Electrical and Electronics Engineering publications abstract of: 05-2017 sorted by title, page: 6

» Development and Testing of ZnO Nanorods Based Biosensor on Model Gram-Positive and Gram-Negative Bacteria
Abstract:
Water is a basic human need, but many people do not have access to clean and safe drinking water. Many people die of waterborne bacterial diseases in the world. The presence of bacterial pathogens in water can be detected by using sophisticated and expensive instruments, which take extensive time for measurement. In contrast to those instrumentation, nanostructure-based devices can be used as instant and cheap bacteria sensors. This paper reports the fabrication of a sensor using ZnO nanorods for detection of two bacterial pathogens, namely Escherichia coli, which is a gram-negative bacteria and Streptococcus pneumonia, which is a gram-positive bacteria present in water at different concentrations. The fabrication of the sensor was done by growing ZnO nanorods hydrothermally on a Cu electrode. The sensor was then tested with some known concentrations of bacteria mixed in water. When bacteria mixed water sample is dropped over the sensor, the electrical resistance of the sensor varies proportionally with bacteria concentration. Maximum responses of 96% and 94.375% at room temperature and minimum detection limits of 1.12% and 1.01% were achieved for cells/mL of E. coli and cells/mL of S. pneumonia present in water, respectively. The high sensitivity and dynamic repeatability exhibited by these sensors reveal that ZnO nanorods are promising as sensitive and reliable sensors for detecting bacteria present in water.
Autors: Rashi Borgohain;Sunandan Baruah;
Appeared in: IEEE Sensors Journal
Publication date: May 2017, volume: 17, issue:9, pages: 2649 - 2653
Publisher: IEEE
 
» Development of a Parallel Version of PhyML 3.0 Using Shared Memory
Abstract:
This work presents the main steps towards a parallel version of the open source phylogenetic tree reconstruction software PhyML 3.0, which uses the method of maximum likelihood in phylogenetic reconstruction process. The PhyML was parallelized by a shared memory approach (using OpenMP) and at the same time using the version already consolidated in PhyML 3.0, the version passing messages with distributed memory (using MPI), was also constructed a version hybrid (MPI and OpenMP) of PhyML. The tests for the efficiency and speedup were carried out in a cluster of two ways, the first only by analyzing the performance version with OpenMP (DNA and proteins) and the second making a comparative analysis of the performance of three parallel versions (OpenMP, MPI and Hybrid) using DNA data only. The results obtained show speedup of approximately six to 8 cores on 1 server, which allows the use of this code problems that require a lot of time in the serial version, front the need or urgent of the fast processing of data.
Autors: Julio Oliveira da Silva;Esbel Tomas Valero Orellana;Martha Ximena Torres Delgado;
Appeared in: IEEE Latin America Transactions
Publication date: May 2017, volume: 15, issue:5, pages: 959 - 967
Publisher: IEEE
 
» Development of an Acoustic Levitation Linear Transportation System Based on a Ring-Type Structure
Abstract:
A linear acoustic levitation transportation system based on a ring-type vibrator is presented. The system is composed by two 21-kHz Langevin transducers connected to a ring-shaped structure formed by two semicircular sections and two flat plates. In this system, a flexural standing wave is generated along the ring structure, producing an acoustic standing wave between the vibrating ring and a plane reflector located at a distance of approximately a half wavelength from the ring. The acoustic standing wave in air has a series of pressure nodes, where small particles can be levitated and transported. The ring-type transportation system was designed and analyzed by using the finite element method. Additionally, a prototype was built and the acoustic levitation and transport of a small polystyrene particle was demonstrated.
Autors: Gilles P. L. Thomas;Marco A. B. Andrade;Julio Cezar Adamowski;Emílio Carlos Nelli Silva;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: May 2017, volume: 64, issue:5, pages: 839 - 846
Publisher: IEEE
 
» Development of epoxy flux for lead-free solder [News from Japan]
Abstract:
Following global trends and international agreements, there is a growing conviction that toxic materials, which are potential health risks, should be eliminated as far as possible from widely used products, even if they lead to superior product characteristics. Thus there is an agreement called RoHS or WEEE within the European Union that bans import or sale of products that contain substances hazardous to human health or the environment. Lead (Pb) is one such hazardous material. Conventional solder used to bond electric wires or conductors contains Pb,and a flux, of which the main component is rosin (derived from turpentine oil), has been for many years combined with conventional solder. However, a new flux more suitable for Pb-free solder must now be developed.
Autors: Y. Ohki;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: May 2017, volume: 33, issue:3, pages: 39 - 41
Publisher: IEEE
 
» Development of INS/GNSS UAV-Borne Vector Gravimetry System
Abstract:
An airborne gravimetry system consisting of an inertial navigation system (INS) and a global navigation satellite system (GNSS) has been proven to perform well in gravity observation. The system is also more cost- or time-effective than satellite missions and terrestrial gravimeters. In this letter, an unmanned aerial vehicle has been developed as a platform to carry the INS/GNSS vector gravimetry system using an unmanned helicopter. In addition to the kinematic mode, the unmanned helicopter can perform the zero velocity update (ZUPT) mode, which is a novel method in the acquisition of gravity. Results show that the accuracies of the horizontal and vertical gravity disturbance from the kinematic mode at crossover points are approximately 6–11 and 4 mGal, respectively, with a 0.5-km resolution. The accuracy of the repeatability in ZUPT mode is evaluated with the accuracies of approximately 2–3 mGal.
Autors: Cheng-An Lin;Kai-Wei Chiang;Chung-Yen Kuo;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: May 2017, volume: 14, issue:5, pages: 759 - 763
Publisher: IEEE
 
» Development of Silicon Nanowire-Based NEMS Absolute Pressure Sensor Through Surface Micromachining
Abstract:
This letter reports on a nano-electro-mechanical system (NEMS) pressure sensor with p-doped silicon nanowires (average cross-sectional area ~100 nm2) as piezoresistive sensing elements. Taking advantage of surface micromachining, an absolute pressure-sensing device is developed using front-side isotropic etching. In contrast to the previously reported silicon nanowire (SiNW) pressure sensor processed with bulk micromachining through the backside deep reactive ion etching (DRIE), nonlinearity has been reduced to 0.31% (BFSL). In addition, the performance variations across the wafer have been significantly reduced to 6% in comparison with a 33% sensitivity fluctuation across the 8-inch wafer reported in our early work fabricated by a DRIE process. After front-side vacuum sealing, temperature-induced performance degradation has also been minimized. Moreover, the dramatic geometry downsizing (device footprint ) validates the scalability of the SiNW-based NEMS sensor. With excellent uniformity, the SiNW-based sensor can be commercially manufactured on an 8-inch wafer at lower cost with high yield.
Autors: Songsong Zhang;Liang Lou;Yuandong Alex Gu;
Appeared in: IEEE Electron Device Letters
Publication date: May 2017, volume: 38, issue:5, pages: 653 - 656
Publisher: IEEE
 
» Device-Free Counting via Wideband Signals
Abstract:
Counting people and things (targets) in a monitored area, also known as crowd-counting, enables several applications in diverse scenarios, including smart building, intelligent transportation, and public safety. In many scenarios, device-free systems relying on the signal backscattering from targets are preferred to device-based systems relying on the communication with the targets via dedicated or personal devices. However, the use of conventional radar techniques (e.g., for multi-target detection) requires us to associate a different set of measured data with each detected target. Data association is a redundant operation for counting and results in high complexity even with few targets. The need of lower dimensionality and complexity calls for signal features to associate the measured signals directly with the number of targets. This paper proposes a mathematical framework for the design of device-free counting systems. First, a maximum a posteriori algorithm is developed for counting via wideband signal backscattering by relying on model order selection. Then, a method that relies on low-level features is proposed to lower the computational complexity. The proposed method is verified via sample-level simulations in realistic operating conditions and compared with current solutions.
Autors: Stefania Bartoletti;Andrea Conti;Moe Z. Win;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: May 2017, volume: 35, issue:5, pages: 1163 - 1174
Publisher: IEEE
 
» Device-Free Human Activity Recognition Using Commercial WiFi Devices
Abstract:
Since human bodies are good reflectors of wireless signals, human activities can be recognized by monitoring changes in WiFi signals. However, existing WiFi-based human activity recognition systems do not build models that can quantify the correlation between WiFi signal dynamics and human activities. In this paper, we propose a Channel State Information (CSI)-based human Activity Recognition and Monitoring system (CARM). CARM is based on two theoretical models. First, we propose a CSI-speed model that quantifies the relation between CSI dynamics and human movement speeds. Second, we propose a CSI-activity model that quantifies the relation between human movement speeds and human activities. Based on these two models, we implemented the CARM on commercial WiFi devices. Our experimental results show that the CARM achieves recognition accuracy of 96% and is robust to environmental changes.
Autors: Wei Wang;Alex X. Liu;Muhammad Shahzad;Kang Ling;Sanglu Lu;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: May 2017, volume: 35, issue:5, pages: 1118 - 1131
Publisher: IEEE
 
» Diagnostic of Insulators of Conventional Grid Through LabVIEW Analysis of FFT Signal Generated from Ultrasound Detector
Abstract:
This article is intended to present an evaluation on the automation capability in the analysis of insulators of conventional grid by processing the signals generated by ultrasound detectors. The insulators analyzed were removed from the electrical system in various conditions, as well as new insulators. The methodology adopted was a practical analysis of qualitative and quantitative way. The audible noise generated by the output of ultrasound equipment is connected to a personal computer to obtain the FFT signal through LabVIEW software. The characteristic of the FFT signal is used to classify inspected components online, allowing for quick and precise procedure, as shown in the results obtained in this study.
Autors: Stefano Frizzo Stefenon;Joaquim Rodrigo de Oliveira;Antonio Sergio Coelho;Luiz Henrique Meyer;
Appeared in: IEEE Latin America Transactions
Publication date: May 2017, volume: 15, issue:5, pages: 884 - 889
Publisher: IEEE
 
» Diamond Tiling: Tiling Techniques to Maximize Parallelism for Stencil Computations
Abstract:
Most stencil computations allow tile-wise concurrent start, i.e., there always exists a face of the iteration space and a set of tiling directions such that all tiles along that face can be started concurrently. This provides load balance and maximizes parallelism. However, existing automatic tiling frameworks often choose hyperplanes that lead to pipelined start-up and load imbalance. We address this issue with a new tiling technique, called diamond tiling, that ensures concurrent start-up as well as perfect load-balance whenever possible. We first provide necessary and sufficient conditions for a set of tiling hyperplanes to allow concurrent start for programs with affine data accesses. We then provide an approach to automatically find such hyperplanes. Experimental evaluation on a 12-core Intel Westmere shows that diamond tiled code is able to outperform a tuned domain-specific stencil code generator by 10 to 40 percent, and previous compiler techniques by a factor of 1.3 to 10.1.
Autors: Uday Bondhugula;Vinayaka Bandishti;Irshad Pananilath;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: May 2017, volume: 28, issue:5, pages: 1285 - 1298
Publisher: IEEE
 
» Differential 3D Scanning
Abstract:
During the creative process, designers use various techniques and strategies to move from the abstract to the concrete, utilizing different physical and virtual means to represent form. The changes between virtual and physical models are not always fluent, however. Differential 3D scanning can detect the differences between a scanned model (point cloud) and a reference model (polygon mesh or CAD model) and then reflect those changes in the reference model. This can save designers time by reconstructing only the small changed regions rather than the entire object.
Autors: Ammar Hattab;Ian Gonsher;Daniel Moreno;Gabriel Taubin;
Appeared in: IEEE Computer Graphics and Applications
Publication date: May 2017, volume: 38, issue:3, pages: 43 - 51
Publisher: IEEE
 
» Differential Evolution Based on Self-Adaptive Fitness Function for Automated Test Case Generation
Abstract:
Testing is one of the most important parts of the software process, which aims at detecting software faults/bugs and thus guarantees the quality of the final product. Its expense is nearly half of the total cost of software development [7], [9]. Most of the current approaches to software testing are manual, but it has been recently suggested [1] that automated testing should be done to save human resources and budget, as well as to produce high-quality software.
Autors: Han Huang;Fangqing Liu;Xiaoyan Zhuo;Zhifeng Hao;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: May 2017, volume: 12, issue:2, pages: 46 - 55
Publisher: IEEE
 
» Digit-Level Serial-In Parallel-Out Multiplier Using Redundant Representation for a Class of Finite Fields
Abstract:
Two digit-level finite field multipliers in using redundant representation are presented. Embedding in cyclotomic field causes a certain amount of redundancy and consequently performing field multiplication using redundant representation would require more hardware resources. Based on a specific feature of redundant representation in a class of finite fields, two new multiplication algorithms along with their pertaining architectures are proposed to alleviate this problem. Considering area-delay product as a measure of evaluation, it has been shown that both the proposed architectures considerably outperform existing digit-level multipliers using the same basis. It is also shown that for a subset of the fields, the proposed multipliers are of higher performance in terms of area-delay complexities among several recently proposed optimal normal basis multipliers. The main characteristics of the postplace&route application specific integrated circuit implementation of the proposed multipliers for three practical digit sizes are also reported.
Autors: Parham Hosseinzadeh Namin;Roberto Muscedere;Majid Ahmadi;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: May 2017, volume: 25, issue:5, pages: 1632 - 1643
Publisher: IEEE
 
