobile operating systems. SPE introduces a new layer between the application and the operating system and does not require a device be jailbroken or utilize a custom operating system. We utilize an existing ontology designed for enforcing security and privacy policies on mobile devices to build a policy that is customizable. Based on this policy, SPE provides enhancements to native controls that currently exist on the platform for privacy and security sensitive components. SPE allows access to these components in a way that allows the framework to ensure the application is truthful in its declared intent and ensure that the user’s policy is enforced. In our evaluation we verify the correctness of the framework and the computing impact on the device. Additionally, we discovered security and privacy issues in several open source applications by utilizing the SPE Framework. From our findings, if SPE is adopted by mobile operating systems producers, it would provide consumers and businesses the additional privacy and security controls they demand and allow users to be more aware of security and privacy issues with applications on their devices.
Autors: Brian Krupp;Nigamanth Sridhar;Wenbing Zhao;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Jul 2017, volume: 14, issue:4, pages: 433 - 446
Publisher: IEEE
 
» Spherical Cap Packing Asymptotics and Rank-Extreme Detection
Abstract:
We study the spherical cap packing problem with a probabilistic approach. Such probabilistic considerations result in an asymptotic sharp universal uniform bound on the maximal inner product between any set of unit vectors and a stochastically independent uniformly distributed unit vector. When the set of unit vectors are themselves independently uniformly distributed, we further develop the extreme value distribution limit of the maximal inner product, which characterizes its uncertainty around the bound. As applications of the above-mentioned asymptotic results, we derive: 1) an asymptotic sharp universal uniform bound on the maximal spurious correlation, as well as its uniform convergence in distribution when the explanatory variables are independently Gaussian distributed and 2) an asymptotic sharp universal bound on the maximum norm of a low-rank elliptically distributed vector, as well as related limiting distributions. With these results, we develop a fast detection method for a low-rank structure in high-dimensional Gaussian data without using the spectrum information.
Autors: Kai Zhang;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jul 2017, volume: 63, issue:7, pages: 4572 - 4584
Publisher: IEEE
 
» SPICE Modeling of Variable Inductors and Its Application to Single Inductor LED Driver Design
Abstract:
This paper presents a design, simulation, and evaluation procedure of a variable inductor (VI) for a recently proposed dc-grid LED driver. The design procedure is based on the use of SPICE behavioral modeling to implement the different elements of the equivalent reluctance model of the VI. Thus, the model merges both electrical and magnetic behavior of the VI, including magnetic and geometric features. The basic components of the model are presented in detail, making it possible their use in future designs of VI and other complex magnetic devices. Experimental results from both VI and LED driver prototypes are provided to compare with the simulation results. Obtained outcomes prove that the proposed design and modeling technique is an excellent way to verify theoretical designs and attain further insight about the operation of these complex magnetic devices.
Autors: J. Marcos Alonso;Marina S. Perdigão;Guirguis Zaki Abdelmessih;Marco A. Dalla Costa;Yijie Wang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2017, volume: 64, issue:7, pages: 5894 - 5903
Publisher: IEEE
 
» Stability Analysis of Sampled-Data Systems via Free-Matrix-Based Time-Dependent Discontinuous Lyapunov Approach
Abstract:
In this paper, a new time-dependent discontinuous Lyapunov functional, namely, free-matrix-based time-dependent discontinuous (FMBTDD) Lyapunov functional is introduced for stability analysis of sampled-data systems. First, a modified free-matrix-based integral inequality (MFMBII) is derived based on the existing free-matrix-based integral inequality [1] and it is applied to develop a stability criterion for sampled-data systems. And then, inspired by MFMBII, FMBTDD term is established that leads to efficient stability conditions. Four numerical examples are given to demonstrate the effectiveness of the proposed methods.
Autors: Tae H. Lee;Ju H. Park;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2017, volume: 62, issue:7, pages: 3653 - 3657
Publisher: IEEE
 
» Stabilization Via Generalized Homogeneous Approximations
Abstract:
We introduce a notion of generalized homogeneous approximation at the origin and at infinity which extends the classical notions and captures a large class of nonlinear systems, including (lower and upper) triangular systems. Exploiting this extension and although this extension does not preserve the basic properties of the classical notion, we give basic results concerning stabilization and robustness of nonlinear systems, by designing a homogeneous (in the generalized sense) feedback controller which globally asymptotically stabilizes a chain of power integrators and makes it the dominant part at infinity and at the origin (in the generalized sense) of the dynamics. Stability against nonlinear perturbation follows from domination arguments.
Autors: Stefano Battilotti;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Jul 2017, volume: 62, issue:7, pages: 3510 - 3517
Publisher: IEEE
 
» Standards and Guidelines for Grid-Connected Photovoltaic Generation Systems: A Review and Comparison
Abstract:
Motivated by concerns about the environment and energy shortages, considerable progress has recently been made in the development of photovoltaic (PV) and other forms of distributed generation. These developments have contributed greatly to awareness of the importance of renewable energy and governmental policies to revise energy priorities to ensure the adoption and significant growth of renewable energy. Safely and reliably interconnecting various PV generators is a major challenge in the development of modern power systems and the interconnection of PV may have effects that require close attention. Standards or guidelines for grid-connected PV generation systems considerably affect PV development. This investigation reviews and compares standards and guidelines for distributed generation, and especially for PV integration. Pertinent standards and guidelines that ensure the successful operation of PV systems are presented. This investigation serves as a reference for improving standards for grid-connected PV generation systems.
Autors: Yuan-Kang Wu;Jhih-Hao Lin;Huei-Jeng Lin;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2017, volume: 53, issue:4, pages: 3205 - 3216
Publisher: IEEE
 
» Static Elimination in Vacuum
Abstract:
Static charge on organic electronic devices during fabrication causes damage that decreases production rates. While corona ionizers have long been used to control static charge in silicon device production and on polymer sheets and films, static charge on organic devices must be neutralized in inert gases, often at reduced pressures to prevent degradation from oxygen exposure. Static elimination characteristics of ac corona ionizers in N2-CF3 I and N2-O2 gases at reduced pressure have been explored. The neutralizing current amplitude and voltage ripple on objects during static elimination rapidly increase when decreasing the gas pressure. The best static elimination performance can be attained by choosing the gas pressure and the ionizer frequency properly.
Autors: Takashi Ikehata;Daisuke Nemoto;Wanting He;Takeshi Matsuo;Naoyuki Sato;Kazuo Okano;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2017, volume: 53, issue:4, pages: 3989 - 3994
Publisher: IEEE
 
» Statistical Comparison and Combination of GPS, GLONASS, and Multi-GNSS Multipath Reflectometry Applied to Snow Depth Retrieval
Abstract:
Global navigation satellite system (GNSS) multipath reflectometry (MR) has emerged as a new technique that uses signals of opportunity broadcast by GNSS satellites and tracked by ground-based receivers to retrieve environmental variables such as snow depth. The technique is based on the simultaneous reception of direct or line-of-sight (LOS) transmissions and corresponding coherent surface reflections (non-LOS). Until recently, snow depth retrieval algorithms only used legacy and modernized GPS signals. Using multiple GNSS constellations for reflectometry would improve GNSS-MR applications by providing more observations from more satellites and independent signals (carrier frequencies and code modulations). We assess GPS and GLONASS for combined multi-GNSS-MR using simulations as well as field measurements. Synthetic observations for different signals indicated a lack of detectable interfrequency and intercode biases in GNSS-MR snow depth retrievals. Received signals from a GNSS station continuously operating in France for a two-winter period are used for experimental snow depth retrieval. We perform an internal validation of various GNSS signals against the proven GPS-L2-C signal, which was validated externally against in situ snow depth in previous studies. GLONASS observations required a more complex handling to account for topography because of its particular ground track repeatability. Signal intercomparison show an average correlation of 0.922 between different GPS snow depths and GPS-L2-CL, while GLONASS snow depth retrievals have an average correlation that exceeds 0.981. In terms of precision and accuracy, legacy GPS signals are worse, while GLONASS signals and modernized GPS signals are of comparable quality. Finally, we show how an optimal multi-GNSS combined daily snow depth time series can be formed employing variance factors with a ~59%–90% precision improvement compared to in- ividual signal snow depth retrievals, resulting in snow depth retrieval with uncertainty of 1.3 cm. The developed combination strategy can also be applied for the European Galileo and the Chines BeiDou navigation systems.
Autors: Sajad Tabibi;Felipe Geremia-Nievinski;Tonie van Dam;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jul 2017, volume: 55, issue:7, pages: 3773 - 3785
Publisher: IEEE
 
» Statistical CSIT Aided User Scheduling for Broadcast MU-MISO System
Abstract:
Recent studies show that the statistical channel state information (SCSI) helps to largely increase the capacity of communication systems when the instantaneous perfect CSI is unavailable. In this paper, we consider multiuser multiple-input-single-output broadcast channels where the transmitter has the knowledge of SCSI. The major issue of concern in our paper is to improve the average group-rate of the whole system by scheduling users over different time slots. With SCSI at the transmitter side, we are able to precode signals and, hence, compute the theoretical achievable group-rate of arbitrary user groups. Based on the group-rates, we propose tier-2 Munkres user scheduling algorithm (T2-MUSA) that leads to higher average group-rate than existing algorithms with generally better fairness. The optimality of the proposed algorithm in energy-fair user scheduling space is proved and we derive a lower bound of a special case to verify the validity of our simulations. In addition, many conventional user scheduling algorithms maintain queue stability by solving a weighted sum-rate (WSR) problem, using queue lengths to represent weight coefficients. Inspired by T2-MUSA, we propose a QoS-based MUSA (QB-MUSA) aimed at stabilizing queue lengths and maximizing throughput. In results, we show that QB-MUSA exhibits higher throughput than the conventional WSR-based algorithm.
Autors: Qi Cao;Yanjing Sun;Qiang Ni;Song Li;Zefu Tan;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2017, volume: 66, issue:7, pages: 6102 - 6114
Publisher: IEEE
 
