Electrical and Electronics Engineering publications abstract of: 10-2017 sorted by title, page: 16

» Single-Shot ${\text{T}}_{{2}}$ Mapping Through OverLapping-Echo Detachment (OLED) Planar Imaging
Abstract:
Objective: Develop a reliable single-shot mapping method with extra robustness to motion and the potential for real-time dynamic and quantitative MR imaging. Methods: A single-shot mapping sequence was proposed based on spin-echo planar imaging acquisition scheme. Two overlapped echo signals with different weighting were obtained simultaneously by using two small flip-angle excitation pulses and corresponding echo-shifting gradients. A detachment algorithm based on structure similarity constraint was proposed to separate the two echo signals. mapping was obtained from the two separated echo signals. Results: The robustness and efficiency of the method were demonstrated through simulation, phantom experiments, and human brain measurements. Conclusion: Reliable mapping can be obtained within milliseconds even under continuous head motion. Significance: Reliable mapping was achieved with a single shot for the first time. The proposed method will facilitate real-time dynamic and quantitative MR imaging.
Autors: Congbo Cai;Yiqing Zeng;Yuchuan Zhuang;Shuhui Cai;Lin Chen;Xinghao Ding;Lijun Bao;Jianhui Zhong;Zhong Chen;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Oct 2017, volume: 64, issue:10, pages: 2450 - 2461
Publisher: IEEE
 
» Single-Stage Buck-Derived LED Driver With Improved Efficiency and Power Factor Using Current Path Control Switches
Abstract:
This paper proposes a single-stage light-emitting diode (LED) driver based on an inverted buck topology, using current path control switches. The proposed circuit consists of a control circuit, a bridge diode, and an inverted buck converter with multiple switches connected to the LED segments in parallel. Whereas the typical buck LED driver operates with a fixed LED forward voltage, the proposed driver operates with a variable LED forward voltage, according to the input voltage level. Because of this capability to adjust the LED forward voltage, it can reduce the current ripple and the switching frequency with a small inductance value. In addition, it enables operation with LED lamps of a wide voltage range, while simultaneously achieving small dead-angles. The detailed operation principles are described, and the design considerations for the proposed driver are discussed. The proposed driver circuit and control operation are verified experimentally using a 7 W hardware prototype with four LED segments. The obtained experimental results show that under a 110 Vrms input voltage, the proposed driver achieves a power factor of 0.94 with a small dead-angle and an efficiency of 94%.
Autors: Jong-Bok Baek;Suyong Chae;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7852 - 7861
Publisher: IEEE
 
» Sinogram Blurring Matrix Estimation From Point Sources Measurements With Rank-One Approximation for Fully 3-D PET
Abstract:
An accurate system matrix is essential in positron emission tomography (PET) for reconstructing high quality images. To reduce storage size and image reconstruction time, we factor the system matrix into a product of a geometry projection matrix and a sinogram blurring matrix. The geometric projection matrix is computed analytically and the sinogram blurring matrix is estimated from point source measurements. Previously, we have estimated a 2-D blurring matrix for a preclinical PET scanner. The 2-D blurring matrix only considers blurring effects within a transaxial sinogram and does not compensate for inter-sinogram blurring effects. For PET scanners with a long axial field of view, inter-sinogram blurring can be a major problem influencing the image quality in the axial direction. Hence, the estimation of a 4-D blurring matrix is desirable to further improve the image quality. The 4-D blurring matrix estimation is an ill-conditioned problem due to the large number of unknowns. Here, we propose a rank-one approximation for each blurring kernel image formed by a row vector of the sinogram blurring matrix to improve the stability of the 4-D blurring matrix estimation. The proposed method is applied to the simulated data as well as the real data obtained from an Inveon microPET scanner. The results show that the newly estimated 4-D blurring matrix can improve the image quality over those obtained with a 2-D blurring matrix and requires less point source scans to achieve similar image quality compared with an unconstrained 4-D blurring matrix estimation.
Autors: Kuang Gong;Jian Zhou;Michel Tohme;Martin Judenhofer;Yongfeng Yang;Jinyi Qi;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 2179 - 2188
Publisher: IEEE
 
» SIR Analysis of OFDM and GFDM Waveforms With Timing Offset, CFO, and Phase Noise
Abstract:
In this paper, we analyze the impacts of timing offset (TO), carrier frequency offset (CFO), and phase noise in orthogonal frequency division multiplexing (OFDM) and generalized frequency division multiplexing (GFDM) waveforms. As TO can be classified into four cases depending on the direction of offset, we provide the analysis of signal-to-interference ratio (SIR) for each of the cases when phase noise and synchronization errors of the desired user occur in frequency selective channel. We also propose the receiver filter for GFDM systems that is optimized to maximize SIR with CFO in additive white Gaussian noise channel. Simulation results show that GFDM is more sensitive to CFO than OFDM. We also confirm that GFDM systems using proposed receiver filter are robust against CFO compared with conventional systems.
Autors: Byungju Lim;Young-Chai Ko;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6979 - 6990
Publisher: IEEE
 
» Size-Dependent Multiple-Scattering Effects of Mesoporous TiO2 Beads Distinguished by Optical Coherence Tomography
Abstract:
In this study, we propose a new analysis method using optical coherence tomography to further use the diffusive reflectance measurement to quantify the contribution of the size-dependent multiple-scattering effects of mesoporous TiO2 beads. The diffusive reflectance results from the complex interactions between light and the scattering particles, and influences the slopes of the associated depth-dependent A-scan profiles, which can be fitted based on the extended Huygens–Fresnel model to quantify the contribution ratio of the multiple-scattering effects to the single scattering effects. The mesoporous TiO2 beads with average diameter of 300 nm show higher contribution percentage of multiple-scattering effects inducing reflectivity enhancement in the longer wavelength region. The contribution ratio of multiple-scattering effects can be distinguished numerically, and is enhanced from 5% to 40% and then decreased to 20% for the bead diameters ranging from 20 to 300 nm and then to 500 nm, respectively. The calculated scattering coefficients are 13.5 ± 0.6 mm–1, 16.5 ± 0.6 mm–1, 20.2 ± 0.6 mm–1, and 18.5 ± 0.6 mm–1, respectively.
Autors: Ling-Hsuan Tsai;Po Nien Yang;Yen-Chen Shih;King-Fu Lin;Chung-Chih Wu;Hoang Yang Lin;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Small-Signal Stability Assessment of Power Electronics Based Power Systems: A Discussion of Impedance- and Eigenvalue-Based Methods
Abstract:
This paper investigates the small-signal stability of power electronics-based power systems in frequency domain. A comparison between the impedance-based and the eigenvalue-based stability analysis methods is presented. A relation between the characteristics equation of the eigenvalues and poles and zeros of the minor-loop gain from the impedance-based analysis have been derived analytically. It is shown that both stability analysis methods can effectively determine the stability of the system. In the case of the impedance-based method, a low phase-margin in the Nyquist plot of the minor-loop gain indicates that the system can exhibit harmonic oscillations. A weakness of the impedance method is the limited observability of certain states given its dependence on the definition of local source-load subsystems, which makes it necessary to investigate the stability at different subsystems. To address this limitation, the paper discusses critical locations where the application of the method can reveal the impact of a passive component or a controller gain on the stability. On the other hand, the eigenvalue-based method, being global, can determine the stability of the entire system; however, it cannot unambiguously predict sustained harmonic oscillations in voltage source converter (VSC) based high voltage dc (HVdc) systems caused by pulse-width modulation (PWM) switching. To generalize the observations, the two methods have been applied to dc–dc converters. To illustrate the difference and the relation between the two-methods, the two stability analysis methods are then applied to a two-terminal VSC-based HVdc system as an example of power electronics-based power systems, and the theoretical analysis has been further validated by simulation and experiments.
Autors: Mohammad Amin;Marta Molinas;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 5014 - 5030
Publisher: IEEE
 
» Smart Gait-Aid Glasses for Parkinson's Disease Patients
Abstract:
Parkinson's disease (PD) is a chronic progressive disease caused by loss of dopaminergic neurons in the substantia nigra, degenerating the nervous system of a patient over time. Freezing of gait (FOG), which is a form of akinesia, is a symptom of PD. Meanwhile, recent studies show that the gait of PD patients experiencing FOG can be significantly improved by providing the regular visual or auditory patterns for the patients. In this paper, we propose a gait-aid system built upon smart glasses. Our system continuously monitors the gait and so on of a PD patient to detect FOG, and upon detection of FOG it projects visual patterns on the glasses as if the patterns were actually on the floor. Conducting experiments involving ten PD patients, we demonstrate that our system achieves the accuracy of 92.86 in detecting FOG episodes and that it improves the gait speed and stride length of PD patients by 15.3 37.2% and 18.7  31.7%, respectively.
Autors: DaeHan Ahn;Hyerim Chung;Ho-Won Lee;Kyunghun Kang;Pan-Woo Ko;Nam Sung Kim;Taejoon Park;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Oct 2017, volume: 64, issue:10, pages: 2394 - 2402
Publisher: IEEE
 
» Smartphone-Based Vehicle Telematics: A Ten-Year Anniversary
Abstract:
Just as it has irrevocably reshaped social life, the fast growth of smartphone ownership is now beginning to revolutionize the driving experience and change how we think about automotive insurance, vehicle safety systems, and traffic research. This paper summarizes the first ten years of research in smartphone-based vehicle telematics, with a focus on user-friendly implementations and the challenges that arise due to the mobility of the smartphone. Notable academic and industrial projects are reviewed, and system aspects related to sensors, energy consumption, and human–machine interfaces are examined. Moreover, we highlight the differences between traditional and smartphone-based automotive navigation, and survey the state of the art in smartphone-based transportation mode classification, vehicular ad hoc networks, cloud computing, driver classification, and road condition monitoring. Future advances are expected to be driven by improvements in sensor technology, evidence of the societal benefits of current implementations, and the establishment of industry standards for sensor fusion and driver assessment.
Autors: Johan Wahlström;Isaac Skog;Peter Händel;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Oct 2017, volume: 18, issue:10, pages: 2802 - 2825
Publisher: IEEE
 
» Social Media: New Perspectives to Improve Remote Sensing for Emergency Response
Abstract:
Remote sensing is a powerful technology for Earth observation (EO), and it plays an essential role in many applications, including environmental monitoring, precision agriculture, resource managing, urban characterization, disaster and emergency response, etc. However, due to limitations in the spectral, spatial, and temporal resolution of EO sensors, there are many situations in which remote sensing data cannot be fully exploited, particularly in the context of emergency response (i.e., applications in which real/near-real-time response is needed). Recently, with the rapid development and availability of social media data, new opportunities have become available to complement and fill the gaps in remote sensing data for emergency response. In this paper, we provide an overview on the integration of social media and remote sensing in time-critical applications. First, we revisit the most recent advances in the integration of social media and remote sensing data. Then, we describe several practical case studies and examples addressing the use of social media data to improve remote sensing data and/or techniques for emergency response.
Autors: Jun Li;Zhi He;Javier Plaza;Shutao Li;Jinfen Chen;Henglin Wu;Yandong Wang;Yu Liu;
Appeared in: Proceedings of the IEEE
Publication date: Oct 2017, volume: 105, issue:10, pages: 1900 - 1912
Publisher: IEEE
 
» Socially Aware Energy-Efficient Mobile Edge Collaboration for Video Distribution
Abstract:
To relieve the current overload of cellular networks caused by the continuously growing multimedia service, mobile edge collaboration, which exploits edge users to distribute videos for base station (BS), provides an effective way to share the heavy BS load. With the emergence of mobile edge technologies for Internet-of-Things applications, such as device to device and machine to machine, how to exploit users’ social characteristics and mobility to minimize the number of transmissions of BS and how to improve the quality of experience of users have become the key challenges. In this paper, we study two aspects that are critical to these issues. One is the two-step detection mechanism, namely the establishment of virtual communities and collaborative clusters. Specifically, we take into consideration user preference for content and location. First of all, a virtual community is established, which exploits the coalition game based on the user's preference list to dynamically divide users into multiple communities. Then, to take full advantage of the temporary link established between users, a grid-based clustering method is proposed to manage the video requesting users. On the other hand, we propose a scalable video coding sharing scheme based on user's social attributes. This approach makes video distribution more flexible at the edge of mobile network through collaboration among users, and effectively reduces transmission energy consumption of transmitters. Numerical results show that the proposed mechanism can not only effectively alleviate the BS load, but also dramatically improve the reliability and adaptability of video distribution.
Autors: Dapeng Wu;Qianru Liu;Honggang Wang;Dalei Wu;Ruyan Wang;
Appeared in: IEEE Transactions on Multimedia
Publication date: Oct 2017, volume: 19, issue:10, pages: 2197 - 2209
Publisher: IEEE
 