» Digitally Assisted Analog Interference Cancellation for In-Band Full-Duplex Radios
Abstract:
In this letter, a digitally assisted analog interference cancellation architecture is proposed for the prevailing full-duplex radios, which simultaneously transmit and receive signals on the same carrier frequency. An auxiliary transmit chain is deployed to generate a canceling signal and subtract from the self-interference (SI) signal at the receiver front end to prevent saturating the analog-to-digital converter. To ensure the canceling signal a close approximation of the SI signal, an observation chain is used to extract the transmitter response. Correspondingly, a two-step modeling process is inserted to the auxiliary transmit chain to recover both the nonlinear behavior and the multi-path channel between the transmit and receive chains. Experimental results have validated the superior performance of this architecture, particularly for transmitters of high output power and strong nonlinear distortions.
Autors: Ying Liu;Xin Quan;Wensheng Pan;Youxi Tang;
Appeared in: IEEE Communications Letters
Publication date: May 2017, volume: 21, issue:5, pages: 1079 - 1082
Publisher: IEEE
 
» Dimensionality Reduction and Classification of Hyperspectral Images Using Ensemble Discriminative Local Metric Learning
Abstract:
The high-dimensional data space of hyperspectral images (HSIs) often result in ill-conditioned formulations, which finally leads to many of the high-dimensional feature spaces being empty and the useful data existing primarily in a subspace. To avoid these problems, we use distance metric learning for dimensionality reduction. The goal of distance metric learning is to incorporate abundant discriminative information by reducing the dimensionality of the data. Considering that global metric learning is not appropriate for all training samples, this paper proposes an ensemble discriminative local metric learning (EDLML) algorithm for HSI analysis. The EDLML algorithm learns robust local metrics from both the training samples and the relative neighborhood of them and considers the different local discriminative distance metrics by dealing with the data region by region. It aims to learn a subspace to keep all the samples in the same class are as near as possible, while those from different classes are separated. The learned local metrics are then used to build an ensemble metric. Experiments on a number of different hyperspectral data sets confirm the effectiveness of the proposed EDLML algorithm compared with that of the other dimension reduction methods.
Autors: Yanni Dong;Bo Du;Liangpei Zhang;Lefei Zhang;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: May 2017, volume: 55, issue:5, pages: 2509 - 2524
Publisher: IEEE
 
» Direct Estimation of Land Surface Albedo From Simultaneous MISR Data
Abstract:
The availability of multiangular information from the NASA Multi-angle Imaging SpectroRadiometer (MISR) instrument provides an excellent opportunity for the characterization of surface anisotropy, which can be used for improving surface albedo estimation. However, the MISR data have been reported with large uncertainties and data gaps due to inaccurate aerosol estimation and/or cloud masking limiting its otherwise broader applications. To mitigate these issues, two approaches were proposed to estimate land surface albedo directly from surface reflectance (LSA_sfc) and Top-of-Atmosphere reflectance (LSA_toa), respectively. As a further development of the traditional albedo algorithms, this is the first attempt to simultaneously utilize multispectral and multiangular information in surface albedo estimation without any prior constraining information. Validations at AmeriFlux sites show that the proposed algorithms can achieve accuracies similar to that of the MISR product with respective bias and RMSE of 0.004 and 0.032 for LSA_sfc and 0.005 and 0.032 for LSA_toa algorithms. We found that the LSA_toa algorithm can significantly reduce data gaps and provide accurate surface albedo retrievals with two to three times more valid data than the current MISR product. In addition, these approaches can be easily applied to other optical sensors to produce accurate and gap-free clear-sky surface albedo estimations. The results of this paper also highlight the importance of having two to three simultaneous observations with sufficient angular sampling, which can improve albedo accuracy and reduce data gaps.
Autors: Tao He;Shunlin Liang;Dongdong Wang;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: May 2017, volume: 55, issue:5, pages: 2605 - 2617
Publisher: IEEE
 
» Direct Torque Control Scheme for DC Voltage Regulation of the Standalone DFIG-DC System
Abstract:
This paper deals with a standalone doubly fed induction generator-direct current (DFIG-dc) system, where stator and rotor are connected to an isolated dc load, via diode rectifier and voltage-source inverter, respectively. A direct torque control scheme is proposed for dc voltage regulation, where the dc voltage is regulated by a torque controller, while stator frequency is maintained at a nearly rated frequency, by achieving constant dc voltage to rotor flux ratio. An innovative switching strategy is developed to incorporate the phase sequence change in rotor current from subsynchronous speed to supersynchronous speed. Variable switching due to a hysteresis controller provides a reduction in the harmonic content of stator current. This control is simple in implementation, and less parameter dependent. There is no requirement of exact position sensing, while the speed measurement is sufficient, which also reduces the cost and maintenance of an accurate position sensor. Sensing of stator voltage and current is not required in this scheme, and control is done with a minimum number of sensors. As the number of turns on the stator is higher than the rotor, to have common dc link and to exploit rated stator MMF, roles of stator and rotor are interchanged. Performance of the control scheme is verified experimentally on a 4 kW DFIG, and results are reported.
Autors: Akhila Gundavarapu;Himanshu Misra;Amit Kumar Jain;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 3502 - 3512
Publisher: IEEE
 
» Discrete Adjoint Sensitivity Analysis of Hybrid Dynamical Systems With Switching
Abstract:
Sensitivity analysis is an important tool for describing power system dynamic behavior in response to parameter variations. It is a central component in preventive and corrective control applications. The existing approaches for sensitivity calculations, namely, finite-difference and forward sensitivity analysis, require a computational effort that increases linearly with the number of sensitivity parameters. In this paper, we investigate, implement, and test a discrete adjoint sensitivity approach whose computational effort is effectively independent of the number of sensitivity parameters. The proposed approach is highly efficient for calculating sensitivities of larger systems and is consistent, within machine precision, with the function whose sensitivity we are seeking. This is an essential feature for use in optimization applications. Moreover, our approach includes a consistent treatment of systems with switching, such as dc exciters, by deriving and implementing the adjoint jump conditions that arise from state-dependent and time-dependent switchings. The accuracy and the computational efficiency of the proposed approach are demonstrated in comparison with the forward sensitivity analysis approach. This paper focuses primarily on the power system dynamics, but the approach is general and can be applied to hybrid dynamical systems in a broader range of fields.
Autors: Hong Zhang;Shrirang Abhyankar;Emil Constantinescu;Mihai Anitescu;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: May 2017, volume: 64, issue:5, pages: 1247 - 1259
Publisher: IEEE
 
» Discrete-Phase Constant Envelope Precoding for Massive MIMO Systems
Abstract:
We consider downlink of a multiuser massive multiple-input multiple-output (MIMO) system and focus on reducing the hardware costs by using a single common power amplifier and separate phase shifters (PSs) for antenna front-ends. In the previous literature, the use of analog PSs in this setup has been considered. Here, we study the use of practical digital PSs, which only support a limited set of discrete phases. Considering the sum of interference powers as a metric, we formulate the corresponding nonlinear discrete optimization problem and solve for the phases to be used during transmission. We devise a low-complexity algorithm, which employs a trellis structure providing suboptimal, but efficient and effective solutions. We demonstrate via examples that the proposed solutions have comparable performance to conventional analog PS-based algorithms. Furthermore, we prove that by utilizing discrete-phase constant envelope precoding, the interference can be made arbitrarily small by increasing the number of antennas. Therefore, the asymptotic gains promised by massive MIMO systems are preserved. We also obtain closed-form expressions for the rate loss due to errors in the phase and amplitude of the PSs, for both low and high SNR regimes.
Autors: Mohammad Kazemi;Hassan Aghaeinia;Tolga M. Duman;
Appeared in: IEEE Transactions on Communications
Publication date: May 2017, volume: 65, issue:5, pages: 2011 - 2021
Publisher: IEEE
 
» Discriminative Reverse Sparse Tracking via Weighted Multitask Learning
Abstract:
Multitask learning has shown great potentiality for visual tracking under a particle filter framework. However, the recent multitask trackers, which exploit the similarity between all candidates by imposing group sparsity on the candidate representations, have a limitation in robustness due to the diverse sampling of candidates. To deal with this issue, we propose a discriminative reverse sparse tracker via weighted multitask learning. Our positive and negative templates are retained from the target observations and the background, respectively. Here, the templates are reversely represented via the candidates, and the representation of each positive template is viewed as a single task. Compared with existing multitask trackers, the proposed algorithm has the following advantages. First, we regularize the target representations with the -norm to exploit the similarity shared by the positive templates, which is reasonable because of the target appearance consistency in the tracking process. Second, the valuable prior relationship between the candidates and the templates is introduced into the representation model by a weighted multitask learning scheme. Third, both target information and background information are integrated to generate discriminative scores for enhancing the proposed tracker. The experimental results on challenging sequences show that the proposed algorithm is effective and performs favorably against 12 state-of-the-art trackers.
Autors: Yehui Yang;Wenrui Hu;Wensheng Zhang;Tianzhu Zhang;Yuan Xie;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: May 2017, volume: 27, issue:5, pages: 1031 - 1042
Publisher: IEEE
 
» Disseminating the Best Material to Practitioners
Abstract:
As this department celebrates its second year, its editors restate its mission and scope of interest, invite appropriate articles, and look at some previous contributions.
Autors: Phillip Laplante;Steve Counsell;Giuliano Antoniol;
Appeared in: IEEE Software
Publication date: May 2017, volume: 34, issue:3, pages: 111 - 113
Publisher: IEEE
 
» Distributed Algorithms for Computation of Centrality Measures in Complex Networks
Abstract:
This paper is concerned with distributed computation of several commonly used centrality measures in complex networks. In particular, we propose deterministic algorithms, which converge in finite time, for the distributed computation of the degree, closeness and betweenness centrality measures in directed graphs. Regarding eigenvector centrality, we consider the PageRank problem as its typical variant, and design distributed randomized algorithms to compute PageRank for both fixed and time-varying graphs. A key feature of the proposed algorithms is that they do not require to know the network size, which can be simultaneously estimated at every node, and that they are clock-free. To address the PageRank problem of time-varying graphs, we introduce the concept of persistent graph, which eliminates the effect of spamming nodes. Moreover, we prove that these algorithms converge almost surely and in the sense of . Finally, the effectiveness of the proposed algorithms is illustrated via extensive simulations using a classical benchmark.
Autors: Keyou You;Roberto Tempo;Li Qiu;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2017, volume: 62, issue:5, pages: 2080 - 2094
Publisher: IEEE
 
» Distributed Algorithms to Compute Walrasian Equilibrium in Mobile Crowdsensing
Abstract:
In this paper, we consider joint pricing and task allocation in a unified mobile crowdsensing system, where all task initiators and mobile users are viewed as peers. From an exchange market point of view, the pricing and task allocation in such a unified system depend only on the supply and demand since no one can dominate the process, with the optimal solution being characterized by the Walrasian equilibrium. This is quite different from existing approaches, where each task initiator builds a specific mobile crowdsensing system and provides an incentive mechanism to maximize his/her own utility. We design distributed algorithms to compute the Walrasian equilibrium under the scenario where one cloud platform is available in the system. We propose to maximize social welfare of the whole system, and dual decomposition is then employed to divide the social welfare maximization problem into a set of subproblems that can be solved by task initiators and mobile users. We prove that the proposed algorithm converges to the optimal solution of social welfare maximization problem. Further, we show that the prices and task allocation obtained by the algorithm also yields a Walrasian equilibrium. Also, the proposed algorithm does not need the cloud to collect private information such as utility functions of task initiators and cost functions of mobile users. Extensive simulations demonstrate the effectiveness of the proposed algorithms.
Autors: Xiaoming Duan;Chengcheng Zhao;Shibo He;Peng Cheng;Junshan Zhang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 4048 - 4057
Publisher: IEEE
 
» Distributed Continuous-Time Optimization: Nonuniform Gradient Gains, Finite-Time Convergence, and Convex Constraint Set
Abstract:
In this paper, a distributed optimization problem with general differentiable convex objective functions is studied for continuous-time multi-agent systems with single-integrator dynamics. The objective is for multiple agents to cooperatively optimize a team objective function formed by a sum of local objective functions with only local interaction and information while explicitly taking into account nonuniform gradient gains, finite-time convergence, and a common convex constraint set. First, a distributed nonsmooth algorithm is introduced for a special class of convex objective functions that have a quadratic-like form. It is shown that all agents reach a consensus in finite time while minimizing the team objective function asymptotically. Second, a distributed algorithm is presented for general differentiable convex objective functions, in which the interaction gains of each agent can be self-adjusted based on local states. A corresponding condition is then given to guarantee that all agents reach a consensus in finite time while minimizing the team objective function asymptotically. Third, a distributed optimization algorithm with state-dependent gradient gains is given for general differentiable convex objective functions. It is shown that the distributed continuous-time optimization problem can be solved even though the gradient gains are not identical. Fourth, a distributed tracking algorithm combined with a distributed estimation algorithm is given for general differentiable convex objective functions. It is shown that all agents reach a consensus while minimizing the team objective function in finite time. Fifth, as an extension of the previous results, a distributed constrained optimization algorithm with nonuniform gradient gains and a distributed constrained finite-time optimization algorithm are given. It is shown that both algorithms can be used to solve a distributed continuous-time optimization problem with a common convex constraint set. Numerical - xamples are included to illustrate the obtained theoretical results.
Autors: Peng Lin;Wei Ren;Jay A. Farrell;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2017, volume: 62, issue:5, pages: 2239 - 2253
Publisher: IEEE
 