» Statistical Properties of Marine Surface Slopes From Its Glitter Patterns: The 1-D Case
Abstract:
Statistical relationships between the glitter patterns of the sea surface versus the sea surface slopes for different wind velocities on the sea surface are presented. In order to obtain the statistical relationships and a suitable geometry, different heights of the detector and different lengths of the 1-D profiles of the sea surface were assumed using the OpenMP directives of CPU computing parallel. For this, a Gaussian and a non-Gaussian probability density function (pdf) for the sea surface slopes of the profile were considered, using a Rect and a Gaussian glitter function to model the geometry of the interaction of the sun on the sea profile. The curves have inflection points at different wind velocities on the sea surface for all the cases considered, where the results showed a similar behavior of the curves for both the glitter functions. Higher values for the variances of the intensities of the image using the Rect glitter function were found because the Gaussian glitter function contains less energy and a significant decrease in the values when the detector height increases. The behavior of the curves of variance depends on a large percentage of the angles of incidence. To apply a non-Gaussian pdf instead of a Gaussian pdf provides variance curves slightly smoothed but with similar values, so one of these pdfs can be used to represent both. The same occurs in the correlation function. The results present some geometry examples that can be used to optimize the experiment design.
Autors: Claudia Andrea Vidales-Basurto;Josué Álvarez-Borrego;José Luis Poom-Medina;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jul 2017, volume: 55, issue:7, pages: 4211 - 4219
Publisher: IEEE
 
» Stator Lamination Geometry Influence on the Building Factor of Synchronous Reluctance Motor Cores
Abstract:
The study investigates the influence of the lamination geometry on the building factor of stator magnetic cores, quantifying by experiments the influence of the punching and the annealing process. The research and the experimental activity are focused on small-fractional-power synchronous reluctance motors, where the effect of the punching process is expected to be very impacting, not only for the stator iron losses increase, but also because the current magnetizing component is dominant in the total input current. However, the obtained results are particularly interesting for any fractional and low power electric machines, whose cores are built with punched or laser-cut laminations.
Autors: Andrea Cavagnino;Radu Bojoi;Zbigniew Gmyrek;Marcin Lefik;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2017, volume: 53, issue:4, pages: 3394 - 3403
Publisher: IEEE
 
» Steady-State Analysis and Design Considerations of High Voltage Gain Switched Z-Source Inverter With Continuous Input Current
Abstract:
In this paper, a new topology for Z-source inverter based on switched Z-source network is proposed. The proposed switched Z-source inverter can provide high voltage gain in low duty cycles. The continuous input current is one of the other advantages of the proposed inverter. The performance of the proposed inverter is investigated in different operating modes and the voltage and current equations of all elements and equations of critical inductance are calculated. Furthermore, the power losses and efficiency analyses are presented. The comprehensive comparison between the proposed inverter and the other conventional Z-source inverters shows its excellent performance. Finally, to prove the correct operation of the proposed topology, the experimental and simulation results using PSCAD/EMTDC software are presented.
Autors: Mohsen Hasan Babayi Nozadian;Ebrahim Babaei;Seyed Hossein Hosseini;Elias Shokati Asl;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2017, volume: 64, issue:7, pages: 5342 - 5350
Publisher: IEEE
 
» STEM: A Scheme for Two-Phase Evaluation of Majority Logic
Abstract:
The switching time of a magnet in a spin-current-based majority gate depends on the input vector combination, and this often restricts the speed of majority-based circuits. To address this issue, this work proposes a novel two-phase scheme to implement majority logic and evaluates it on an all-spin logic (ASL) majority-based logic structures. In Phase 1, the output is initialized to a preset value. Next, in Phase 2, the inputs are evaluated to switch the output magnet to its correct value. The time window for the output to switch in Phase 2 is fixed. Using such a scheme, an -input AND gate that requires a total of ( ) inputs in the conventional implementation can now be implemented with only () inputs. When applied to standard logic functions, it is demonstrated that the proposed method of designing ASL gates is 1.6–3.4 faster and 1.9–6.9 more energy efficient than the conventional method, and for a five-magnet full adder, it is shown that the proposed ASL implementation is 1.5 faster, 2.2 more energy efficient, and provides a 16% improvement in area.
Autors: Meghna G. Mankalale;Zhaoxin Liang;Sachin S. Sapatnekar;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jul 2017, volume: 16, issue:4, pages: 606 - 615
Publisher: IEEE
 
» Stimulating Vibration in Magnetoelastic Beams by the Circumferential Fields of Conducted Currents
Abstract:
A means to cause continuous vibratory deflection of a flexurally stressed beam of ferromagnetic, non-zero magnetostriction material, by a longitudinally conducted time varying current is described. The deflection of a horizontal cantilever beam, caused by a weight attached at its free end, is due to a difference in strains between those regions under tensile stress and those under compressive stress, in which these strains have both mechanical and magnetoelastic components. The circumferential uniformity of the field from the current acts to reduce the magnetoelastic strain inequality, hence also a small portion of the beam’s deflection. Alternating between current on and current off thus acts to raise and lower the weight. Cycling the applied current at a frequency that matches the prime mode frequency will produce vibratory deflection. Round wire beams, 20–85 mm long, ~1 mm diameter, of three different materials, with attached weights ranging from 60 to 600 mN were made to vibrate at their specific natural frequency (8–80 Hz) with peak strokes up to >10 mm by currents alternating between 0 and up to 9 A.
Autors: Ivan J. Garshelis;Ryan J. Kari;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2017, volume: 53, issue:7, pages: 1 - 10
Publisher: IEEE
 
» Stochastic Resource Provisioning for Containerized Multi-Tier Web Services in Clouds
Abstract:
Under today's bursty web traffic, the fine-grained per-container control promises more efficient resource provisioning for web services and better resource utilization in cloud datacenters. In this paper, we present Two-stage Stochastic Programming Resource A llocator (2SPRA). It optimizes resource provisioning for containerized n-tier web services in accordance with fluctuations of incoming workload to accommodate predefined SLOs on response latency. In particular, 2SPRA is capable of minimizing resource over-provisioning by addressing dynamics of web traffic as workload uncertainty in a native stochastic optimization model. Using special-purpose OpenOpt optimization framework, we fully implement 2SPRA in Python and evaluate it against three other existing allocation schemes, in a Docker-based CoreOS Linux VMs on Amazon EC2. We generate workloads based on four real-world web traces of various traffic variations: AOL, WorldCup98, ClarkNet, and NASA. Our experimental results demonstrate that 2SPRA achieves the minimum resource over-provisioning outperforming other schemes. In particular, 2SPRA allocates only 6.16 percent more than application's actual demand on average and at most 7.75 percent in the worst case. It achieves 3x further reduction in total resources provisioned compared to other schemes delivering overall cost-savings of 53.6 percent on average and up to 66.8 percent. Furthermore, 2SPRA demonstrates consistency in its provisioning decisions and robust responsiveness against workload fluctuations.
Autors: Omer Adam;Young Choon Lee;Albert Y. Zomaya;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jul 2017, volume: 28, issue:7, pages: 2060 - 2073
Publisher: IEEE
 
» Strain Analysis of Six-Axis Force/Torque Sensors Based on Analytical Method
Abstract:
Reasonable stress and strain distribution are essential for the design of six-axis force/torque sensors. In order to improve the strain distribution, the specific parameters which affect stress and strain distribution need to be found. The numerical solutions of stress and strain on the elastic beam of six-axis force/torque sensors can be quickly obtained by finite element analysis simulation tool, such as ANSYS, but the specific parameters which affect stress and strain distribution cannot be achieved. In this paper, a novel six-axis force/torque sensor scheme with small size and cross beam structure was presented. Then, the mechanical model and analytic equations based on Timoshenko beam theory were established to obtain the analytical solutions of strain. The comparison shows that the analytical solutions and numerical solutions are in good agreement, which indicates that the analytical method is feasible. Finally, the main parameters which affect the strain value and the measure accuracy were analyzed. The analysis results show that the design of six-axis force/torque sensors with cross beam structure can be optimized according to the parameters that affect the stress and strain distribution, if sufficient restrictions are offered.
Autors: Yingjian Wang;Guokun Zuo;Xiliang Chen;Liang Liu;
Appeared in: IEEE Sensors Journal
Publication date: Jul 2017, volume: 17, issue:14, pages: 4394 - 4404
Publisher: IEEE
 
» Structured and Sparse Canonical Correlation Analysis as a Brain-Wide Multi-Modal Data Fusion Approach
Abstract:
Multi-modal data fusion has recently emerged as a comprehensive neuroimaging analysis approach, which usually uses canonical correlation analysis (CCA). However, the current CCA-based fusion approaches face problems like high-dimensionality, multi-collinearity, unimodal feature selection, asymmetry, and loss of spatial information in reshaping the imaging data into vectors. This paper proposes a structured and sparse CCA (ssCCA) technique as a novel CCA method to overcome the above problems. To investigate the performance of the proposed algorithm, we have compared three data fusion techniques: standard CCA, regularized CCA, and ssCCA, and evaluated their ability to detect multi-modal data associations. We have used simulations to compare the performance of these approaches and probe the effects of non-negativity constraint, the dimensionality of features, sample size, and noise power. The results demonstrate that ssCCA outperforms the existing standard and regularized CCA-based fusion approaches. We have also applied the methods to real functional magnetic resonance imaging (fMRI) and structural MRI data of Alzheimer’s disease (AD) patients (n = 34) and healthy control (HC) subjects (n = 42) from the ADNI database. The results illustrate that the proposed unsupervised technique differentiates the transition pattern between the subject-course of AD patients and HC subjects with a p-value of less than . Furthermore, we have depicted the brain mapping of functional areas that are most correlated with the anatomical changes in AD patients relative to HC subjects.
Autors: Ali-Reza Mohammadi-Nejad;Gholam-Ali Hossein-Zadeh;Hamid Soltanian-Zadeh;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Jul 2017, volume: 36, issue:7, pages: 1438 - 1448
Publisher: IEEE
 