» Solar Flare TDOA Navigation Method Using Direct and Reflected Light for Mars Exploration
Abstract:
In the capture period of deep space exploration, three traditional celestial navigation methods including the direction, velocity, and distance measurements cannot completely meet the requirement of navigation accuracy due to ephemeris errors. To solve this problem, considering the fact that some impulses exist in solar light irradiance profile due to solar flares, we propose the solar flare time difference of arrival (TDOA) measurement method, which exploits these impulses to measure the position of the spacecraft. As the time of arrival (TOA) of solar flare cannot be predicted, we cannot use the solar flare TOA directly. The Mars light irradiance variation is related to the solar one, as the Mars light is the solar light filtered by the Martian atmosphere absorption filter. Based on this theory, the solar flare TDOA measurement method using direct and reflected light is developed. In this method, two solar flare TOAs are obtained by the spacecraft. One is from the sun directly. The other is the corresponding TOA reflected by Mars. Their difference is the TDOA measurement. In addition, we also propose two alternative schemes. One uses the solar light instead of flare if solar flares do not occur in the capture period, and the other adopts Phobos as the reflected point instead of Mars to solve the Martian atmospheric absorption. The traditional direction measurement-based navigation method can provide highly accurate navigation information at the tangential direction in the capture period. However, its accuracy at the radial direction is very low. Fortunately, the solar flare TDOA measurement method offsets this problem. To get highly accurate navigation information, the solar flare TDOA measurement and the Mars direction measurement are coupled into the solar flare TDOA/Mars direction integrated navigation system. We present simulation results that demonstrate the feasibility and effectiveness of the solar flare TDOA measurement method. Compared to the traditional- direction measurement-based navigation method, the solar flare TDOA/Mars direction integrated navigation can provide higher positioning accuracy, especially the radial component.
Autors: Jin Liu;Jian-Cheng Fang;Gang Liu;Jin Wu;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2469 - 2484
Publisher: IEEE
 
» Solid-State Pulse-Forming Modules by Utilizing the 2-D Electrode Manufacturing Technology
Abstract:
Nowadays, most of solid-state circuits are fabricated through the application of the 2-D electrode manufacturing technology (printed circuit). In this paper, solid-state pulse-forming modules using 2-D electrode manufacturing technology are presented to produce long pulse duration while less space volume is being occupied. First, on a glass–ceramic (dielectric constant 225) substrate with the dimension of mm, as meander line is the usual delay-line circuit in printed circuit boards, the meander pulse-forming line is used to deliver a high-voltage pulse with pulse duration longer than 120 ns by simulation and test validation. Furthermore, we also discuss the double parallel meander-line and the “V” shaped meander-line in this section. Second, with the same substrate, the LC pulse-forming module is used to generate the high-power pulse with good square pulse quality. By changing the inductance L, this module can be adjusted to deliver pulses with different durations. Third, planar concentric ring PFL is proposed with simulation analysis. In simulation, the planar concentric ring PFL is designed using an attractive storage medium—Barium Titanate (BaTiO3 base- ceramics (dielectric constant ~1000). At last, a compact PFL based on the structure of multilayer ceramic capacitor is introduced, and can generate a quasi-square pulse in simulation. These various types of solid-state pulse-forming modules may be the potential component in the compact pulsed power systems to generate high-voltage, long-duration pulses.
Autors: Langning Wang;Yongsheng Jia;Qiang Li;Jinliang Liu;Yongfeng Qiu;Xu Chu;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2667 - 2673
Publisher: IEEE
 
» Solution-Processed Complementary Resistive Switching Arrays for Associative Memory
Abstract:
Complementary resistive switches (CRS) based on back-to-back nanofilamentary resistive RAM devices have been fabricated by an all-solution-processed method, employing inkjet-printed Ag and Au contacts and a spin-coated sol–gel zirconium oxide dielectric layer. The devices demonstrate electrical switching behavior below 3 V, stable on-state windows, reasonable cycle lifetimes, and can be implemented in memory arrays with no crosstalk during addressing. For reliable operation and high yields of the CRS devices, printing and annealing processes were carefully optimized to eliminate the coffeering effect on the bottom electrode, and produce a pin-hole free dielectric. The arrays are fully pulse programmable and are able to retain their state for > s. Additionally, the arrays can be operated as associative or content addressable, memory for pattern matching applications, which is demonstrated through a basic hamming distance mapping measurement for different stored data states.
Autors: Jeremy Smith;Seungjun Chung;Jaewon Jang;Carlos Biaou;Vivek Subramanian;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4310 - 4316
Publisher: IEEE
 
» Solution-Processed SrOx-Gated Oxide Thin-Film Transistors and Inverters
Abstract:
In this paper, high-k strontium oxide (SrOx) dielectric thin films were fabricated using simple and low-cost solution process. The formation and properties of SrOx thin films annealed at various temperatures (400 °C, 500 °C, 600 °C, and 700 °C) were investigated using numbers of characterization techniques. The electrical analysis indicates that the insulating properties of SrOx thin films were improved with increasing annealing temperature. The post-annealing at temperatures higher than 400 °C enables the SrOx thin film, exhibiting low-leakage current density of ~10−8 A cm−2 at 3 V and the areal capacitance larger than 350 nF cm−2 at 20 Hz. To further explore the possible applications of solution-processed high-k SrOx thin films for thin-film transistors (TFTs), the indium oxide (In2O3) TFTs based on SrOx thin films were integrated for testing. The optimized In2O3/SrOx TFT exhibits high performance with an average field-effect mobility of 5.61 cm2 V−1 s−1, a small subthreshold swing of 110 mV dec−1, and a large on/off current ratio of 107. To demonstrate the potential of In2O3/SrOx TFT toward more complex logic applications, the unipolar inverter was further constructed and exhibited a high gain of 9.7. Importantly, all these device parameters were obtained at an ultralow operating voltage of 3 V, which represents a step toward portable, battery-driven, and low-power consumption electronics and circuits.
Autors: Caixuan Fan;Ao Liu;You Meng;Zidong Guo;Guoxia Liu;Fukai Shan;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4137 - 4143
Publisher: IEEE
 
» Some New Results on Sample Path Optimality in Ergodic Control of Diffusions
Abstract:
We present some new results on sample path optimality for the ergodic control problem of a class of nondegenerate diffusions controlled through the drift. The hypothesis most often used in the literature to ensure the existence of an almost sure sample path optimal stationary Markov control requires finite second moments of the first hitting times of bounded domains over all admissible controls. We show that this can be considerably weakened: may be replaced with , thus reducing the required rate of convergence of averages from polynomial to logarithmic. A Foster–Lyapunov condition that guarantees this is also exhibited. Moreover, we study a large class of models that are neither uniformly stable nor have a near-monotone running cost, and we exhibit sufficient conditions for the existence of a sample path optimal stationary Markov control.
Autors: Ari Arapostathis;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5351 - 5356
Publisher: IEEE
 
» Some Repeated-Root Constacyclic Codes Over Galois Rings
Abstract:
Codes over Galois rings have been studied extensively during the last three decades. Negacyclic codes over of length have been characterized: the ring is a chain ring. Furthermore, these results have been generalized to -constacyclic codes for any unit of the form , . In this paper, we study more general cases and investigate all cases, where is a chain ring. In particular, the necessary and sufficient conditions for the ring to be a chain ring are obtained. In addition, by using this structure we investigate all -constacyclic codes over when is a chain ring. The necessary and sufficient conditions for the existence of self-orthogonal and self-dual -constacyclic codes are also provided. Among others, for any prime , the structure of is used to establish the Hamming and homogeneous distances of -constacyclic codes.
Autors: Hongwei Liu;Youcef Maouche;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6247 - 6255
Publisher: IEEE
 
» Sparse Recovery in Magnetic Resonance Imaging With a Markov Random Field Prior
Abstract:
Recent research in compressed sensing of magnetic resonance imaging (CS-MRI) emphasizes the importance of modeling structured sparsity, either in the acquisition or in the reconstruction stages. Subband coefficients of typical images show certain structural patterns, which can be viewed in terms of fixed groups (like wavelet trees) or statistically (certain configurations are more likely than others). Wavelet tree models have already demonstrated excellent performance in MRI recovery from partial data. However, much less attention has been given in CS-MRI to modeling statistically spatial clustering of subband data, although the potentials of such models have been indicated. In this paper, we propose a practical CS-MRI reconstruction algorithm making use of a Markov random field prior model for spatial clustering of subband coefficients and an efficient optimization approach based on proximal splitting. The results demonstrate an improved reconstruction performance compared with both the standard CS-MRI methods and the recent related methods.
Autors: Marko Panić;Jan Aelterman;Vladimir Crnojević;Aleksandra Pižurica;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 2104 - 2115
Publisher: IEEE
 
» Sparse Tensor-Based Dimensionality Reduction for Hyperspectral Spectral–Spatial Discriminant Feature Extraction
Abstract:
This letter explores a spectral–spatial tensor-based dimensionality reduction (DR) method to cope with hyperspectral image (HSI) feature extraction and classification. This method uses the Gabor filter banks as the bias spectral–spatial feature hybrider and further integrates the tensor-based alignment strategy for the discriminant locality with sparse factorization by extracting optimal spectral–spatial features and simultaneously maintaining structural relevance. Comparative experimental results with two real HSIs demonstrate that the proposed DR method has a considerable advantage over other traditional feature extraction methods.
Autors: Zhi Liu;Bo Tang;Xiaofu He;Qingchen Qiu;Hongjun Wang;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1775 - 1779
Publisher: IEEE
 
» Sparse-Aware Minimum Mean Square Error Detector for MIMO Systems
Abstract:
In this letter, we propose a novel detector, called the sparse-aware minimum mean square error (SA-MMSE) detector, to improve detection performance for multiple input multiple output (MIMO) systems. We first convert a conventional MIMO system into a sparse system via the symbol error vector obtained from a linear detector. Then, we develop a new sparse refining method, which has a similar structure as the linear MMSE detector, to improve the detection performance. The proposed SA-MMSE detector can be performed iteratively and has low complexity similar to that of the parallel interference cancellation (PIC). Simulation results show that the SA-MMSE detector outperforms the compressive-sensing-based detector and PIC with a similar complexity, especially when the numbers of users and antennas become large.
Autors: Rong Ran;Jiaheng Wang;Seong Keun Oh;Song Nam Hong;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2214 - 2217
Publisher: IEEE
 
» Spatial Event Forecasting in Social Media With Geographically Hierarchical Regularization
Abstract:
Social media has been utilized as a significant surrogate for spatial societal event forecasting. The accuracy and discernibility of a spatial event forecasting model are two key concerns, as they determine how accurate and how detailed the model’s predictions will be. Existing research focuses almost exclusively on the accuracy alone, seldom considering the accuracy and discernibility simultaneously because this would require a considerably more sophisticated model while suffering from several challenges, namely: 1) the precise formulation of the tradeoff between accuracy and discernibility; 2) the scarcity of social media data with a high spatial resolution; and 3) the characterization of spatial correlation and heterogeneity. This paper proposes a novel feature learning framework that concurrently addresses all the above challenges by formulating prediction tasks for different locations with different spatial resolutions, allowing the heterogeneous relationships among the tasks to be characterized. This characterization is then integrated into our new models based on multitask learning, with parameters optimized by our proposed algorithm based on the alternative direction method of multipliers (ADMM) and dynamic programming. Extensive experimental evaluations performed on several data sets from different domains demonstrated the effectiveness of our proposed approach.
Autors: Liang Zhao;Junxiang Wang;Feng Chen;Chang-Tien Lu;Naren Ramakrishnan;
Appeared in: Proceedings of the IEEE
Publication date: Oct 2017, volume: 105, issue:10, pages: 1953 - 1970
Publisher: IEEE
 
» Spatial Technology and Social Media in Remote Sensing: A Survey
Abstract:
The rapid development of social media data and the associated growth in volume, velocity, and variety has fostered the idea of using these data to guide traditional remote sensing image retrieval and information extraction tasks. Although important progress has been made in recent years in harvesting spatial and temporal data from social media, the exploitation of these data for decision making still needs further investigation, particularly in the context of its integration with remote sensing and geographic information systems. In this paper, we first discuss the relation between localization techniques and spatial technologies, pointing out their similarities and differences. Then, we provide a discussion on location analysis of social media data, and the fusion of multiple data sources, with specific attention to the integration of social media content (including localization) with remote sensing-based spatial technologies. Next, we provide specific examples addressing the use of social media data to perform information extraction from large remote sensing data repositories. Although significant possibilities for the integration of localization and spatial technologies can be seen in the examples provided, our survey suggests that the convergence of remote sensing and social media data will continue to deeply transform these technologies.
Autors: Jun Li;Jón Atli Benediktsson;Bing Zhang;Tao Yang;Antonio Plaza;
Appeared in: Proceedings of the IEEE
Publication date: Oct 2017, volume: 105, issue:10, pages: 1855 - 1864
Publisher: IEEE
 