» Distributed Fiber-Optic Acoustic Sensor With Enhanced Response Bandwidth and High Signal-to-Noise Ratio
Abstract:
This paper proposes a novel distributed fiber-optic acoustic sensor, which can solve both the tradeoff between the maximum measurable distance and the spatial resolution, and that between the measurement distance and the vibration response bandwidth. The system is based on frequency-division-multiplexing time-gated digital optical frequency domain reflectometry, which consecutively injects linear-frequency-modulated probe pulses with different frequency ranges. Undersampling method is introduced to reduce the sampling rate of the analog-to-digital converter and the data size, which can reduce the cost of the system and facilitate real-time data processing. In experiments, two simultaneous vibrations with frequency up to 9 kHz are detected over the 24.7-km-long fiber, with a sign-to-noise ratio of 30 dB and spatial resolution of 10 m.
Autors: Dian Chen;Qingwen Liu;Xinyu Fan;Zuyuan He;
Appeared in: Journal of Lightwave Technology
Publication date: May 2017, volume: 35, issue:10, pages: 2037 - 2043
Publisher: IEEE
 
» Distributed Generation Monitoring for Hierarchical Control Applications in Smart Microgrids
Abstract:
Hierarchical control/protection applications in smart microgrids require knowledge of real-time status of distributed generation (DG) systems. Lack or failure of communications with the microgrid central controller (MGCC) can significantly undermine performance of such applications since the MGCC cannot determine the number of operational energy sources. To overcome these challenges, the MGCC needs a secondary mechanism in order to track presence or absence of DG systems. This paper proposes a new monitoring approach that empowers the MGCC to estimate the number of operational DG systems and thus determine the total generation capacity of the microgrid. A parameter estimator is developed to extract an autoregressive model for the synchrophasors of current symmetrical components (CSC) of the main point of common coupling (PCC). The extracted model is used by an adaptive algorithm that identifies abrupt changes in DG by evaluating the norm of forward prediction error. The proposed approach uses real-time synchrophasor data to dynamically update the criterion for event detection and is very robust against abrupt load changes. The performance is verified using extensive simulations of the IEEE 13-Bus benchmark with four photovoltaic (PV) units.
Autors: Younes Seyedi;Houshang Karimi;Santiago Grijalva;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2017, volume: 32, issue:3, pages: 2305 - 2314
Publisher: IEEE
 
» Distributed Learning of Predictive Structures From Multiple Tasks Over Networks
Abstract:
This paper is concerned with the problem of distributed multitask learning over networks, which aims to simultaneously infer multiple node-specific parameter vectors in a collaborative manner. Most of the existing works on the distributed multitask problem modeled the task relatedness by assuming some similarities of parameter vectors in an explicit way. In this paper, we implicitly model the similarity of parameter vectors by assuming that the parameter vectors share a common low-dimensional predictive structure on hypothesis spaces, which is learned using the available data in networks. A distributed structure learning algorithm for the in-network cooperative estimation problem is then derived based on the block coordinate descent method integrated with the inexact alternating direction method of multipliers technique. Simulations on both synthetic and real-world datasets are given to verify the effectiveness of the proposed algorithm. In the case that each node shares a common predictive subspace, it is demonstrated that the proposed multitask algorithm outperforms the noncooperative learning algorithm. Moreover, the use of the inexact approach can significantly reduce the communication bandwidth and still provide the same optimal solution as the corresponding centralized approach.
Autors: Junhao Hua;Chunguang Li;Hui-Liang Shen;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 4246 - 4256
Publisher: IEEE
 
» Distributed LPV State-Feedback Control Under Control Input Saturation
Abstract:
Developed in this note is a scheduled state-feedback controller synthesis method for discrete-time Linear Parameter Varying (LPV) systems subjected to control input saturation constraints. The static state-feedback gain is scheduled with an exact replica of the parameter matrix. The saturation effect is modeled by introducing time-varying parameters as functions of the control inputs, which are also used to schedule the controller. The synthesis method is then specialized to distributed state-feedback by imposing a particular structure on the feedback gain matrix. An explicit formula is also derived for the computation of the distributed control input from a nonlinear equation. The viability of the proposed method is tested in a simulation environment, for a ramp meter traffic flow control problem.
Autors: Azita Dabiri;Balázs Kulcsár;Hakan Köroğlu;
Appeared in: IEEE Transactions on Automatic Control
Publication date: May 2017, volume: 62, issue:5, pages: 2450 - 2456
Publisher: IEEE
 
» Distributed Spectrum Management in TV White Space Networks
Abstract:
We investigate the distributed spectrum management problem in opportunistic TV white space (TVWS) systems using a game theoretical approach that accounts for adjacent-channel interference and spatial reuse. TV band devices (TVBDs) compete to access idle TV channels and select channel “blocks” that optimize an objective function. This function provides a tradeoff between the achieved rate and a cost factor that depends on the interference between TVBDs. We consider practical cases where contiguous or noncontiguous channels can be accessed by TVBDs, imposing realistic constraints on the maximum frequency span between the aggregated/bonded channels. We show that under general conditions, the proposed TVWS management games admit a potential function. Accordingly, a “best response” strategy allows us to determine the spectrum assignment of all players. This algorithm is shown to converge in a few iterations to a Nash equilibrium. Furthermore, we propose an effective algorithm based on Imitation dynamics, where a TVBD probabilistically imitates successful selection strategies of other TVBDs in order to improve its objective function. Numerical results show that our game theoretical framework provides a very effective tradeoff (close to optimal, centralized spectrum allocations) between efficient TV spectrum use and reduction of interference between TVBDs.
Autors: Jocelyne Elias;Fabio Martignon;Lin Chen;Marwan Krunz;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2017, volume: 66, issue:5, pages: 4161 - 4172
Publisher: IEEE
 
» Distributed Teams, Developer Participation, and More
Abstract:
This instalment reports on two talks from the First International Workshop on Collaborative Modeling in MDE (model-driven engineering) and three papers from the 23rd International Conference on Software Analysis, Evolution, and Reengineering. The topics covered include model-driven engineering, forking and developer participation, FLOSS (free/libre and open source software) software projects, and perceptions of release practices.
Autors: Jeffrey C. Carver;Henry Muccini;Aiko Yamashita;
Appeared in: IEEE Software
Publication date: May 2017, volume: 34, issue:3, pages: 114 - 116
Publisher: IEEE
 
» Distributed Containment Maneuvering of Multiple Marine Vessels via Neurodynamics-Based Output Feedback
Abstract:
In this paper, a neurodynamics-based output feedback scheme is proposed for distributed containment maneuvering of marine vessels guided by multiple parameterized paths without using velocity measurements. Each vessel is subject to internal model uncertainties and external disturbances induced by wind, waves, and ocean currents. In order to recover unmeasured velocity information as well as to identify unknown vessel dynamics, an echo state network (ESN) based observer using recorded input–output data is proposed for each vessel. Based on the observed velocity information of neighboring vessels, distributed containment maneuvering laws are developed at the kinematic level. Next, in order to shape the transient motion profile for vessel kinetics to follow, finite-time nonlinear tracking differentiators are employed to generate smooth reference signals as well as to extract the time derivatives of kinematic control laws. Finally, ESN-based dynamic control laws are constructed at the kinetic level. The stability of the closed-loop system is analyzed via input-to-state stability and cascade theory. Simulation results are provided to illustrate the efficacy of the proposed neurodynamics-based output feedback approach.
Autors: Zhouhua Peng;Jun Wang;Dan Wang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 3831 - 3839
Publisher: IEEE
 
» Distribution Systems Operation Considering Energy Storage Devices and Distributed Generation
Abstract:
In this paper, a non-linear programming model to operate distribution systems considering energy storage devices and distributed generation is presented. Mathematical formulation is made taking in to account four terms for minimization: The cost operation of the electrical grid, reducing greenhouse emissions, reduction of electrical losses in conductors and voltage profile improve. As model constraints are employed the active a reactive nodal power balance, maximum capacities from distributed generation and energy storage devices, and the voltage profile regulation. To solve the proposed mathematical model a commercial optimization software GAMS and CONOPT solver are employed. To verify the efficiency and applicability of the model developed are used two test nodes 9 and 10, which have been adapted to the typical operating conditions of Colombian distribution systems. The results show the ability to adapt to various conditions and operating instructions of the utility.
Autors: Oscar Danilo Montoya;Alejandro Grajales;Alejandro Garces;Carlos Alberto Castro;
Appeared in: IEEE Latin America Transactions
Publication date: May 2017, volume: 15, issue:5, pages: 890 - 900
Publisher: IEEE
 
» Disturbance-Adaptive Short-Term Frequency Support of a DFIG Associated With the Variable Gain Based on the ROCOF and Rotor Speed
Abstract:
This paper proposes a disturbance-adaptive short-term frequency support scheme of a doubly fed induction generator (DFIG) that can improve the frequency-supporting capability while ensuring stable operation. In the proposed scheme, the output of the additional control loop is determined as the product of the frequency deviation and adaptive gain, which is modified depending on the rate of change of frequency (ROCOF) and rotor speed. To achieve these objectives, the adaptive gain is set to be high during the early stage of a disturbance, when the ROCOF and rotor speed are high. Until the frequency nadir (FN), the gain decreases with the ROCOF and rotor speed. After the FN, the gain decreases only with the rotor speed. The simulation results demonstrate that the proposed scheme improves the FN and maximum ROCOF while ensuring the stable operation of a DFIG under various wind conditions irrespective of the disturbance conditions by adaptively changing the control gain with the ROCOF and rotor speed, even if the wind speed decreases and a consecutive disturbance occurs.
Autors: Min Hwang;Eduard Muljadi;Gilsoo Jang;Yong Cheol Kang;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2017, volume: 32, issue:3, pages: 1873 - 1881
Publisher: IEEE
 
» Dive into IMS2017 Workshops and Short Courses!
Abstract:
Provides a notice of upcoming conference events of interest to practitioners and researchers.
Autors: Cynthia Hang;Yi-Chi Shih;Kevin Leong;Bryan Wu;Domine Leenaerts;Osama Shanaa;
Appeared in: IEEE Microwave Magazine
Publication date: May 2017, volume: 18, issue:3, pages: 42 - 66
Publisher: IEEE
 
» Diversity Study of a Frequency Selective Surface Transponder for Wearable Applications
Abstract:
This communication presents a semipassive radio frequency identification system in the 2.45-GHz Industrial, Scientific and Medical band. The transponder (or tag) is based on a modulated frequency selective surface (FSS). The FSS is composed of dipoles loaded with varactor diodes that modulate the radar cross section. The FSS transponder is designed to work for wearable and on-body applications and is used for reading and transmitting information from different sensors placed on the body. Experimental results locating the FSS at different positions in real scenarios and also at different places on the body are provided. Multiple FSSs have been used to explore spatial and polarization diversity techniques in order to mitigate the deep fadings that can happen during communication. Noticeable diversity gain has been obtained in both the cases without using antenna diversity in the reader. Finally, this communication describes a proof-of-concept experiment of the communication where two FSSs send digital data using a frequency shift keying modulation.
Autors: J. Lorenzo;A. Lazaro;R. Villarino;D. Girbau;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2701 - 2706
Publisher: IEEE
 
» Diversity Through Adversity [President's Message]
Abstract:
Presents the President's message for this issue of the publication.
Autors: Rabab Ward;
Appeared in: IEEE Signal Processing Magazine
Publication date: May 2017, volume: 34, issue:3, pages: 4 - 5
Publisher: IEEE
 
» Do Not Capture: Automated Obscurity for Pervasive Imaging
Abstract:
The pervasive use of smartphones and wearables can compromise individuals' privacy, as they become unaware subjects of pictures and videos. Do Not Capture is a novel technology that removes unwilling subjects from media at capture time.
Autors: Moo-Ryong Ra;Seungjoon Lee;Emiliano Miluzzo;Eric Zavesky;
Appeared in: IEEE Internet Computing
Publication date: May 2017, volume: 21, issue:3, pages: 82 - 87
Publisher: IEEE
 
» DOA and Gain-Phase Errors Estimation for Noncircular Sources With Central Symmetric Array
Abstract:
The problem of direction-of-arrival (DOA) estimation for noncircular sources impinging on a central symmetric array (CSA) in the presence of sensor gain-phase uncertainties is addressed in this paper. A noniterative method is proposed and the corresponding stochastic Cramér–Rao bound is derived. The proposed method is realized through two steps. First, an eigenstructure-based technique is presented to estimate the spatial signatures. Second, the DOAs are obtained by adopting an element-wise division approach to the estimated spatial signatures, based on which, the sensor gain-phase errors are given in closed-form. The ambiguity of DOA estimation is analyzed as well. The proposed method offers a number of advantages in comparison with the existing methods that apply to CSA. First, the DOA estimator is independent of the sensor phases. Second, the proposed method applies to incoherent sources. Third, the proposed method is capable of providing 360° azimuthal coverage under certain conditions. Fourth, an additional performance gain is achieved by taking the property of noncircular sources into consideration. Numerical simulations are provided to verify the effectiveness of the proposed method.
Autors: Wei Xie;Changsheng Wang;Fei Wen;Jiangbo Liu;Qun Wan;
Appeared in: IEEE Sensors Journal
Publication date: May 2017, volume: 17, issue:10, pages: 3068 - 3078
Publisher: IEEE
 