» Structured Group Sparsity: A Novel Indoor WLAN Localization, Outlier Detection, and Radio Map Interpolation Scheme
Abstract:
This paper introduces novel schemes for indoor localization, outlier detection, and radio map interpolation using wireless local area networks. The localization method consists of a novel multicomponent optimization technique that minimizes the squared -norm of the residuals between the radio map and the online received signal strength (RSS) measurements, the -norm of the user's location vector, and weighted -norms of layered groups of reference points (RPs). RPs are grouped using a new criterion based on the similarity between the so-called access point (AP) coverage vectors. In addition, since AP readings are prone to containing inordinate readings, called outliers, an augmented optimization problem is proposed to detect the outliers and localize the user with cleaned online measurements. Moreover, a novel scheme to record fingerprints from a smaller number of RPs and estimate the radio map at RPs without recorded fingerprints is developed using sparse recovery techniques. All localization schemes are tested on RSS fingerprints collected from a real environment. The overall scheme has comparable complexity with competing approaches, while it performs with high accuracy under a small number of APs and finer granularity of RPs.
Autors: Ali Khalajmehrabadi;Nikolaos Gatsis;David Akopian;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2017, volume: 66, issue:7, pages: 6498 - 6510
Publisher: IEEE
 
» Study of Terahertz Radiation Generation by Two Laser Beams in an Axial Magnetized Rippled Density Plasma
Abstract:
This paper presents a scheme to achieve terahertz radiation by the beating of top-hat lasers in a rippled density collisional magnetized plasma. The nonlinear current at terahertz frequency arises on account of nonlinear ponderomotive force as a result of beating of the two lasers. A uniform static magnetic field which is considered parallel to the direction of lasers leads to, depending on the phase-matching conditions, propagation of right-hand circularly polarized (RCP) or left-hand circularly polarized (LCP) waves in plasma. It is found that, terahertz amplitude of RCP wave for high values of beating frequency is slightly larger than LCP wave. The contribution of magnetic field, laser index and collision frequency are discussed for the efficient terahertz radiation generation. With the optimization of these parameters, the efficiency of order of 25 percent can be achieved in the present scheme.
Autors: Ayoob Hematizadeh;Seyed Masud Jazayeri;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Jul 2017, volume: 45, issue:7, pages: 1717 - 1722
Publisher: IEEE
 
» Study of the Influence of Various Stress-Based Mechanisms on Polarization of an SM mPOF for the Development of Useful Devices
Abstract:
In contrast to conventional polymer optical fibres (POFs), single-mode microstructured POFs (SM mPOF) exhibit polarization properties that make them potentially interesting for their use in the design and development of polarimetric fibre optic systems. In spite of the theoretical sixfold symmetry of the microstructure that yields zero linear birefringence, a measurement technique reveals us that the SM mPOF behaves as a linear birefringent system with clearly defined optical axes and characteristics. Regarding externally induced birefringence mechanisms acting upon the SM mPOF, either bend- and pressure-induced retardations or twist-induced light rotation follow the behaviour predicted theoretically. More specifically, bend-induced retardation varies linearly with the inverse square of the bending radius of the fibre, and in the case of asymmetrical lateral stress, pressure-induced retardation varies with the applied force. As to twist-induced rotation, the electric field rotates linearly with the angle through which the fibre is twisted. All cases are highly reproducible phenomena that, if used advantageously, may yield useful mPOF-based polarimetric optical devices not exploited yet.
Autors: Gaizka Durana;Oskar Arrizabalaga;Eneko Arrospide;Gotzon Aldabaldetreku;Joseba Zubia;Mikel Azkune;
Appeared in: Journal of Lightwave Technology
Publication date: Jul 2017, volume: 35, issue:14, pages: 3035 - 3041
Publisher: IEEE
 
» Study on Corona Activity Using an Image Processing Approach
Abstract:
In the present work, behavior of corona discharges on the polymeric insulating sample, generated from a multiple needle electrode in the presence of normal air and fog (mist) condition, is studied with the aid of an image processing technique. The development of streamers is closely monitored using the high-resolution digital single lens reflection camera. The corona streamers were found to be concentrated in the presence of fog whereas without the fog, streamers spread was wider. A physical model is proposed to explain the observed phenomenon. The obtained digital corona images are processed in the YCbCr color space to effectively extract corona generated plasma using color thresholding method. The streamer spread angle is then calculated by applying the Hough transform technique. The results indicate that streamer spread angle in the presence of fog to be approximately 60% lower than that without fog. Concentrated streamers during fog application are found to damage the polymeric samples more intensely. Scanning electron microscopic (SEM) is conducted on the treated sample and total crack portion is determined by processing SEM images. A linear match is found between the measured surface roughness and extracted crack portion of the treated sample. This paper highlights the possible application of image processing—as one of the tool in analyzing the corona activities and its effect particularly on polymeric insulators.
Autors: D. Shakthi Prasad;B. Subba Reddy;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2017, volume: 53, issue:4, pages: 4008 - 4014
Publisher: IEEE
 
» Sub-Thermal Subthreshold Characteristics in Top–Down InGaAs/InAs Heterojunction Vertical Nanowire Tunnel FETs
Abstract:
This letter demonstrates top-down InGaAs/ InAs heterojunction vertical nanowire tunnel FETs with sub-thermal subthreshold characteristics over two orders of magnitude of current. A minimal subthreshold swing of 53 mV/decade at V has been obtained at room temperature. An I60 (defined as the highest current level where the subthreshold characteristics exhibit a transition from sub- to super-60 mV/decade behavior) of 4.3 nA/ has been achieved at V. Compared with an earlier device generation, much reduced temperature dependence of the subthresholdcharacteristics is observed in this letter. The major difference between the two device generations is the drastically reduced interface trap density, evidenced by the improvement in the subthreshold swing of InGaAs vertical nanowire MOSFETs fabricated at the same time. This result suggests oxide–semiconductor interface trap-assisted tunnelling the main leakage mechanism in III-V TFETs fabricated by our process. The improvement in the interface quality has been enabled by improved gate oxide deposition and post-deposition treatment.
Autors: Xin Zhao;Alon Vardi;Jesús A. del Alamo;
Appeared in: IEEE Electron Device Letters
Publication date: Jul 2017, volume: 38, issue:7, pages: 855 - 858
Publisher: IEEE
 
» Submillimeter Wavelength 2-D Frequency Scanning Antenna Based on Slotted Waveguides Fed Through a Phase Shifting Network
Abstract:
This paper describes a 2-D frequency scanning array, operating in the 240–310-GHz frequency range, which is intended to be used in electromagnetic imaging applications. The proposed antenna combines eight slotted waveguides that are parallel fed through a frequency-dependent phase shifting network. As the working frequency is swept in the considered range, the inherent frequency-dependent behavior of the slotted waveguide causes beam scanning in one plane, while the progressive phase shift introduced by the feeding network provides beam steering in the perpendicular direction. The influence of the particular negative effects that suffer the employed structures on the array performance is carefully analyzed to determine the viability of this approach. A prototype has been implemented and experimentally characterized. The manufactured antenna presents a measured 20-dBi minimum gain and it is able to scan a space region, which would be large enough for a great number of imaging applications.
Autors: René Camblor;Samuel Ver Hoeye;Miguel Fernández;Carlos Vázquez Antuña;Fernando Las-Heras;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jul 2017, volume: 65, issue:7, pages: 3501 - 3509
Publisher: IEEE
 
» Substrate Integrated Waveguide L-Shaped Iris for Realization of Transmission Zero and Evanescent-Mode Pole
Abstract:
This paper investigates L-shaped iris (LSI) embedded in substrate integrated waveguide (SIW) structures. A lumped element equivalent circuit is utilized to thoroughly discuss the iris behavior in a wide frequency band. This structure has one more degree of freedom and design parameter compared with the conventional iris structures; therefore, it enables design flexibility with enhanced performance. The LSI is utilized to realize a two-pole evanescent-mode filter with an enhanced stopband and a dual-band filter combining evanescent and ordinary modes excitation. Moreover, a prescribed filtering function is demonstrated using the lumped element analysis not only including evanescent-mode pole, but also close-in transmission zero. The proposed LSI promises to substitute the conventional posts in (SIW) filter design.
Autors: Mehdi Nosrati;Mojgan Daneshmand;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jul 2017, volume: 65, issue:7, pages: 2310 - 2320
Publisher: IEEE
 
» Sum-Rate Maximization in Sub-28-GHz Millimeter-Wave MIMO Interfering Networks
Abstract:
MIMO systems in the lower part of the millimetre-wave (mmWave) spectrum band (i.e., below 28 GHz) do not exhibit enough directivity and selectively, as compared to their counterparts in higher bands of the spectrum (i.e., above 60 GHz), and thus still suffer from the detrimental effect of interference, on the system sum rate. As such systems exhibit large numbers of antennas and short coherence times for the channel, traditional methods of distributed coordination are ill-suited, and the resulting communication overhead would offset the gains of coordination. In this paper, we propose algorithms for tackling the sum-rate maximization problem that are designed to address the above-mentioned limitations. We derive a lower bound on the sum rate, a so-called difference of log and trace (DLT) bound, shed light on its tightness, and highlight its decoupled nature at both the transmitters and receivers. Moreover, we derive the solution to each of the subproblems that we dub non-homogeneous waterfilling (a variation on the MIMO waterfilling solution), and underline an inherent desirable feature: its ability to turn-OFF streams exhibiting low SINR, and contribute to greatly speeding up the convergence of the proposed algorithm. We then show the convergence of the resulting algorithm, max-DLT, to a stationary point of the DLT bound. Finally, we rely on extensive simulations of various network configurations, to establish the fast-converging nature of our proposed schemes, and thus their suitability for addressing the short coherence interval, as well as the increased system dimensions, arising when managing interference in lower bands of the mmWave spectrum. Moreover, our results suggest that interference management still brings about significant performance gains, especially in dense deployments.
Autors: Hadi Ghauch;Taejoon Kim;Mats Bengtsson;Mikael Skoglund;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Jul 2017, volume: 35, issue:7, pages: 1649 - 1662
Publisher: IEEE
 