» Spatial Technology and Social Media [Scanning the Issue]
Abstract:
The significant development of social media over the past decade has been complemented by the rise of spatial technologies to provide new mapping mechanisms that allow users engage with online information services and also with each other in an unprecedented way. Users of these technologies now provide a comprehensive geosocial overlay of the physical environment of the planet.
Autors: Antonio Plaza;Jón Atli Benediktsson;Jun Li;Tao Yang;Bing Zhang;
Appeared in: Proceedings of the IEEE
Publication date: Oct 2017, volume: 105, issue:10, pages: 1851 - 1854
Publisher: IEEE
 
» Spatial Technology and Social Media [Scanningthe Issue]
Abstract:
The significant development of social media over the past decade has been complemented by the rise of spatial technologies to provide new mapping mechanisms that allow users engage with online information services and also with each other in an unprecedented way. Users of these technologies now provide a comprehensive geosocial overlay of the physical environment of the planet.
Autors: Antonio Plaza;Jón Atli Benediktsson;Jun Li;Tao Yang;Bing Zhang;
Appeared in: Proceedings of the IEEE
Publication date: Oct 2017, volume: 105, issue:10, pages: 1851 - 1854
Publisher: IEEE
 
» Spatially Adaptive Column Fixed-Pattern Noise Correction in Infrared Imaging System Using 1D Horizontal Differential Statistics
Abstract:
In this paper we present a novel non-uniformity correction (NUC) method to remove column fixed-pattern noise (FPN), which is introduced by non-uniformity of on-chip column-parallel readout circuit in uncooled infrared focal plane array. We first define a new image statistic measurement, which is named as 1D horizontal differential statistics, to differentiate column FPN from structural edges, and further propose a filtering scheme to adaptively compute noise terms in structure and non-structure regions by applying different correction models. The proposed NUC technique combines the advantages of global- and local-based correction methods, thus can effectively eliminate column FPN without losing original thermal details. The performance of the proposed method is systematically evaluated, and is compared with the state-of-the-art column FPN correction solutions using realistic infrared images.
Autors: Yanpeng Cao;Zewei He;Jiangxin Yang;Yanlong Cao;Michael Ying Yang;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 13
Publisher: IEEE
 
» Spatially Coupled Turbo-Like Codes
Abstract:
In this paper, we introduce the concept of spatially coupled turbo-like codes (SC-TCs) as the spatial coupling of a number of turbo-like code ensembles. In particular, we consider the spatial coupling of parallel concatenated codes, introduced by Berrou et al., and that of serially concatenated codes (SCCs), introduced by Benedetto et al. Furthermore, we propose two extensions of braided convolutional codes (BCCs), and a class of turbo-like codes which have an inherent spatially coupled structure, to higher coupling memories, and show that these yield improved belief propagation (BP) thresholds as compared with the original BCC ensemble. We derive the exact density evolution (DE) equations for SC-TCs and analyze their asymptotic behavior on the binary erasure channel. We also consider the construction of families of rate-compatible SC-TC ensembles. Our numerical results show that the threshold saturation of the BP decoding threshold to the maximum a posteriori threshold of the underlying uncoupled ensembles occurs for large enough coupling memory. The improvement of the BP threshold is especially significant for SCCs and BCCs, whose uncoupled ensembles suffer from a poor BP threshold. For a wide range of code rates, SC-TCs show close-to-capacity performance as the coupling memory increases. We further give a proof of threshold saturation for SC-TC ensembles with identical component encoders. In particular, we show that the DE of SC-TC ensembles with identical component encoders can be properly rewritten as a scalar recursion. This allows us to define potential functions and prove threshold saturation using the proof technique recently introduced by Yedla et al.
Autors: Saeedeh Moloudi;Michael Lentmaier;Alexandre Graell i Amat;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6199 - 6215
Publisher: IEEE
 
» Spatiotemporal Reconstruction of Land Surface Temperature Derived From FengYun Geostationary Satellite Data
Abstract:
The FengYun-2F (FY-2F) geostationary satellite land surface temperature (LST) and its diurnal variation are important when evaluating climate change, the land-atmosphere energy budget, and the hydrological cycle. However, the presence of clouds generates numerous meaningless pixels that constrain the potential application of the available satellite LST products. These pixels covered by cloud are assigned –2, and otherwise are the LST values, based on the result of a double-channel threshold cloud detection algorithm. This paper proposes a combined temporal and spatial information reconstruction method for the missing FY-2F LST data reconstruction with a good spatial continuity, where cloud detection has already been undertaken. Compared with the methods used in the past, the main characteristics of the proposed method are: 1) the consideration of a free parameter when modeling the diurnal temperature cycle curve; 2) the introduction of the genetic algorithm for solving the parameters; 3) the adoption of the spectral multimanifold clustering algorithm for clustering the multitemporal geostationary satellite LST data; and 4) the accurate and efficient combined temporal and spatial reconstruction method. The proposed combined temporal and spatial reconstruction method was tested and quantitatively assessed with both simulated and real data experiments, using the FY-2F LST products. The results indicate that the combined reconstruction method is accurate to within about 2 °C, which can significantly improve the practical value of FY-2F LST datasets.
Autors: Zihan Liu;Penghai Wu;Sibo Duan;Wenfeng Zhan;Xiaoshuang Ma;Yanlan Wu;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4531 - 4543
Publisher: IEEE
 
» Spectral–Spatial Rotation Forest for Hyperspectral Image Classification
Abstract:
Rotation Forest (RoF) is a recent powerful decision tree (DT) ensemble classifier of hyperspectral images. RoF exploits random feature selection and data transformation techniques to improve both the diversity and accuracy of DT classifiers. Conventional RoF only considers data transformation on spectral information. To overcome this limitation, we propose a spectral and spatial RoF (SSRoF), to further improve the performance. In SSRoF, pixels are first smoothed by the multiscale (MS) spatial weight mean filtering. Then, spectral–spatial data transformation, which is based on a joint spectral and spatial rotation matrix, is introduced into the RoF. Finally, classification results obtained from each scale are integrated by a majority voting rule. Experimental results on two datasets indicate the competitive performance of the proposed method when compared to other state-of-the-art methods.
Autors: Junshi Xia;Lionel Bombrun;Yannick Berthoumieu;Christian Germain;Peijun Du;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4605 - 4613
Publisher: IEEE
 
» Spectral-Density-Based Graph Construction Techniques for Hyperspectral Image Analysis
Abstract:
The past decade has seen the emergence of many hyperspectral image (HSI) analysis algorithms based on graph theory and derived manifold coordinates. The performance of these algorithms is inextricably tied to the graphical model constructed from the spectral data, i.e., the community structure of the spectral data must be well represented to extract meaningful information. This paper provides a survey of many spectral graph construction techniques currently used by the hyperspectral community and discusses their advantages and disadvantages for hyperspectral analyses. A focus is provided on techniques influenced by spectral density from which the concept of community structure arises. Two inherently density-weighted graph construction techniques from the data mining literature, shared nearest neighbor (NN) and mutual proximity, are also introduced and compared as they have not been previously employed in HSI analyses. Density-based edge allocation is demonstrated to produce more uniform NN lists than nondensity-based techniques by demonstrating an increase in the number of intracluster edges and improved -NN classification performance. Imposing the mutuality constraint to symmetrify an adjacency matrix is demonstrated to be beneficial in most circumstances, especially in rural (less cluttered) scenes. Surprisingly, many complex edge-reweighting techniques are shown to slightly degrade NN list characteristics. An analysis suggests this condition is possibly attributable to the validity of characterizing spectral density by a single variable representing data scale. As such, these complex edge-reweighting techniques may need to be modified to increase their effectiveness, or simply not be used.
Autors: Jeffrey R. Stevens;Ronald G. Resmini;David W. Messinger;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5966 - 5983
Publisher: IEEE
 
» Spectrum and Energy-Efficient Beamspace MIMO-NOMA for Millimeter-Wave Communications Using Lens Antenna Array
Abstract:
The recent concept of beamspace multiple input multiple output (MIMO) can significantly reduce the number of required radio frequency (RF) chains in millimeter-wave (mmWave) massive MIMO systems without obvious performance loss. However, the fundamental limit of existing beamspace MIMO is that the number of supported users cannot be larger than the number of RF chains at the same time-frequency resources. To break this fundamental limit, in this paper, we propose a new spectrum and energy-efficient mmWave transmission scheme that integrates the concept of non-orthogonal multiple access (NOMA) with beamspace MIMO, i.e., beamspace MIMO-NOMA. By using NOMA in beamspace MIMO systems, the number of supported users can be larger than the number of RF chains at the same time-frequency resources. In particular, the achievable sum rate of the proposed beamspace MIMO-NOMA in a typical mmWave channel model is analyzed, which shows an obvious performance gain compared with the existing beamspace MIMO. Then, a precoding scheme based on the principle of zero forcing is designed to reduce the inter-beam interferences in the beamspace MIMO-NOMA system. Furthermore, to maximize the achievable sum rate, a dynamic power allocation is proposed by solving the joint power optimization problem, which not only includes the intra-beam power optimization, but also considers the inter-beam power optimization. Finally, an iterative optimization algorithm with low complexity is developed to realize the dynamic power allocation. Simulation results show that the proposed beamspace MIMO-NOMA can achieve higher spectrum and energy efficiency compared with the existing beamspace MIMO.
Autors: Bichai Wang;Linglong Dai;Zhaocheng Wang;Ning Ge;Shidong Zhou;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Oct 2017, volume: 35, issue:10, pages: 2370 - 2382
Publisher: IEEE
 
» Spectrum Width Estimation Using Matched Autocorrelations
Abstract:
The matched-autocorrelation spectrum-width estimator is introduced; statistics are derived and compared to those of the conventional estimator. It is demonstrated that the proposed estimator exhibits improved performance for narrow spectrum widths without increased computational complexity.
Autors: David A. Warde;Sebastian M. Torres;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1661 - 1664
Publisher: IEEE
 
» Split-Gate 1.2-kV 4H-SiC MOSFET: Analysis and Experimental Validation
Abstract:
The 1.2-kV-rated 4H-SiC Split Gate MOSFET (SG-MOSFET) structure is demonstrated to have a superior high-frequency figures-of-merit (HF-FOMs) by numerical simulations, with experimental validation for the first time. Excellent electrical characteristics (specific on-resistance, threshold voltage, breakdown voltage, reverse transfer capacitance, and gate-to- drain charge) were measured from devices fabricated on a 6-in SiC wafer. Compared with the conventional MOSFET, the SG-MOSFET has smaller HF-FOM [] due to the reduced gate-to-drain charge.
Autors: Kijeong Han;B. J. Baliga;Woongje Sung;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1437 - 1440
Publisher: IEEE
 
» SPM-Improved Transmission Performance of Software-Reconfigurable IMDD PONs Based on Digital Orthogonal Filtering
Abstract:
Extensive explorations are undertaken of the feasibility of utilizing self-phase modulation (SPM) to mitigate the channel fading effect associated with digital-orthogonal-filtering-enabled software-reconfigurable intensity-modulation direct-detection passive optical networks (PONs). A comprehensive theoretical model is developed and subsequently verified, based on which numerical simulations are undertaken to investigate the effectiveness of the effects of both SPM and adaptive channel power loading in maximizing the signal transmission capacity of each individual channel in the aforementioned PON systems. It is shown that, for the channel experiencing the worst channel fading effect, the SPM effect can enhance its transmission capacity by a factor as large as 2, and a further 45% transmission capacity improvement is also obtainable when adaptive channel power loading is applied. The signal transmission capacity improvement enabled by the coexistence of these two effects increases almost linearly with transmission distance. The research work not only provides a new means for dynamically manipulating the signal transmission capacity of each individual channel, but also allows the utilization of low-cost optical components without comprising the overall PON system performance.
Autors: Xiaoxue Gong;Lei Guo;Yixian Dong;Mingliang Deng;Roger Philip Giddings;J. M. Tang;
Appeared in: Journal of Lightwave Technology
Publication date: Oct 2017, volume: 35, issue:20, pages: 4488 - 4496
Publisher: IEEE
 
» Sputnik at 60 [Numbers Don't Lie]
Abstract:
SIXTY YEARS AGO, ON FRIDAY, 4 OCTOBER 1957, the Soviet Union launched Sputnik 1, the first artificial satellite. Technically, it was a modest affair, a sphere 58 centimeters in diameter weighing almost 84 kilograms and sprouting four rodlike aerials. Although its three silver-zinc batteries made up some 60 percent of the total mass, they rated only 1 watt, good enough to broadcast rapid shrill beeps at 20.007 and 40.002 megahertz for three weeks. The satellite circled the planet 1,440 times before plunging to a fiery death on 4 January 1958. Sputnik should have come as no surprise. Both the Soviets and the United States had revealed their intent to launch orbiting satellites during the International Geophysical Year (1957-1958), and the Soviets had even published some technical details before the launch. In retrospect, it's fair to call Sputnik just the inevitable first act in a long-running show. But that was not how the public perceived the little beeping sphere in late 1957.
Autors: Vaclav Smil;
Appeared in: IEEE Spectrum
Publication date: Oct 2017, volume: 54, issue:10, pages: 20 - 20
Publisher: IEEE
 