» Domain Decomposition Approach for Efficient Time-Domain Finite-Element Computation of Winding Losses in Electrical Machines
Abstract:
Finite-element (FE) analysis of winding losses in electrical machines can be computationally uneconomical. Computationally lighter methods often place restrictions on the winding configuration or have been used for time-harmonic problems only. This paper proposes a domain decomposition-type approach for solving this problem. The slots of the machine are modeled by their impulse response functions and coupled together with the rest of the problem. The method places no restrictions on the winding and naturally includes all resistive ac loss components. The method is then evaluated on a 500-kW induction motor. According to the simulations, the method yields precise results 70–100 faster compared with the established FE approach.
Autors: Antti Lehikoinen;Jouni Ikäheimo;Antero Arkkio;Anouar Belahcen;
Appeared in: IEEE Transactions on Magnetics
Publication date: May 2017, volume: 53, issue:5, pages: 1 - 9
Publisher: IEEE
 
» Don't fool Me!: Detection, Characterisation and Diagnosis of Spoofed and Masked Events in Wireless Sensor Networks
Abstract:
Wireless Sensor Networks carry a high risk of being compromised, as their deployments are often unattended, physically accessible and the wireless medium is difficult to secure. Malicious data injections take place when the sensed measurements are maliciously altered to trigger wrong and potentially dangerous responses. When many sensors are compromised, they can collude with each other to alter the measurements making such changes difficult to detect. Distinguishing between genuine and malicious measurements is even more difficult when significant variations may be introduced because of events, especially if more events occur simultaneously. We propose a novel methodology based on wavelet transform to detect malicious data injections, to characterise the responsible sensors, and to distinguish malicious interference from faulty behaviours. The results, both with simulated and real measurements, show that our approach is able to counteract sophisticated attacks, achieving a significant improvement over state-of-the-art approaches.
Autors: Vittorio P. Illiano;Luis Muñoz-González;Emil C. Lupu;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: May 2017, volume: 14, issue:3, pages: 279 - 293
Publisher: IEEE
 
» Downlink and Uplink Decoupling in Two-Tier Heterogeneous Networks With Multi- Antenna Base Stations
Abstract:
In order to improve the uplink performance of future cellular networks, the idea to decouple the downlink (DL) and uplink (UL) association has recently been shown to provide significant gain in terms of both coverage and rate performance. However, all the works are limited to a single input single output (SISO) network. Therefore, to study the gain provided by the DL and UL decoupling in multi-antenna base stations (BSs) setup, we study a two tier heterogeneous network consisting of multi-antenna BSs, and single antenna user equipments (UEs). We use maximal ratio combining (MRC) as a linear receiver at the BSs and tools from stochastic geometry, and we derive tractable expressions for both signal-to-interference ratio (SIR) coverage probability and rate coverage probability. We observe that as the disparity in the beamforming gain of both tiers increases, the gain in terms of SIR coverage probability provided by the decoupled association over non-decoupled association decreases. We further observe that when there is asymmetry in the number of antennas of both tiers, then we need further biasing toward femto-tier on the top of decoupled association to balance the load and get optimal rate coverage probability.
Autors: Mudasar Bacha;Yueping Wu;Bruno Clerckx;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: May 2017, volume: 16, issue:5, pages: 2760 - 2775
Publisher: IEEE
 
» Downlink Transmission of Short Packets: Framing and Control Information Revisited
Abstract:
Cellular wireless systems rely on frame-based transmissions. The frame design is conventionally based on heuristics, consisting of a frame header and a data part. The frame header contains control information that provides pointers to the messages within the data part. In this paper, we revisit the principles of frame design and show the impact of the new design in scenarios that feature short data packets, which are central to various 5G and Internet of Things applications. We treat framing for downlink transmission in an AWGN broadcast channel with users, where the sizes of the messages to the users are random variables. Using approximations from finite blocklength information theory, we establish a framework in which a message to a given user is not necessarily encoded as a single packet, but may be grouped with messages to other users and benefit from the improved efficiency of longer codes. This requires changes in the way control information is sent, and it requires that the users need to spend power decoding other messages, thereby increasing the average power consumption. We show that the common heuristic design is only one point on a curve that represents the tradeoff between latency and power consumption.
Autors: Kasper Fløe Trillingsgaard;Petar Popovski;
Appeared in: IEEE Transactions on Communications
Publication date: May 2017, volume: 65, issue:5, pages: 2048 - 2061
Publisher: IEEE
 
» Dr. Taylor's X-Ray machine [Past Forward]
Abstract:
When it was completed in 1940, the 1.4-million-volt X-ray generator at the U.S. National Bureau of Standards was the most powerful in the world. In this photo from 1959, Lauriston S. Taylor, chief of the agency’s X-ray section, stands in front of a chalkboard showing tissue doses that have been carefully calculated to either keep humans safe or give them superpowers.
Autors: Evan Ackerman;
Appeared in: IEEE Spectrum
Publication date: May 2017, volume: 54, issue:5, pages: 56 - 56
Publisher: IEEE
 
» Drivable Road Reconstruction for Intelligent Vehicles Based on Two-View Geometry
Abstract:
This paper presents a road reconstruction algorithm based on two-view geometry. A general geometric model for both planar and nonplanar scenes is proposed with respect to a reference plane. Then, points in the scene can be described geometrically by the projective parallax with respect to the reference plane. In practice, the grounding plane of the vehicle is selected as the reference plane. A row-wise image registration method is proposed to estimate the parallax information effectively. Based on the geometric model, points in the scene can be reconstructed as relative position and height information with respect to the reference plane. For road detection, the scene can be segmented where the height changes abruptly. Then, the road region is obtained by a diffusion strategy. The road surface can be reconstructed using the proposed model. Experiments are conducted to show the effectiveness and robustness of the proposed approach. The proposed approach is general in the sense that it does not rely on the priors of road appearance and structure, and it is not restricted to specific stereo camera configurations making it extendable to other multicamera systems.
Autors: Bingxi Jia;Jian Chen;Kaixiang Zhang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 3696 - 3706
Publisher: IEEE
 
» Driver-Automation Cooperative Approach for Shared Steering Control Under Multiple System Constraints: Design and Experiments
Abstract:
This paper addresses the shared lateral control between a human driver and a lane keeping assist system of intelligent vehicles for both lane keeping and obstacle avoidance. This control issue is very challenging in today's automotive industry due to the human–machine interaction involved in the control design. In this paper, we propose a new approach to consider such an interaction via a fictive driver activity parameter introduced into the road–vehicle system. Hence, the steering assistance actions can be computed according to the driver's real-time behaviors. The Takagi–Sugeno fuzzy control approach is proposed to deal with the time-varying driver activity parameter and vehicle speed. Especially, the concept of robust invariant set is exploited using Lyapunov arguments to handle theoretically both system state and control input limitations. Considering these system constraints in the control design procedure aims to improve the driver's safety and comfort. Experimental tests with a human driver and an advanced interactive dynamic driving simulator are conducted to show the effectiveness of the proposed method.
Autors: Anh-Tu Nguyen;Chouki Sentouh;Jean-Christophe Popieul;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 3819 - 3830
Publisher: IEEE
 
» Dual Band Metamaterial Cherenkov Oscillator With a Waveguide Coupler
Abstract:
We propose a waveguide coupler based on a metamaterial slow-wave structure (SWS) and then present a dual band metamaterial Cherenkov oscillator. The high-frequency characteristics of the SWS are studied by High Frequency Structure Simulator, indicating that both space harmonic of fundamental mode and space harmonic of first higher order mode exhibit “backward” wave properties and high interaction impedances. Meanwhile, the transmission property of the metamaterial SWS with the waveguide couplers is investigated. The simulation results show two passbands, which are verified by the experiment. In addition, we use linear theory to predict the starting currents, which are verified by Computer Simulation Technology (CST) Particle-In-Cell (PIC) simulation. Furthermore, the performance of the dual band metamaterial Cherenkov oscillator is studied using the CST PIC solver. The results show that the electronic efficiency of the proposed oscillator reaches 52% and its tuning bandwidths are ~7 and ~30 MHz for Modes 1 and 2, respectively. The CST PIC simulation results agree well with those using the Computer-aided highly efficient electromagnetic particle-in-cell code. These results indicate that the proposed oscillator has small size, dual band property, and high electronic efficiency.
Autors: Xianfeng Tang;Zhaoyun Duan;Xinwu Ma;Shifeng Li;Fei Wang;Yuanyuan Wang;Yubin Gong;Jinjun Feng;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2017, volume: 64, issue:5, pages: 2376 - 2382
Publisher: IEEE
 
» Dual-Mode Branch-Line/Rat-Race Coupler Using Composite Right-/Left-Handed Lines
Abstract:
A novel dual-operational mode directional coupler, functioning as a branch-line coupler at one frequency but identically to a rat-race coupler in the other one, is proposed and investigated. To fulfill the unusual design, the characteristic impedance and phase response of a conventional composite right-/left-handed line are controlled simultaneously at both operating frequencies. Analytical design equations are derived and verified by experimental results. The dual-mode coupler shows typical responses of a 90° and 180° coupler, respectively, in the first and second (1.5/2.5 GHz) operating bands. The fractional bandwidths are 8% and 16%.
Autors: Li Chang;Tzyh-Ghuang Ma;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: May 2017, volume: 27, issue:5, pages: 449 - 451
Publisher: IEEE
 
» Dual-Parameters Optical Fiber Sensor With Enhanced Resolution Using Twisted MMF Based on SMS Structure
Abstract:
A compact and low cost optical fiber sensor by introducing higher order modes interference with fiber twisting based on single-mode-multimode-single-mode structure is proposed and demonstrated for simultaneous measurement of strain and temperature. The sensor is fabricated by heating and twisting a section of multimode fiber (MMF), which is spliced between two single-mode fibers. By adjusting the heating temperature and rotate speed during fabrication, the twisted region is introduced in MMF, which is able to couple more power of light into the cladding and introduce higher order modes in modal interferences. With this method, strain sensitivity of −7 and −2.19 pm/ as well as temperature sensitivity of 17.33 and 13 pm/°C are obtained. By spatial frequency demodulation method, measurement resolution reaches and ±0.89 °C, which has great potential in dual-parameters measurement of temperature and strain with high resolution.
Autors: Yuan Sun;Deming Liu;Ping Lu;Qizhen Sun;Wei Yang;Shun Wang;Li Liu;Jiangshan Zhang;
Appeared in: IEEE Sensors Journal
Publication date: May 2017, volume: 17, issue:10, pages: 3045 - 3051
Publisher: IEEE
 
» Dynamic Analysis of a Novel Moving Magnet Linear Actuator
Abstract:
A novel moving magnet linear actuator is proposed for linear oscillations in the linear resonant compressors for household refrigerators. This paper provides stator and armature design including CAD model and geometric parameters. Furthermore, the working principle of the proposed actuator is explained. The stator assembly is composed of two reversely wound coils, which are electrically excited with single phase ac power and oscillates the radially magnetized armature. With the help of the electromechanical analytical model, the dynamic parameters such as stroke, velocity, and acceleration of the armature are derived. Additionally, the time-dependent current model of the stator winding is proposed. An experimental setup is used to validate these responses at the resonance excitation frequency with the help of sensors. The system kinetics are discussed to estimate the spring, damping, inertial, and magnetic forces. A simulation is executed to estimate the time-domain responses of these dynamic parameters and the effects of excitation frequency are discussed. The force models are experimentally validated at the resonance frequency excitation. In order to evaluate the performance of the proposed actuator, a comparison of the performance parameters, such as efficiency, stroke, current, and mass flow rate is demonstrated with the conventional rotary as well as the linear motors for linear compressor application.
Autors: Adnan Hassan;Armin Bijanzad;Ismail Lazoglu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 3758 - 3766
Publisher: IEEE
 
» Dynamic Appliances Scheduling in Collaborative MicroGrids System
Abstract:
In this paper, a new approach that is based on a collaborative system of MicroGrids (MGs) is proposed to enable household appliance scheduling. To achieve this, appliances are categorized into flexible and non-flexible deferrable loads (DLs), according to their electrical components. We propose a dynamic scheduling algorithm where users can systematically manage the operation of their electric appliances. The main challenge is to develop a flattening function calculus (reshaping) for both flexible and non-flexible DLs. In addition, implementation of the proposed algorithm would require dynamically analyzing two successive multiobjective optimization (MOO) problems. The first one targets the activation schedule of non-flexible DLs and the second one deals with the power profiles of flexible DLs. The MOO problems are resolved by using a fast and elitist multiobjective genetic algorithm (NSGA-II). Finally, in order to show the efficiency of the proposed approach, a case study of a collaborative system that consists of 40 MGs registered in the load curve for the flattening program has been developed. The results verify that the load curve can indeed become very flat by applying the proposed scheduling approach.
Autors: Hasnae Bilil;Ghassane Aniba;Hamid Gharavi;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2017, volume: 32, issue:3, pages: 2276 - 2287
Publisher: IEEE
 