» Superheroes and Scientists as Agents for Societal and Technological Advancement
Abstract:
With their current rise to prominence, it is near impossible to avoid superheroes (and villains) in every sphere of life in the world around us. With comics, hit television shows, video games, and blockbuster films, it is quite obvious that the public has connected with these characters-many of them decades old-in an unprecedented way, and the trend does not appear to be slowing down. To some, this development is driven by nostalgia. I grew up as a comicbook reader and fondly remember mornings watching X-Men: The Animated Series and going through gobs of quarters keeping Wolverine alive in the X-Men arcade game.
Autors: Suveen N. Mathaudhu;
Appeared in: IEEE Potentials
Publication date: Jul 2017, volume: 36, issue:4, pages: 24 - 29
Publisher: IEEE
 
» Superpixel-Based Multiple Local CNN for Panchromatic and Multispectral Image Classification
Abstract:
Recently, very high resolution (VHR) panchromatic and multispectral (MS) remote-sensing images can be acquired easily. However, it is still a challenging task to fuse and classify these VHR images. Generally, there are two ways for the fusion and classification of panchromatic and MS images. One way is to use a panchromatic image to sharpen an MS image, and then classify a pan-sharpened MS image. Another way is to extract features from panchromatic and MS images, respectively, and then combine these features for classification. In this paper, we propose a superpixel-based multiple local convolution neural network (SML-CNN) model for panchromatic and MS images classification. In order to reduce the amount of input data for the CNN, we extend simple linear iterative clustering algorithm for segmenting MS images and generating superpixels. Superpixels are taken as the basic analysis unit instead of pixels. To make full advantage of the spatial-spectral and environment information of superpixels, a superpixel-based multiple local regions joint representation method is proposed. Then, an SML-CNN model is established to extract an efficient joint feature representation. A softmax layer is used to classify these features learned by multiple local CNN into different categories. Finally, in order to eliminate the adverse effects on the classification results within and between superpixels, we propose a multi-information modification strategy that combines the detailed information and semantic information to improve the classification performance. Experiments on the classification of Vancouver and Xi’an panchromatic and MS image data sets have demonstrated the effectiveness of the proposed approach.
Autors: Wei Zhao;Licheng Jiao;Wenping Ma;Jiaqi Zhao;Jin Zhao;Hongying Liu;Xianghai Cao;Shuyuan Yang;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jul 2017, volume: 55, issue:7, pages: 4141 - 4156
Publisher: IEEE
 
» Superresolution for UAV Images via Adaptive Multiple Sparse Representation and Its Application to 3-D Reconstruction
Abstract:
We propose a superresolution (SR) algorithm based on adaptive sparse representation via multiple dictionaries for images taken by unmanned aerial vehicles (UAVs). The SR attainable through the proposed algorithm can increase the precision of 3-D reconstruction from UAV images, enabling the production of high-resolution images for constructing high-frequency time series and for high-precision digital mapping in agriculture. The basic idea of the proposed method is to use a field server or ground-based camera to take training images and then construct multiple pairs of dictionaries based on selective sparse representations to reduce instability during the sparse coding process. The dictionaries are classified on the basis of the edge orientation into five clusters: 0, 45, 90, 135, and nondirection. The proposed method is expected to reduce blurring, blocking, and ringing artifacts especially in edge areas. We evaluated the proposed and previous methods using peak signal-to-noise ratio, structural similarity, feature similarity, and computation time. Our experimental results indicate that the proposed method clearly outperforms other state-of-the-art algorithms based on qualitative and quantitative analysis. In the end, we demonstrate the effectiveness of our proposed method to increase the precision of 3-D reconstruction from UAV images.
Autors: Muhammad Haris;Takuya Watanabe;Liu Fan;Muhammad Rahmat Widyanto;Hajime Nobuhara;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Jul 2017, volume: 55, issue:7, pages: 4047 - 4058
Publisher: IEEE
 
» Supervised Learning of Human Welder Behaviors for Intelligent Robotic Welding
Abstract:
Current industrial welding robots are mostly articulated arms with a pre-programmed set of movement, which lack the intelligence skilled human welders possess. In this paper, human welder's response against 3-D weld pool surface is learned and transferred to the welding robots to perform automated welding tasks. To this end, an innovative teleoperated virtualized welding platform is utilized to conduct dynamic training experiments by a human welder whose arm movements together with the 3-D weld pool characteristic parameters are recorded. The data is off-line rated by the welder and a fuzzy classifier is trained, using an adaptive neuro-fuzzy inference system (ANFIS), to automate the rating. Data from the training experiments are then automatically classified such that top rated data pairs are selected to model and extract “good response” minimizing the effect from “bad operation” made during the training. A supervised ANFIS model is then proposed to correlate the 3-D weld pool characteristic parameters and welder's adjustment on the welding speed. The obtained model is then transferred to the welding robot to perform automated welding task as an intelligent controller. Experiment results verified that the proposed model is able to control the process under different welding current as well as under disturbances in speed and measurement. A foundation is thus established to selectively learn “good response” to rapidly extract human intelligence to transfer into welding robots.
Autors: Yu-Kang Liu;Yu-Ming Zhang;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Jul 2017, volume: 14, issue:3, pages: 1532 - 1541
Publisher: IEEE
 
» Supporting Change Impact Analysis Using a Recommendation System: An Industrial Case Study in a Safety-Critical Context
Abstract:
Change Impact Analysis (CIA) during software evolution of safety-critical systems is a labor-intensive task. Several authors have proposed tool support for CIA, but very few tools were evaluated in industry. We present a case study on ImpRec, a recommendation System for Software Engineering (RSSE), tailored for CIA at a process automation company. ImpRec builds on assisted tracing, using information retrieval solutions and mining software repositories to recommend development artifacts, potentially impacted when resolving incoming issue reports. In contrast to the majority of tools for automated CIA, ImpRec explicitly targets development artifacts that are not source code. We evaluate ImpRec in a two-phase study. First, we measure the correctness of ImpRec’s recommendations by a simulation based on 12 years’ worth of issue reports in the company. Second, we assess the utility of working with ImpRec by deploying the RSSE in two development teams on different continents. The results suggest that ImpRec presents about 40 percent of the true impact among the top-10 recommendations. Furthermore, user log analysis indicates that ImpRec can support CIA in industry, and developers acknowledge the value of ImpRec in interviews. In conclusion, our findings show the potential of reusing traceability associated with developers’ past activities in an RSSE.
Autors: Markus Borg;Krzysztof Wnuk;Björn Regnell;Per Runeson;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Jul 2017, volume: 43, issue:7, pages: 675 - 700
Publisher: IEEE
 
» Supporting Wide-Band Circular Polarization: CRLH Networks for High-Performance CP Antenna Arrays
Abstract:
Supporting wide-band circular polarization (CP) over broad bandwidths poses a significant challenge for patch antennas and arrays. In any CP antenna, not only must the antenna's impedance-matching requirements be met; the circularity of the radiated wave polarization must be considered as well [1]. The circularity can be defined by a wave's axial ratio (AR), which describes the variation of the instantaneous electric field magnitude versus time. An AR of lower than 3 dB is usually sufficient to ensure good circularity, although many high-performance applications demand 1 dB or less. The difficulty is in the timing of the two polarizations created to form the CP wave. At microwave frequencies, even errors on the order of tens of picoseconds can dramatically worsen the circularity.
Autors: Joshua M. Kovitz;Jun H. Choi;Yahya Rahmat-Samii;
Appeared in: IEEE Microwave Magazine
Publication date: Jul 2017, volume: 18, issue:5, pages: 91 - 104
Publisher: IEEE
 
» Suppressing Zero-Sequence Circulating Current of Modular Interleaved Three-Phase Converters Using Carrier Phase Shift PWM
Abstract:
Zero-sequence circulating current (ZSCC) has been a major concern for the operation of paralleled converters. Existing ZSCC reduction methods in the literature either suffer poor performances or are too complicated for modular implementation in an arbitrary number of interleaved converters. This paper investigates the application of interleaved carrier phase-shift (ICPS) pulse-width modulation (PWM) in modular interleaved converter system for ZSCC peak value reduction. The generalized study based on the derived ZSCC analytical expression reveals that the ICPS PWM can achieve superior ZSCC peak value reduction performance regardless the number of interleaved converters. Moreover, the impacts of ICPS PWM on the output voltage and current quality are also analyzed based on double Fourier integral. Compared with the conventional interleaved sinusoidal PWM (ISPWM), the output quality with the ICPS PWM can be comparable or even better. Simulation and experimental results show good agreement with the theoretical analysis, verifying the performance of the ICPS PWM.
Autors: Zhongyi Quan;Yun Wei Li;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2017, volume: 53, issue:4, pages: 3782 - 3792
Publisher: IEEE
 