» SSIM-Motivated Two-Pass VBR Coding for HEVC
Abstract:
We propose a structural similarity (SSIM)-motivated two-pass variable bit rate control algorithm for High Efficiency Video Coding. Given a bit rate budget, the available bits are optimally allocated at group of pictures (GoP), frame, and coding unit (CU) levels by hierarchically constructing a perceptually uniform space with an SSIM-inspired divisive normalization mechanism. The Lagrange multiplier , which controls the tradeoff between perceptual distortion and bit rate, is adopted as the GoP level complexity measure. To derive , Laplacian distribution-based rate and perceptual distortion models are established after the first pass encoding, and the target bits are dynamically allocated by maintaining a uniform Lagrange multiplier level for each GoP through equalization. Within each GoP, rate control is further performed at frame and CU levels based on SSIM-inspired divisive normalization, aiming to transform the prediction residuals into a perceptually uniform space. Experiments show that the proposed scheme achieves high accuracy rate control and superior rate-SSIM performance, which is further verified by subjective visual testing.
Autors: Shiqi Wang;Abdul Rehman;Kai Zeng;Jiheng Wang;Zhou Wang;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Oct 2017, volume: 27, issue:10, pages: 2189 - 2203
Publisher: IEEE
 
» Stability Analysis of Selected Speed Estimators for Induction Motor Drive in Regenerating Mode—A Comparative Study
Abstract:
This paper deals with the stability problem of selected induction motor speed estimators in the case of the regenerating mode operation. Two effective solutions are taken into consideration: adaptive full-order observer and model reference adaptive system-type estimator based on the current flux model and stator current estimation. The two estimation algorithms are compared in detail, namely their mathematical models, theoretical stability analysis, unstable operation areas, and stability improvement methods. The speed adaptation mechanism is extended with an additional shift angle in both cases. The theoretical analysis and simulation test results are validated by wide experimental tests.
Autors: Teresa Orlowska-Kowalska;Mateusz Korzonek;Grzegorz Tarchała;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7721 - 7730
Publisher: IEEE
 
» Stability and Performance Analysis of Spatially Invariant Systems with Networked Communication
Abstract:
In this paper, tractable stability and performance conditions are presented for systems consisting of an infinite number of spatially invariant, i.e., identical subsystems that are described by (non)linear differential equations and interconnected (partly) through packet-based communication networks. These networks transmit packets asynchronously and independently of each other and are equipped with scheduling protocols that determine which actuator, sensor, or controller node is allowed access to the network. The overall system is modeled as an infinite interconnection of spatially invariant hybrid subsystems. To underline the relevance of this framework, it is shown how two well-known and natural system configurations can be captured in this hybrid modeling framework. Moreover, for the resulting overall infinite-dimensional hybrid system, a proper solution concept is introduced, which is necessary as many standard concepts do not apply as Zeno behavior is inevitable for the systems under study. Based on the proposed hybrid modeling framework, conditions leading to a maximally allowable transmission interval (MATI) for all of the individual communication networks are derived such that uniform global asymptotic stability (UGAS) or -stability of the overall system is guaranteed. Interestingly, by exploiting the interconnection structure, the conditions guaranteeing UGAS or -stability can be stated locally in the sense that they only involve the (local) dynamics of one subsystem in the interconnection and local conditions on the scheduling protocol. Finally, it is shown that in the linear case the derived conditions can even be stated in terms of “local” LMIs, making them amenable for computational verification.
Autors: S. H. J. Heijmans;D. P. Borgers;W. P. M. H. Heemels;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 4994 - 5009
Publisher: IEEE
 
» Stability Enhanced Online Powdery Cement Raw Materials Quality Monitoring Using Laser-Induced Breakdown Spectroscopy
Abstract:
Mastering the change of cement raw materials composition in real time has important significance to timely adjusting the proportion of raw materials and improving the quality of cement products. As a result, a greater need for online chemical sensors is evolving. Laser-induced breakdown spectroscopy (LIBS) possesses many of the characteristics required for such online chemical sensing, and is a promising technique for field measurements in harsh industrial environments. In this work, we developed a LIBS device for online cement raw materials quality monitoring in the way of ejecting gas-powder mixture, and enhanced the measurement stability through approaches including powder concentration of the ejected gas-powder stream stabilization, pulsed laser power stabilization, and optical efficiency enhancement.
Autors: Lei Zhang;Wangbao Yin;Lei Dong;Weiguang Ma;Liantuan Xiao;Suotang Jia;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Stability of Synchronous Solutions in a Directed Kuramoto-Oscillator Network With a Pacemaker
Abstract:
In this brief, we investigate the stability of a directed Kuramoto-oscillator network with a pacemaker for two kinds of synchronous solutions. Sufficient conditions on the coupling strength and initial phases to achieve such synchronous solutions are explicitly provided under the assumption that the augmented digraph has a directed spanning tree rooted at the pacemaker. Moreover, the minimum number of pinned oscillators is determined under the given conditions.
Autors: Pengchun Rao;Xiang Li;Maciej J. Ogorzalek;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Oct 2017, volume: 64, issue:10, pages: 1222 - 1226
Publisher: IEEE
 
» Stabilized Liner Compressor for Low-Cost Controlled Fusion at Megagauss Field Levels
Abstract:
The notion of employing very high magnetic fields for fusion has been extended to so-called magnetized-target fusion (MTF), which may comprise both magnetic and inertial-confinement fusion schemes, and magneto-inertial fusion (MIF) in which the inertia of the liner is explicitly recognized for compressing and holding fusion plasma at relatively high density. Recently, the U.S. Department of Energy through ARPA-E has initiated the ALPHA program for technologies that will enable the development of low-cost controlled fusion by MIF. While it is certainly possible to continue the past history of single-shot implosions of liners onto plasma targets, it has become clear that some means for performing frequent laboratory experiments at multimegajoule levels are needed for reasonable progress. To develop the necessary plasma targets for liner compression requires hundreds of shots, so technology for low cost, repetitive experiments must be created and demonstrated. Furthermore, to satisfy overall program goals, these techniques must extend to break-even experiments and economical fusion power reactors. The stabilized liner compressor (SLC) seeks to accomplish these goals by means of pneumatically driven, annular free-pistons imploding rotationally stabilized liquid metal liners. We review the basic concept, including the reactor embodiment, and discuss the liner and plasma issues for SLC.
Autors: Peter J. Turchi;Sherry D. Frese;Michael H. Frese;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2800 - 2809
Publisher: IEEE
 
» Stable Thin-Film Reference Electrode on Plastic Substrate for All-Solid-State Ion-Sensitive Field-Effect Transistor Sensing System
Abstract:
Solid-state thin-film reference electrodes (REs) were fabricated on plastic substrate based on a titanium/gold/silver/silver chloride (Ti/Au/Ag/AgCl) multi-layer metal structure for ion-sensitive field-effect-transistor (ISFET)-based sensing systems. A porous structure polyvinyl butyral membrane was formed on top to maintain a constant concentration of chloride as well as acting as a bridge between the electrolyte inside the membrane and the test solution. Excellent measurement stability was achieved with the fabricated RE, with a small drift rate of the open circuit potential less than 1.7 mV per hour. An all-solid-state ISFET sensing system was thus able to be built using the RE for pH measurement, showing excellent reproducibility. The system was finally applied for measuring different beverages, and the measurement results agreed well with those obtained with a commercial pH meter.
Autors: Qiaofeng Li;Wei Tang;Yuezeng Su;Yukun Huang;Sai Peng;Bengang Zhuo;Shi Qiu;Li Ding;Yuanzhe Li;Xiaojun Guo;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1469 - 1472
Publisher: IEEE
 
» Stateful Reconfigurable Logic via a Single-Voltage-Gated Spin Hall-Effect Driven Magnetic Tunnel Junction in a Spintronic Memory
Abstract:
Stateful in-memory logic (IML) is a promising paradigm to realize the unity of data storage and processing in the same die, exhibiting great feasibility to break the bottleneck of the conventional von Neumann architecture. On the roadmap toward developing such a logic platform, a critical step is the effective and efficient realization of a complete set of logic functions within a memory. In this paper, we report a realization of stateful reconfigurable logic functions via a single three-terminal magnetic tunnel junction (MTJ) device within a spintronic memory by exploiting the novel voltage-gated spin Hall-effect driven magnetization switching mechanism. This proposed reconfigurable IML methodology can be implemented within either a typical memory array or a cross-point array architecture. The feasibility of the proposed approach is successfully demonstrated with hybrid MTJ/CMOS circuit simulations. We believe our work may promote the research and development of the revolutionary IML for future non-von Neumann architectures.
Autors: He Zhang;Wang Kang;Lezhi Wang;Kang L. Wang;Weisheng Zhao;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4295 - 4301
Publisher: IEEE
 
» Static Output-Feedback Control of Markov Jump Linear Systems Without Mode Observation
Abstract:
In this paper, we address infinite-horizon optimal control of Markov Jump Linear Systems (MJLS) via static output feedback. Because the jump parameter is assumed not to be observed, the optimal control law is nonlinear and intractable. Therefore, we assume the regulator to be linear. Under this assumption, we first present sufficient feasibility conditions for static output-feedback stabilization of MJLS with nonobserved mode in the mean square sense in terms of linear matrix inequalities (LMIs). However, these conditions depend on the particular state-space representation, i.e., a coordinate transform can make the LMIs feasible, while the original LMIs are infeasible. To avoid the issues with the ambiguity of the state-space representation, we, therefore, present an iterative algorithm for the computation of the regulator gain. The algorithm is shown to converge if the MJLS is stabilizable via mode-independent static output feedback. However, convergence of the algorithm is not sufficient for the stability of the closed loop, which requires an additional stability check after the regulator gains have been computed. A numerical example demonstrates the application of the presented results.
Autors: Maxim Dolgov;Uwe D. Hanebeck;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5401 - 5406
Publisher: IEEE
 
» Stay Current and Earn Continuing Education Credits [Education News]
Abstract:
Presents a listing of educational webinars sponsored by the IEEE Industry Applications Society.
Autors: Iqbal Husain;
Appeared in: IEEE Industry Applications Magazine
Publication date: Oct 2017, volume: 23, issue:5, pages: 71 - 71
Publisher: IEEE
 
» Steady Delivery: Wireless Local Positioning Systems for Tracking and Autonomous Navigation of Transport Vehicles and Mobile Robots
Abstract:
For many players in the service and manufacturing sectors, the cost associated with transportation processes is a key factor in competitiveness and market success. Innovations such as wireless connectivity, RF identification (RFID), and the Internet of Things have already transformed these industries, and this trend-stimulated by modern wireless technologies, wave-based imaging systems, and autonomous driving-is set to continue.
Autors: Yassen Dobrev;Martin Vossiek;Mark Christmann;Igor Bilous;Peter Gulden;
Appeared in: IEEE Microwave Magazine
Publication date: Oct 2017, volume: 18, issue:6, pages: 26 - 37
Publisher: IEEE
 
» Steady-State Matching and Model Reduction for Systems of Differential–Algebraic Equations
Abstract:
The problem of model reduction for nonlinear differential–algebraic systems is addressed using the notions of moment and of steady-state response. These notions are formally introduced for this class of systems and families of nonlinear differential–algebraic reduced-order models achieving moment matching with additional properties are presented. Stronger results for the special class of linear singular systems are provided. Two simple examples illustrate the proposed technique.
Autors: Giordano Scarciotti;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5372 - 5379
Publisher: IEEE
 
» Steel Surface Defect Detection Using a New Haar–Weibull-Variance Model in Unsupervised Manner
Abstract:
Automatic defect detection on the steel surface is a challenging task in computer vision, owing to miscellaneous patterns of the defects, low contrast between the defect and background, the existence of pseudo defects, and so on. In this paper, a new Haar-Weibull-variance (HWV) model is proposed for steel surface defect detection in an unsupervised manner. First, an anisotropic diffusion model is utilized to eliminate the influence of pseudodefects. Second, a new HWV model is established to characterize the texture distribution of each local patch in the image. The proposed model can project the texture distribution of each patch into the low-dimensional space with only two parameters. The parameter distribution of the whole image can also be unified into the form of linear radiation in an Euclidean space. The reliable background can be extracted via the formation of parameter distribution, by which the model parameter can be optimized further. Finally, the adaptive threshold can be determined to distinguish the defect from the background. Experimental results show that the proposed method can detect an arbitrary type of defect on the homogeneously textured surface and achieve an average detection rate of 96.2% on the data set, which outperforms the previous methods.
Autors: Kun Liu;Heying Wang;Haiyong Chen;Erqing Qu;Ying Tian;Hexu Sun;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Oct 2017, volume: 66, issue:10, pages: 2585 - 2596
Publisher: IEEE
 