» Dynamic Binary Translation of VLIW Codes on Scalar Architectures
Abstract:
Many of the recently announced integrated manycore architectures targeting specific applications embed several, if not many, very long instruction word (VLIW) processors. To start developing software while the hardware is still being designed, virtual prototypes of the full system are commonly used. Fast processor simulation is thus a requirement. To that aim, this paper introduces a strategy to perform dynamic binary translation (DBT) of VLIW codes on scalar architectures. We propose a high level simulation algorithm which takes into account VLIW oddities, such as explicit instruction parallelism, instructions with non unit register update latency, and delayed slots in branches. We present the implementation details of this algorithm within a DBT environment, as it raises many corner cases that are irrelevant in scalar DBT. Our experiments confirm that our solution is functionally correct, and show speedups of 1 and 2 orders of magnitude compared to raw instruction interpretation, even though no optimizations were performed on the code during and after translation.
Autors: Luc Michel;Frédéric Pétrot;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: May 2017, volume: 36, issue:5, pages: 789 - 800
Publisher: IEEE
 
» Dynamic Characterization of the Incidence Angle Dependence of Backscatter Using Metop ASCAT
Abstract:
Observing a target from different look and incidence angles is one of the key features of the Advanced Scatterometer (ASCAT) on-board the series of Metop satellites. The incidence angle dependency of backscatter plays an important role in extracting useful information for the retrieval of geophysical parameters. The TU Wien change detection algorithm exploits the multiangle measurement capabilities of ASCAT to retrieve relative surface soil moisture content. In the TU Wien algorithm, the incidence angle dependence of backscatter is characterized with a second-order polynomial and its coefficients are estimated from several years of data due to robustness. Recently, however, it has been shown by Melzer [1], that a kernel smoother (KS) holds promise to characterize the polynomial coefficients on an interannual basis. In this study, we tested the performance and robustness of the KS globally, by comparing the results obtained from ASCAT on-board Metop-A and Metop-B independently. Overall, a good agreement has been found between Metop-A and Metop-B confirming a robust interannual estimation of the incidence angle dependence of backscatter using the KS. However, in two cases, the prevailing conditions on the ground complicated the estimation: areas with very low signal variation and sandy deserts. An analysis of Hovmöller diagrams provided insight into seasonal variations, also revealing small remaining biases between the instruments. The dynamic characterization of the incidence angle dependence of backscatter allows to study the temporal evolution in more detail and, at the same time, moving a step further on the vegetation correction in the TU Wien soil moisture algorithm.
Autors: Sebastian Hahn;Christoph Reimer;Mariette Vreugdenhil;Thomas Melzer;Wolfgang Wagner;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: May 2017, volume: 10, issue:5, pages: 2348 - 2359
Publisher: IEEE
 
» Dynamic Facet Ordering for Faceted Product Search Engines
Abstract:
Faceted browsing is widely used in Web shops and product comparison sites. In these cases, a fixed ordered list of facets is often employed. This approach suffers from two main issues. First, one needs to invest a significant amount of time to devise an effective list. Second, with a fixed list of facets, it can happen that a facet becomes useless if all products that match the query are associated to that particular facet. In this work, we present a framework for dynamic facet ordering in e-commerce. Based on measures for specificity and dispersion of facet values, the fully automated algorithm ranks those properties and facets on top that lead to a quick drill-down for any possible target product. In contrast to existing solutions, the framework addresses e-commerce specific aspects, such as the possibility of multiple clicks, the grouping of facets by their corresponding properties, and the abundance of numeric facets. In a large-scale simulation and user study, our approach was, in general, favorably compared to a facet list created by domain experts, a greedy approach as baseline, and a state-of-the-art entropy-based solution.
Autors: Damir Vandic;Steven Aanen;Flavius Frasincar;Uzay Kaymak;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: May 2017, volume: 29, issue:5, pages: 1004 - 1016
Publisher: IEEE
 
» Dynamic Fuzzy Cognitive Maps Applied in Realibility Centered Maintanance of Electric Motors
Abstract:
The industry has systems and machines that need to operate within appropriate parameters to ensure quality in production. In this context it is necessary to maintain, through maintenance, the conditions necessary for proper operation. Thus, through the Reliability Centered Maintenance with quantitative feedback by Fuzzy Cognitive Maps applied to electric motors, can suggest a better reliability, proposal of this research. This paper discusses the Reliability Centered Maintenance (RCM) with reference to a generic Check list of electric motors' maintenance. Through the maintenance actions for correction of faults and/or defects, it can be modeled a critical and qualitative FCM that will present a quantitative diagnosis aimed at a proposal for a computational tool to assist in the maintenance management, adding improvements to the system
Autors: Marcio Mendonca;Ivan Rossato Chun;Michelle Eliza Casagrande Rocha;
Appeared in: IEEE Latin America Transactions
Publication date: May 2017, volume: 15, issue:5, pages: 827 - 834
Publisher: IEEE
 
» Dynamic Strain Measurement Using Small Gain Stimulated Brillouin Scattering in STFT-BOTDR
Abstract:
A distributed dynamic strain measurement is demonstrated using small gain stimulated Brillouin scattering (SBS) in Brillouin optical time domain reflectometry based on the short-time Fourier transform algorithm. The input power limits, frequency uncertainties for given pulse durations, fiber lengths, and the number of averaging are calculated. The output signal power and the signal-to-noise ratio of the system output are enhanced by SBS. It is found that the signal processing is faster and requires fewer averaging to achieve dynamic sensing performance along the fiber under test. A 60-Hz vibration on a 6-m fiber section at the end of a 935-m fiber is detected with the spatial resolution of 4 m with a sampling rate of 2.5 kS/s.
Autors: Bo Li;Linqing Luo;Yifei Yu;Kenichi Soga;Jize Yan;
Appeared in: IEEE Sensors Journal
Publication date: May 2017, volume: 17, issue:9, pages: 2718 - 2724
Publisher: IEEE
 
» Dynamic Subarrays for Hybrid Precoding in Wideband mmWave MIMO Systems
Abstract:
Hybrid analog/digital precoding architectures can address the tradeoff between achievable spectral efficiency and power consumption in large-scale MIMO systems. This makes them a promising candidate for millimeter wave systems, which deploy large antenna arrays at both the transmitter and the receiver to guarantee sufficient received signal power. Most prior work on hybrid precoding focused on narrowband channels and assumed fully connected hybrid architectures. Millimeter wave (mmWave) systems, though, are expected to be wideband with frequency selectivity. In this paper, a closed-form solution for fully connected OFDM-based hybrid analog/digital precoding is developed for frequency selective mmWave systems. This solution is then extended to partially connected but fixed architectures in which each RF chain is connected to a specific subset of the antennas. The derived solutions give insights into how the hybrid subarray structures should be designed. Based on this, a novel technique that dynamically constructs the hybrid subarrays knowing the long-term channel characteristics is developed. Simulation results show that the proposed hybrid precoding solutions achieve spectral efficiencies close to that obtained with fully digital architectures in wideband mmWave channels. Furthermore, the results indicate that the developed dynamic subarray solution outperforms the fixed hybrid subarray structures in various system and channel conditions.
Autors: Sungwoo Park;Ahmed Alkhateeb;Robert W. Heath;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: May 2017, volume: 16, issue:5, pages: 2907 - 2920
Publisher: IEEE
 
» Dynamic Variable Time-Stepping Schemes for Real-Time FPGA-Based Nonlinear Electromagnetic Transient Emulation
Abstract:
Electromagnetic transient (EMT) simulation of nonlinear elements in power systems is a particular challenge due to the requirements of an accurate representation and an efficient solution. The existing real-time simulators utilize a piecewise linear representation along with a fixed time step for the solution of nonlinear elements. This paper proposes the detailed methodologies for applying variable time stepping to real-time EMT simulation to improve the simulation accuracy and efficiency. The challenges, the feasible solutions, and corresponding restrictions of applying various variable time-stepping schemes along with nonlinear element solution methods in real time are discussed. The offline simulation and the real-time hardware emulation of two case studies, a full-bridge diode circuit and a power transmission system, are presented. The case studies were implemented on the field-programmable gate array device (Xilinx Virtex-7 XC7VX485T) in real time using high-level synthesis tool to achieve a parallelized and pipelined hardware design with minimum coding effort. The real-time emulation results captured by an oscilloscope are validated against the offline simulation on Saber and PSCAD/EMTDC software tools.
Autors: Zhuoxuan Shen;Venkata Dinavahi;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: May 2017, volume: 64, issue:5, pages: 4006 - 4016
Publisher: IEEE
 
» Dynamic Whitening Saliency
Abstract:
General dynamic scenes involve multiple rigid and flexible objects, with relative and common motion, camera induced or not. The complexity of the motion events together with their strong spatio-temporal correlations make the estimation of dynamic visual saliency a big computational challenge. In this work, we propose a computational model of saliency based on the assumption that perceptual relevant information is carried by high-order statistical structures. Through whitening, we completely remove the second-order information (correlations and variances) of the data, gaining access to the relevant information. The proposed approach is an analytically tractable and computationally simple framework which we call Dynamic Adaptive Whitening Saliency (AWS-D). For model assessment, the provided saliency maps were used to predict the fixations of human observers over six public video datasets, and also to reproduce the human behavior under certain psychophysical experiments (dynamic pop-out). The results demonstrate that AWS-D beats state-of-the-art dynamic saliency models, and suggest that the model might contain the basis to understand the key mechanisms of visual saliency. Experimental evaluation was performed using an extension to video of the well-known methodology for static images, together with a bootstrap permutation test (random label hypothesis) which yields additional information about temporal evolution of the metrics statistical significance.
Autors: Víctor Leborán;Antón García-Díaz;Xosé R. Fdez-Vidal;Xosé M. Pardo;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: May 2017, volume: 39, issue:5, pages: 893 - 907
Publisher: IEEE
 
» E Komo Mai from the IMS2017 General Chair
Abstract:
Provides a notice of upcoming conference events of interest to practitioners and researchers.
Autors: Wayne Shiroma;
Appeared in: IEEE Microwave Magazine
Publication date: May 2017, volume: 18, issue:3, pages: 16 - 22
Publisher: IEEE
 
» Earphone showdown, part 2 - The DQSM D2, LKER I8, and Crazy Cello [Resources_Review]
Abstract:
More than a year ago I noticed I was spending most of my music-listening time playing songs on my smartphone. That realization sent me on a quest to find the most inexpensive earphone-based setup that would give me high-end, audiophile sound. I listened to dozens of earphones, half a dozen headphone amplifiers, and a like number of digital-to-analog converter-headphone amplifiers (DAC-headphone amplifiers). I found a few gems, such as the DragonFly Red DAC-headphone amplifier from Audioquest, in Irvine, Calif.
Autors: Glenn Zorpette;
Appeared in: IEEE Spectrum
Publication date: May 2017, volume: 54, issue:5, pages: 23 - 23
Publisher: IEEE
 
» Economic Dispatch Under Uncertainty: The Probabilistic Envelopes Approach
Abstract:
With fast-paced renewable energy integration, stochastic methods are emerging as a viable alternative to traditional power system operations planning under uncertainty. The value of stochastic planning lies in its effectiveness at reducing operational costs while allowing higher penetration levels of renewable sources, and without much sacrifice to system security. This is under the premise that the decision maker may not need to fully hedge against more extreme and costlier events that exhibit lower probabilities of occurrence. On the other hand, stochastic methods do suffer from the curse of dimensionality, which renders them computationally intractable for practical application. Here, we propose a novel hybrid robust-stochastic approach based on the flexibility envelopes concept. It circumvents the curse of dimensionality by using probability weighted envelopes to enclose the evolution of the net load uncertainty over the planning horizon. The new approach is illustrated by a receding-horizon economic dispatch example, to compare its effectiveness to robust planning and stochastic planning with a scenario tree.
Autors: Hussam Nosair;François Bouffard;
Appeared in: IEEE Transactions on Power Systems
Publication date: May 2017, volume: 32, issue:3, pages: 1701 - 1710
Publisher: IEEE
 
» Edge Popularity Prediction Based on Social-Driven Propagation Dynamics
Abstract:
Caching contents in edge networks can reduce latency and lighten the burden on backhaul links. Since the capacity of cache nodes is limited, accurate content popularity distribution is crucial to the effectual usage of cache capacity. However, existing popularity prediction models stem from big data and, hence, may suffer poor accuracy due to the small population in edge caching. In this letter, we propose a social-driven propagation dynamics-based prediction model, which requires neither training phases nor prior knowledge. Specifically, we first explore social relationships to bridge the gap between small population and prediction accuracy under susceptible-infected-recovery model. Then, a discrete-time markov chain approach is proposed to predict the viewing probability of certain contents from the perspective of individuals. Simulations validate that our proposed model outperforms other solutions significantly, by improving up to 94% in accuracy and 99% less runtime overhead.
Autors: Shuo He;Hui Tian;Xinchen Lyu;
Appeared in: IEEE Communications Letters
Publication date: May 2017, volume: 21, issue:5, pages: 1027 - 1030
Publisher: IEEE
 