» Suppression of Azimuth Ambiguities of Strong Point-Like Targets for Multichannel SAR Systems
Abstract:
Multichannel synthetic aperture radar (SAR) signal reconstruction methods can effectively suppress azimuth ambiguities and achieve high-resolution wide-swath imaging. However, due to the characteristics of the practical antenna patterns, there exist non-bandlimited Doppler spectra, which will result in residual azimuth ambiguities, especially for strong targets. This letter presents a novel method for the suppression of the azimuth ambiguities of the strong point-like targets. First, we find out the positions of the strong point-like targets from the multichannel reconstructed SAR image. Then, we locate the ambiguous range history of each strong point-like target. Finally, the ambiguous components in the range history are filtered out by an orthogonal projection method. Therefore, the spectra of the strong point-like targets will be converted into the bandlimited spectra, and then, the azimuth ambiguities can be effectively suppressed by the conventional multichannel SAR signal reconstruction methods. Theoretical analysis and experiments demonstrate the feasibility of the proposed methods.
Autors: Xiaojiang Guo;Yesheng Gao;Kaizhi Wang;Xingzhao Liu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jul 2017, volume: 14, issue:7, pages: 1046 - 1050
Publisher: IEEE
 
» Surface Effect and Nonlocal Effect on Nanowires Bent by a Point Force at an Arbitrary Axial Position
Abstract:
Under different boundary conditions, the nanowires bent by a point force at an arbitrary axial position are studied analytically by considering the surface effect and the nonlocal effect. The surface effect is modeled to be the superposition of the forces induced from residual surface tension and surface elasticities. For the purpose of modeling the residual surface tension, the generalized Young–Laplace equation is introduced into the Euler–Bernoulli beam equation. The surface elasticities are taken into account via a core-shell model. An additional term is added in the bending moment equation in order to describe the nonlocal effect. Closed-form analytical solutions are obtained, indicating that both the surface effect and the nonlocal effect, as well as the boundary conditions and the force position, may influence the force–displacement curves of the bending nanowires. The solutions are compared with previous research studies. This work suggests that the applied force position and the boundary conditions may influence the experimentally measured Young's moduli of bending nanowires.
Autors: Jin He;Zhong Yan;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jul 2017, volume: 16, issue:4, pages: 527 - 533
Publisher: IEEE
 
» Surface Plasmonic Lattice Solitons in Semi-Infinite Graphene Sheet Arrays
Abstract:
We investigate the surface plasmonic lattice solitons (PLSs) in semi-infinite graphene sheet arrays. The surface soliton is formed as the surface plasmon polaritons (SPPs) tunneling is inhibited by the graphene nonlinearity, and meanwhile the incident power should be above a threshold value. Thanks to the strong confinement of SPPs on graphene, the effective width of surface PLSs can be squeezed into deep-subwavelength scale of ∼0.002λ . The influence of the graphene loss on the surface PLSs is also discussed. Based on the stable propagation of surface PLSs, we find that the light propagation can be switched from the array boundary to the inner graphene sheets by reducing the incident power or increasing the chemical potential of graphene. The study may find promising application in optical switches on deep-subwavelength scale.
Autors: Zhouqing Wang;Bing Wang;Hua Long;Kai Wang;Peixiang Lu;
Appeared in: Journal of Lightwave Technology
Publication date: Jul 2017, volume: 35, issue:14, pages: 2960 - 2965
Publisher: IEEE
 
» Surface Wave Dispersion for a Tunable Grounded Liquid Crystal Substrate Without and With Metasurface on Top
Abstract:
The surface wave dispersion of a grounded layer of liquid crystals (LCs) is investigated by taking into account the inherent electrical reconfigurability of such a material. The spectral dyadic impedance Green’s function of the tunable LC grounded slab is calculated and the dispersion curve of the fundamental mode supported by the structure is presented, showing that the orientation of the optical axis of the LCs modifies the surface wave dispersion curve significantly enough to be applied for surface wave propagation control. Furthermore, it is demonstrated that the presence of an inductive metasurface on top of the LC layer impressively reduces the resonance frequency and increases the sensitivity to the continuous voltage biasing.
Autors: Santi C. Pavone;Enrica Martini;Francesco Caminita;Matteo Albani;Stefano Maci;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Jul 2017, volume: 65, issue:7, pages: 3540 - 3548
Publisher: IEEE
 
» SybilVote: Formulas to Quantify the Success Probability of Sybil Attack in Online Social Network Voting
Abstract:
This letter proposes to derive the success probability of Sybil attack in online social networks with the multiple-choice majority voting. The resultant SybilVote formulas produce outputs that are consistent with the Monte Carlo simulation and more accurate than the existing formula based on the multinomial distribution tail estimate. The computational complexity of SybilVote exact formulas is , where , , and are the number of real users, choices, and Sybil users, respectively. The accurate approximation formula of SybilVote is also presented with complexity by using a normal distribution approximation available when and are large in a large-population user voting condition. Finally, the effects of parameters on the success probability of Sybil attack have been investigated to highlight usefulness of the formulas.
Autors: Teerapol Silawan;Chaodit Aswakul;
Appeared in: IEEE Communications Letters
Publication date: Jul 2017, volume: 21, issue:7, pages: 1553 - 1556
Publisher: IEEE
 
» Symbol Cyclic Shift Equalization PAM-OFDM—A Low Complexity CP-Free OFDM Scheme
Abstract:
In traditional orthogonal frequency division multiplexing (OFDM) systems, a cyclic prefix (CP) must be used in every block for intersymbol interference (ISI) suppression in time-dispersive channels at a price of severely impaired spectrum efficiency. To deal with this issue, the symbol cyclic shift equalization (SCSE) algorithm was proposed to implement a CP-free OFDM system. In this paper, we aim to further reduce the computational complexity of the SCSE algorithm. In particular, a pulse amplitude modulation (PAM) is used at a transmitter to construct conjugate symmetric OFDM blocks, while only partial samples in an OFDM block are involved in the SCSE algorithm at the receiver side, leading to a significantly reduced implementation complexity if compared to an SCSE quadratic-amplitude modulation(QAM)/phase-shift keying (PSK)-OFDM system, where all samples in an OFDM block must be involved in the detection process. The performance of the proposed SCSE PAM-OFDM scheme is analyzed and compared to traditional OFDM systems. The results obtained from this paper verify the effectiveness of the proposed scheme.
Autors: Xi-Qing Liu;Hsiao-Hwa Chen;Bo-Yu Lyu;Wei-Xiao Meng;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2017, volume: 66, issue:7, pages: 5933 - 5946
Publisher: IEEE
 
» Synchronous Generator Brushless Field Excitation and Voltage Regulation via Capacitive Coupling Through Journal Bearings
Abstract:
Wound field synchronous generators (WFSG) are the standard electromechanical converter for back-up and utility scale power generation. Maintenance costs may be minimized by adopting noncontact or “brushless” technologies to replace sliding slip ring connections for rotor field excitation. This paper presents a brushless excitation approach using ceramic insulated sleeve (journal) bearings with oil lubrication to form capacitively coupled slip rings, in contrast to more traditional inductive brushless exciters and rotary transformers. This capacitive power transfer (CPT) approach exhibits advantages including low weight, low volume, and has a relatively simple construction using off-the-shelf components. Analysis, design, and prototype construction of the CPT system are presented. Experimental results demonstrate that 1.7 nF of capacitive coupling transfers 340 W to the rotor field winding of a 10 kW 208 V WFSG. Voltage regulation of a WFSG is demonstrated during steady state and 1 per unit load step changes yielding a NEMA-MG1 class G2 rating.
Autors: Jiejian Dai;Skyler Hagen;Daniel C. Ludois;Ian P. Brown;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2017, volume: 53, issue:4, pages: 3317 - 3326
Publisher: IEEE
 
» Synchronverters With Better Stability Due to Virtual Inductors, Virtual Capacitors, and Anti-Windup
Abstract:
Synchronverters are inverters that mimic the behavior of synchronous generators. In this paper, we propose five modifications to the synchronverter algorithm from the paper “Synchronverters: Inverters that mimic synchronous generators,” (IEEE Trans. Ind. Electron., vol. 58, no. 4, pp. 1259–1267, Apr. 2011), to improve its stability and performance. These modifications are implemented in software and do not require any changes in the inverter hardware. The first two modifications concern the control of the virtual field current in the synchronverter so that it is more robust to faults. We prove the stability of the grid-connected synchronverter with this improved field current controller. The third modification is to increase the effective size of the filter inductors virtually. This is motivated using results from the stability analysis of a constant field current synchronous generator connected to an ac power grid and also by practical considerations. Simulations and experiments show that this leads to a much better response to changes in grid frequency, voltage, or to imbalance in the grid. The fourth modification is to change the formula for the (virtual) nominal active mechanical torque to take into account the (virtual) losses in the output impedance of the converter. This makes the tracking of the desired active power much more accurate. The fifth modification is to introduce virtual capacitors in series with the inverter outputs to filter spurious dc components from the current supplied to the grid.
Autors: Vivek Natarajan;George Weiss;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2017, volume: 64, issue:7, pages: 5994 - 6004
Publisher: IEEE
 
» Synchrophasor Sensor Networks for Grid Communication and Protection
Abstract:
This paper focuses primarily on leveraging synchronized current/voltage amplitudes and phase angle measurements to foster new categories of applications, such as improving the effectiveness of grid protection and minimizing outage duration for distributed grid systems. The motivation for such an application arises from the fact that with the support of communication, synchronized measurements from multiple sites in a grid network can greatly enhance the accuracy and timeliness of identifying the source of instabilities. The paper first provides an overview of synchrophasor networks and then presents techniques for power quality assessment, including fault detection and protection. To achieve this we present a new synchrophasor data partitioning scheme that is based on the formation of a joint space and time observation vector. Since communication is an integral part of synchrophasor networks, the newly adopted wireless standard for machine-to-machine (M2M) communication, known as IEEE 802.11ah, has been investigated. The paper also presents a novel implementation of a hardware in the loop testbed for real-time performance evaluation. The purpose is to illustrate the use of both hardware and software tools to verify the performance of synchrophasor networks under more realistic environments. The testbed is a combination of grid network modeling, and an Emulab-based communication network. The combined grid and communication network is then used to assess power quality for fault detection and location using the IEEE 39-bus and 390-bus systems.
Autors: Hamid Gharavi;Bin Hu;
Appeared in: Proceedings of the IEEE
Publication date: Jul 2017, volume: 105, issue:7, pages: 1408 - 1428
Publisher: IEEE
 