» Still Beheading Hydras: Botnet Takedowns Then and Now
Abstract:
Devices infected with malicious software typically form botnet armies under the influence of one or more command and control (C&C) servers. The botnet problem reached such levels where federal law enforcement agencies have to step in and take actions against botnets by disrupting (or “taking down”) their C&Cs, and thus their illicit operations. Lately, more and more private companies have started to independently take action against botnet armies, primarily focusing on their DNS-based C&Cs. While well-intentioned, their C&C takedown methodology is in most cases ad-hoc, and limited by the breadth of knowledge available around the malware that facilitates the botnet. With this paper, we aim to bring order, measure, and reason to the botnet takedown problem. We improve an existing takedown analysis system called rza. Specifically, we examine additional botnet takedowns, enhance the risk calculation to use botnet population counts, and include a detailed discussion of policy improvements that can be made to improve takedowns. As part of our system evaluation, we perform a postmortem analysis of the recent 3322.org, Citadel, and No-IP takedowns.
Autors: Yacin Nadji;Roberto Perdisci;Manos Antonakakis;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Oct 2017, volume: 14, issue:5, pages: 535 - 549
Publisher: IEEE
 
» Stochastic Approach for Feature-Based Tip Localization and Planning in Nanomanipulations
Abstract:
In atomic force microscopy (AFM)-based nanomanipulation, the tip position uncertainties still exist due to the parameter inaccuracies in the open-loop compensation of the piezo scanner, the noise in the closed-loop control and thermal drift. These spatial uncertainties are very challenging to be directly estimated owing to the lack of real-time feedback, and its effects are more significant in performing an automatic nanomanipulation/assembly task than macro world manipulations. In this paper, we propose a stochastic framework for feature-based localization and planning in nanomanipulations to cope with these uncertainties. In the proposed framework, some features in the sample surface are identified to calculate their positions in statistics, and detected by using the AFM tip as the sensor itself through a local scan-based motion. In the localization, the Kalman filter is used through incorporating the tip motion model and the local scan-based observation model to estimate the on-line tip position in the task space. The simulation and experiments about tip positioning are carried out to illustrate the validity and feasibility of the proposed algorithm. Then, positioning tip for effective nanomanipulation is presented by using several experiments. Finally, a carbon nanotube is followed to show that the proposed method can provide a great potential for improving the position accuracy.

Note to Practitioners—Atomic force microscopy (AFM)-based nanomanipulation has become a promising approach in developing devices and structures at nanoscale. One of the prerequisites for the effective and successful nanomanipulation is that the AFM tip position relative to the interest region can be controlled accurately. This paper proposes a stochastic approach for feature-based localization and planning method to solve these problems. The uncertainties of the tip position are decreased by using the Kalman filter method in the localization pr- cedure. Fifty times of experiments are represented to illustrate the effectiveness and efficiency of the tip positioning method. Then, basic nanomanipulations in the vertical direction without and with SAFLP method are performed for representing significance of positioning the tip. Furthermore, assembling nanostructures and following the carbon nanotube are carried out by using SAFLP. These experiments indicate that accurate positioning tip in AFM-based observation and manipulation can provide valid nanomanipulation in N/MEMS assembly, and the following nano-objects such as nanotube in real-time observation, which will promote automation implementation in nanomanipulation.

Autors: Shuai Yuan;Zhidong Wang;Lianqing Liu;Ning Xi;Yuechao Wang;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Oct 2017, volume: 14, issue:4, pages: 1643 - 1654
Publisher: IEEE
 
» Stokes Space Representation of Modal Dispersion
Abstract:
Polarization-mode dispersion in single-mode fibers can be viewed as a special case of modal dispersion in multimode and multicore optical fibers. Exploiting the similarity between these two transmission effects, modal dispersion can be modeled in a way analogous to that of polarization-mode dispersion by modifying the conventional Jones–Stokes formalism. In this paper, we review the geometrical representation of modal dispersion in the generalized Stokes space by means of the modal dispersion vector. We summarize and unify the fundamental equations that encapsulate the properties of the modal dispersion vector. We prove that the modal dispersion vector can be expressed as a linear superposition of the Stokes vectors representing the principal modes. The coefficients of this expansion are the corresponding differential mode group delays. This concise and elegant expression can be considered as a simplified definition of the modal dispersion vector and can be used to facilitate analytical calculations.
Autors: Ioannis Roudas;Jaroslaw Kwapisz;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 15
Publisher: IEEE
 
» Straightforward Measurement Method of Common Source Inductance for Fast Switching Semiconductor Devices Mounted on Board
Abstract:
Recent progress of widebandgap semiconductor switching devices enabled extremely high-frequency operation of power converters owing to their ultrafast switching capability. Fast switching may cause large switching noise at the common source inductance, which may increase the switching loss and lead to false triggering. Therefore, measurement of the common source inductance is often intensely required in practical design of fast switching power converters. However, measurement of the common source inductance is difficult, because 1) the wiring path hidden beneath the molded package significantly contributes to this inductance, 2) the mutual inductance between the gating circuit and the power circuit also contributes to this inductance, and 3) this inductance cannot be defined as the stray inductance of a loop wiring path. These difficulties are addressed in this paper by proposing a novel measurement method of the common source inductance. The proposed method is applicable to already-mounted power circuits. In addition, the proposed method offers a straightforward measurement procedure with common instruments, such as a signal generator, an oscilloscope, and voltage and current probes. Along with the measurement principle, this paper also presents an experiment to evaluate the proposed method.
Autors: Kazuhiro Umetani;Kyota Aikawa;Eiji Hiraki;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8258 - 8267
Publisher: IEEE
 
» Strain Dynamic Range Enlargement of Slope-Assisted BOTDA by Using Brillouin Phase-Gain Ratio
Abstract:
A novel technique to enlarge the dynamic range of strain measurement for slope-assisted Brillouin optical time domain analysis (SA-BOTDA) is proposed by introducing a new parameter called Brillouin phase-gain ratio, which combines Brillouin phase shift and Brillouin gain. With the new technique, the dynamic range of strain measurement can be enlarged, and the pump-power-dependency problem mitigated. In the experiment, a 100-MHz frequency span of linear slope is demonstrated with a 25-ns pump pulse, which is 3.3 times of that in conventional SA-BOTDA, and a dynamic strain with a large amplitude of about 1000 is successfully measured.
Autors: Guangyao Yang;Xinyu Fan;Zuyuan He;
Appeared in: Journal of Lightwave Technology
Publication date: Oct 2017, volume: 35, issue:20, pages: 4451 - 4458
Publisher: IEEE
 
» Strain-Induced Armchair Graphene Nanoribbon Resonant-Tunneling Diodes
Abstract:
The electronic properties of armchair graphene nanoribbons (AGNRs) can be changed and modified under the uniaxial strain. Taking this advantage, we propose a new platform of AGNR-based resonant-tunneling diode (RTD) using the effects of strain for the first time. In this RTD platform, barrier regions are composed of strained AGNR, whereas channel is made up by pristine AGNR. The calculated results show that the double barrier quantum well is performed for such device, and negative differential resistance property appears in – characteristic. In addition, performance of strain-induced 12-AGNR-RTD is explored under the variation of strain percentage (). It is realized that the efficiency of such devices consist of peak to valley ratio can be engineered by setting strain percentage () to appropriate orders. Tight binding model coupled with nonequilibrium Green’s function formalism is derived for this paper.
Autors: Milad Zoghi;Arash Yazdanpanah Goharrizi;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4322 - 4326
Publisher: IEEE
 
» Structure Preserving Transfer Learning for Unsupervised Hyperspectral Image Classification
Abstract:
Recent advances on remote sensing techniques allow easier access to imaging spectrometer data. Manually labeling and processing of such collected hyperspectral images (HSIs) with a vast quantities of samples and a large number of bands is labor and time consuming. To relieve these manual processes, machine learning based HSI processing methods have attracted increasing research attention. A major assumption in many machine learning problems is that the training and testing data are in the same feature space and follow the same distribution. However, this assumption doesn’t always hold true in many real world problems, especially in certain HSI processing problems with extremely insufficient or even without training samples. In this letter, we present a transfer learning framework to address this unsupervised challenge (i.e., without training samples in the target domain), by making the following three main contributions: 1) to the best of our knowledge, this is the first time for transfer learning framework to be used for the classification of totally unknown target HSI data with no training samples; 2) the characteristics of HSI are learned on dual spaces to exploit its structure knowledge to better label HSI samples; and 3) two specific new scenarios suitable for transfer learning are investigated. Experimental results on several real world HSIs support the superiority of the proposed work.
Autors: Jianzhe Lin;Chen He;Z. Jane Wang;Shuying Li;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1656 - 1660
Publisher: IEEE
 
» STT Analysis of the Time-Dependent Reflected Field From a Moving Dielectric–Magnetic Planar Discontinuity
Abstract:
This paper is concerned with obtaining closed-form exact solution for the 2-D canonical problem of the reflected field from a moving planar discontinuity of a dielectric–magnetic medium that is excited by an impulsive line current. The spectral theory of transient (STT) that originally deals with nondispersive frequency-domain plane-wave spectra is used in this paper for addressing a time-variant scattering problem. The scattering from a moving object yields dispersive and anisotropic PW spectra. Nevertheless, we demonstrate that the STT is capable of dealing with these types of spectra and obtain the desired exact time-dependent solutions. The unique wave phenomena that are associated with the medium and scatterer velocity are explored.
Autors: Timor Melamed;Tatiana Danov;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5238 - 5244
Publisher: IEEE
 
» Student Paper Contest at the 2017 IEEE AP-S\/U.S. National Committee - International Union for Radio Science Symposium [Education Corner]
Abstract:
Presents information on the APS society's Student Paper Contest at the 2017 IEEE International Union for Radio Science Symposium. The competition was held at the 2017 IEEE Antennas and Propagation Society (AP-S)/U.S. National Committee–International Union for Radio Science Symposium held on 9–15 July in San Diego, California.
Autors: Michael Newkirk;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 148 - 148
Publisher: IEEE
 
» Study of Stepped Amplitude Distribution Taper for Microwave Power Transmission for SSPS
Abstract:
A novel stepped amplitude distribution (SAD) taper for microwave power transmission for space solar power satellite is proposed in this paper. The SAD taper is described by the summation of the Heaviside step functions. Through optimizing the “height” and “radius” of each step of the descriptive function, the maximal beam collection efficiency (BCE) with and without constraints on the radiation levels can be obtained. A large set of numerical experiments on continuous apertures and discrete antenna arrays are carried out. The results show that the obtained BCEs can be close to or even higher than those of the 10-dB Gaussian ones, which shows the superiority of the method. In addition, only several kinds of amplifiers are required in this method, and therefore, the cost and complexity of the system can be greatly reduced.
Autors: Xun Li;Baoyan Duan;Liwei Song;Yiqun Zhang;Wanye Xu;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5396 - 5405
Publisher: IEEE
 
» Study of the Effect of a Shielding Cylinder on the Torque in a Permanent-Magnet Synchronous Machine Considering Two Torque-Producing Mechanisms
Abstract:
Despite an ever-growing interest, a lot of questions related to the design and operation of high-speed permanent-magnet synchronous machines remain unanswered. One aspect of such high-speed machines that requires special attention is the effect of the shielding cylinder (SC), a conductive sleeve that is wrapped around the magnets and which’ goal is to reduce the rotor losses and/or retain the magnets. Therefore, this paper aims at theoretically studying the effect of the SC on the torque production. The study is performed using a 2-D analytical subdomain model that accounts for slotting and the eddy-current reaction field. The torque is divided in two components, the classical torque due to interaction between the magnets and the stator currents and the torque due to interaction with the eddy currents in the SC. This approach is unique and results in a better insight in the machine’s physics.
Autors: Bert Hannon;Peter Sergeant;Luc Dupré;
Appeared in: IEEE Transactions on Magnetics
Publication date: Oct 2017, volume: 53, issue:10, pages: 1 - 8
Publisher: IEEE
 
» Study of the Phase Shift Plus PWM Control Strategy Based on a Resonant Bridge Modular Switched-Capacitor Converter
Abstract:
Bridge modular switched-capacitor converter (BMSCC) has been reported with symmetric and modular structure, and featured less output voltage ripple, less components cost, and convenient voltage extension but weak output voltage regulation. This paper presents a phase shift plus pulse width modulation (PWM) control strategy for the novel resonant BMSCC. With this control method, output voltage regulation and the limitation of the loop peak current to a proper range are implemented. Also, output voltage ripple could be effectively controlled as well through the voltage ripple characteristics analysis in different cases. Detailed analyses of the relationships between the switching phases of MOSFETs and the output voltage, the switching-phases of MOSFETs and the loop peak current are performed. Meanwhile, through optimal switching sequence, the proposed control method ensures that almost all switching devices maintain zero current switching or zero voltage switching operation, which results in high system efficiency. Using simulation software of the saber and hardware platform, the soft switching, output voltage, and peak current characteristics are verified.
Autors: Liangzong He;Chen Cheng;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2746 - 2755
Publisher: IEEE
 