» Edge Position Detection of On-line Charged Vehicles With Segmental Wireless Power Supply
Abstract:
Online charged electrical vehicles (EVs) with segmental wireless power supply obtain energy from power tracks without a physical cable contact while traveling. When a vehicle moves from one segmental track to another, the power supply coils should switch accordingly to provide energy continually at various positions. As the secondary coil fixed in the vehicle moves along the primary coil mounted in the segmental track, the mutual inductance of these two coils changes accordingly, which results in the varying of the phase angle that the current lags the voltage in the resonant circuit at the primary side. The paper presents a method to decide the power switching time through detecting the changing of the phase angle. A higher phase angle varying range (PAVR) is preferred to achieve a better position judgment. Quality factors at the primary and secondary sides, as well as the mutual inductance between two sides for the higher PAVR, are analyzed. The phase angle change can be detected in the circuit at the primary side when an EV leaves the energized coil region. Besides that, a detecting signal is introduced to find the approaching of EVs for those de-energized coils. The system robustness and magnetic saturation are also analyzed. A scaled-down laboratory prototype is set up to test the proposed method. Within parameter drifts of ±4% of the rating inductance or capacitance, the prototype works perfectly under the rated operation frequency and switching threshold angle. Experiments show that the position detection method can detect not only the approaching but the leaving of vehicles as well.
Autors: Qijun Deng;Jiangtao Liu;Dariusz Czarkowski;Mariusz Bojarski;Jing Chen;Wenshan Hu;Hong Zhou;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: May 2017, volume: 66, issue:5, pages: 3610 - 3621
Publisher: IEEE
 
» Editor's Note
Abstract:
Autors: Nei Kato;
Appeared in: IEEE Network
Publication date: May 2017, volume: 31, issue:3, pages: 2 - 2
Publisher: IEEE
 
» Editorial
Abstract:
Presents an editorial on the importance of supporting and mentoring female engineers.
Autors: Hulya Kirkici;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: May 2017, volume: 33, issue:3, pages: 4 - 5
Publisher: IEEE
 
» Editorial for May 2017 Issue
Abstract:
Pressents the introductory editorial for this issue of the publication.
Autors: RAJIV SABHERWAL;
Appeared in: IEEE Transactions on Engineering Management
Publication date: May 2017, volume: 64, issue:2, pages: 117 - 119
Publisher: IEEE
 
» Editorial Inaugural Issue of the “Journal-Within-a-Journal” on Microwave Systems and Applications
Abstract:
The globalization of the microwave and RF application space and commercial market has led to a situation in which no microwave engineer can remain solely focused on component design. Modern engineers now use complex CAD tools that allow them to reach deep into many aspects of system design as well, and refine their designs to improve overall system performance. Although radio communications were at the origin of RF technologies in the late nineteenth century and the first two decades of the twentieth century, the system-level design has embraced many more applications of RF and microwave technologies, such as radar, sensing, heating, and imaging.
Autors: José Carlos Pedro;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: May 2017, volume: 65, issue:5, pages: 1649 - 1649
Publisher: IEEE
 
» Editorial to the regular issue
Abstract:
This is the 5st issue of the IEEE Latin America Transactions of the year 2017. Volume 15 Issue 5, Mayl 2017
Autors: Mirela Sechi Moretti Annoni Notare;
Appeared in: IEEE Latin America Transactions
Publication date: May 2017, volume: 15, issue:5, pages: 769 - 778
Publisher: IEEE
 
» Editorial: A Message from the Incoming Editor-in-Chief
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Marwan Krunz;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: May 2017, volume: 16, issue:5, pages: 1199 - 1202
Publisher: IEEE
 
» EEG-Informed Attended Speaker Extraction From Recorded Speech Mixtures With Application in Neuro-Steered Hearing Prostheses
Abstract:
Objective: We aim to extract and denoise the attended speaker in a noisy two-speaker acoustic scenario, relying on microphone array recordings from a binaural hearing aid, which are complemented with electroencephalography (EEG) recordings to infer the speaker of interest. Methods: In this study, we propose a modular processing flow that first extracts the two speech envelopes from the microphone recordings, then selects the attended speech envelope based on the EEG, and finally uses this envelope to inform a multichannel speech separation and denoising algorithm. Results: Strong suppression of interfering (unattended) speech and background noise is achieved, while the attended speech is preserved. Furthermore, EEG-based auditory attention detection (AAD) is shown to be robust to the use of noisy speech signals. Conclusions: Our results show that AAD-based speaker extraction from microphone array recordings is feasible and robust, even in noisy acoustic environments, and without access to the clean speech signals to perform EEG-based AAD. Significance: Current research on AAD always assumes the availability of the clean speech signals, which limits the applicability in real settings. We have extended this research to detect the attended speaker even when only microphone recordings with noisy speech mixtures are available. This is an enabling ingredient for new brain–computer interfaces and effective filtering schemes in neuro-steered hearing prostheses. Here, we provide a first proof of concept for EEG-informed attended speaker extraction and denoising.
Autors: Simon Van Eyndhoven;Tom Francart;Alexander Bertrand;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: May 2017, volume: 64, issue:5, pages: 1045 - 1056
Publisher: IEEE
 
» Effect of External Magnetic Field Loaded at the Initial Period of Inertial Stretching Stage on the Stability of Shaped Charge Jet
Abstract:
In this paper, the effect of external magnetic field loaded at the initial period of inertial stretching stage on a jet produced by Ø56-mm shaped charge is evaluated through the depth-of-penetration (DOP) test method. Experimental results are compared with the results obtained under the field loaded at the later inertial stretching stage. A standoff of 650 mm is used in the experiments, in which the shaped charge jet can undergo formation, elongation, breakup, rotation, and drift. The initial energy is provided by a capacitor bank, which is loaded on the solenoid to generate a magnetic field used for coupling with the jet. The external magnetic field loaded at the initial period of inertial stretching stage can enhance the stability of the jet and increase its DOP. The penetration capability of the jet in the above-mentioned condition is increased by 77.4%.
Autors: Bin Ma;Zhengxiang Huang;Qiangqiang Xiao;Xudong Zu;Xin Jia;Long Ji;
Appeared in: IEEE Transactions on Plasma Science
Publication date: May 2017, volume: 45, issue:5, pages: 875 - 881
Publisher: IEEE
 
» Effect of In and Zn Content on Structural and Electrical Properties of InZnSnO Thin-Film Transistors Using an Yb2TiO5 Gate Dielectric
Abstract:
In this paper, we investigated the effect of In and Zn content on the structural properties and electrical characteristics of amorphous indium–zinc–tin oxide (-InZnSnO) thin-film transistors (TFTs) featuring an Yb2TiO5 gate dielectric. The Yb2TiO5 -InZnSnO TFT prepared at the 30-W condition exhibited better electrical characteristics in terms of a low threshold voltage of 0.52 V, a high ratio of , a low subthreshold swing of 203 mV/decade, and a large field-effect mobility of 27.9 cm2/Vs. We attribute these results to the optimal Zn and Sn content on InZnSnO channel forming a smooth surface and thus reducing density of interface states at the oxide/channel interface.
Autors: Tung-Ming Pan;Bo-Jung Peng;Jim-Long Her;Bih-Show Lou;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2017, volume: 64, issue:5, pages: 2233 - 2238
Publisher: IEEE
 
» Effect of Mechanical Strain on Hydrogenated Amorphous Silicon Thin-Film Transistors and Compensation Circuits on Flexible Substrates
Abstract:
Hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) compensation pixel circuits were fabricated on polyethylene naphthalate substrates at amax-imumtemperature of 170 °C. The typical a-Si:H TFTs showed a field-effect mobility () of 0.8–1.1 cm/Vs, a threshold voltage () of 2–3.3 V, a subthreshold swing (SS) of ~0.65 V/decade, and an ON/OFF current ratio of –. Under DC gate-bias stress without compensation, the TFT drive current decreased by ~50% withoutmechanical strain and ~60% with applied tensile strain. The TFT circuits effectively compensated for the change in the TFT drive current to within 10% of the original drive current value under mechanically strained and unstrained states. The orientation of the TFT within the circuit was found to affect the circuit compensation; TFTs having a channel length perpendicular to the mechanical strain were found to have a 50% higher threshold voltage shift () compared to devices parallel to the applied strain.
Autors: Czang-Ho Lee;Nikolas P. Papadopoulos;Manoj Sachdev;William S. Wong;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2017, volume: 64, issue:5, pages: 2016 - 2021
Publisher: IEEE
 
» Effect of Quality Factor on Determining the Optimal Position of a Transmitter in Wireless Power Transfer Using a Relay
Abstract:
In this letter, the optimal placement of a transmitter is investigated under a given arrangement of a relay and a receiver for nonradiative wireless power transfer. Specifically, a closed-form equation is derived for the optimal coupling coefficient between the transmitter and the relay using an equivalent circuit model. Based on this theoretical analysis, it is found that the quality factor of the transmitter has a great effect on determining its optimal placement. In particular, the transmission efficiency can be improved by locating the resonator with a smaller quality factor (e.g., transmitter or receiver) closer to the relay. In order to support the validity of the analysis, the resonators, including the relay, receiver, and three different types of transmitters, are experimentally designed and fabricated. It is shown that our analytical results are well matched with the measured ones in various settings.
Autors: Kisong Lee;Sung Ho Chae;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: May 2017, volume: 27, issue:5, pages: 521 - 523
Publisher: IEEE
 
» Effective Nonlinear Surface Impedance of Conductive Magnetic Slabs
Abstract:
A new formula is developed for the surface impedance of a nonlinear magnetic conductive semi-infinite slab. The impedance expression allows for proper incorporation of the nonlinear characteristic of the magnetic material, also using an analytical expression. Thus, the usual step representation of the – curve is superseded. Normal and tangential magnetic components may simultaneously exist, avoiding the classical premise that only the tangential component exists. This way, it is possible to represent highly magnetic permeable materials where the normal component of the magnetic field is the main one. Our analytical formulation and solution can be for example used for calculation of losses in electrical machines or along with FE software code to avoid meshing of magnetic conductive regions.
Autors: Rafael Escarela-Perez;Serguei Maximov;Juan Carlos Olivares-Galvan;Enrique Melgoza;M. A. Arjona;
Appeared in: IEEE Transactions on Magnetics
Publication date: May 2017, volume: 53, issue:5, pages: 1 - 12
Publisher: IEEE
 
» Effective Richardson Constant of Sol-Gel Derived TiO2 Films in n-TiO2/p-Si Heterojunctions
Abstract:
The effective Richardson constant of sol–gel derived TiO2 thin film has been estimated possibly for the first time from temperature-dependent current–voltage (––) characteristics of p-Si/n-TiO2 thin-film heterojunction diode by including the barrier height inhomogeneity at p-Si/n-TiO2 interface. The thermionic emission theory-based –– characteristics have been modified by assuming a Gaussian distributed barrier height at the heterojunction interface. The Richardson plot shows a nearly ideal Richardson constant of ~1265.57 Acm−2K−2, which is not only very close to its theoretical value of ~1200 Acm−2K−2 for n-TiO2 (with ), but also the first result reported.
Autors: Gopal Rawat;Hemant Kumar;Yogesh Kumar;Chandan Kumar;Divya Somvanshi;Satyabrata Jit;
Appeared in: IEEE Electron Device Letters
Publication date: May 2017, volume: 38, issue:5, pages: 633 - 636
Publisher: IEEE
 
» Effective Self Adaptive Multiple Source Localization Technique by Primal Dual Interior Point Method in Binary Sensor Networks
Abstract:
Wireless sensor networks are creating a new era of pervasive computing applications, such as various monitoring and tracking system. The sensor network consists of so many tiny sensor nodes that have so many critical challenges, since they are battery operated and have limited processing capabilities. Binary sensor networks are modeled in a way that the sensor nodes can communicate with the only 1 b of information. One of the challenges in a binary sensor network is to localize the multiple sources. Very few works have been done considering this challenge. Localization failure may cause the whole system useless. We propose a multiple source localization method. We convert the localization problem into an optimization problem, and we solve that optimization problem using primal dual interior point method. Simulation results show that our proposed method provides better performance in every perspective compared with the existing works.
Autors: Muhidul Islam Khan;Kewen Xia;
Appeared in: IEEE Communications Letters
Publication date: May 2017, volume: 21, issue:5, pages: 1119 - 1122
Publisher: IEEE
 
» Effectively Interpreting Discrete Wavelet Transformed Signals [Lecture Notes]
Abstract:
Following two decades of research focusing on the discrete wavelet transform (DWT) and driven by students' high level of questioning, I decided to write this essay on one of the most significant tools for time-frequency signal analysis. As it is widely applicable in a variety of fields, I invite readers to follow this lecture note, which is specially dedicated to show a practical strategy for the interpretation of DWT-based transformed signals while extracting useful information from them. The particular focus resides on the procedure used to find the time support of frequencies and how it is influenced by the wavelet family and the support size of corresponding filters.
Autors: Rodrigo Capobianco Guido;
Appeared in: IEEE Signal Processing Magazine
Publication date: May 2017, volume: 34, issue:3, pages: 89 - 100
Publisher: IEEE
 