» Synthesis and Design of a Distributed Inductor
Abstract:
A “distributed inductor” comprises a core containing multiple winding windows carrying prescribed Ampere-turns. Its magnetic field can be shaped to vary by less than a distribution factor υ. The positions, dimensions, and Ampere-turns of the windings are synthesized to improve the energy density. A design procedure is formulated to accentuate the impact of υ on the tradeoffs between inductance and losses. It is validated by a prototype having half the height of the commercial counterpart for a 30 W converter.
Autors: Han Cui;Khai D. T. Ngo;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2017, volume: 64, issue:7, pages: 5351 - 5359
Publisher: IEEE
 
» Synthesis of CIS Quantum Dots in Low-Temperature Regime: Effects of Precursor Composition and Temperature Ramps
Abstract:
Copper Indium Sulfide (CIS) based quantum dots (QDs) have strong potential for future large-scale applications in photovoltaic, display, and optoelectronic sectors, partly due to their minimal toxicity. CIS QDs are usually grown at temperatures over 200 °C. In this work, we present a gram-scale, noninjection synthesis of CIS-based QDs in a low temperature regime and report, through systematic analyses, on the influence of temperature ramping profiles and precursor compositions on the properties of core CIS and core/shell CIS/ZnS QDs. It is established that the temperature ramp method is as important as the peak temperature itself. Nonabrupt temperature ramping results in core CIS QDs with more ligand coverage and fewer defects, and makes ZnS overgrowth possible even with lower Zn:S molar ratios. Precursor level molar ratios of 1:2 for Cu:In and 8:1 for Zn:S resulted in improved efficiency in CIS and CIS/ZnS QDs with strong and long-lived emissions in the 85–245 ns range. Implementing a dropwise addition of the ZnS precursor leads to prolonged QD extraction and shorter emission wavelengths. The different processes showed a wide range of tunability in the visible-to-IR range along with intense photoluminescence. The ZnS shell growth dependence on temperature ramping mode is explained through a mechanism for sulfur consumption, from the core or from the ligands’ thiol groups. The low temperature regime processes, tunability for wide range of emissions, and identified pathways for long-lived emissions make these less-toxic, CIS-based QDs amenable to large area, scaled-up processing for device applications.
Autors: Bahareh Sadeghimakki;Yaxin Zheng;Navid M. S. Jahed;Siva Sivoththaman;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jul 2017, volume: 16, issue:4, pages: 659 - 666
Publisher: IEEE
 
» Synthesis of Predictive Equivalent Consumption Minimization Strategy for Hybrid Electric Vehicles Based on Closed-Form Solution of Optimal Equivalence Factor
Abstract:
Previously, an equivalent consumption minimization strategy (ECMS) was developed that provides near-optimal performance of hybrid vehicles based on an adaptation of equivalence factor from state of charge feedback. However, under real-world driving conditions with uncertainties, such as hilly roads, ECMS requires a predictive scheme utilizing future driving information in order to prevent a loss of optimality. In this paper, we synthesize predictive ECMS in a feedforward way to adjust the equivalence factor based on its theoretical connection with future driving statistics, in a systematic manner. First, a useful noncausal adaptation strategy is extracted from dynamic programming results. Then, the inverse problem is formulated and solved to derive an explicit representation of the constant optimal equivalence factor with justified assumptions. Finally, a causal, predictive adaptation strategy using this closed-form solution is synthesized to mimic the noncausal one, and its effectiveness is evaluated for fuel cell hybrid electric vehicles. Results show that if the predicted statistical information reflects well the future driving conditions, the proposed strategy accurately estimates the constant optimal equivalence factor, including the jump behavior, thereby yielding less than 1.5% loss of fuel optimality. Moreover, this approach is extendible to other configurations.
Autors: Jihun Han;Dongsuk Kum;Youngjin Park;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2017, volume: 66, issue:7, pages: 5604 - 5616
Publisher: IEEE
 
» Synthesis of RuO2 Nanowires by Alkali-Assisted Oxidation of Ruthenium in Plasma Afterglow at Atmospheric Pressure
Abstract:
RuO2 nanowires are synthesized by oxidation of ruthenium thanks to a micro-post-discharge at atmospheric pressure. However, RuO2 nanowires form islands. The growth mechanism depending on surface defects, the surface density of the nanowires is limited. We report on the influence of two alkali salts, NaCl and KCl, deposited as grains on ruthenium to act as defects and increase the nanowire density. These grains induce the growth of RuO 2 nanowires all around them, creating a circular area where nanowires are found. Nanowires start growing at the triple point at the grain base where the alkali-salt grain, ruthenium from the substrate, and oxidizing gaseous species coexist. When nanowires grow, the stress induced in the surrounding layer creates new cracks, making possible the radial propagation of the nanowires. The presence of nanowires on grains is due to the etching mechanism that converts the alkali salt into an oxide, enabling onward oxidation of ruthenium.
Autors: Duclair Kuete Saa;Thomas Gries;Sylvie Migot-Choux;Jaafar Ghanbaja;Pascal Boulet;Samuel Laminsi;Thierry Belmonte;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jul 2017, volume: 16, issue:4, pages: 624 - 633
Publisher: IEEE
 
» Synthetic Aperture Radar Image Synthesis by Using Generative Adversarial Nets
Abstract:
Synthetic aperture radar (SAR) image simulators based on computer-aided drawing models play an important role in SAR applications, such as automatic target recognition and image interpretation. However, the accuracy of such simulators is due to geometric error and simplification in the electromagnetic calculation. In this letter, an end-to-end model was developed that could directly synthesize the desired images from the known image database. The model was based on generative adversarial nets (GANs), and its feasibility was validated by comparisons with real images and ray-tracing results. As a further step, the samples were synthesized at angles outside of the data set. However, the training process of GAN models was difficult, especially for SAR images which are usually affected by noise interference. The major failure modes were analyzed in experiments, and a clutter normalization method was proposed to ameliorate them. The results showed that the method improved the speed of convergence up to 10 times. The quality of the synthesized images was also improved.
Autors: Jiayi Guo;Bin Lei;Chibiao Ding;Yueting Zhang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Jul 2017, volume: 14, issue:7, pages: 1111 - 1115
Publisher: IEEE
 
» System Integration and In Vivo Testing of a Robot for Ultrasound Guidance and Monitoring During Radiotherapy
Abstract:
We are developing a cooperatively controlled robot system for image-guided radiation therapy (IGRT) in which a clinician and robot share control of a 3-D ultrasound (US) probe. IGRT involves two main steps: 1) planning/simulation and 2) treatment delivery. The goals of the system are to provide guidance for patient setup and real-time target monitoring during fractionated radiotherapy of soft tissue targets, especially in the upper abdomen. To compensate for soft tissue deformations created by the probe, we present a novel workflow where the robot holds the US probe on the patient during acquisition of the planning computerized tomography image, thereby ensuring that planning is performed on the deformed tissue. The robot system introduces constraints (virtual fixtures) to help to produce consistent soft tissue deformation between simulation and treatment days, based on the robot position, contact force, and reference US image recorded during simulation. This paper presents the system integration and the proposed clinical workflow, validated by an in vivo canine study. The results show that the virtual fixtures enable the clinician to deviate from the recorded position to better reproduce the reference US image, which correlates with more consistent soft tissue deformation and the possibility for more accurate patient setup and radiation delivery.
Autors: Hasan Tutkun Şen;Muyinatu A. Lediju Bell;Yin Zhang;Kai Ding;Emad Boctor;John Wong;Iulian Iordachita;Peter Kazanzides;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jul 2017, volume: 64, issue:7, pages: 1608 - 1618
Publisher: IEEE
 
» Systematic Constructions of Rotation Symmetric Bent Functions, 2-Rotation Symmetric Bent Functions, and Bent Idempotent Functions
Abstract:
Rotation symmetric bent functions and their generation two-rotation symmetric bent functions are two classes of cryptographically significant Boolean functions. However, few constructions have been presented in the literature, which either have restriction on integer or have algebraic degree no more than 4. In this paper, for any even integer , three classes of bent functions are presented respectively. Most notably, the proposed -variable rotation symmetric bent functions and two-rotation symmetric bent functions can have any possible algebraic degree ranging from 2 to . Besides, we obtain bent idempotent functions with the maximal algebraic degree .
Autors: Sihong Su;Xiaohu Tang;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jul 2017, volume: 63, issue:7, pages: 4658 - 4667
Publisher: IEEE
 
» Takagi–Sugeno Fuzzy Model Based Fault Estimation and Signal Compensation With Application to Wind Turbines
Abstract:
In response to the high demand of the operation reliability by implementing real-time monitoring and system health management, a robust fault estimation and fault-tolerant control approach is proposed for Takagi–Sugeno fuzzy systems in this study, by integrating the augmented system method, unknown input fuzzy observer design, linear matrix inequality optimization, and signal compensation techniques. Specifically, a fuzzy augmented system method is used to construct an augmented plant with the concerned faults and system states being the augmented states. An unknown input fuzzy observer technique is thus utilized to estimate the augmented states and decouple unknown inputs that can be decoupled. A linear matrix inequality approach is further addressed to ensure the global stability of the estimation error dynamics and attenuate the influences from the unknown inputs that cannot be decoupled. As a result, the robust estimates of the concerned faults and system states can be obtained simultaneously. Based on the fault estimates, a signal compensation scheme is developed to remove the effects of the faults on the system dynamics and outputs, leading to a stable dynamic satisfying the expected performance. Finally, the effectiveness of the proposed Takagi–Sugeno model based fault estimation and signal compensation algorithms is demonstrated by a case study on a 4.8-MW wind turbine benchmark system.
Autors: Xiaoxu Liu;Zhiwei Gao;Michael Z. Q. Chen;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Jul 2017, volume: 64, issue:7, pages: 5678 - 5689
Publisher: IEEE
 