» Submesoscale Tidal-Inlet Dipoles Resolved Using Stereo WorldView Imagery
Abstract:
A pair of high-resolution visible-band satellite images, acquired 65 s apart and analyzed using an optical-flow algorithm, is shown to provide a realistic snapshot of the velocity field of dipolar vortices (dipoles) emitted from the Gulf of San Jose, Argentina. The results reveal the expected counter-rotating vortices within three dipoles, as well as one monopole; the magnitude of vorticity ranges from 8 to 29 times the local Coriolis parameter. Analysis of the derived velocity and vorticity fields yields an estimate of 0.27 ms for the dipole self-propagation velocity, which is the part of the physics that allows transport of gulf-derived material into open waters. Dipole size, measured as the distance between vortex centers, increases with distance from the source area in a manner consistent with the effects of entrainment of ambient sea water. Given favorable imaging conditions, the general approach used here can provide a detailed portrayal of local circulation patterns—one suitable for use in validating high-resolution numerical models, especially in coastal areas having complex bathymetry.
Autors: George Marmorino;Wei Chen;Richard P. Mied;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1705 - 1709
Publisher: IEEE
 
» Substrate Embedded Thin-Film Inductors With Magnetic Cores for Integrated Voltage Regulators
Abstract:
High-density and high-frequency inductors (>5 MHz) enable miniaturization of power modules, and also integration of voltage regulator modules into the processor packages for higher efficiency and switching frequencies. Several advances in magnetic materials and substrate process integration are needed to meet the performance, size, and cost requirements. This paper highlights two substrate-embedded inductor approaches using magnetic paste and pre-fabricated magnetic thick laminate sheets. An innovative cavity-filling process using paste printing and hot pressing is developed to integrate magnetic paste with high magnetic filler loading into the core of standard organic laminate substrates. The hot-pressed metal/polymer composite magnetic cores showed a permeability of ~55 at 10 MHz. The other approach utilizes pre-fabricated thick magnetic sheets with a permeability of ~93 at 10 MHz. Standard panel-scale processes are adapted for high-volume manufacturing at low cost. The electrical performance of the inductors from both approaches showed good correlation between the simulated and measured data. Compared with air-core inductors with the same structure, the advanced thin-film inductors with magnetic sheet showed nine times improvement in inductance. Both these approaches can be scaled to higher frequencies with further innovation in magnetic composites.
Autors: Teng Sun;Himani Sharma;P. Markondeya Raj;Furukawa Yoshihiro;Satoshi Hachiya;Keiji Takemura;Rao Tummala;
Appeared in: IEEE Transactions on Magnetics
Publication date: Oct 2017, volume: 53, issue:10, pages: 1 - 9
Publisher: IEEE
 
» Substrate-Integrated Waveguide Dual-Mode Dual-Band Bandpass Filters With Widely Controllable Bandwidth Ratios
Abstract:
A realization method, named the design parameters ratio technique, of substrate-integrated waveguide (SIW) dual-mode dual-band bandpass filters (DM-DBBPFs) with widely controllable bandwidth ratios is presented when TE101 and TE201 modes in substrate-integrated rectangular cavities are exploited to dominate the first and second passbands, respectively. Emphasis is placed on filters design to simultaneously realize the design parameters including the external quality factors and coupling coefficients required for both passbands by determining proper offset positions of the feeding ports and coupling windows, which can easily be fixed by ratios of synthesized and for the two bands, respectively. Consequently, the fractional bandwidths (FBWs) of the two passbands can be allocated flexibly over a wide range of ratios, typically with the FBW ratio of 0.2–1.5. Three SIW DM-DBBPFs including a third-order direct-coupled one operating at 12 and 16 GHz with the identical absolute bandwidths, a third-order cross-coupled one operating at 12 and 15 GHz with the same FBWs, and a fourth-order cross-coupled one operating at 12 and 17 GHz with the FBW ratio of 0.6 are designed and fabricated to demonstrate the method.
Autors: Kang Zhou;Chun-Xia Zhou;Wen Wu;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Oct 2017, volume: 65, issue:10, pages: 3801 - 3812
Publisher: IEEE
 
» Substrate-Integrated Waveguide Power Combiner/Divider Incorporating Absorbing Material
Abstract:
In this letter, substrate-integrated waveguide (SIW) power combiner/divider incorporating absorbing material for isolation is presented. Based on the Riblet coupler theory, the proposed SIW power combiner/divider contains two extra ports to improve isolation between the dividing ports. Its longitudinal axis symmetry illustrates its equal power-dividing property, and ensuring the dividing ports to have good and balanced amplitude and phase properties. By loading the isolated ports with shaped absorbing material, an SIW power combiner/divider prototype is realized. Measured results are in good agreement with simulated ones, and a fractional bandwidth of 36% with over 15-dB isolation is achieved, which is wider than other similar SIW power dividers.
Autors: Yong Mao Huang;Wei Jiang;Haiyan Jin;Yuliang Zhou;Supeng Leng;Guoan Wang;Ke Wu;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Oct 2017, volume: 27, issue:10, pages: 885 - 887
Publisher: IEEE
 
» Sum of Squares Certificates for Stability of Planar, Homogeneous, and Switched Systems
Abstract:
We show that existence of a global polynomial Lyapunov function for a homogeneous polynomial vector field or a planar polynomial vector field (under a mild condition) implies existence of a polynomial Lyapunov function that is a sum of squares (sos) and that the negative of its derivative is also a sum of squares. This result is extended to show that such sos-based certificates of stability are guaranteed to exist for all stable switched linear systems. For this class of systems, we further show that if the derivative inequality of the Lyapunov function has an sos certificate, then the Lyapunov function itself is automatically a sum of squares. These converse results establish cases where semidefinite programming is guaranteed to succeed in finding proofs of Lyapunov inequalities. Finally, we demonstrate some merits of replacing the sos requirement on a polynomial Lyapunov function with an sos requirement on its top homogeneous component. In particular, we show that this is a weaker algebraic requirement in addition to being cheaper to impose computationally.
Autors: Amir Ali Ahmadi;Pablo A. Parrilo;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5269 - 5274
Publisher: IEEE
 
» Sun Sensor Based on a Luminance Spiking Pixel Array
Abstract:
We present a novel sun sensor concept. It is the very first sun sensor built with an address event representation spiking pixel matrix. Its pixels spike with a frequency proportional to illumination. It offers remarkable advantages over conventional digital sun sensors based on active pixel sensor (APS) pixels. Its output data flow is quite reduced. It is possible to resolve the sun position just receiving one single event operating in time-to-first-spike mode. It operates with a latency in the order of milliseconds. It has higher dynamic range than APS image sensors (higher than 100 dB). A custom algorithm to compute the centroid of the illuminated pixels is presented. Experimental results are provided.
Autors: Juan Antonio Leñero-Bardallo;Lukasz Farian;José-Maria Guerrero-Rodríguez;Ricardo Carmona-Galán;Ángel Rodríguez-Vázquez;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6578 - 6588
Publisher: IEEE
 
» Super Critical Fluid Technique to Enhance Current Output on Amorphous Silicon-Based Photovoltaic
Abstract:
A low temperature, non-destructive treatment technique with supercritical carbon dioxide mixing water was demonstrated on thin film type photovoltaic devices to enhance current output. Assembled P-I-N amorphous Si-based devices were treated in a high pressure reaction chamber. Generation of light current under indoor illumination was improved by about 80% after treatment. To clarify the origin of improvement, the drive-level capacity profiling method with capacitance–voltage (C–V) measurement was used, as it shows the relationship between defect density and location. Such measurements reveal that the amount of interface defects was significantly reduced after treatment. A dynamic reaction model was also proposed to explain the defect passivation reaction. This technique can be effectively applied to amorphous silicon solar cell devices to enhance performance.
Autors: Hsin-Lu Chen;Po-Hsun Chen;Ting-Chang Chang;Tai-Fa Young;Min-Chuan Wang;Chi-Fong Ai;Tsung-Ming Tsai;Kuan-Chang Chang;Min-Chen Chen;Yu-Ting Su;Chih-Cheng Yang;Chun-Chu Lin;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1401 - 1404
Publisher: IEEE
 
» Super-Resolution Imaging Through Scattering Medium Based on Parallel Compressed Sensing
Abstract:
Recent studies show that compressed sensing (CS) can recover sparse signal with much fewer measurements than traditional Nyquist theorem. From another point of view, it provides a new idea for super-resolution imaging, like the emergence of single pixel camera. However, traditional methods implemented measurement matrix by digital mirror device (DMD) or spatial light modulator, which is a serial imaging process and makes the method inefficient. In this paper, we propose a super resolution imaging system based on parallel compressed sensing. The proposed method first measures the transmission matrix of the scattering sheet and then recover high resolution objects by “two-step phase shift” technology and CS reconstruction algorithm. Unlike traditional methods, the proposed method realizes parallel measurement matrix by a simple scattering sheet. Parallel means that charge-coupled device camera can obtain enough measurements at once instead of changing the patterns on the DMD repeatedly. Simulations and experimental results show the effectiveness of the proposed method.
Autors: Yao Zhao;Qian Chen;Shenghang Zhou;Guohua Gu;Xiubao Sui;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 12
Publisher: IEEE
 
» Super-Resolution Reconstruction From Multiple Defocused Infrared Images of Stationary Scene
Abstract:
Infrared image has poor visual effect for its low resolution. Super-resolution reconstruction (SRR) is an effective means to address this problem. Existing SRR algorithms use well-focused images and ignore the value of defocused images generated by the infrared imaging system during focusing. The basic idea of the present study is to treat a defocused infrared image as distribution and accumulation of scene information among different pixels of the infrared detector, as well as a valid observation of the imaged subject; defocused images are the result of blurring a corresponding high resolution (HR) image using a point spread function (PSF) followed by downsampling. From this idea, we used multiple defocused images to build an observation model for HR images and propose an SRR algorithm to approach the HR images. We have developed an image degradation model by analyzing optical lens imaging, using the particle swarm optimization algorithm to estimate the PSF of the HR image, and using compressed sensing theory to implement SRR based on the noncoherent characteristics of the defocused infrared images. Experiments demonstrate that our method can be used to obtain more information about details of a scene and improve the visual effect without adding any hardware facilities, improving the recognition and interpretation of the image subject.
Autors: Yuxing Mao;Benjiang Zhao;Dongmei Yan;Haiwei Jia;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 16
Publisher: IEEE
 
» Super-Resolved Fine-Scale Sea Ice Motion Tracking
Abstract:
Monitoring sea ice activities is particularly critical to safe naval operations in the Arctic Ocean. Accurately tracking sea ice motions is essential to validate or even improve sea ice models for ice hazard forecasts at a fine scale. Fine-scale motions can be tracked from high-resolution radar or optical satellite imagery but with limited coverage. Daily motions over the entire Arctic are retrievable from passive microwave data, but at a much lower spatial resolution. Thus, providing motions at the passive microwave spatial and temporal coverage, but at an enhanced spatial resolution, will be a significant benefit. To break the resolution limitation and to boost tracking accuracy, a sequential super-resolved fine-scale sea ice motion tracking framework is proposed in which a hybrid example-based single image super-resolution algorithm is employed before the tracking procedure. Experiments demonstrate that the proposed framework significantly improves the tracking performance in both accuracy and robustness for a benchmark algorithm and a recently proposed state-of-the-art tracking algorithm.
Autors: Yang Xian;Zisis I. Petrou;Yingli Tian;Walter N. Meier;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5427 - 5439
Publisher: IEEE
 
» SUPERMAN: Security Using Pre-Existing Routing for Mobile Ad hoc Networks
Abstract:
The flexibility and mobility of Mobile Ad hoc Networks (MANETs) have made them increasingly popular in a wide range of use cases. To protect these networks, security protocols have been developed to protect routing and application data. However, these protocols only protect routes or communication, not both. Both secure routing and communication security protocols must be implemented to provide full protection. The use of communication security protocols originally developed for wireline and WiFi networks can also place a heavy burden on the limited network resources of a MANET. To address these issues, a novel secure framework (SUPERMAN) is proposed. The framework is designed to allow existing network and routing protocols to perform their functions, whilst providing node authentication, access control, and communication security mechanisms. This paper presents a novel security framework for MANETs, SUPERMAN. Simulation results comparing SUPERMAN with IPsec, SAODV, and SOLSR are provided to demonstrate the proposed frameworks suitability for wireless communication security.
Autors: Darren Hurley-Smith;Jodie Wetherall;Andrew Adekunle;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Oct 2017, volume: 16, issue:10, pages: 2927 - 2940
Publisher: IEEE
 