» Effects of Channel Layer Thickness on Characteristics of Flexible Nickel-Doped Zinc Oxide Thin-Film Transistors
Abstract:
We have fabricated fully transparent high performance flexible nickel-doped zinc oxide thin-film transistors (NZO TFTs) on flexible plastic substrates using magnetron sputtering. The effects of active layer thickness on the performance of NZO TFTs was investigated. We found that the channel layer thickness has a notable influence on the characteristics of NZO TFTs. The electrical characteristics of NZO TFTs reached the optimization when the active channel layer thickness was 71 nm, with a low off-current lower than 1 pA, a high on/off drain current ratio of , a high saturation mobility of 27.5 cm, a steeper subthreshold swing of 67 mV/decade, and a low threshold voltage of 1.88 V. It is demonstrated that NZO is a promising active channel layer materials for future transparent flexible displays.
Autors: Dedong Han;Lingling Huang;Wen Yu;Yingying Cong;Junchen Dong;Xing Zhang;Yi Wang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2017, volume: 64, issue:5, pages: 1997 - 2000
Publisher: IEEE
 
» Effects of Gd2O3 Gate Dielectric on Proton-Irradiated AlGaN/GaN HEMTs
Abstract:
AlGaN/GaN high electron mobility transistors (HEMTs) and MOS-HEMTs using Gd2O3 as gate dielectric were irradiated with 2-MeV protons up to fluence of cm−2. Results showed that proton irradiation causes a strong degradation in the Schottky gate devices, featured by more than three orders of magnitude increase in reverse leakage current, a 30% decrease in maximum drain current, and the same percentage of increase in ON-resistance, respectively. Scanning transmission electron microscopy showed that radiation induced a diffusion of Ni into Au in the gate and void formation, degrading the transistors’ characteristics. The Gd2O3 gate dielectric layer prevented this diffusion and void formation. MOS-HEMTs with Gd2O3 gate dielectric show 50% less decrease of performance under proton irradiation than Schottky gate HEMTs (conventional HEMTs). The trapping effects of Gd2O3 gate layer before and after irradiation are also discussed.
Autors: Z. Gao;M. F. Romero;A. Redondo-Cubero;M. A. Pampillón;E. San Andrés;F. Calle;
Appeared in: IEEE Electron Device Letters
Publication date: May 2017, volume: 38, issue:5, pages: 611 - 614
Publisher: IEEE
 
» Effects of Ni in Strontium Titanate Nickelate Thin Films for Flexible Nonvolatile Memory Applications
Abstract:
This paper investigated the performance of flexible resistive random access memory devices based on simple spin-coated sol–gel-derived strontium titanate nickelate (STN) thin films on polyethylene terephthalate substrate. A high on/off ratio of and a uniform current distribution were demonstrated. The strong bonding between bidentate ligands of nickel (II) acetylacetone and titanium metal ion enabled the chelation effect, which contributed to the stability of the STN thin film, especially for moisture resistivity. Fourier transform infrared spectroscopy analysis was utilized to examine the effects on the resistive switching behaviors after 90 days under an atmospheric environment according to the chelation effect of the STN thin films. The devices were fabricated on a flexible plastic substrate, and they exhibited excellent durability upon repeated bending tests. They demonstrated good potential application for flexible and low-cost memory devices.
Autors: Ke-Jing Lee;Yu-Chi Chang;Cheng-Jung Lee;Li-Wen Wang;Dei-Wei Chou;Te-Kung Chiang;Yeong-Her Wang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2017, volume: 64, issue:5, pages: 2001 - 2007
Publisher: IEEE
 
» Efficient Activity Detection in Untrimmed Video with Max-Subgraph Search
Abstract:
We propose an efficient approach for activity detection in video that unifies activity categorization with space-time localization. The main idea is to pose activity detection as a maximum-weight connected subgraph problem. Offline, we learn a binary classifier for an activity category using positive video exemplars that are “trimmed” in time to the activity of interest. Then, given a novel untrimmed video sequence, we decompose it into a 3D array of space-time nodes, which are weighted based on the extent to which their component features support the learned activity model. To perform detection, we then directly localize instances of the activity by solving for the maximum-weight connected subgraph in the test video's space-time graph. We show that this detection strategy permits an efficient branch-and-cut solution for the best-scoring-and possibly non-cubically shaped-portion of the video for a given activity classifier. The upshot is a fast method that can search a broader space of space-time region candidates than was previously practical, which we find often leads to more accurate detection. We demonstrate the proposed algorithm on four datasets, and we show its speed and accuracy advantages over multiple existing search strategies.
Autors: Chao Yeh Chen;Kristen Grauman;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: May 2017, volume: 39, issue:5, pages: 908 - 921
Publisher: IEEE
 
» Efficient Algorithms for the Identification of Top-$k$ Structural Hole Spanners in Large Social Networks
Abstract:
Recent studies show that individuals in a social network can be divided into different groups of densely connected communities, and these individuals who bridge different communities, referred to as structural hole spanners, have great potential to acquire resources/information from communities and thus benefit from the access. Structural hole spanners are crucial in many real applications such as community detections, diffusion controls, viral marketing, etc. In spite of their importance, little attention has been paid to them. Particularly, how to accurately characterize the structural hole spanners and how to devise efficient yet scalable algorithms to find them in a large social network are fundamental issues. In this paper, we study the top-k structural hole spanner problem. We first provide a novel model to measure the quality of structural hole spanners through exploiting the structural hole spanner properties. Due to its NP-hardness, we then devise two efficient yet scalable algorithms, by developing innovative filtering techniques that can filter out unlikely solutions as quickly as possible, while the proposed techniques are built up on fast estimations of the upper and lower bounds on the cost of an optimal solution and make use of articulation points in real social networks. We finally conduct extensive experiments to validate the effectiveness of the proposed model, and to evaluate the performance of the proposed algorithms using real world datasets. The experimental results demonstrate that the proposed model can capture the characteristics of structural hole spanners accurately, and the structural hole spanners found by the proposed algorithms are much better than those by existing algorithms in all considered social networks, while the running times of the proposed algorithms are very fast.
Autors: Wenzheng Xu;Mojtaba Rezvani;Weifa Liang;Jeffrey Xu Yu;Chengfei Liu;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: May 2017, volume: 29, issue:5, pages: 1017 - 1030
Publisher: IEEE
 
» Efficient and Confidentiality-Preserving Content-Based Publish/Subscribe with Prefiltering
Abstract:
Content-based publish/subscribe provides a loosely-coupled and expressive form of communication for large-scale distributed systems. Confidentiality is a major challenge for publish/subscribe middleware deployed over multiple administrative domains. Encrypted matching allows confidentiality-preserving content-based filtering but has high performance overheads. It may also prevent the use of classical optimizations based on subscriptions containment. We propose a support mechanism that reduces the cost of encrypted matching, in the form of a prefiltering operator using Bloom filters and simple randomization techniques. This operator greatly reduces the amount of encrypted subscriptions that must be matched against incoming encrypted publications. It leverages subscription containment information when available, but also ensures that containment confidentiality is preserved otherwise. We propose containment obfuscation techniques and provide a rigorous security analysis of the information leaked by Bloom filters in this case. We conduct a thorough experimental evaluation of prefiltering under a large variety of workloads. Our results indicate that prefiltering is successful at reducing the space of subscriptions to be tested in all cases. We show that while there is a tradeoff between prefiltering efficiency and information leakage when using containment obfuscation, it is practically possible to obtain good prefiltering performance while securing the technique against potential leakages.
Autors: Raphaël Barazzutti;Pascal Felber;Hugues Mercier;Emanuel Onica;Etienne Rivière;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: May 2017, volume: 14, issue:3, pages: 308 - 325
Publisher: IEEE
 
» Efficient Complex Root Tracing Algorithm for Propagation and Radiation Problems
Abstract:
An efficient complex root tracing algorithm for propagation and radiation problems is presented. The proposed approach is based on a discretization of Cauchy’s Argument Principle and its generalization to the space. Moreover, an engagement of the tracing process with a global root finding algorithm recently presented in the literature is performed. In order to confirm a validity and efficiency of the proposed technique, a few different types of structures have been analyzed.
Autors: Piotr Kowalczyk;Wojciech Marynowski;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2540 - 2546
Publisher: IEEE
 
» Efficient Digital Quadrature Transmitter Based on IQ Cell Sharing
Abstract:
In this paper, we proposed and designed a digitally configured versatile RF quadrature transmitter. The transmitter efficiency was enhanced by IQ cell sharing and the deactivation of cells of opposite phases. In simulation, these techniques were able to increase the average efficiency of the transmitter from 46.3% to 70.7% for a 6.9-dB PAPR LTE signal. Moreover, the number of power amplifying cells was halved, improving the total efficiency of the transmitter. The proposed transmitter was implemented in a 6-b configuration at 0.8 GHz using a 28-nm CMOS process. Furthermore, the performance of the transmitter was verified. The dynamic range of the measured output power was in the range −20.2 to 13.9 dBm, and the measured average output power was 6.97 dBm for the 6.9-dB PAPR LTE signal. The measured power-added efficiencies of the transmitter at the peak power and average power were 40.43% and 29.1%, respectively.
Autors: Hadong Jin;Dongsu Kim;Bumman Kim;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: May 2017, volume: 52, issue:5, pages: 1345 - 1357
Publisher: IEEE
 
» Efficient Gas Sensor Devices Based on Surface Engineered Oxygen Vacancy Controlled TiO2 Nanosheets
Abstract:
Systematic optimization of the surface attributes (structural and morphological) as well as the defect states [oxygen vacancies (OVs)], for achieving efficient alcohol sensing by TiO2 nanosheets, is the central focus of this paper. Variation in the surface roughness and the OVs of hydrothermally grown TiO2 nanosheets were achieved by varying the ethanol and water content in stepwise manner, keeping the NaOH concentrations in the electrolyte unchanged. Structural, morphological, and optical characterizations, such as field emission scanning electronmicroscopy and X-ray photoelectronspectroscopy, revealed that with increase in ethanol concentrations, surface roughness increased (at a particular water concentration), while at a fixed ethanol concentration, OVs increased with decrease in water concentrations. The sensor derived through the minimum water content and the maximum ethanol content offered the most promising sensor response owing to availability of the maximum amount of OVs with the highest surface roughness.
Autors: Basanta Bhowmik;Partha Bhattacharyya;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2017, volume: 64, issue:5, pages: 2357 - 2363
Publisher: IEEE
 
» Efficient Implementation for the AH FDTD Method With Iterative Procedure and CFS-PML
Abstract:
An efficient implementation for the associated Hermite finite-difference time-domain (AH FDTD) method with iterative procedure is proposed, which is an extension of previous works: the original and the paralleling-in-order-based AH FDTD methods. By introducing the alternating direction implicit method, the direct calculation of five-point matrix equation is replaced with iterative solving of tridiagonal matrices equations. For the 2-D case, only two tridiagonal matrixes need to be calculated in a full iterative cycle. In addition, the complex frequency shifted (CFS) perfectly matched layer (PML) is extended to the AH FDTD method and implemented together with this efficient solution scheme. Numerical examples show the superior computational performance of the proposed iterative procedure by comparison with the conventional FDTD method, the ADI FDTD method, and previous AH FDTD methods. The effectiveness of CFS-PML in AH FDTD is also verified.
Autors: Zheng-Yu Huang;Li-Hua Shi;Bin Chen;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2728 - 2733
Publisher: IEEE
 
» Efficient Privacy-Preserving Facial Expression Classification
Abstract:
This paper proposes an efficient algorithm to perform privacy-preserving (PP) facial expression classification (FEC) in the client-server model. The server holds a database and offers the classification service to the clients. The client uses the service to classify the facial expression (FaE) of subject. It should be noted that the client and server are mutually untrusted parties and they want to perform the classification without revealing their inputs to each other. In contrast to the existing works, which rely on computationally expensive cryptographic operations, this paper proposes a lightweight algorithm based on the randomization technique. The proposed algorithm is validated using the widely used JAFFE and MUG FaE databases. Experimental results demonstrate that the proposed algorithm does not degrade the performance compared to existing works. However, it preserves the privacy of inputs while improving the computational complexity by times and communication complexity by percent against the existing homomorphic cryptography based approach.
Autors: Yogachandran Rahulamathavan;Muttukrishnan Rajarajan;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: May 2017, volume: 14, issue:3, pages: 326 - 338
Publisher: IEEE
 
» Efficient Processing of Skyline Queries Using MapReduce
Abstract:
The skyline operator has attracted considerable attention recently due to its broad applications. However, computing a skyline is challenging today since we have to deal with big data. For data-intensive applications, the MapReduce framework has been widely used recently. In this paper, we propose the efficient parallel algorithm SKY-MR+ for processing skyline queries using MapReduce. We first build a quadtree-based histogram for space partitioning by deciding whether to split each leaf node judiciously based on the benefit of splitting in terms of the estimated execution time. In addition, we apply the dominance power filtering method to effectively prune non-skyline points in advance. We next partition data based on the regions divided by the quadtree and compute candidate skyline points for each partition using MapReduce. Finally, we check whether each skyline candidate point is actually a skyline point in every partition using MapReduce. We also develop the workload balancing methods to make the estimated execution times of all available machines to be similar. We did experiments to compare SKY-MR+ with the state-of-the-art algorithms using MapReduce and confirmed the effectiveness as well as the scalability of SKY-MR+.
Autors: Yoonjae Park;Jun-Ki Min;Kyuseok Shim;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: May 2017, volume: 29, issue:5, pages: 1031 - 1044
Publisher: IEEE
 