» Task Scheduling Techniques for Asymmetric Multi-Core Systems
Abstract:
As performance and energy efficiency have become the main challenges for next-generation high-performance computing, asymmetric multi-core architectures can provide solutions to tackle these issues. Parallel programming models need to be able to suit the needs of such systems and keep on increasing the application’s portability and efficiency. This paper proposes two task scheduling approaches that target asymmetric systems. These dynamic scheduling policies reduce total execution time either by detecting the longest or the critical path of the dynamic task dependency graph of the application, or by finding the earliest executor of a task. They use dynamic scheduling and information discoverable during execution, fact that makes them implementable and functional without the need of off-line profiling. In our evaluation we compare these scheduling approaches with two existing state-of the art heterogeneous schedulers and we track their improvement over a FIFO baseline scheduler. We show that the heterogeneous schedulers improve the baseline by up to 1.45 in a real 8-core asymmetric system and up to 2.1 in a simulated 32-core asymmetric chip.
Autors: Kallia Chronaki;Alejandro Rico;Marc Casas;Miquel Moretó;Rosa M. Badia;Eduard Ayguadé;Jesus Labarta;Mateo Valero;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Jul 2017, volume: 28, issue:7, pages: 2074 - 2087
Publisher: IEEE
 
» TDM-PON for Accommodating TDD-Based Fronthaul and Secondary Services
Abstract:
A time division multiplexing-passive optical network (TDM-PON) has been attracting attention with a view to realizing the cost-effective mobile fronthaul (MFH) of a mobile base station (BS). A cost-effective MFH is needed because a lot of BSs will be densely deployed in fifth generation mobile networks (5G). A TDM-PON is capable of reducing the network cost as the number of subscribers increases. However, the number of remote radio heads that can be accommodated in a TDM-PON is limited since a 5G MFH has a throughput of more than 1 Gbps. The accommodation of not only the MFH but also multiple services will enable us to construct a more cost-effective network that will in turn achieve cost-effective 5G MFH. Therefore, we propose the accommodation of the fronthaul and secondary services in a TDM-PON. Our proposed TDM-PON allows us to increase the number of accommodated ONUs. We use a traffic monitor to capture the MFH signal and then estimate the unallocated interval in the PON domain by using the characteristics of the MFH signal. The signals of the secondary services are inserted in the unallocated interval of the MFH signal. We estimate the unallocated interval by using this characteristic. In this paper, we report experimental and the theoretical results for our proposed technique obtained with a 10 Gigabit-Ethernet PON prototype. Moreover, we also discuss the variation in throughput when we increase the number of ONUs.
Autors: Daisuke Hisano;Takayuki Kobayashi;Hiroshi Ou;Tatsuya Shimada;Hiroyuki Uzawa;Jun Terada;Akihiro Otaka;
Appeared in: Journal of Lightwave Technology
Publication date: Jul 2017, volume: 35, issue:14, pages: 2788 - 2796
Publisher: IEEE
 
» Technical Activities ? Our Core Function [President's Message]
Abstract:
Presents the President’s message for this issue of the publication.
Autors: Tomy Sebastian;
Appeared in: IEEE Industry Applications Magazine
Publication date: Jul 2017, volume: 23, issue:4, pages: 4 - 5
Publisher: IEEE
 
» Technological distraction
Abstract:
I can’t help it. My attention span has shrunk alarmingly, and I’m easily distracted. Worse, I seem to look for and welcome distractions. I should be focusing my attention on the task at hand, which is writing this small essay. Instead I keep checking the Internet with my smartphone. I look around me at this coffee shop and everyone seems to be staring at their cellphones. I don’t think we used to be like this, and I wonder: Has technology done this to us, and if so, is this bad or good?
Autors: Robert W. Lucky;
Appeared in: IEEE Spectrum
Publication date: Jul 2017, volume: 54, issue:7, pages: 25 - 25
Publisher: IEEE
 
» Temperature-Aware Dynamic Voltage Scaling to Improve Energy Efficiency of Near-Threshold Computing
Abstract:
Power and energy reduction is of uttermost importance for applications with stringent power/energy budget such as ultralow power and energy-harvested systems. Aggressive voltage scaling and in particular near-threshold computing is a promising approach to reduce the power and energy consumption. However, reducing the supply voltage leads to drastic performance variation induced by process and runtime variation. Temperature variation is one of the major sources of performance variation. In this paper, we study the impact of temperature variation on the circuit behavior in the near-threshold voltage region and show that the ambient temperature has a huge impact on the metrics such as circuit delay, power, and energy consumption. We also propose a low-cost, ambient temperature-aware voltage scaling technique to reduce the unnecessary energy overhead caused by temperature variation. Simulation results show that our proposed approach reduces the energy consumption by more than .
Autors: Saman Kiamehr;Mojtaba Ebrahimi;Mohammad Saber Golanbari;Mehdi B. Tahoori;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Jul 2017, volume: 25, issue:7, pages: 2017 - 2026
Publisher: IEEE
 
» Temperature-Dependent Access Resistances in Large-Signal Modeling of Millimeter-Wave AlGaN/GaN HEMTs
Abstract:
In this paper, a new method for the separate extraction of the temperature-dependent source () and drain () access resistances in gallium nitride (GaN) high electron-mobility transistors (HEMTs) by using the definition of access resistances is reported. Based on this method, the temperature-dependent access resistances (TDARs) of a gate-length GaN HEMT with unequal gate-source and gate-drain distance are extracted. By integrating the extracted access resistances into a modified Angelov model, the effects of TDARs on millimeter-wave (mmW) large-signal performance of the GaN HEMT at different ambient temperatures (i.e., −55 °C, 25 °C, and 85 °C) are investigated. Moreover, the influence of temperature coefficient difference between and due to the asymmetry of the device has been also revealed. The results show that the TDARs have large impact on the large-signal modeling of mmW GaN HEMTs, and the temperature coefficients of and need to be considered separately in the modeling of asymmetric GaN HEMTs. The proposed TDARs extraction method would be useful for accurate modeling of GaN HEMTs at mmW frequencies.
Autors: Xiaodong Zhao;Yuehang Xu;Yonghao Jia;Yunqiu Wu;Ruimin Xu;Jingqiang Li;Zhifu Hu;Hongjiang Wu;Wei Dai;Shujun Cai;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Jul 2017, volume: 65, issue:7, pages: 2271 - 2278
Publisher: IEEE
 
» Temporal Learning Using Second-Order Memristors
Abstract:
Utilizing internal dynamic processes in memristors may allow the devices to process temporal data natively. In this letter, we show the ability of second-order memristors to process information in the time domain, and discuss a memristive STDP network that can learn and classify temporal as well as classical data patterns.
Autors: Mohammed A. Zidan;YeonJoo Jeong;Wei D. Lu;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Jul 2017, volume: 16, issue:4, pages: 721 - 723
Publisher: IEEE
 
» Tensor-Based Efficient Multi-Interferer RFI Excision Algorithms for SIMO Systems
Abstract:
Radio frequency interference (RFI) is causing performance loss in microwave radiometry, radio astronomy, and satellite communications. As the number of interferers increases, the performance loss gets more severe and RFI excision becomes more difficult. In this regard, this paper introduces the multilinear algebra framework to the multi-interferer RFI (MI-RFI) excision research by proposing a multi-linear subspace estimation and projection (MLSEP) algorithm for single-input multiple-output (SIMO) systems suffering from MI-RFI. Having employed smoothed observation windows, a smoothed MLSEP (s-MLSEP) algorithm, which enhances MLSEP, is also proposed. MLSEP and s-MLSEP require the knowledge of the number of interferers and their respective channel order. Accordingly, a novel smoothed matrix-based joint number of interferers and channel order enumerator is proposed. Performance analyses corroborate that both MLSEP and s-MLSEP can excise all interferers when the perturbations get infinitesimally small. For such perturbations, the analyses also attest that s-MLSEP exhibit a faster convergence to a zero excision error than MLSEP which, in turn converges faster than a subspace projection algorithm. Despite its slight complexity, simulations and performance assessment on real-world data demonstrate that MLSEP outperforms projection-based RFI excision algorithms. Simulations also corroborate that s-MLSEP outperforms MLSEP as the smoothing factor gets smaller.
Autors: Tilahun Melkamu Getu;Wessam Ajib;Omar A. Yeste-Ojeda;
Appeared in: IEEE Transactions on Communications
Publication date: Jul 2017, volume: 65, issue:7, pages: 3037 - 3052
Publisher: IEEE
 
» Terahertz Communication for Vehicular Networks
Abstract:
With the never-ending increase in the number of mobile connected devices and the need for higher data rates anywhere, anytime, higher frequency bands are being considered for communications. As millimeter-wave technology moves from research to commercial deployments, and motivated by the still limited bandwidth, the terahertz (THz) band is envisioned as the next frontier for communications. When it comes to vehicular networks, communication at much higher frequencies and, consequently, with much higher data rates brings many exciting opportunities as well as challenges. In this paper, an overview of the opportunities and challenges in THz communications for vehicular networks is provided. In addition, the papers in this Special Section which provide first-time solutions to some of these challenges, are introduced.
Autors: Shahid Mumtaz;Josep Miquel Jornet;Jocelyn Aulin;Wolfgang H. Gerstacker;Xiaodai Dong;Bo Ai;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Jul 2017, volume: 66, issue:7, pages: 5617 - 5625
Publisher: IEEE
 