» Superpixels of RGB-D Images for Indoor Scenes Based on Weighted Geodesic Driven Metric
Abstract:
Serving as a key step for applications of image processing, superpixel generation has been attracting increasing attention. RGB-D images are used pervasively in scenes reconstruction and representation, benefiting from their contained depth data. In this paper, we present a novel framework for generating superpixels focus on RGB-D images of indoor scenes, based on a weighted geodesic driven metric that combines both color and geometric information. In particular, taking into account the unique structures of indoor scenarios, we first denoise the given RGB-D image, and construct the corresponding triangular mesh. A new weighted geodesic driven metric is defined by introducing a weight function constrained with normal vectors and colors. Under this metric, an energy function is defined to measure our over-segmentation of the triangular mesh, by optimizing which, we can acquire an optimal over-segmentation of the triangular mesh with object boundaries respected, such that vertices in each sub-region have similar geometric structures and color intensities. Re-mapping the over-segmentation of the triangular mesh to the RGB-D image results in desired superpixels. We perform extensive experiments on a large-scale database of RGB-D images to verify the efficacy of our algorithm. The results show that our algorithm has considerable advantages over the existing state-of-the-art methods.
Autors: Xiao Pan;Yuanfeng Zhou;Feng Li;Caiming Zhang;
Appeared in: IEEE Transactions on Visualization and Computer Graphics
Publication date: Oct 2017, volume: 23, issue:10, pages: 2342 - 2356
Publisher: IEEE
 
» Superstrate and CSRR Loaded Circularly Polarized Dual-Band Open-Ended Waveguide Antenna With Improved Radiation Characteristics and Polarization Reconfiguration Property
Abstract:
A circularly polarized dual-band open-ended waveguide (OEW) antenna, loaded with double complementary split-ring resonator (DCSRR) and superstrate, has been presented in this communication. The DCSRR has been placed on the aperture of a standard WR-90 waveguide, whereas the superstrate has been placed at an optimized distance from the aperture. Analysis and optimization have been carried out using Ansys high frequency structural simulator (HFSS) 14.0. Measured result shows two 10-dB return loss bandwidth with left-hand circular polarization. It has been shown that the antenna can be reconfigured for right-hand circular polarization by rotating the superstrate by 90°. The gain and front-to-back radiation ratio of the proposed antenna is higher than that of a conventional OEW antenna. It also provides less mutual coupling when used as an array element.
Autors: Avinash Chandra;Sushrut Das;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5559 - 5564
Publisher: IEEE
 
» Supervised Gaussian Process Latent Variable Model for Hyperspectral Image Classification
Abstract:
Discriminative features are significant for hyper-spectral image (HSI) classification. In this letter, we apply the supervised dimensionality reduction (DR) model termed supervised latent linear Gaussian process latent variable model (SLLGPLVM) for feature extraction. As a semiparametric classification model, the new model has ability in simultaneous feature extraction and classification and demonstrates high classification accuracy with only a small training set. This is therefore suitable for HSI classification. Experimental results on six real HSI data sets show that the proposed SLLGPLVM outperforms several conventional supervised DR models and the support vector machine implemented in the original spectral space.
Autors: Xinwei Jiang;Xiaoping Fang;Zhikun Chen;Junbin Gao;Junjun Jiang;Zhihua Cai;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1760 - 1764
Publisher: IEEE
 
» Supervised Machine Learning for Estimation of Target Aspect Angle From Bistatic Acoustic Scattering
Abstract:
When an aspect-dependent target is insonified by an acoustic source, distinct features are produced in the resulting bistatic scattered field. These features change as the aspect between the source and the target is varied. This paper describes the use of these features for estimation of the target aspect angle using data collected by an autonomous underwater vehicle (AUV). An experiment was conducted in November 2014 in Massachusetts Bay to collect data using a ship-based acoustic source producing 7–9-kHz linear frequency modulation (LFM) chirps insonifying a steel pipe. The true target orientation was unknown, as the target was dropped from the ship with no rotation control. The AUV Unicorn, fitted with a 16-element nose array, was deployed in data collection behaviors around the target, and the ship was moved to create two target aspects. A support vector machine regression model was trained using simulated scattering bistatic field data. This model was then used to estimate the target aspect angle from the data collected during the experiment. The difference between the estimates was consistent with experimental observations of relative source positioning. The simulation-based model appeared successful in estimating the target aspect angle despite uncertainties in target and source location and mismatch between true environment and simulation parameters.
Autors: Erin M. Fischell;Henrik Schmidt;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 759 - 769
Publisher: IEEE
 
» Suppressed Fin-LER Induced Variability in Negative Capacitance FinFETs
Abstract:
This letter investigates the impact of fin line-edge roughness (Fin-LER) on the intrinsic variation of negative capacitance FinFETs (NC-FinFETs) by TCAD atomistic simulation coupled with the Landau–Khalatnikov equation. We report a feedback mechanism stemming from the internal voltage amplification inherent in the negative capacitance FET. This feedback mechanism results in the superior immunity to Fin-LER-induced threshold-voltage and subthreshold-swing variations for NC-FinFETs as compared with the FinFET counterparts. This letter may provide insights for device/circuit designs using negative capacitance FETs.
Autors: Ho-Pei Lee;Pin Su;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1492 - 1495
Publisher: IEEE
 
» Suppression of Clutters Caused by Periodic Scatterers in GPR Profiles With Multibandpass Filtering for NDT&E Imaging Enhancement
Abstract:
Many civil infrastructures contain periodic elements for the purposes of foundation support or strength reinforcement. Good examples are the sleepers for rail track support and the rebars in reinforced concrete structures. For engineering nondestructive testing and evaluation (NDT&E) using ground penetrating radar (GPR) these periodic elements in the near subsurface act as scatterers that generate clutters in GPR profiles and mask the signature of the targets and hinder GPR's capability in defect detection and characterization. In this paper, we develop an algorithm using multibandpass filtering (MPF) technique to suppress the clutters in GPR profiles caused by periodic scatterers. We first extract the spatial information of the periodic scatterers and carry out spectral analysis to characterize the clutter energy in multiple wavenumbers. Then, we use this information to design the MPF in wavenumber domain and execute the filtering back in space domain with proper windowing. We test the effectiveness by applying the algorithm to a synthetic data set that simulates GPR survey on a railway system. The filtering results are very encouraging. We also apply MPF to the field GPR data collected on the Tibetan Railway. A fouled area in the ballast can be much clearly visualized than in the original, clutter-masked GPR profile. We also apply MPF in steel bar reinforced concrete slab and compare the results with the redatuming and migration methods. The MPF appears superior in clutter suppression caused by periodic scatters. MPF provides a practical and effective way to enhance GPR imaging in engineering NDT&E.
Autors: Jianping Xiao;Lanbo Liu;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4273 - 4279
Publisher: IEEE
 
» Surface Water Extraction From Landsat 8 OLI Imagery Using the LBV Transformation
Abstract:
Surface water extraction from remote sensing images is crucial for monitoring water resources and studying global environmental change. This study introduced a method for surface water extraction based on the LBV transformation (WE-LBV) from Landsat 8 Operational Land Imager (OLI) imagery. To avoid inadequate or redundant utilization of remote sensing data, input band combinations were selected using the band index method, and the LBV transformation equations for OLI images were subsequently derived. Characteristics of water and nonwater pixels were investigated after the LBV transformation. The established extraction rule stated that pixels should be classified as water if the B value is larger than the V value. For validation, the WE-LBV was used to extract water pixels from OLI images covering different water types and outside conditions and compared with other water indices on the global scale. Results showed that the producer accuracy (95.75%) and user accuracy (99.15%) of the WE-LBV were more stable and its overall accuracy (98.02%) and Kappa coefficient (0.9582) were higher than those of other methods. The WE-LBV classified shallow water and shadow pixels accurately, whereas other methods had problems. Water pixels with different colors and mixed pixels with water percentage higher than 80% could be extracted by the WE-LBV effectively. The WE-LBV did not require manually selected threshold, thus avoiding the effect of subjective human factors. Therefore, the WE-LBV is proposed as an accurate, simple, and robust method for surface water extraction, especially in situations when surface water needs to be identified in bulk automatically and accurately.
Autors: Tianyuan Zhang;Huazhong Ren;Qiming Qin;Chengye Zhang;Yuanheng Sun;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4417 - 4429
Publisher: IEEE
 
» Surface-Wave Coupling and Antenna Properties in Two Dimensions
Abstract:
Antennas are characterized by their gain and effective aperture area, and the coupling between two antennas in 3-D free space is governed by the Friis transmission equation. In this paper, we derive the properties of antennas in 2-D space, and the equivalent coupling equation. This is useful for evaluating surface-wave coupling between antennas that share the same ground plane or substrate. We propose a quantity which is the effective width for surface-wave coupling, and derive its value for an isotropic surface-wave radiator in two dimensions. We also determine the surface-wave directivity for dipole-like modes, which is relevant to many small planar antennas. The total coupling between two coplanar antennas is a combination of surface waves and space waves, and these two components are distinguished in simulations by calculating antenna coupling as a function of distance. Several simple examples are illustrated including patch and monopole antennas on various substrates. Quantifying the effective surface wave width can serve as a useful tool for optimizing the coupling between coplanar antennas.
Autors: Chao Wang;En Li;Daniel F. Sievenpiper;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5052 - 5060
Publisher: IEEE
 
» Survey of Australian power transformer failures and retirements
Abstract:
The utilities in Australia are currently operating in an economically constrained environment, and are therefore interested in optimizing expenditure on asset replacement. In response, the universities are working with the utilities to improve modeling of the economic life cycle of power transformers. Information on failure modes of transformers and reasons for their retirement from service are of great assistance to utilities in planning their asset management strategy. The last major failure survey of power transformers in Australia (and New Zealand) was published in 1996 [1]. Since 20 years have passed since then, it is timely to revisit failure of the transformer fleet.
Autors: Daniel Martin;Judith Marks;Tapan Saha;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Oct 2017, volume: 33, issue:5, pages: 16 - 22
Publisher: IEEE
 
» Swarm Aggregation under Fading Attractions
Abstract:
Gradient descent methods have been widely used for organizing multi-agent systems, in which they can provide decentralized control laws with provable convergence. Often, the control laws are designed so that two neighboring agents repel/attract each other at a short/long distance of separation. When the interactions between neighboring agents are moreover nonfading, the potential function from which they are derived is radially unbounded. Hence, the LaSalle's principle is sufficient to establish the system convergence. This technical note investigates, in contrast, a more realistic scenario where interactions between neighboring agents have fading attractions. In such setting, the LaSalle type arguments may not be sufficient. To tackle the problem, we introduce a class of partitions, termed dilute partitions, of formations which cluster agents according to the inter- and intra-cluster interaction strengths. We then apply dilute partitions to trajectories of formations generated by the multi-agent system, and show that each of the trajectories remains in a compact subset along the evolution, and converges to the set of equilibria.
Autors: Xudong Chen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5198 - 5204
Publisher: IEEE
 
» SWAROVsky: Optimizing Resource Loading for Mobile Web Browsing
Abstract:
Imperfect Web resource loading prevents mobile Web browsing from providing satisfactory user experience. In this article, we design and implement the SWAROVsky system to address three main issues of current inefficient Web resource loading: (1) on-demand and thus slow loading of sub-resources of webpages; (2) duplicated loading of resources with different URLs but the same content; and (3) redundant loading of the same resource due to improper cache configurations. SWAROVsky employs a dual-proxy architecture that comprises a remote cloud-side proxy and a local proxy on mobile devices. The remote proxy proactively loads webpages from their original Web servers and maintains a resource loading graph for every single webpage. Based on the graph, the remote proxy is capable of deciding which resources are “really” needed for the webpage and their loading orders, and thus can synchronize these needed resources with the local proxy of a client efficiently and timely. The local proxy also runs an intelligent and light-weight algorithm to identify resources with different URLs but the same content, and thus can avoid duplicated downloading of the same content via network. Our system can be used with existing Web browsers and Web servers, and does not break the normal semantics of a webpage. Evaluations with 50 websites show that on average our system can reduce the page load time by 43.1 percent and the network data transmission by 57.6 percent, while imposing marginal system overhead.
Autors: Xuanzhe Liu;Yun Ma;Xinyang Wang;Yunxin Liu;Tao Xie;Gang Huang;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Oct 2017, volume: 16, issue:10, pages: 2941 - 2954
Publisher: IEEE
 
» Swifter Security Scanning: Millimeter-Wave Imaging with Spin
Abstract:
Providing a deeper look beneath the surface is a key function of product security and materials scanners [1]. Until recently, only ultrasonic and X-ray systems made this possible [2]. Now, electromagnetic waves, which allow a view through nonconducting materials, offer a competitive alternative [3]. While examinations using X-ray methods are common, because of required safety regulations, this option is relatively costly. Current optical sensor systems, on the other hand, are relatively inexpensive, but they offer only limited information about the internal structure of the device under test (DUT).
Autors: Dirk Nuessler;Maik Schubert;Stefan Kose;Nils Pohl;
Appeared in: IEEE Microwave Magazine
Publication date: Oct 2017, volume: 18, issue:6, pages: 70 - 78
Publisher: IEEE
 
» Synaptic Computation Demonstrated in a Two-Synapse Network Based on Top-Gate Electric-Double-Layer Synaptic Transistors
Abstract:
In this letter, a two-synapse network with synaptic computation function is demonstrated. Solid-state electric-double-layer indium-zinc oxide-based synaptic transistors gated by silicon oxide electrolyte are used as artificial synapses. The short-term synaptic plasticity of the synaptic transistors is utilized to achieve high-frequency filter, processing frequency coding spike stimulus. The filtering characteristics of one synapse are controlled by the other one. Furthermore, we conducted synaptic computation in the two-synapse network, which demonstrates how synaptic transistors perform computational functions in neural networks.
Autors: Jiabin Wang;Yuxing Li;Renrong Liang;Ying Zhang;Weiquan Mao;Yi Yang;Tian-Ling Ren;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1496 - 1499
Publisher: IEEE
 