» Efficient Resource Constrained Scheduling Using Parallel Two-Phase Branch-and-Bound Heuristics
Abstract:
Branch-and-bound (B&B) approaches are widely investigated in resource constrained scheduling (RCS). However, due to the lack of approaches that can generate a tight schedule at the beginning of the search, B&B approaches usually start with a large initial search space, which makes the following search of an optimal schedule time-consuming. To address this problem, this paper proposes a parallel two-phase B&B approach that can drastically reduce the overall RCS time. This paper makes three major contributions: i) it proposes three partial-search heuristics that can quickly find a tight schedule to compact the initial search space; ii) it presents a two-phase search framework that supports the efficient parallel search of an optimal schedule; iii) it investigates various bound sharing and speculation techniques among collaborative tasks to further improve the parallel search performance at different search phases. The experimental results based on well-established benchmarks demonstrate the efficacy of our proposed approach.
Autors: Mingsong Chen;Yongxiang Bao;Xin Fu;Geguang Pu;Tongquan Wei;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: May 2017, volume: 28, issue:5, pages: 1299 - 1314
Publisher: IEEE
 
» Efficient Scalable Parallel Higher Order Direct MoM-SIE Method With Hierarchically Semiseparable Structures for 3-D Scattering
Abstract:
A novel fast scalable parallel algorithm is proposed for the solution of large 3-D scattering problems based on: 1) the double (geometrical and current-approximation) higher order (DHO) method of moments (MoM) in the surface integral equation (SIE) formulation and 2) a direct solver for dense linear systems utilizing hierarchically semiseparable (HSS) structures. Namely, an HSS matrix representation is used for compression, factorization, and solution of the system matrix. In addition, a rank-revealing QR decomposition for memory compression is used, with a stopping criterion in terms of the relative rank tolerance value. A method for geometrical preprocessing of the scatterers based on the cobblestone distance sorting technique is employed in order to enhance the HSS algorithm accuracy and parallelization. Numerical examples show how the accuracy of the DHO HSS-MoM-SIE method is easily controllable by using the relative tolerance for the matrix compression. Moreover, the examples demonstrate low memory consumption, as well as much faster simulation time, when compared to the direct LU decomposition. The method enables dramatically faster monostatic scattering computations than iterative solvers and reduced number of unknowns when compared to low-order discretizations. Finally, great scalability of the algorithm is demonstrated on more than one thousand processes.
Autors: Ana B. Manić;Aaron P. Smull;François-Henry Rouet;Xiaoye Sherry Li;Branislav M. Notaroš;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2467 - 2478
Publisher: IEEE
 
» Efficient sharing of optical resources in low-power optical networks-on-chip
Abstract:
With the ever-growing core counts in modern computing systems, networks-on-chip (NoCs) consume an increasing part of the power budget due to bandwidth and power density limitations of electrical interconnects. To maintain performance and power scaling, alternative technologies are required, with silicon photonics being a promising candidate thanks to high-bandwidth, lowenergy data transmission. To get the best of silicon photonics, sophisticated network designs are required to minimize static power overheads. In this paper, we propose Amon, a low-power optical NoC that decreases the number of μRings, wavelengths, and path losses to reduce power consumption. Amon performs destination checking prior to data transmission on an underlying control network, allowing the sharing of optical bandwidth. Compared to a wide range of state-of-the-art optical, hybrid, and electrical NoCs, Amon improves throughput-per-watt by at least 23% (up to 70%), while reducing power without latency overheads on both synthetic and realistic applications. For aggressive optical technology parameters, Amon considerably outperforms all alternative NoCs in terms of power, highlighting its increasing superiority as technology matures.
Autors: Sebastian Werner;Javier Navaridas;Mikel Luján;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: May 2017, volume: 9, issue:5, pages: 364 - 374
Publisher: IEEE
 
» Efficient Surgical Cutting with Position-Based Dynamics
Abstract:
Simulations of cuts on deformable bodies have been an active research subject for more than two decades. However, previous works based on finite element methods and mass spring meshes cannot scale to complex surgical scenarios. This article presents a novel method that uses position-based dynamics (PBD) for mesh-free cutting simulation. The proposed solutions include a method to efficiently render force feedback while cutting, an efficient heat diffusion model to simulate electrocautery, and a novel adaptive skinning scheme based on oriented particles.https://extras.computer.org/extra/mcg2017030024s1.mp4
Autors: Iago Berndt;Rafael Torchelsen;Anderson Maciel;
Appeared in: IEEE Computer Graphics and Applications
Publication date: May 2017, volume: 38, issue:3, pages: 24 - 31
Publisher: IEEE
 
» Elastic Functional Coding of Riemannian Trajectories
Abstract:
Visual observations of dynamic phenomena, such as human actions, are often represented as sequences of smoothly-varying features. In cases where the feature spaces can be structured as Riemannian manifolds, the corresponding representations become trajectories on manifolds. Analysis of these trajectories is challenging due to non-linearity of underlying spaces and high-dimensionality of trajectories. In vision problems, given the nature of physical systems involved, these phenomena are better characterized on a low-dimensional manifold compared to the space of Riemannian trajectories. For instance, if one does not impose physical constraints of the human body, in data involving human action analysis, the resulting representation space will have highly redundant features. Learning an effective, low-dimensional embedding for action representations will have a huge impact in the areas of search and retrieval, visualization, learning, and recognition. Traditional manifold learning addresses this problem for static points in the euclidean space, but its extension to Riemannian trajectories is non-trivial and remains unexplored. The difficulty lies in inherent non-linearity of the domain and temporal variability of actions that can distort any traditional metric between trajectories. To overcome these issues, we use the framework based on transported square-root velocity fields (TSRVF); this framework has several desirable properties, including a rate-invariant metric and vector space representations. We propose to learn an embedding such that each action trajectory is mapped to a single point in a low-dimensional euclidean space, and the trajectories that differ only in temporal rates map to the same point. We utilize the TSRVF representation, and accompanying statistical summaries of Riemannian trajectories, to extend existing coding methods such as PCA, KSVD and Label Consistent KSVD to Riemannian trajectories or more generally to Riemannian functions. We - how that such coding efficiently captures trajectories in applications such as action recognition, stroke rehabilitation, visual speech recognition, clustering and diverse sequence sampling. Using this framework, we obtain state-of-the-art recognition results, while reducing the dimensionality/ complexity by a factor of 100-250x. Since these mappings and codes are invertible, they can also be used to interactively-visualize Riemannian trajectories and synthesize actions.
Autors: Rushil Anirudh;Pavan Turaga;Jingyong Su;Anuj Srivastava;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: May 2017, volume: 39, issue:5, pages: 922 - 936
Publisher: IEEE
 
» Electrical and Interfacial Properties of GaAs MOS Capacitors With La-Doped ZrON as Interfacial Passivation Layer
Abstract:
GaAs MOS capacitors with ZrTiON high- gate dielectric and ZrLaON or ZrON as interfacial passivation layer (IPL) are fabricated, and their electrical properties are investigated. As compared with a control sample without IPL, improved interfacial quality and electrical properties are obtained for both samples, with the ZrTiON/ZrLaON/GaAs device, exhibiting the lowest interface-state density ( cm eV, smallest gate leakage current density ( A cm at V), and largest equivalent dielectric constant (25.1). All of these should be attributed to the fact that incorporating La into the ZrON IPL can: first, passivate its defects and, second, enhance the blocking role of the IPL against the Ti/O in-diffusion to the GaAs substrate and the Ga/As out-diffusion to the high-, thus resulting in an obvious reduction of relevant defects in the gate stack and also suppressing the formation of unstable Ga/As oxides and As–As dimer at the GaAs surface to obtain a much improved dielectric/GaAs interface.
Autors: Han-Han Lu;Jing-Ping Xu;Lu Liu;Pui-To Lai;Wing-Man Tang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: May 2017, volume: 64, issue:5, pages: 2179 - 2184
Publisher: IEEE
 
» Electromagnetic Energy Harvesting Using Full-Wave Rectification
Abstract:
This paper presents a new approach to realizing full-wave rectification for electromagnetic energy harvesting. Instead of using one antenna to feed one rectifier circuit, we propose utilizing two antennas connected to one rectifier to form a full-wave rectenna. This balanced configuration allows the received power to be rectified and transferred to a dc load between two antennas, making it very easy to channel the harvested power in rectenna arrays. The proposed concept is demonstrated in the microwave regime using an array of full-wave rectennas optimized for 2.45 GHz. The full-wave rectenna array is compared with an array of half-wave rectennas that occupy the same footprint and are optimized to maximize power absorption at the same frequency. Measurements showed that the proposed full-wave rectifier performed better than the half-wave rectifier and achieved 74% radiation-to-dc conversion efficiency. Here, without loss of generality, the proposed concept is demonstrated using T-matched dipole antennas at a specific frequency, but the concept can be applied to other antenna types and other frequencies.
Autors: Faruk Erkmen;Thamer S. Almoneef;Omar M. Ramahi;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: May 2017, volume: 65, issue:5, pages: 1843 - 1851
Publisher: IEEE
 
» Electromagnetic Fields Generated Above a Shallow Sea by a Submerged Horizontal Electric Dipole
Abstract:
Great attention has been paid to the propagation of electromagnetic (EM) waves across the sea surface due to its important applications. Most of the previous research, however, focus on the half-space model illustrating the deep sea environment. In this communication, by taking into account the presence of a seafloor, the EM fields generated above shallow sea by a submerged horizontal electric dipole have been investigated theoretically and experimentally with a three-layer model. A set of formulas for EM fields in air expressed by Sommerfeld integrals are derived with recursive propagation approach, and the fields are computed using a complementary numerical integration technique. The effects of frequency, sea depth, seafloor conductivity, and receiver height on the fields are discussed. An experiment was conducted on shallow sea, and the test results agree well with theoretical predication in the quasi-near range. A transmission distance over 3 km above the sea surface was realized with reasonable transmitting power, which shows the potential of our theoretical model for applications in shallow sea environment.
Autors: Jinhong Wang;Bin Li;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2707 - 2712
Publisher: IEEE
 
» Electromagnetic Performance Analysis of Graded Dielectric Inhomogeneous Streamlined Airborne Radome
Abstract:
Streamlined nosecone radomes for airborne applications have to cater to high-end electromagnetic (EM) performance requirements of fire control radar antenna system. In this regard, the EM performance analysis of an ogival radome based on novel graded dielectric inhomogeneous wall structure is presented. The radome wall considered here consists of seven dielectric layers cascaded in such a way that the middle layer has maximum dielectric parameters (dielectric constant and electric loss tangent) and on either side, dielectric parameters of the layers decrease in a graded (or stepwise) manner. Further, the outer surface of the radome wall is coated with an antistatic and antierosion radome paint. The EM performance parameters of the radome enclosing an X-band slotted waveguide planar array antenna (center frequency: 10 GHz; bandwidth: 1 GHz) are computed based on 3-D ray tracing in conjunction with aperture integration method. The study shows that the proposed graded dielectric inhomogeneous streamlined radome is an excellent choice for airborne applications as compared to airborne radomes based on conventional constant thickness radome designs and variable thickness radome (VTR) designs. Further, it circumvents the constraints on fabrication that occur in streamlined VTR designs.
Autors: P. S. Mohammed Yazeen;C. V. Vinisha;S. Vandana;M. Suprava;Raveendranath U. Nair;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: May 2017, volume: 65, issue:5, pages: 2718 - 2723
Publisher: IEEE
 
» Electronic license plates for drones [Spectral Lines]
Abstract:
In late 2015, mandatory drone registration went into effect in the United States. Since then, anyone who wants to fly a drone (or model aircraft) weighing over 0.55 pound (0.25 kilogram) must register with the U.S. Federal Aviation Administration to receive a unique identification number. This number needs to be placed on the drone, but there is no requirement for the tiny aircraft to broadcast signals to allow for remote identification. That might change in the future.
Autors: David Schneider;
Appeared in: IEEE Spectrum
Publication date: May 2017, volume: 54, issue:5, pages: 8 - 8
Publisher: IEEE
 

Publication archives by date

  2017:   January     February     March     April     May     June     July     August     September     October     November     December    

  2016:   January     February     March     April     May     June     July     August     September     October     November     December    

  2015:   January     February     March     April     May     June     July     August     September     October     November     December    

  2014:   January     February     March     April     May     June     July     August     September     October     November     December    

  2013:   January     February     March     April     May     June     July     August     September     October     November     December    

  2012:   January     February     March     April     May     June     July     August     September     October     November     December    

  2011:   January     February     March     April     May     June     July     August     September     October     November     December    

  2010:   January     February     March     April     May     June     July     August     September     October     November     December    

  2009:   January     February     March     April     May     June     July     August     September     October     November     December    

 
0-C     D-L     M-R     S-Z