» Terrestrial Laser Scanning-Based Deformation Analysis for Arch and Beam Structures
Abstract:
Nowadays, with the assistance of the high accuracy terrestrial laser scanning (TLS) measurement techniques, the mechanics analysis of structures could be better understood. This paper has a comparative analysis of arch and beam structures in terms of deformation behavior in loading experiments. The goal of this paper is to discover the potential value of the different structures in the architecture through the investigation of the anti-load capacity of the arch and beam structures. This paper is focused on the comparison of load-displacement relation between arch and beam with static load experiment, which is based on TLS techniques and surface analysis method. The innovation is that we try to reveal the partial area changing rules named “partial area analysis,” which is a new method to investigate the deformation behavior of structure. It is exposed that both arch and beam structures in the loading progress would suffer three stages, which are steady, developing, and fracture. Furthermore, considering the effect of pre-stress, steady stage would last longer, and developing and fracture stages would be hysteretic.
Autors: Hao Yang;Xiangyang Xu;Wei Xu;Ingo Neumann;
Appeared in: IEEE Sensors Journal
Publication date: Jul 2017, volume: 17, issue:14, pages: 4605 - 4611
Publisher: IEEE
 
» Test Results for a High Temperature Non-Permanent-Magnet Traction Motor
Abstract:
Non-permanent-magnet machines are generally known to be less power dense than permanent magnet counterparts, but the absence of permanent magnets in these machines makes them well suited for high temperature applications. This offers a degree of freedom in improving their power density, because they can operate at higher electrical loading while maintaining acceptable efficiency. This paper presents a high temperature dc-biased reluctance machine that is structurally similar to a conventional switched reluctance machine. This non-permanent-magnet machine has a dc field winding and an ac three-phase armature winding. The machine is equipped with a high temperature 280 °C rated insulation system. Test results showing machine performance under continuous operation against the FreedomCar 2020 specifications as well as at high temperature up to 280 °C are presented. Compared with an initial design using conventional insulation designed for operation at 200 °C, the high temperature insulation system enabled the machine to operate at twice the temperature rise and achieve 43% increase in power.
Autors: Tsarafidy Raminosoa;Ayman M. El-Refaie;David A. Torrey;Kevin Grace;Di Pan;Stefan Grubic;Karthik Bodla;Kum-Kang Huh;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Jul 2017, volume: 53, issue:4, pages: 3496 - 3504
Publisher: IEEE
 
» Testing - A Method to Confirm Compliance with a Standard [Standards]
Abstract:
Discusses the importance of designing products that are safe for consumers. Reports on the initiatives of the U.S Dept. of Labor's Occupational Safety and Health Administration (OSHA) to ensure that these safety measures are enforced through product labeling.
Autors: Daleep Mohla;
Appeared in: IEEE Industry Applications Magazine
Publication date: Jul 2017, volume: 23, issue:4, pages: 86 - 90
Publisher: IEEE
 
» The 2015 Ukraine Blackout: Implications for False Data Injection Attacks
Abstract:
In a false data injection attack (FDIA), an adversary stealthily compromises measurements from electricity grid sensors in a coordinated fashion, with a view to evading detection by the power system bad data detection module. A successful FDIA can cause the system operator to perform control actions that compromise either the physical or economic operation of the power system. In this letter, we consider some implications for FDIAs arising from the late 2015 Ukraine Blackout event.
Autors: Gaoqi Liang;Steven R. Weller;Junhua Zhao;Fengji Luo;Zhao Yang Dong;
Appeared in: IEEE Transactions on Power Systems
Publication date: Jul 2017, volume: 32, issue:4, pages: 3317 - 3318
Publisher: IEEE
 
» The 2016 MTT-S Undergraduate\/Pregraduate Scholarship Awardees [Education News]
Abstract:
Presents the recipients of the MTT-S Undergraduate/Pregraduate Student Scholarship Awards.
Autors: Zlatica Marinković;Ping Jack Soh;Ramesh K. Gupta;
Appeared in: IEEE Microwave Magazine
Publication date: Jul 2017, volume: 18, issue:5, pages: 115 - 119
Publisher: IEEE
 
» The 2017 MTT-S Graduate Student Fellowship Awards [Education News]
Abstract:
Presents the recipients of the MTT-S Graduate Student Fellowship Awards.
Autors: Giovanni Crupi;Roger Kaul;Changzhi Li;Ramesh K. Gupta;
Appeared in: IEEE Microwave Magazine
Publication date: Jul 2017, volume: 18, issue:5, pages: 110 - 114
Publisher: IEEE
 
» The Binary Energy Harvesting Channel With a Unit-Sized Battery
Abstract:
We consider a binary energy harvesting communication channel with a finite-sized battery at the transmitter. In this model, the channel input is constrained by the available energy at each channel use, which is driven by an external energy harvesting process, the size of the battery, and the previous channel inputs. We consider an abstraction where energy is harvested in binary units and stored in a battery with the capacity of a single unit, and the channel inputs are binary. Viewing the available energy in the battery as a state, this is a state-dependent channel with input-dependent states, memory in the states, and causal state information available at the transmitter only. We find an equivalent representation for this channel based on the timings of the symbols, and determine the capacity of the resulting equivalent timing channel via an auxiliary random variable. We present achievable rates based on certain selections of this auxiliary random variable, which resemble lattice coding for the timing channel. We develop upper bounds for the capacity by using a genie-aided method, and also by quantifying the leakage of the state information to the receiver. We show that the proposed achievable rates are asymptotically capacity achieving for small energy harvesting rates. We extend the results to the case of ternary channel inputs. We numerically observe that our achievable rates are notably close to the upper bounds, and outperform basic Shannon strategies that only consider instantaneous battery states, for all parameter values.
Autors: Kaya Tutuncuoglu;Omur Ozel;Aylin Yener;Sennur Ulukus;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jul 2017, volume: 63, issue:7, pages: 4240 - 4256
Publisher: IEEE
 
» The Capacity of Private Information Retrieval
Abstract:
In the private information retrieval (PIR) problem, a user wishes to retrieve, as efficiently as possible, one out of messages from non-communicating databases (each holds all messages) while revealing nothing about the identity of the desired message index to any individual database. The information theoretic capacity of PIR is the maximum number of bits of desired information that can be privately retrieved per bit of downloaded information. For messages and databases, we show that the PIR capacity is . A remarkable feature of the capacity achieving scheme is that if we eliminate any subset of messages (by setting the message symbols to zero), the resulting scheme also achieves the PIR capacity for the remaining subset of messages.
Autors: Hua Sun;Syed Ali Jafar;
Appeared in: IEEE Transactions on Information Theory
Publication date: Jul 2017, volume: 63, issue:7, pages: 4075 - 4088
Publisher: IEEE
 
» The coin-op computer [Past Forward]
Abstract:
In 1973, a group of computer enthusiasts called Loving Grace Cybernetics began setting up terminals like this one in Berkeley, Calif. Each terminal connected by modem to a remote computer that hosted an electronic bulletin board, which members of the public were invited to use as a “community memory.” Reading the bulletin board was free, but posting a listing cost a quarter. Listings covered a range of practical matters: apartment rentals, music lessons, and where to find a decent bagel.
Autors: David C. Brock;
Appeared in: IEEE Spectrum
Publication date: Jul 2017, volume: 54, issue:7, pages: 52 - 52
Publisher: IEEE
 
» The Development of a Thin-Filmed Noninvasive Tissue Perfusion Sensor to Quantify Capillary Pressure Occlusion of Explanted Organs
Abstract:
A new thin-filmed perfusion sensor was developed using a heat flux gauge, thin-film thermocouple, and a heating element. This sensor, termed “CHFT+,” is an enhancement of the previously established combined heat flux–temperature (CHFT) sensor technology predominately used to quantify the severity of burns [1]. The CHFT+ sensor was uniquely designed to measure tissue perfusion on explanted organs destined for transplantation, but could be functionalized and used in a wide variety of other biomedical applications. Exploiting the thin and semiflexible nature of the new CHFT+ sensor assembly, perfusion measurements can be made from the underside of the organ—providing a quantitative indirect measure of capillary pressure occlusion. Results from a live tissue test demonstrated, for the first time, the effects of pressure occlusion on an explanted porcine kidney. CHFT+ sensors were placed on top of and underneath 18 kidneys to measure and compare perfusion at perfusate temperatures of 5 and 20 °C. The data collected show a greater perfusion on the topside than the underside of the specimen for the length of the experiment. This indicates that the pressure occlusion is truly affecting the perfusion, and, thus, the overall preservation of explanted organs. Moreover, the results demonstrate the effect of preservation temperature on the tissue vasculature. Focusing on the topside perfusion only, the 20 °C perfusion was greater than the 5 °C perfusion, likely due to the vasoconstrictive response at the lower perfusion temperatures.
Autors: Timothy J. O'Brien;Ali R. Roghanizad;Philip A. Jones;Charles H. Aardema;John L. Robertson;Thomas E. Diller;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Jul 2017, volume: 64, issue:7, pages: 1631 - 1637
Publisher: IEEE
 
» The Effect of Motion-Induced Eddy Current on Circumferential Magnetization in MFL Testing for a Steel Pipe
Abstract:
Eddy current effect essentially occurs when a relative movement happens between steel pipes and the circumferential magnetizer in high-speed magnetic flux leakage (MFL) testing. To improve the MFL testing for longitudinal defects, the effect of motion-induced eddy current (MIEC) on circumferential magnetization is analyzed. First, in terms of Maxwell equations, the eddy current effect and the MIEC distribution in the steel pipe are analyzed. Then, the finite-element simulations are conducted to investigate the MIEC distribution, the magnetization status change, and the sensitivity difference. With the rotational speed increasing, the MIEC and circumferential magnetic flux density gradually become asymmetrical and non-uniform. The MFL testing signal amplitudes of external and internal defects in the arriving and leaving parts change in different variation trends. Finally, the relevant high-speed MFL testing experiments for steel pipes are performed to confirm the effect of MIEC. The experimental results match well with the theoretical analysis and numerical simulation results.
Autors: Jianbo Wu;Yanhua Sun;Bo Feng;Yihua Kang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Jul 2017, volume: 53, issue:7, pages: 1 - 6
Publisher: IEEE
 

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