» Synchroextracting Transform
Abstract:
In this paper, we introduce a new time-frequency (TF) analysis (TFA) method to study the trend and instantaneous frequency (IF) of nonlinear and nonstationary data. Our proposed method is termed the synchroextracting transform (SET), which belongs to a postprocessing procedure of the short-time Fourier transform (STFT). Compared with classical TFA methods, the proposed method can generate a more energy concentrated TF representation and allow for signal reconstruction. The proposed SET method is inspired by the recently proposed synchrosqueezing transform (SST) and the theory of the ideal TFA. To analyze a signal, it is important to obtain the time-varying information, such as the IF and instantaneous amplitude. The SST is to squeeze all TF coefficients into the IF trajectory. Differ from the squeezing manner of SST, the main idea of SET is to only retain the TF information of STFT results most related to time-varying features of the signal and to remove most smeared TF energy, such that the energy concentration of the novel TF representation can be enhanced greatly. Numerical and real-world signals are employed to validate the effectiveness of the SET method.
Autors: Gang Yu;Mingjin Yu;Chuanyan Xu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8042 - 8054
Publisher: IEEE
 
» Synchrophasor-Based Intelligent Autoreclosing Scheme for Series Compensated Transmission Lines
Abstract:
In a transmission network, autoreclosing provides quick restoration of the line for transient faults and improves system stability. Autoreclosing during permanent fault may damage power system elements. This paper presents a method to block autoreclosing for permanent line-to-ground faults on multicircuit series compensated transmission line using synchronized measurements from both ends. The method utilizes measurements from the healthy phases of the line to calculate an index, which determines the persistence of a fault to control the reclosing. In the case of a transient line-to-ground fault, the index is high during the fault and zero after extinction of the secondary arc. The index can be used to modify the dead time of the recloser and thereby reclosing during fault (both transient and permanent) is prevented. The proposed method is tested using the sample data obtained from EMTDC/PSCAD simulation of an actual series compensated line in the Indian power grid. Results demonstrate the accuracy of the proposed method.
Autors: Swaroop Gajare;Ashok Kumar Pradhan;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Oct 2017, volume: 32, issue:5, pages: 2255 - 2262
Publisher: IEEE
 
» Synthesis of Reflection-Type Coupled Line All-Pass Circuit With Arbitrary Prescribed Wideband Flat Group Delay
Abstract:
In this letter, the analytical design method of a reflection-type coupled line all-pass circuit with arbitrary predefined wideband flat group delay (GD) is presented. The proposed circuit consists of 90° hybrid and coupled lines with a short-circuited load. The proposed structure is simple and does not require any iterative process to obtain optimum circuit parameters. Theoretical and experimental results are provided for validation of the proposed structure. The prototype circuits were fabricated at a center frequency of 2.5 GHz with 2 and 4 ns flat GD responses. The measurement results agreed well with the simulation and theoretical predicted results.
Autors: Girdhari Chaudhary;Yongchae Jeong;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Oct 2017, volume: 27, issue:10, pages: 876 - 878
Publisher: IEEE
 
» Synthetic Aperture Sonar Track Registration Using SIFT Image Correspondences
Abstract:
Repeat–pass synthetic aperture sonar (SAS) imaging for change detection and interferometry relies on accurate image registration. SAS image registration is usually performed using a slow correlation-based method, whereas feature-based registration is becoming more prevalent for synthetic aperture radar due to its relative computational efficiency. In this paper we propose a sonar track registration method, from which the estimated track parameters can be used to compute an image registration. The proposed method uses the scale-invariant feature transform (SIFT), a popular algorithm for feature detection and matching, and is demonstrated on a simulated repeat–pass pair of SAS images. A model of the ideal sonar track geometry is presented. A least squares method is formulated for estimating the track registration from a set of noisy feature correspondences, where random sample consensus (RANSAC) is first used to reject outliers. The resulting track parameter estimate corresponds to an image registration aligned to within 0.03 pixels over the scene, which is within the 0.1-pixel resolution recommended for interferometric processing. The ground truth for the simulated ideal data is precisely known, which allowed for the subpixel localization accuracy of SIFT correspondences to be objectively evaluated. The interaction between the RANSAC error threshold and the misregistration error was also evaluated and found to be chaotic. Overall, our results indicate the potential for features to be used for faster coarse registration to reduce the computation time of a more accurate subsequent correlation-based registration.
Autors: Victor T. Wang;Michael P. Hayes;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 901 - 913
Publisher: IEEE
 
» Systematic Relation of Estimated Travel Speed and Actual Travel Speed
Abstract:
Estimated travel speed based on spot speed measurements from detectors has been used as a proxy to actual travel speed. Recently, actual travel speeds become available as vehicles with onboard electronic devices provide actual section travel times. As a result, two different speeds can be estimated for a freeway section at a time interval: estimated travel speed takes the average of the spot speeds collected from each detector within a section at a time interval, and actual travel speed is estimated using the sampled vehicles’ actual journey speeds over the section. This paper compares the difference between estimated and actual travel speeds using both kinematic wave theory and actual observations for different traffic states. The theoretical analysis proves that there is a systematic relationship between the estimated and actual travel speeds that form a well-defined loop shape. The existence of well-defined relations is verified using real traffic speed data collected from a Korean expressway and a California freeway. Empirical analysis shows that the real data of estimated versus actual travel speeds exhibit a well-defined linear relationship rather than loop shape. The analysis also shows that the estimated travel speed is generally greater than the actual travel speed due not only to the systematic difference between estimated and actual travel speeds but also to the inherent characteristics of speed data from loop detectors. This finding provides a groundwork to calibrate the widely used estimated travel speed by exploiting the actual travel speeds that were provided by a subset of vehicles in traffic.
Autors: Hyungjoo Kim;Youngho Kim;Kitae Jang;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Oct 2017, volume: 18, issue:10, pages: 2780 - 2789
Publisher: IEEE
 
» T–S Fuzzy Model Identification Based on a Novel Hyperplane-Shaped Membership Function
Abstract:
The fuzzy membership function is a crucial factor that may affect the model structure and modeling accuracy. Although hyperplane-shaped clustering (HPSC) has been widely used in Takagi–Sugeno (T–S) fuzzy model identification, there is no well-designed membership function in these approaches. The commonly used bell-shaped Gaussian function is actually inappropriate to employ together with HPSC in fuzzy modeling. In this paper, a hyperplane-shaped fuzzy membership function is designed to match HPSC for T–S fuzzy model identification for the first time. Experimental results on several benchmark problems indicate that modeling accuracies have been greatly improved from the original modeling approach by replacing the proposed membership function.
Autors: Chaoshun Li;Jianzhong Zhou;Li Chang;Zhengjun Huang;Yongchuan Zhang;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Oct 2017, volume: 25, issue:5, pages: 1364 - 1370
Publisher: IEEE
 
» Tailorable Elastomeric Grating With Tunable Groove Density Gradient
Abstract:
This paper describes a new method for fabrication of tailorable elastomeric gratings with tunable groove density gradients based on stretching of the grating sample in a direction perpendicular to the grating line within the grating surface. The advantage of this method is that the tunable groove density gradient can be achieved by tailoring of the shape of a grating sample with uniform thickness. The groove density gradient changes as a specific function of its spatial position on the tailored surface of the elastomeric grating. The resulting tailorable elastomeric gratings can be used in the fabrication of devices such as optical position sensors and tunable optical filters.
Autors: Bin Sheng;Luwen Luo;Yuanshen Huang;Guohua Chen;Hongyan Zhou;Dawei Zhang;Songlin Zhuang;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 6
Publisher: IEEE
 
» Tapered Optical Fiber Couplers Fabricated by Droplet-Based Chemical Etching
Abstract:
This paper presents a fabrication method for 2 × 2 twisted fiber-optic directional couplers based on biconical low-loss tapered optical fibers using a two-step wet-etching technique with hydrofluoric acid-based droplets and surface tension-driven flows. The droplet-based wet etching of optical fibers allows us simple and cost-effective fabrication of tapered fibers and multiports directional couplers. The simulation results agree well with the experimental observations on the propagation losses, which can be monitored in real-time by measuring the transmitted optical powers during the chemical etching process. The fabricated 2 × 2 fiber-optic directional coupler shows wavelength-insensitive operation within the telecommunication C-band with an excess insertion loss of less than 0.5 dB.
Autors: Gyeongho Son;Youngho Jung;Kyoungsik Yu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8
Publisher: IEEE
 
» Target Detection via Bayesian-Morphological Saliency in High-Resolution SAR Images
Abstract:
The classical target detection methods in synthetic aperture radar (SAR) images are mainly dependent on the intensity differences between the targets and clutter. Although they are effective in the simple scenes with high signal-to-clutter ratio (SCR), they may lose effectiveness in the complex scenes with low SCR. Generally, in high-resolution SAR images, the targets present not only high intensities but also specific size characteristics compared with the clutter. Based on this fact, in this paper, we propose a new target detection method for high-resolution SAR images via Bayesian-morphological saliency, which mainly contains two stages: Bayesian saliency map construction and morphological saliency map construction. The Bayesian saliency map can obtain the complete structures of the bright objects including the targets of interest and some bright clutter, via the superpixel segmentation and Bayesian framework. Furthermore, the morphological saliency map can highlight the targets of interest while suppressing both the natural and man-made clutter via the size prior information of the targets. The experimental results on the miniSAR real data set show that the proposed target detection method is effective.
Autors: Zhaocheng Wang;Lan Du;Hongtao Su;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5455 - 5466
Publisher: IEEE
 
» Technological Developments in Batteries: A Survey of Principal Roles, Types, and Management Needs
Abstract:
Battery energy storage effectively stabilizes the electric grid and aids renewable integration by balancing supply and demand in real time. The importance of such storage is especially crucial in densely populated urban areas, where traditional storage techniques such as pumped hydroelectric energy storage and compressed-air energy storage are often not feasible.
Autors: Xiaosong Hu;Changfu Zou;Caiping Zhang;Yang Li;
Appeared in: IEEE Power and Energy Magazine
Publication date: Oct 2017, volume: 15, issue:5, pages: 20 - 31
Publisher: IEEE
 
» Temperature Self-Compensation High-Resolution Refractive Index Sensor Based on Fiber Ring Laser
Abstract:
In this letter, a temperature self-compensation high-resolution refractive index (RI) sensor based on intracavity intensity-modulated sensing in a fiber ring laser is demonstrated. A fiber-optic multimode interferometer based on single-mode-no-core-single-mode fiber structure is cascaded with a fiber Bragg grating and used as a reflected sensing head to enhance intensity-modulated depth. It is inserted in a fiber ring laser as a wavelength selective filter and the intracavity intensity-modulated RI sensing is induced for the output intensity of the fiber laser. Furthermore, because the lasing wavelength of the sensor system is sensitive to temperature but insensitive to external RI, the temperature self-compensation measurement can be realized. The RI sensitivity is measured to be −4.98 mW/RIU from 1.3349 to 1.3665. Correspondingly, the relative intensity sensitivity achieves −196.1 dB/RIU from 1.3349 to 1.3544 and −744.6 dB/RIU from 1.3544 to 1.3665. The resolution of the fiber laser sensor is obtained as high as RIU with the signal-to-noise ratio more than 55 dB.
Autors: Jia Shi;Yuye Wang;Degang Xu;Tiegen Liu;Wei Xu;Chao Zhang;Chao Yan;Dexian Yan;Longhuang Tang;Yixin He;Jianquan Yao;
Appeared in: IEEE Photonics Technology Letters
Publication date: Oct 2017, volume: 29, issue:20, pages: 1743 - 1746
Publisher: IEEE
 
» Temperature-Compensated $\beta$ -Multiplier Current Reference Circuit
Abstract:
This brief presents the new simple schematic for the temperature stable current references based on the well-known -multiplier circuit. The proposed reference utilizes only four MOS transistors and two lateral PNP transistors, which are usually available in standard CMOS technologies along with one well resistor. The temperature-compensation technique has a low process dependence and needs no trimming. However, resistor trimming can be used to precisely set the output current value. The circuit implementation of the proposed technique was fabricated in a standard 0.35- CMOS process to source a 16- current. The digital calibration circuit allows setting of the output current in 32 100 nA-steps. The proposed current reference achieves the supply sensitivity of several %/V without the use of the external bandgap voltage reference for the supply regulation. The measured temperature coefficient is 105 ppm/°C over the temperature range from 0 to 110 °C.
Autors: Dmitry Osipov;Steffen Paul;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Oct 2017, volume: 64, issue:10, pages: 1162 - 1166
Publisher: IEEE
 

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